Title of Invention	CIRCULATING TYPE GRAIN DRYING MACHINE.
Abstract	TITLE: CIRCULATING TYPE GRAIN DRYING MACHINE. THE CIRCULATING TYPE GRAIN DRYING MACHINE IS PROVIDED IN WHICH, AT THE GRAIN FILLING OPERATION, A CONTROLLER CAUSES A FIRST HEATED AIR GENERATOR TO OPERATE AND A SECOND HEATED AIR GENERATOR TO STOP OPERATING, AND ALSO CAUSES, ACCORDING TO THE DETECTED VALUES OF THE OUTSIDE AIR HUMIDITY FROM AN OUTSIDE AIR HUMIDITY DETECTOR, AN AIRFLOW CONTROL SECTION TO OPERATE SO AS TO CHANGE THE QUANTITY OF THE AIRFLOW BY AN AIR EXHAUST SECTION. ALSO, AT THE DRYING OPERATION, THE CONTROLLER CONTROLS THE FIRST HEATED AIR GENERATOR AND CONTROLS THE TEMPERATURE OF THE TEMPERATURE OF THE HEATED AIR SUPPLIED INTO THE DRYING SECTION ACCORDING TO THE DETECTED VALUES OF THE GRAIN WATER CONTENT VALUES AND THE GRAIN FILLING AMOUNT.

Title of Invention

CIRCULATING TYPE GRAIN DRYING MACHINE.

Abstract

TITLE: CIRCULATING TYPE GRAIN DRYING MACHINE. THE CIRCULATING TYPE GRAIN DRYING MACHINE IS PROVIDED IN WHICH, AT THE GRAIN FILLING OPERATION, A CONTROLLER CAUSES A FIRST HEATED AIR GENERATOR TO OPERATE AND A SECOND HEATED AIR GENERATOR TO STOP OPERATING, AND ALSO CAUSES, ACCORDING TO THE DETECTED VALUES OF THE OUTSIDE AIR HUMIDITY FROM AN OUTSIDE AIR HUMIDITY DETECTOR, AN AIRFLOW CONTROL SECTION TO OPERATE SO AS TO CHANGE THE QUANTITY OF THE AIRFLOW BY AN AIR EXHAUST SECTION. ALSO, AT THE DRYING OPERATION, THE CONTROLLER CONTROLS THE FIRST HEATED AIR GENERATOR AND CONTROLS THE TEMPERATURE OF THE TEMPERATURE OF THE HEATED AIR SUPPLIED INTO THE DRYING SECTION ACCORDING TO THE DETECTED VALUES OF THE GRAIN WATER CONTENT VALUES AND THE GRAIN FILLING AMOUNT.

Full Text	CIRCULATING TYPE GRAIN DRYING MACHINE BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to a. circulating type grain drying machine for drying grains, for example, an unhulled rice, wheat, etc. (2) Description of the Related Art Conventionally, there is a circulating type grain drying machine in which, for reducing the time required for drying, separately from a drying section for drying grains with heated air being supplied, there is provided a heating section for preliminarily increasing the temperature of grains (hereinafter referred to as a -"grain temperature"). For example, Japanese Patent Application Kokai Publication No. Sho 62-9174 discloses a circulating type grain drying machine for providing preliminary heating to grains, which is provided, sequentially from the top thereof, with a reservoir section for temporarily keeping grains, a heating section having a plurality of heating pipes through which the heated air generated by one burner passes, and a drying section for drying the grains by heated air introduced from each of the heating pipes. Also, Japanese Patent Application Kokai Publication No. Hei 2-309122-discloses a machine which is provided, sequentially from the top thereof, with a reservoir section, an upper drying section for effecting preliminary heating of grains equipped with a first burner, and a lower drying section for drying the grains also equipped with a second burner. Further, Japanese Patent Application No. Hei 10- 265486 in which the applicant is the same as in the present application discloses a machine which is provided, sequentially from the top thereof, with a reservoir section, a heating section for effecting preliminary heating of grains equipped with a plurality of heating pipes through which the heated air produced by a heating means passes, and a- drying section for drying the grains by the heated -air produced by a heating means provided separately from the above heating means. In the above respective conventional circulating type grain drying machines, there are respectively the following problems: With respect to the conventional machine disclosed in Japanese Patent Application Kokai Publication No. Sho 62- 9174, the heated air generated by one burner passes through and heats each heating pipe and the heated air, after the heat is taken by the heating pipes with the heated air resulting in a lower temperature, is introduced into the drying section and serves as the heated air again for drying the grains. In order to introduce heated air of a predetermined temperature into the drying section, it is necessary to raise, according to the predetermined temperature, the temperature of the heated air for heating the heating pipes. Hence, in the disclosed machine, the heating pipes cannot be heated sufficiently. Also, since the heating temperature of the heating pipes and the heated air temperature of the drying section cannot be controlled separately, a drying efficiency may not be satisfactory. In the conventional machine disclosed in Japanese Patent Application Kokai Publication No. Hei 2-309177, the drying is carried out by supplying to the grains in the upper drying section the heated air of high temperature and of small amount of airflow and, after the grain temperature has been raised, the grains are then subjected to the heated air of low temperature and of large amount of airflow in the lower drying section. Since the grains are exposed to the heated air for a long time at both the upper and lower drying sections, the quality of the grains will be afected and aggravated. Also, since the upper drying section and the lower drying section are provided respectively with separate burners, the quality deterioration of grains as mentioned above is caused thereby and, since the heated air at the upper drying section is not utilized in the lower drying section, the drying efficiency will not be satisfactory and the improvement is desired. In the machine disclosed in Japanese Patent Application No. Hei 10-265486, the heating section and the drying section are respectively provided with heating means. After the grains are subjected to a preliminary heating through the heating pipes heated up to a predetermined temperature by the heating means of the heating section, the heated air which is produced separately from the above heating means and which is lower than the grain temperature is supplied to the grains in the drying section whereby the grains are efficiently dried while the quality deterioration is being prevented. However, in this drying machine, the heating temperature of the heating pipes is set to a predetermined constant temperature, and the heated air supplied to the drying section is made lower than only the grain temperature produced by the heating section. Thus, the arrangement was not one in which, in consideration of the grain water content which varies as the drying operation progresses, the heatings temperature of the heating pipes and the heated air temperature supplied to the drying section are respectively controlled to optimum temperatures. Also, the heating section and the drying section are provided with separate heating means, and the heated air of the heating section is simply exhausted to outside the drying machine. Thus, the improvement is desired in the aspect of the drying efficiency. SUMMARY OF THE INVENTION In view of the problems in the conventional circulating type grain drying machines explained above and in order to further reduce the drying time and to enhance the drying efficiency, the inventors of the present invention aim at providing an improved circulating type drying machine with which the drying time is reduced and in which the first object is to enable the preliminary heating of the grains starting from the time of the grain filling operation, and the second object is to enable the separate controlling of the heated air temperature of the heating section and the heated air temperature of the drying section in accordance with the grain water content values during the drying operation while utilizing the heated air of the heating section. According to one aspect of the inVention, there is provided a circulating type grain drying machine, comprising: a heating section for heating grains equipped with a plurality of heating pipes through which heated air from a first: heated air generating means passes; a drying section under the heating section, for drying grains by supplying heated air having passed through each heating pipe together with heated air from a second heated air generating means; an air exhaust means for sucking the heated air of the drying section and exhausting the heated air to outside the drying machine; an exhaust airflow control section for controlling the amount of exhaust air of the air exhaust means; an outside air humidity detection means for detecting an outside air humidity; and a control means electrically connected to each of the first heated air generating means, the second heated air generating means, the exhaust airflow control section, and the outside air humidity detection means, the control means causing, during the grain filling operation, the first heated air generating means to operate and at the same time the second heated air generating means to stop to operate, and the exhaust airflow control section to operate according to the detected outside air humidity value detected by the outside air humidity detection means and to change the exhaust airflow of the air exhaust means. The control means causes the first heated air gener- ating means to operate and the second heated air generating means to stop. The control means sends a signal to the exhaust airflow control section operative according to the outside air humidity detected by the outside air humidity detection means and, by the operation of the exhaust airflow control section, the exhaust airflow from the air exhaust means is caused to be changed and the airflow in the drying section is changed. Thus, each heating pipe is heated by the heated air of the first heated air generating means, and the heated air turns to a low temperature resulting from the mixing with the outside air introduced through the second heated air generating means which is in a stopped state, and the low temperature heated air is introduced into the drying section. Since the amount of the exhaust air from the air exhaust means is changed by the exhaust airflow control- section operated according to the outside air humadity, the airflow of the low temperature heated air introduced into the drying section is changed according to the outside humidity. Thus, while flowing down between the heating pipes, the grains introduced into the drying machine are heated by the heat, conduction caused by being in contact with each heating pipe and by radiating heat of each heating pipe and, while flowing down through each grain flow-down layer, the grains are exposed to the heated air which is of a low temperature, which passes through each grain flow-down layer and the airflow of which is adapted to the outside humidity, the grains are heated without beings dried. Thus, it is possible to effect the preliminary heating of the grains during the grain filling operation in advance to the drying operation. If the grains are dried during the grain filling operation and such grains are mixed with the grains filled in the drying machine, there develops an uneven humidity state in the grains within the drying machine, which is unfavorable as it causes the grains to be unevenly dried during the subsequent drying operation. The above circulating type grain drying machine is arranged such that the airflow of the drying section during the drying operation when the exhaust airflow is not restricted by the exhaust airflow control section is used as reference and, if the outside air humidity value is above a predetermined humidity, the airflow of the air in the drying section is caused to be a first airflow which is smaller than the reference and, if the outside air humidity value is below the predetermined value, the airflow of the air in the drying section is caused to be a second airflow which is even smaller than the first airflow and, by the operation of the exhaust airflow control section, the exhaust airflow of the air exhaust means is caused to be changed. Thus, by using the airflow in the drying section when the exhaust airflow is not restricted by the exhaust airflow control section as reference, the drying machine operates with the airflow of the drying section as the first airflow which is smaller than the reference and, when the humidity is below the predetermined humidity, operates with the airflow as the second airflow which is smaller than the first airflow, and the grains in the drying section are exposed to the airflow which is adapted to the outside humidity and to the heated air of a low temperature. Thus, the grains are heated without being dried at the drying section. In the circulating type grain drying machine, it is preferable that the predetermined humidity is set to 70%. Thus, the airflow in the drying section changes with the outside air humidity of 70% as the boundary line, the grains are heated without being dried. According to another aspect of the invention/ there is provided a circulating type grain drying machine, comprising: a heating section for heating grains, equipped with a plurality of heating pipes through which heated air from a first heated air generating means passes; a drying section under the heating section, for dry- ing grains by supplying heated air having passed through each heating pipe together with heated air from a second heated air generating means; an air exhaust means for sucking the heated air of the drying section and exhausting the heated air to outside the drying machine; a drying -heated air temperature detecting means for detecting a temperature of the heated air supplied to the drying section; a heating pipe heated air temperature detecting means for detecting a temperature of the heated air supplied to the heating pipes; a water content detecting means for detecting water content values of grains; an input section for inputting the amount of filled grains; and a control means electrically connected to each of the first heated air generating means, the second heated air. generating means, the drying heated air temperature detecting means, the heating pipe heated air temperature detecting means, the water content detecting means and the input section, the control means controlling, during the drying operation, the first heated air generating means to change the temperature of the heated air supplied into each heat- ing pipe according to the detected value of water content of the grains, and the second heated air generating means to change the temperature of the heated air supplied into the drying section according to the detected value of water content of the grains and the value of filled grains. The control means controls the first heated air generating means based on the detected temperature value by the heating pipe heated air temperature detecting means so that the heated air supplied to the heating pipes becomes the temperature adapted to the grain water content value, the heating temperature of each heating pipe becomes the temperature adapted to the water content values of the grains. On the other handr since the control means controls the second heated air generating means based on the detected heated air temperature value detected by the drying heated air temperature detecting means so that the heated air supplied to the drying section becomes the temperature adapted to the grain water content value and the grain filling amount, the heated air introduced into the drying section and passed through each heating pipe is mixed with the outside air in-taken from the outside air in—taking opening and becomes the temperature adapted to the water content values and the grain filling amount. Further, the heating temperature of each heating pipe and the heated air temperature of the drying section are of temperatures which do not cause the deterioration of the grains such as by cracks. Thus, the gxairus filled in the drying machine are preliminary heated by each heating pipe heated by the temperature which is varied as the drying progresses and which is adapted to the water content of the grains. The preliminarily heated grains flow down into the drying section and, at the drying section, the heated air of the temperature adapted to the grain water content value and to the grain filling amount, thereby enabling the efficient drying operation and also enabling the re- duction in the drying time as compared with that in the conventional machine. BRIEF DESCRIPTION OF THE^PRAWINGS ° 0 - The above and other objects, features and advantages of the present invention, will be apparent from the follow- ing description of preferred embodiments of the invention explained with reference to the accompanying drawings, in which: Fig. 1 is a view showing main elements of one example of a joint-use grain drying and regulating installation according to the invention; Fig. 2 is a front view showing a circulating type grain drying machine, partially in section, according to the invention; Fig. 3 is a side view showing a circulating type grain drying machine, partially in section,, according to the invention; Fig. 4 is a control block diagram for controlling a circulating type grain drying machine according to the invention; Fig. 5 is a flow chart of grain filling operation and controlling of a circulating type grain drying machine according to the invention; and Figs. 6(a) and 6(b) are flow charts of drying operation and controlling of a circulating type grain drying machine according to the invention. PREFERRED EMBODIMENTS OF THE INVENTION With reference to Figs. 1-6, hereinafter explained are a construction of one exemplified joint-use grain drying and regulating installation, a configuration of a circulating type grain drying machine used in the installation, a method of grain filling and controlling operations, and a method of drying and controlling operations. First, Fig. 1 shows main elements of the above mentioned joint-use grain drying and regulating installation. The joint-use grain drying and regulating installation 1 is equipped with a grain receiving section 2, a rough sorter 3, a scale 4, a plurality of circulating type drying machines 5, a hull removing/fine sorting section (not shown), a silo (not shown) and an air exhaust means. The grain receiving section 2 is communicated to the rough sorter 3 through an elevator 8. The rough sorter 3 is communicated to the scale 4 arranged under the rough sorter 3. The scale 4 is communicated to a horizontal conveyor 7 provided over each drying machine 5 through an elevator 6. The horizontal conveyor 7 is provided with, at a location of each drying machine, a shutter section 9 which is used when the grains are supplied into each drying machine 5. Each shutter section 9 and an upper portion of each drying maehine 5 are communicated with each other through a feeding pipe 10. Next, structural arrangements of the circulating type drying machine 5 are explained with reference to Figs. 2 and 3. Fig. 2 is a front view, partially in section, of the machine, and Fig. 3 is a side view, also partially in section, of the machine. Here one representative drying machine 5 is explained. The drying machine 5 is provided with, sequentially from the top thereof, a reservoir section 11 for storing grains, a heating section 12 for providing preliminary heating to the grains, a drying section 13 for drying the grains by heating air, a forwarding valve 14 for forwarding the grains, and a screw conveyor 15 for discharging the grains to the conveying starting end at a lower portion of the elevator 16 explained later. The heating section 12 is provided with a plurality of heating pipes 18 upper and lower ones of which are horizontally provided in a staggered form. On the other hand, at one side 17a of the body 17 of the drying machine, there is provided a first heated air generating means 20 (hereinafter referred to as a "heating burner section") which is communicated to the heated air supplying side of each heating pipe 18 through a leading-in path 19. Within the leading-in path 19, there is provided a heating pipe temperature sensor 21 for detecting the temperature of the heated air supplied to each heating pipe 18. Further, the heating burner section 20 is equipped with the heating burner 20b which uses kerosene as fuel, and with a fuel adjusting circuit 20a which adjusts the amount of fuel supplied to the heating burner 20b. Also, between the lower level heating pipes 18, 18 opposing with each other, there is provided a level, detector 45 which detects presence or non-presence of the grains. The drying section 13 has a plurality of heated air paths 22 and a plurality of air exhaust paths 23. The heated air paths 22 and the air exhaust paths 23 are alternately provided in a row. The side surfaces of the heated air paths 22 and the air exhaust paths 23 are respectively formed by perforated plates so that the heated air is allowed to pass therethrough, and there is a grain flow-down layer 24 between the adjacent ones of the heated air paths 22 and the air exhaust paths 23. At an upper portion of the heated air leading-in side of the heated air path 22, there is provided a drying section temperature sensor 26 for detecting the temperature of the heated air. At the other side 17b of the main body 17 of the dry- ing machine, there is provided a second heated air generating means 32 (hereinafter referred to as a "drying burner section") which communicates with the heated air supplying section of each of the heated air paths 22 through a leading-in path 27. Further, the drying burner section 32 is equipped with a drying burner 32b which uses kerosene as fuel and with a fuel amount adjusting circuit 32a for adjusting the amount of the fuel supplied to the drying burner 32b. The exhaust side of the heated air of each heating pipe 18 is communicated through the leading-in path 28 so that the heated air passing through each of the heating pipe 18 is led-in the leading-in path 27, and the leading- in path 28 is equipped with an outside air taking-in opening 29 for taking-in the outside air. On one hand, at the one side 17a of the main body 17 of the drying machine, there is provided an. air exhaust means 30. The air exhaust means 30 communicates with the heated air exhausting side of each of the air exhaust paths 23 through a leading-in path 31. The air exhaust means 30 is connected through an air exhaust pipe 33 to an exhaust air treating means (not shown) for treating the exhaust air containing dust. In the vicinity of a location at which the exhaust pipe 33 and the air exhaust mean 30 are connected with each other, there is provided an exhaust airflow control section 34. The exhaust airflow control section 34, in this preferred embodiment, is provided with an airflow restricting plate 36 which rotates around a shaft 35, a motor 34a which rotates the shaft -35 and a motor driving circuit 34b. A plurality of forwarding valves 14 are provided with each of them being in a corresponding relation with respect to each of the grain flow-down layers 24. Below each of the plurality of forwarding valves 14, there is provided a screw conveyor 15. The elevator 16 stands at the side of the main body 17 of each drying machine 5. The elevator 16 is communicated with the discharging side of the screw conveyor 15 at the conveying starting end side at the lower portion, and the conveying finishing end side at the upper portion is communicated with the reservoir section 11 through a circulating pipe 16a. The circulating pipe 16a is equipped with a bi-directional valve, that is, a selector valve 16b which enables the selection either to the reservoir sec- tion 11 side or to the horizontal conveying machine 7 side. The horizontal conveying machine 1 side of the selector valve 16b is communicated with the horizontal conveying machine 7 through a pipe 16c. Further, at the lower portion of each elevator 16, there is provided a humidity meter 37 for detecting the moisture content (water content value) of the grain which is taken from within the elevator 16. Under the circulating pipe 16a and the feeding pipe 10 at the inner side of the ceiling of the main body 17 of the drying machine, there is provided a scattering plate lla for scattering the grains supplied from each of the pipes 16a, 10. Also, at the air in-taking side of the drying burner section 32, there is provided an outside air humidity sensor 38 for detecting the humidity of the outside air. Next, the configuration of the control means 39 of the circulating type drying machine 5 described above is explained with reference mainly to Fig. 4. The control means 39 has an arithmetic and control section 42 having CPU as its central or main component, and electrically connected to the arithmetic and control section 42 are an input/output circuit 40, a ROM 43 (read-only memory) for storing data, program, etc. and a RAM 46 (random access memory) for storing data. The input/output circuit 40 is electrically connected, through an A/D converter 41 for converting ah analog signal to a digital signal, to respectively the heated air pipe temperature sensor 21, the drying section temperature sensor 26, the outside air humidity sensor 38 and the humidity meter 37. Also, the input/output circuit 40 is electrically connected to respectively the input section 43, the heating burner section 20, the drying burner section 32, the level detector 45, the exhaust airflow control section 34, the air exhaust means 30, the elevator 16 and the selector valve 16b. The input section 43 selects and sets the quantity of the grains to be introduced (filling amount or quantity) into the main body 17 of the drying machine, the targeted water content value of the grains, and the operating modes for grain filling operation, drying operation, etc. Next, explanation is made on the control of the grain filling operation and the control of the drying operation in the circulating type grain drying machine 5 used at the joint-use grain drying and regulating installation 1. The explanation is made for one drying machine 5 representatively and no explanation is repeated for other drying machines 5. First, the explanation is made on the function relating to the introduction, into the circulating type grain drying machine 5, of the grains received at the joint-use grain drying and regulating installation 1. The grains charged at the grain receiving section 2 are forwarded to the horizontal, conveyor 7 through the elevator 8, the rough sorter 3, the scale 4 and the elevator 6. Then, the grains are conveyed to above the drying machine 5 to which the grains are to be introduced. The grains are introduced into the main body 17 of the drying machine from the shutter section 9 which stands—by in an open state. Next, the control of the grain filling operation of the circulating type grain drying machine 5 is explained with reference of the flow-chart in Fig. 5. When the button for grain filling operation of the input section 43 is pressed, the signal is sent therefrom to the arithmetic and control section 42 through the input/output circuit 40. The arithmetic and control section 42 reads out the filling operation program stored in advance in the ROM 43 and starts the execution of the program and controls the subsequent steps (Step S1). Then, the arithmetic and control section 42 starts the operation of the air exhaust means 30, the forwarding valve 14, the screw conveyor 15, the elevator 16 and the scattering plate lla. In this way, the grains introduced into the main body 17 of the drying machine are forwarded downwardly from the forwarding valve 14 for allowing the grains to be circulated within the main body 17 of the drying machine, and the grains are then reintroduced into the main body 17 of the drying machine through the screw conveyor 15, the elevator 16, the selector valve 16b and the circulating pipe 16a. At this time, the selector valve 16b receives a signal from the arithmetic and control section 42 and the flow path has been changed over to the reservoir section 11 side (Step S2). Next, when the grains accumulated in the main body 17 of the drying machine reach the level detector 45 and the presence of the grains is detected by the level detector 45, the arithmetic and control section 42 receives a signal, from the level detector 45 through the input/output circuit 40. Upon receiving this signal, the arithmetic and control section 42 sends a signal to the heating burner section 20 whereby the heating burner 20b starts its operation (at this time, the drying burner section 32 remains in a stopped state) (Step S3}. The temperature of the heated air produced by the heating burner section 20 is detected by the heating pipe temperature sensor 21, and the detected temperature data are inputted into the arithmetic and control section 42 through the A/D converter 41 and the input/output circuit 40 (Step S4). Next, at the Step S5, based on 130°C which is set in advance in the ROM 43 and which is the heated air set tem- perature to be produced at the heating burner section 20 during the grain filling operation, the arithmetic and control section 42 determines whether the temperature of the heated air detected at the above Step S4 is "in accord" with 130°C or not. If in the affirmative, the Step S6 is executed. If the temperature is "out of accord", the Step S5-1 is executed. At the Step S5-1, whether the heated air temperature of the heating burner section 20 is above 130°C is determined. If in the affirmative, the Step S5-1-1 is executed. If the temperature is lower than 130°C , the Step S5-2 is executed. At the Step S5-1-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for decreasing the combustion amount of the heating burner 20b by one level (one step) and, upon receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to decrease the combustion amount of the heating burner 20b by one level. At the Step S5-2, the arithmetic and control section 42 calculates the temperature difference between the detected heated air temperature and 130°C and determines whether such temperature difference is larger than 10°C. If the difference is larger than 10°C, the Step S5-2-1 is executed. Conversely, if the difference is smaller than 10°C, the Step S5-3 is executed. At the Step S5-2-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for increasing the combustion amount of the heating burner 20b by three levels (three steps) and, on receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to increase the combustion amount of the heating burner 20b by three levels. At the Step S5-3, the arithmetic and control section 42 determines whether the above explained temperature difference is larger than 5°C. If the difference is larger than 5°C, the Step S5-3-1 is executed. Conversely, if the difference is smaller than 5°C, the Step S5-4 is executed. At the Step S5-3-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for increasing the combustion amount of the heating burner 20b by two levels (two steps) and, upon receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to decrease the combustion amount of the heating burner 20b by two levels. At the Step S5-4, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for increasing the combustion amount of the heating burner 20b by one level (one step) and, upon receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to increase the combustion amount of the heating burner 20b by one level. After the above Step S5-1-1, Step S5-2-1, Step S5-3-1 and Step S5-4 have been executed, the Step S6 (detection of the outside air humidity) is executed. At the Step S6, the outside air humidity data detected by the outside air humidity sensor 38 are inputted into the arithmetic and control section 42 through the A/D converter 41 and the input/output circuit 40. Next, the arithmetic and control section 42 determines whether the outside air humidity (relative humidity) detected at the Step S6 is larger than 70%. If it is larger than 70%, the Step-S8 is executed and, if it is smaller than 70%, the Step S9 is executed. At the Step S8 (i.e., the outside air humidity being larger than 70%), the arithmetic and control section 42 sends a signal to the exhaust airflow control section 34 for changing the exhaust air amount at the air exhaust means 30 so as to cause the amount of the airflow in the grain flow-down layers 24 to be at a predetermined value. Specifically, where the outside air humidity (relative humidity) is larger than 70% when the airflow aaaount (e.g., 4-5m3/s per 1 ton of grains) of the drying section at the time of the drying operation when the exhaust air amount is not restricted by the exhaust airflow control section 34 is used as reference, the exhaust airflow amount is made 50% with respect to the exhaust airflow amount 100% as at the drying operation so that the airflow may be a first airflow amount (2~2.5m3/s per 1 ton of grains) which is smaller than the reference airflow amount mentioned above. Change in the exhaust airflow amount is effected ±>y the arithmetic and control section 42 which sends a signal to a motor driving circuit 34b for operating the motor 34a and rotating the airflow restricting plate 36 At the Step S9 (i.e., when the outside air humidity is smaller than 70%), the arithmetic and control section 42 sends a signal to the exhaust airflow control section 34 whereby the exhaust airflow amount may be made 30% so that the airflow amount of the heated air at the drying section may be a second airflow amount (1.2-1. 5m3/s per 1 ton of grains) which is smaller than the above-explained first airflow amount. The changing of the exhaust aix amount is effected in the same way as in the Step S8. The outside air humidity 70% has been used as reference for effecting changes in the airflow because, if the grains are exposed to the air having less than 70% of the humidity, the grains become dried. When the dried grains reflux into the drying machine by the elevator 16 and are mixed with the grains newly filled into the drying ma- chine, the grains in the drying machine undergo non- uniform humidity which hinders uniform drying during the drying operation. Thus, in order to prevent the grains from becoming dried, the exhausting air amount is changed by the air exhaust means 30 so that the heated air at the drying section becomes the first airflow amount. On the other hand, if the grains are exposed to the air having more than 70% humidity, the grains are not dried so that, in order to make the heated air at the drying section the second airflow amount, the exhaust air amount is changed by the air exhaust means 30. In the above, the exhaust air amount of the air exhaust means 30 has been restricted to 30% or 50% for the airflow to be predetermined amount, but the exhaust air amount may be set appropriately so that the heated air at the drying section may become the first airflow or the second airflow with the boundary line being 70% of the outside air humidity. The decrease in the airflow amount of the treated air at the drying section is due to the decrease in the suction power of the air exhaust means 30 whose air exhaust amount is lowered by the restriction at the exhaust airflow control section 34. When the stop signal for stopping the grain filling operation is inputted to the arithmetic and control section 42 from the input section 43, the arithmetic and control section 42 automatically stops the operation of the drying machine 5 (Step Sll) and finishes the filling operation program (Step S12). When the stop signal is not inputted, the procedure returns to the Step S4 (Steps S10 through S12). As to the temperature of the heated air produced at the heating burner section 20 for the grain filling operation set in advance in the ROM 43, the temperature is not limited to the above mentioned 130°C and it may be appropriately set. Further, it is possible to arrange that the grain temperature sensor for detecting the temperature of the grains be provided between the heating section and the drying section so that the heating burner section 20 may stop when the grain temperature reaches the predetermined temperature and, when the grain temperature is low, the heating burner section 20 is powered on. According to the above steps, the heated air maintained at 130°C from the heating burner section. 20 passes through within each heating pipe 18 by the suction action of the air exhaust means 30 and, after heating each heating pipe 18 up to a predetermined temperature and after being mixed with the outside air from the outside air intake opening 29 in the leading-in path 28 thus the temperature being lowered, is led into the leading-in path 27. The heated air is also mixed with the outside air sucked into the leading-in path 27 through the outside air intake opening 32c of the drying burner section 32 in a stopped state so that the temperature is further lowered. Further, after being sucked into the air exhaust means 30 through each heated air path 22, each grain flow-down layer 24, each, air exhaust path 23, and the leading-in path 31, the heated air is exhausted through the air exhaust pipe 33 while being restricted by the exhaust airflow control section 34. Thus, when the grains introduced into the main body 17 of the drying machine flow down between the respective heating pipes 18, the grains are heated by heat conduction resulting from being in touch with each heating pipe 18 and by radiant heat from each heating pipe 18 and, while flowing down through each grain flow-down layer 24, the grains are heated but without being dried by the heated air which passes through each grain flow-down layer 24 since such air is of a low temperature and of the airflow adapted to the outside air humidity. In this way, the grains are given preliminary heating during the grain filling operation in advance to the drying operation. Now, hereinafter the drying operation control of the circulating type grain drying machine -5 is explained with reference to the flow charts of Figs. 6(a) and 6(b), Symbols A, B in circles in Fig. 6 (a) are respectively connected to symbols A, B in circles in Fig. 6(b). First, the operator sets and enters from the input section 43 the amount of grains (hereinafter referred to as a "filling amount") to be introduced into and accumulated in the main body 17 of the drying machine, the targeted finishing water content value, etc. This input signal is inputted through the input/output circuit 40 into the arithmetic and control section 42 which stores this input signal in the RAM 46 (Step S1). Next, when the operator presses the button for the drying operation at the input section 43, the relevant signal is sent to the arithmetic and control section 42 through the input/output circuit 40. The arithmetic and control section 42 reads out the drying operation program stored in advance in the ROM 43 and starts the execution of the program. The arithmetic and control section 42 starts the respective operations of the scattering plate Ha, elevator 16, screw conveyor 15, forwarding valve 14, air exhaust means 30, heating burner section 20, and, humidity meter 37. The heating burner section 32 is caused to be operated several minutes later. The exhaust airflow control section 34 is in a full-admission, and the selector valve 16b changes its flow to the main body 17 side (Step S2). Next, the arithmetic and control section 42 enters an initial value at the heated air setting temperature TA for the heating burner section 20, and also enters an initial value at the heated aix setting temperature TB for the drying burner section 32 (Step S3). Next, the humidity meter 37 detects a water content value (water content rate) of the grains supplied to the elevator 16 from the screw conveyor 15 and conveyed upwardly, and the detected values are taken into the arithmetic and control section 42 through the A/D converter 41 and the input/output circuit 40 and, thereafter, are stored in the RAM 46 (Step S4). Then, based on the vater content values of the grains detected in the Step S4, the arithmetic and control section 42 determines the heated air setting temperature TA of the heating burner section 20 at the temperatures as shown in the Table 1. For example, if the water content values of the grains are within the range of 21-25%, the heated air setting temperature TA is set to 130°C and, if the Jirater content values of the grains are within the range of 19-21%, the heated air setting temperature TA is set to 120°C (Step S5). Then, based on the water content values in Step S4 and the filling amount stored in the RAM 46 in the Step S1, the arithmetic and control section 42 determines the setting temperature TB of the heated air supplied to each heated air path at the temperatures as shown in the Table 1. For example, if the water content values of the grains are within the range of 21-25% and the filling amount is at the level "6", the heated air setting temperature TB is set to 39°C and, if the water content values of the grains are within the range of 19-21% and moreover the filling amount is at the level "6", the heated air setting temperature TB is set to 38°C (Step S6). Then, the heated air temperature of the heating burner section 20 is detected by the heating pipe temperature sensor 21, and the detected temperature data are entered into the arithmetic and control section 42 through the A/D converter 41 and the input/output circuit 40. Next, the arithmetic and control section 42 determines whether the heated air temperature of: the heating burner section 20 is "in accord" with the heating air setting temperature TA set in advance. If the result is "out of accord", the Step S8-1 is executed and, if the result is "in accord", the Step S9 is executed (Step S8). At the Step S8-1, the determination is made as to whether the heated air from the heating burner section 20 is higher than the heated air setting temperature TA- If the heated air temperature is higher than the heated air setting temperature TA, the Step S8-1-1 is executed and, if the heated air temperature is lower than TA, the Step S8-2 is executed. At the Step S8-1-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for decreasing the combustion amount of the heating burner 20b by one level (one step) and, upon receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to decrease the combustion amount of the heating burner 20b by one level. At the Step S8-5, the arithmetic and control section 42 calculates the temperature difference between the detected heated air temperature and the heated air setting temperature TA and determines whether such temperature difference is larger than 10°C. If the difference is larger than 10°C, the Step S8-2-1 is executed. Conversely, if the difference is smaller than 10°C, the Step S8-3 is executed. At the Step S8-2-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for increasing the combustion amount of the heating burner 20b by three levels (three steps) and, on receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to increase the combustion amount of the heating burner 20b by three levels. At the Step S8-3, the arithmetic and control section 42 determines whether the temperature difference is larger than 5°C. If the difference is larger than 5°C, the Step S8-3-1 is executed. Conversely, if the difference is smaller than 5°C, the Step S8-4 is executed. At the Step S8-3-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for increasing the combustion amount of the heating burner 20b by two levels (two steps) and, upon receiving this signal, the fuel adjusting circuit 20a causes the heating- burner 20b to increase the combustion amount of the heating burner 20b by two levels. At the Step S8-4, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 20a for increasing the combustion amount of the heating burner 20b by one level (one step) and, upon receiving this signal, the fuel adjusting circuit 20a causes the heating burner 20b to increase the combustion amount of the heating burner 20b by one level. After the above Step S8-1-1, Step S8-2-1, Step S8-3-1 and Step S8-4 have been executed, the Step S9 (measurement of the heated air temperature of the heated air path) is executed. At the Step S9, the heated air temperature of the drying burner section 32 is detected by the drying section temperature sensor 26, and the detected temperature data are inputted into the arithmetic and control section 42 through the A/D converter 41 and the input/output circuit 40. Next, the arithmetic and control section 42 determines whether the water content values of the grains detected by the Step S4 is smaller than 20%. If it is not smaller than 20%, the Step Sll is executed and, if it is smaller than 20%, the Step S10-1 is executed (Step S10). At the Step S10-1, the arithmetic and control section 42 calculates, based on the water content value stored in the RAM 46, the difference in the water content value as of the time after the lapse of a predetermined time, and derives a value (drying speed value) by dividing the cal- culated difference in the water content value by such predetermined time, and further multiplying by 60. Next, at the Step S10-2, it is determined whether such drying speed value corresponds to any of the classes of the drying speed values set and stored in advance in the ROM 43. The arithmetic and control section 42 changes the setting of the heated air setting temperature TB of the heated air path 22 based on the heated air temperature compensation values of the heated air path 22 set correspondingly to the respective classes and stored in advance in the ROM 43. Next, at the Step Sll, the arithmetic and control section 42 determines whether the heated air temperature of the heated air path 22 is "in accord" with the heating air setting temperature TB set in advance. If the result is "out of accord", the Step Sll-1 is executed and, if the result is "in accord", the Step S12 is executed. At the Step Sll-1, the determination is made as to whether the heated air xrf the heated air path 22 is larger than the heated air setting temperature TB. If the heated air temperature is larger than the heated air setting temperature TB, the Step S11-1-1 is executed and, if the heated air temperature is smaller than TB, the Step Sll-2 is executed. At the Step Sll-1-1, the arithmetic and control sec- tion 42 sends a signal to the fuel adjusting circuit 32a for decreasing the combustion amount of the drying burner 32b by one level (one step) and/ upon receiving this signal, the fuel adjusting circuit 32a causes the drying burner 32b to decrease the combustion amount of the drying burner 32b by one level. At the Step Sll-2, the arithmetic and control section 42 calculates the temperature difference between the detected heated air temperature and the heated air setting temperature TB and determines whether such temperature difference is larger than 10°C. If the difference is larger than 10°C, the Step Sll-2-1 is executed. Conversely, if the difference is smaller than 10°C, the Step Sll-3 is executed. At the Step Sll-2-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 32a for increasing the combustion amount of the drying burner 32b by three levels (three steps) and, on receiving this signal, the fuel adjusting circuit 32a causes the drying burner 32b to increase the combustion amount of the drying burner 32b by three Levels. At the Step Sll-3, the arithmetic and control section 42 determines whether the temperature difference is larger than 5°C. If the difference is larger than 5°C, the Step S11-3-1 is executed. Conversely, if the difference is smaller than 5°C, the Step Sll-4 is executed. At the Step Sll-3-1, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 32a fox increasing the combustion amount of the drying burner 32b by two levels (two steps) and, upon receiving this signal, the fuel adjusting circuit 32a causes the drying burner 32b to increase the combustion amount of the drying burner 32b by two levels. At the Step Sll-4, the arithmetic and control section 42 sends a signal to the fuel adjusting circuit 32a for increasing the combustion amount of the drying burner 32b by pne level (one step) and, upon receiving this signal, the fuel adjusting circuit 32a causes the drying burner 32b to increase the combustion amount of the drying burner 32b by one level. After the above Step Sll-1-1, Step Sll-2-1, Step Sll- 3-1 and Step S11—4 have been executed, the Step S12 is executed. Next, at the Step S12, the arithmetic and control section 42 determines whether the water content value measured at the Step S4 is below the targeted finishing water content value eatered at the Step S1. If the water content value is below the targeted finishing water content value, the Step S13 is executed and, if not below, the procedure returns to the Step S4. At the Steps S13 and S14, the arithmetic and control section 42 ends the drying operation program after causing the drying machine 5 to stop automatically. By the drying operation control in the Steps S1 through S14, the heating section 12 of the circulating type grain drying machine 5 of the present invention maintains the temperature of the heated air supplied to each heating pipe 18 to the temperature adapted to the water content value of the grain, thus enabling to effect a preliminary heating by each heating section 12 heated by the heated air of the above temperature. On the other hand, the drying section 13 maintains the heated air supplied to each heated air path 22 at the temperature adapted to the water content value of the grain and the filling amount, and the drying can be carried out by the heated air (drying air) of the above temperature. Thus, the time required for the drying of the grains can be reduced from that conventionally required. In order to solve the first technical problem, according to the circulating type grain drying machine, the control means causes the first heated air generating means to operate and the second heated air generating means to stop. The control means sends a signal to the exhaust airflow control section according to the outside air humidity detected by the outside air humidity detection means and, by the operation of the exhaust airflow control section, the exhaust airflow from the air exhaust means is caused to be changed and the airflow in the drying section is changed. Thus, each heating pipe is heated by the heated air of the first heated air generating means, and the heated air turns to low temperature resulting from the mixing with the outside air introduced through the second heated air generating means which is in a stopped state, and the low temperature heated air is introduced into the drying section. Since the amount of the exhaust air from the air exhaust means is changed by the exhaust airflow control section operated according to the outside air humidity, the airflow of the low temperature heated air introduced into the drying section is changed according to the outside humidity. Thus, while flowing down between the heating pipes, the grains introduced into the drying machine are heated by the heart conduction caused by being in contact with each heating pipe and by radiating heat of each heating pipe and, while flowing down through each grain flow-down layer, the grains are exposed to the heated air which is of a low temperature, which passes through each grain flow-down layer and the airflow of which is adapted to the outside humidity, the grains are heated without being dried. Thus, it is possible to effect the preliminary heating of the grains during the grain filling preliminary heated by each heating pipe heated by the temperature which is varied as the drying progresses and which is adapted to the water content of the grains. The preliminarily heated grains flow down into the drying section and, at the drying section, the heated air of the temperature adapted to the grain water content value and to the filling amount, thereby enabling the efficient drying operation and also enabling the reduction in the drying time as compared with that in the conventional machine. While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description rather than limitation and that changes within the purview of the appended claims may be made without departing from the true scope of the invention as defined by the claims. WE CLAIM 1. A circulating type grain drying machine comprising: a heating section for heating grains equipped with a plurality of heating pipes through which heated air from a first heated air generating means passes; a drying section arranged under said heating section, for drying grains by supplying heated air having passed through each heating pipe together with heated air from a second heated air generating means; an air exhaust means for sucking the heated air of said drying section and exhausting said heated air to outside the drying machine; an exhaust airflow control section for controlling the amount of exhaust air of said air exhaust means; an outside air humidity detection means for detecting an outside air humidity; and a control means electrically connected to each of said first heated air generating means, said second heated air generating means, said exhaust airflow control section, and said outside air humidity detection means, said coatrol means causing, during the grain filling operation, said first heated air generating means to operate and at the same time said second heated air generating means to stop to operate, and said exhaust airflow control section to operate according to the detected outside air humidity value detected by said outside air humidity de tection means and to change the exhaust airflow of said air exhaust means. 2. A circulating type grain drying machine as claimed in claim 1, in which the airflow of said drying section during the drying operation when the exhaust airflow is not restricted by said exhaust airflow control section is used as reference and, if the outside air humidity value is above a predetermined humidity, the airflow of the air in said drying section is caused to be a first airflow which is smaller than said reference and, if the outside air humidity value is below the predetermined value, the airflow of the air in said drying section is caused to be a second airflow which is even smaller than said first airflow and, by the operation of said exhaust airflow control section, the exhaust airflow of said air exhaust means is caused to be changed. 3. A circulating type grain drying machine as claimed in claim 2, in which said predetermined humidity is 70%. 4. A circulating type grain drying machine comprising: a heating section for heating grains equipped with a plurality of heating pipes through which heated air from a first heated air generating means passes; a drying section arranged under said heating section, for drying grains by supplying heated air having passed through each heating pipe together with heated air from a second heated air generating means; an air exhaust means for sucking the heated air of said drying section and exhausting the heated air to outside the drying machine; a drying heated air temperature detecting means for detecting a temperature of the heated air supplied to said drying section; a heating pipe heated air temperature detecting means for detecting a temperature of the heated air supplied to said heating pipes; a water content detecting means for detecting water content values of grains; an inpat section for inputting the amount of filled grains; and a control means electrically connected to each of said first heated air generating means, said second heated air generating, means, said drying heated air temperature detecting means, said heating pipe heated air temperature detecting means, said water content detecting means and said input section, said control means controlling, during the drying operation, said first heated air generating means to change the temperature of the heated air supplied into each heating pipe according to the detected value of water content of the grains, and said second heated air generating means to change the temperature of the heated air supplied into said drying section according to the detected value of water content of the grains and the value of filled grains. The circulating type grain drying machine is provided in which, at the grain filling operation, a controller (39) causes a first heated air generator (20) to operate and a second heated air generator (32) to stop operating, and also causes, according to the detected values of the outside air humidity from an outside air humidity detector (38), an airflow control section (34) to operate so as to change the quantity of the airflow by an air exhaust section. Also, at the drying operation, the controller controls the first heated air generator (20) and controls the temperature of the heated air supplied Into each heating pipe (18) according to the detected values of the grain water content value, and controls the temperature of the temperature of the heated air supplied Into the drying section (32) according to the detected values of the grain water content values and the grain filling amount.

Full Text

CIRCULATING TYPE GRAIN DRYING MACHINE
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a. circulating type
grain drying machine for drying grains, for example, an
unhulled rice, wheat, etc.
(2) Description of the Related Art
Conventionally, there is a circulating type grain
drying machine in which, for reducing the time required
for drying, separately from a drying section for drying
grains with heated air being supplied, there is provided a
heating section for preliminarily increasing the temperature
of grains (hereinafter referred to as a -"grain
temperature").
For example, Japanese Patent Application Kokai Publication
No. Sho 62-9174 discloses a circulating type grain
drying machine for providing preliminary heating to
grains, which is provided, sequentially from the top
thereof, with a reservoir section for temporarily keeping
grains, a heating section having a plurality of heating
pipes through which the heated air generated by one burner
passes, and a drying section for drying the grains by
heated air introduced from each of the heating pipes.
Also, Japanese Patent Application Kokai Publication
No. Hei 2-309122-discloses a machine which is provided,
sequentially from the top thereof, with a reservoir section,
an upper drying section for effecting preliminary
heating of grains equipped with a first burner, and a lower
drying section for drying the grains also equipped with
a second burner.
Further, Japanese Patent Application No. Hei 10-
265486 in which the applicant is the same as in the present
application discloses a machine which is provided,
sequentially from the top thereof, with a reservoir section,
a heating section for effecting preliminary heating
of grains equipped with a plurality of heating pipes
through which the heated air produced by a heating means
passes, and a- drying section for drying the grains by the
heated -air produced by a heating means provided separately
from the above heating means.
In the above respective conventional circulating type
grain drying machines, there are respectively the following
problems:
With respect to the conventional machine disclosed in
Japanese Patent Application Kokai Publication No. Sho 62-
9174, the heated air generated by one burner passes
through and heats each heating pipe and the heated air,
after the heat is taken by the heating pipes with the
heated air resulting in a lower temperature, is introduced
into the drying section and serves as the heated air again
for drying the grains. In order to introduce heated air of
a predetermined temperature into the drying section, it is
necessary to raise, according to the predetermined temperature,
the temperature of the heated air for heating
the heating pipes. Hence, in the disclosed machine, the
heating pipes cannot be heated sufficiently. Also, since
the heating temperature of the heating pipes and the
heated air temperature of the drying section cannot be
controlled separately, a drying efficiency may not be
satisfactory.
In the conventional machine disclosed in Japanese
Patent Application Kokai Publication No. Hei 2-309177, the
drying is carried out by supplying to the grains in the
upper drying section the heated air of high temperature
and of small amount of airflow and, after the grain temperature
has been raised, the grains are then subjected to
the heated air of low temperature and of large amount of
airflow in the lower drying section. Since the grains are
exposed to the heated air for a long time at both the upper
and lower drying sections, the quality of the grains
will be afected and aggravated. Also, since the upper
drying section and the lower drying section are provided
respectively with separate burners, the quality deterioration
of grains as mentioned above is caused thereby and,
since the heated air at the upper drying section is not
utilized in the lower drying section, the drying efficiency
will not be satisfactory and the improvement is
desired.
In the machine disclosed in Japanese Patent Application
No. Hei 10-265486, the heating section and the drying
section are respectively provided with heating means. After
the grains are subjected to a preliminary heating
through the heating pipes heated up to a predetermined
temperature by the heating means of the heating section,
the heated air which is produced separately from the above
heating means and which is lower than the grain temperature
is supplied to the grains in the drying section
whereby the grains are efficiently dried while the quality
deterioration is being prevented. However, in this drying
machine, the heating temperature of the heating pipes is
set to a predetermined constant temperature, and the heated
air supplied to the drying section is made lower than
only the grain temperature produced by the heating
section. Thus, the arrangement was not one in which, in
consideration of the grain water content which varies as
the drying operation progresses, the heatings temperature
of the heating pipes and the heated air temperature supplied
to the drying section are respectively controlled to
optimum temperatures. Also, the heating section and the
drying section are provided with separate heating means,
and the heated air of the heating section is simply exhausted
to outside the drying machine. Thus, the improvement
is desired in the aspect of the drying efficiency.
SUMMARY OF THE INVENTION
In view of the problems in the conventional circulating
type grain drying machines explained above and in order
to further reduce the drying time and to enhance the
drying efficiency, the inventors of the present invention
aim at providing an improved circulating type drying machine
with which the drying time is reduced and in which
the first object is to enable the preliminary heating of
the grains starting from the time of the grain filling
operation, and the second object is to enable the separate
controlling of the heated air temperature of the heating
section and the heated air temperature of the drying section
in accordance with the grain water content values
during the drying operation while utilizing the heated air
of the heating section.
According to one aspect of the inVention, there is
provided a circulating type grain drying machine, comprising:
a heating section for heating grains equipped with a
plurality of heating pipes through which heated air from a
first: heated air generating means passes;
a drying section under the heating section, for drying
grains by supplying heated air having passed through
each heating pipe together with heated air from a second
heated air generating means;
an air exhaust means for sucking the heated air of
the drying section and exhausting the heated air to outside
the drying machine;
an exhaust airflow control section for controlling
the amount of exhaust air of the air exhaust means;
an outside air humidity detection means for detecting
an outside air humidity; and
a control means electrically connected to each of the
first heated air generating means, the second heated air
generating means, the exhaust airflow control section, and
the outside air humidity detection means,
the control means causing, during the grain filling
operation, the first heated air generating means to operate
and at the same time the second heated air generating
means to stop to operate, and the exhaust airflow control
section to operate according to the detected outside air
humidity value detected by the outside air humidity detection
means and to change the exhaust airflow of the air
exhaust means.
The control means causes the first heated air gener-
ating means to operate and the second heated air generating
means to stop. The control means sends a signal to the
exhaust airflow control section operative according to the
outside air humidity detected by the outside air humidity
detection means and, by the operation of the exhaust airflow
control section, the exhaust airflow from the air
exhaust means is caused to be changed and the airflow in
the drying section is changed. Thus, each heating pipe is
heated by the heated air of the first heated air generating
means, and the heated air turns to a low temperature
resulting from the mixing with the outside air introduced
through the second heated air generating means which is in
a stopped state, and the low temperature heated air is
introduced into the drying section. Since the amount of
the exhaust air from the air exhaust means is changed by
the exhaust airflow control- section operated according to
the outside air humadity, the airflow of the low temperature
heated air introduced into the drying section is
changed according to the outside humidity. Thus, while
flowing down between the heating pipes, the grains introduced
into the drying machine are heated by the heat, conduction
caused by being in contact with each heating pipe
and by radiating heat of each heating pipe and, while
flowing down through each grain flow-down layer, the
grains are exposed to the heated air which is of a low
temperature, which passes through each grain flow-down
layer and the airflow of which is adapted to the outside
humidity, the grains are heated without beings dried. Thus,
it is possible to effect the preliminary heating of the
grains during the grain filling operation in advance to
the drying operation.
If the grains are dried during the grain filling operation
and such grains are mixed with the grains filled
in the drying machine, there develops an uneven humidity
state in the grains within the drying machine, which is
unfavorable as it causes the grains to be unevenly dried
during the subsequent drying operation.
The above circulating type grain drying machine is
arranged such that the airflow of the drying section during
the drying operation when the exhaust airflow is not
restricted by the exhaust airflow control section is used
as reference and, if the outside air humidity value is
above a predetermined humidity, the airflow of the air in
the drying section is caused to be a first airflow which
is smaller than the reference and, if the outside air humidity
value is below the predetermined value, the airflow
of the air in the drying section is caused to be a second
airflow which is even smaller than the first airflow
and, by the operation of the exhaust airflow control
section, the exhaust airflow of the air exhaust means is
caused to be changed.
Thus, by using the airflow in the drying section when
the exhaust airflow is not restricted by the exhaust airflow
control section as reference, the drying machine operates
with the airflow of the drying section as the first
airflow which is smaller than the reference and, when the
humidity is below the predetermined humidity, operates
with the airflow as the second airflow which is smaller
than the first airflow, and the grains in the drying section
are exposed to the airflow which is adapted to the
outside humidity and to the heated air of a low temperature.
Thus, the grains are heated without being dried at
the drying section.
In the circulating type grain drying machine, it is
preferable that the predetermined humidity is set to 70%.
Thus, the airflow in the drying section changes with
the outside air humidity of 70% as the boundary line, the
grains are heated without being dried.
According to another aspect of the invention/ there
is provided a circulating type grain drying machine, comprising:
a heating section for heating grains, equipped with a
plurality of heating pipes through which heated air from a
first heated air generating means passes;
a drying section under the heating section, for dry-
ing grains by supplying heated air having passed through
each heating pipe together with heated air from a second
heated air generating means;
an air exhaust means for sucking the heated air of
the drying section and exhausting the heated air to outside
the drying machine;
a drying -heated air temperature detecting means for
detecting a temperature of the heated air supplied to the
drying section;
a heating pipe heated air temperature detecting means
for detecting a temperature of the heated air supplied to
the heating pipes;
a water content detecting means for detecting water
content values of grains;
an input section for inputting the amount of filled
grains; and
a control means electrically connected to each of the
first heated air generating means, the second heated air.
generating means, the drying heated air temperature detecting
means, the heating pipe heated air temperature
detecting means, the water content detecting means and the
input section,
the control means controlling, during the drying operation,
the first heated air generating means to change
the temperature of the heated air supplied into each heat-
ing pipe according to the detected value of water content
of the grains, and the second heated air generating means
to change the temperature of the heated air supplied into
the drying section according to the detected value of water
content of the grains and the value of filled grains.
The control means controls the first heated air generating
means based on the detected temperature value by
the heating pipe heated air temperature detecting means so
that the heated air supplied to the heating pipes becomes
the temperature adapted to the grain water content value,
the heating temperature of each heating pipe becomes the
temperature adapted to the water content values of the
grains. On the other handr since the control means controls
the second heated air generating means based on the
detected heated air temperature value detected by the drying
heated air temperature detecting means so that the
heated air supplied to the drying section becomes the temperature
adapted to the grain water content value and the
grain filling amount, the heated air introduced into the
drying section and passed through each heating pipe is
mixed with the outside air in-taken from the outside air
in—taking opening and becomes the temperature adapted to
the water content values and the grain filling amount.
Further, the heating temperature of each heating pipe and
the heated air temperature of the drying section are of
temperatures which do not cause the deterioration of the
grains such as by cracks. Thus, the gxairus filled in the
drying machine are preliminary heated by each heating pipe
heated by the temperature which is varied as the drying
progresses and which is adapted to the water content of
the grains. The preliminarily heated grains flow down into
the drying section and, at the drying section, the heated
air of the temperature adapted to the grain water content
value and to the grain filling amount, thereby enabling
the efficient drying operation and also enabling the re-
duction in the drying time as compared with that in the
conventional machine.
BRIEF DESCRIPTION OF THE^PRAWINGS ° 0 -
The above and other objects, features and advantages
of the present invention, will be apparent from the follow-
ing description of preferred embodiments of the invention
explained with reference to the accompanying drawings, in
which:
Fig. 1 is a view showing main elements of one example
of a joint-use grain drying and regulating installation
according to the invention;
Fig. 2 is a front view showing a circulating type
grain drying machine, partially in section, according to
the invention;
Fig. 3 is a side view showing a circulating type grain
drying machine, partially in section,, according to the
invention;
Fig. 4 is a control block diagram for controlling a
circulating type grain drying machine according to the
invention;
Fig. 5 is a flow chart of grain filling operation and
controlling of a circulating type grain drying machine
according to the invention; and
Figs. 6(a) and 6(b) are flow charts of drying operation
and controlling of a circulating type grain drying
machine according to the invention.
PREFERRED EMBODIMENTS OF THE INVENTION
With reference to Figs. 1-6, hereinafter explained
are a construction of one exemplified joint-use grain drying
and regulating installation, a configuration of a circulating
type grain drying machine used in the installation,
a method of grain filling and controlling operations,
and a method of drying and controlling operations.
First, Fig. 1 shows main elements of the above mentioned
joint-use grain drying and regulating installation.
The joint-use grain drying and regulating installation
1 is equipped with a grain receiving section 2, a
rough sorter 3, a scale 4, a plurality of circulating type
drying machines 5, a hull removing/fine sorting section
(not shown), a silo (not shown) and an air exhaust means.
The grain receiving section 2 is communicated to the rough
sorter 3 through an elevator 8. The rough sorter 3 is communicated
to the scale 4 arranged under the rough sorter
3. The scale 4 is communicated to a horizontal conveyor 7
provided over each drying machine 5 through an elevator 6.
The horizontal conveyor 7 is provided with, at a location
of each drying machine, a shutter section 9 which is used
when the grains are supplied into each drying machine 5.
Each shutter section 9 and an upper portion of each drying
maehine 5 are communicated with each other through a feeding
pipe 10.
Next, structural arrangements of the circulating type
drying machine 5 are explained with reference to Figs. 2
and 3. Fig. 2 is a front view, partially in section, of
the machine, and Fig. 3 is a side view, also partially in
section, of the machine. Here one representative drying
machine 5 is explained. The drying machine 5 is provided
with, sequentially from the top thereof, a reservoir section
11 for storing grains, a heating section 12 for providing
preliminary heating to the grains, a drying section
13 for drying the grains by heating air, a forwarding
valve 14 for forwarding the grains, and a screw conveyor
15 for discharging the grains to the conveying starting
end at a lower portion of the elevator 16 explained later.
The heating section 12 is provided with a plurality
of heating pipes 18 upper and lower ones of which are
horizontally provided in a staggered form. On the other
hand, at one side 17a of the body 17 of the drying machine,
there is provided a first heated air generating
means 20 (hereinafter referred to as a "heating burner
section") which is communicated to the heated air supplying
side of each heating pipe 18 through a leading-in path
19. Within the leading-in path 19, there is provided a
heating pipe temperature sensor 21 for detecting the temperature
of the heated air supplied to each heating pipe
18. Further, the heating burner section 20 is equipped
with the heating burner 20b which uses kerosene as fuel,
and with a fuel adjusting circuit 20a which adjusts the
amount of fuel supplied to the heating burner 20b. Also,
between the lower level heating pipes 18, 18 opposing with
each other, there is provided a level, detector 45 which
detects presence or non-presence of the grains.
The drying section 13 has a plurality of heated air
paths 22 and a plurality of air exhaust paths 23. The
heated air paths 22 and the air exhaust paths 23 are alternately
provided in a row. The side surfaces of the
heated air paths 22 and the air exhaust paths 23 are respectively
formed by perforated plates so that the heated
air is allowed to pass therethrough, and there is a grain
flow-down layer 24 between the adjacent ones of the heated
air paths 22 and the air exhaust paths 23. At an upper
portion of the heated air leading-in side of the heated
air path 22, there is provided a drying section temperature
sensor 26 for detecting the temperature of the heated
air. At the other side 17b of the main body 17 of the dry-
ing machine, there is provided a second heated air generating
means 32 (hereinafter referred to as a "drying
burner section") which communicates with the heated air
supplying section of each of the heated air paths 22
through a leading-in path 27. Further, the drying burner
section 32 is equipped with a drying burner 32b which uses
kerosene as fuel and with a fuel amount adjusting circuit
32a for adjusting the amount of the fuel supplied to the
drying burner 32b.
The exhaust side of the heated air of each heating
pipe 18 is communicated through the leading-in path 28 so
that the heated air passing through each of the heating
pipe 18 is led-in the leading-in path 27, and the leading-
in path 28 is equipped with an outside air taking-in opening
29 for taking-in the outside air. On one hand, at the
one side 17a of the main body 17 of the drying machine,
there is provided an. air exhaust means 30. The air exhaust
means 30 communicates with the heated air exhausting side
of each of the air exhaust paths 23 through a leading-in
path 31. The air exhaust means 30 is connected through an
air exhaust pipe 33 to an exhaust air treating means (not
shown) for treating the exhaust air containing dust. In
the vicinity of a location at which the exhaust pipe 33
and the air exhaust mean 30 are connected with each other,
there is provided an exhaust airflow control section 34.
The exhaust airflow control section 34, in this preferred
embodiment, is provided with an airflow restricting plate
36 which rotates around a shaft 35, a motor 34a which rotates
the shaft -35 and a motor driving circuit 34b.
A plurality of forwarding valves 14 are provided with
each of them being in a corresponding relation with respect
to each of the grain flow-down layers 24. Below each
of the plurality of forwarding valves 14, there is provided
a screw conveyor 15.
The elevator 16 stands at the side of the main body
17 of each drying machine 5. The elevator 16 is communicated
with the discharging side of the screw conveyor 15
at the conveying starting end side at the lower portion,
and the conveying finishing end side at the upper portion
is communicated with the reservoir section 11 through a
circulating pipe 16a. The circulating pipe 16a is equipped
with a bi-directional valve, that is, a selector valve 16b
which enables the selection either to the reservoir sec-
tion 11 side or to the horizontal conveying machine 7
side. The horizontal conveying machine 1 side of the selector
valve 16b is communicated with the horizontal conveying
machine 7 through a pipe 16c. Further, at the lower
portion of each elevator 16, there is provided a humidity
meter 37 for detecting the moisture content (water content
value) of the grain which is taken from within the elevator
16.
Under the circulating pipe 16a and the feeding pipe
10 at the inner side of the ceiling of the main body 17 of
the drying machine, there is provided a scattering plate
lla for scattering the grains supplied from each of the
pipes 16a, 10. Also, at the air in-taking side of the drying
burner section 32, there is provided an outside air
humidity sensor 38 for detecting the humidity of the outside
air.
Next, the configuration of the control means 39 of
the circulating type drying machine 5 described above is
explained with reference mainly to Fig. 4. The control
means 39 has an arithmetic and control section 42 having
CPU as its central or main component, and electrically
connected to the arithmetic and control section 42 are an
input/output circuit 40, a ROM 43 (read-only memory) for
storing data, program, etc. and a RAM 46 (random access
memory) for storing data. The input/output circuit 40 is
electrically connected, through an A/D converter 41 for
converting ah analog signal to a digital signal, to respectively
the heated air pipe temperature sensor 21, the
drying section temperature sensor 26, the outside air humidity
sensor 38 and the humidity meter 37. Also, the input/output
circuit 40 is electrically connected to respectively
the input section 43, the heating burner section
20, the drying burner section 32, the level detector 45,
the exhaust airflow control section 34, the air exhaust
means 30, the elevator 16 and the selector valve 16b. The
input section 43 selects and sets the quantity of the
grains to be introduced (filling amount or quantity) into
the main body 17 of the drying machine, the targeted water
content value of the grains, and the operating modes for
grain filling operation, drying operation, etc.
Next, explanation is made on the control of the grain
filling operation and the control of the drying operation
in the circulating type grain drying machine 5 used at the
joint-use grain drying and regulating installation 1. The
explanation is made for one drying machine 5 representatively
and no explanation is repeated for other drying
machines 5.
First, the explanation is made on the function relating
to the introduction, into the circulating type grain
drying machine 5, of the grains received at the joint-use
grain drying and regulating installation 1. The grains
charged at the grain receiving section 2 are forwarded to
the horizontal, conveyor 7 through the elevator 8, the
rough sorter 3, the scale 4 and the elevator 6. Then, the
grains are conveyed to above the drying machine 5 to which
the grains are to be introduced. The grains are introduced
into the main body 17 of the drying machine from the shutter
section 9 which stands—by in an open state.
Next, the control of the grain filling operation of
the circulating type grain drying machine 5 is explained
with reference of the flow-chart in Fig. 5. When the button
for grain filling operation of the input section 43 is
pressed, the signal is sent therefrom to the arithmetic
and control section 42 through the input/output circuit
40. The arithmetic and control section 42 reads out the
filling operation program stored in advance in the ROM 43
and starts the execution of the program and controls the
subsequent steps (Step S1).
Then, the arithmetic and control section 42 starts
the operation of the air exhaust means 30, the forwarding
valve 14, the screw conveyor 15, the elevator 16 and the
scattering plate lla. In this way, the grains introduced
into the main body 17 of the drying machine are forwarded
downwardly from the forwarding valve 14 for allowing the
grains to be circulated within the main body 17 of the
drying machine, and the grains are then reintroduced into
the main body 17 of the drying machine through the screw
conveyor 15, the elevator 16, the selector valve 16b and
the circulating pipe 16a. At this time, the selector valve
16b receives a signal from the arithmetic and control section
42 and the flow path has been changed over to the
reservoir section 11 side (Step S2).
Next, when the grains accumulated in the main body 17
of the drying machine reach the level detector 45 and the
presence of the grains is detected by the level detector
45, the arithmetic and control section 42 receives a signal,
from the level detector 45 through the input/output
circuit 40. Upon receiving this signal, the arithmetic and
control section 42 sends a signal to the heating burner
section 20 whereby the heating burner 20b starts its operation
(at this time, the drying burner section 32 remains
in a stopped state) (Step S3}.
The temperature of the heated air produced by the
heating burner section 20 is detected by the heating pipe
temperature sensor 21, and the detected temperature data
are inputted into the arithmetic and control section 42
through the A/D converter 41 and the input/output circuit
40 (Step S4).
Next, at the Step S5, based on 130°C which is set in
advance in the ROM 43 and which is the heated air set tem-
perature to be produced at the heating burner section 20
during the grain filling operation, the arithmetic and
control section 42 determines whether the temperature of
the heated air detected at the above Step S4 is "in accord"
with 130°C or not. If in the affirmative, the Step
S6 is executed. If the temperature is "out of accord", the
Step S5-1 is executed.
At the Step S5-1, whether the heated air temperature
of the heating burner section 20 is above 130°C is determined.
If in the affirmative, the Step S5-1-1 is executed.
If the temperature is lower than 130°C , the Step S5-2 is
executed.
At the Step S5-1-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a
for decreasing the combustion amount of the heating burner
20b by one level (one step) and, upon receiving this signal,
the fuel adjusting circuit 20a causes the heating
burner 20b to decrease the combustion amount of the heating
burner 20b by one level.
At the Step S5-2, the arithmetic and control section
42 calculates the temperature difference between the detected
heated air temperature and 130°C and determines
whether such temperature difference is larger than 10°C.
If the difference is larger than 10°C, the Step S5-2-1 is
executed. Conversely, if the difference is smaller than
10°C, the Step S5-3 is executed.
At the Step S5-2-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a
for increasing the combustion amount of the heating burner
20b by three levels (three steps) and, on receiving this
signal, the fuel adjusting circuit 20a causes the heating
burner 20b to increase the combustion amount of the heating
burner 20b by three levels.
At the Step S5-3, the arithmetic and control section
42 determines whether the above explained temperature difference
is larger than 5°C. If the difference is larger
than 5°C, the Step S5-3-1 is executed. Conversely, if the
difference is smaller than 5°C, the Step S5-4 is executed.
At the Step S5-3-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a
for increasing the combustion amount of the heating burner
20b by two levels (two steps) and, upon receiving this
signal, the fuel adjusting circuit 20a causes the heating
burner 20b to decrease the combustion amount of the heating
burner 20b by two levels.
At the Step S5-4, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a for
increasing the combustion amount of the heating burner 20b
by one level (one step) and, upon receiving this signal,
the fuel adjusting circuit 20a causes the heating burner
20b to increase the combustion amount of the heating
burner 20b by one level.
After the above Step S5-1-1, Step S5-2-1, Step S5-3-1
and Step S5-4 have been executed, the Step S6 (detection
of the outside air humidity) is executed.
At the Step S6, the outside air humidity data detected
by the outside air humidity sensor 38 are inputted
into the arithmetic and control section 42 through the A/D
converter 41 and the input/output circuit 40.
Next, the arithmetic and control section 42 determines
whether the outside air humidity (relative humidity)
detected at the Step S6 is larger than 70%. If it is larger
than 70%, the Step-S8 is executed and, if it is
smaller than 70%, the Step S9 is executed.
At the Step S8 (i.e., the outside air humidity being
larger than 70%), the arithmetic and control section 42
sends a signal to the exhaust airflow control section 34
for changing the exhaust air amount at the air exhaust
means 30 so as to cause the amount of the airflow in the
grain flow-down layers 24 to be at a predetermined value.
Specifically, where the outside air humidity (relative
humidity) is larger than 70% when the airflow aaaount
(e.g., 4-5m3/s per 1 ton of grains) of the drying section
at the time of the drying operation when the exhaust air
amount is not restricted by the exhaust airflow control
section 34 is used as reference, the exhaust airflow
amount is made 50% with respect to the exhaust airflow
amount 100% as at the drying operation so that the airflow
may be a first airflow amount (2~2.5m3/s per 1 ton of
grains) which is smaller than the reference airflow amount
mentioned above. Change in the exhaust airflow amount is
effected ±>y the arithmetic and control section 42 which
sends a signal to a motor driving circuit 34b for operating
the motor 34a and rotating the airflow restricting
plate 36
At the Step S9 (i.e., when the outside air humidity
is smaller than 70%), the arithmetic and control section
42 sends a signal to the exhaust airflow control section
34 whereby the exhaust airflow amount may be made 30% so
that the airflow amount of the heated air at the drying
section may be a second airflow amount (1.2-1. 5m3/s per 1
ton of grains) which is smaller than the above-explained
first airflow amount. The changing of the exhaust aix
amount is effected in the same way as in the Step S8.
The outside air humidity 70% has been used as reference
for effecting changes in the airflow because, if the
grains are exposed to the air having less than 70% of the
humidity, the grains become dried. When the dried grains
reflux into the drying machine by the elevator 16 and are
mixed with the grains newly filled into the drying ma-
chine, the grains in the drying machine undergo non-
uniform humidity which hinders uniform drying during the
drying operation. Thus, in order to prevent the grains
from becoming dried, the exhausting air amount is changed
by the air exhaust means 30 so that the heated air at the
drying section becomes the first airflow amount. On the
other hand, if the grains are exposed to the air having
more than 70% humidity, the grains are not dried so that,
in order to make the heated air at the drying section the
second airflow amount, the exhaust air amount is changed
by the air exhaust means 30. In the above, the exhaust air
amount of the air exhaust means 30 has been restricted to
30% or 50% for the airflow to be predetermined amount, but
the exhaust air amount may be set appropriately so that
the heated air at the drying section may become the first
airflow or the second airflow with the boundary line being
70% of the outside air humidity. The decrease in the airflow
amount of the treated air at the drying section is due
to the decrease in the suction power of the air exhaust
means 30 whose air exhaust amount is lowered by the restriction
at the exhaust airflow control section 34.
When the stop signal for stopping the grain filling
operation is inputted to the arithmetic and control section
42 from the input section 43, the arithmetic and control
section 42 automatically stops the operation of the
drying machine 5 (Step Sll) and finishes the filling operation
program (Step S12). When the stop signal is not
inputted, the procedure returns to the Step S4 (Steps S10
through S12).
As to the temperature of the heated air produced at
the heating burner section 20 for the grain filling operation
set in advance in the ROM 43, the temperature is not
limited to the above mentioned 130°C and it may be appropriately
set. Further, it is possible to arrange that the
grain temperature sensor for detecting the temperature of
the grains be provided between the heating section and the
drying section so that the heating burner section 20 may
stop when the grain temperature reaches the predetermined
temperature and, when the grain temperature is low, the
heating burner section 20 is powered on.
According to the above steps, the heated air maintained
at 130°C from the heating burner section. 20 passes
through within each heating pipe 18 by the suction action
of the air exhaust means 30 and, after heating each heating
pipe 18 up to a predetermined temperature and after
being mixed with the outside air from the outside air intake
opening 29 in the leading-in path 28 thus the temperature
being lowered, is led into the leading-in path
27. The heated air is also mixed with the outside air
sucked into the leading-in path 27 through the outside air
intake opening 32c of the drying burner section 32 in a
stopped state so that the temperature is further lowered.
Further, after being sucked into the air exhaust means 30
through each heated air path 22, each grain flow-down
layer 24, each, air exhaust path 23, and the leading-in
path 31, the heated air is exhausted through the air exhaust
pipe 33 while being restricted by the exhaust airflow
control section 34.
Thus, when the grains introduced into the main body
17 of the drying machine flow down between the respective
heating pipes 18, the grains are heated by heat conduction
resulting from being in touch with each heating pipe 18
and by radiant heat from each heating pipe 18 and, while
flowing down through each grain flow-down layer 24, the
grains are heated but without being dried by the heated
air which passes through each grain flow-down layer 24
since such air is of a low temperature and of the airflow
adapted to the outside air humidity. In this way, the
grains are given preliminary heating during the grain
filling operation in advance to the drying operation.
Now, hereinafter the drying operation control of the
circulating type grain drying machine -5 is explained with
reference to the flow charts of Figs. 6(a) and 6(b), Symbols
A, B in circles in Fig. 6 (a) are respectively connected
to symbols A, B in circles in Fig. 6(b). First, the
operator sets and enters from the input section 43 the
amount of grains (hereinafter referred to as a "filling
amount") to be introduced into and accumulated in the main
body 17 of the drying machine, the targeted finishing water
content value, etc. This input signal is inputted
through the input/output circuit 40 into the arithmetic
and control section 42 which stores this input signal in
the RAM 46 (Step S1).
Next, when the operator presses the button for the
drying operation at the input section 43, the relevant
signal is sent to the arithmetic and control section 42
through the input/output circuit 40. The arithmetic and
control section 42 reads out the drying operation program
stored in advance in the ROM 43 and starts the execution
of the program. The arithmetic and control section 42
starts the respective operations of the scattering plate
Ha, elevator 16, screw conveyor 15, forwarding valve 14,
air exhaust means 30, heating burner section 20, and, humidity
meter 37. The heating burner section 32 is caused
to be operated several minutes later. The exhaust airflow
control section 34 is in a full-admission, and the selector
valve 16b changes its flow to the main body 17 side
(Step S2).
Next, the arithmetic and control section 42 enters an
initial value at the heated air setting temperature TA for
the heating burner section 20, and also enters an initial
value at the heated aix setting temperature TB for the
drying burner section 32 (Step S3).
Next, the humidity meter 37 detects a water content
value (water content rate) of the grains supplied to the
elevator 16 from the screw conveyor 15 and conveyed upwardly,
and the detected values are taken into the arithmetic
and control section 42 through the A/D converter 41
and the input/output circuit 40 and, thereafter, are
stored in the RAM 46 (Step S4).
Then, based on the vater content values of the grains
detected in the Step S4, the arithmetic and control section
42 determines the heated air setting temperature TA
of the heating burner section 20 at the temperatures as
shown in the Table 1. For example, if the water content
values of the grains are within the range of 21-25%, the
heated air setting temperature TA is set to 130°C and, if
the Jirater content values of the grains are within the
range of 19-21%, the heated air setting temperature TA is
set to 120°C (Step S5).
Then, based on the water content values in Step S4
and the filling amount stored in the RAM 46 in the Step
S1, the arithmetic and control section 42 determines the
setting temperature TB of the heated air supplied to each
heated air path at the temperatures as shown in the Table
1. For example, if the water content values of the grains
are within the range of 21-25% and the filling amount is
at the level "6", the heated air setting temperature TB is
set to 39°C and, if the water content values of the grains
are within the range of 19-21% and moreover the filling
amount is at the level "6", the heated air setting temperature
TB is set to 38°C (Step S6).
Then, the heated air temperature of the heating
burner section 20 is detected by the heating pipe temperature
sensor 21, and the detected temperature data are entered
into the arithmetic and control section 42 through
the A/D converter 41 and the input/output circuit 40.
Next, the arithmetic and control section 42 determines
whether the heated air temperature of: the heating
burner section 20 is "in accord" with the heating air setting
temperature TA set in advance. If the result is "out
of accord", the Step S8-1 is executed and, if the result
is "in accord", the Step S9 is executed (Step S8).
At the Step S8-1, the determination is made as to
whether the heated air from the heating burner section 20
is higher than the heated air setting temperature TA- If
the heated air temperature is higher than the heated air
setting temperature TA, the Step S8-1-1 is executed and,
if the heated air temperature is lower than TA, the Step
S8-2 is executed.
At the Step S8-1-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a
for decreasing the combustion amount of the heating burner
20b by one level (one step) and, upon receiving this signal,
the fuel adjusting circuit 20a causes the heating
burner 20b to decrease the combustion amount of the heating
burner 20b by one level.
At the Step S8-5, the arithmetic and control section
42 calculates the temperature difference between the detected
heated air temperature and the heated air setting
temperature TA and determines whether such temperature
difference is larger than 10°C. If the difference is larger
than 10°C, the Step S8-2-1 is executed. Conversely, if
the difference is smaller than 10°C, the Step S8-3 is executed.
At the Step S8-2-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a
for increasing the combustion amount of the heating burner
20b by three levels (three steps) and, on receiving this
signal, the fuel adjusting circuit 20a causes the heating
burner 20b to increase the combustion amount of the heating
burner 20b by three levels.
At the Step S8-3, the arithmetic and control section
42 determines whether the temperature difference is larger
than 5°C. If the difference is larger than 5°C, the Step
S8-3-1 is executed. Conversely, if the difference is
smaller than 5°C, the Step S8-4 is executed.
At the Step S8-3-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a
for increasing the combustion amount of the heating burner
20b by two levels (two steps) and, upon receiving this
signal, the fuel adjusting circuit 20a causes the heating-
burner 20b to increase the combustion amount of the heating
burner 20b by two levels.
At the Step S8-4, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 20a for
increasing the combustion amount of the heating burner 20b
by one level (one step) and, upon receiving this signal,
the fuel adjusting circuit 20a causes the heating burner
20b to increase the combustion amount of the heating
burner 20b by one level.
After the above Step S8-1-1, Step S8-2-1, Step S8-3-1
and Step S8-4 have been executed, the Step S9 (measurement
of the heated air temperature of the heated air path) is
executed.
At the Step S9, the heated air temperature of the
drying burner section 32 is detected by the drying section
temperature sensor 26, and the detected temperature data
are inputted into the arithmetic and control section 42
through the A/D converter 41 and the input/output circuit
40.
Next, the arithmetic and control section 42 determines
whether the water content values of the grains detected
by the Step S4 is smaller than 20%. If it is not
smaller than 20%, the Step Sll is executed and, if it is
smaller than 20%, the Step S10-1 is executed (Step S10).
At the Step S10-1, the arithmetic and control section
42 calculates, based on the water content value stored in
the RAM 46, the difference in the water content value as
of the time after the lapse of a predetermined time, and
derives a value (drying speed value) by dividing the cal-
culated difference in the water content value by such predetermined
time, and further multiplying by 60. Next, at
the Step S10-2, it is determined whether such drying speed
value corresponds to any of the classes of the drying
speed values set and stored in advance in the ROM 43. The
arithmetic and control section 42 changes the setting of
the heated air setting temperature TB of the heated air
path 22 based on the heated air temperature compensation
values of the heated air path 22 set correspondingly to
the respective classes and stored in advance in the ROM
43.
Next, at the Step Sll, the arithmetic and control
section 42 determines whether the heated air temperature
of the heated air path 22 is "in accord" with the heating
air setting temperature TB set in advance. If the result
is "out of accord", the Step Sll-1 is executed and, if the
result is "in accord", the Step S12 is executed.
At the Step Sll-1, the determination is made as to
whether the heated air xrf the heated air path 22 is larger
than the heated air setting temperature TB. If the heated
air temperature is larger than the heated air setting temperature
TB, the Step S11-1-1 is executed and, if the
heated air temperature is smaller than TB, the Step Sll-2
is executed.
At the Step Sll-1-1, the arithmetic and control sec-
tion 42 sends a signal to the fuel adjusting circuit 32a
for decreasing the combustion amount of the drying burner
32b by one level (one step) and/ upon receiving this signal,
the fuel adjusting circuit 32a causes the drying
burner 32b to decrease the combustion amount of the drying
burner 32b by one level.
At the Step Sll-2, the arithmetic and control section
42 calculates the temperature difference between the detected
heated air temperature and the heated air setting
temperature TB and determines whether such temperature
difference is larger than 10°C. If the difference is larger
than 10°C, the Step Sll-2-1 is executed. Conversely,
if the difference is smaller than 10°C, the Step Sll-3 is
executed.
At the Step Sll-2-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 32a
for increasing the combustion amount of the drying burner
32b by three levels (three steps) and, on receiving this
signal, the fuel adjusting circuit 32a causes the drying
burner 32b to increase the combustion amount of the drying
burner 32b by three Levels.
At the Step Sll-3, the arithmetic and control section
42 determines whether the temperature difference is larger
than 5°C. If the difference is larger than 5°C, the Step
S11-3-1 is executed. Conversely, if the difference is
smaller than 5°C, the Step Sll-4 is executed.
At the Step Sll-3-1, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 32a
fox increasing the combustion amount of the drying burner
32b by two levels (two steps) and, upon receiving this
signal, the fuel adjusting circuit 32a causes the drying
burner 32b to increase the combustion amount of the drying
burner 32b by two levels.
At the Step Sll-4, the arithmetic and control section
42 sends a signal to the fuel adjusting circuit 32a for
increasing the combustion amount of the drying burner 32b
by pne level (one step) and, upon receiving this signal,
the fuel adjusting circuit 32a causes the drying burner
32b to increase the combustion amount of the drying burner
32b by one level.
After the above Step Sll-1-1, Step Sll-2-1, Step Sll-
3-1 and Step S11—4 have been executed, the Step S12 is
executed.
Next, at the Step S12, the arithmetic and control
section 42 determines whether the water content value
measured at the Step S4 is below the targeted finishing
water content value eatered at the Step S1. If the water
content value is below the targeted finishing water content
value, the Step S13 is executed and, if not below,
the procedure returns to the Step S4.
At the Steps S13 and S14, the arithmetic and control
section 42 ends the drying operation program after causing
the drying machine 5 to stop automatically.
By the drying operation control in the Steps S1
through S14, the heating section 12 of the circulating
type grain drying machine 5 of the present invention maintains
the temperature of the heated air supplied to each
heating pipe 18 to the temperature adapted to the water
content value of the grain, thus enabling to effect a preliminary
heating by each heating section 12 heated by the
heated air of the above temperature. On the other hand,
the drying section 13 maintains the heated air supplied to
each heated air path 22 at the temperature adapted to the
water content value of the grain and the filling amount,
and the drying can be carried out by the heated air (drying
air) of the above temperature. Thus, the time required
for the drying of the grains can be reduced from that conventionally
required.
In order to solve the first technical problem, according
to the circulating type grain drying machine, the
control means causes the first heated air generating means
to operate and the second heated air generating means to
stop. The control means sends a signal to the exhaust airflow
control section according to the outside air humidity
detected by the outside air humidity detection means and,
by the operation of the exhaust airflow control section,
the exhaust airflow from the air exhaust means is caused
to be changed and the airflow in the drying section is
changed. Thus, each heating pipe is heated by the heated
air of the first heated air generating means, and the
heated air turns to low temperature resulting from the
mixing with the outside air introduced through the second
heated air generating means which is in a stopped state,
and the low temperature heated air is introduced into the
drying section. Since the amount of the exhaust air from
the air exhaust means is changed by the exhaust airflow
control section operated according to the outside air humidity,
the airflow of the low temperature heated air introduced
into the drying section is changed according to
the outside humidity. Thus, while flowing down between the
heating pipes, the grains introduced into the drying machine
are heated by the heart conduction caused by being in
contact with each heating pipe and by radiating heat of
each heating pipe and, while flowing down through each
grain flow-down layer, the grains are exposed to the heated
air which is of a low temperature, which passes through
each grain flow-down layer and the airflow of which is
adapted to the outside humidity, the grains are heated
without being dried. Thus, it is possible to effect the
preliminary heating of the grains during the grain filling
preliminary heated by each heating pipe heated by the temperature
which is varied as the drying progresses and
which is adapted to the water content of the grains. The
preliminarily heated grains flow down into the drying section
and, at the drying section, the heated air of the
temperature adapted to the grain water content value and
to the filling amount, thereby enabling the efficient drying
operation and also enabling the reduction in the drying
time as compared with that in the conventional machine.
While the invention has been described in its preferred
embodiments, it is to be understood that the words
which have been used are words of description rather than
limitation and that changes within the purview of the appended
claims may be made without departing from the true
scope of the invention as defined by the claims.
WE CLAIM
1. A circulating type grain drying machine comprising:
a heating section for heating grains equipped with a
plurality of heating pipes through which heated air from a
first heated air generating means passes;
a drying section arranged under said heating section,
for drying grains by supplying heated air having passed
through each heating pipe together with heated air from a
second heated air generating means;
an air exhaust means for sucking the heated air of
said drying section and exhausting said heated air to outside
the drying machine;
an exhaust airflow control section for controlling
the amount of exhaust air of said air exhaust means;
an outside air humidity detection means for detecting
an outside air humidity; and
a control means electrically connected to each of
said first heated air generating means, said second heated
air generating means, said exhaust airflow control section,
and said outside air humidity detection means,
said coatrol means causing, during the grain filling
operation, said first heated air generating means to operate
and at the same time said second heated air generating
means to stop to operate, and said exhaust airflow control
section to operate according to the detected outside air
humidity value detected by said outside air humidity de
tection means and to change the exhaust airflow of said
air exhaust means.
2. A circulating type grain drying machine as claimed in
claim 1, in which the airflow of said drying section during
the drying operation when the exhaust airflow is not
restricted by said exhaust airflow control section is used
as reference and, if the outside air humidity value is
above a predetermined humidity, the airflow of the air in
said drying section is caused to be a first airflow which
is smaller than said reference and, if the outside air
humidity value is below the predetermined value, the airflow
of the air in said drying section is caused to be a
second airflow which is even smaller than said
first airflow and, by the operation of said exhaust airflow
control section, the exhaust airflow of said air exhaust
means is caused to be changed.
3. A circulating type grain drying machine as claimed in
claim 2, in which said predetermined humidity is 70%.
4. A circulating type grain drying machine comprising:
a heating section for heating grains equipped with a
plurality of heating pipes through which heated air from a
first heated air generating means passes;
a drying section arranged under said heating section,
for drying grains by supplying heated air having passed
through each heating pipe together with heated air from a
second heated air generating means;
an air exhaust means for sucking the heated air of
said drying section and exhausting the heated air to outside
the drying machine;
a drying heated air temperature detecting means for
detecting a temperature of the heated air supplied to said
drying section;
a heating pipe heated air temperature detecting means
for detecting a temperature of the heated air supplied to
said heating pipes;
a water content detecting means for detecting water
content values of grains;
an inpat section for inputting the amount of filled
grains; and
a control means electrically connected to each of
said first heated air generating means, said second heated
air generating, means, said drying heated air temperature
detecting means, said heating pipe heated air temperature
detecting means, said water content detecting means and
said input section,
said control means controlling, during the drying
operation, said first heated air generating means to
change the temperature of the heated air supplied into
each heating pipe according to the detected value of water
content of the grains, and said second heated air generating
means to change the temperature of the heated air supplied
into said drying section according to the detected
value of water content of the grains and the value of
filled grains.
The circulating type grain drying machine is provided in which, at the grain filling
operation, a controller (39) causes a first heated air generator (20) to operate and a
second heated air generator (32) to stop operating, and also causes, according to the
detected values of the outside air humidity from an outside air humidity detector (38), an
airflow control section (34) to operate so as to change the quantity of the airflow by an
air exhaust section. Also, at the drying operation, the controller controls the first heated
air generator (20) and controls the temperature of the heated air supplied Into each
heating pipe (18) according to the detected values of the grain water content value, and
controls the temperature of the temperature of the heated air supplied Into the drying
section (32) according to the detected values of the grain water content values and the
grain filling amount.

Documents:

468-cal-2000-granted-abstract.pdf

468-cal-2000-granted-claims.pdf

468-cal-2000-granted-correspondence.pdf

468-cal-2000-granted-description (complete).pdf

468-cal-2000-granted-drawings.pdf

468-cal-2000-granted-form 1.pdf

468-cal-2000-granted-form 2.pdf

468-cal-2000-granted-form 3.pdf

468-cal-2000-granted-form 5.pdf

468-cal-2000-granted-letter patent.pdf

468-cal-2000-granted-pa.pdf

468-cal-2000-granted-reply to examination report.pdf

468-cal-2000-granted-specification.pdf

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Patent Number

212138

Indian Patent Application Number

468/CAL/2000

PG Journal Number

47/2007

Publication Date

23-Nov-2007

Grant Date

20-Nov-2007

Date of Filing

17-Aug-2000

Name of Patentee

SATAKE CORPORATION

Applicant Address

A CORPORATION ORGANISED UNDER THE LAWS OF JAPAN, 7-2, SOTOKANDA 4-CHOME, CHIYODA-KU, TOKYO 101-0021, JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	SATAKE SATORU	31-14, SANNO 3-CHOME, OOTA-KU, TOKYO 143-0023, JAPAN.
2	MATSUSHIMA HIDEAKI	C/O. SATAKE CORPORATION 7-2, SOTOKANDA 4-CHOME, CHIYODA-KU, TOKYO 101-0021, JAPAN.
3	MATSUMOTO TOSHINORI	-DO-
4	MIZUMO HIDENORI	-DO-

PCT International Classification Number

A23L 3/16.

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	237643/1999	1999-08-24	Japan