Title of Invention

METHOD FOR DISPLAYING SET INPUTS BASED ON CONDUCTIVITY METER OF BATCH WISE VACUUM PAN AND AUTOMATIC OPERATING METHOD THERE OF

Abstract

Insulating coating is applied to entire surfaces of a pair of opposing electrodes, a high frequency current is applied between the electrodes, a conductivity meter for measuring a conductivity in the slurry around the electrodes is provided within a vacuum pan, an operator first conducts manual driving of a sugar-solution decoction apparatus while monitoring the conductivity in the slurry with use of the conductivity meter to cause an output of the conductivity meter and operations of the operating valves at each control time point to be stored for opening/closing operations of the values on the basis of the stored values.

Full Text

- 1A- BACKGROUND OF THE INVENTION The present invention relates to crystallizer in chemical field or vacuum pan in the sugar industry, for example when it is desired to automatically control an electric conductivity in a slurry contained in a Batch-wise crystallizer of a Batch-wise crystal growth process with use of a conductance meter according to a set program to grow crystals in a crystal vessel or pan, a method for displaying set inputs of valve operations on a display screen with use of input set buttons in the Batch-wise crystallizer, and also to a method for automatically operating the apparatus. In a prior art batch-wise crystallizer of a type referred to above, when it is desired to grow, e.g., sugar crystals in the vacuum pan, an operator suitably operates solution and water supply valves while monitoring an electric conductivity of a slurry (thickened mixed solution containing crystals) contained in a vacuum pan to turn ON or OFF the value to thereby supply a solution containing a sugar content that acts to grow crystals and hot water that acts to dissolve unnecessary fine crystals derived therefrom. In these years, a high frequency conductivity meter has been used to control typical crystallization characteristics, due to the fact that, as a crystal - 2 - grows, a sugar solution contained in a mother liquor is absorbed and shifted to the crystal, so that a crystal (insulator) content becomes high and a reduction in a solution content results in a drop in the conductivity of the slurry. However, when the operator manually operates the valves to turn ON and OFF the valves as in the prior art, there has been a problem that different operators tend to cause variations in their operations, thus adversely affecting the quality of products and imposing a great burden on the operators. In addition, such manual operation has been used for the batch-wise vacuum pan apparatus. In a conventional capacitance type conductivity meter, as shown in Fig. 14 as an example, the content of a specific component in a substance to be measured has been found by measuring a dielectric constant of the substance present around a body-side electrode 38 longitudinally extended through an insulating block 35 and a tip end electrode 38' and also measuring a capacitance (electrostatic capacity) determined by a quantity thereof. In general, a capacitance in a mixed fluid is very small. In conductivity meters (such as CUITOMETER) based on commercial power source frequency long used so far in a sugar manufacturing industry, since a portion of a capacitance component occupied in a measured signal is about 5 orders of magnitude as small as a conductance - 3 - component therein, it has been difficult to use the conductivity meter in a control system of the vacuum pan. For this reason, a frequency as high as about 30MHz has recently been used to make the capacitance-component signal level equal to the resistivity-component signal level. In the case where frequency is changed with the same capacitance and Z=1/(C, when f1=50Hz and c=l x 10-6F, (1=2(f1=2 x 3.14 x 50= 314, Z1=1/(314 x 1 x 10-6)=10,000/3.14 = 3200 when f2=30 x 106F, (2=2(f2=2 x 3.14 x 30 x 106= 1.88 x 108, Z2=1/(1.88 x 108 x 1 x 10-6)=1/188=0.0053 A ratio of the above both is about 6 x 105. For the purpose of solving the above problems, it has been considered to automate the above crystal growing steps with use of a computer and a high-sensitivity conductivity meter for confirming a conductivity in a mother liquor. In this case, in order to operate the computer, it is necessary for an operator to enter and set relationships between a conductance in a slurry contained in a vacuum pan and ON/OFF operations of valves in the form of data. Conventionally, the slurry conductivity has been set and displayed in the form of a digital value and a solution or hot water has been supplied according to the set program. However, most set programs contain 80 steps or more when compared to the fact that the digital representation of the slurry - 4 - conductivity is done only for a single point as the next control point. For this reason, it has been hard to grasp the entire steps and thus impossible to readily consider scheduled operations. In other words, in the crystal growing program, it is important to control the rate of change of the slurry conductivity. Thus, in such a method that only a set point is digitally displayed for every point, the crystal growing program has had to be prepared while estimating the balance. For this reason, the preparation of the program requires a high-level technique and thus most operators of vacuum pan cannot easily use the program in general. There is also a method of controlling a measurement (when a stirring machine is used as a viscosity meter) of rheometric value of the slurry with use of the conventional rotary rheometric value meter for detecting a reaction and also controlling an intermittent sugar-solution decoction under control of a computer, to thereby overcome variations in the product quality caused by the manual operations of operators. However, in the rheometric value measurement, it is difficult to accurately monitor detection of the rotary reaction in a low slurry concentration range. Further, since the reaction of the stirring machine being driven under a vacuum condition is measured, a gland type stirring machine is preferable for sealing a large-diametered stirring axis, but the sealed part has a friction and thus it is hard to accurately measure its effect (rheometric value). - 5 - Furthermore, before and after replacement of the gland packing, the measured rheometric values are different because the replacement causes the torque of the rotary shaft to be changed. When measurement is done for conductivity, however, it becomes unnecessary to measure the rheometric value based on the stirring machine and also unnecessary to use the expensive stirring machine as the sensor. SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has been made, and an object thereof is to provide a method for displaying set inputs in a batch-wise vacuum pan, which can analogically display required valves for each valve operation step on a display screen and an electrical conductivity in a slurry, and which also can allow an operator to set inputs while looking at the inputs on the display screen and while accurately confirming variations in the conductivity of the slurry. Another object of the present invention is to provide a method for automatically driving a batch-wise vacuum pan, by which even an operator not having a computer knowledge, in particular, sophisticated program preparation techniques can automatically and easily prepare a program, and can smoothly drive the apparatus automatically on the basis of the above set inputs while confirming the slurry conductivity with use of a high-sensitivity conductivity meter. - 6 - In the prior art capacitance type conductivity meter mentioned above, further, when it is used at a high frequency, the value of the conductance (1/D.C. resistance) becomes nearly equal to the value of the capacitive reactance, so that it is practically possible to detect a variation in the capacitance, but the influence of a stray capacitance is also increased in proportion to the used frequency of an amplifier. In addition, since the stray capacitance is largely affected by the ambient temperature and humidity, its stability becomes serious, also making it difficult to employ a higher frequency. It is also an object of the present invention to provide a high-sensitivity conductivity meter which can be suitably used in driving the above batch-wise vacuum pan. In accordance with the present invention, the above objects are attained by previously setting a coordinate axis indicative of a conductivity in a slurry and a coordinate axis indicative of valve operation step to be perpendicular to each other on a display screen on the basis of an experiment of actually using a sugar-solution decoction apparatus and a high-sensitivity conductivity meter, selecting required valves for each valve operation step on a keyboard, moving required valve operation marks parallel to the slurry conductance coordinate axis with use of mark movement buttons, and then fixedly displaying the valve operation mark with use of a set button to set opening/closing conditions of the - 7 - valves. In a method for displaying set inputs in a batch-wise vacuum pan of the present invention, required valve is selected for each valve operation step and a conductivity for performing the opening/closing operations of the valves is displayed on the display screen- Thereby a user can set inputs while confirming an entire variation in the conductivity on the basis of the experiment of actually using the sugar-solution decoction apparatus and the high-sensitivity conductivity meter. In a method for driving a batch-wise vacuum pan apparatus in accordance with the present invention, the apparatus comprises a high-sensitivity conductivity meter for detecting a conductivity in an object contained within a vacuum pan, valve mechanisms for operating amounts of solution and hot water to be supplied into said vacuum pan, and open/close signal output means for outputting open/close signals based on opening/closing operations of the valve mechanisms; manual driving of the apparatus is previously carried out so that, when said open/close signal output means output the open/close signals at the time of the opening/closing operations of the valve mechanisms, an output of the conductivity meter, required valve mechanisms, and required opening/closing operations are sequentially stored in a controller at this time point; and then the apparatus is shifted to an automatic drive mode in which, when an - 8 - output value of the conductivity meter previously stored in the controller coincides with a detected value of the conductivity meter, the associated opening/closing operations of the valve mechanisms previously stored in the controller are carried out. In the method for automatically driving the batch-wise vacuum pan apparatus in accordance with the present invention, the manual driving of the apparatus is first carried out so that, when said open/close signal output means output the open/close signals at the time of the opening/closing operations of the valve mechanisms, the output of the conductivity meter, required valve mechanisms, and one of the opening/closing operations are inputted and stored to and in the controller to set inputs of a program for all steps; and then the apparatus is shifted to the automatic drive mode in which, when the output value of the conductivity meter previously stored in the controller coincides with the detected value of the conductivity meter, the associated valve mechanisms are opened and closed on the basis of the associated open/close data of the valve mechanisms previously stored in the controller. Whereby, the automatic driving of the apparatus can be realized based on the same valve operations as those of the manual driving thereof. Further, with respect to the conductivity meter employed in the embodiment of the present invention, insulating material is coated on the entire surfaces of electrodes of the conductivity meter as one means. - 9 - whereby a current induced by a resistive reactance component can be made practically zero so that such a problem that a measured capacitance value is influenced by the resistive reactance can be removed. Accordingly, with such an arrangement, the stability of the apparatus can be improved. Further, with respect to an operating frequency, it has been confirmed that it is only required to take only the operating levels of the detector and amplifier into consideration, and that the electrode structure based on the experimental test of the present invention can use a frequency as low by one order of magnitude as the prior art electrode structure. As a result, when its dimensional configuration is devised, the influence of the electrode by temperature and humidity can be reduced to about 1/10, whereby its stability can be correspondingly improved and inexpensive and stable elements can be used in the amplifier. Another means for reducing the operating frequency is to add a good device to the shape and dimensions of the electrodes to increase their capacitance. To this end, it is necessary to increase an facing area between the electrodes forming the capacitance and also to make small a distance between the electrodes. Since a rate (an increase in conductance to A.C. current) of increase of the capacitance is nearly the same as a rate (an increase in the conductance to a D.C. current) of reduction of a D.C. current, a sensitivity to a cane - 10 - sugar component in a non-measurement solution and a sensitivity to impurities therein are simultaneously increased. For this reason, a signal-to-noise (S/N) ratio will not be improved. That is, in a non-insulation type conductivity meter, it becomes meaningless to increase the area of the electrodes in order to increase the cane sugar component sensitivity. With respect to the electrodes of the prior art non-insulation type conductivity meter, balance must be made between their capacitance and conductance. For this reason, even when planar plates having a large surface area are disposed opposed to each other, an increase in the capacitance cancels an reduction in the resistance without any practical merit. However, when the aforementioned coating of the insulating material is employed together, only the capacitance can be increased about 10 times. As a result, in the case of the same operating frequency, the magnitude of the detected signal of the conductivity meter proportional to the capacitive inductance can be increased to about 10 times. Further, in the case of the same magnitude of signal, the operating frequency can be decreased to about 1/10. Thus, the stability can be largely increased as with the aforementioned insulating effect. With the above respects in mind, in accordance with the present invention, there is provided an insulation type conductivity meter in which insulating coating is applied on entire surfaces of a pair of opposing - 11 - electrodes and a high frequency current is applied to the electrode can to measure a conductivity in the slurry around the electrodes. With respect to the distance between the electrodes, the smaller the distance between the electrodes is the better the sensitivity is in the case of a solution containing no crystal. Thus the distance between the electrodes is preferably about 1-5mm. In the case of a slurry (solution containing crystals), since a clogging preventing or cleaning device is attached to the conductivity meter, the distance between the electrodes is preferably about 10-40mm (in which connection, the electrodes are dimensioned to be mounted to a nozzle having an aperture diameter of 4 inches or less). BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 shows schematically an arrangement of an exemplary sugar-solution decoction apparatus in accordance with the present invention. Fig. 2 is a block diagram of a controller in the arrangement of Fig. 1. Fig. 3 shows an arrangement of a keyboard section in the controller of Fig. 2. Fig. 4 is a flowchart for preparation of a program for driving the apparatus of Fig. 1. Fig. 5 is a flowchart when the apparatus of Fig. 1 is actually driven. Fig. 6 is a view for explaining exemplary data - 12 - appearing on a display screen when sugar-solution decocting steps of the embodiment are displayed. Fig. 7 is a characteristic diagram for explaining a relationship between opening/closing operations of valves and a variation with time in conductivity of massecuite within a vacuum pan when valve operations shown in Fig. 6 are carried out. Fig. 8 is a view for explaining another exemplary data when the sugar-solution decocting steps are displayed on the display screen. Fig. 9 is a characteristic diagram showing a relationship between the opening/closing operation of the valves and a variation with time in the conductivity of massecuite within the vacuum pan. Fig. 10 shows contents of a memory area in the controller. Fig. 11 is a detailed structure of an insulation type conductivity meter of an embodiment when employed in the sugar-solution decoction apparatus. Fig. 12 is a graph showing exemplary data of sugar solution measured with use of the insulation type conductivity meter of Fig. 11. Fig. 13 is a detailed structure of a modification of the insulation type conductivity meter. Fig. 14 is a structure of a prior art conductivity meter. - 13 -DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained with reference to Figs. 1 to 8. Fig. 1 schematically shows an arrangement of an example of a sugar-solution decoction apparatus embodying a method of the present invention. In the drawing, reference numeral 1 denotes a vacuum pan in which a conductivity meter 2 for detecting a conductivity in a slurry contained in the vacuum pan 1 is installed. Also coupled to the vacuum pan 1 is a piping 5, which includes a sugar solution valve 3 and a hot water supply valve 4, for supplying sugar solution and hot water into the interior of the vacuum pan 1. Further provided to the vacuum pan 1 is a level meter 6 for detecting a solution level massecuite marked on the can. Also provided within the vacuum pan 1 is a steam heat exchange 1' for supplying a constant thermal calorie thereto. An output of the conductivity meter 2 and an output of the level meter 6 are arranged to be input to a controller 7. The sugar solution valve 3 and hot water supply valve 4 are provided with limit switches 8 and 9 which detect ON and OFF operations of the respective valves, respectively. The limit switches 8 and 9, when detecting the ON and OFF operations, input ON/OFF signals based on ON/OFF operating switches to the controller 7. The controller 7, as shown in Fig. 2, includes an input/output control section 10, which receives a - 14 - conductivity from the conductivity meter 2, a level value from the level meter 6, and manual operation signals from the manual operating switches, and which sends command signals to the sugar solution valve 3 and hot water supply valve 4 and also to the other values for vacuum suction, steam supply; a central processing unit (CPU) 11 for performing a general control over the apparatus; a keyboard section 12 for entering and setting data; a display section 13 for displaying various sorts of information on a display screen; and an external storage device (floppy disk) 14 for previously storing a program therein. The keyboard section 12 is such a panel 15 having many pushbuttons mounted thereon as shown in Fig. 3, and ones of the pushbuttons associated with the present invention are a program preparation button 16, mark movement buttons 17 and 18, a set button 19, a hot water supply valve button 20, a hot water supply valve/sugar solution valve button 21, a sugar solution valve button 22, a program end button 23 and a drive start button 24. The display section 13 comprises a plasma display unit, on which display screen, in a program preparation mode and drive mode, ordinate is displayed to denote a conductivity (%) in a massecuite, abscissa is displayed to denote a valve operation step as shown in Fig. 6 or 8, and a set value SV and detected value PV of the conductivity of the massecuite are digitally - 15 - displayed in an upper left section of the screen. And displayed in the upper right section of the display screen are a mark O indicative of the operation of the sugar solution valve 3, a mark ? indicative of the operation of the hot water supply valve 4, and a mark 0 indicative of the operation of the hot water supply valve 4 and sugar solution valve 3. Further, a cursor (arrow) 27 is displayed under the abscissa to be directed upwards (open valve) or downwards (closed valve) for each valve operation step. The display screens of Figs. 6 and 8 show stopped operation states at a step 0 respectively. Explanation will next be made by referring to Fig. 4 as to such a sugar-solution decoction apparatus as arranged in the aforementioned manner in connection with a case where input data are set to prepare a program. When an operator first pushes the program preparation button 16 as shown by a step SP1, the CPU 11 changes the display screen of the display section 13 to a screen for program preparation (see Fig. 6), sets suffix n of the set value SV at 1 and suffix N of the valve operation step Step at 0, and flashes a cursor 25 downwards (closed valve) under the valve operation step Step (Step 0), as shown by steps SP2, SP3 and SP4. Then the operator pushes the mark movement buttons 17 and 18 as necessary to vertically move the mark SVn (SV1) along the valve operation step Step 0 (ordinate) on the display screen to thereby set a desired - 16 - value SVn (SV1) (step SP5). At this time, the set value SVn is digitally displayed in the upper left section of the display screen. When completing the setting, the operator pushes the set button 19 as shown by a step SP6 to determine the setting of the SVn (SV1) and to fix the display. When the CPU updates n and N by +1 as shown by a step SP7, the cursor 25 moves toward a position under the valve operation step Step N (Step 1) and flashes upwards as shown by a step SP8. Under this condition, the mark SVn (SV2) indicating to open the valve is displayed as shown by a step SP9, in which case the operator vertically moves this mark using the mark movement buttons 17 and 18 to set a desired value SVn (SV2). Subsequently, as shown by a step SP10, the operator suitably selects the 3 sorts of valve selection buttons 20, 21 and 22 as necessary to determine the valve or values to be used. This causes the marks of point SVn (SV2) indicating to open the valves to be displayed by ( (hot water supply valve 4), O (sugar solution valve 3) or [Other 2] (hot water supply valve 4 + sugar solution valve 3). Next, the CPU judges the depression or non-depression of the program end button 23. When the CPU determines that the button 23 was depressed as shown by a step SP11, the CPU performs its program preparation end operation as shown by a step SP12 to use the prepared program or store it in the external storage device 14. - 17 - When the CPU determines that the program end button 23 was not depressed in the step SP11, the CPU moves to a step SP13 to judge the depression or non-depression of the set button 19. The operation is circulated through the steps SP9 to SP13 until the set button 19 is depressed. A depression of the set button 19 causes the display SV2 to be fixed and then the cursor 25 to flash downwards under the valve operation step Step N (Step 1) as shown by a step SP14. Under this condition, the CPU updates n by +1 as shown by a step SP15 and vertically moves the mark of the point SVn (SV3) indicating to close the valves with use of the mark movement buttons 17 and 18 at a position above the valve operation step Step N (Step 1) to set a desired value SVn (SV3) as shown by a step SP16. Subsequently, the CPU monitors the depression of the set button 19 as shown by a step SP17. When the CPU determines the depression of the set button 19, it determines the set value SV3, fixes the display and then returns to the step SP7. In this way, after all the valve operation steps and conductivity of massecuite of the valve open/close point are set, a wave-shaped graph eventually appears on the display screen of the display section 13 as shown in Fig. 6 or 8. Accordingly, on the basis of a previous test on measurement of the slurry conductivity using the conductivity meter 2 in the actual apparatus, the operator can easily set inputs in the apparatus, can - 18 - grasp the condition of the entire sugar-solution decocting process, and also can easily modify the process. When the sugar-solution decoction apparatus is driven on such a program as prepared in the aforementioned manner, the CPU first judges the depression or non-depression of the drive start button 24 as shown by a step SP20 of Fig. 5. When determining the depression of the drive start button 24, the CPU sets n and N at 1 and 0 respectively as shown by steps SP21 and SP22 and flashes the cursor 25 downwards under the valve operation step Step N (Step 0). Under this condition, an objective solution (thickened solution) to be processed to grow crystals within the vacuum pan 1 is supplied into the pan. When the objective solution is supplied and the CPU confirms that the supplied solution reaches a level set by the level meter 7; the CPU stops the supply of the objective solution. When the value PVn (PV1) of the massecuite conductivity detected by the conductivity meter 2 is not smaller than the set value SVn (SV1) (step SP23), the CPU updates n and N by +1 and flashes the cursor 25 upwards at a position under the valve operation step Step (Step 1). Next, when the detected value PVn (PV2) of the massecuite conductivity is not smaller than the set value SVN (SV2) (step SP26), the CPU flashes the cursor 25 downwards at a position under the valve operation step - 19 - Step N (Step 1) and then updates n by +1 as shown by steps SP27 and SP28. Subsequently, the CPU performs opening operations of the sugar solution valve 3 and hot water supply valve 4 as shown by steps SP29 to SP32. For example, as shown in Fig. 7, at the valve operation step Step 1, the hot water supply valve 5 is opened at the detected value PV2 of the massecuite conductivity to supply hot water into the vacuum pan 1. And when the detected value PVn (PV3) of the massecuite conductivity is not larger than the set value SVn (SV3) as shown by a step SP33, the CPU closes the sugar solution valve 3 and hot water supply valve 4 so far in their open state and updates n and N by +1 as shown by steps SP34 and SP35. As shown by a step SP36, then, the CPU judges whether or not n reaches a predetermined value. If the n fails to reach the predetermined value, then CPU returns to the step SP25, whereas, if the n reaches the predetermined value, then the CPU waits until the detected value PVn of the massecuite conductivity is not larger than the set value SVn as shown by a step SP37. As soon as the above condition is satisfied, the CPU performs the step terminating operation at a step SP38, i.e., terminates the display and informs the operator of the end. In this manner, the operator can drive the sugar-solution decoction apparatus according to the prepared program. In this case, since the cursor 25 flashes upwards or downwards on the display screen for - 20 - each valve operation step, the operator can visually grasp the currently-driven stage and can easily handle the apparatus. Although explanation has been made in connection with the sugar crystal growth in the present embodiment, the present invention is not limited to the specific example but may be applied to growth steps of various sorts of crystals. Explanation will next be made as to another embodiment of driving the sugar-solution decoction apparatus according to the above display setting method. First of all, an experienced operator (sugar-solution decoction operator) manually drive the apparatus. That is, the operator operates the conductivity meter 2 and opens or closes the sugar solution valve 3 and hot water supply valve 4 while observing the slurry condition below the massecuite within the vacuum pan 1, for example, according to such a time chart as shown in Fig. 9. In this case, the opening/closing operations of the valves 3 and 4 cause the massecuite conductivity to vary as shown by a waveform of Fig. 9. This also causes the limit switches to inform the controller 7 of the opening/closing operations of the valves 3 and 4. Thus, the controller 7 inputs the then detected value of the conductivity meter 2 at each time point (MV1 to MV6) each time the controller receives an open or close signal from the limit switches, and then sequentially stores the detected values PV1 to PV6 (massecuite conductivities). - 21 - valves indicative of distinction between the sugar solution valve 3 and hot water supply valve 4, and open or closed valve states indicative of distinction between the open or closed state of the valves in a memory area 40 of the external storage device 14 with respect to each conductivity d, as shown in Fig. 10. After the manual driving is completed while input data are input to the controller 7 in this way, the automatic driving of the apparatus can be realized based on the above input data. That is, in the automatic drive mode, as in the above manual drive mode, the stock solution is supplied into the vacuum pan 1. Under this condition, the condition of the solution within the vacuum pan 1 is monitored by the conductivity meter 2 so that the detected value of the conductivity meter 2 is compared at the controller 7 with a massecuite conductivity dl previously stored in the memory area 40 of the controller 7. When the detected value of the conductivity meter 2 coincides with the massecuite conductivity d1 previously stored in the memory area 10, the sugar solution valve 3 is opened on the basis of the valve data stored in the memory area 40 as shown in Fig. 10. Next, the CPU sequentially compares the detected value of the conductivity meter 2 with the massecuite conductivity d2, d3 and d4 and, when finding a coincidence therebetween, the CPU operates the valves 3 and 4 on the basis of the associated data on the valves and on the valve - 22 -opening/closing operations. When the program confirmed in the actual sugar-solution decocting steps in the above manual drive mode is used in this way, an unskilled operator can operate the valves in the similar manner to the experienced operator (sugar-solution decocting operator) and thus can easily manufacture desired crystals. Though explanation has been made in connection with the sugar crystal growth in the present embodiment, the present invention is not restricted to the specific example but may be applied to growth steps of various sorts of crystals. Fig. 11, A and B show a detailed structure of the insulation type conductivity meter 2 used in the batch-wise vacuum pan of the present embodiment, in which Fig. 11, B is a view as seen from a line B-B in Fig. 11, A. The insulation type conductivity meter 2 includes a terminal box 31, a flange 34 provided to the terminal box 31, a body 39 extended from the flange 34, and an insulating bush 35 mounted to a tip end of the body 39. The terminal box 31 is grounded at a body earth terminal 33, and the flange 34 is used to mount the meter to the vacuum pan 1. Extended from the insulating bush 35 are opposing planar electrodes 37 and 37' which are made in the form of a parallel tuning fork made up of 2 sheets of metallic plates. Insulating coating 36 is applied on the entire surfaces of these opposing planar - 23 - electrodes 37 and 37'. These opposing planar electrodes 37 and 37' are connected with conductors led from terminals 32 and 32' within the terminal box 31, so that suitable high frequency currents can flow through the opposing planar electrodes 37 and 37'. In the crystal size control system, the insulation type conductivity meter 2 is used as a conductivity meter for detecting the degree of growth of sugar crystal. In this case, the opposing planar electrodes 37 and 37' were set to have a length L1 of 100mm, a width L2 of 30mm, and a spacing of 10mm therebetween, and to use an operating frequency of 10MHz. And the capacitance C was calculated to be L1 x L2/d.q for g=1. Shown in Fig. 12 are experimental data of conductivity of the sugar solution measured with use of the insulation type conductivity meter 2 having such a structure as shown in Fig. 11. In this experiment, 1,767g of sugar was first dissolved into 2 liters of water, 200cc of solution was removed therefrom, and then 200cc of water was newly added thereto. During this series of operations, the conductance was measured and such a nearly linear response result as illustrated was obtained. Fig. 13, A and B show another modification of the insulation type conductivity meter 2. The structure of this modification is different from that of the - 24 - modification of Fig. 11, A and B in that a single central electrode 37' is disposed between a pair of outer electrodes 37 and 37 on which insulating coating is applied and which are electrically commonly connected to each other. In the structure of the modification, there can be obtained a relatively short electrode length and a desired electrostatic capacity or capacitance. Now comparative examination will be made as to the characteristics of the prior art conductivity meter of Fig. 14 and conductivity meter having the structure of the present embodiment. For the existing cylindrical electrode in the prior art conductivity meter of Fig. 14, first, reference is made to a book entitled "Anti-Electromagnetic Wave Handbook", edited by the anti-electromagnetic wave handbook edition board, issued August 24, 1990, Articles "C) Approximation For Capacitance Calculation" and "1) Documents On Microstrip Line", page 9. In the right side of Fig. 6 showing a capacitance calculation example in the above book, a capacitance per unit length is considered to be 10-20pF/m in a range of 0.25-2 of a ratio a/b of electrode length to insulating material from an air dielectric constant curve of ey=l, assuming that a microstrip is made in the form of a ring. When typical dimensions of the existing electrode shown in Fig. 14 are used, a parallel length 1 as a circumference of the pipe is: - 25 - [Expression 1] l=(d=3.14 x 0.026m = 0.082m. a/b=30(90=0.3 and C=18pF/m (for (r=l) Accordingly, an existing electrode capacitance Ci is: [Expression 2] Ci= 18(pF/m) x 0.082(m)=1.5 (pF) A capacitance of such an opposing parallel planar electrode as shown in the embodiment is found as follows. [Expression 3] C=8.854 x Area (Sm2)/Distance (dm).(pF) When the opposing electrode shown in Fig. 13, A and B is made up of 3 sheet electrodes having dimensions of 150min x 30mm, S and d are as follows. [Expression 4] S=0.15 x 0.03= 0.045(m2) d=0.005(m) An electrode capacitance Cd obtained by the present embodiment is: [Expression 5] Cd=8.854 x 2(faces) x 0.0045(m2)/0.005(m) =15.9(pF) Cd/Ci=15.9/1.5=10.6 Thus a capacitive inductance is increased to about 10 times. The capacitive inductance is 1/(c=1/2(fc. In order to obtain the same impedance, fc is constant. That - 26 - is, in order to make the "frequency x capacitance" constant, the both must satisfy an inversely proportional relationship. Thus, when the capacitance is increased to 10 times, the frequency is required to be 1/10. As has been explained in the foregoing, in accordance with the present embodiment, there can be implemented a high-performance capacitive conductivity meter which can use a frequency one order of magnitude as low as that of the conductivity meter of the prior art structure. The conductivity meter can measure a sugar content in a non-conductive slurry. Since water is also non-conductive, the conductivity meter can also effectively measure a water content in a slurry having a high conductivity or in a dewatered cake, etc. As has been explained in the foregoing, in accordance with above embodiments, a coordinate axis indicative of conductivity and a coordinate axis indicative of valve operation step are set to be perpendicular to each other on a display screen, the valves are selected for each valve operation step, a valve operation mark is moved parallel to the conductivity coordinate axis with use of the mark movement buttons, and then the above valve operation mark is fixedly displayed using the set button to set the opening/closing conditions of the valve. Therefore, when the valve is selected for each valve operation step and the conductivity for the opening or closing operation of the valve is displayed on the display screen, the valve - 27 - and conductivity for each valve operation step can be displayed in an analog manner so that the user can conduct his input setting operation while looking at the display screen, can set while checking an entire variation in the conductivity, can eliminate the complicated operations at the time of preparing a coding program, and can confirm, prior to actual driving of the apparatus, that scheduled crystal growing operations were accurately programmed, with an excellent effect of highly easy handling. In a method for automatically driving a batch-wise vacuum pan apparatus in accordance with above embodiment, manual driving of the apparatus is first carried out so that, at the time of opening and closing operations of valve mechanisms to cause open/close signal output means to issue open/close signals; an output of a conductivity meter, the valve mechanisms, and the opening/closing operations are input and stored to and in a controller to set inputs of a program for all steps; and then the apparatus is shifted to an automatic drive mode, in which, when an actually detected value of the conductivity meter coincides with a detected value of the conductivity meter previously stored in the controller, on the basis of ON/OFF data of valve mechanisms previously stored in the controller at the same time point, the valve mechanisms are opened and closed, whereby the automation of the valve operations can be easily realized as in the manual operations and the need for performing - 28 - complicated program preparating works in the prior art can be eliminated with an excellent effect. In accordance with above embodiment, with use of a frequency as low by one order of magnitude as that of the prior art, a specific content in a non-conductive slurry can be efficiently measured. -29-WE CLAIM: 1. A method for displaying set inputs in a batch-wise crystallizer (1) comprising : applying insulating coating (36) onto entire surfaces of a pair of opposing electrodes (37, 37'); applying a high frequency current between the electrodes (37,37'); providing an insulation type conductivity meter (2) for measuring a conductivity in a slurry around the electrodes (37, 37'); and displaying valve operations on a display screen with use of an input set button (16, 17, 18, 19, 2(, 21, 22, 23, 24); characterized in that a coordinate axis indicative of the conductivity in the slurry is set to be perpendicular on the display screen to a coordinate axis indicative of valve operation step, for the valves selected for each valve operation step,a valve operation mark is moved parallel to the conductivity coordinate axis with use of mark movement buttons, said valve operation mark is first fixedly displayed with use of a set button (16, 17, 18, 19, 20, 21, 22, 23, 24), and then opening/closing conditions of valves are set. -30- 2. A method for automatically driving a sugar-solution decoction apparatus having crystals grown in a vacuum pan (1), the apparatus comprising an insulation type conductivity meter (2) for a conductivity in an object within the vacuum pan, said meter (2) having a pair of oppositing electrodes (37, 37') which have insulating coating (36) applied onto entire surfaces thereof and between which a high frequency current is applied, valve means (3,4) for operating quantum of solution and hot water to be supplied into said vacuum pan (1), and open/close signal means (8,9) for outputting open/close signals based on opening/closing operations of the valve means (3,4); the method comprising : conducting manual driving of the apparatus by an operator while monitoring the conductivity in the slurry with use of said conductivity meter (2) so that, when said open/close signal means (8,9) issue the open/close signals at the time of the opening/closing operations of the valve means (3,4), an output of the conductivity meter (2), one of the valve means (3,4) and one of the valve opening/closing operations are previously sequentially stored in a controller (7); and shifting the apparatus to its automatic drive mode, in which, when an actually detected value of said conductivity meter (2) coincides with an output value of the conductivity meter (2) -31- previously stored in the controller (7), the associated opening/closing operations of the valve means (3,4) previously stored in the controller (7) are carried out. 3. A sugar-solution decoction apparatus for carrying out the method as claimed in claim 1 or 2. 4. The apparatus as claimed in claim 3, wherein insulation type conductivity meter (2) comprising electrodes constituting of planar electrodes (37, 37') disposed parallel to each other being spaced by a predetermined distance therebetween in a longitudinal direction. 5. The apparatus as claimed in claim 3 or 4, wherein said electrodes (37, 37") comprises electridally-connected,outer electrodes (37) disposed as parallel to each other and as spaced by a predetermined distance therebetween in alongitudinal direction and an inner electrode (37") extended between the outer electrodes (37) in the longitudinal direction, and wherein a high frequency current is applied between said outer (37) and inner electrodes (37'). Dated this 12th day of December, 1997 Insulating coating is applied to entire surfaces of a pair of opposing electrodes, a high frequency current is applied between the electrodes, a conductivity meter for measuring a conductivity in the slurry around the electrodes is provided within a vacuum pan, an operator first conducts manual driving of a sugar-solution decoction apparatus while monitoring the conductivity in the slurry with use of the conductivity meter to cause an output of the conductivity meter and operations of the operating valves at each control time point to be stored for opening/closing operations of the values on the basis of the stored values.

Documents:

02360-cal-1997 abstract.pdf

02360-cal-1997 claims.pdf

02360-cal-1997 correspondence.pdf

02360-cal-1997 description(complete).pdf

02360-cal-1997 drawings.pdf

02360-cal-1997 form-1.pdf

02360-cal-1997 form-2.pdf

02360-cal-1997 form-3.pdf

02360-cal-1997 form-5.pdf

02360-cal-1997 p.a.pdf

02360-cal-1997 priority document.pdf

2360-CAL-1997-FORM-27.pdf

2360-cal-1997-granted-abstract.pdf

2360-cal-1997-granted-claims.pdf

2360-cal-1997-granted-correspondence.pdf

2360-cal-1997-granted-description (complete).pdf

2360-cal-1997-granted-drawings.pdf

2360-cal-1997-granted-examination report.pdf

2360-cal-1997-granted-form 1.pdf

2360-cal-1997-granted-form 2.pdf

2360-cal-1997-granted-form 3.pdf

2360-cal-1997-granted-form 5.pdf

2360-cal-1997-granted-letter patent.pdf

2360-cal-1997-granted-pa.pdf

2360-cal-1997-granted-reply to examination report.pdf

2360-cal-1997-granted-specification.pdf