Title of Invention

ABSORPTION CHILLER-HEATER

Abstract

An absorption chiller-heater is disclosed wherein an absorbing solution and a refrigerant are circulated through a high-temperature regenerator (1), a condenser (4), an evaporator (5) and an absorber (6), interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of said evaporator (6) is supplied to an air conditioning load to effect cooling or heating, said absorption chiller-heater comprising: a level detector; an absorbing solution pump; and a control unit, characterized in that when said level detector detects a predetermined lower-limit level of the absorbing solution, said absorbing solution pump is operated for a predetermined time at high speed to increase the amount of the absorbing solution to be fed into said high-temperature regenerator (1), then when said predetermined time has been reached or elapsed, it is determined whether said level detector detects said predetermined lower-limit level of the absorbing solution, and if the level detector detects again the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of the absorption chiller-heater are/is performed so as to warn that the predetermined lower-limit level re-detected depends on a continuous drop in normal state not temporary drop.

Full Text

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an absorption type cold/hot water machine, in other words, an absorption chiller-heater. Particularly, the present invention is concerned with a technique wherein the operation of an absorbing solution pump for feeding a dilute absorbing solution from an absorber to a high-temperature regenerator is controlled in accordance with the level of the absorbing solution present in the high-temperature regenerator. Description of the Related Art As a conventional method for coping with an abrupt change of load, particularly for remedying a lowering in the coefficient of performance of a cooling load there is known a method wherein an absorbing solution pump for feeding as a dilute absorbing solution from an absorber into a high- temperature regenerator is inverter-controlled in accordance with an absorbing solution level detector signal indicative of the level of the absorbing solution in the high-temperature regenerator, thereby matching the flow rate of the absorbing solution with the cooling load to avoid frequent ON-OFF of the absorbing solution pump caused by an abrupt change of the liquid level in the high-temperature regenerator and stabilize the operation of an absorption refrigerating machine (see, for example, Patent Document: Japanese Patent Laid-Open Publication No. Hei 3(1991)- 28674). An absorption type cold/hot water machine sometimes has a case where an absorbing solution level detector detects a lower-limit value or less of the absorbing solution level due to such an unusual state as a temporary marked change of the absorbing solution level in a high-temperature regenerator caused for example by a boiling state of the high-temperature regenerator resulting from for example an abrupt change of a cooling load at the time of start-up or during operation of the machine. Even in case of having detected such a temporary drop of the absorbing solution level, an absorbing solution pump is inverter-controlled as described above without issuing an immediate warning of a state of boil-dry or stopping the operation of the machine, and when the cooling load decreases, the level of the absorbing solution rises rapidly, but the absorbing solution pump is operated at a low frequency to avoid a marked rise of the absorbing solution level and cause the level to drop to a predetermined level. When the cooling load increases, the level of the absorbing solution drops rapidly, but the absorbing solution pump is operated at a high frequency to avoid a marked drop of the absorbing solution level and cause the level to rise up to a predetermined level. In the event there occurs an abrupt change of the absorbing solution level due to such an unusual state, a considerable time of about 5 to 10 minutes is taken until the absorbing solution level reaches the predetermined level by inverter-control of the absorbing solution pump, so there is a fear that the high-temperature regenerator may assume a state of boil-dry. Therefore, it is necessary to check as soon as possible whether the abrupt drop of the absorbing solution level is caused by the unusual state mentioned above or the absorbing solution level has dropped to the lower limit or less as a result of an increase of the cooling load in normal operation. SUMMARY OF THE INVENTION According to the present invention, in view of the above-mentioned point, it is detected quickly whether the drop of the absorbing solution level in the high-temperature regenerator to the lower limit or less is temporary or a drop in normal state, then if the drop is detected to be a temporary drop, the operation of the absorption type cold/hot water machine is continued, while if the drop is detected to be a continuous drop, there issues a warning that the machine is in a state of boil-dry, and at the same time the operation of the machine is stopped, thus making an appropriate boil-dry safety control. In a first aspect of the present invention there is provided an absorption type cold/hot water machine wherein an absorbing solution and a refrigerant are circulated through a high-temperature regenerator, a condenser, an evaporator, an absorber, and so on, interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of the evaporator is supplied to an air conditioning load to effect cooling or heating, the absorption type cold/hot water machine comprising a level detector for detecting the level of the absorbing solution in the high-temperature regenerator, an absorbing solution pump for feeding a dilute absorbing solution from the absorber into the high-temperature regenerator, and a control unit for controlling the operation of the absorbing solution pump on the basis of the detection made by the level detector, characterized in that when the level detector detects a predetermined lower-limit level of the absorbing solution, the absorbing solution pump is operated at high speed for a predetermined time to increase the amount of the absorbing solution to be fed into the high-temperature regenerator, then when the predetermined time has been reached or elapsed, it is determined whether the level detector detects the predetermined lower-limit level of the absorbing solution, and if the level detector detects the predetermined lower-limit level of the predetermined lower-limit, both or one issuance of sounding of a warning and stop of operation of the absorption type cold/hot water machine are (is) performed. In a second aspect of the present invention there is provided an absorption type cold/hot water machine wherein an absorbing solution and a refrigerant are circulated through a high-temperature regenerator, a condenser, an evaporator, an absorber, and so on, interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of the evaporator is supplied to an air conditioning load to effect cooling or heating, the absorption type cold/hot water machine comprising a level detector for detecting the level of the absorbing solution in the high-temperature regenerator, an absorbing solution pump for feeding a dilute absorbing solution from the absorber into the high-temperature refrigerator, a temperature detector for detecting the temperature of the high-temperature refrigerator, and a control unit of an inverter control type adapted to change the frequency in the range from a low frequency to a high frequency on the basis of the detection made by the temperature detector and change the number of revolutions of the absorbing solution pump, characterized in that when the level detector detects a predetermined lower-limit level of the absorbing solution, the absorbing solution pump is operated at a predetermined high frequency for a predetermined time, then when the predetermined time has been reached or elapsed, it is determined whether the level detector detects the predetermined lower-limit level of the absorbing solution, and if the level detector detects the predetermined lower-limit level, both or one issuance of sounding of a warning or stop of operation of the absorption type cold/hot water machine are (is) performed. In a third aspect of the present invention there is provided an absorption type cold/hot water machine wherein an absorbing solution and a refrigerant are circulated through a high-temperature regenerator, a condenser, an evaporator, an absorber, and so on, interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of the evaporator is supplied to an air conditioning load to effect cooling or heating, the absorption type cold/hot water machine comprising a level detector for detecting the level of the absorbing solution in the high-temperature regenerator, an absorption solution pump for feeding a dilute absorbing solution from the absorber into the high-temperature regenerator, a temperature detector for detecting the temperature of the high-temperature regenerator, and a control unit of an inverter control type adapted to change the frequency in the range from a low frequency to a high frequency on the basis of the detection made by the temperature detector and change the number of revolutions of the absorbing solution pump, characterized in that when the level detector detects a predetermined lower-limit level of the absorbing solution, the absorbing solution pump is operated at a predetermined high frequency for the predetermined time and a rise of temperature detected by the temperature detector is measured, then when the predetermined time has been reached or elapsed and when the temperature rise is a predetermined value or more and the level detector detects the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of the absorption type cold/hot water machine are (is) performed. In a fourth aspect of the present invention there is provided an absorption type cold/hot water machine comprising an absorbing solution pump for circulating an absorbing solution and a refrigerant through a high- temperature regenerator, a condenser, an evaporator, an absorber, and so on, interconnected by pipes and for feeding a dilute absorbing solution from the absorber into the high-temperature regenerator and a control unit of an inverter control type adapted to change the frequency in the range from a low frequency to a high frequency on the basis of detection of the temperature of the absorbing solution in the high-temperature regenerator and change the number of revolutions of the absorbing solution pump, a heat operation medium being supplied to an air conditioning load to effect cooling or heating, the heat operation medium being in a cooled or heated state as a result of having passed through a heat transfer pipe disposed in the interior of the evaporator, characterized in that a level detector for detecting the level of the absorbing solution in the high-temperature regenerator and a temperature detector for detecting the temperature of exhaust gas discharged from the high-temperature regenerator are provided, and when the level detector detects a predetermined lower-limit level of the absorbing solution, the absorbing solution pump is operated at a predetermined high frequency for the predetermined time and a rise of the exhaust gas temperature detected by the temperature detector is measured, then when the predetermined time has been reached or elapsed and when the temperature rise is a predetermined value or more and the level detector detects the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of the absorption type cold/hot water machine are (is) performed. According to the first aspect of the present invention described above, when the absorbing level detector detects the predetermined lower-limit level of the absorbing solution due to a temporary marked change of the absorbing solution level in the high-temperature regenerator caused for example by a boiling state of the high-temperature regenerator resulting from for example a change of a cooling load at the time of start-up or during operation of the absorption type cold/hot water machine, the liquid level can be returned to its normal level quickly by a high-speed operation of the absorbing solution pump. Thus, it is possible to make a quick and accurate determination without need of waiting for a long time for a natural recovery from the temporarily dropped liquid level. Therefore, it is possible to prevent malfunctions caused by a temporary drop of the liquid level, such as sounding of a warning and/or stop of operation of the absorption type cold/hot water machine. In the event the level of the absorbing solution drops to the lower-limit value or less in normal operation, a control is made for issuing a warning and/or stop of operation of the machine, whereby it is possible to make the boil-dry protection of the high-temperature regenerator. According to the second aspect of the present invention mentioned above there is made an inverter control such that the number of revolutions of the absorbing solution pump can be changed in the range from a low frequency to a high frequency, so when the level detector detects the predetermined lower-limit level of the absorbing solution, the absorbing solution pump is fully operated at a predetermined high frequency for a predetermined time, whereby it is possible to effect recovery up to the normal liquid level quickly. Thus, it is possible to make a quick and accurate determination without need of waiting for a long time for the natural recovery from such a temporary drop of the liquid level. Therefore, it is possible to prevent malfunctions caused by a temporary drop of the liquid level, such as sounding of a warning and stop of operation of the absorption type cold/hot water machine. At the same time, when the level of the absorbing solution drops the lower-limit level or less, a control is made to issue a warning and/or stop of the operation of the machine, whereby it is possible to make the boil-dry protection of the high- temperature regenerator. According to the third aspect of the present invention mentioned above, in addition to the second aspect, a rise in temperature of the absorbing solution in the high-temperature regenerator is measured, and when it is the predetermined value or more, it indicates an abnormal state. Therefore, when the temperature rise is equal to or above the predetermined value and the level detector detects the predetermined lower- limit level of the absorbing solution, the high-temperature regenerator is in a state of boil-dry due to a solution level drop. At this time, there issues a boil-dry warning and/or the operation of the absorption type cold/hot watrer machine is stopped, thereby informing a worker that the warning is of the state of boil-dry and hence permitting the worker to make appropriate inspection and protection. According to the fourth aspect of the present invention mentioned above, in addition to the second aspect, a rise in temperature of the high- temperature regenerator is measured, when a rise in temperature of exhaust gas discharged from the high-temperature regenerator is the predetermined value or more, it indicates an abnormal state. Therefore, when this temperature rise is equal to or above the predetermined value and the level detector detects the predetermined lower-limit level of the absorbing solution, the high-temperature regenerator is in a state of boil-dry due to a solution level drop. At this time, there issues a boil-dry warning and/or the operation of the absorption type cold/hot water machine is stopped, thereby informing a worker that the warning is of the state of boil- dry and permitting the worker to make and protection. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 is a schematic configuration diagram of an absorption type cold/hot water machine according to the present invention (the first embodiment); Fig. 2 is a control flow chart according to the first and second aspects of the present invention (the first embodiment); Fig. 3 is a diagram showing a temperature - frequency relation for inverter-controlling an absorbing solution pump according to the present invention (the first embodiment); Fig. 4 is a control flow chart according to the third and fourth aspects of the present invention (the second and the third embodiments); and Fig. 5 is a diagram showing a temperature rise detected by a temperature detector according to the third and fourth aspects of the present invention (the second and the third embodiments). DESCRIPTION OF THE PREFERRED EMBODIMENT In the absorption type cold/hot water machine according to the present invention, an absorbing solution and a refrigerant are circulated through a high-temperature regenerator, a condenser, an evaporator, an absorber, and so on, interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of the evaporator is supplied to an air conditioning load to effect cooling or heating. The absorption type cold/hot water machine includes a level detector for detecting the level of the absorbing solution in the high-temperature regenerator, an absorbing solution pump for feeding a dilute absorbing solution from the absorber into the high- temperature regenerator, and a control unit for controlling the operation of the absorbing solution pump on the basis of the detection made by the level detector. According to the absorption type cold/hot water machine, when the level detector detects a predetermined lower-limit level of the absorbing solution, the absorbing solution pump is operated at high speed for a predetermined time to increase the amount of the absorbing solution to be fed into the high-temperature regenerator, then when the predetermined time has been reached or elapsed, it is determined whether the level detector detects the predetermined lower-limit level of the absorbing solution, and if the level detector detects the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of the absorption type cold/hot water machine are (is) performed. Embodiments of the present invention will be described hereunder. An absorption type cold/hot water machine according to an embodiment of the present invention will be described below. Fig. 1 is a schematic configuration diagram of the absorption type cold/hot water machine, Fig. 2 is a control flow chart related to the first and the second aspects of the present invention, and Fig. 3 illustrates a temperature frequency relation for inverter-controlling an absorbing solution pump. An embodiment of the present invention will now be described. Fig. 1 schematically illustrates the configuration of an absorption type cold/hot water machine P using water as a refrigerant and lithium bromide (LiBr) as an absorbing solution. A high-temperature regenerator 1 is configured so as to heat a dilute solution containing both absorbing solution and refrigerant with heat of a gas burner 2 which uses, for example, city gas as fuel, allowing the refrigerant to evaporate and thereby causing the absorbing solution and the refrigerant to become separated from each other. Numeral 3 denotes a low-temperature regenerator, numeral 4 denotes a condenser, 5 an evaporator, 6 an absorber, 7 a low-temperature heat exchanger, 8 a high-temperature heat exchanger, numerals 9 to 11 denote absorbing solution pipes, numeral 12 denotes an absorbing solution pump having a mechanism such that its pump section is rotated by an electric motor, numerals 13 to 15 denote refrigerant pipes, 16 a refrigerant pump, 17 a cold/hot water pipe, 18 a cooling water pipe, 19 a gas supply pipe for the supply of gas to the gas burner 2, numeral 20 denotes a fuel valve for controlling the amount of gas to be supplied to the gas burner 2, numeral 21 denotes a temperature detector attached to an output pipe 17B of the cold/hot water pipe 17 for detecting the temperature of cold or hot water flowing out from the outlet pipe 17B, and numeral 22 denotes a burner controller for controlling the degree of opening of the fuel valve 20 in accordance with the result of temperature detection made by the temperature detector 21. Numeral 23 denotes a blower for feeding air into the gas burner 2 and numeral 24 denotes an igniter for igniting the gas in the gas burner 2. Numeral 25 denotes a second absorbing solution pump, numerals 26, 27 and 28 denote opening/closing valves, numeral 29 denotes a temperature detector for detecting the temperature of the absorbing solution in the high- temperature regenerator 1, numeral 30 denotes a level detector for detecting the level of the absorbing solution in the high-temperature regenerator 1, numeral 31 denotes a temperature detector for detecting the temperature of exhaust gas of the high-temperature regenerator, numeral 32 denotes an inverter controller for inverter-controlling the absorbing solution pump 12, and numeral 33 denotes a control unit including both burner controller 22 and inverter controller 32 to control the operation of the absorption type cold/hot water machine P. The control unit 33 further includes an MPU (microprocessor unit), a ROM for the storage of programs, a RAM for the storage of data such as temperature data, and an input/output interface serving as communication means, to control the operation of the absorption type cold/hot water machine P. The absorption type cold/hot water machine P is operated switchingly between a cooling operation of taking out cold water from the outlet pipe 17B of the cold/hot water pipe 17 and a heating operation of taking out hot water from the outlet pipe 17B. In the cooling operation, the opening/closing valves 26, 27 and 28 are closed, allowing cooling water to flow through the cooling water pipe 18, and the gas burner 2 is ignited by the igniter 24 to heat the absorbing solution in the high-temperature regenerator 1, whereby there are obtained refrigerant vapor separated by evaporation from the absorbing solution and an intermediate absorbing solution increased in condensation after separation of the refrigerant vapor. The refrigerant vapor of a high temperature produced in the high- temperature regenerator 1 passes through the refrigerant pipe 13 and enters the low-temperature regenerator 3 to heat the intermediate absorbing solution having been produced in the high-temperature regenerator 1 and entered the low-temperature regenerator 2 through the high-temperature heat exchanger 8 by the absorbing solution pipe 10, thus radiates heat, condenses and enters the condenser 4. On the other hand, the refrigerant having been heated in the low-temperature regenerator 3 and evaporated off from the intermediate absorbing solution gets into the condenser 4, heat-exchanges with water flowing through the interior of the heat transfer pipe ISA from the cooling water pipe 18, thereby condenses into liquid, then passes through the refrigerant pipe 14 together with the condensed refrigerant supplied from the refrigerant pipe 13, and enters the evaporator 5. The refrigerant liquid having entered the evaporator 5 and accumulated in a refrigerant sump formed in the bottom of the evaporator is sprinkled by the refrigerant pump 16 over a heat transfer pipe 17A connected to the cold/hot water pipe 17, then heat-exchanges with water which is supplied through the cold/hot water pipe 17, thereby evaporates and cools water flowing through the interior of the heat transfer pipe 17A. The refrigerant evaporated in the evaporator 5 enters the absorber 6 and is absorbed by the absorbing solution whose condensation has been further increased by being heated in the low-temperature regenerator 3 to evaporate off the refrigerant, i.e., the condensed absorbing solution which is supplied from the absorbing solution pipe 11 through the low-temperature heat exchanger 7 by the pump 25 and sprinkled from above. The absorbing solution whose condensation has been decreased by absorbing the refrigerant in the absorber 6, i.e., a dilute absorbing solution, is fed from the absorbing solution pipe 9 to the high-temperature regenerator 1 through the low-temperature heat exchanger 7 and the high-temperature heat exchanger 8 by the operation of the absorbing solution pump 12. With the operation of the absorption type cold/hot water machine performed in the above-mentioned manner, if cold water which has been cooled by the heat of vaporization of the refrigerant in the heat transfer pipe 17A disposed in the interior of the evaporator 5 is supplied circulatively to an indoor unit (not shown) through the outlet pipe 17B of the cold/hot water pipe 17, it is possible to perform a cooling operation. On the other hand, for a heating operation, the opening/closing valves 26, 27 and 28 are opened, then the gas burner 2 is ignited by the igniter 24 without flowing cooling water into the cooling water pipe 18, and the dilute absorbing solution is heated in the high-temperature regenerator 1. As a result, the refrigerant evaporated from the dilute absorbing solution in the high-temperature regenerator 1 passes mainly through a refrigerant pipe 13A of a low channel resistance from an intermediate position of the refrigerant pipe 13, enters the absorber 6 and the evaporator 5, then heat-exchanges through the heat transfer pipe 17A with water supplied from the cold/hot water pipe 17 and condenses thereby. Mainly with the resulting condensation heat, the water flowing through the interior of the heat transfer pipe 17A is heated. The refrigerant condensed after heating in the evaporator 5 is fed from the refrigerant sump formed in the bottom of the evaporator 5 into the absorber 6 through the opening/closing valve 28 by means of the refrigerant pump 16, then is mixed with the absorbing solution which flows into the absorber 6 through the opening/closing valve 27 after evaporation and separation of the refrigerant in the high-temperature regenerator 1, then by operation of the absorbing solution pump 12 the resulting mixture is fed from the absorbing solution pipe 9 into the high-temperature regenerator 1 through the low-temperature heat exchanger 7 and the high-temperature heat exchanger 8. Hot water heated by the heat transfer pipe 17A in the interior of the evaporator 5 is supplied circulatively to the indoor unit (not shown) through the outlet pipe 17B of the cold/hot water pipe 17, whereby a heating operation is performed. The control unit 33 controls the operation of the absorbing solution pump 12 in accordance with the result of detection made by the level detector 30. When the level detector 30 detects the lower-limit level or less of the absorbing solution, the absorbing solution pump 12 is operated at high speed for a predetermined time to increase the amount of the absorbing solution fed into the high-temperature regenerator 1. Then, upon arrival at or lapse of the predetermined time, the control unit 33 determines whether the detector 30 is detecting the lower-limit level or less of the level absorbing solution, When the detector 30 is detecting the lower-limit level or less of the level of the absorbing solution, the control unit 33 makes control so as to perform both or one issuance of sounding of a warning and stop of operation of the absorption type cold/hot water machine P. A more concrete configuration will now be described. A detection output of the temperature detector 29 which detects the temperature of the absorbing solution in the high-temperature regenerator 1 and a detection output of a temperature detector 34 which detects an inlet temperature of cooling water flowing into the cooling water pipe 18 are inputted to the control unit 33. In the cooling operation as shown in Fig.3, when on the basis of the detection outputs of the temperature detectors 29 and 34 the temperature of the absorbing solution in the high-temperature regenerator 1 is found to change for example in the range of 90° C to 160°C correspondingly to each range of the cooling water inlet temperature defined in increments of 2°C for example from 22°C to 32°C, there is made an adjustment so that the frequency changes continuously or stepwise for example in the range of 28 to 60 Hz, whereby the higher the temperature of the absorbing solution in the high-temperature regenerator 1, the higher the frequency signal which the control unit 33 outputs on the basis of the input provided from the temperature detector 29. Consequently, the frequency of electric power outputted from the inverter controller 32 to the electric motor of the absorbing solution pump 12 becomes high and the absorbing solution pump 12 assumes a state of high-speed operation, resulting in that the delivery of the absorbing solution pump 12 increases. Besides, the lower the temperature of the absorbing solution in the high-temperature regenerator 1, the lower the frequency signal which the control unit 33 outputs on the basis of the input provided from the temperature detector 29. Consequently, the frequency of electric power outputted from the inverter controller 32 to the electric motor of the absorbing solution pump 21 becomes low and the absorbing solution pump 12 assumes a state of low- speed operation, resulting in that the delivery of the absorbing solution pump 12 decreases. In the heating operation, cooling water is not allowed to flow into the cooling water pipe 18 as noted above, so that the higher the temperature of the absorbing solution in the high-temperature regenerator 1 on the basis of the detection output of the temperature detector 29 as a detector for detecting the temperature of the absorbing solution in the high-temperature regenerator 1, which is inputted to the control unit 33, the higher the frequency signal which the control unit 33 outputs on the basis of the input provided from the temperature detector 29 as mentioned above. Consequently, the frequency of electric power outputted from the inverter controller 32 to the electric motor of the absorbing solution pump 12 becomes high and the absorbing solution pump 12 assumes a state of high- speed operation, with the result that the delivery of the absorbing solution pump 12 increases. Moreover, the lower the temperature of the absorbing solution in the high-temperature regenerator 1, the lower the frequency signal which the control unit 33 outputs on the basis of the input provided from the temperature detector 29. Consequently, the frequency of electric power outputted from the inverter controller 32 to the electric motor of the absorbing solution pump 12 becomes low and the absorbing solution pump 12 assumes a state of low-speed operation, with consequent decrease of the delivery of the absorbing solution pump 12. Thus, the frequency of electric power outputted from the inverter controller 32 in the control unit 33 to the absorbing solution pump 12 varies at least in accordance with the temperature of the absorbing solution in the high-temperature regenerator 1. Thus, the absorbing solution pump 12 is inverter-controlled so that the number of revolutions thereof changes, whereby the level of the absorbing solution in the high-temperature regenerator 1 is maintained at an appropriate level. Although in the above configuration the temperature of the high- temperature regenerator is detected by the temperature detector 29 which detects the temperature of the absorbing solution in the high-temperature regenerator 1, there may be adopted a configuration using the temperature detector 31 which detects the temperature of exhaust gas discharged from the high-temperature regenerator 1. The level detector 30 has three electrodes A, B and C for detecting the level of the absorbing solution in the high-temperature regenerator 1, of which the electrode B is a common electrode. When the level of the absorbing solution rises and reaches the electrode A, the electrodes A and B become conductive and the control unit 33 operates so as to detect a high level (upper-limit level). When the level of the absorbing solution drops lower than the electrode C and the electrodes B and C become non- conductive, the state of detection becomes a low level (lower-limit level) detecting state and the control unit 33 operates accordingly. Thus, an absorbing solution level range from the electrode C to the electrode A represents a normal state of the amount of the absorbing solution. This is determined by the control unit 33 and the absorbing solution pump 12 is inverter-controlled in the manner described above. Thus, the absorbing solution level range from the electrode C to the electrode A corresponds to a normal state of the amount of the absorbing solution. In this state, as noted above and as shown in Fig. 3, the absorbing solution pump 12 is inverter-controlled in the range of 28 to 60 Hz. If in this state of operation there occurs a rise of the absorbing solution level frequently in a short time by some causes, the electric power frequency supplied to the absorbing solution pump 12 is lowered. For example, when the electric power frequency supplied to the absorbing solution pump 12 which is in operation under inverter control is 40 Hz, the number of times the level of the absorbing solution reaches the electrode A within a has dropped to the lower-limit level or less, the processing flow advances to step S3. In step S3, the absorbing solution pump 12 is operated in a state of highest speed within its operation range or at a high speed close thereto. In this embodiment the absorbing solution pump 12 is operated for a predetermined time at the maximum frequency of 60 Hz under inverter control. In this embodiment the predetermined time is 60 seconds, but may be any time in the range of 30 to 60 seconds. In step S4, if during the aforesaid period of 60 seconds the level of the absorbing solution rises and the electrodes B and C become conductive and so do the electrodes A and C, then at this instant the processing flow advances to step S6. However, if during this 60 sec. period the solution level does not rise so as to bring the electrodes A and C into conduction, the processing flow advances to step S5 in 60 seconds (upon arrival at 60 seconds or after the lapse of 60 seconds). In step S5 it is determined whether the electrodes B and C are conductive, i.e., whether the level of the absorbing solution in the high-temperature regenerator 1 is the lower-limit level or more. If the answer is affirmative, the processing flow advances to step S6. In step S6, the absorption type cold/hot water machine P is in normal operation and the frequency of electric power outputted from the inverter controller 32 in the control unit 33 to the absorbing solution pump 12 changes in accordance with the temperature of the absorbing solution in the high-temperature regenerator 1, whereby the absorbing solution pump 12 is inverter-controlled so that the number of revolutions thereof changes and the level of the absorbing solution in the high-temperature regenerator 1 is maintained at an appropriate absorbing solution level. If in step S5 the electrodes B and C are non-conductive, i.e., the lower-limit level has not been reached, it is determined that the level of the absorbing solution in the high-temperature regenerator 1 is in an abnormal deficient state, and the processing flow advances to step S7, in which a warning indicative of the abnormal state is issued. This "abnormal" warning is issued, for example, by sounding of a buzzer or lighting of a lamp. In step S7 the operation of the absorption type cold/hot water machine P may be stopped. The control unit 33 may make a control so that both or one of such issuance of the warning and stop of operation of the machine P are (is) performed. After arrival at step S6 in the operation, the processing flow advances to step S1, followed by the same determinations as above and each determination is made. In this way the operations of steps S1 to S6 are repeated. According to the present invention, when the level of the absorbing solution drops to the predetermined lower-limit level, that is, when the electrodes B and C cease to conduct and become non-conductive, this state indicates the deficiency of the absorbing solution, but it is determined by the control unit 33 whether this state is attributable to a temporary change of the absorbing solution level or not. Further, another means for this determining operation will be described with reference to Figs. 4 and 5. The configuration and operation of the absorption type cold/hot water machine P are the same as in Figs. 1 and 3. In this case, the detection output of the temperature detector 29 for detecting the temperature of the absorbing solution in the high-temperature regenerator 1 is inputted to the control unit 33. The absorbing solution pump 12 is in a state of being inverter-controlled in the range of 28 to 60 Hz, as shown in Fig. 3. Fig. 4 is a control flow chart and Fig. 5 is a diagram showing a temperature rise detected by a temperature detector, both in connection with the present invention. In Fig. 4, the level of the absorbing solution in the high-temperature regenerator 1 is detected by the level detector 30 in step S1. In step S2, it is determined whether the absorbing solution level has dropped to the lower-limit value or less, i.e., whether the electrodes B and C are non- conductive or not, and if the electrodes B and C are conductive, the processing flow advances to step S7, while if the electrodes B and C are non- conductive and the lower-limit level or less is detected, the processing flow advances to step S3. In step S3, the absorbing solution pump 12 is operated at high speed. In the embodiment, the operation is performed for a predetermined time at the maximum frequency of 60 Hz which is inverter- controlled. In the embodiment the predetermined time is 60 seconds, but may be any other time falling under the range of 30 to 60 seconds. In step S4, if during the 60 sec. period the solution level rises and the electrodes B and C become conductive and so do the electrodes A and C, the processing flow advances to step S7 on the moment. However, if during the 60 sec. period the solution level does not rise so as to bring the electrodes A and C into conduction, the processing flow advances to step S5 in 60 seconds (upon arrival at 60 seconds or after the lapse of 60 seconds). In step S5, it is determined whether the electrodes B and C are conductive or not, i.e., whether the level of the absorbing solution in the high- temperature regenerator 1 is the lower-limit level or more. If the answer is affirmative, the processing flow advances to step S6, but if the electrodes B and C are non-conductive, i.e., if the lower-limit level has not been reached, it is determined that the level of the absorbing solution in the high- temperature regenerator 1 is in an abnormal deficient state, then the processing flow advances to step S8, in which a warning indicative of the abnormal state is issued. This "abnormal" warning is issued, for example, by sounding of a buzzer or lighting of a lamp. In step S8, the operation of the absorption type cold/hot water machine P may be stopped. The control unit 33 may make a control so that both or one of such issuance of the warning and stop of operation of the machine P are (is) performed. If in step S5 the electrodes B and C are conductive, i.e., if the lower- limit level has been reached, the processing flow advances to step S6. In step S6, as shown in Fig. 5, on the basis of the detection output of the temperature detector 29 which is inputted to the control unit 33, it is determined whether the temperature rise of the absorbing solution in the high-temperature regenerator 1 is within a prescribed range or not. In the embodiment, it is determined whether the temperature rise of the absorbing solution in the high-temperature regenerator 1 is a predetermined value (5°C) or more in a predetermined time (15 seconds). The temperatures shown on the left side of Fig. 5 do not constitute any limitation. In step S6, if the temperature rise of the absorbing solution in the high-temperature regenerator 1 is within the prescribed range, i.e., if it does not reach the predetermined value (5°C) in the predetermined time (15 seconds), this means that the high-temperature regenerator 1 is within a safe range, therefore, the processing flow advances to step S6. If the temperature rise of the absorbing solution in the high-temperature regenerator 1 exceeds the predetermined range, i.e., if it is the predetermined value (5°C) or more in the predetermined time (15 seconds), this means that the high-temperature regenerator 1 is in a dangerous range, therefore, the processing flow advances to step S8, in which a warning indicative of this abnormal state is issued. This "abnormal" warning is issued, for example, by sounding of a buzzer or lighting of a lamp. In step S8, the operation of the absorption type cold/hot water machine P may be stopped. The control unit 33 may make a control so that both or one of such issuance of the warning and stop of operation of the machine P are (is) performed. In step S7, the absorption type cold/hot water machine P is in normal operation, and as noted above, the frequency of electric power outputted from the inverter controller 32 in the control unit 33 to the absorbing solution pump 12 changes in accordance with the temperature of the absorbing solution in the high-temperature regenerator 1, whereby the absorbing solution pump 12 is inverter-controlled so that the number of revolutions thereof changes. In this way the lever of the absorbing solution in the high-temperature regenerator 1 is maintained at an appropriate level. Thus, when the level detector 30 detects a drop of the absorbing solution level to the lower-limit value or less, the control unit 33 makes control so that the absorbing solution pump 12 operates at a predetermined high frequency for a predetermined time. At the same time, a temperature rise of the absorbing solution in the high-temperature regenerator 1 is measured. Then, when the temperature rise is the predetermined value or more and the level detector 30 detects the lower-limit level or less of the absorbing solution upon arrival at or lapse of the predetermined time, the issuance of a warning and/or the stop of operation of the absorption type cold/hot water machine are (is) performed. After arrival at step S7, the processing flow advances to step S1, followed by each determination in the same steps as mentioned above. In this way the operations from step SI to step S7 are repeated. According to the present invention, when the level of the absorbing solution drops to the predetermined lower-limit level, that is, when the electrodes B and C cease to conduct and become non-conductive, this state indicates the deficiency of the absorbing solution, but it is determined by the control unit 33 whether this state is attributable to a temporary change of the absorbing solution level or not. Further, still another means for this determining operation will be described with reference to Figs. 4 and 5. The configuration and operation of the absorption type cold/hot water machine P are the same as in Figs. 1 and 3. In this case, the detection output of the temperature detector 31 for detecting the temperature of exhaust gas discharged from the high-temperature regenerator 1 is inputted to the control unit 33. The absorbing solution pump 12 is in a state of being inverter-controlled in the range of 28 to 60 Hz, as shown in Fig. 3. Fig. 4 is a control flow chart and Fig. 5 is a diagram showing a temperature rise detected by a temperature detector, both in connection with the invention. In Fig. 4, the level of the absorbing solution in the high-temperature regenerator 1 is detected by the level detector 30 in step S1. In step S2, it is determined whether the absorbing solution level has dropped to the lower-limit value or less, i.e., whether the electrodes B a and C are non- conductive or not, and if the electrodes B and C are conductive, the processing flow advances to step S7, while if the electrodes B and C are non- conductive and the lower-limit level or less is detected, the processing flow advances to step S3. In step S3, the absorbing solution pump 12 is operated at high speed. In the embodiment the operation is performed for a predetermined time at the maximum frequency of 60 Hz which is inverter- controlled. In the embodiment the predetermined time is 60 seconds, but may be any other time falling under the range of 30 to 60 seconds. In step S4, if during the 60 sec. period the solution level rises and the electrodes B and C become conductive and so do the electrodes A and C, the processing flow advances to step S7 on the moment. However, if during the 60 sec. period the solution level does not rise so as to bring the electrodes A and C into conduction, the processing flow advances to step S5 in 60 seconds (upon arrival at 60 seconds or after the lapse of 60 seconds). In step S5, it is determined whether the electrodes B and C are conductive or not, i.e., whether the level of the absorbing solution in the high- temperature regenerator 1 is the lower-limit level or more. If the answer is affirmative, the processing flow advances to step S6, but if the electrodes B and C are non-conductive, i.e., if the lower-limit level has not been reached, it is determined that the level of the absorbing solution in the high- temperature regenerator 1 is in an abnormal deficient state, then the processing flow advances to step S8, in which a warning indicative of the abnormal state is issued. This "abnormal" warning is issued, for example, by sounding of a buzzer or lighting of a lamp. In step S8, the operation of the absorption type cold/hot water machine P may be stopped. The control unit 33 may make a control so that both or one of such issuance of the warning and stop of operation of the machine P are (is) performed. If in step S5 the electrodes B and C are conductive, i.e., if the lower- limit level has been reached, the processing flow advances to step S6. In step S6, as shown in Fig. 5, on the basis of the detection output of the temperature detector 31 which is inputted to the control unit 33, it is determined whether the temperature rise of exhaust gas discharged from the high-temperature regenerator 1 is within a prescribed range or not. In the embodiment, it is determined whether the temperature rise of exhaust gas from the high-temperature regenerator 1 is a predetermined value (5°C) or more in a predetermined time (15 seconds). The temperatures shown on the left side of Fig. 5 do not constitute any limitation. In step S6, if the temperature rise of the exhaust gas from the high- temperature regenerator 1 is within the prescribed range, i.e., if it does not reach the predetermined value (5°C) in the predetermined time (15 seconds), this means that the high-temperature regenerator 1 is within a safe range, therefore, the processing flow advances to step S6. If the temperature rise of the exhaust gas from the high-temperature regenerator 1 exceeds the prescribed range, i.e., if it is the predetermined value (5°C) or more in the predetermined time (15 seconds), this means that the high-temperature regenerator 1 is in a dangerous range, therefore, the processing flow advances to step S8, in which a warning indicative of this abnormal state is issued. This "abnormal" warning is issued, for example, by sounding of a buzzer or lighting of a lamp. In step S8, the operation of the absorption type cold/hot water machine P may be stopped. The control unit 33 may make a control so that both or one of such issuance of the warning and stop of operation of the machine P are (is) performed. In step S7. the absorption type cold/hot water machine P is in normal operation, and as noted above, the frequency of electric power outputted from the inverter controller 32 in the control unit 33 to the absorbing solution pump 12 changes in accordance with the temperature of the absorbing solution in the high-temperature regenerator 1, whereby the absorbing solution pump 12 is inverter-controlled so that the number of revolutions thereof changes. In this way the level of the absorbing solution in the high-temperature regenerator 1 is maintained at an appropriate level. Thus, when the level detector 30 detects a drop of the absorbing solution level to the predetermined lower-limit level, i.e., when it is detected that the electrodes B and C in the level detector 30 have come into a non- conductive state, the control unit 33 makes control so that the absorbing solution pump 12 operates at a predetermined high frequency for a predetermined time. At the same time, a temperature rise of the exhaust gas from the high-temperature regenerator 1 is measured. Then, when the temperature rise is the predetermined value or more and the level detector 30 detects the lower-limit level or less of the absorbing solution upon arrival at or lapse of the predetermined time, the issuance of a warning and/or the stop of operation of the absorption type cold/hot water machine are (is) performed. After arrival at step S7, the processing flow advances to step S1, followed by each determination in the same steps as mentioned above. In this way the operations from step S1 to step S7 are repeated. In the above second and third embodiments the order of steps S5 and S6 may be reversed so that step S6 is performed before step S5 is performed. Although in the above embodiments the upper- and lower-limit levels of the absorbing solution are detected by the level detector 30 using three electrodes A, B and C of different lengths, no limitation is made thereto. For example, there may be adopted a configuration wherein the level detector 30 is made up four electrodes D, E, F and G of different lengths, the upper-limit level of the absorbing solution is detected by conduction of the electrodes D and E, the lower-limit level thereof is detected by conduction of the electrodes F and G, an intermediate solution level is detected by the electrodes E and F, and the absorbing solution pump 12 is inverter-controlled in the same manner as mentioned above between the upper- and the lower-limit level. As to piping, control mechanism, and so on in the absorption type cold/hot water machine according to the present invention, various changes may be made and no limitation is made to the above embodiments. The present invention is applicable to various forms insofar as they do not depart from the technical scope of the invention. WE CLAIM: 1. An absorption chiller-heater wherein an absorbing solution and a refrigerant are circulated through a high-temperature regenerator, a condenser, an evaporator and an absorber, interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of said evaporator is supplied to an air conditioning load to effect cooling or heating, said absorption chiller-heater comprising: a level detector for detecting the level of the absorbing solution in said high- temperature regenerator; an absorbing solution pump for feeding a dilute absorbing solution from said absorber into said high-temperature regenerator; and a control unit for controlling the operation of said absorbing solution pump on the basis of the detection made by said level detector, characterized in that when said level detector detects a predetermined lower-limit level of the absorbing solution, said absorbing solution pump is operated for a predetermined time at high speed to increase the amount of the absorbing solution to be fed into said high- temperature regenerator, then when said predetermined time has been reached or elapsed, it is determined whether said level detector detects said predetermined lower-limit level of the absorbing solution, and if the level detector detects again the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of the absorption chiller-heater are/is performed so as to warn that the predetermined lower- limit level re-detected depends on a continuous drop in normal state not temporary drop. 2. The absorption chiller-heater as claimed in claim 1, wherein said absorption chiller-heater comprises: a temperature detector for detecting a temperature of the absorbing solution in the high-temperature regenerator; the control unit is a control unit of an inverter control type adapted to change the frequency in the range from a low frequency to a high frequency on the basis of the detection made by said temperature detector and change the number of revolutions of said absorbing solution pump, when the level detector detects the predetermined lower-limit level of the absorbing solution, the absorbing solution pump is operated for the predetermined time at the high speed by a predetermined high frequency, 3. The absorption chiller-heater as claimed in claim 2, wherein when the level detector detects the predetermined lower-limit level of the absorbing solution, a rise of the temperature detected by the temperature detector is further measured, then when the predetermined time has been reached or elapsed, and if a rise of the temperature of the absorbing solution measured is a predetermined value or more and the level detector again detects the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of said absorption chiller-heater are/is performed. 4. The absorption chiller-heater as claimed in claim 2, wherein said absorption chiller- heater comprises an exhaust gas temperature detector for detecting the temperature of exhaust gas discharged from said high-temperature regenerator, and when said level detector detects a predetermined lower-limit level of the absorbing solution, a rise of the exhaust gas temperature detected by said exhaust gas temperature detector is further measured, then when the predetermined time has been reached or elapsed, and if a rise of the exhaust gas temperature measured is a predetermined value or more and the level detector again detects the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of said absorption chiller-heater are/is performed. ABSTRACT ABSORPTION CHILLER-HEATER An absorption chiller-heater is disclosed wherein an absorbing solution and a refrigerant are circulated through a high-temperature regenerator (1), a condenser (4), an evaporator (5) and an absorber (6), interconnected by pipes and a heat operation medium cooled or heated as a result of having passed through a heat transfer pipe disposed in the interior of said evaporator (6) is supplied to an air conditioning load to effect cooling or heating, said absorption chiller-heater comprising: a level detector; an absorbing solution pump; and a control unit, characterized in that when said level detector detects a predetermined lower-limit level of the absorbing solution, said absorbing solution pump is operated for a predetermined time at high speed to increase the amount of the absorbing solution to be fed into said high-temperature regenerator (1), then when said predetermined time has been reached or elapsed, it is determined whether said level detector detects said predetermined lower-limit level of the absorbing solution, and if the level detector detects again the predetermined lower-limit level of the absorbing solution, both or one issuance of sounding of a warning and stop of operation of the absorption chiller-heater are/is performed so as to warn that the predetermined lower-limit level re-detected depends on a continuous drop in normal state not temporary drop.

Documents:

01175-kol-2007-abstract.pdf

01175-kol-2007-claims.pdf

01175-kol-2007-correspondence others.pdf

01175-kol-2007-description complete.pdf

01175-kol-2007-drawings.pdf

01175-kol-2007-form 1.pdf

01175-kol-2007-form 2.pdf

01175-kol-2007-form 3.pdf

01175-kol-2007-form 5.pdf

01175-kol-2007-others.pdf

01175-kol-2007-priority document.pdf

1175-KOL-2007-(01-06-2012)-ABSTRACT.pdf

1175-KOL-2007-(01-06-2012)-AMANDED CLAIMS.pdf

1175-KOL-2007-(01-06-2012)-AMANDED PAGES OF SPECIFICATION.pdf

1175-KOL-2007-(01-06-2012)-CORRESPONDENCE.pdf

1175-KOL-2007-(01-06-2012)-DESCRIPTION (COMPLETE).pdf

1175-KOL-2007-(01-06-2012)-FORM-1.pdf

1175-KOL-2007-(01-06-2012)-FORM-2.pdf

1175-KOL-2007-(01-06-2012)-FORM-3.pdf

1175-KOL-2007-(01-06-2012)-FORM-5.pdf

1175-KOL-2007-(01-06-2012)-OTHERS.pdf

1175-KOL-2007-(01-06-2012)-PA.pdf

1175-KOL-2007-(01-06-2012)-PETITION UNDER RULE 137.pdf

1175-KOL-2007-(13-06-2012)-AMANDED PAGES OF SPECIFICATION.pdf

1175-KOL-2007-(15-06-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf

1175-KOL-2007-(15-06-2012)-OTHERS.pdf

1175-KOL-2007-ASSIGNMENT.pdf

1175-KOL-2007-CORRESPONDENCE OTHERS 1.1.pdf

1175-KOL-2007-CORRESPONDENCE.pdf

1175-KOL-2007-EXAMINATION REPORT.pdf

1175-KOL-2007-FORM 18 1.1.pdf

1175-kol-2007-form 18.pdf

1175-KOL-2007-FORM 3.pdf

1175-KOL-2007-FORM 5.pdf

1175-KOL-2007-GPA 1.1.pdf

1175-KOL-2007-GPA.pdf

1175-KOL-2007-GRANTED-ABSTRACT.pdf

1175-KOL-2007-GRANTED-CLAIMS.pdf

1175-KOL-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

1175-KOL-2007-GRANTED-DRAWINGS.pdf

1175-KOL-2007-GRANTED-FORM 1.pdf

1175-KOL-2007-GRANTED-FORM 2.pdf

1175-KOL-2007-GRANTED-SPECIFICATION.pdf

1175-KOL-2007-OTHERS.pdf

1175-KOL-2007-PRIORITY DOCUMENT.pdf

1175-KOL-2007-REPLY TO EXAMINATION REPORT.pdf

1175-KOL-2007-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

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