JP4930353B2 - Cooling system - Google Patents

Description

  The present invention relates to a cooling device, and more specifically, in normal operation, the opening degree of an electronic expansion valve is adjusted based on the internal temperature of the container, and refrigerant supply control to an evaporator disposed in the container is performed. It is related with the improvement of the cooling device which makes this container the desired temperature state by performing.

  For example, in a showcase that displays and sells products in a cooled state, an evaporator is provided inside the container, and a compressor, a condenser, and an electronic expansion valve are provided outside the container. A compressor, a condenser, and an electronic expansion valve are sequentially connected by piping to constitute a cooling device that circulates the enclosed refrigerant. In such a cooling device, in the normal operation, the opening degree of the electronic expansion valve is adjusted based on the internal temperature of the container, and the refrigerant supply control to the evaporator disposed in the container is performed. The storage is brought to a desired temperature state.

  In such a cooling device, a means for detecting the temperature of the air passing around the evaporator (hereinafter also referred to as an intake air temperature sensor) and a means for detecting the temperature of the refrigerant supplied to the evaporator (hereinafter, referred to as a suction air temperature sensor). In the case of normal operation, the temperature difference between the detected temperature of the intake air temperature sensor and the detected temperature of the refrigerant temperature sensor is calculated, and the temperature difference and a preset reference value are calculated. In comparison, it is known to detect an open failure of an electronic expansion valve, that is, a failure that locks in an open state, and a closed failure, that is, a failure that locks in a closed state (for example, , See Patent Document 1).

JP 2000-274896 A

  However, in the cooling device proposed in Patent Document 1 as described above, the temperature difference between the detected temperature of the intake air temperature sensor and the detected temperature of the refrigerant temperature sensor is calculated, and the temperature difference is compared with a reference value. In order to detect a failure (open failure and closed failure) of the electronic expansion valve, there has been the following problem. That is, even if the electronic expansion valve fails, if both the detected temperature of the intake air temperature sensor and the detected temperature of the refrigerant temperature sensor change in the same way as when the electronic expansion valve is normal, the temperature of both detected temperatures The difference did not change, and there was a possibility that the electronic expansion valve was not detected as a failure, and there was a problem in reliability.

  In view of the above circumstances, an object of the present invention is to provide a cooling device that can improve the reliability of detection accuracy by detecting a failure of an electronic expansion valve satisfactorily.

In order to achieve the above object, a cooling device according to claim 1 of the present invention comprises opening degree adjusting means for adjusting the opening degree of the electronic expansion valve based on the internal temperature of the container in normal operation. In the cooling device for bringing the storage into a desired temperature state by controlling the supply of the refrigerant to the evaporator disposed in the storage by the degree adjusting means, the opening degree adjusting means includes a preset upper limit valve An opening / closing command means for giving an opening operation command or a closing operation command to the electronic expansion valve based on an internal temperature of the container within a range between an opening degree and a lower limit valve opening degree; and the opening / closing command means is an upper limit valve when the opening operation instruction to continue only given predetermined set time Runimokakawarazu the internal temperature to the effect that the opening is continuously exceeded the target temperature set in advance, the electronic expansion valve is closed While it is determined that that disabled, the switching command means target temperature Runimokakawarazu the internal temperature closing operation command continues giving only the set time of the effect that the lower limit valve opening is set in advance And a failure determination means for determining that the electronic expansion valve is in an open failure state when the voltage continues to fall .

  The cooling device according to claim 2 of the present invention is the cooling device according to claim 1 described above, wherein the opening degree adjusting means moves to a defrosting operation after a predetermined time has elapsed after the start of the normal operation. Closes the electronic expansion valve and stops the supply of the refrigerant to the evaporator, and detects the temperature of the refrigerant passing through the inlet of the evaporator among the refrigerant pipes connected to the evaporator An inlet portion refrigerant temperature detecting means, an outlet portion refrigerant temperature detecting means for detecting the temperature of the refrigerant passing through the outlet portion of the evaporator in the refrigerant pipe, and the outlet portion in the vicinity of the outlet portion. An intermediate refrigerant temperature detecting means for detecting the temperature of the refrigerant passing through the site; the inlet refrigerant temperature detecting means; the outlet refrigerant temperature detecting means; and the predetermined temperature for each predetermined time in the defrosting operation. During ~ Each temperature is detected through the refrigerant temperature detection means, and if there is at least one detected temperature higher than the previous detected temperature, the electronic expansion valve is determined to be normal, while the inlet If the temperature detected through the partial refrigerant temperature detecting means, the outlet refrigerant temperature detecting means, and the intermediate refrigerant temperature detecting means is not higher than the previous detected temperature, the electronic expansion valve is opened. Failure determination means for determining that there is a failure is provided.

  According to the present invention, the opening degree adjusting means opens the electronic expansion valve based on the internal temperature of the container within the range between the upper limit valve opening degree and the lower limit valve opening degree set in advance through the opening / closing command means. The electronic expansion valve closes and fails when a command or a closing operation command is given and the opening / closing command means that the opening / closing command means sets the upper limit valve opening through the failure determination means. On the other hand, if the open / close command means continues to give the closing operation command to the lower limit valve opening for the set time, it is determined that the electronic expansion valve has failed to open. The failure of the electronic expansion valve is judged from the relationship between the opening / closing command and the command time. Compared to the conventional case where the failure is judged by comparing the two temperatures, the electronic expansion valve Good detection of valve failure Accordingly, there is an effect that it is possible to improve the reliability of the detection accuracy.

  Exemplary embodiments of a cooling device according to the present invention will be described below in detail with reference to the accompanying drawings as appropriate.

  FIG. 1 conceptually shows the configuration of a cooling device according to an embodiment of the present invention. The cooling device illustrated here is applied to an open showcase 11 that displays and sells products stored in the storage 10 in a cooled state, and includes an evaporator 12 and an electronic expansion valve in each of the multiple open showcases 11. 13 is provided separately, and one condenser 14 and one compressor 15 are provided outside the open showcase 11. FIG. 1 shows one open showcase 11 for convenience of explanation.

  The electronic expansion valve 13 supplies the liquid refrigerant discharged from the condenser 14 to the evaporator 12 by adiabatic expansion. In the present embodiment, when an opening degree command (opening operation command and closing operation command) is given, an electronic expansion valve capable of changing the opening degree according to the opening degree command and adjusting the flow rate of the refrigerant passing therethrough 13 is applied. The compressor 15 compresses the low-temperature and low-pressure gas refrigerant discharged from the evaporator 12 and supplies it to the condenser 14 as a high-temperature and high-pressure gas refrigerant.

  In this cooling device, an evaporator 12 and an electronic expansion valve 13 provided in each open showcase 11 are connected to the condenser 14 and the compressor 15 by a refrigerant supply line 16 in a parallel manner. Is configured. That is, in this cooling device, the high-temperature and high-pressure gas refrigerant discharged from the compressor 15 is cooled in the condenser 14 to become a high-temperature and high-pressure liquid refrigerant. This high-temperature and high-pressure liquid refrigerant is adiabatically expanded by the electronic expansion valve 13 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant, and is supplied to the evaporator 12 of the container 10. The low-temperature and low-pressure gas-liquid two-phase refrigerant supplied to the evaporator 12 exchanges heat with the internal air of the storage 10 supplied by the blower fan 17 and absorbs heat to become a low-temperature and low-pressure gas refrigerant. Cool down. The low-temperature and low-pressure gas refrigerant discharged from the evaporator 12 is sucked into the compressor 15 and again becomes a high-temperature and high-pressure gas refrigerant and supplied to the condenser 14.

  Refrigerant temperature sensors 20, 21, and 22 are provided at an inlet portion, an outlet portion, and an intermediate portion of the refrigerant supply line 16 connected to the evaporator 12 in the open showcase 11, respectively. The inlet refrigerant temperature sensor (inlet refrigerant temperature detecting means) 20 and the outlet refrigerant temperature sensor (exit refrigerant temperature detecting means) 21 are for detecting the temperature of the refrigerant passing through the respective refrigerant supply pipes 16. The intermediate refrigerant temperature sensor (intermediate refrigerant temperature detection means) 22 detects the temperature of the refrigerant that passes through a portion close to the outlet in the evaporator 12.

  An internal temperature sensor 23 is provided inside the storage 10. The internal temperature sensor 23 detects the internal temperature of the container 10. In the present embodiment, the internal temperature sensor 23 detects the air after passing through the evaporator 12 inside the storage 10, that is, the temperature of the blown air as the internal temperature of the storage 10. Here, the internal temperature may not be the temperature of the blown air but may be a temperature detected by an internal temperature sensor (not shown) provided inside the storage 10. Or it calculated | required from the back surface temperature sensor 24 (reference) provided in the back surface inside the storage 10, the suction temperature sensor 25 (reference) provided in the suction inlet, the blowing temperature sensor provided in the blower outlet, etc. The average air temperature (internal temperature) may be used.

  Further, the cooling device includes a valve opening degree adjusting means 30 and a failure determining means 40 as its control system.

  The valve opening adjusting means 30 adjusts the opening of the electronic expansion valve 13 when the cooling device is in a normal operation, and closes the electronic expansion valve 13 when the cooling device is in a defrosting operation described later. , A setting storage unit 31, a temperature comparison determination unit 32, a valve opening setting processing unit 33, a failure determination unit 34, and a time measurement unit 35.

  The setting storage unit 31 stores data and programs necessary for the valve opening degree adjusting means 30 to perform various processing contents to be described later, and sets and stores the target temperature of the storage 10 in advance. It is.

  The temperature comparison determination unit 32 compares the internal temperature of the storage 10 detected by the internal temperature sensor 23 with the target temperature of the storage 10 stored in the setting storage unit 31, and the internal temperature is less than the target temperature. In addition, it is determined whether the internal temperature exceeds the target temperature when the internal temperature is not lower than the target temperature.

  The valve opening setting processing unit 33 is an opening / closing command means for setting an opening of the electronic expansion valve 13 by giving an opening command (an opening operation command and a closing operation command) to the electronic expansion valve 13. More specifically, when the cooling device is in normal operation, the valve opening setting processing unit 33 sets the upper limit valve opening (the upper limit value of the valve opening) and the lower limit valve opening (the valve opening of the valve opening) that are set in advance. Within the range of the lower limit value), based on the comparison result between the detection result (detected temperature) of the internal temperature sensor 23 and the target temperature of the storage 10 stored in the setting storage unit 31, the opening degree of the electronic expansion valve 13 is An opening is set by giving a command. Specifically, when the detected internal temperature is lower than the target temperature, an opening operation command is given to increase the valve opening, while when the detected internal temperature exceeds the target temperature, a closing operation command is given. The valve opening is reduced, and when the detected internal temperature matches the target temperature, the valve opening is maintained.

  In addition, the valve opening setting processing unit 33, when the cooling device is in the defrosting operation to be described later, is an opening command (a closing operation command) indicating that the electronic expansion valve 13 is fully closed (closed state). ) To set the opening.

  The failure determination unit 34 is a failure determination unit that determines that the electronic expansion valve 13 is open failure, that is, a failure that locks in the opened state, and a closed failure, that is, a failure that locks in the closed state. is there. More specifically, the failure determination unit 34 starts time measurement through the time measurement unit 35 when the valve opening setting processing unit 33 gives an opening operation command indicating that the upper limit valve opening is set. The internal temperature continues to exceed the target temperature even when the set time reaches the preset set time, i.e., the opening operation command for setting the upper limit valve opening is continued for the set time. Alternatively, when the blown air temperature continues to rise, it is determined that the electronic expansion valve 13 has a closed failure. On the other hand, when the valve opening setting processing unit 33 gives a closing operation command to the effect that the lower limit valve opening is set, time measurement is started through the time measuring unit 35, and the measured time is set in a predetermined time. However, the internal temperature continues to fall below the target temperature or the blown air temperature continues to fall, even though the closing operation command for setting the lower limit valve opening is continued for the set time. If the electronic expansion valve 13 is in the open state, it is determined that the electronic expansion valve 13 has an open failure.

  The failure determination means 40 determines a failure of the electronic expansion valve 13 when the cooling device is in the defrosting operation, and includes various information storage units 41, an input processing unit 42, a timer unit 43, and a failure determination unit 44. Yes.

  The various information storage unit 41 stores data and programs necessary for the failure determination means 40 to perform various processing contents to be described later, and data input through the input processing unit 42 (inlet refrigerant temperature sensor 20, intermediate Temperature data detected by the partial refrigerant temperature sensor 22 and the outlet refrigerant temperature sensor 21).

  The input processing unit 42 performs input processing on each temperature data (detected temperature) detected through the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21. More specifically, temperature data detected through the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21 is input at predetermined time intervals (for example, one minute). is there. The timer unit 43 is for measuring the set time.

  The failure determination unit 44 determines whether or not the electronic expansion valve 13 is normal based on the detected temperatures that are input through the input processing unit 42 and stored in the various information storage units 41, that is, the electronic expansion valve 13 is normal. Or, it is determined whether an open failure has occurred. More specifically, when there is at least one of the detected temperatures that is higher than the previous (most recent previous) detected temperature from the defrosting operation to the pull-down (cooling operation), While it is determined that the electronic expansion valve 13 is normal, there is no one that is higher than the previous detected temperature, that is, there is no one that is higher than the previous detected temperature. It is determined that the expansion valve 13 has an open failure.

  Next, the operation of the cooling device will be described. Here, the cooling device pulls down (cooling operation) for a predetermined time or until the internal temperature of the container 10 reaches a predetermined temperature (target temperature), and then performs a normal operation, and the normal operation reaches a predetermined time. After (more specifically, after a preset cycle time (for example, 6 hours) has elapsed since the start of the defrosting operation), the supply of the refrigerant to the evaporator 12 is stopped and the defrosting operation is performed. . After this defrosting operation, the cycle of pulling down again and then performing the normal operation is repeated. That is, the cooling device repeats a cycle of pull-down → normal operation → defrost operation.

  In the normal operation, the valve opening degree adjusting means 30 constituting the cooling device performs a valve opening degree adjusting process. FIG. 2 is a flowchart showing the contents of the valve opening degree adjusting process performed by the valve opening degree adjusting means 30 shown in FIG.

  The valve opening degree adjusting means 30 in the valve opening degree adjusting process detects the internal temperature of the container 10 in the open showcase 11 through the internal temperature sensor 23 (step S101).

  The valve opening degree adjusting means 30 that has detected the internal temperature of the container 10 compares and determines whether or not the internal temperature is lower than the target temperature stored in the setting storage unit 31 through the temperature comparison determination unit 32 (step S102). ) When it is determined that the internal temperature is lower than the target temperature (step S102: Yes), the valve opening degree closing process is performed (step S110). Such valve opening closing processing will be described later.

  On the other hand, when it is determined through the temperature comparison determination unit 32 that the internal temperature is not lower than the target temperature but exceeds the target temperature (step S102: No, step S103: Yes), the valve opening degree opening process is performed. (Step S130). This valve opening opening process will be described later.

  By the way, when it is determined through the temperature comparison determination unit 32 that the internal temperature is not lower than the target temperature and does not exceed the target temperature (step S102: No, step S103: No), that is, the internal temperature becomes the target temperature. If it is determined that they are equal, the valve opening degree adjusting means 30 gives a maintenance command to the electronic expansion valve 13 through the valve opening degree setting processing unit 33 to maintain the valve opening degree (step S104), and then performs the procedure. Return and end the current process.

  FIG. 3 is a flowchart showing the contents of the valve opening closing process shown in FIG. The valve opening degree adjusting means 30 in the valve opening degree closing process, that is, when the internal temperature is determined to be lower than the target temperature in step S102, the valve opening degree adjusting means 30 passes the electronic expansion valve through the valve opening degree setting processing unit 33. A closing operation command for closing a predetermined pulse is given to 13 (step S111). The valve opening degree adjusting means 30 that has given the closing operation command detects the internal temperature of the storage 10 through the internal temperature sensor 23 (step S112), and then the internal temperature is set and stored in the setting storage unit 31 through the temperature comparison determination unit 32. It is determined whether or not the temperature is lower than the target temperature stored in (step S113). When it is determined that the internal temperature is not lower than the target temperature, that is, when the internal temperature is equal to or higher than the target temperature (step S113: No), the procedure is returned without performing the processing described later, and the current valve opening degree is closed. End the process.

  On the other hand, when it is determined that the internal temperature is lower than the target temperature, and the closing operation command in step S111 is not a closing operation command at the lower limit valve opening (step S113: Yes, step S114: No), the above The processes in steps S111 to S113 are repeatedly performed at a constant time period. That is, in the valve opening degree closing process, when the internal temperature (detected temperature) of the container 10 is lower than the target temperature even in the valve opening degree closing process, the valve opening degree adjusting means 30 is more than the closing action command. A new closing operation command for reducing the opening is given, and the process is repeated until the internal temperature (detected temperature) becomes equal to or higher than the target temperature. When a closing operation command is given at the lower limit valve opening (step S114: Yes), an open failure determination process is performed (step S120).

  FIG. 4 is a flowchart showing the contents of the open failure determination process shown in FIG. The valve opening degree adjusting means 30 in the open failure determination process, that is, when the closing operation command at the lower limit valve opening degree is given through the valve opening degree setting processing part 33, the valve opening degree adjusting means 30 is the time measuring part 35. Time measurement is started through (step S121), the internal temperature of the container 10 is detected through the internal temperature sensor 23 (step S122), and the internal temperature is then stored in the setting storage unit 31 through the temperature comparison determination unit 32. Whether the temperature is lower than the target temperature to be compared is determined (step S123). When it is determined that the internal temperature is not lower than the target temperature, that is, when the internal temperature is equal to or higher than the target temperature (step S123: No), the time measurement is reset by the time measuring unit 35 (step S124), and processing described later The procedure is returned without performing the above, and the current open failure determination process is terminated.

  On the other hand, when it is determined that the internal temperature is lower than the target temperature (step S123: Yes), the valve opening degree adjusting unit 30 stores the time measurement by the time measurement unit 35 in the setting storage unit 31 through the failure determination unit 34. It is determined whether or not a predetermined set time has elapsed (step S125). When the set time has not elapsed (step S125: No), the valve opening degree adjusting means 30 repeats the processing of step S122 to step S125 at a constant time period, and when the set time has elapsed, that is, the valve The internal temperature continues to fall below the target temperature, or the blown air temperature falls, even though the opening setting processing unit 33 continues to give a closing operation command to the lower limit valve opening for the set time. If it continues (step S125: Yes), it is determined that an open failure has occurred (step S126), the fact is notified through a notifying means (not shown), and then the procedure is returned to the current process ( The open failure determination process) is terminated. Further, the supply of the refrigerant may be stopped by closing an electromagnetic valve (not shown).

  As a result of carrying out such an open failure determination process, the procedure is returned as shown in FIG. 3 to complete the valve opening closing process, whereby the procedure is returned as shown in FIG. 2 to adjust the valve opening. End the process.

  FIG. 5 is a flowchart showing the contents of the valve opening opening process shown in FIG. When the valve opening degree adjusting means 30 in the valve opening degree opening process determines that the internal temperature exceeds the target temperature in step S103, the valve opening degree adjusting means 30 passes through the valve opening degree setting processing section 33. An opening operation command for opening a predetermined pulse is given to the electronic expansion valve 13 (step S131). The valve opening degree adjusting means 30 that has given the opening operation command detects the internal temperature of the storage 10 through the internal temperature sensor 23 (step S132), and then the internal temperature is set and stored in the setting storage unit 31 through the temperature comparison determination unit 32. It is determined whether or not the target temperature stored in is exceeded (step S133). If it is determined that the internal temperature does not exceed the target temperature, that is, if the internal temperature is equal to or lower than the target temperature (step S133: No), the procedure is returned without performing the processing described later, and the current valve opening is performed. The opening process is terminated.

  On the other hand, when it is determined that the internal temperature exceeds the target temperature, and the opening operation command in step S131 is not an opening operation command at the upper limit valve opening (step S133: Yes, step S134: No) ), Steps S131 to S133 are repeatedly performed at regular intervals. That is, in the valve opening degree opening process, if the internal temperature (detected temperature) of the storage case 10 exceeds the target temperature in the valve opening degree opening process, the valve opening degree adjusting means 30 determines whether the opening degree instruction means 30 Also, a new opening operation command for further increasing the opening degree is given, and the operation is repeated until the internal temperature (detected temperature) becomes equal to or lower than the target temperature. When an opening operation command is given at the upper limit valve opening (step S134: Yes), a closed failure determination process is performed (step S140).

  FIG. 6 is a flowchart showing the contents of the closed failure determination process shown in FIG. The valve opening degree adjusting means 30 in the closing failure determination process, that is, when the opening operation command at the upper limit valve opening degree is given through the valve opening degree setting processing part 33, the valve opening degree adjusting means 30 is the time measuring part 35. Time measurement is started through (step S141), the internal temperature of the storage 10 is detected through the internal temperature sensor 23 (step S142), and then the internal temperature is stored in the setting storage unit 31 through the temperature comparison determination unit 32. It is determined whether or not the target temperature is exceeded (step S143). When it is determined that the internal temperature exceeds the target temperature, that is, when the internal temperature is equal to or lower than the target temperature (step S143: No), the time measurement is reset by the time measuring unit 35 (step S144), which will be described later. The procedure is returned without performing the process to complete the current closed fault determination process.

  On the other hand, when it is determined that the internal temperature exceeds the target temperature (step S143: Yes), the valve opening degree adjusting unit 30 is configured to measure the time by the time measuring unit 35 through the failure determining unit 34. It is determined whether or not a predetermined set time stored in the elapses (step S145). When the set time has not elapsed (step S145: No), the valve opening degree adjusting means 30 repeats the processing of step S142 to step S145 at a constant period, and when the set time has elapsed, that is, the valve is opened. The internal temperature continues to exceed the target temperature or the blown air temperature continues to rise, even though the degree setting processing unit 33 continues to give the opening operation command to the upper limit valve opening for the set time. If this is the case (step S145: Yes), it is determined that there is a closed failure (step S146), that effect is notified through notifying means (not shown), and then the procedure is returned to the current process (closed). The failure determination process is terminated. Further, the supply of the refrigerant may be stopped by closing a solenoid valve (not shown).

  As a result of such a closed failure determination process, the procedure is returned as shown in FIG. 5 to complete the valve opening opening process, thereby returning the procedure and adjusting the valve opening as shown in FIG. End the process.

  When the valve opening degree adjusting process described above is summarized, the valve opening degree adjusting means 30 passes through the valve opening degree setting processing part 33 when the internal temperature of the container 10 is lower than the target temperature stored in the setting storage part 31. A closing operation command is given to the electronic expansion valve 13. As a result, if the internal temperature of the storage 10 becomes equal to or higher than the target temperature, the process is terminated. On the other hand, if the internal temperature of the storage 10 is still lower than the target temperature, a closing operation command for further reducing the valve opening is issued. Then, a new closing operation command is continuously given in such a manner that the valve opening is gradually reduced until the internal temperature of the container 10 becomes equal to or higher than the target temperature.

  Then, when a closing operation command for giving a preset lower limit valve opening is given, time measurement is started, and when the measurement time reaches a predetermined set time, that is, the lower limit valve opening. The electronic expansion valve 13 is used when the internal temperature continues to fall below the target temperature or the blown air temperature continues to decrease, even though the closing operation command to the extent is continued for the set time. Is determined to have an open failure.

  On the other hand, when the internal temperature of the container 10 exceeds the target temperature stored in the setting storage unit 31, the valve opening degree adjusting unit 30 instructs the electronic expansion valve 13 to open through the valve opening setting processing unit 33. give. As a result, if the internal temperature of the storage 10 becomes equal to or lower than the target temperature, the process is terminated. On the other hand, if the internal temperature of the storage 10 still exceeds the target temperature, an opening operation command for further increasing the valve opening degree. And a new closing operation command is continuously given in such a manner that the valve opening is gradually increased until the internal temperature of the container 10 becomes equal to or lower than the target temperature.

  Then, when an opening operation command for giving a preset upper limit valve opening degree is given, time measurement is started, and when the measurement time reaches a predetermined set time, that is, the upper limit valve opening time is reached. The electronic expansion valve 13 is used when the internal temperature continues to exceed the target temperature or the blown air temperature continues to rise, even though the opening operation command to the extent is continued for the set time. Is determined to have a closed failure.

  The cooling device that has performed the valve opening adjustment process as described above in the normal operation evaporates after the normal operation time reaches a predetermined time, that is, after a preset cycle time has elapsed from the start of the defrosting operation. The supply of the refrigerant to the vessel 12 is stopped and the defrosting operation is performed.

  In the case of the defrosting operation, the valve opening degree adjusting means 30 constituting the cooling device gives a closing operation command to the electronic expansion valve 13 through the valve opening degree setting processing unit 33 so as to be in a fully closed state (closed state). On the other hand, the failure determination means 40 performs failure determination processing. FIG. 7 is a flowchart showing the contents of the failure determination process performed by the failure determination means shown in FIG.

  In the failure determination process, the failure determination means 40 inputs each of the inlet refrigerant temperature (hereinafter also referred to as T1), the intermediate refrigerant temperature (hereinafter also referred to as T2), and the outlet refrigerant temperature (hereinafter also referred to as T3). (Step S200).

  FIG. 8 is a flowchart showing the contents of the input part refrigerant temperature, intermediate part refrigerant temperature, and outlet part refrigerant temperature input processes (hereinafter also referred to as T1, T2, T3 input processes) shown in FIG.

  In the T1, T2, and T3 input processes, the failure determination means 40 includes the inlet refrigerant temperature T1, the intermediate refrigerant temperature T2, and the outlet through the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21. The refrigerant temperature T3 is detected (step S201), and the refrigerant temperatures T1, T2, and T3 are input through the input processing unit 42 (step S202). Thereafter, the failure determination means 40 stores each refrigerant temperature input through the input processing unit 42 in the various information storage units 41 (step S203), returns the procedure, and ends the current process.

  Although not clearly shown in the figure, the failure determination means 40 starts measuring time after storing each T1, T2, T3 through the timer unit 43, and sets the measurement time stored in the various information storage unit 41 in advance ( When, for example, 1 minute) is reached, the T1, T2, and T3 input processes are repeated. That is, the failure determination means 40 performs T1, T2, and T3 input processing for inputting and storing the refrigerant temperatures T1, T2, and T3 detected every set time (for example, 1 minute) during the defrosting operation. It is repeating. As a result of repeating such processing, the refrigerant temperatures T1, T2, T3 as shown in FIG. In FIG. 9, t0 is the defrosting operation start time, t1 is the time 1 minute after the start of the defrosting operation, t2 is the time 1 minute after t1, and t3 is the time 1 minute after t2. Show. Moreover, the failure determination means 40 is repeatedly performed during the period from when the defrosting operation is started until the pull-down (cooling operation) is started, or for a predetermined time (for example, 10 minutes).

  The failure determination means 40 that has performed such T1, T2, T3 input processing, through the failure determination unit 44, increases the refrigerant temperature T1 detected this time higher than the refrigerant temperature T1 ′ detected last time (the latest previous time). Whether the refrigerant temperature T2 is higher than the refrigerant temperature T2 'detected last time (the latest previous time), and the refrigerant temperature T3 is higher than the refrigerant temperature T3' detected last time (the latest previous time). It is confirmed whether or not it has risen (step S211, step S212, step S213). If any one of these has risen, it is determined that the electronic expansion valve 13 is normal (step S214), Thereafter, the procedure is returned to end the current process.

  On the other hand, when all of the refrigerant temperatures T1, T2, and T3 are not higher than the previous refrigerant temperatures T1 ′, T2 ′, and T3 ′ (step S211: No, step S212: No, step S213: No) Then, the failure determination means 40 determines that the electronic expansion valve 13 has an open failure through the failure determination unit 44 (step S215), and then returns the procedure to end the current process.

  That is, the failure determination means 40 passes the refrigerant through the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21 every predetermined time (every minute) predetermined in the defrosting operation. When at least one of the detected refrigerant temperatures is higher than the previously detected refrigerant temperature, the electronic expansion valve 13 is determined to be normal while the inlet refrigerant temperature sensor 20 is detected. When the refrigerant temperature detected through the intermediate refrigerant temperature sensor 22 and the outlet refrigerant temperature sensor 21 is not higher than the refrigerant temperature detected last time, the electronic expansion valve 13 is malfunctioning. It is judged.

  The cooling device that has performed the defrosting operation in this manner performs pull-down after that, and performs normal operation again after the pull-down.

  As described above, according to the cooling device in the embodiment of the present invention, in the normal operation, the valve opening adjusting means 30 opens the valve opening setting processing unit 33 to the upper limit valve opening. Electronic expansion through the failure determination unit 34 when the internal temperature continues to exceed the target temperature or the blown air temperature continues to rise despite the command being given for a predetermined set time. While it is determined that the valve 13 is in a closed failure state, the internal temperature is the target even though the closing operation command for setting the lower limit valve opening through the valve opening setting processing unit 33 is continuously given for a set time. When the temperature continues to fall below or the blown air temperature continues to fall, it is determined that the electronic expansion valve 13 is open, so the opening command to the valve opening and its command time No seki Thus, the failure of the electronic expansion valve 13 is judged, and the failure of the electronic expansion valve 13 is detected better than the conventional case where the failure is judged by comparing and calculating two temperatures. The reliability of detection accuracy can be improved.

  Further, according to the cooling device, in the case of the defrosting operation, the failure determination means 40 has the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21 at predetermined time intervals. Each refrigerant temperature T1, T2, T3 is detected, and at least one refrigerant temperature T1, T2, T3 is higher than the previously detected refrigerant temperature T1 ′, T2 ′, T3 ′. While it is determined that the electronic expansion valve 13 is normal, the refrigerant temperatures T1, T2, T3 detected through the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21 are the refrigerant temperatures T1 detected last time. When there is nothing higher than ', T2', T3 ', it is determined that the electronic expansion valve 13 is in an open failure state. Not, it is possible to satisfactorily detect the failure of the electronic expansion valve 13 even when the defrosting operation.

  In particular, in the cooling device according to the present embodiment, the failure determination means 40 uses the three refrigerant temperatures T1, T2, and T3 detected through the inlet refrigerant temperature sensor 20, the intermediate refrigerant temperature sensor 22, and the outlet refrigerant temperature sensor 21. Since the normal or open failure of the electronic expansion valve 13 is determined based on this, it is possible to determine more reliably. More specifically, if only the normal or open failure of the electronic expansion valve 13 is determined, as is apparent from FIG. 9, the intermediate refrigerant temperature sensor 22 having a relatively stable temperature distribution, or the outlet refrigerant. The refrigerant temperatures T2 and T3 detected by the temperature sensor 21 are also possible. However, the temperature difference for each time is relatively small, and in some cases, the temperature difference is infinitely small. Therefore, there is a possibility that normal or open failure of the electronic expansion valve 13 cannot be accurately determined. On the other hand, the refrigerant temperature T1 detected by the inlet refrigerant temperature sensor 20 has a portion where the temperature distribution is unstable, but the temperature difference per predetermined time is relatively large, and the temperature difference can be measured. Therefore, the failure of the electronic expansion valve 13 can be detected well more reliably based on the detection results of these three sensors. Further, immediately after the start of the defrosting operation, since the low pressure is temporarily lowered, it is confirmed that the refrigerant temperature T1 detected by the inlet refrigerant temperature sensor 20 is once lowered as shown in FIG. However, during the elapsed time, the temperature difference between the refrigerant temperatures T2 and T3 detected every predetermined time by the intermediate refrigerant temperature sensor 22 and the outlet refrigerant temperature sensor 21 is sufficiently large. Therefore, there is no possibility of erroneous determination at the elapsed time.

  As described above, the cooling device according to the present invention is useful for cooling an open showcase container.

It is the conceptual diagram which showed notionally the structure of the cooling device which is embodiment of this invention. It is a flowchart which shows the content of the valve opening degree adjustment process which the valve opening degree adjustment means shown in FIG. 1 implements. It is a flowchart which shows the content of the valve opening closing process shown in FIG. It is a flowchart which shows the content of the open failure determination process shown in FIG. It is a flowchart which shows the content of the valve opening opening process shown in FIG. It is a flowchart which shows the content of the closed fault judgment process shown in FIG. It is a flowchart which shows the content of the failure determination process which the failure determination means shown in FIG. 1 implements. It is a flowchart which shows the content of the input process of the inlet part refrigerant | coolant temperature shown in FIG. 7, an intermediate part refrigerant | coolant temperature, and an outlet part refrigerant | coolant temperature. It is a graph which shows the relationship between the elapsed time of each refrigerant temperature, and temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Container 11 Open showcase 12 Evaporator 13 Electronic expansion valve 14 Condenser 15 Compressor 16 Refrigerant supply line 17 Blower fan 20 Inlet part refrigerant | coolant temperature sensor 21 Outlet part refrigerant | coolant temperature sensor 22 Intermediate part refrigerant | coolant temperature sensor 23 Internal temperature sensor DESCRIPTION OF SYMBOLS 30 Valve opening degree adjustment means 31 Setting memory | storage part 32 Temperature comparison judgment part 33 Valve opening degree setting process part 34 Failure judgment part 35 Time measurement part 40 Failure judgment means 41 Various information storage part 42 Input processing part 43 Timer part 44 Fault judgment part

Claims (2)

In normal operation, it is provided with an opening degree adjusting means for adjusting the opening degree of the electronic expansion valve based on the internal temperature of the storage case, and the supply control of the refrigerant to the evaporator disposed in the storage case by the opening degree adjusting means. In the cooling device that brings the container into a desired temperature state by performing,
The opening degree adjusting means is
An opening / closing command means for giving an opening operation command or a closing operation command to the electronic expansion valve based on an internal temperature of the container within a range between a preset upper limit valve opening and a lower limit valve opening;
When said switching command means it is continuously exceeded the target temperature opening operation instruction to continue only given predetermined set time Runimokakawarazu the internal temperature is preset to the effect that the upper limit valve opening, the one that electronic expansion valve is determined that that closure failure, the switching command means lower valve Runimokakawarazu the internal temperature closing operation command continues giving only the set time of the effect that the opening is preliminarily And a failure determination means for determining that the electronic expansion valve is open-failed when the set temperature continues to fall below a set target temperature . The opening degree adjusting means closes the electronic expansion valve and stops the supply of the refrigerant to the evaporator when a predetermined time elapses after the start of the normal operation and the defrosting operation is started. Is,
Inlet refrigerant temperature detecting means for detecting the temperature of the refrigerant passing through the inlet of the evaporator among the refrigerant pipes connected to the evaporator;
Outlet refrigerant temperature detecting means for detecting the temperature of the refrigerant passing through the outlet of the evaporator in the refrigerant pipe;
An intermediate refrigerant temperature detecting means for detecting the temperature of the refrigerant passing through a portion close to the outlet in the evaporator;
Each temperature is detected through the inlet portion refrigerant temperature detecting means, the outlet portion refrigerant temperature detecting means, and the intermediate portion refrigerant temperature detecting means at predetermined time intervals determined in advance in the defrosting operation, and the detected temperature is the previous temperature. If there is at least one that is higher than the detected temperature, the electronic expansion valve is determined to be normal, while the inlet refrigerant temperature detecting means, the outlet refrigerant temperature detecting means, and the intermediate part A failure determining means for determining that the electronic expansion valve is in an open failure state when there is no one whose temperature detected through the refrigerant temperature detecting means is higher than the previous detected temperature. The cooling device according to claim 1, wherein

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