JP5789756B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus in which a refrigerant circuit is configured by a compressor, a condenser, a receiver tank, a throttle means, and an evaporator.

  Conventionally, in a store such as a supermarket or a convenience store, a plurality of showcases (cooling devices) for displaying and selling products have been installed in the store floor (indoor). Each showcase is provided with an evaporator and connected to a refrigerator installed outdoors (see, for example, Patent Document 1). As a result, the compressor, the condenser, the receiver tank provided in the refrigerator, the throttling means, the evaporator, and the like provided on each showcase side are sequentially connected in an annular manner by the piping, thereby forming a refrigerant circuit. A predetermined amount of refrigerant is sealed in the refrigerant circuit.

  When the compressor is operated, the refrigerant is compressed into a high-temperature and high-pressure gas state and flows into the condenser. In this condenser, the refrigerant dissipates heat and is condensed and liquefied, and then temporarily stored in the receiver tank, and then decompressed by the throttling means, and then supplied to the evaporator. In this evaporator, the refrigerant evaporates, and at that time, the refrigerant absorbs heat from the surroundings and exhibits a cooling action.

JP 2005-315495 A

  As described above, since the refrigerator installed outside the room (inside or outside the sales floor or outdoors) and the showcase in the store are connected by refrigerant piping at the site, in welding locations, screwing parts, joints, etc. There is a high risk of refrigerant leakage. Naturally, when the refrigerant leaks, the cooling capacity of the refrigeration apparatus decreases, which causes deterioration of the products displayed in the storage chamber, and when a large amount of leak occurs, the global environment is greatly affected. In particular, when HFC is employed as the refrigerant, there is a problem that it is difficult to find a refrigerant leak because a receiver tank is provided to enclose a relatively large amount of refrigerant.

  Therefore, when the user determines that the cooling in the storage chamber has become extremely bad in the past, each location is individually confirmed using a leak detector, gas leak detection spray, etc., to estimate whether the refrigerant leak is the cause or not. However, such a detection method requires a great deal of labor and time, and during that time, the product deteriorates and the customer is troubled.

  The present invention has been made to solve the conventional technical problems, and an object of the present invention is to provide a refrigeration apparatus capable of detecting refrigerant leakage quickly, easily and accurately.

  In order to solve the above-described problems, a refrigeration apparatus according to the present invention includes a compressor, a condenser, a receiver tank, a throttling means, and an evaporator. Control means for detecting refrigerant leakage is provided. The control means divides the refrigerant circuit into a plurality of areas in a normal operation state, and the density of refrigerant in the area from the temperature and pressure of the area necessary for detecting refrigerant leakage. The refrigerant amount is calculated by multiplying the refrigerant density by the volume of the region, and a preliminary detection operation for periodically determining refrigerant leakage from the refrigerant circuit based on the calculated refrigerant amount is performed. When the preliminary detection operation determines that the refrigerant leaks, a pump-down operation for collecting the refrigerant in the receiver tank is performed, the refrigerant circuit is divided into a plurality of areas, and the temperature of the area necessary for detecting the refrigerant leak and From pressure The refrigerant density in the region is calculated, the refrigerant amount is calculated by multiplying the refrigerant density by the volume of the region, and a detailed detection operation for determining refrigerant leakage from the refrigerant circuit based on the calculated refrigerant amount is executed. It is characterized by that.

  The invention of claim 2 is characterized in that, in the above invention, the control means has a mode for periodically executing the detailed detection operation regardless of whether or not the refrigerant leakage is determined in the preliminary detection operation.

  The invention of claim 3 is characterized in that, in each of the above inventions, the control means defrosts the evaporator when performing the detailed detection operation.

  According to a fourth aspect of the present invention, in each of the above-mentioned inventions, the control means includes a first region in the region from the outlet of the evaporator to the suction side of the compressor, and a second region in the region from the compressor to the inlet of the condenser. Area, the third area in the condenser, the area from the outlet of the condenser to the inlet of the receiver tank, the fourth area, the fifth area in the receiver tank, and the outlet from the receiver tank of the evaporator. The refrigerant circuit is divided into a region up to the inlet as a sixth region and the inside of the evaporator as a seventh region.

  According to a fifth aspect of the present invention, in the above invention, the control means calculates refrigerant amounts in the first region, the second region, the fourth region, the fifth region, and the sixth region, The refrigerant leakage is determined by comparing a value subtracted from the initial refrigerant charging amount with a reference value related to the refrigerant amount in the third region and the seventh region.

  According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the control means calculates the refrigerant amount in the first region, the second region, the fourth region, the fifth region, and the sixth region. Then, by subtracting these from the initial refrigerant charging amount, the refrigerant amounts in the third region and the seventh region are calculated, and the refrigerant densities in the third region and the seventh region are calculated. The refrigerant leakage is determined by comparing the refrigerant amount in the third region obtained from the refrigerant density ratio with a reference value relating to the refrigerant amount in the third region.

  According to a seventh aspect of the present invention, in the above invention, the control means uses an average value of the inlet and outlet temperatures of the condenser as the temperature for calculating the refrigerant density in the third region, and the refrigerant density in the seventh region. The average value of the temperatures at the inlet and outlet of the evaporator is used as the temperature for calculating the value.

According to an eighth aspect of the present invention, there is provided a receiver tank refrigerant amount detecting means for detecting a liquid level in the receiver tank according to the fourth to seventh aspects of the invention, and the control means is a liquid level in the receiver tank. Is the volume of the fifth region, and the amount of refrigerant in the receiver tank is calculated based on the volume, temperature and pressure.

According to a ninth aspect of the present invention, in the fourth to eighth aspects of the present invention, the control means includes an initial refrigerant filling amount, and at least a first region, a second region, a fourth region, a fifth region, And means for recording the volume of the sixth region.

  According to a tenth aspect of the present invention, in each of the above-mentioned inventions, the control means includes means for storing the temperature and pressure of each region at the start of operation, or the reference values of these and the preliminary detection operation and the detailed detection operation. It is characterized by that.

  The invention of claim 11 is characterized in that, in each of the above inventions, the control means issues a predetermined alarm when it is determined that the refrigerant leaks in the detailed detection operation.

  According to the present invention, the refrigerant circuit is constituted by the compressor, the condenser, the receiver tank, the throttle means, and the evaporator, and the control means for detecting refrigerant leakage from the refrigerant circuit. The control means divides the refrigerant circuit into a plurality of regions in a normal operation state, calculates the refrigerant density in the region from the temperature and pressure of the region necessary for detection of refrigerant leakage, and determines the refrigerant density A refrigerant amount is calculated by multiplying the volume of the region, and a preliminary detection operation for determining refrigerant leakage from the refrigerant circuit based on the calculated refrigerant amount is periodically executed. If determined, a pump-down operation for collecting the refrigerant in the receiver tank is executed, the refrigerant circuit is divided into a plurality of areas, and the refrigerant density in the area is calculated from the temperature and pressure of the area necessary for detecting refrigerant leakage. Calculate the cold Calculated in the preliminary detection operation by calculating the refrigerant amount by multiplying the density by the volume of the region, and performing a detailed detection operation for determining refrigerant leakage from the refrigerant circuit based on the calculated refrigerant amount. The refrigerant leakage from the refrigerant circuit can be detected quickly and easily by comparing the refrigerant amount with the refrigerant amount calculated before that or the reference value.

  Then, when it is determined that the refrigerant leaks by the preliminary detection operation, the detailed detection operation accompanied by the pump-down operation is performed, so that the refrigerant that has fallen into the evaporator or the like can also be collected and determined. It becomes possible to minimize the stagnation refrigerant in the unclear area and to reduce the error.

  Therefore, it is determined whether or not refrigerant leakage is suspected by the preliminary detection operation that is periodically performed in the normal operation state, and only when it is determined that the refrigerant is leaking, by performing the detailed detection operation with the pump down operation, The influence on the normal cooling operation can be minimized, and highly accurate refrigerant leakage detection can be realized.

  According to the invention of claim 2, in the above invention, the control means has a mode for periodically executing the detailed detection operation regardless of whether or not the refrigerant leakage is determined in the preliminary detection operation. Thus, the detailed detection operation can be performed to realize highly accurate refrigerant leakage detection.

  In particular, as in the third aspect of the invention, when the detailed detection operation is performed, the control means performs defrosting of the evaporator and performs a pump-down operation, whereby the refrigerant in the evaporator is sucked, and the evaporator As the temperature increases, efficient defrosting and refrigerant leakage determination can be performed by performing defrosting that similarly increases the temperature of the evaporator.

  According to the invention of claim 4, in each of the above-mentioned inventions, the control means sets the region from the outlet of the evaporator to the suction side of the compressor as the first region and the region from the compressor to the inlet of the condenser as the first region. The second region, the third region in the condenser, the region from the condenser outlet to the receiver tank inlet is the fourth region, the receiver tank is evaporated in the fifth region, and the receiver tank outlet is evaporated. The refrigerant circuit is divided into a sixth area as the area up to the inlet of the evaporator and a seventh area as the inside of the evaporator. It is possible to calculate the refrigerant amount separately from the region where it is difficult to grasp the state. Thereby, the determination accuracy of refrigerant leakage can be improved.

  According to invention of Claim 5, in the said invention, a control means calculates the refrigerant | coolant amount of a 1st area | region, a 2nd area | region, a 4th area | region, a 5th area | region, and a 6th area | region, A value obtained by subtracting these from the initial refrigerant charging amount and a reference value related to the refrigerant amount in the third region and the seventh region are compared to determine refrigerant leakage, and in the condenser corresponding to the third region and In the evaporator corresponding to the seventh region, it is difficult to grasp the state of the internal refrigerant and the capacity of itself, but the first, second, fourth, fifth, and sixth regions are determined from the initial refrigerant charging amount. The current value of the third and seventh areas is grasped by the value obtained by subtracting the refrigerant amount, and the refrigerant leakage in the refrigerant circuit is detected quickly and easily by comparing the current value with these reference values. Will be able to.

  According to a sixth aspect of the present invention, in the fourth aspect of the invention, the control means includes the first region, the second region, the fourth region, the fifth region, and the refrigerant amount in the sixth region. Is calculated by subtracting these from the initial refrigerant charging amount and calculating the refrigerant amount in the third region and the seventh region, and calculating the refrigerant density in the third region and the seventh region. By comparing the refrigerant amount in the third region obtained from the ratio of the respective refrigerant densities with the reference value relating to the refrigerant amount in the third region, and determining the refrigerant leakage, the region in which the state of the refrigerant is not known is determined. By specifying only the third region and comparing it with the reference value, it is possible to further improve the accuracy of refrigerant leakage detection.

  In particular, in the present invention, by performing the pump-down operation in the detailed detection operation, the amount of refrigerant in the evaporator corresponding to the seventh region is almost eliminated, so that the third region can be obtained with high accuracy. The amount of refrigerant can be specified. Therefore, the accuracy of refrigerant leakage detection can be further increased.

  According to the invention of claim 7, in the above invention, the control means uses the average value of the inlet and outlet temperatures of the condenser as the temperature for calculating the refrigerant density in the third region, By using the average value of the inlet and outlet temperatures of the evaporator as the temperature for calculating the refrigerant density, the refrigerant density in the condenser corresponding to the third region and the evaporation corresponding to the seventh region are accurately obtained. It becomes possible to acquire the refrigerant density in the chamber. Thereby, a highly accurate refrigerant | coolant leak detection is realizable.

According to an eighth aspect of the present invention, in the fourth to seventh aspects of the present invention, there is provided a receiver tank refrigerant amount detecting means for detecting a liquid level in the receiver tank, and the control means is a liquid in the receiver tank. By calculating the amount of refrigerant in the receiver tank based on the volume, temperature, and pressure with the surface level as the volume of the fifth region, the amount of refrigerant in the receiver tank can be obtained with higher accuracy. High refrigerant leakage detection can be realized.

According to the invention of claim 9, in the invention of claims 4 to 8 , the control means includes the initial refrigerant filling amount, and at least the first area, the second area, the fourth area, the fifth area, By storing means for recording the volume of the area and the sixth area, the initial refrigerant filling amount and the volumes of the first, second, fourth, fifth and sixth areas are stored, By calculating the amount of refrigerant in each region from the volume of each region and the refrigerant density in these regions calculated from the temperature and pressure of each region and comparing it with the initial refrigerant charging amount, Refrigerant leakage detection can be realized.

  According to the invention of claim 10, in each of the above inventions, the control means comprises means for storing the temperature and pressure of each region at the start of operation, or the reference values of each of the preliminary detection operation and the detailed detection operation. Thus, in each of the preliminary detection operation and the detailed detection operation, it is possible to easily compare each reference value with the calculated refrigerant amount in each region and perform refrigerant leakage detection.

  According to the invention of claim 11, in each of the above-mentioned inventions, when the control means determines that the refrigerant is leaked in the detailed detection operation, the control means issues a predetermined alarm to promptly notify the user of the occurrence of the refrigerant leak. It is possible to minimize the amount of leakage by notifying, and it is possible to minimize deterioration of articles in the storage room and adverse effects on the environment.

It is a refrigerant circuit figure of the freezing apparatus in a present Example. It is a schematic block diagram of a receiver tank. It is a system block diagram of a control means. It is a flowchart which shows the registration operation | movement of initial data. It is a figure which shows each area | region. It is a flowchart which shows a refrigerant | coolant leak detection operation | movement.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus R according to an embodiment of the present invention. The refrigeration apparatus R in the present embodiment cools the storage chambers of showcases (refrigeration equipment) 5A and 5B installed in a store such as a supermarket, for example, and includes a compressor 11, a condenser 12, and a condenser blower. 13 (FIG. 3) and the like, and evaporators 15A and 15B and electromagnetic valves 16 and expansion valves (throttle means) 17A and 17B installed in a plurality of showcases 5A, 5B,. Etc. are connected by the refrigerant pipes 7 and 9 at the installation site to constitute the refrigerant circuit 1. The refrigerant circuit 1 is filled with a predetermined amount of R404A (HFC refrigerant) as an example of the refrigerant.

  The refrigerator unit 3 is installed indoors or outside the store (outdoor) other than the store, and the showcases 5A, 5B,... Are installed in the store (indoor). In the present embodiment, the refrigerator unit 3 includes two compressors 11 and 11 arranged in parallel.

  The compressor 11 is capable of controlling the rotation speed by changing the operating frequency. A refrigerant introduction pipe 22 is connected to the suction port 21 and merges at each upstream side, and an accumulator 27 and a strainer 28 are sequentially connected. Through the refrigerant pipe 9. In addition, a refrigerant discharge pipe 24 is connected to the discharge port 23 and merges on the downstream side thereof, and sequentially passes through an oil separator 26, a condenser 12, a receiver tank 30, a filter dryer 44, a moisture indicator 45, and a solenoid valve 16. Connected to the refrigerant pipe 7. Details of the receiver tank 30 will be described later.

  The oil outlet of the oil separator 26 is connected to the compressors 11 and 11 by an oil return pipe 41 via capillary tubes 42 and 42, respectively. The receiver tank 30 is connected to a pipe 43 that constitutes a liquid injection circuit. The pipe 43 branches in two directions and is connected to the inlet 25 of the compressor 11 through electromagnetic valves 44 connected in series.

  On the other hand, the showcases 5A and 5B are installed in a store or the like, and are connected in parallel to the refrigerant pipes 7 and 9, respectively. Each showcase 5A, 5B has case side refrigerant pipes 18A, 18B connected to the refrigerant pipe 7 and case side refrigerant pipes 19A, 19B connected to the refrigerant pipe 9. The case side refrigerant pipes 18A and 18B are provided with expansion valves 17A and 17B as throttle means and connected to the refrigerant inlet side of the evaporators 15A and 15B. The refrigerant outlets of the evaporators 15A and 15B are connected to the refrigerant pipe 9 via the case side refrigerant pipes 19A and 19B. The evaporators 15A and 15B are respectively adjacent to the cool air circulation fans 14A and 14B for blowing air to the evaporator.

  And as above-mentioned, the refrigerant | coolant piping 9 is connected to each compressor 11 and 11 via the refrigerant | coolant inlet tube 22, and the refrigerant | coolant piping 7 is connected to the solenoid valve 16, and thereby the refrigerant | coolant of the freezing apparatus R in a present Example. Circuit 1 is configured.

  As a result, the high-temperature and high-pressure refrigerant gas compressed by the compressor 11 flows into the condenser 12 through the oil separator 26, where it is condensed and liquefied by air cooling of the condenser blower 13, and flows out of the condenser 12. The refrigerant goes out of the refrigerator unit 3 through the receiver tank 30, the filter dryer 44, and the moisture indicator 45, passes through the refrigerant pipe 7 through the electromagnetic valve 16, and is distributed to the showcases 5A and 5B. The distributed liquid refrigerant is decompressed by the expansion valves 17A and 17B of the showcases 5A and 5B, and then flows into the evaporators 15A and 15B to evaporate, thereby exhibiting a cooling action. The cool air cooled by the evaporators 15A and 15B is circulated into the storage compartments of the showcases by the cool air circulation fans 14A and 14B, whereby the products displayed in the storage compartments are cooled.

  The refrigerant that has flowed out of the evaporators 15A and 15B of the showcases 5A and 5B merges, returns to the refrigerator unit 3 through the refrigerant pipe 9, and repeats circulation that is sucked into the compressors 11 and 11. The refrigerant circuits in the refrigerant pipes 7 and 9, the refrigerator unit 3, and the showcases 5 </ b> A and 5 </ b> B have a plurality of welding points, screwing points, joints, and the like.

  Next, the receiver tank 30 will be described in detail with reference to FIG. 1 and FIG. FIG. 2 shows a schematic configuration diagram of the receiver tank 30. The receiver tank 30 has a vertically long shape, and is configured by a refrigerant storage part 32 that stores the refrigerant therein, and an inflow part 32A into which the refrigerant flowing out of the condenser 12 flows into the upper part of the refrigerant storage part 32. The filter dryer 44 is provided with an outflow portion 32B through which the refrigerant flows out. A plurality of sight glasses 35 are provided on the side surface of the refrigerant storage portion 32 so as to make the refrigerant liquid level stored inside visible from outside.

  In the present embodiment, the refrigerant reservoir 32 includes a plurality of float type refrigerant quantity sensors (receiver tank refrigerant quantity sensors; refrigerant quantity detection means) 36 and 37 for detecting the quantity of refrigerant stored therein. Is provided.

  The float type refrigerant amount sensors 36 and 37 have detection units 36A and 37A whose upper and lower portions communicate with the refrigerant storage unit 32 via communication pipes 36B and 37B. The detection units 36A and 37A The coolant level is substantially the same as the coolant level in the coolant reservoir 32. And in each detection part 36A, 37A, the some float 31 ... which comprises the refrigerant | coolant amount sensors 36, 37 and the some contact 33 ... which are opened and closed by each float 31 are provided. Each float 31 moves up and down together with the coolant level in the refrigerant reservoir 32 by allowing the refrigerant in the refrigerant reservoir 32 to flow into and out of the detectors 36A and 37A via the communication pipes 36B and 37B. It is provided above and below at a predetermined interval. In this embodiment, each of the refrigerant quantity sensors 36 and 37 is an eight-contact float sensor in which eight floats 31 and eight corresponding contacts 33 are provided.

  Thereby, the refrigerant | coolant liquid level in the receiver tank 30 (refrigerant storage part 32) can be detected exactly by detecting opening / closing of the contact 33 ... of each float type refrigerant | coolant amount sensors 36 and 37. FIG.

  The float type refrigerant quantity sensors 36 and 37 are arranged such that the positions of the respective contacts 33... Are shifted from each other in the vertical direction. In FIG. 2, one refrigerant amount sensor 36 is disposed on the other refrigerant amount sensor 37. In the present embodiment, the portions where the float type refrigerant amount sensors 36 and 37 overlap are provided such that the refrigerant liquid level is at the most general position (level, usually the center of the refrigerant reservoir 32). Further, in a state where the sensors 36 and 37 overlap with each other in a state of being shifted from each other, the distance between the contacts 33... Is approximately half (approximately ½) of the distance between only one contact 33. Set to

  Therefore, for example, when the interval between the contact points 33 of one refrigerant amount sensor is equivalent to 10% of the total amount, not only the refrigerant amount sensor 37 arranged to be shifted downward, but also shifted to the upper side. When all the contacts 33 of the refrigerant quantity sensor 36 are closed by the float 31 (ON), the refrigerant quantity (liquid refrigerant quantity) in the receiver tank 30 is detected as full (100%). When only the uppermost contact 33 of the upper refrigerant amount sensor 36 is OFF and all the other contacts 33 are ON, it is detected that the refrigerant amount in the receiver tank 30 is reduced by 10% from the whole.

  At this time, when only one refrigerant amount sensor is provided, when there is a coolant level between the uppermost contact 33 and the contact 33 immediately below the uppermost contact 33, the uppermost contact is provided. Only 33 is turned OFF, and the contact 33 below it is turned ON. However, in this case, the refrigerant level is reduced by 10% of the whole, or the refrigerant is reduced by 19%, for example, less than 20%. Whether it is a liquid level cannot be determined.

  However, in this embodiment, the refrigerant liquid level is provided at the most general position in such a manner that a plurality of (in this case, two) refrigerant quantity sensors 36 and 37 are provided so as to be displaced from each other in the vertical direction. When the upper part of the contact point 33 of the refrigerant amount sensor 37 shifted to the lower side is turned off and the upper side contact point 33 of the refrigerant quantity sensor 37 shifted to the lower side is turned on, the receiver tank 30 It can be determined that the refrigerant liquid level is between the uppermost contact 33 and the uppermost contact 33 of the refrigerant quantity sensor 37 at the overlapping part of the refrigerant quantity sensor 36.

  Therefore, in this case, in the overlapping part of the refrigerant amount sensor 36, the upper side contact 33 is turned off, the lower contact point 33 is turned on, and the uppermost contact point 33 of the refrigerant quantity sensor 37 is shifted downward. Is further turned OFF, it can be determined that there has been a decrease of less than 10% (for example, 9%) of the total at the overlapping portion, and the second contact 33 from the top at the overlapping portion of the refrigerant amount sensor 36. It becomes possible to determine that there has been a 10% reduction in the overlapped part only when the is turned OFF. Therefore, when a plurality of float type refrigerant quantity sensors are provided and the distance between the contact points 33 is the quantity of refrigerant equivalent to 10% of the whole, the accuracy can be 10%.

  As described above, the positions of the contacts 33... Of the respective float type refrigerant quantity sensors 36 and 37 are arranged so as to be shifted from each other in the vertical direction, so that the interval between the contacts 33. Thereby, the resolution can be increased. Therefore, the detection accuracy of the refrigerant liquid level can be improved.

  In this embodiment, two float type refrigerant quantity sensors are provided with the contacts 33 being vertically displaced from each other. However, the present invention is not limited to this, and a similar float type refrigerant quantity is provided. It is possible to increase the resolution of the refrigerant quantity detected by the refrigerant quantity sensors by providing three or more sensors and providing them with the contacts 33..

  In addition to this, the receiver tank refrigerant quantity sensor includes a plurality of receiver tank temperature sensors (receiver tank temperature detecting means) 50 (see FIG. 1) that detect the temperature of the refrigerant in the receiver tank 30 in the refrigerant reservoir 32 in the vertical direction. (In FIG. 1, five are shown, but the present invention is not limited to this. For example, eight to sixteen) may be provided.

  Since the temperature of the refrigerant in the receiver tank 30 differs between the liquid state and the gas state, when the temperature is lower than a predetermined value by detecting the temperature of each receiver tank temperature sensor 50, When there is a refrigerant and the temperature is equal to or higher than a predetermined temperature, it can be determined that there is no refrigerant at a position at the height, and the liquid level of the refrigerant can be accurately detected.

  Even in this case, as in the case where the receiver tank refrigerant quantity sensor is configured by the float type refrigerant quantity sensor, a plurality of receiver tank temperature sensors 50 provided in the upper and lower directions are arranged in such a manner that their positions are shifted from each other in the vertical direction. May be. Thereby, the space | interval of the receiver tank temperature sensor 50 of each group becomes small, and resolution | decomposability becomes high. Therefore, the detection accuracy of the refrigerant liquid level can be improved.

  When the receiver tank refrigerant quantity sensor is configured by the float type refrigerant quantity sensors 36 and 37 or the plurality of receiver tank temperature sensors 50, the receiver tank 30 has a vertically long shape as in the present embodiment. It becomes easy to cause the change of the refrigerant liquid level in the interior 30, and it is possible to realize a highly accurate refrigerant amount detection as will be described later.

  In addition to this, the receiver tank refrigerant amount sensor may be constituted by a measuring instrument that detects the weight of the receiver tank 30 itself. Thereby, the refrigerant | coolant amount stored in the receiver tank 30 can be detected appropriately with a measuring instrument.

  Next, in FIG. 3, 2 is a master controller installed in a store office or a maintenance company, 6 is a refrigerator controller provided in the refrigerator unit 3, and 8 is provided in each showcase 5A, 5B,. Showcase controller. Each of the controllers 2, 6 and 8 is composed of a general-purpose microcomputer, and is connected by a communication line 10 to transmit / receive data to / from each other, thereby constructing a control means for the refrigeration apparatus R. The unit 3 and the showcases 5A and 5B are centrally controlled.

  The compressor 11, 11, condenser blower 13, electromagnetic valve 16, etc. are connected to the output side of the refrigerator controller 6, and the discharge temperature sensor (discharge temperature detection means) 47 and the condenser inlet side are connected to the input side. Temperature sensor (condenser inlet side temperature detecting means) 48, condenser outlet side temperature sensor (condenser outlet side temperature detecting means) 49, receiver tank temperature sensor (receiver tank temperature detecting means) 50, and refrigerator unit outlet Side temperature sensor (refrigerator unit outlet side temperature detecting means) 51, evaporator inlet side temperature sensors (evaporator inlet side temperature detecting means) 52A, 52B, evaporator outlet side temperature sensor (evaporator outlet side temperature detecting means) ) 53A, 53B, suction temperature sensor (suction temperature detection means) 54, high pressure sensor (high pressure detection means) 46, low pressure sensor (low pressure detection means) 55, Batanku pressure sensor (receiver tank pressure detecting means) 56, each of float-type refrigerant quantity sensor (receiver tank refrigerant amount sensor) 36 and 37 are connected.

  The discharge temperature sensor 47 is provided in the refrigerant discharge pipe 24 connected to the discharge port 23 of the compressor 11 and detects the discharge refrigerant temperature discharged from the compressor 11. The high pressure sensor 46 is provided between the oil separator 26 and the condenser 12 and detects the discharge pressure of the refrigerant discharged from the compressor 11. The condenser inlet side temperature sensor 48 detects the refrigerant temperature flowing into the condenser 12, and the condenser outlet side temperature sensor 49 detects the refrigerant temperature flowing out of the condenser 12.

  The refrigerator unit outlet side temperature sensor 51 is provided between the receiver tank 30 and the filter dryer 44 and detects the temperature of the liquid refrigerant flowing out of the refrigerator unit 3. The evaporator inlet side temperature sensors 52A and 52B detect refrigerant temperatures flowing into the respective evaporators 15A and 15B, and the evaporator outlet side temperature sensors 53A and 53B flow out of the respective evaporators 15A and 15B. The refrigerant temperature detected is detected.

  The suction temperature sensor 54 is provided on the downstream side of the accumulator 27 and before the joining portion of the refrigerant introduction pipes 22 and 22 connected to each compressor 11, and detects the refrigerant temperature sucked into each compressor 11. The low pressure sensor 55 is provided between the strainer 28 and the accumulator 27 and detects the pressure on the low pressure side of the refrigerant circuit 1.

  The receiver tank pressure sensor 56 detects the pressure in the receiver tank 30, and the receiver tank temperature sensor 50 detects the temperature in the receiver tank 30. In addition, when the float type refrigerant quantity sensors 36 and 37 are provided as the receiver tank refrigerant quantity sensors, the receiver tank temperature sensor 50 may be single, and a plurality of receiver tank temperature sensors 50 are provided as the receiver tank refrigerant quantity sensors. In this case, it is not necessary to provide a float type refrigerant amount sensor. In this case, one of the receiver tank temperature sensors 50 constituting the receiver tank refrigerant amount sensor is used as the receiver tank temperature sensor 50 that detects the temperature in the receiver tank 30.

  On the other hand, the air circulation fans 14A and 14B and the expansion valves 17A and 17B are connected to the output side of the showcase controller 8 provided in each showcase 5A and 5B, and each showcase is connected to the input side. Internal temperature sensors 57A, 57B and the like for detecting the temperatures in the storage chambers 5A, 5B are connected.

  The master controller 2 includes a storage device (storage means) 61 including a readable / writable nonvolatile memory and a hard disk, an input device such as a keyboard and a mouse, and an output device such as a printer and a display (also a terminal 4). And an alarm device 60 including a buzzer and a lamp. In the storage device 61, software for control operations including defrost control is written and held in advance. Further, a display unit 62 with seven segments is provided on the substrate of the master controller 2.

  Hereinafter, the cooling operation of the refrigeration apparatus R will be described. The showcase controllers 8 of the showcases 5A and 5B open the expansion valves 17A and 17B at a predetermined upper limit temperature and open the expansion valves 17A and 17B at a lower limit temperature based on the outputs of the inside temperature sensors 57A and 57B. Closed. Moreover, the valve opening degree of expansion valve 17A, 17B is controlled based on the superheat degree of evaporator 15A, 15B. Thereby, the temperature in each storage chamber is maintained at a set temperature between the upper limit temperature and the lower limit temperature.

  Based on the output of the low-pressure sensor 55, the refrigerator controller 6 closes the expansion valves 17A and 17B of all the showcases 5A and 5B with the electromagnetic valve 16 open, and the low pressure drops to a predetermined lower limit value. The compressors 11 and 11 and the condenser blower 13 are stopped. Then, the compressors 11 and 11 and the condenser blower 13 are activated by the pressure increase on the low pressure side when the expansion valves 17A and 17B of any of the showcases 5A and 5B are opened with the electromagnetic valve 16 open.

  Data regarding operation control in each of the controllers 6 and 8 is collected by the master controller 2 via the communication line 10. Further, the master controller 2 also collects data related to failures in the showcases 5A and 5B and the refrigerator unit 3 from the controllers 6 and 8, respectively. In addition, the set temperature of each showcase 5A, 5B is transmitted from the master controller 2 to each showcase controller 8, and further data related to defrosting control is also transmitted. Accordingly, the master controller 2 can centrally control the showcases 5A and 5B and the refrigerator unit 3.

  Next, the refrigerant leakage detection operation in the refrigeration apparatus R will be described. First, in order to register (store) a reference value required for the refrigerant leakage detection operation in the storage device 61 of the master controller 2, the master controller 2 stores initial data when the refrigeration apparatus R is installed (at the start of operation). Perform the registration operation. Hereinafter, a description will be given with reference to the flowchart of FIG.

(1) Initial Data Registration Operation When the initial data registration operation starts in step S1, the master controller 2 proceeds to step S2 and requests input of the pipe diameter, pipe length, etc. of each part. In the present embodiment, in the refrigerant leakage detection operation, the refrigerant circuit 1 is divided into a plurality of regions, the refrigerant amount is calculated from the refrigerant density in each region and the volume of the region grasped in advance, and the initial data registration operation The refrigerant leakage is determined by comparing with the reference value registered in step.

  In the present embodiment, the refrigerant circuit 1 is divided into the first region, the region from the outlets of the evaporators 15A, 15B to the suction side of the compressors 11, 11, and the region from the compressors 11, 11 to the inlet of the condenser 12. The second region, the third region in the condenser 12, the region from the outlet of the condenser 12 to the inlet of the receiver tank 30, the fourth region, the fifth region in the receiver tank 30, and the outlet of the receiver tank 30 Is divided into a sixth region and the insides of the evaporators 15A and 15B are divided into seventh regions, and the refrigerant amount is calculated for each region (see FIG. 5).

  Therefore, in step S <b> 2, based on a request from the master controller 2, the administrator inputs the pipe diameter, pipe length, and the like of each part from the terminal 4 for each region. For the first region, the case-side refrigerant pipes 19A and 19B connected to the outlets of the evaporators 15A and 15B, the refrigerant pipe 9 connected thereto, the pipe diameter and the pipe of the refrigerant introduction pipe 22 leading to the compressors 11 and 11 Enter the length. Based on this, the master controller 2 calculates the volume of the area from the outlets of the evaporators 15A and 15B to the suction side of the compressors 11 and 11, and stores it in the storage device 61 as the volume of the first area.

  For the second region, the volume of the compressors 11 and 11 and the pipe diameter and pipe length of the refrigerant discharge pipe 25 from the compressor 11 to the inlet of the condenser 12 are input. Based on this, the master controller 2 calculates the volume of the area from the compressor 11 to the inlet of the condenser 12 and stores it in the storage device 61 as the volume of the second area. For the third region, the volume in the condenser 12 is input and stored in the storage device 61 as the volume of the third region.

  For the fourth region, the pipe diameter and the pipe length of the refrigerant pipe from the outlet of the condenser 12 to the inlet of the receiver tank 30 are inputted, and based on this, the master controller 2 enters the inlet of the receiver tank 30 from the outlet of the condenser 12. The volume of the area up to is calculated and stored in the storage device 61 as the volume of the fourth area.

  For the sixth area, the pipe diameter and pipe length of the refrigerant pipe 7 extending from the outlet of the receiver tank 30 to each of the evaporators 15A and 15B are input, and based on this, the master controller 2 sends each evaporator 15A from the outlet of the receiver tank 30. , 15B is calculated and stored in the storage device 61 as the volume of the sixth region. For the seventh area, the volume in each of the evaporators 15A and 15B is input and stored in the storage device 61 as the volume of the seventh area.

  At this time, the volumes of the condenser 12 and the evaporators 15A and 15B vary depending on the actually installed showcases 5A and 5B and the condenser unit (installed outdoors), and the detailed volume may not be grasped. Many. When the volume of these condensers and evaporators can be grasped, it can be stored in the storage device 61 as the volume of the third region and the volume of the seventh region. If input is omitted and only necessary areas are input (in the present embodiment, the first area, the second area, the fourth area, the fifth area, and the sixth area other than the volume of the third area and the seventh area). Good. In the following description, it is assumed that the volume of the third and seventh regions cannot be grasped (unknown). The volume of the fifth region is acquired by detecting the refrigerant liquid level in the receiver tank 30 as will be described later.

  Thereafter, the master controller 2 proceeds to step S3 and starts the refrigerant sealing operation. After the operator encloses the refrigerant in the refrigerant circuit 1 based on the instruction from the master controller 2, the master controller 2 requests the input of the type of refrigerant and the initial refrigerant amount. Based on this, the operator inputs the refrigerant type and the initial refrigerant amount from the terminal 4, and the master controller 2 stores the refrigerant type and the initial refrigerant quantity in the storage device 61.

  Thereafter, the master controller 2 proceeds to step S6 and starts a trial operation of the refrigeration apparatus R. In this test operation, the showcase controller 8 of each showcase 5A, 5B controls the expansion valves 17A, 17B based on the instruction from the master controller 2, and the refrigerator controller 6 The compressor 11 and the condenser blower 13 are controlled to cool the storage chamber to a set temperature between the upper limit temperature and the lower limit temperature (thermocycle operation).

  Then, the master controller 2 is based on the data collected from the showcase controller 8... And the refrigerator controller 6 and is in a stable state in which the temperature in the storage chamber is maintained between the upper limit temperature and the lower limit temperature in the thermocycle operation. It is confirmed whether or not (step S6). When it becomes a stable state, the master controller 2 acquires the refrigerant | coolant liquid level (volume) of the receiver tank 30 from the float type refrigerant | coolant amount sensors 36 and 37 via the refrigerator controller 6 (step S7).

  As described above, the refrigerator controller 6 detects the open / close state of each contact 33... Of each float type refrigerant amount sensor 36, 37, thereby adjusting the refrigerant liquid level in the receiver tank 30 (refrigerant storage unit 32). It can be accurately detected as a volume. Thereby, it is possible to grasp the amount of refrigerant in the receiver tank 30 based on the liquid level of the refrigerant.

  Thereafter, the master controller 2 proceeds to step S8, and calculates the refrigerant amount in each region. Specifically, the density of the refrigerant in the region is calculated from the temperature and pressure of each region, and the volume or float type refrigerant amount sensors 36 and 37 stored in the storage device 61 of the region as described above are calculated. By multiplying the refrigerant liquid level (volume) detected from the above, the amount of refrigerant in each region is calculated. The correlation equation for calculating the density from the pressure and temperature of the refrigerant sealed in the refrigerant circuit 1 is prepared in advance and registered in the storage device 61 of the master controller 2, and the correlation equation is used. Calculate the density.

  In the first region, the temperature is detected by the suction temperature sensor 54, and the value detected by the low pressure sensor 55 is used to calculate the density of the refrigerant in the first region. In the second region, the temperature is detected by the discharge temperature sensor 47, and the value detected by the high pressure sensor 46 is used to calculate the density of the refrigerant in the second region.

  In the third region, the average value of the inlet temperature of the condenser 12 detected by the condenser inlet side temperature sensor 48 and the outlet temperature of the condenser 12 detected by the condenser outlet side temperature sensor 49 was calculated. The value is used, and the value detected by the high pressure sensor 46 is used to calculate the density of the refrigerant in the third region. At this time, the refrigerant has a liquid / gas state change inside the condenser 12, but the temperature used for the calculation is an average value of the inlet and outlet temperatures of the condenser 12. It becomes possible to acquire the refrigerant density in the condenser 12 corresponding to.

  In the fourth region, the temperature is detected by the condenser outlet side temperature sensor 49, and the value detected by the high pressure sensor 46 is used to calculate the refrigerant density in the fourth region. In the fifth region, the temperature is detected by the receiver tank temperature sensor 50, and the value detected by the receiver tank pressure sensor 56 is used to calculate the refrigerant density in the fifth region.

  In the sixth region, the temperature is detected by the refrigerator unit outlet side temperature sensor 51, and the value detected by the receiver tank pressure sensor 56 is used to calculate the density of the refrigerant in the sixth region.

  The seventh region includes the inlet temperatures of the evaporators 15A and 15B detected by the evaporator inlet side temperature sensors 52A and 52B, and the evaporators 15A and 15B detected by the evaporator outlet side temperature sensors 53A and 53B. A value obtained by calculating an average value of the outlet temperature is employed, and a value detected by the low pressure sensor 55 is employed to calculate the density of the refrigerant in the seventh region. At this time, the refrigerant has a liquid / gas state change inside the evaporators 15A and 15B, but the temperature used for the calculation is an average value of the inlet and outlet temperatures of each of the evaporators 15A and 15B. It becomes possible to acquire the refrigerant density in the evaporators 15A and 15B corresponding to the seventh region.

  In the present embodiment, as described above, the volumes of the third and seventh regions cannot be grasped (unknown). Therefore, in step S8, the necessary areas other than the third and seventh areas, that is, the volumes of the first area, the second area, the fourth area, the fifth area, and the sixth area, The refrigerant amount in each region is calculated by multiplying the density of the refrigerant.

  At this time, the volume in the receiver tank 30 which is the fifth region was obtained by detecting the open / closed state of each contact 33... Of each float type refrigerant amount sensor 36, 37 as described in detail above. Since the refrigerant liquid level in the receiver tank 30 (refrigerant storage part 32) is adopted, and the amount of refrigerant in the region can be calculated based on this, the amount of refrigerant in the receiver tank can be obtained more accurately. Therefore, it is possible to realize highly accurate refrigerant leak detection.

  For the third and seventh regions, after calculating the respective refrigerant densities, the ratio of the refrigerant densities is calculated.

In step S9, the master controller 2 subtracts the sum of the refrigerant amounts in the first, second, fourth, fifth and sixth regions from the initial refrigerant filling amount stored in step S4, The refrigerant amounts in the third and seventh regions are calculated. Then, from the ratio between the refrigerant amount and the third and seventh refrigerant densities calculated above, the refrigerant amount in the third region (in the condenser 12) is calculated, and the refrigerant amount in the third region is normally set. It is stored (registered) in the storage device 61 as an operating leakage reference value (preliminary detection reference value).
Formula when the volume of the third and seventh regions is unknown:
Initial refrigerant filling amount− (first region refrigerant amount + second region refrigerant amount + fourth region refrigerant amount + fifth region refrigerant amount + sixth region refrigerant amount) = third Refrigerant amount in region + refrigerant amount in seventh region Normal operation leakage reference value = (refrigerant amount in third region + refrigerant amount in seventh region) x (refrigerant density in third region / (third region) Refrigerant density + refrigerant density in the seventh region))

  Next, the master controller 2 proceeds to step S10, and performs a pump-down operation and a simultaneous defrosting operation. At this time, since the master controller 2 transmits the defrosting start data to the refrigerator controller 6 and all the showcase controllers 8..., The refrigerator controller 6 stops the compressor 11 and the condenser blower 13 and the solenoid valve. 16 is left open, and the showcase controller 8 closes the expansion valves 17A and 17B. When a capillary tube is used as the throttle means instead of the expansion valve, the electromagnetic valve 16 is closed and the defrosting operation is performed.

  As a result, the refrigerant does not flow into the evaporators 15A and 15B, the temperature of the evaporators 15A and 15B rises, and the frost attached to the evaporators is melted and removed. The defrosting operation is terminated when the evaporators 15A and 15B reach a predetermined defrosting end temperature.

  When performing the defrosting operation, the refrigerator controller 6 operates the compressor 11 and the cooling air circulation fans 14A and 14B, and executes a pump-down operation for recovering the refrigerant in the evaporators 15A and 15B. . Note that the pump-down operation may be executed in several steps.

  Then, the master controller 2 proceeds to step S11 and acquires the refrigerant liquid level (volume) of the receiver tank 30 from the float type refrigerant quantity sensors 36 and 37 via the refrigerator controller 6.

  Thereafter, the master controller 2 proceeds to step S12, and similarly to step S8, detects the temperature and pressure of each region and calculates the density of the refrigerant inside the region from these, as described above. The amount of refrigerant in each region is calculated by multiplying the volume stored in the storage device 61 or the refrigerant liquid level (volume) detected from the float type refrigerant quantity sensors 36 and 37.

  In the present embodiment, since the volumes of the third and seventh regions are unknown, the volumes of the first region, the second region, the fourth region, the fifth region, and the sixth region and the refrigerant The refrigerant amount in each region is calculated by multiplying the density of each of the regions, and for the third and seventh regions, the respective refrigerant densities are calculated, and then the ratio of the refrigerant densities is calculated.

  In step S13, the master controller 2 subtracts the sum of the refrigerant amounts in the first, second, fourth, fifth, and sixth regions from the initial refrigerant charging amount stored in step S4. Thus, the refrigerant amounts in the third and seventh regions are calculated. Then, the refrigerant amount in the third region (in the condenser 12) is calculated from the ratio between the refrigerant amount and the third and seventh refrigerant densities calculated above, and the refrigerant amount in the third region is pumped. The down leak reference value (detail detection reference value) is stored (registered) in the storage device 61.

  Thereafter, the master controller 2 proceeds to step S14 to cancel the pump-down operation and the simultaneous defrosting operation, all the showcase controllers 8 open the expansion valve to a predetermined valve opening, and the refrigerator controller 6 The compressor 11 and the condenser blower 13 are activated to resume normal cooling operation (step S15). As described above, the master controller 2 ends the initial data registration operation.

(2) Refrigerant Leak Detection Operation Next, the refrigerant leak detection operation in the present embodiment will be described with reference to the flowchart of FIG. The master controller 2 starts a normal cooling operation (step S21), and performs preliminary detection of refrigerant leakage at a predetermined cycle.

(2-1) Preliminary detection operation The master controller 2 performs a step after a predetermined period has elapsed since the start of normal cooling operation, or after a predetermined period has elapsed since the completion of the previous preliminary detection operation or detailed detection operation. Proceeding to S22, a preliminary detection operation is executed. First, the master controller 2 is based on the data collected from the showcase controller 8... And the refrigerator controller 6 and is in a stable state in which the temperature in the storage chamber is maintained between the upper limit temperature and the lower limit temperature in the thermocycle operation. When the master controller 2 is in a stable state, the master controller 2 acquires the refrigerant liquid level (volume) of the receiver tank 30 from the float type refrigerant quantity sensors 36 and 37 via the refrigerator controller 6. (Step S22).

  Thereafter, the master controller 2 proceeds to step S23, and calculates the refrigerant amount in each region in the same manner as in step S8 as described above. In the present embodiment, as described above, the volumes of the third and seventh regions cannot be grasped, and therefore the first region, the second region, the fourth region, the fifth region, and the sixth region. The density of the refrigerant inside the area is calculated from the temperature and pressure, and the volume stored in the storage device 61 of the area as described above or the refrigerant liquid level detected from the float type refrigerant amount sensors 36 and 37 is calculated. By multiplying (volume), the amount of refrigerant in each region is calculated. For the third and seventh regions, the refrigerant density inside the region is calculated from the temperature and pressure of each region, and then the ratio of the refrigerant densities is calculated. The calculation method is the same as in step S8.

  Thereafter, the master controller 2 proceeds to step S24, and the first, second, fourth, fifth and sixth regions calculated in step S23 are calculated from the initial refrigerant filling amount stored in the initial data registration operation. The refrigerant amount in the third and seventh regions is calculated by subtracting the sum of the refrigerant amounts. Then, the amount of refrigerant in the third region (in the condenser 12) is calculated from the ratio between the amount of refrigerant and the third and seventh refrigerant densities calculated above, and the amount of refrigerant in the third region is the initial value. It is determined whether or not the normal operation leakage reference value stored in the data registration operation is within an allowable range. Note that the moving average is always used as the amount of refrigerant in the third region used for the determination.

  That is, if the amount of refrigerant in the third region calculated in step S24 is larger than the predetermined allowable range from the normal operation leakage reference value, it can be determined that the amount in the other region is reduced. Thus, it can be determined that the refrigerant leaks.

  Since the normal operation leakage reference value is stored in the recording device 61 in the initial data registration operation, the refrigerant amount in the third region calculated in the preliminary detection operation and the initial data registration operation at the start of operation are stored. By comparing the calculated amount of refrigerant in the third region (normal operation leakage reference value), refrigerant leakage from the refrigerant circuit can be detected quickly and easily.

  If it is not determined in step S24 that the refrigerant leaks, that is, if the calculated amount of refrigerant in the third region is within the allowable range compared to the normal operation leakage reference value, the process proceeds to step S25. The master controller 2 determines whether or not the current setting is the periodic leak detection ON (in the regular leak detection mode). This periodic leak detection is performed periodically (at least at a period longer than the period of the preliminary detection operation) regardless of whether or not the refrigerant leakage determination is made in the preliminary detection operation in various settings at the start of operation. Is set to execute or not. If the regular leak detection is set to ON (in the regular leak detection mode), the process proceeds to step S29 described later, and if it is set to OFF, the process proceeds to step S26.

  When it progresses to step S26, the master controller 2 judges whether it is a fixed-time defrost operation, and when it is not a fixed-time defrost operation, it returns to step S22, and when it is a fixed-time defrost timing, it progresses to step S27. Then, defrosting start data is transmitted from the master controller 2 to the refrigerator controller 6 and all the showcase controllers 8.

  As a result, the refrigerator controller 6 stops the compressor 11 and the condenser blower 13 while keeping the electromagnetic valve 16 open, and the showcase controller 8 closes the expansion valves 17A and 17B. When a capillary tube is used as the throttle means instead of the expansion valve, the electromagnetic valve 16 is closed and the defrosting operation is performed. As a result, the refrigerant does not flow into the evaporators 15A and 15B, the temperature of the evaporators 15A and 15B rises, and the frost attached to the evaporators is melted and removed. The defrosting operation is terminated when the evaporators 15A and 15B reach a predetermined defrosting end temperature. After completion of the defrosting operation, the master controller 2 returns to step S21 and starts a normal cooling operation.

  On the other hand, if it is determined that the refrigerant leaks in the preliminary detection operation in step S24, that is, if the calculated refrigerant amount in the third region is not within the allowable range compared to the normal operation leak reference value, the refrigerant leak If it is suspected, the process proceeds to step S28, and an internal alarm is issued to the display unit 62 of the seven segments of the master controller 2 substrate.

  In the preliminary detection operation as described above, since the volumes of the third region (in the condenser 12) and the seventh region (in the evaporators 15A and 15B) are unknown, the amount of refrigerant in these regions is unclear. is there. In particular, in the evaporators 15A and 15B, it is easy for the refrigerant to stagnate, and the error greatly affects it, so that the amount of refrigerant that has stagnation incorrectly is not calculated, and accordingly, the refrigerant may be regarded as having leaked. Therefore, when it is determined that the refrigerant has leaked in the preliminary detection operation, the detailed detection operation is executed.

(2-2) Detailed Detection Operation The master controller 2 proceeds to step S29, and executes a pump down operation and a simultaneous defrosting operation. At this time, since the master controller 2 transmits the defrosting start data to the refrigerator controller 6 and all the showcase controllers 8..., The refrigerator controller 6 stops the compressor 11 and the condenser blower 13 and the solenoid valve. 16 is left open, and the showcase controller 8 closes the expansion valves 17A and 17B. When a capillary tube is used as the throttle means instead of the expansion valve, the electromagnetic valve 16 is closed and the defrosting operation is performed.

  When performing the defrosting operation, the refrigerator controller 6 operates the compressor 11 and the cooling air circulation fans 14A and 14B, and executes a pump-down operation for recovering the refrigerant in the evaporators 15A and 15B. . Note that the pump-down operation may be executed in several steps.

  Then, the master controller 2 proceeds to step S30, and acquires the refrigerant liquid level (volume) of the receiver tank 30 from the float type refrigerant quantity sensors 36 and 37 via the refrigerator controller 6.

  Thereafter, the master controller 2 proceeds to step S31, and calculates the refrigerant amount in each region in the same manner as in step S23. In the present embodiment, as described above, the volumes of the third and seventh regions cannot be grasped, so that the regions necessary for refrigerant leakage detection, that is, the first region, the second region, the fourth region, The density of the refrigerant in the area is calculated from the temperature and pressure of the area and the sixth area, and the volume stored in the storage device 61 of the area as described above or the float type refrigerant amount sensor 36 is calculated. , 37 is multiplied by the refrigerant liquid level (volume) to calculate the amount of refrigerant in each region. For the third and seventh regions, the refrigerant density inside the region is calculated from the temperature and pressure of each region, and then the ratio of the refrigerant densities is calculated. The calculation method is the same as in step S23.

  Thereafter, the master controller 2 proceeds to step S32, and the first, second, fourth, fifth, and sixth areas calculated in step S31 are calculated from the initial refrigerant filling amount stored in the initial data registration operation. The refrigerant amount in the third and seventh regions is calculated by subtracting the sum of the refrigerant amounts. Then, the amount of refrigerant in the third region (in the condenser 12) is calculated from the ratio between the amount of refrigerant and the third and seventh refrigerant densities calculated above, and the amount of refrigerant in the third region is the initial value. The pump-down leakage reference value stored in the data registration operation is compared (step S32), and it is determined whether or not the calculated refrigerant amount in the third region is within an allowable range with respect to the pump-down leakage reference value. (Step S33).

  That is, if the amount of refrigerant in the third region calculated in step S31 is larger than the predetermined allowable range from the pump-down leakage reference value, it can be determined that the amount in the other region is reduced. Thus, it can be determined that the refrigerant leaks.

  Therefore, the amount of refrigerant in the third region calculated in the detailed detection operation and the amount of refrigerant in the third region (pump down calculated in the initial data registration operation at the start of operation with the pump-down operation). The leakage of refrigerant from the refrigerant circuit can be detected quickly and easily.

  In particular, in the detailed detection operation, by performing a pump-down operation for collecting the refrigerant that has fallen in the evaporators 15A and 15B in the receiver tank 30, the refrigerant that has fallen in the evaporator and the like is collected, and there is little. As a state, the refrigerant leakage determination can be performed, and the stagnant refrigerant in the unclear region can be minimized, and the error can be further reduced.

  Therefore, it is determined whether or not refrigerant leakage is suspected by the preliminary detection operation that is periodically performed in the normal operation state, and only when it is determined that the refrigerant is leaking, by performing the detailed detection operation with the pump down operation, The amount of refrigerant in the third region (in the condenser 12) can be specified with high accuracy while minimizing the influence on the normal cooling operation. Therefore, the accuracy of refrigerant leakage detection can be further increased.

  If it is not determined in step S33 that the refrigerant leaks, that is, if the calculated amount of refrigerant in the third region is within the allowable range compared to the pump-down leak reference value, the process proceeds to step S35. If it is determined in step S33 that the refrigerant leaks, that is, if the calculated amount of refrigerant in the third region is not within the allowable range compared to the pump-down leak reference value, the process proceeds to step S34. In step S34, an alarm operation by the alarm device (buzzer or lamp) 60 is executed based on the output from the master controller 2, and then the process proceeds to step S35. As a result, it is possible to notify the user of the occurrence of refrigerant leakage at an early stage to minimize the amount of leakage, and to suppress deterioration of articles in the storage chamber and adverse effects on the environment to a minimum. .

  In step S35, defrosting completion (release) data is transmitted from the master controller 2 to the refrigerator controller 6 and all the showcase controllers 8. And it progresses to step S36 and returns to step S21, and a normal cooling operation is started.

  As described in detail above, in the present embodiment, in both the preliminary detection operation and the detailed detection operation, the refrigerant circuit is divided into a plurality of regions, and the temperature and pressure in the regions necessary for detecting the refrigerant leakage are used. The refrigerant density in the region is calculated, the refrigerant amount is calculated by multiplying the refrigerant density by the volume of the region, and the refrigerant leakage from the refrigerant circuit is determined based on the calculated refrigerant amount. For this reason, it is possible to divide each region where the state of the refrigerant is different and calculate the amount of the refrigerant by dividing the region where the state of the refrigerant is known and the region where it is difficult to grasp the state of the refrigerant.

  Therefore, as described above, in the condenser 12 corresponding to the third region and the evaporators 15A and 15B corresponding to the seventh region, it is difficult to grasp the state of the internal refrigerant and the capacity of itself, The amount of refrigerant in the first region, the second region, the fourth region, the fifth region, and the sixth region in which the other capacities can be grasped (required regions) is calculated, and these are calculated. The refrigerant amount in the third region and the seventh region is calculated by subtracting from the initial refrigerant charging amount, the refrigerant density in the third region and the seventh region is calculated, and the ratio of the calculated refrigerant densities is calculated. By comparing the amount of refrigerant in the third region obtained from the above and the reference value related to the amount of refrigerant in the third region to determine refrigerant leakage, the region where the state of the refrigerant is unknown is determined to be only the third region. Identify the normal operation leak reference value for the preliminary detection operation and pump down for the detailed detection operation. By comparing the model reference value, it is possible to further improve the accuracy of refrigerant leakage detection.

  In this embodiment, in the initial data registration operation, the refrigerant amount in the third region is calculated from the ratio of the refrigerant density in the third and seventh regions where the volume is unknown, and the normal operation leakage reference value or pump down is calculated. The refrigerant leakage determination is performed in the preliminary detection operation or the detailed detection operation using the operation leakage reference value, but is not limited to this. The refrigerant amounts in the third and seventh regions obtained by subtracting the refrigerant amount in each region (first, second, fourth, fifth, and sixth regions) that can be grasped may be employed.

  As a result, the current values of the third and seventh regions are grasped by the value obtained by subtracting the refrigerant amount of the first, second, fourth, fifth, and sixth regions from the initial refrigerant charging amount, And these reference values are compared, it is possible to quickly and easily detect refrigerant leakage in the refrigerant circuit.

In addition, when the volume of all the areas can be grasped, the refrigerant amount in each area is calculated by multiplying the density of the refrigerant in each area corresponding to the volume in each area. Then, a value obtained by subtracting the sum of the refrigerant amounts in each region from the initial refrigerant charging amount may be adopted as the normal operation leakage reference value or the pump-down operation leakage reference value.
Formula when the volume of the whole area can be grasped:
Normal operation leakage reference value = initial refrigerant charge amount− (first region refrigerant amount + second region refrigerant amount + third region refrigerant amount + fourth region refrigerant amount + fifth region refrigerant) Amount + refrigerant amount in the sixth region + refrigerant amount in the seventh region)

  In this case, refrigerant leakage in the refrigerant circuit can be detected with higher accuracy and speed.

  In this embodiment, when performing the detailed detection operation, the pump-down operation is executed, and the operation of sucking the refrigerant in the evaporators 15A and 15B is executed. Accordingly, in step S29, the evaporation is performed. A defrosting operation for thawing and removing the frost attached to the containers 15A and 15B is executed. Therefore, when the refrigerant in the evaporators 15A and 15B is sucked in the pump-down operation and the temperature of the evaporators 15A and 15B rises, the efficiency is improved by performing defrosting that similarly increases the temperature of the evaporator. Defrost and refrigerant leakage can be determined.

  Furthermore, in this embodiment, the master controller 2 determines whether or not the setting for periodic leak detection is ON in step S25, and if the setting for periodic leak detection is ON, preliminary detection is performed. Regardless of whether or not the refrigerant leakage is determined in the operation, that is, even when the refrigerant leakage is not determined, the detailed detection operation is periodically performed. Therefore, it is possible to periodically perform the detailed detection operation, and it is possible to realize highly accurate refrigerant leak detection.

  In particular, when HFC is adopted as the refrigerant as in the present embodiment, a receiver tank 30 is provided in the refrigerant circuit and a relatively large amount of refrigerant is enclosed, and it is difficult to detect refrigerant leakage. As described above, according to the present invention, it is possible to compare the reference value in the initial data registration operation with the refrigerant amount calculated in each detection operation with high accuracy, and quickly and accurately find the refrigerant leakage. It becomes possible.

R Refrigeration equipment C Control equipment (control means)
1 Refrigerant circuit 2 Master controller (control means)
DESCRIPTION OF SYMBOLS 3 Refrigerator unit 4 Terminal 5A, 5B Showcase unit 6 Refrigerator controller 7, 9 Refrigerant piping 8 Showcase controller 10 Communication line 11 Compressor 12 Condenser 13 Condenser blower 14A, 14B Cold air circulation blower 15A, 15B Evaporator 16 Solenoid valve 17A, 17B Expansion valve (throttle means)
Reference Signs List 30 Receiver tank 31 Float 32 Refrigerant reservoir 33 Contact 36, 37 Float type refrigerant quantity sensor (receiver tank refrigerant quantity sensor; refrigerant quantity detection means)
46 High pressure sensor (High pressure detector)
47 Discharge temperature sensor (Discharge temperature detection means)
48 Condenser inlet side temperature sensor (Condenser inlet side temperature detection means)
49 Condenser outlet side temperature sensor (Condenser outlet side temperature detection means)
50 Receiver tank temperature sensor (receiver tank temperature detection means)
51 Refrigerator unit outlet side temperature sensor (refrigerator unit outlet side temperature detection means)
52A, 52B Evaporator inlet side temperature sensor (Evaporator inlet side temperature detection means)
53A, 53B Evaporator outlet side temperature sensor (Evaporator outlet side temperature detection means)
54 Suction temperature sensor (suction temperature detection means)
55 Low pressure sensor (low pressure detector)
56 Receiver tank pressure sensor (receiver tank pressure detection means)
57A, 57B Internal temperature sensor 60 Alarm device 61 Storage device (storage means)
62 Display (7 segments)

Claims (11)

In the refrigeration apparatus in which the refrigerant circuit is configured by the compressor, the condenser, the receiver tank, the throttle means, and the evaporator,
Comprising control means for detecting refrigerant leakage from the refrigerant circuit;
The control means divides the refrigerant circuit into a plurality of regions in a normal operation state, calculates the refrigerant density in the region from the temperature and pressure of the region necessary for detection of refrigerant leakage, and calculates the refrigerant density in the region. A refrigerant amount is calculated by multiplying the volume, and a preliminary detection operation for determining refrigerant leakage from the refrigerant circuit based on the calculated refrigerant amount is periodically executed,
When it is determined that the refrigerant leaks in the preliminary detection operation, a pump-down operation is performed to collect the refrigerant in the receiver tank, the refrigerant circuit is divided into a plurality of areas, and the temperature of the area necessary for detecting the refrigerant leak The refrigerant density in the region is calculated from the pressure and the pressure, the refrigerant amount is calculated by multiplying the refrigerant density by the volume of the region, and the refrigerant leakage from the refrigerant circuit is determined based on the calculated refrigerant amount. A refrigeration apparatus that performs a detailed detection operation.   2. The refrigeration apparatus according to claim 1, wherein the control unit has a mode in which the detailed detection operation is periodically executed regardless of whether or not refrigerant leakage is determined in the preliminary detection operation.   The refrigerating apparatus according to claim 1 or 2, wherein the control means performs defrosting of the evaporator when performing the detailed detection operation.   The control means includes a first region in the region from the outlet of the evaporator to the suction side of the compressor, a second region in the region from the compressor to the inlet of the condenser, and a second region in the condenser. The third region, the region from the condenser outlet to the receiver tank inlet is the fourth region, the receiver tank is the fifth region, and the region from the receiver tank outlet to the evaporator inlet is the second region. The refrigeration apparatus according to any one of claims 1 to 3, wherein the refrigerant circuit is divided into a sixth region and the inside of the evaporator as a seventh region.   The control means calculates the refrigerant amount in the first region, the second region, the fourth region, the fifth region, and the sixth region, and subtracts these from the initial refrigerant charging amount and The refrigerant leakage is determined by comparing a reference value related to the refrigerant amount in the third area and the seventh area.   The control means calculates the refrigerant amounts of the first region, the second region, the fourth region, the fifth region, and the sixth region, subtracts these from the initial refrigerant charging amount, and The third region obtained from the ratio of each refrigerant density calculated by calculating the refrigerant amount of the third region and the seventh region, calculating the refrigerant density of the third region and the seventh region. The refrigerant leakage is determined by comparing the amount of refrigerant and a reference value related to the amount of refrigerant in the third region.   The control means uses an average value of the inlet and outlet temperatures of the condenser as a temperature for calculating the refrigerant density in the third region, and uses it as a temperature for calculating the refrigerant density in the seventh region. The refrigeration apparatus according to claim 6, wherein an average value of the inlet and outlet temperatures of the evaporator is used. A receiver tank refrigerant amount detection means for detecting a liquid level in the receiver tank is provided, and the control means uses the liquid level in the receiver tank as the volume of the fifth region, and the volume, temperature, and 8. The refrigeration apparatus according to claim 4 , wherein the refrigerant amount in the receiver tank is calculated based on the pressure. The control means includes means for recording the initial refrigerant filling amount and the volumes of at least the first area, the second area, the fourth area, the fifth area, and the sixth area. The refrigeration apparatus according to any one of claims 4 to 8, wherein the refrigeration apparatus is provided.   The said control means is provided with the means to memorize | store the said reference value of the temperature and pressure of each said area | region at the time of a driving | operation start, or each of these, said preliminary | backup detection operation | movement, and detailed detection operation | movement. The refrigeration apparatus according to any one of claims 9 to 9. The refrigeration apparatus according to any one of claims 1 to 10, wherein the control unit issues a predetermined alarm when it is determined that the refrigerant leaks in the detailed detection operation.

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