JP5410114B2 - Refrigeration equipment - Google Patents

Description

  In the present invention, the refrigerant compressed by the compressor condenses in the condenser, passes through a receiver tank (also referred to as a liquid receiver), passes through a decompression unit, evaporates in the evaporator, and recirculates the refrigerant back to the compressor. More particularly, the present invention relates to a technique for detecting a refrigerant leak in a refrigeration apparatus.

  A plurality of refrigeration / refrigeration showcases each equipped with an evaporator are provided, and the refrigerant compressed by the plurality of compressors is condensed by the plurality of condensers, passes through the decompression section and is evaporated by the evaporator, and then the compressor again. For example, Patent Document 1 discloses a system in which a refrigerant discharged from a condenser flows into an evaporator through a receiver tank (also referred to as a liquid receiver) in a refrigeration apparatus that circulates a refrigerant returning to the refrigerant.

  Further, in an air conditioning apparatus that performs heat exchange between the heat source side refrigerant cycle and the use side refrigerant cycle and performs air conditioning with the use side refrigerant cycle, the use side refrigerant cycle is provided with a refrigerant amount adjustment tank, The refrigerant level is detected by one or two liquid level position sensors, and the refrigerant level in the refrigerant quantity adjustment tank is detected by the liquid level position sensor during operation of the air conditioning system. For example, Patent Literature 2 discloses a technique for displaying a warning and continuing the operation of the air conditioning apparatus.

Japanese Patent Laid-Open No. 11-83280 JP 2000-74469 A

  In order for the refrigeration apparatus of Patent Document 1 to operate normally, it is necessary that the amount of refrigerant charged in the refrigeration apparatus is maintained in an appropriate range. For this reason, a technique for checking whether or not the refrigerant amount is maintained in an appropriate range is required. On the other hand, in the technique of Patent Document 2 that detects a refrigerant quantity shortage state, the refrigerant level in the refrigerant quantity adjustment tank provided in the use side refrigerant cycle is determined depending on whether the liquid level position sensor is submerged or in the air. This is to detect whether there is a shortage.

  Since the thing of patent document 2 is an electrode type, it becomes a liquid level detection in the condition which touches a refrigerant | coolant, and is eroded by a refrigerant | coolant and becomes a thing with poor durability. Further, during operation of the air conditioning system, the refrigerant level in the refrigerant quantity adjustment tank is a technology that detects whether the refrigerant quantity is insufficient by whether the liquid level position sensor is submerged or in the air. If the liquid surface position sensor is in the air detection state due to the fluctuation of the refrigerant liquid level during the ON-OFF operation of the engine (liquid wave undulation), the refrigerant amount shortage is detected. In order to prevent such erroneous detection, the operation is performed so that stable detection can be performed by the control circuit so that a refrigerant shortage state is not detected by such temporary fluctuation of the water level, but a substantial refrigerant shortage state can be detected. Although it is necessary to determine the level, an error occurs in the detection of the substantial refrigerant shortage state depending on how the operation level is set. For this reason, there is a problem that it is necessary to increase the initial refrigerant charging amount excessively, and so-called wasteful refrigerant charging amount is required.

  The present invention does not detect the refrigerant liquid level during normal operation of the refrigeration apparatus as in Patent Document 2, but detects whether or not the refrigerant is in a deficient state to a place to be cooled such as a refrigeration / refrigeration showcase. In a predetermined situation where the influence of Further, the present invention provides a technique that is excellent in the durability of the detection portion and can stably detect a substantial refrigerant leakage state.

The refrigeration apparatus of the present invention has a configuration in which a plurality of showcases each provided with an evaporator provided with an electric expansion valve in an inlet pipe are installed indoors, and the refrigerant compressed by the compressor is condensed by the condenser and flows into the receiver tank A condensing unit is installed outdoors, and the refrigerant in the receiver tank is piped so that the refrigerant flows through the single refrigerant pipe communicating with the receiver tank and each electric expansion valve to each electric expansion valve. In
The refrigerant pipe is opened in the cooling operation of the showcase in the downstream part of the refrigerant pipe before the refrigerant pipe is diverted to the electric expansion valves to function as a part of the receiver tank during the refrigerant recovery operation. In operation, there is a single solenoid valve that closes,
In the receiver tank, a plurality of the reed switches are arranged so that the reed switches from the lower order to the higher order are operated by a float with a magnet that rises as the stored refrigerant liquid level rises,
Based on the temperature detection of a temperature sensor that detects the temperature of the cooled part of each showcase, the corresponding electric expansion valve appropriately controls the decompression state of the refrigerant, and the solenoid valve is closed to operate the compressor. An operation for performing a refrigerant recovery operation for recovering the refrigerant to the refrigerant pipe and the receiver tank, and a measured value and a storage unit in which the reed switch is operated in response to a rising liquid level of the receiver tank after the refrigerant recovery operation. A control unit for performing an operation of determining the amount of refrigerant by comparison with a stored liquid level specified value;
The operation of the compressor in the refrigerant recovery operation can be performed for a certain period of time, or even if the reed switch at a position corresponding to the rising liquid level of the receiver tank is operated and a predetermined time has elapsed, It is operation until it does not work,
A display unit configured to display a determination result of the control unit, wherein the display unit is an LED that lights up when the liquid level of the receiver tank is equal to or higher than the specified value; an LED that lights up at a minimum level of refrigerant shortage; It is characterized by comprising an LED that is lighter than a specified value and higher than the minimum level .

  In the present invention, since the refrigerant leak state is detected after the refrigerant recovery operation, it is possible to prevent erroneous detection due to changes in the refrigerant liquid level during normal operation, and stable detection can be achieved. In addition, since the refrigerant leakage state can be detected after the refrigerant recovery operation performed in a predetermined situation (for example, at night) instead of the time zone in which the normal operation of the refrigeration apparatus is required, If the product to which the refrigeration system is applied is a freezer / refrigerated showcase, etc., it can be performed in a situation where there is little influence on the place to be cooled such as the freezer / refrigerated showcase, etc. .

  Further, the refrigerant pipe connecting the condensing unit and the showcase can be used as a part of the receiver tank, so that the receiver tank can be miniaturized and the refrigerant leakage can be detected under the same stable conditions.

It is a block diagram of the system which applied the freezing apparatus which concerns on this invention to a large sized showcase. It is the typical refrigerant circuit diagram which applied the refrigerating device concerning the present invention to a large-sized showcase. FIG. 2 is a refrigerant circuit diagram of the first embodiment of the refrigeration apparatus corresponding to FIG. 1. It is a refrigerant circuit diagram of 2nd Embodiment of the freezing apparatus corresponding to FIG. It is explanatory drawing of the control part of the freezing apparatus which concerns on this invention. It is explanatory drawing of the liquid level detection part of the freezing apparatus which concerns on this invention. It is sectional drawing of the AA part in FIG. 6 of the liquid level detection part which concerns on this invention. It is a related figure of the liquid level and the refrigerant | coolant filling amount of the freezing apparatus which concerns on this invention. It is explanatory drawing of the operation level of the liquid level detection part which detects the refrigerant | coolant liquid level of the freezing apparatus which concerns on this invention.

  In the present invention, the refrigerant compressed by the compressor condenses in the condenser, passes through a receiver tank (also referred to as a liquid receiver), passes through a decompression unit, evaporates in the evaporator, and recirculates the refrigerant back to the compressor. In the apparatus, the receiver tank includes a vertically long refrigerant storage unit and a liquid level detection unit that detects the stored refrigerant liquid level, and the liquid level detection unit includes a magnet that moves up and down according to a change in the refrigerant liquid level. A control including a float and a reed switch operated by the float with magnet, and performing a predetermined display based on the detection of the liquid level detection unit after the refrigerant recovery operation for recovering the refrigerant of the refrigeration apparatus to the liquid receiver It has a part.

  Hereinafter, an embodiment in which the refrigeration apparatus according to the present invention is applied to a large showcase installed in a supermarket or the like will be described with reference to the drawings. As shown in FIG. 1, this type of large-scale showcase SC is installed in a store such as a supermarket and is controlled to a predetermined temperature by the refrigeration apparatus RU according to the present invention. Condensing unit CU installed in For this reason, as will be described later, each showcase SC incorporates an evaporator 5 connected to the condensing unit CU via a refrigerant pipe RP.

  In the refrigeration apparatus RU according to the present invention, as shown in FIG. 2, the refrigerant compressed by the compressor 1 condenses in the condenser 2 and evaporates through the receiver tank (also referred to as liquid receiver) 3 through the decompression unit 4. The refrigerant is circulated by evaporating in the vessel 5 and returning to the compressor 1 again. Reference numeral 6 denotes an on-off valve that operates when a refrigerant recovery operation described later is performed.

  The condensing unit CU mainly includes a plurality of compressors (also referred to as compressors) 1, a condenser (also referred to as a condenser) 2 in which refrigerant compressed by the compressor 1 is condensed, and refrigerant discharged from the condenser 2. A receiver tank (also referred to as a liquid receiver) 3 is stored. The refrigerant exiting the receiver tank 3 flows through the refrigerant pipe RP, and then is divided. After being depressurized by each decompression unit 4 constituted by an electric expansion valve, the refrigerant flows to the evaporator 5 of each showcase SC. Each showcase SC is cooled by evaporating. The refrigerant gas exiting the evaporator 5 returns to the compressor 1 again, is compressed by the compressor 1, and repeats the above circulation.

  In the management room AD provided in a store such as a supermarket or in another remote building, remote control and setting of the operating conditions of the refrigeration unit RU, the operating status of each showcase SC, etc. A remote control device 20 for performing remote monitoring is provided. The remote control device 20 and the refrigeration unit RU may be connected to the control unit 16 of the refrigeration unit RU via a dedicated line or may be connected via an Internet line so as to perform information communication by wire or wirelessly.

  The receiver tank 3, which is one of the features of the present invention, includes a vertically long refrigerant reservoir 3 </ b> A and a liquid level detector 7 that detects the stored refrigerant liquid level RL. The refrigerant storage part 3A has a vertically long cylindrical shape, and the inlet pipe 8A and the stored refrigerant liquid flow out from the lower part of the refrigerant storage part 3A so that the refrigerant exiting the condenser 2 flows from the upper part of the refrigerant storage part 3A. Is provided with an outlet pipe 8B.

  The liquid level detection unit 7 includes detection pipes 9 communicated with the upper and lower portions of the refrigerant storage unit 3A through communication pipes 9B so as to be at the same level as the refrigerant liquid level of the refrigerant storage unit 3A. A float 10 with a magnet 11 is accommodated in the detection pipe 9 so as to move up and down by the liquid level of the detection pipe 9 which fluctuates according to the fluctuation of the refrigerant liquid level, and the detection pipe 9 has a float so as not to contact the refrigerant. A plurality of reed switches 12 are vertically arranged so that the magnets corresponding to the positions corresponding to the magnets 11 are operated by 10 vertical movements. As described above, the liquid level detection unit 7 moves the float 10 with the magnet 11 up and down by the liquid level of the detection pipe 9 that fluctuates according to the fluctuation of the refrigerant liquid level in the refrigerant storage unit 3 </ b> A. 12 is a system that operates.

  One configuration of the liquid level detection unit 7 having such a function is shown in FIGS. The configuration shown in FIGS. 6 and 7 is such that the detection pipe 9 communicated with the upper and lower portions of the refrigerant storage portion 3A through the communication pipe 9B with respect to the vertically long cylindrical refrigerant storage portion 3A installed substantially vertically. The storage unit 3A is provided substantially vertically outside. The detection pipe 9 is made of metal such as stainless steel so as to be pressure resistant. Inside the detection pipe 9, a metal inner pipe 9 </ b> A such as stainless steel is disposed concentrically with the detection pipe 9. The detection pipe 9 is coupled to the inner pipe 9A at a lower end portion in a watertight state. As a result, a refrigerant liquid level that is the same level as the refrigerant liquid level RL of the refrigerant reservoir 3A is formed in the cylindrical refrigerant reservoir space 9C formed between the inner pipe 9A and the detection pipe 9.

  In the inner pipe 9A, a plurality of reed switches 12 are accommodated and arranged at substantially equal intervals in the vertical direction so as not to contact the refrigerant. Outside the inner pipe 9A, a float 10 with a magnet 11 is accommodated in the refrigerant storage space 9C so as to move up and down using the inner pipe 9A as a support column in accordance with the change in the coolant level in the detection pipe 9. . Accordingly, the reed switch 12 at the position corresponding to the magnet 11 is operated by the vertical movement of the float 10.

  The distance between the reed switches 12 is sufficiently smaller than the thickness dimension of the magnets 11 in the vertical direction, and even when the magnets 11 are in the middle position between the reed switches 12 adjacent to each other, both the adjacent reed switches 12 are at the same time. It doesn't work. For this reason, the reed switch 12 actuated by the magnet 11 as the float 10 moves up and down is one, so that the coolant level in the coolant reservoir 3A can be accurately detected. Each reed switch 12 is electrically connected to the control unit 16 via a lead wire 13 led out from the lower end of the inner pipe 9A and a terminal 14 to which the lead wire 13 is connected. Note that a circular see-through window 15 covered with transparent glass is formed in the detection pipe 9 at a position corresponding to each reed switch 12 so that the inside of the liquid level detection unit 7 can be visually confirmed. Yes.

  FIG. 3 shows a refrigerant circulation circuit diagram of the first embodiment of the refrigeration apparatus RU shown in FIG. The configuration of FIG. 3 includes three compressors 1A, 1B, 1C and three condensers for cooling the evaporators 5A, 5B, 5C, 5D, and 5E provided in the five showcases SC, respectively. This is a condensing unit CU configuration including 2A, 2B, and 2C. The receiver tank 3 includes the liquid level detection unit 7 described above. Reference numeral 6 denotes the above open / close valve, which is called a solenoid valve. Reference numerals 4A, 4B, 4C, 4D, and 4E denote electric expansion valves that serve as decompression portions provided in the inlet pipes of the evaporators 5A, 5B, 5C, 5D, and 5E, respectively. Reference numeral 17 denotes an oil separator for separating oil from the refrigerant compressed by the compressors 1A, 1B, and 1C. Reference numeral 18 denotes an accumulator that acts to accumulate liquid refrigerant contained in the gas refrigerant returning from the evaporators 5A, 5B, 5C, 5D, and 5E to the compressors 1A, 1B, and 1C. The evaporators 5A, 5B, 5C, 5D, and 5E are respectively provided with cooler air circulation fans F1, F2, F3, F4, and F5, and the cool air cooled by the evaporators 5A, 5B, 5C, 5D, and 5E, The food is circulated in the showcase SC to cool the food. Further, condenser fans 2A, 2B, and 2C are provided with condenser fans F10, F20, and F30, respectively, for promoting heat exchange.

  Temperature sensors 19A, 19B, 19C for detecting the temperatures of the respective evaporators 5A, 5B, 5C, 5D, 5E of the five showcases SC or the temperatures of the respective cooled parts such as the food storage rooms of the five showcases SC , 19D, 19E. The control unit 16 has a signal line from each reed switch 12, a signal line from the temperature sensors 19A, 19B, 19C, 19D, and 19E on the input side, various sensors 21A such as an ambient temperature sensor, and a part to be cooled when the store is closed. A signal line from the night cover switch 21B that operates when the night cover is covered is connected to the operation unit 23 of the manual operation switch. Further, on the output side of the control unit 16, the compressors 1A, 1B, 1C, the electric expansion valves 4A, 4B, 4C, 4D, 4E, the electromagnetic valve 6, and the blowers F1, F2, F3 for cold air circulation, F4, F5, condenser fans F10, F20, F30, display 22 and the like are connected. The control unit 16 includes a storage unit 16M that stores various types of information, and performs a control operation and a display operation according to an incorporated program.

  The electric expansion valves 4A, 4B, 4C, 4D, and 4E appropriately set the decompressed state of the refrigerant that passes through the operation of the control unit 16 based on the temperature detection of the corresponding temperature sensors 19A, 19B, 19C, 19D, and 19E. Operate to control. Further, the compressors 1A, 1B, 1C, the cool air circulation fans F1, F2, F3, F4, F5 and the condenser fans F10, F20, F30 are also detected by the temperature sensors 19A, 19B, 19C, 19D, 19E. By the operation of the control unit 16 based on the above, the rotation speed is appropriately controlled and ON-OFF is controlled. Further, the compressors 1A, 1B, and 1C, the cool air circulation fans F1, F2, F3, F4, and F5, and the condenser fans F10, F20, and F30 have rotation speeds according to signals from the sensor 21A and the night cover switch 21B. Appropriate control is performed and ON-OFF is controlled.

  In the cooling operation of the showcase SC, the refrigerant compressed by the compressors 1A, 1B, and 1C passes through the oil separator 17 and is condensed by the condensers 2A, 2B, and 2C, and a receiver tank (also referred to as a receiver) 3 Then, the electric expansion valves 4A, 4B, 4C, 4D, and 4E are divided through the electromagnetic valve 6 and flow into the evaporators 5A, 5B, 5C, 5D, and 5E. The cold air cooled by the evaporators 5A, 5B, 5C, 5D, and 5E by the refrigerant evaporation in the evaporators 5A, 5B, 5C, 5D, and 5E is cooled by the cooler air circulation fans F1, F2, F3, F4, and F5. Each part to be cooled such as a food storage room of the showcase SC is cooled. The refrigerant that has left the evaporators 5A, 5B, 5C, 5D, and 5E returns to the compressors 1A, 1B, and 1C through the accumulator 18 and is compressed again, and the above circulation is repeated.

  The refrigeration apparatus RU according to the present invention performs the refrigerant recovery operation periodically according to a timer and a program incorporated in the control unit 16 until a predetermined time or a predetermined condition is satisfied. As one of the methods, the refrigerant recovery operation is performed in a time zone after the daily business hours of the store where the showcase SC is installed (so-called closed time zone). Alternatively, when the store where the showcase SC is installed is open 24 hours, the refrigerant recovery operation is performed during a time period when the number of customers during daily business hours is small. Alternatively, the refrigerant recovery operation is performed after the defrosting operation of each of the evaporators 5A, 5B, 5C, 5D, and 5E, which is performed daily or as appropriate, is completed.

  In the present invention, in order to effectively perform the refrigerant recovery operation, the receiver tank 3 is made to be more than the refrigerant pipe RP1 that connects the receiver tank 3 and the electric expansion valves 4A, 4B, 4C, 4D, and 4E that are decompression units. It is placed at a high position.

  The refrigeration unit RU includes a refrigerant circuit that does not include the electromagnetic valve 6 and a refrigerant circuit that includes the electromagnetic valve 6. First, the refrigerant circuit without the electromagnetic valve 6 will be described. In the refrigerant recovery operation, the electric expansion valves 4A, 4B, 4C, 4D, and 4E are forcibly closed by the operation of the control unit 16, and the compressors 1A, 1B, and 1C are operated for a certain period of time. Alternatively, the compressors 1A, 1B, and 1C are operated until a predetermined condition is satisfied, and an operation of collecting the refrigerant in the refrigerant circuit of the refrigeration apparatus RU in the receiver tank 3 is performed.

  First, a case where the refrigerant recovery operation is performed by operating the compressors 1A, 1B, and 1C for a certain time will be described. In this refrigerant recovery operation, the electric expansion valves 4A, 4B, 4C, 4D, and 4E are closed, and more than the refrigerant pipe RP1 that connects the receiver tank 3 and the electric expansion valves 4A, 4B, 4C, 4D, and 4E. Since the receiver tank 3 is arranged at a high position, the refrigerant in the refrigerant circuit of the refrigeration apparatus RU is stored in the receiver tank 3 and the refrigerant pipe RP1. In general, the receiver tank 3 is installed outside the store (outdoor) as a condensing unit CU, while the evaporator 5 (showcase) is installed inside the store (indoor), so Since the refrigerant pipe RP becomes longer, the refrigerant pipe RP1 becomes longer accordingly. As a result, when the refrigerant is recovered, the refrigerant can be stored not only in the receiver tank 3 but also in the refrigerant pipe RP1, so that the receiver tank 3 itself can be downsized.

  After the refrigerant recovery operation is completed by the operation of the control unit 16, the liquid level detection unit 7 detects the refrigerant liquid level recovered in the receiver tank 3. As the liquid level in the receiver tank 3 rises due to the refrigerant recovery operation, the float 10 of the liquid level detection unit 7 rises, so that the reed switch 12 at the position corresponding to the magnet 11 is actuated, thereby measuring Information (measured values) is obtained and stored in the storage unit 16M. If the predetermined reed switch 12 is activated after the refrigerant recovery operation, the control unit 16 reads out the measurement information (measured value) and the specified amount information (specified value) stored in the storage unit. Thus, by comparing the two, it is determined whether or not the specified amount of refrigerant is held in the refrigeration apparatus RU. Thus, if the measurement information (measurement value) is equal to or greater than the prescribed amount information (defined value), it is determined that the prescribed amount of refrigerant is held in the refrigeration apparatus RU. Further, when the measurement information (measured value) does not reach the specified amount information (specified value), the control unit 16 determines that the refrigerant of the refrigeration apparatus RU is insufficient. The determination result of the measurement information (measurement value) at this time is displayed on the display unit 22.

  As a specific operation, as shown in FIG. 6, when eight reed switches 12 are arranged, for example, the sixth reed switch 12 from the bottom is activated by the rise in the liquid level. If the seventh reed switch 12 is not activated, the measurement information (measured value) that the sixth reed switch 12 is activated is stored in the storage unit 16M of the control unit 16, and the control unit 16 Then, by comparing the measurement information (measured value) with the specified amount information (specified value) stored in the storage unit, it is determined that the specified amount of refrigerant is held in the refrigeration apparatus RU. Further, if the fifth reed switch 12 from the bottom is activated but the sixth reed switch 12 from the bottom is not activated, the measurement information (measured value) does not reach the specified amount information (specified value). It is time, and the control unit 16 determines that the refrigerant of the refrigeration apparatus RU is insufficient.

  As described above, after the control unit 16 performs the comparison determination between the measurement information (measured value) and the specified amount information (specified value), the operation of the control unit 16 forcibly drives the electric expansion valves 4A, 4B, 4C, 4D, and 4E are released from the closed state, and are ready for the cooling operation of the showcase SC to be started next.

  The specified amount information (specified value) may be stored in the storage unit as a numerical value by an external input device in advance. However, when the showcase SC is installed in a store, a test run is performed after a predetermined amount of refrigerant is filled as an initial value. The liquid level measured by the liquid level detection unit 7 in the refrigerant recovery operation at 100 may be 100%, for example, a value of 80% thereof may be defined amount information (specified value). That is, the refrigerant recovery operation is performed in this test operation, the float 10 of the liquid level detection unit 7 is raised, and the value of the uppermost reed switch 12 operated by the magnet 11 is set to 100%. Then, 80% of the value may be stored (stored) in the storage unit 16M as the specified amount information (specified value).

  Further, the control unit 16 causes the electric expansion valves 4A, 4B, 4C, 4D, and 4E to be fully closed, and sets the compressors 1A, 1B, and 1C to predetermined conditions, for example, regularly or irregularly for a certain period of time. Alternatively, the amount of refrigerant stored in the receiver tank 3 per unit time is measured, the refrigerant is operated until the amount of the refrigerant reaches the saturation region, and the refrigerant recovery operation is performed. The refrigerant in the refrigerant circuit of the refrigeration unit RU Can also be collected in the receiver tank 3. Since the distance from the condensing unit CU to the showcase SC is long, the amount of refrigerant in the refrigerant circuit of the refrigeration apparatus RU is large. For this reason, a long refrigerant recovery operation time is required. The reed switch 12 is operated sequentially from the lower level to the higher level due to the rise in the liquid level due to the refrigerant recovery operation, but a certain level of the reed switch 12 is operated, but the higher level reed switch 12 is operated even after a predetermined time has elapsed. If not, it can be assumed that a predetermined condition is satisfied by the operation of the control unit 16. This is a predetermined condition when the compressors 1A, 1B, and 1C are operated until a predetermined condition is satisfied. And the measurement information (measurement value) at that time is memorize | stored in the memory | storage part 16M of the control part 16, and the control part 16 compares this measurement information (measurement value) and specified amount information (specified value) similarly to the above. Thus, it is determined whether or not a specified amount of refrigerant is held in the refrigeration unit RU.

  As described above, the control unit 16 performs the refrigerant recovery operation, and displays the measurement information (measured value) and the specified amount information (specified value) at that time on the display unit 22. In this display form, numerical values and / or graphs and tables are displayed on the display 22A. FIG. 8 is a relationship diagram between the liquid level of the refrigeration unit RU and the refrigerant filling amount. Specifically, the relationship between the liquid level of the receiver tank 3 and the ambient temperature of the refrigeration unit RU (condensing unit CU). is there. From this figure, it can be seen that the liquid level decreases as the ambient temperature increases at 100%, 90%, and 80% of the rated refrigerant charge. The receiver tank 3 has an internal volume of 45L and an inner diameter of 254.6 mm. This relationship diagram can be displayed by the switch of the operation unit 23 connected to the control unit 16 for use in charging the refrigerating apparatus RU for the first time or refilling the refrigerant. Moreover, it is also possible to measure the charging amount of the refrigerant based on the correlation equation shown in FIG.

  In addition to this, the display unit 22 compares the measurement information (measured value) with the specified amount information (specified value), and turns on the blue light that is turned on when the refrigerant exceeding the specified amount is held in the refrigeration unit RU. LED 22D, red LED 22C that lights or flashes when it is determined that the refrigerant in the refrigeration unit RU has reached the minimum level, and orange or yellow when it is less than the specified amount but does not reach the minimum level The LED 22B that is turned on is provided.

  Further, the operation of the refrigeration apparatus RU can be set by a switch of the operation unit 23, and the setting state is displayed on the display unit 22. As the operation setting of the refrigeration unit RU, for example, the cooling temperature setting of the cooled parts of each showcase SC, the setting of the start and end of the slow frost operation of the evaporators 5A, 5B, 5C, 5D, and 5E, the refrigerant recovery operation start For example, setting the time and end time. These set values can be displayed on the display unit 22 by the operation of the control unit 16 based on the switch of the operation unit 23.

  As described above, the control unit 16 measures the storage amount per unit time of the refrigerant stored in the receiver tank 3 periodically or irregularly for a certain period of time, and the storage amount reaches a saturation region. A first control unit 16A that performs the refrigerant recovery operation and a second control unit 16B that transmits a predetermined display signal to a remote control device 20 different from the control unit 16A in conjunction with a predetermined display on the display unit 22. doing. The remote control device 20 performs display in conjunction with the display on the display unit 22 by the operation of the second control unit 16B.

  Further, as one of the display methods of the display unit 22, when eight reed switches 12 are arranged as shown in FIG. 6, twelve pieces of reed switches 12 corresponding to each reed switch 12 are arranged. The LED is provided, and the float 10 is raised by the refrigerant recovery operation, so that the LEDs corresponding to the reed switch 12 sequentially operated by the magnet 11 among the 12 LEDs are sequentially turned on. As a result, all the LEDs corresponding to the reed switches 12 below the liquid level are lit, so that the lit LEDs are displayed as a bar graph.

  And when the refrigerant | coolant of refrigeration unit RU runs short and it reaches the minimum level, the lowest LED can be turned on or blinked, and a warning display of refrigerant shortage can be performed. Accordingly, the first control unit 16A performs control to perform a predetermined display on the display unit 22 based on at least one of the measurement information (measurement value) of the liquid level or the change in the value of the liquid level.

  As another method of displaying on the display unit 22, as shown in FIG. 9, the initial refrigerant charging amount is set to 100%, and this is stored in the storage unit 16M. On the other hand, for each refrigerant recovery operation, measurement information (measurement value) measured by the rise of the float 10 is stored in the storage unit 16M, and the numerical value of the display unit 22 and / or the display 22A such as a graph or a table is used in FIG. As shown in the figure, it is easy to grasp the refrigerant decrease state by displaying the refrigerant decrease state in a graph. When the refrigerant decrease rate is large, it is possible to recognize that the refrigerant leaks severely, and to take countermeasures quickly. It will be something that can be done.

  As described above, there are various display forms, but the state of the refrigerant charging amount at that time is grasped by the display by one or a combination of the display forms, and the amount has been reduced to a predetermined amount (specified value) that requires refrigerant replenishment. Is displayed on the display unit 22, and the manager looks at this to determine whether or not refrigerant replenishment is necessary, and measures for repairing refrigerant leakage or the like.

  Next, in the refrigeration apparatus RU, a refrigerant circuit provided with an electromagnetic valve 6 that closes the refrigerant pipe RP1 that connects the receiver tank 3 and the decompression unit 4 (electric expansion valves 4A, 4B, 4C, 4D, and 4E) will be described. As described above, in order to close the electric expansion valves 4A, 4B, 4C, 4D, and 4E to the fully closed state, the accuracy of the electric expansion valves 4A, 4B, 4C, 4D, and 4E must be significantly increased. In other words, the electric expansion valve becomes expensive. For this reason, in order to suppress the cost increase by adopting popular electric expansion valves 4A, 4B, 4C, 4D, and 4E, a method of providing the electromagnetic valve 6 is adopted.

  Thus, in the refrigerant circuit provided with the electromagnetic valve 6, the electromagnetic valve 6 is open in normal cooling operation. In the refrigerant recovery operation, the control unit 16 closes the electromagnetic valve 6 and operates the compressors 1A, 1B, and 1C for a predetermined time or until the compressors 1A, 1B, and 1C satisfy a predetermined condition. The operation is performed to recover the refrigerant in the refrigerant circuit of the refrigeration unit RU to the receiver tank 3. In this refrigerant recovery operation, the electromagnetic valve 6 is closed instead of closing the electric expansion valves 4A, 4B, 4C, 4D, and 4E, so that the refrigerant in the refrigerant circuit is the receiver tank 3, the receiver tank 3, and the electromagnetic valve 6 Is stored in the refrigerant pipe RP1. After the refrigerant recovery operation is terminated by the operation of the control unit 16, the liquid level detection unit 7 detects the refrigerant liquid level recovered in the receiver tank 3. The operation of detecting the refrigerant liquid level by the liquid level detector 7 is the same as described above. Further, the relationship between the control unit 16, the display unit 22, and the remote control device 20 and the operations related thereto are the same as described above.

  FIG. 4 shows a refrigerant circulation circuit diagram of the second embodiment of the refrigeration apparatus RU. The difference from the refrigerant circulation circuit diagram of FIG. 3 is that each oil separator 17A, 17B, 17C is connected by a refrigerant pipe corresponding to each compressor 1A, 1B, 1C, and corresponding to each oil separator 17A, 17B, 17C. That is, the condensers 2A, 2B, and 2C are connected by refrigerant piping. Other configurations are the same as those in the refrigerant circulation circuit diagram of FIG. 3, and the same portions as those in the refrigerant circulation circuit diagram of FIG. The refrigerant recovery operation and other configurations and operations are the same as those described with reference to the refrigerant circulation circuit diagram of FIG. 3, and therefore, the description is based on the refrigerant circulation circuit diagram of FIG.

  As shown in FIG. 9, when the initial refrigerant charge amount is set to 100%, according to the conventional one, detection is performed in a state where the refrigerant amount is reduced and the refrigerant amount is reduced to approximately 60% to 40%. In addition, the amount of refrigerant charged in advance in the refrigeration unit RU must be increased excessively. On the other hand, according to the present invention, since the refrigerant shortage state is detected by the liquid level detection unit 7 after the refrigerant recovery operation, the refrigerant amount is reduced to 90% to 80%. Detection can be performed accurately. For this reason, in the liquid level detection according to the present invention, as shown in FIG. 9, the amount of refrigerant charged in the refrigeration unit RU in advance can be reduced, and an extra amount of refrigerant is stored in the refrigeration unit RU. It becomes economical without the need for filling. In the above-described embodiment, the electromagnetic valve 6 has been described as an example. However, the present invention is not limited to this, and the object (effect) of the present invention can be achieved by a manual valve or an expansion valve. .

  The refrigeration apparatus RU according to the present invention is not limited to the configuration shown in the above-described embodiment, but can be applied to various forms, and includes various forms within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Compressor 1A, 1B, 1C ... Compressor 2 ... Condenser 2A, 2B, 2C ... Condenser 3 ... Receiver tank 3A ... Refrigerant storage part 4 ... Decompression part 4A, 4B, 4C, 4D, 4E ... Electric expansion valve 5 ... Evaporator 5A, 5B, 5C, 5D, 5E ... ··· Evaporator 6 ··· Open / close valve 7 ··· Liquid level detector 8A ······ Inlet pipe 8B ······ Exit pipe 9 ··· Detector pipe 9A ··· Inside Pipe 9B ... Communication pipe 9B ... Outlet pipe 9C ... Refrigerant storage space 10 ... Float 11 ... Magnet 12 ... Reed switch 13 ... Lead wire 14 ... Terminal 15 ... Transparent window 16 ... Control unit 16A ... First control unit 16B ... Second control unit 16M ... Memory 17 ... Oil separator 17A, 17B, 17C ... Oil separator 18 ... Accumulator 19A, 19B, 19C, 19D, 19E ... Temperature sensor 20 ... Remote control device 21A ... Various sensors such as ambient temperature sensor 21B ... Night cover switch 22 ... Display unit 22A ... Display of numerical values and / or graphs, tables, etc. 22B, 22C, 22D ... LED
23 ... Operation unit 24 ... LED
25 ... LED
26... Support plate portion 27... Screw 28... Electrical control unit 29... Main control unit 30 ... Memory 31 ... Sound output unit 32 ... Speaker 33 ··· Cooking function control unit 33A ··· IH4 control unit 33B ··· IH5 control unit 33C ··· Heater 6 control unit 33D ··· Grill control unit 33E · · · Fan control unit 35 ··· -Electrical box 35A ... Box body part 35B ... Air duct part 36 ... First housing part 36D ... Duct 36E ... Air inlet 37 ... Second housing part 37D ... Duct 37E ... Air inlet 37T ... Bottom wall 38 ... Third housing part 38D ... Duct 39 ... Top plate 40 ... Fan 40A ... Sirocco fan 40B ... Electric motor 40C ・ ・ ・ Fan case DESCRIPTION OF SYMBOLS 1 ... Air intake port 42 ... Air discharge port 43 ... Intake duct 44 ... Communication duct 45 ... Communication part 46 ... First air discharge port 47 ...・ ・ Second air outlet 48 ・ ・ ・ ・ Guide wall CU ・ ・ ・ ・ Condensing unit F1, F2, F3, F4, F5 ・ ・ ・ ・ Cooling air blower F10, F20, F30 ・ ・ ・ ・ Condenser Blower RP ... Refrigerant piping RP1 Refrigerant piping RU ... Refrigerating equipment SC ... Showcase

Claims (1)

Multiple showcases equipped with evaporators each equipped with an electric expansion valve on the entrance pipe are installed indoors, and the condensing unit is configured so that the refrigerant compressed by the compressor is condensed in the condenser and flows into the receiver tank. In the refrigeration apparatus installed and piped so that the refrigerant in the receiver tank is diverted to each electric expansion valve through a single refrigerant pipe communicating with the receiver tank and each electric expansion valve,
The refrigerant pipe is opened in the cooling operation of the showcase in the downstream part of the refrigerant pipe before the refrigerant pipe is diverted to the electric expansion valves to function as a part of the receiver tank during the refrigerant recovery operation. In operation, there is a single solenoid valve that closes,
In the receiver tank, a plurality of the reed switches are arranged so that the reed switches from the lower order to the higher order are operated by a float with a magnet that rises as the stored refrigerant liquid level rises,
Based on the temperature detection of a temperature sensor that detects the temperature of the cooled part of each showcase, the corresponding electric expansion valve appropriately controls the decompression state of the refrigerant, and the solenoid valve is closed to operate the compressor. An operation for performing a refrigerant recovery operation for recovering the refrigerant to the refrigerant pipe and the receiver tank, and a measured value and a storage unit in which the reed switch is operated in response to a rising liquid level of the receiver tank after the refrigerant recovery operation. A control unit for performing an operation of determining the amount of refrigerant by comparison with a stored liquid level specified value;
The operation of the compressor in the refrigerant recovery operation can be performed for a certain period of time, or even if the reed switch at a position corresponding to the rising liquid level of the receiver tank is operated and a predetermined time has elapsed, It is operation until it does not work,
A display unit configured to display a determination result of the control unit, wherein the display unit is an LED that lights up when the liquid level of the receiver tank is equal to or higher than the specified value; an LED that lights up at a minimum level of refrigerant shortage; An refrigeration apparatus comprising: an LED that is lighter than a predetermined value and higher than the lowest level .

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