JP2011247489A - Refrigeration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration device that enables a compressor to smoothly start up operation, and prevents the compressor from suffering failure due to poor oil lubrication or liquid compression, thus enhancing the reliability of the compressor.SOLUTION: The refrigeration device 100 includes a controller 5. The controller 5 is configured to, according to temperatures of a refrigerant discharged from the compressor 11, switch between two circuits: an injection circuit A which opens and closes a solenoid valve 15 of an injection circuit 2 depending on the operation conditions of the compressor 11; and an injection circuit B which opens and closes the solenoid valve 15 of the injection circuit 2 anytime when the compressor 11 is at start-up, in operation, or shutdown.

Description

  The present invention relates to a refrigeration apparatus having a refrigeration cycle configured by connecting a condensing unit and a load device, and more particularly to a refrigeration cycle apparatus designed to improve the reliability of a compressor mounted on the condensing unit. Is.

  DESCRIPTION OF RELATED ART Conventionally, the refrigerating device provided with the refrigerating cycle comprised by connecting a condensing unit (heat source side unit) and a load apparatus (load side unit) is known. As a general type of such a refrigeration apparatus, a compressor circuit, a condenser, an expansion valve and a refrigerant circuit connected by piping, and a part of the refrigerant liquid through a solenoid valve and a throttle device (capillary tube) are used as a compressor. And an injection circuit that flows into the injection port. Since this refrigeration apparatus includes an injection circuit for protecting the discharge temperature of the compressor, the solenoid valve is opened simultaneously with the start of the compressor, and the solenoid valve is controlled to be closed simultaneously with the stop of the compressor. Yes.

  Further, a refrigeration apparatus including a refrigerant circuit in which a rotary compressor, a condenser, an expansion valve, and an evaporator are connected by piping and two injection circuits is disclosed (for example, see Patent Document 1). One injection circuit is configured so that a part of the refrigerant liquid after the condenser outlet flows into the injection port of the compressor via a solenoid valve and a throttle device (capillary tube: small flow rate), and the other injection circuit is These are arranged in parallel with one of the injection circuits, and merge with the injection port of the compressor via a solenoid valve and a throttle device (capillary tube: high flow rate).

  The refrigeration apparatus of Patent Document 1 has a thermostat (temperature switch) in the compressor discharge pipe, and when the compressor is started, the solenoid valve of one injection circuit is opened, and the thermostat is activated as the discharge temperature rises. When a predetermined value is reached, the solenoid valve of one injection circuit is closed and the solenoid valve of the other injection circuit is controlled to open. When the discharge temperature falls and reaches a predetermined value at which the thermostat is turned off, the electromagnetic valve of the other injection circuit is closed and the electromagnetic valve of one injection circuit is controlled to be opened. When the compressor is stopped, both solenoid valves of both injection circuits are controlled to be closed. As a modification of the refrigeration apparatus, if a plurality of thermostats (temperature switches) are used, only one injection circuit and only the other injection circuit can be switched in three stages with both injection circuits.

JP 05-288410 A (pages 4 to 7 etc.)

  In the conventional general refrigeration apparatus, the refrigerant is always injected into the compressor as soon as the compressor is started. In the throttle device of this injection circuit, the flow rate is determined so as to maintain the discharge temperature below the allowable value of the compressor in the operating state where the discharge temperature is highest. Therefore, when the compressor is started, an excessive amount of refrigerant is always injected into the compressor. In addition, when the compressor is operating, when the high pressure is low (in other words, the condensation temperature is low) and the refrigerant gas temperature sucked into the compressor is low, that is, the refrigerant gas temperature at the compressor discharge portion is most unlikely to rise. In this state, an excessive amount of refrigerant is injected into the compressor. Therefore, the compressor of such a refrigeration apparatus has a high risk of liquid compression occurring within the operating range and failure.

  The refrigeration apparatus as described in Patent Document 1 uses one injection circuit as a method for determining the flow rate of a throttling device for an injection circuit provided in parallel, in order to prevent poor lubrication due to the refrigerant being dissolved in the lubricating oil. The flow rate is determined so that the difference between the lubricating oil temperature in the compressor and the refrigerant condensing temperature in the condenser is a predetermined value or more (for example, 5 ° C.). The flow rate of the throttle device of the other injection circuit is determined so as to maintain the refrigerant gas temperature of the compressor discharge section below the allowable value of the compressor.

  However, in the compressor, liquid refrigerant flows in from the injection circuit by the two-phase mixed gas, and when the difference between the refrigerant gas temperature in the compressor discharge section and the lubricating oil temperature disappears, the refrigerant dissolves in the lubricating oil. It will be defective and the inside of the compressor will be worn. Therefore, the flow rate determination method for one injection throttling device does not take into account the refrigerant gas temperature of the compressor discharge section, so the risk of poor lubrication cannot be excluded and is sufficient from the viewpoint of compressor protection. I can't say that.

  Further, in the case of using the injection circuit in parallel, the number of parts such as a solenoid valve, a capillary tube, and an injection pipe increases, so that the product cost increases. Further, the same applies to the modification described in Patent Document 1 (configuration in which the injection is switched in three stages). Since a plurality of thermostats are required, the product cost is further increased.

  The present invention has been made in order to solve the above-described problems. The compressor can be started and operated smoothly, and the compressor can be trusted by suppressing the failure of the compressor due to liquid compression or oil lubrication failure. An object of the present invention is to provide a refrigeration apparatus designed to improve performance.

  A refrigeration apparatus according to the present invention includes a compressor that compresses and discharges a refrigerant, a condenser into which refrigerant discharged from the compressor flows, and a part of the refrigerant that flows out of the condenser into an injection port of the compressor. An injecting injection circuit, a solenoid valve provided in the injection circuit, a condensing unit provided in the injection circuit and having at least a throttling device for depressurizing the refrigerant flowing through the injection circuit; and an outflow from the condenser An expansion valve that decompresses the refrigerant, and a load device that includes at least an evaporator into which the refrigerant decompressed by the expansion valve flows, and the electromagnetic valve of the injection circuit is brought into an operating state of the compressor. A first electric circuit that can be opened and closed in accordance with the solenoid valve of the injection circuit A second electric circuit that can be controlled to open / close in any one of start, operation, and stop of the compressor, and the first electric circuit and the second electric circuit according to the temperature of the refrigerant discharged from the compressor; And a control means for switching between.

  According to the refrigeration apparatus of the present invention, the electric circuit is switched as necessary, so that the compressor can be smoothly operated without being abnormally stopped due to a sudden increase in the discharge temperature of the refrigerant gas. Further, it is possible to suppress a compressor failure caused by liquid compression in which an excessive amount of refrigerant is injected. Furthermore, it is possible to reduce compressor wear due to poor lubrication caused by the refrigerant being dissolved in the lubricating oil.

It is a schematic refrigerant circuit diagram which shows an example of the refrigerant circuit of the freezing apparatus which concerns on Embodiment 1 of this invention. It is a schematic electric circuit diagram which shows an example of a part of electric circuit of the freezing apparatus which concerns on Embodiment 1 of this invention. It is the graph which showed the temperature change example of the refrigerant gas detected by the thermostat at the time of the compressor starting in the injection circuit B, and a driving | operation. It is the graph which showed the temperature change example of the refrigerant gas detected by the thermostat at the time of the compressor starting in the injection circuit A, and a driving | operation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic refrigerant circuit diagram illustrating an example of a refrigerant circuit of the refrigeration apparatus 100 according to Embodiment 1 of the present invention. FIG. 2 is a schematic electric circuit diagram showing an example of a part of the electric circuit of the refrigeration apparatus 100. FIG. 3 is a graph showing an example of a change in the temperature of the refrigerant gas detected by the thermostat 22 during the start-up and operation of the compressor in the injection circuit B. FIG. 4 is a graph showing an example of the temperature change of the refrigerant gas detected by the thermostat during the start-up and operation of the compressor in the injection circuit A. The refrigerant circuit configuration and operation of the refrigeration apparatus 100 will be described with reference to FIGS. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  The refrigeration apparatus 100 is used as a refrigeration cycle apparatus (for example, an air conditioner, a showcase, a refrigerator, a freezer, etc.) equipped with a refrigeration cycle for circulating a refrigerant. As shown in FIG. 1, the refrigeration apparatus 100 includes a condensing unit (heat source side unit) 10 and a load device (load side unit) 30. The condensing unit 10 and the load device 30 are connected and communicated with each other through a refrigerant pipe 1 including a gas pipe and a liquid pipe. In addition, in FIG. 1, although the case where each of the condensing unit 10 and the load apparatus 30 is one is shown as an example, the number of installation is not limited and each of the condensing unit 10 and the load apparatus 30 is Two or more units may be used.

  In the condensing unit 10, an accumulator (gas-liquid separator) 14, a compressor 11, a condenser 12, and a liquid receiver 13 are sequentially connected by piping. Further, the condensing unit 10 branches from a pipe on the downstream side of the liquid receiver 13, and the injection port of the compressor 11 is connected via a solenoid valve (first solenoid valve) 15 and a throttling device (capillary tube) 16. An injection circuit 2 connected to (not shown) is provided. A thermostat (temperature switch) 21 is provided on the downstream pipe (discharge side pipe) of the compressor 11. In addition, a thermostat (temperature switch) 22 is provided at a portion of the compressor 11 that most detects the compressed high-temperature refrigerant gas temperature.

  The accumulator 14 is provided on the suction side of the compressor 11 and separates the flowing refrigerant into a gas refrigerant and a liquid refrigerant and stores surplus refrigerant. The compressor 11 sucks the refrigerant flowing through the refrigerant pipe 1 and compresses the refrigerant to be in a high temperature / high pressure state. For example, the compressor 11 is configured to have a type whose rotation speed is controlled by an inverter and capacity is controlled. Good. The condenser 12 performs heat exchange between a heat medium such as air supplied from a blower (not shown) provided near the condenser 12 and the refrigerant to condense and liquefy the refrigerant. The liquid receiver 13 stores the refrigerant condensed and liquefied by the condenser 12. The liquid receiver 13 is connected to the electromagnetic valve 15 through the injection circuit 2 and is connected to the electromagnetic valve 31 of the load device 30 through the refrigerant pipe 1.

  The injection circuit 2 has a function of controlling the refrigerant gas temperature at the discharge portion of the compressor 11. The solenoid valve 15 is controlled to open and close, and may or may not conduct the refrigerant to the injection circuit 2. The expansion device 16 depressurizes the refrigerant flowing through the injection circuit 2.

  In the case of the electric circuit of the injection circuit B shown in FIG. 2, the thermostat 21 (the contact 26 </ b> C shown in FIG. 2) is turned on (energized) when the temperature of the refrigerant discharged from the compressor 11 is high. Then, the controller (solenoid valve coil) 21R is energized by turning on the contact 26C, and opens the solenoid valve 15. In the case of the electric circuit of the injection circuit B shown in FIG. 2, the thermostat 21 is turned off (non-energized) when the temperature of the refrigerant discharged from the compressor 11 is low. Then, the controller 21R is de-energized by turning off the contact 26C, and closes the solenoid valve 15.

  The thermostat 22 (49C in FIG. 2) operates when the temperature of the refrigerant discharged from the compressor 11 exceeds an allowable value, that is, the contact point 49C is separated (non-energized). Since the contact 49C is separated, the energization to the electromagnetic contactor 52C downstream thereof is cut off. Since the electromagnetic contactor 52C is an ON / OFF contact point of the compressor 11, the compressor 11 is turned off when the power is cut off, and the compressor 11 is prevented from being damaged due to abnormal discharge temperature.

  On the load device 30, an electromagnetic valve 31, an expansion valve 32, and an evaporator 33 are sequentially connected by piping. The solenoid valve 31 is controlled to be opened and closed so that the refrigerant flows or does not flow through the expansion valve 32 and the evaporator 33. The expansion valve 32 decompresses the refrigerant to expand it. The expansion valve 32 may be composed of, for example, an electronic expansion valve or a temperature expansion valve whose opening degree can be variably controlled. The evaporator 33 performs heat exchange between a heat medium such as air supplied from a blower (not shown) provided in the vicinity of the evaporator 33 and the refrigerant to evaporate the refrigerant.

  Therefore, the refrigeration apparatus 100 includes a refrigerant circuit in which the compressor 11, the condenser 12, the liquid receiver 13, the electromagnetic valve 31, the expansion valve 32, the evaporator 33, and the accumulator 14 are sequentially connected through the refrigerant pipe 1. The compressor 11, the condenser 12, the liquid receiver 13, the electromagnetic valve 15, the expansion device 16, and the refrigerant circuit (injection circuit) in which the injection port of the compressor 11 is sequentially arranged in the refrigerant pipe 1 and the injection circuit 2. It has a refrigeration cycle. In FIG. 1, a state in which the liquid receiver 13 and the accumulator 14 are mounted on the refrigeration apparatus 100 is shown as an example, but the liquid receiver 13 and the accumulator 14 are not essential to the refrigeration apparatus 100.

The operation of the refrigeration apparatus 100 will be described.
The refrigerant flowing into the compressor 11 is compressed by the compressor 11 and discharged from the compressor 11 as a high-temperature / high-pressure refrigerant gas (discharge gas). The refrigerant discharged from the compressor 11 flows into the condenser 12 through a pipe to which the thermostat 21 is attached. The refrigerant flowing into the condenser 12 exchanges heat with the heat medium supplied to the condenser 12 to dissipate heat and liquefy. A part of the liquefied refrigerant liquid flows out of the condensing unit 10 through the liquid receiver 13. The refrigerant liquid flowing out from the condensing unit 10 flows into the load device 30.

  The refrigerant liquid flowing into the load device 30 passes through the electromagnetic valve 31 and is throttled by the expansion valve 32 to be in a two-phase mixed gas state. The refrigerant in the two-phase mixed gas state flows into the evaporator 33. The refrigerant in a two-phase mixed gas state that has flowed into the evaporator 33 exchanges heat with the heat medium supplied to the evaporator 33 to absorb heat and gasify. The gasified refrigerant gas flows out of the load device 30 and returns to the condensing unit 10. The refrigerant gas that has returned to the condensing unit 10 passes through the accumulator 14 and is sucked into the compressor 11 again.

  On the other hand, a part of the refrigerant liquid flowing out from the liquid receiver 13 flows into the injection circuit 2 through a pipe branched from the downstream of the liquid receiver 13. The refrigerant liquid flowing into the injection circuit 2 passes through the electromagnetic valve 15 and is throttled by the throttle device 16 to be in a two-phase mixed gas state. The refrigerant in the two-phase mixed gas state is injected into the injection port of the compressor 11. The refrigeration apparatus 100 repeats this operation. The description has been made assuming that both the solenoid valve 15 and the solenoid valve 31 are controlled to be opened.

  As shown in FIG. 2, the electric circuit of the refrigeration apparatus 100 instructs the operation and stop of the compressor 11 and the contact 49 </ b> C of the thermostat 22 that is a compressor discharge temperature protection device between the power line R and the power line T phase. The electromagnetic contactor 52C to be connected is wired in series. In other words, when the detected refrigerant gas temperature exceeds a predetermined upper limit temperature (T1 shown in FIG. 3), the thermostat 22 opens the contact 49C (non-energized), and the electromagnetic contactor 52C receiving it opens the compressor 11 Is supposed to stop. Further, the thermostat 22 is closed (energized) at a temperature at which the detected refrigerant gas temperature is lower than a predetermined upper limit temperature (T1 shown in FIG. 3) and is safe even when the compressor 11 is restarted. Yes.

  In addition, a controller 5 that electrically commands switching of the injection circuit A and the injection circuit B and a controller (electromagnetic valve coil) 21R that opens and closes the electromagnetic valve 15 of the injection circuit 2 are in parallel with the electromagnetic contactor 52C. Wired connection. The controller 5 switches between the injection circuit A and the injection circuit B according to the temperature of the refrigerant gas discharged from the compressor 11 (broken line arrow shown in FIG. 2).

  Here, the injection circuit A means that the solenoid valve 15 is always opened when the compressor 11 is started and operated, and the solenoid valve 15 is closed when the compressor 11 is stopped (A shown in FIG. 2). ). That is, the injection circuit A means a first electric circuit that can open and close the electromagnetic valve 15 of the injection circuit 2 according to the operating state of the compressor 11. The injection circuit B is controlled so that the contact 26C of the thermostat 21 is connected in series with the upstream of the controller 21R that opens and closes the electromagnetic valve 15 (B shown in FIG. 2). That is, the injection circuit B means a second electric circuit that can control opening and closing of the electromagnetic valve 15 in any of starting, operating, and stopping of the compressor 11.

  The contact 26C is closed (energized) when the temperature of the pipe downstream of the compressor 11 rises and the thermostat 21 exceeds a predetermined set value, and the temperature of the pipe downstream of the compressor 11 drops, and the thermostat 21 When it is below the set value, it is open (not energized). Further, upstream of the controller 21R that opens and closes the electromagnetic valve 15 of the injection circuit 2, there is a contact 6C that actually switches between the injection circuit A and the injection circuit B in response to a command from the controller 5. In the following description, switching between the injection circuit A and the injection circuit B may be simply referred to as switching of the injection circuit.

  The switching of the injection circuit will be described. 3 and 4, the horizontal axis represents time t, and the vertical axis represents temperature T (refrigerant gas temperature detected by the thermostat 22). Further, T1 indicates the operating temperature of the thermostat 22 <contact 49C open (non-energized)>, T2 indicates the set temperature of the thermostat 21 <closed contact 26C (energized)>, and T3 indicates the set temperature of the thermostat 21 <contact 26C open (closed). Non-energized)>, respectively, and the set temperature has a relationship of T1> T2> T3. Furthermore, the pattern X, the pattern Y, the pattern Q, and the pattern R indicate the temperature change (one example) of the refrigerant gas detected by the thermostat 22 from the start of the compressor 11 to the operation (on the way).

  The pattern X shows an example of the refrigerant gas temperature detected by the thermostat 22 during startup and operation of the compressor 11 in the case of the injection circuit B. As represented by the pattern X, the refrigerant gas temperature is low when the compressor 11 is started, and gradually rises with time. Then, the refrigerant gas temperature exceeds the set temperature of T3 and T2, and rises to between T1 and T2.

  The thermostat 21 is attached to the discharge side piping of the compressor 11. Therefore, a temperature difference is generated between the refrigerant gas temperature detected by the thermostat 21 and the refrigerant gas temperature detected by the thermostat 22. Therefore, the refrigerant gas temperature rises to between T1 and T2. Therefore, the refrigerant gas temperature detected by the thermostat 21 becomes equal to T2, and the contact 26C is closed (energized), so that the electromagnetic valve 15 is opened. If it does so, refrigerant gas will be cooled by injection which flows in from the injection port of compressor 11, and will become stable temperature.

  The pattern Y shows an example of an abnormal stop of the compressor in the case of the injection circuit B, that is, an example of the refrigerant gas temperature detected by the thermostat 22 when the refrigerant gas temperature at the discharge portion of the compressor 11 rises rapidly. . The refrigerant gas temperature at the start of the compressor 11 rises rapidly when the temperature of the refrigerant gas sucked into the compressor 11 is high and the evaporation temperature is low. Specifically, the lengths of the load device 30 and the connection pipe (refrigerant pipe 1) cannot be controlled by the condensing unit 10, and vary depending on the environment and equipment to be installed and the contractor.

  Therefore, the temperature of the refrigerant gas sucked into the compressor 11 tends to increase when the set opening of the expansion valve 32 of the load device 30 is small and the connection pipe between the load device 30 and the condensing unit 10 is long. is there. In the control in which the electromagnetic valve 15 of the injection circuit 2 is closed and the compressor 11 is activated (the control circuit in which the compressor 11 is activated from the injection circuit B), the refrigerant gas temperature further increases. Therefore, in the refrigeration apparatus 100, when the refrigerant gas temperature rapidly rises and reaches T1, the contact 49C on the electric circuit is opened, the operation of the compressor 11 is stopped, and the electromagnetic valve 15 of the injection circuit 2 is closed. Yes.

  Depending on the product specifications, the contact 49C may be opened and the compressor 11 may stop, and an abnormality alarm may be issued at the same time. Further, the compressor 11 is stopped until the set temperature <49C closed (energization)> at which the thermostat 21 is restored, that is, the safe temperature at which the compressor 11 may be started again.

  The pattern Q shows an example in which injection is performed simultaneously with the start of the compressor 11 in the case of the injection circuit A. As shown in the pattern Q, the refrigerant gas temperature at the start-up of the compressor 11 is injected at the same time as the start-up, and thus rises more smoothly than the temperature rise of the pattern X, and becomes a stable temperature.

  The pattern R shows an example of a compressor failure in the case of the injection circuit A, that is, an example in which an excessive injection enters simultaneously with the start of the compressor 11. As shown in the pattern R, the refrigerant gas temperature at the start-up of the compressor 11 is low when the refrigerant gas temperature sucked into the compressor 11 is low and the evaporation temperature is high. That is, the temperature of the refrigerant gas sucked into the compressor 11 tends to decrease when the set opening degree of the expansion valve 32 of the load device 30 is large and the connection pipe between the load device 30 and the condensing unit 10 is short. is there.

  Therefore, the compressor 11 does not increase the discharge temperature due to excessive injection and compresses the liquid. In the case of having a detecting means for liquid compression, the liquid back protection is controlled, and the compressor 11 stops protection. However, when the detection means is not provided, the state of liquid compression is always repeated, leading to a failure of the compressor 11. In addition, the compressor 11 is worn due to poor lubricating oil.

  In the case of the pattern Y and the R pattern A, the quality of the goods accommodated in the refrigerator or the freezer may be deteriorated due to the influence of the temperature rise in the refrigerator. Therefore, in the refrigeration apparatus 100, the injection circuit is always switched by commands from the controller 5 so that the patterns X and Z shown in FIGS.

  As described above, according to the refrigeration apparatus 100, the controller 5 that commands the injection circuit to switch as necessary is provided, and the switching command for the injection circuit corresponds to the refrigerant gas temperature of the discharge portion of the compressor 11. Therefore, the compressor 11 can be smoothly operated without being abnormally stopped due to a sudden increase in the discharge temperature of the refrigerant gas. Further, according to the refrigeration apparatus 100, since the injection circuit is switched as necessary, it is possible to suppress a failure of the compressor 11 caused by liquid compression in which an excessive amount of refrigerant is injected. Furthermore, according to the refrigeration apparatus 100, since the injection circuit is switched as necessary, it is possible to reduce wear of the compressor 11 due to poor lubrication caused by the refrigerant being dissolved in the lubricating oil. Therefore, the refrigeration apparatus 100 is highly reliable.

Embodiment 2. FIG.
In the first embodiment, the controller 5 is used to switch the injection circuit, but in the second embodiment, the timer is used to switch the injection circuit. The basic refrigerant circuit configuration and electrical circuit configuration of the refrigeration apparatus according to Embodiment 2 are the same as those of the refrigeration apparatus according to Embodiment 1. In the second embodiment, the difference from the first embodiment will be mainly described, and the same reference numerals as those used in the first embodiment will be used.

  The timer can be set according to the environment where the product (for example, the condensing unit 10) is installed and the specifications of the compressor 11. Therefore, when the compressor 11 is started, the compressor 11 is switched to the injection circuit A until a predetermined time set by the timer elapses, and the injection circuit is changed from A to the injection circuit when the predetermined time set by the timer elapses. Switch to B. When the compressor 11 stops, the timer is reset, so that the above switching control can be repeated. Therefore, the same effect as in the first embodiment can be obtained.

Embodiment 3 FIG.
In the second embodiment, the injection circuit is switched using a timer, but in the third embodiment, the injection circuit is switched using a control board. The basic refrigerant circuit configuration and electrical circuit configuration of the refrigeration apparatus according to Embodiment 3 are the same as those of the refrigeration apparatus according to Embodiment 1. In the third embodiment, the difference from the first embodiment will be mainly described, and the same reference numerals as those used in the first embodiment will be used.

  The control board is composed of a microcomputer and can grasp the operating status of the condensing unit 10 from time to time based on information such as the pressure and temperature of each part in addition to starting / stopping the compressor 11. Therefore, if the control board is used, the switching control of the injection circuit can be performed more efficiently than the timer. Therefore, it is possible to obtain the effects of the second embodiment or more. In addition, the product cost is not significantly increased. The control board may be configured by providing the controller 5 described in Embodiment 1 on the board.

  As described above, according to the refrigeration apparatus according to Embodiments 1 to 3, since the injection circuit is switched as necessary, the compressor 11 does not stop abnormally due to a sudden rise in the discharge temperature of the refrigerant gas, and the operation is performed. It can be done smoothly. In addition, according to the refrigeration apparatus according to Embodiments 1 to 3, since the injection circuit is switched as necessary, failure of the compressor 11 caused by liquid compression in which an excessive amount of refrigerant is injected can be suppressed. Furthermore, according to the refrigeration apparatus according to the first to third embodiments, since the injection circuit is switched as necessary, it is possible to reduce the wear of the compressor 11 due to poor lubrication caused by the refrigerant being dissolved in the lubricating oil. Therefore, the refrigeration apparatus according to Embodiments 1 to 3 is highly reliable.

  DESCRIPTION OF SYMBOLS 1 Refrigerant piping, 2 Injection circuit, 5 Controller, 10 Condensing unit, 11 Compressor, 12 Condenser, 13 Receiver, 14 Accumulator, 15 Solenoid valve, 16 Throttle device, 21 Thermostat, 21R Controller, 22 Thermostat, 26C contact point, 30 load device, 31 solenoid valve, 32 expansion valve, 33 evaporator, 49C contact point, 52C electromagnetic contactor, 100 refrigeration device, A injection circuit, B injection circuit, R power supply line, T power supply line.

Claims (3)

A compressor that compresses and discharges the refrigerant; a condenser into which the refrigerant discharged from the compressor flows in; an injection circuit that causes a part of the refrigerant that flows out of the condenser to flow into an injection port of the compressor; and the injection circuit A condensing unit equipped with at least a throttling device that is provided in the injection circuit, and is provided in the injection circuit and depressurizes the refrigerant flowing through the injection circuit;
An expansion valve that depressurizes the refrigerant that has flowed out of the condenser, and a load device that includes at least an evaporator into which the refrigerant depressurized by the expansion valve flows.
A first electric circuit capable of opening and closing the electromagnetic valve of the injection circuit according to an operating state of the compressor;
A second electric circuit capable of controlling opening and closing of the electromagnetic valve of the injection circuit in any of starting, operating and stopping of the compressor;
Control apparatus which switches said 1st electric circuit and said 2nd electric circuit according to the temperature of the refrigerant discharged from said compressor. A refrigerating device characterized by things. The control means includes
The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is configured by a controller that electrically commands switching of the first electric circuit and the second electric circuit. The control means includes
The refrigeration apparatus according to claim 1, wherein the first electric circuit and the second electric circuit are switched based on a predetermined time set in advance.

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