JPH084680A - Refrigerating device - Google Patents

Abstract

PURPOSE:To restrain the damage of cooling articles and cooling units to a minimum by reducing the capacity of refrigeration for continuing the operation of a compressor on and after the reset of a protective device. CONSTITUTION:A refrigerating device is provided with a refrigerating cycle circuit, a liquid injection circuit 21 and a capacity control system 28, and when a protective device is operated by the abnormality of discharge gas temperature so as to be reset, the fan 10 of a condenser 9 is operated at full speed by the operation of a high-pressure detecting switch 40H for significantly reducing the condensation pressure, and also capacity control valves 31, 32 are opened for reducing the quantity of a circulating refrigerant and for continuing cooling operation. Thus, the gas temperature can be prevented from rising without liquid injection cooling, and operation can be continued without causing failure for cooling articles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating device for cooling a showcase used in a supermarket or the like, a prefabricated refrigerator / freezer for business use, and the like.

[0002]

2. Description of the Related Art Today, CFCs are substances that deplete the ozone layer. Therefore, for environmental protection, there are worldwide regulations that gradually prohibit the use of CFCs that have a high degree of destruction.

As the CFC refrigerant used in the refrigeration system, the CFC refrigerant R12, which has been frequently used in the past, is prohibited from use, and it is unavoidable to use a refrigerant instead of the CFC refrigerant R12.
For example, a refrigerating apparatus using a Freon refrigerant R22 is under study.

In this case, the refrigerant R22 is made to evaporate in the low temperature region (up to -40 ° C.), and has the same cooling capacity as the refrigerant R12. Therefore, the refrigerant compressor (hereinafter abbreviated as a compressor), which plays a central role in the refrigeration system, is overloaded due to the use of the above-mentioned low temperature region of R22 and has a considerably high temperature, so that the inside of the compressor by liquid injection is Cooling is performed.

Cooling by liquid injection is
In the refrigeration cycle, some liquid refrigerant from the receiver tank (receiver) that stores the liquid refrigerant after it has been discharged from the condenser is bypassed by a liquid injection circuit that has a solenoid valve and a capillary tube, and the middle of the cylinder inside the compressor The compressor is guided to a position and vaporized, and the inside of the compressor is cooled by the heat of vaporization at that time. In this method, if the compressor is overloaded for a long period of time, the liquid refrigerant in the receiver tank is exhausted, and liquid injection cannot be performed, the temperature in the compressor becomes a high temperature state exceeding 150 ° C.

At such a high temperature, the winding temperature of the compressor also becomes higher than the limit temperature, which leads to burnout of the compressor due to defective insulation, etc., and it cannot be used.

[0007]

Therefore, the temperature of the discharge gas discharged from the compressor is detected by a temperature sensor such as a discharge gas overheating thermometer, and when a predetermined high temperature is detected, the compressor is stopped. Is provided to protect the compressor from excessive heat.

However, this protection device prioritizes that the cooling articles in the showcase and the refrigerator / freezer are not damaged by the interruption of the cooling operation. Therefore, when the discharge gas temperature decreases, the compressor is automatically restarted. Generally, if the discharge gas superheated thermostat is repeatedly used for ON-OFF operation, the temperature inside the compressor rises and may be damaged.

In the refrigeration system, defrosting is performed at appropriate times. In the case of the hot gas system in which the high-temperature and high-pressure discharge gas from the compressor bypasses the condenser and directly flows into the evaporator, the defroster does not The refrigerant does not flow, so when the amount of frost is large, the liquid refrigerant in the receiver tank is exhausted,
There is also a problem that the liquid injection does not work, the discharge gas temperature rises abnormally, and the compressor stops in the middle of the defrosting operation due to the above-mentioned discharge gas overheating thermometer and the like, which causes a defrosting failure.

In the case of a compressor cooled by liquid injection as described above, the liquid refrigerant in the refrigeration cycle is in a depleted state when the discharge gas superheated thermostat operates once, and therefore liquid injection does not work even if it is restored again. Since the discharge gas temperature becomes high, the compressor stops at the protection device, so that the cooling operation and defrosting cannot be performed, resulting in insufficient cooling and poor defrosting. In such a case, if the protective device is frequently turned on and off,
In some cases, the compressor may be damaged.

Therefore, according to the present invention, even when the compressor becomes in a situation where the protective operation is activated by the discharge gas overheated thermostat and the liquid injection does not work, when the protective device is restored again, the compressor does not have the liquid injection. The present invention provides a refrigeration system capable of performing a cooling operation in which the operation is controlled to continue in a range where the temperature does not become high, and the damage to the cooling object and the refrigeration unit is minimized.

[0012]

SUMMARY OF THE INVENTION The present invention is a liquid injection circuit provided in a refrigeration cycle including at least a compressor, a condenser, a condenser cooling fan, and an evaporator decompression device, and a liquid refrigerant is injected into the compressor. While cooling the compressor, while the temperature of the compressor exceeds a predetermined temperature, in the refrigeration device configured to temporarily stop the compressor in the protection device, a motor for driving the condenser cooling fan, and After the protection device is activated and the compressor is temporarily stopped, when the temperature of the compressor is lowered and the operation of the compressor is restored, a fan control device for rotating the motor for driving the condenser cooling fan at full speed is provided. Be prepared.

Further, the present invention is a liquid injection circuit provided in a refrigeration cycle comprising at least a compressor, a condenser, a condenser cooling fan, and an evaporator decompression device, and a liquid refrigerant is injected into the compressor to form the compressor. While cooling, while the temperature of the compressor exceeds a predetermined temperature, in the refrigeration device configured to temporarily stop the compressor in the protection device,
A capacity control path for returning a part of the high-pressure gas refrigerant discharged from the compressor to the low pressure side of the compressor by bypassing the evaporator, an electric valve provided in the capacity control path, and the protection device. Is operated to temporarily stop the compressor, and then when the temperature of the compressor is lowered and the operation of the compressor is restored, the valve opening / closing control device is opened.

Furthermore, the present invention is a liquid injection circuit provided in a refrigeration cycle comprising at least a compressor, a condenser, a condenser cooling fan and an evaporator decompression device, and a liquid refrigerant is injected into the compressor to form the compressor. While cooling, while the temperature of the compressor exceeds a predetermined temperature, in the refrigeration device configured to temporarily stop the compressor in the protection device,
A motor for driving the condenser cooling fan, a capacity control path for returning a part of the high pressure gas refrigerant discharged from the compressor to the low pressure side of the compressor by bypassing the evaporator, and the capacity control. The condenser cooling fan is driven when the temperature of the compressor is lowered and the operation of the compressor is restored after the motor-operated valve provided in the path and the protection device are activated to temporarily stop the compressor. A cooling operation control device for rotating the motor at full speed and opening the motor-operated valve is provided.

[0015]

Operation Normally, the compressor is cooled and operated by liquid injection. Further, the condenser cooling fan rotates at a certain rotation speed to cool the condenser so that the condensing pressure is such that the required cooling capacity can be exerted.

When the discharge gas temperature becomes abnormally high, the protection device temporarily stops the operation of the compressor. When the protective device returns, the cooling effect due to liquid injection cannot be expected, so if the operation is restarted, the compressor will fail, but in this refrigeration system, the condenser cooling fan will operate at full speed and heat exchange will increase. To reduce the condensing pressure to the pressure corresponding to the set temperature.

Further, the motor-operated valve provided in the capacity control path is opened to partially return the discharged refrigerant directly to the compressor to reduce the circulating refrigerant amount. As a result, the compressor can continue to operate with its capacity reduced, and the rise in temperature of the compressor is suppressed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a Mollier diagram showing a refrigeration cycle in a compressor using a refrigerant R22. here,
This compressor will be described assuming that the allowable operating temperature is 150 ° C.

In the diagram, the gas sucked in at point a is compressed and rises to point c. The compressed high-temperature and high-pressure gas is condensed in the condenser (point d) and then supercooled to point d '. The condensed liquid refrigerant is decompressed by the decompressor (point e),
Then, it is vaporized into gas by the evaporator and is sucked into the compressor.

Therefore, when the refrigerant R22 is used, c
Since the temperature of the spot (gas compression temperature) exceeds 150 ° C., the temperature of the discharged gas is lowered by liquid injection. That is, liquid injection is performed at point b, and b ′
By lowering the temperature to the point and then compressing it to the point c ', the discharge gas temperature can be lowered to 130 ° C or lower, which does not hinder the operation.

As can be seen from this figure, the following two means can be considered to lower the point c. (1) Lower pressure (H 'point) (2) Lower intake gas temperature (a point)

Therefore, in the present invention, the method (1) above is adopted among the above-described two corresponding methods that enable operation in a state in which the discharge gas temperature is lowered without the aid of liquid injection. In order to reduce the condensing pressure to the pressure H ′ at the intersection c ″ of the isotherm line of 130 ° C. and the isentropic line of adiabatic compression, the fan of the condenser is operated at full speed, and the refrigerant circulation amount of the compressor is reduced. Use capacity control operation to reduce heat.

By the way, the refrigerant circuit of the refrigerating apparatus according to the present invention is as shown in FIG. 2, and the electric circuit of the refrigerating apparatus is as shown in FIG.

In FIG. 2, reference numeral 1 denotes a compressor having a liquid injection device, which has a gas refrigerant discharge port 2a and a suction port 2b, and a liquid refrigerant injection port 4 injected by a liquid injection circuit 3 for compression. A pressure pipe 5 for obtaining an operating pressure is connected to the pressure port 5a for the capacity control operation of the machine (in-cylinder bypass system). Reference numeral 6 denotes an oil separator, which separates the lubricating oil from the gas refrigerant and returns the lubricating oil to the compressor 1 through the pipe line 7. The gas refrigerant discharged from the oil separator 6 flows into the condenser 9 through the first solenoid valve (SV) 8. The condenser 9 includes a condenser cooling fan 10 (hereinafter, abbreviated as a cooling fan), and a drive motor 10M thereof whose rotation speed can be variably controlled by a fan control device (48 in FIG. 3) described later. Therefore, the heat exchange capacity of the condenser 9 can be changed, and the condensation pressure can be changed.

A receiver tank 12 for storing the liquefied refrigerant is arranged in the subsequent stage of the condenser 9, and the liquid refrigerant from the tank 12 flows into the indoor unit through a third solenoid valve (SV) 13 and a moisture indicator 14. To do. An evaporator 15 is piped through an expansion valve 16 on the indoor side, and a fourth solenoid valve (S which is closed during cooling operation and opened during defrosting)
V 1) 17 is provided in parallel with the expansion valve 14. Then, the refrigerant evaporated and vaporized by the evaporator 15 is returned to the suction port 2b of the compressor 1 via the strainer 18 and the accumulator 19.

The above-mentioned compressor 1, oil separator 6,
The first solenoid valve 8, the condenser 9, the receiver tank 12, the third solenoid valve 13, the evaporator 15, the strainer 18, the accumulator 19 and the like are sequentially connected in an annular shape by a pipe 20 to form a refrigeration cycle.

Further, in order to defrost the evaporator 15 with hot gas, a hot gas circuit 21 is provided in which the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 bypasses the condenser 9 and directly flows into the evaporator 15. There is. A second electromagnetic valve (SV) 22 that is opened during defrosting and closed during cooling operation is inserted in the hot gas circuit 21.

The above-mentioned liquid injection circuit 3
Connects one end between the receiver tank 12 and the third solenoid valve 13 and uses it as a liquid intake port, and the same electric circuit 3 has a first motor-operated valve (L1) 2 for injection control.
4 and the second electric valve (L2) 25, the first and second capillary tubes 26, 27 are arranged, and first the first electric valve 2
4 is opened and the 2nd motor operated valve 25 is closed, and a predetermined amount of liquid refrigerant is made to flow and it cools. However, if the amount of the refrigerant is insufficient and the cooling effect is weak and the compressor temperature seems to rise, the motor-operated valve 2
The motor-operated valves 24 and 25 are controlled so that 4 is closed and the motor-operated valve 25 is opened to flow a large amount of liquid refrigerant.

28 is a first solenoid valve 8 and a second solenoid valve 22.
Is an auxiliary pipe whose one end is commonly connected to the inlet side of and the high pressure discharge gas refrigerant from the compressor 1 is partially connected to the pressure pipe 5 through the first capacity control valve (V1) 31. Reference numeral 32 denotes a second displacement control valve (V2) 32, one end of which is commonly connected to the outlet end of the first displacement control valve 31, and the other end of which is provided with a strainer 18 and an accumulator 19 via a check valve 33.
Is connected between and. Here, since the first displacement control valve 31 is normally open and the second displacement control valve 32 is closed, the high-pressure refrigerant discharged from the compressor is supplied to the pressure pipe 5 via this control valve 31. The high pressure port 5a of the compressor
Is kept at high pressure, and the compressor with the internal bypass circuit closed is kept at full capacity operation. When the second displacement control valve 32 opens, its high pressure escapes to the low pressure side via the check valve 33, the first displacement control valve 31 also closes, the high pressure port 5a of the compressor 1 becomes low pressure, and the internal bypass. The circuit opens and the compressor operation is reduced to about 60%.

Reference numeral 34 is a high / low pressure switch device for detecting the pressure on the high pressure side and the low pressure side through a pressure detection pipe 36 connected to the refrigeration cycle and a pressure detection pipe 37 connected to the inside of the compressor 1, and detects abnormal high and low pressures. When it does, it has the function of interrupting the operation of the compressor 1 and protecting it. And 38a and 39a are a high pressure manometer and a low pressure manometer on which the detected pressure is respectively displayed. Further, 40 L is a low pressure pressure switch for capacity control, which detects a pressure change in the refrigeration cycle and controls switching between the first capacity control valve 31 and the second capacity control valve 32.

Further, 40H is a high-pressure switch for cooling the condenser fan, which operates when the protective device returns to operation and rotates the condenser-cooling fan 10 at full speed.

Next, the structure of the electric circuit shown in FIG. 3 will be described.

From the three-phase AC power supply to the earth leakage breaker (EB) 4
3, the power is supplied to the compressor (CM) 1 via the power supply terminal plate 44, the power supply terminal plate 44, and the first operation contact piece 45a of the compressor electromagnetic contactor 45 and the thermal relay 46.

A fan controller 48 for controlling the speed (rotation speed) of the drive motor (CF) 10M for the condenser cooling fan is connected to the supply line to the compressor 1.

Reference numeral 49 is a temperature sensor for detecting the outside air temperature, and the fan controller 48 drives the drive motor 10M according to the temperature information.
Is controlled to rotate at full (high) speed in summer and at low speed in winter.

The fan controller 48 is connected with a fan high-speed high-pressure pressure switch 40H and a contact 75d operated by a fourth auxiliary relay which will be described later. When these are closed, the drive motor 10M operates at full speed. When it is opened, it is controlled to be driven at a low speed.

Reference numeral 50 denotes a liquid injection controller (LIC) connected between two power supply lines, and includes a LIC power supply transformer (TR) 51. Reference numeral 52 is a reverse phase prevention relay connected to the power supply line, and the reverse phase connecting piece 52a thereof.
Is normally switched to the A side, and when a reverse phase state occurs, it is switched to the B side shown in the figure, and the power supply reverse phase alarm lamp (RL) 5
Turn on 3.

The control circuit 54 includes the reverse phase prevention relay 52.
Control lines 55a, 5 via two terminals (R, T) of
5b is connected to two of the power supply lines to supply electric power.

Reference numerals 56 and 56 denote operation switches which are interlocked with each other,
57 is a crankcase heater (CH), which is energized by closing the second operating contact piece 45b when the compressor electromagnetic contactor (G) 45 is cut off (when the compressor is stopped). Reference numeral 58 denotes a refrigerator abnormality lamp (RL), which is controlled by the control line 55 so as to be turned on via the first auxiliary relay (R1) 61.
It is connected between a and 55b.

The first auxiliary relay 61 has a self-holding contact 61a, which is connected in series between the control lines 55a and 55b via the self-holding contact 61a and the alarm reset switch 62, and the first auxiliary relay 61a. In parallel with 61,
Second auxiliary relay (R2) 63 and third auxiliary relay (R3)
64 are provided via respective self-holding contacts 63a and 64b.

Reference numeral 65 is a compressor protection thermostat, and 66 is a thermal relay whose contact switches to the left side from the illustrated position when the temperature of the compressor 1 rises excessively. At the time of switching, an overcurrent alarm parallel to the second auxiliary relay 63 is provided. The lamp (RL) 67 lights up. 34H and 34L are high and low pressure switches that detect the internal pressure of the refrigeration cycle system. When the pressure is high, the high pressure switch 34H switches from the illustrated state to the left side, and a high pressure abnormality alarm lamp (RL) in parallel with the third auxiliary relay 64. 6
8 lights up.

By the way, although not shown, the compressor 1 is provided with a discharge gas overheating thermometer or the like which is arranged near the discharge port 2a and detects the temperature of the discharge gas. An auxiliary relay that responds to the discharge gas overheating thermometer is provided, and when it is detected that the temperature of the discharge gas has risen above 130 ° C., the contact 70 of the auxiliary relay is opened.

The contact 70 is the electromagnetic contactor 4 for the compressor.
5 is connected in series, so that the compressor 1
At 0 ° C.), this contact 70 is broken, the compressor electromagnetic contactor 45 is broken, and the first operating contact piece 45a is opened, and the operation of the compressor 1 is stopped.

Further, there is a contact 71 that switches at a predetermined set temperature lower than the temperature at which the discharge gas overheated thermostat works, and when that temperature is reached, the motor-operated valve 24 opens the motor-operated valve 25, further lower than the above-mentioned set temperature. There is a contact 72 that opens at a set temperature, and when this contact 72 opens, it is an operating state where liquid injection is unnecessary. Reference numeral 73 denotes a fifth auxiliary relay (R
5), the compressor protection thermo 65, the reverse phase prevention relay 52,
Thermal relay 66 and high / low pressure switch 34H, 3
As long as the 4L does not operate, it is continuously energized and keeps closing the contact 73a that operates the relay.

Reference numeral 74 is a sixth auxiliary relay (R6), which is arranged in parallel with the compressor magnetic contactor 45, is commonly connected to the contact 70 working in the above-mentioned overheat protection thermometer, and is opened when the relay operates. The contact 74a is connected to the fifth auxiliary relay 7
The third contact 73a is connected in series.

Reference numeral 75 is a fourth auxiliary relay (R4), which is connected to the control lines 55a and 55b via the contacts 74a and 73a.
Is connected in between. Therefore, when the fifth auxiliary relay 73 is alive and the sixth auxiliary relay 74 is cut off, in other words, the discharge gas temperature rises to 130 ° C., the discharge gas overheated thermostat operates, and the contact 70 is cut off, so that the compressor 1 When it stops, the magnet operates. Then, once the excitation operation is performed, the self-holding contact 75a self-holds, and at the time of the excitation, the first contact 75b that switches from closed to open and the second contact that switches from open to closed.
It has a contact 75c.

Further, the fan controller 48 has a contact 75d for inputting a control signal, and when the contact 75d is closed, the rotation of the drive motor 10M is controlled to rotate at full speed. Then, the first capacity control valve (V
1) 31 is normally operating via the low pressure pressure control switch 40L for capacity control, a normal refrigerant flow rate is supplied, and the compressor 1 is operated at normal capacity (100%).

On the other hand, low pressure pressure switch 40L for capacity control
The second capacity control valve (V2) 32, which is also connected to the switching side and the contact point 75c, is operated by the discharge gas overheat thermostat, the compressor 1 is stopped, and the discharge gas temperature decreases (for example, 90
C.) and then returns to operation again. At this time, the refrigerant is made to flow in a smaller amount than the normal state, for example, 60%, and the compressor 1 is operated with reduced capacity.

Reference numeral 80 denotes a defrosting control panel, 81 is an operation switch, and the defrosting control panel 81 is provided with a defrosting timer 82, and the timer 82 periodically switches between the cooling side and the defrosting side. It has a timer switch 83 to be operated. The cooling side circuit has a first solenoid valve (SV) 8 that opens when energized.
And the third solenoid valve (SV) 13 are connected in parallel.
On the other hand, a second solenoid valve (SV) 22 and a fourth solenoid valve (SV) 17, which open when energized, are connected in parallel to the circuit on the defrosting side.

When the selection switch 83 is on the cooling side, the cooling operation lamp (WL) 85 is turned on via the pump down stop switch 84. A liquid pipe solenoid valve 86 and a temperature controller 87 are connected in series to the pump down stop switch 84.

88 is an electromagnetic contactor for the evaporator fan motor,
A defrosting completion detection thermostat 89 detects the outer surface temperature of the evaporator 15 and switches when the temperature rise at the end of the defrosting period is detected, deactivating the electromagnetic contactor 88 for the evaporator fan motor and switching it. A return signal for restarting the cooling operation is input to the defrost timer 82 via the side terminal.

90 is a defrosting lamp (G
L), 91 are electromagnetic contactors for defrosting connected in parallel with the defrosting lamp 90, 92 is a box heater (BH), 93 is a drain pipe heater (DPH), which is a drain pan for receiving drain water of the evaporator 15. It is provided. F1, F2
F3, F4, F5 and F6 indicate fuses.

Next, the operation of the refrigerant device of the present invention having the refrigerant circuit and the control circuit having the above-mentioned configurations will be described.

First, during the cooling operation, the operation switch 56,
By turning on the valves 56 and 81, the first solenoid valve 8 and the third solenoid valve 13 are opened to form a refrigeration cycle, while the second solenoid valve 22 and the fourth solenoid valve 17 are closed so that the hot gas circuit does not work.
Further, the electromagnetic contactor 45 for the compressor is excited to drive the compressor 1, and the cooling operation is performed.

Further, the first electric valve 24 for injection control in the liquid injection circuit 3 is opened, liquid refrigerant is injected from the receiver tank 12 through the first and second capillary tubes 26, 27, and the compressor 1 Is subject to cooling.

However, when the liquid injection is insufficient and the temperature of the gas discharged from the compressor 1 rises to 130 ° C., the discharge overheat thermostat works to disconnect the contact 70 and stop the compressor 1.

When the discharge gas temperature is lowered by stopping the compressor 1 and reaches, for example, 90 ° C., the discharge gas overheat thermostat is restored and the contact 70 is closed again, so that the compressor 1 is restarted. Then, at this time, the fourth auxiliary relay 75 is excited and the contact 7
5d enters, and the fan controller 48 drives and controls the drive motor 10M so that the condenser cooling fan 10 rotates at full speed. When the cooling fan 10 operates at full speed, the condensation pressure decreases.

Further, the contact 75b is cut off and the contact 75c is turned on in the fourth auxiliary relay 75, whereby the second capacity control valve 32
Opens. When this valve 32 opens, the high pressure applied to the first capacity control valve 31 escapes, the high pressure port 5a of the compressor becomes low pressure, the internal bypass circuit opens, and the refrigerant flow rate decreases (60% flow rate). ) State, that is, the cooling operation is performed with the cooling capacity reduced.

Such a (1) condenser cooling fan 1
0 is set to full speed rotation. Further, (2) by performing the capacity control operation in which the refrigerant circulation amount is decreased, the condensing pressure can be significantly reduced, the discharge gas temperature is prevented from being overheated, and the compressor 1 is cooled by liquid injection. Even if it cannot be operated, the operation can be continued without damage, and damage to the cooling material can be prevented.

Next, the operation of defrosting with hot gas will be described. At the defrosting time, the timer switch 83 is switched to the defrosting side. Then, the second solenoid valve 22 and the fourth solenoid valve 17 are opened, and the high-temperature refrigerant gas (hot gas) discharged from the compressor 1 flows through the hot gas circuit 21, bypasses the condenser 9 and directly to the evaporator 15. Start defrosting.

First, the liquid refrigerant in the receiver tank 12 flows into the compressor 1 by the liquid injection circuit 3 and is entrusted to the cooling action. However, when the defrosting operation continues, the liquid refrigerant in the receiver tank 12 is depleted and the liquid injection is performed. Is no longer possible, the discharge gas temperature rises, and 130 ° C
When it exceeds the value, the discharge gas superheat thermostat works, the contact 70 is broken, and the compressor 1 is stopped.

When the discharge gas temperature drops to 90 ° C., the discharge gas overheat thermostat is restored and the compressor 1 is restarted. In this case, when the discharged gas superheated thermostat returns, the fourth auxiliary relay 75 is excited as in the cooling operation, and the contact cooling 75d causes the drive motor 10M of the condenser cooling fan 10 to rotate at full speed.

Further, the contact 75b is opened and the contact 75c is closed, and the second capacity control valve 32 is opened, whereby the high pressure applied to the first capacity control valve 31 escapes and the compressor 1 of the compressor 1 is released. The high pressure port 5a becomes low pressure, the internal bypass circuit is opened, the refrigerant circulation becomes 60% capacity, the refrigerant circulation amount is reduced, and the defrosting operation with the reduced capacity is continued, so that no frost remains.

[0065]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the compressor is cooled by the liquid injection to operate, and the refrigerating apparatus is provided with the protection device for stopping the operation when the discharge gas temperature rises and the compressor becomes abnormally high temperature. In the system, when the protective device is activated and returns to operation again, the cooling fan of the condenser is controlled to full speed operation to significantly reduce the condensing pressure, and the refrigerant is bypassed to the load and partially returned to the compressor. By controlling the amount of circulation, the compressor was operated with reduced capacity.

As a result, even if the cooling action by the liquid injection is insufficient, the discharge gas temperature of the compressor is prevented from being overheated, and the operation is continued without damaging the compressor to minimize the damage of the cooling material. Can be limited.

[Brief description of drawings]

FIG. 1 is a Mollier diagram showing a refrigeration cycle.

FIG. 2 is a refrigerant circuit diagram of the refrigerating apparatus according to the present invention.

FIG. 3 is a control circuit diagram of the refrigerating apparatus according to the present invention.

[Explanation of symbols]

 1 Compressor 3 Liquid Injection Circuit 9 Condenser 10 Condenser Cooling Fan 10M Drive Motor 28 Capacity Control System 31 First Capacity Control Valve 32 Second Capacity Control Valve

Claims (3)

[Claims] 1. A liquid injection circuit provided in a refrigeration cycle comprising at least a compressor, a condenser, a condenser cooling fan, and an evaporator decompression device to inject liquid refrigerant into the compressor to cool the compressor. A refrigerating apparatus configured to temporarily stop the compressor with a protection device while the temperature of the compressor exceeds a predetermined temperature; a motor that drives the condenser cooling fan; And a fan controller for rotating the motor for driving the condenser cooling fan at full speed when the temperature of the compressor is lowered and the operation of the compressor is restored. apparatus. 2. A liquid injection circuit provided in a refrigeration cycle including at least a compressor, a condenser, a condenser cooling fan, and an evaporator decompression device to inject a liquid refrigerant into the compressor to cool the compressor. While the temperature of the compressor exceeds a predetermined temperature, in a refrigeration device configured to temporarily stop the compressor with a protection device, a part of the high-pressure gas refrigerant discharged from the compressor is bypassed by the evaporator. A capacity control path for returning to the low pressure side of the compressor, an electrically operated valve provided in the capacity control path, and a temperature of the compressor is lowered after the protection device is activated to temporarily stop the compressor. And a valve opening / closing control device that opens the motor-operated valve when the operation is restored. 3. A liquid injection circuit provided in a refrigeration cycle including at least a compressor, a condenser, a condenser cooling fan, and an evaporator pressure reducing device to inject liquid refrigerant into the compressor to cool the compressor. In a refrigeration system configured to temporarily stop the compressor with a protective device while the temperature of the compressor exceeds a predetermined temperature, a motor for driving the condenser cooling fan, and a high-pressure gas refrigerant discharged from the compressor. A part of the capacity control path that bypasses the evaporator and returns to the low pressure side of the compressor, an electric valve provided in the capacity control path, and the protection device operates to temporarily stop the compressor. After that, when the temperature of the compressor is lowered and the operation of the compressor is restored, the motor for driving the condenser cooling fan is rotated at full speed and the motor operated valve is opened. Refrigerating apparatus characterized by comprising a driving control device.