JPS6054578B2 - Defrosting device for refrigeration cycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a defrosting device for a refrigeration cycle, and involves defrosting one evaporator using hot gas while operating the other evaporator in a cooling operation. The purpose of this is to introduce part of the gas into the low pressure side to increase the pressure on the low pressure side and also to increase the high pressure side to prevent a decrease in defrosting and cooling ability.

The present invention will be explained below based on the drawings. 1 is a compressor;
2 is a condenser, 3 is a first solenoid valve, 4 is a first pressure reducing valve provided in parallel to the first solenoid valve 3, 5 is a liquid receiver, 6 and 7 are expansion valves, and 8 and 9 are the expansion valves. Second and third solenoid valves are provided in parallel with the valves 6 and 7, 10 and 11 are evaporators, 12 and 13 are fourth and fifth solenoid valves, and 14 and 15 are the fourth and fifth solenoid valves 1.
2 and 13 are provided in parallel with second and third pressure reducing valves, 16 is an accumulator, and 17 is a hot gas bypass pipe provided between the compressor 1 and condenser 2. Evaporators 10, 11 and fourth and fifth solenoid valves 12
, 13 are connected with branch pipes 20 and 21 provided with hot gas solenoid valves 18 and 19, respectively, to constitute a refrigeration cycle.

Thus, 22 connects the hot gas bypass pipe 17 and the fourth
This is a conduit connected to a low pressure side pipe 23 between the fifth solenoid valves 12, 13 and the accumulator 16, with a sixth solenoid valve 24 operated by high pressure side pressure.

25 is a high-pressure pressure detector that operates the sixth electromagnetic valve 24 provided in the condenser 2.

Figure 2 shows the operating circuit during defrosting operation of the refrigeration cycle. 26 is an alternating current power supply, and in series with the alternating current power supply are a parallel circuit of a compressor electromagnetic contactor normally open contact 27, an auxiliary relay normally closed contact 28 and a high pressure pressure detector contact 29, and a sixth electromagnetic valve electromagnetic contact. A series circuit with the device 30 is connected.

31 is a defrost timer connected in parallel to the series circuit.

A series circuit of the defrost timer normally open contact 32 and the auxiliary relay 33 is connected in parallel to the defrost timer 31. In the defrosting device for the refrigeration cycle configured in this way,
When the evaporator 10 enters defrosting operation by the defrosting timer 31 during defrosting, the fourth solenoid valve 12 is closed and the hot gas solenoid valve 1 is closed.
8 is opened and a part of the high temperature, high pressure gas refrigerant discharged from the compressor 1 is passed through the hot gas bypass pipe 17 as hot gas.
The liquid flows through the branch pipe 20, defrosts the evaporator 10, and flows into the liquid receiver 5 through the second electromagnetic valve 8. The remaining part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is liquefied in the condenser 2, and since the first solenoid valve 3 is closed, the pressure is reduced to a level slightly lower than the hot gas pressure in the pressure reducing valve 4, and the remaining part is received. It flows into the liquid container 5, prevents it from flowing back into the evaporator 10 which is being defrosted, and flows into the evaporator 11 to form a cooling cycle. Thereafter, the evaporators 11 are defrosted one after another in the same manner, and after the defrosting is completed, cooling operation is started for all the evaporators 11. During defrosting, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is diverted to the hot gas bypass pipe 17, so the pressure on the high-pressure side decreases, reducing the defrosting capacity, cooling capacity, etc. The high-pressure pressure detector 25 installed in the pipe 2 opens the sixth solenoid valve 24 and a part of the hot gas is transferred to the pipe 2.
2 to the low-pressure side to increase the low-pressure pressure and increase the discharge output of the compressor 1, improving the defrosting ability and cooling ability! ing.

When the discharge output rises to abnormal pressure, the sixth solenoid valve 24
The pressure is reduced from one of the branch pipes 20 and 21 communicating with the hot gas bypass pipe 17 to the low pressure side of the second and third pressure reducing valves 14 and 15 to prevent the occurrence of abnormally high pressure. There is.

Further, the operation of the operating circuit shown in FIG. 2 will be explained below. When the defrost timer 31 is activated and the defrost operation begins, the defrost timer normally open contact 32 is closed and the auxiliary relay 33 is energized.

By energizing the auxiliary relay 33, the normally closed contact 28 of the auxiliary relay that self-holds the electromagnetic contactor 30 for the sixth electromagnetic valve is opened, and by turning on and off the high pressure detection contact 29, the electromagnetic contactor for the sixth electromagnetic valve is turned on and off. Turn the operation on and off. As described above, the present invention provides a compressor, a condenser, a liquid receiver, a plurality of evaporators connected in parallel, a pressure reducing device individually connected to the inlet side of each evaporator, and each of these pressure reducing devices. a solenoid valve connected in parallel to the evaporator, a solenoid valve connected individually to the outlet side of each evaporator, and a solenoid valve connected from the discharge side of the compressor to each between the evaporator and the solenoid valve on the outlet side of the evaporator. The hot gas bypass pipe is equipped with a solenoid valve installed in each pipe leading to each evaporator in this bypass pipe, and when defrosting the evaporator, a portion of the hot gas discharged from the compressor is removed. is guided through a hot gas bypass pipe and an evaporator for defrosting to a liquid receiver, while the remaining hot gas discharged from the compressor is guided to the liquid receiver via a condenser, and from this liquid receiver during cooling operation. In a refrigeration cycle configured to return refrigerant to the compressor via the evaporator, a conduit is provided that connects the hot gas bypass pipe and the suction pipe of the compressor, and this conduit is connected to the compressor and the pressure reducing device. Since it is equipped with a solenoid valve that opens when the pressure is lower than the set pressure and closes when the pressure is higher than the set pressure, if the high-pressure side pressure of the refrigeration cycle decreases due to the diversion of the discharged gas refrigerant during defrosting, A portion of the hot gas flowing through the hot gas bypass pipe can be guided to the low-pressure side pipe through the conduit, increasing the temperature and pressure of the refrigerant gas on the low-pressure side of the refrigeration cycle, thereby increasing the temperature and pressure of the discharge gas of the compressor. It is possible to increase the defrosting capacity of each evaporator, shorten the defrosting time, and improve the cooling capacity of the refrigeration cycle.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram showing one embodiment of the present invention;
The figure is an operating circuit diagram. 1...Compressor, 2...Condenser, 6,7
......expansion valve, 10,11...evaporator,
17... Hot gas bypass pipe, 18, 19.
...Hot gas solenoid valve, 22 ... Conduit, 2
3...Low pressure side piping, 24...Solenoid valve.

Claims (1)

[Claims] 1 Compressor, condenser, liquid receiver, multiple evaporators connected in parallel, pressure reducing devices individually connected to the inlet side of each evaporator, and electromagnetic devices connected in parallel to each of these pressure reducing devices valves, solenoid valves individually connected to the outlet side of each evaporator, hot gas bypass pipes connected respectively from the discharge side of the compressor between the evaporator and the solenoid valve on the outlet side of the evaporator; This bypass pipe is equipped with an electromagnetic valve installed in each pipe leading to each evaporator, and when defrosting the evaporator, a portion of the hot gas discharged from the compressor is transferred to the hot gas bypass pipe and defrosted. The remaining hot gas discharged from the compressor is guided to the liquid receiver via the condenser, and from this liquid receiver to the compressor via the evaporator in cooling operation. In a refrigeration cycle configured to return refrigerant to the compressor, a conduit is provided that connects the hot gas bypass pipe and the suction pipe of the compressor, and when the pressure between the compressor and the pressure reducing device is lower than the set pressure. A defrosting device for a refrigeration cycle characterized by being provided with a solenoid valve that opens when the temperature is high and closes when the temperature is high.