JPH089588Y2 - Cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an improved configuration of a cooling device that defrosts a cooler with a high temperature refrigerant discharged from a compressor, so-called hot gas.

(B) Conventional Technology In the conventional cooling device of this type, defrosting of the cooler is performed by an electric heater or by flowing so-called hot gas discharged from the compressor into the cooler for heating.
In defrosting with hot gas, a plurality of coolers are further provided and placed as in Japanese Patent Publication No. 42-11638, which precedes the present application, to depressurize the refrigerant condensed therein during hot gas defrosting of the first cooler. It is made to flow into the second cooler and evaporated.

(C) Problems to be Solved by the Invention According to the configuration of the invention, although the second evaporator cools the defrosting of the first evaporator, there is an advantage that the temperature rise in the refrigerator can be suppressed. , The temperature of the first evaporator is 0 ℃ ~
Since the temperature is 10 ° C, which is considerably lower than that of a normal condenser (about + 30 ° C), the condensing pressure becomes lower, and the suction pressure of the compressor also lowers, so the low pressure switch of the compressor operates and the compressor stops. There was a problem.

(D) Means for Solving the Problems The present invention installs a main cooler in the ventilation passage, and when the main cooler is defrosted, the high temperature refrigerant discharged from the compressor is introduced to perform defrosting. In the cooling device, an auxiliary cooler, a flow path switching device that depressurizes the refrigerant from the main cooler when defrosting the main cooler and flows it to the auxiliary cooler, and a discharge side of the compressor when defrosting the main cooler. A flow control device that communicates with the suction side via a thin tube is provided.

In the present invention, the auxiliary cooler further comprises first and second auxiliary coolers, and both auxiliary coolers are arranged on the windward side and leeward side of the main cooler in the ventilation passage.

(E) Operation According to the present invention, since the main cooler is heated by the inflow of the high-temperature refrigerant from the compressor, the frost adhering to the main cooler is melted. Even during the defrosting of the main cooler, a part of the refrigerant discharged from the compressor is returned to the suction side, so that the pressure on the suction side of the compressor does not decrease and is compensated.

Furthermore, since the cooling effect is exerted by the auxiliary cooler during defrosting of the main cooler, the temperature of the cooling space can be maintained.

In particular, the circulating cold air dehumidified by the first auxiliary cooler is
Although the temperature once rises in the process of passing through the main cooler during defrosting, it is then cooled again by the second auxiliary cooler and blown into the cooling space.

(F) Example Next, an example will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of the present invention, and FIG. 2 is a vertical sectional view of an open showcase 1 as an embodiment.

In FIG. 2, the open showcase 1 is composed of a heat insulating wall 2 formed with an opening 3 for taking out a product on the front surface, and a first partition plate 4 is formed at an appropriate distance from the inner wall of the heat insulating wall 2. The bottom plate 5 and the second partition plate 6 are arranged, and the ventilation path 7
And a protective passage 8 surrounding the same. Also,
A first air outlet 9 and a second air outlet 10 are formed at the upper end of the opening 3, and a suction port 11 is formed at the lower end facing the first air outlet 9.

In the ventilation passage 7, a main cooler 12 is vertically installed in the lower part of the back surface, and a blower 13 is installed in the bottom part. Similarly, in the ventilation passage 7, the first side is provided on the suction port 11 side of the blower 13.
The auxiliary cooler 14 is installed, and the second auxiliary cooler 15 is arranged above the main cooler 12.

The blower 13 is constantly operated so that air is circulated from the suction port 11 into the ventilation passage 7 and blown out from the first blowout port 9 into the storage chamber 16, and a part of the air from the suction port 11 is protected inside the protection passage 8. It is blown out from the 2nd blow-off mouth 10 through it, and constitutes an air curtain in the opening 3 part.

Next, in the refrigerant circuit diagram of FIG. 1, the discharge side pipe 20D of the compressor 20 is branched, and one of them reaches the solenoid valve 24 via the condenser 21, the receiver tank 22 and the dryer 23. Discharge side piping 20
The other of D is connected to the downstream side of the solenoid valve 24 via the condensing pressure control valve (CPR) 25 and the solenoid valve 26.

The pipe exiting the solenoid valve 24 reaches the main cooler 12 via the solenoid valve 27 and the expansion valve 28. A series circuit of the solenoid valve 29 and the check valve 30 is connected in parallel to the series circuit of the solenoid valve 27 and the expansion valve 28.

The piping exiting the main cooler 12 passes through a solenoid valve 31, a suction pressure regulating valve (SPR) 32, an accumulator 33, and a compressor 20.
Is connected to the suction side pipe 20S.

The solenoid valve 31 is further connected in parallel with a series circuit of a solenoid valve 34, an expansion valve 35, a first auxiliary cooler 14 and a second auxiliary cooler 15.

Also, the condensation pressure control valve (C
The upstream side of the PR) 25 and the upstream side of the suction pressure control valve (SPR) 32 are connected by a thin tube 36 having a small tube diameter.
A solenoid valve 37 is provided at 36.

Next, the operation will be described. The control device (not shown) opens the solenoid valves 24, 27 and 31 during the normal cooling operation, and the solenoid valves 26, 2
9, 34 and 37 are closed. The high-temperature and high-humidity gas refrigerant discharged from the compressor 20 flows into the condenser 21 as shown by the thick line in FIG. 1 to radiate heat, and is condensed and liquefied. The condensing pressure at this time is 16 kg / cm ^{2 at} an ambient temperature of 30 ° C. The refrigerant discharged from the condenser 21 passes through the receiver tank 22, the dryer 23, the electromagnetic valves 24 and 27, is decompressed by the expansion valve 28, flows into the main cooler 12, and is evaporated. Cold air cooled by the main cooler 12 cooled by this evaporation is discharged from the air outlets 9 and 10 and stored in the storage chamber 16.
Is cooled to 0 ° C to -2 ° C.

The refrigerant discharged from the main cooler 12 passes through a solenoid valve 31, a suction pressure adjusting valve (SPR) 32, and an accumulator 33, and a suction side pipe 2
It is sucked into the compressor 20 from 0S.

Next, when such a cooling operation is continued for a predetermined time,
Since frost grows on the main cooler 12, the controller starts defrosting the main cooler 12. In this case, solenoid valves 24, 27 and 31
Closed and solenoid valves 26, 29, 34 and 37 open. Therefore, the high-temperature and high-pressure refrigerant discharged from the compressor 20 does not pass through the condenser 21 but through the condensation pressure regulating valve (CPR) 25, the solenoid valves 26 and 29, and the check valve 30 as shown by the thick line in FIG. It directly flows into the main cooler 12. Here, the condensing pressure control valve (CPR) 25 operates to close the flow path when the condensing pressure of the main cooler 12 rises and to open it when the condensing pressure falls.

The main cooler 12 is heated by the inflow of this high-temperature refrigerant,
Frost is melted and removed. On the other hand, the gas refrigerant radiates heat and condenses. The condensed refrigerant exits the main cooler 12 and the solenoid valve 34
Through the expansion valve 35 and is depressurized by the expansion valve 35 to flow into the first auxiliary cooler 14 where it evaporates to cool it, and then also flows into the second auxiliary cooler 15 to evaporate and cool. .

As a result, the air sucked from the suction port 11 by the blower 13 first passes through the first auxiliary cooler 14, where it is cooled and dehumidified, and then passes through the main cooler 12. Here, since the main cooler 12 is being defrosted, the temperature of the cool air passing therethrough rises, but the second auxiliary cooler continues.
Since it is cooled again in the process of passing through 15 and is blown into the storage chamber 9, the temperature rise in the storage chamber 16 does not occur, and the inside of the storage chamber 16 can be cooled even during defrosting of the main cooler 12.

Here, since the temperature of the main cooler 12 during defrosting is 0 ° C. to + 10 ° C., the condensing pressure drops to about 7 kg / cm ² , so the suction pressure of the compressor 20 also drops, and the compressor 20 The low pressure switch built into 20 operates and compressor 20 stops.

However, in this case, since the solenoid valve 37 is open,
The discharge side and the suction side of the compressor 20 are connected by 36.
Since this thin tube 36 directly joins about 10% of the high-temperature high-pressure gas refrigerant discharged from the compressor 20 to the suction side, the suction pressure of the compressor 20 rises and is compensated, so that the main cooler 12 is defrosted. The compressor 20 never stops.

The refrigerant that has joined upstream of the suction pressure control valve (SPR) 32 is
It is sucked into the compressor 20 through the suction pressure control valve (SPR) 32 and the accumulator 33.

In addition, although the present invention is applied to the open showcase in the embodiment, the present invention is not limited to this and is also effective in a normal refrigerator, a freezer or the like.

(G) Effect of the Invention According to the present invention, the main cooler is heated by the inflow of the high-temperature refrigerant from the compressor, so that the main cooler is defrosted. Even during the defrosting of the main cooler, a part of the refrigerant discharged from the compressor is returned to the suction side, so that the pressure on the suction side of the compressor is compensated without lowering, so that the defrosting of the main cooler is prevented. Achieved smoothly.

Furthermore, since the cooling effect is exerted by the auxiliary cooler during defrosting of the main cooler, the temperature of the cooling space can be maintained.

Particularly, if the auxiliary cooler is composed of the first and second auxiliary coolers and is arranged on the upstream side and the downstream side of the main cooler in the ventilation passage, the circulating cold air is dehumidified by the first auxiliary cooler. After being defrosted, it reaches the main cooler during defrosting, so that frost formation on the main cooler during defrosting can be prevented and the defrosting time can be shortened. Further, the temperature of the cool air once rises in the process of passing through the main cooler, but thereafter it is cooled again by the second auxiliary cooler and blown into the cooling space, so that the temperature of the cooling space does not rise. .

[Brief description of drawings]

Each drawing shows an embodiment of the present invention, FIG. 1 is a refrigerant circuit diagram for explaining refrigerant circulation during a cooling operation, FIG. 2 is a vertical sectional view of an open showcase, and FIG. 3 is defrosting of a main cooler. It is a refrigerant circuit diagram explaining refrigerant circulation at the time. 7 ... Ventilation path, 12 ... Main cooler, 14, 15 ... 1st, 2nd
Auxiliary cooler, 24, 26, 27, 29, 31, 34, 37 ... Solenoid valve, 35 ... Expansion valve, 36 ... Thin tube.

Claims (2)

[Scope of utility model registration request] 1. A cooling device in which a main cooler is installed in a ventilation passage, and at the time of defrosting the main cooler, a high-temperature refrigerant discharged from a compressor is introduced to defrost the auxiliary cooler. A flow path switching unit that decompresses the refrigerant from the main cooler to flow to the auxiliary cooler when defrosting the main cooler, and a discharge side and a suction side of the compressor when defrosting the main cooler. A cooling device comprising a flow control means that communicates with each other via a. 2. The auxiliary cooler is composed of first and second auxiliary coolers, and both auxiliary coolers are arranged on the windward side and leeward side of the main cooler in the ventilation passage. The cooling device according to item 1.