JPS583013Y2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a so-called reverse cycle defrost type refrigeration system in which the evaporator is defrosted by circulating refrigerant in the opposite direction.

Regarding refrigeration equipment, there is a known method in which when the condensation pressure in the condenser drops excessively, the high-temperature gas refrigerant is bypassed through a bypass pipe line installed in parallel to the condenser. When a reverse cycle defrost system is adopted for a motor, the liquid refrigerant flows into the compressor via the bypass pipe at the time of the reverse cycle defrost.
A so-called liquid back problem occurs.

This invention was developed with the aim of solving the above-mentioned liquid back-up problem in a refrigeration system that has a condenser bypass line and performs reverse cycle defrost operation. A four-way switching valve that switches between reverse cycle defrosting operation, a condenser, an expansion valve for defrosting operation, and a first
Parallel circuit with check valve, liquid receiver, expansion valve for refrigeration operation and second
A refrigerant circulation circuit is provided in which a parallel circuit with a check valve and an evaporator are sequentially connected to supply high-temperature gas refrigerant to the evaporator by switching operation of the four-way switching valve during defrosting operation of the evaporator. a high-pressure control valve configured to open a bypass pipe for hot gas bypass when the refrigerant condensation pressure decreases when the refrigerant condensation pressure is pressed in the condenser; While connected in series, one end of the bypass pipe is connected to the inlet side of the condenser during refrigeration operation, and the other end is connected to the hot gas inlet of the high pressure control valve to prevent a drop in condensation pressure during refrigeration operation. In addition to preventing this, the bypass pipe is further provided with a valve that acts to prevent the flow of refrigerant during reverse cycle defrosting operation.

Next, the refrigeration system of the present invention will be explained with reference to the embodiment shown in the attached drawings. The refrigeration system shown in FIG. , expansion valve 15 for defrosting operation and first check valve 1
4, the liquid receiver 20, the parallel circuit of the expansion valve 17 for refrigeration operation and the second check valve 16, and the evaporator 13 are connected in sequence, and when the evaporator 13 is in defrosting operation, the Road switching valve 1
A refrigerant circulation circuit is constructed that can supply high-temperature gas refrigerant (hot gas) to the evaporator 13 by switching operation 1.

Further, a bypass pipe line 2 for bypassing hot gas when the condensation pressure of the refrigerant in the condenser 12 decreases is connected to the condenser 1.
A high-pressure control valve 1 for controlling the opening and closing of the bypass line 2 is connected in parallel to the defrosting operation expansion valve 15 and in series with the first check valve 14.

One end of the bypass pipe 2 is connected to the inlet side of the condenser 12 during refrigeration operation, and the other end is connected to the hot gas inlet of the high pressure control valve 1 (described later).

In FIG. 1, a solid line arrow X indicates a refrigerant circulation path during normal refrigeration operation, and a broken line arrow Yl-j indicates a refrigerant circulation path during reverse cycle defrost operation.

That is, in the embodiment shown in FIG. 1, during refrigeration operation, after the refrigerant is discharged from the compressor 10, the refrigerant is passed through the four-way selector valve 11 and the condenser 1.
2. Returns to the compressor 10 via the high pressure control valve 1, the bypass circuit 25 with the first check valve 14, the liquid receiver 20, the expansion valve 17 for refrigeration operation, the evaporator 13, and the four-way switching valve 11. .

In this case, when the condensation pressure of the refrigerant in the condenser 12 becomes lower than a predetermined value (for example, 13 kg/crlL), the high pressure control valve 1 causes the refrigerant to flow through the bypass pipe 2 as shown by the chain arrow X'. It is designed to flow through

In the embodiment shown in FIG. 1, a solenoid valve 3 is inserted into the bypass line 2, and this solenoid valve 3 is maintained in an open state during refrigeration operation.

FIG. 2 shows an example of an electric circuit for controlling the opening and closing of the solenoid valve 3.

In FIG. 2, reference numeral 21 denotes the electromagnetic coil of the electromagnetic valve 3, and 22
(/'i Defrost detection contact that turns ON during defrost operation and turns OFF when defrost operation ends; 23 is a relay that is energized or de-energized depending on whether the defrost detection contact 22 is ON or OFF; 24 is a normally closed contact of relay 23; When the contact 24 is ON (ie, during refrigeration operation), the solenoid valve opens, and when the contact 24 is OFF (ie, during defrost i rotation), the solenoid valve 3 closes.

FIG. 3 shows a preferred structural example of the high pressure control valve 1 that can be used in the refrigeration system shown in FIG.

This high pressure control valve 1 has three ports) Pa and Pb.

A valve body 32 is housed in a valve housing 31 having a valve body Pc2, and the valve body 32 selectively opens and closes two valve seats 33 and 34.

Note that the valve body 32 is urged toward one valve seat 33 by a spring 35.

In the refrigeration system shown in Fig. 1, the port of the high pressure control valve 1 is
(hot gas inlet) is connected to the bypass pipe 2 side, port Pb is connected to the outlet side of the condenser 12, and port Pe is connected to the receiver side 13 side.

During normal refrigeration operation, when the condensation pressure of the refrigerant exceeds a predetermined value, the high pressure control valve 1
It acts to close the 3 side and open the valve seat 34 side.

Therefore, the liquid refrigerant condensed in the condenser 12 is
(Po) can flow toward Pe.

On the other hand, when the condensation pressure of the refrigerant drops below a predetermined value, the valve body 32 is displaced toward the valve seat 34, ports Pa and Pb communicate with each other, and the high temperature gas refrigerant flows as shown by the chain arrow X'. It bypasses the condenser 12 (the solenoid valve 3 is in the open state) and acts to flow to the receiver 13 side, thereby preventing a drop in pressure in the condenser 12, thereby reducing the condensing pressure. This prevents the phenomenon of liquid backing up when the water drops (which often occurs especially in winter).

Next, the refrigerant circulation path during reverse cycle defrost operation in the refrigeration system shown in FIG. .

Therefore, the high pressure control valve 1 connected to the outlet side of the condenser 12
The port Pb is in a low pressure state during the reverse cycle defrost operation, and accordingly, the valve body 32 is seated on the valve seat 34 side.

Therefore, the liquid refrigerant accumulated between the high pressure control valve 1 Pc and the check valve 14 flows back into the bypass pipe 2 via the port Pa.

Furthermore, if the sealing performance of the valve body 32 of the high-pressure control valve 1 is poor, liquid refrigerant may leak from port (Pb) to port Pa.

However, in the embodiment shown in FIG. 1, the bypass line 2 is provided with a solenoid valve 3, and the solenoid valve 3 is closed during the reverse cycle defrost operation, so that the leakage to the port Pa side occurs. A so-called liquid back phenomenon in which the liquid refrigerant flows back to the compressor 10 via the bypass line 2 does not occur.

In the embodiment shown in Fig. 1, a solenoid valve 3 is used in the bypass pipe 2, but in other embodiments of the present invention, a check valve (as shown in Fig. 1) is used instead of the solenoid valve 3. (Press the button to allow refrigerant flow only in the direction of arrow X/, and prevent refrigerant flow in the opposite direction.)
You can also use

As is clear from the above description, the refrigeration system of the present invention has a condenser bypass line 2, and has a reverse cycle defrosting system.
Although it is a refrigeration system that performs seven rotations, it also solves the problem of liquid leakage during reverse cycle defrost operation, and has the effect of contributing to the prevention of troubles that can occur with this type of refrigeration system.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant circuit diagram of a refrigeration system according to an embodiment of the present invention, Fig. 2 is a control circuit diagram of the solenoid valve shown in Fig. 1, and Fig. 3 is a vertical sectional view of the high pressure control valve shown in Fig. 1. It is. 1...High pressure control valve, 2...Bypass pipe line, 3...Solenoid valve (or check valve), 10...
... Compressor, 11... Four-way switching valve, 12...
...Condenser, 13...Evaporator.

Claims (1)

[Scope of utility model registration request] Compressor 10, four-way selector valve 11 for switching between refrigeration operation and reverse cycle defrosting operation. Condenser 12, expansion valve 1 for defrosting operation
5 and the first check valve 14, the liquid receiver 20, the parallel circuit of the refrigeration operation expansion valve 17 and the second check valve 16, and the evaporator 13 are connected in sequence. During defrosting operation,
A bypass pipe line constitutes a refrigerant circulation circuit that can supply high-temperature gas refrigerant to the evaporator 13 by switching the four-way switching valve 11, and is used as a hot gas bypass when the condensation pressure of the refrigerant in the condenser 12 decreases. 2, the high pressure control valve 1 which operates to open the first valve is connected in parallel to the defrosting operation expansion valve 15.
While connected in series with the check valve 14, the bypass pipe 2
One end is connected to the inlet side of the condenser 12 during refrigeration operation, and the other end is connected to the hot gas inlet of the high pressure control valve 1 to prevent a decrease in condensing pressure during refrigeration operation, and the bypass pipe 2 is further provided with a valve 3 which is turned on during reverse cycle defrosting operation and acts to prevent the flow of refrigerant.