JPS6230683Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a water-cooled refrigeration system.

Figure 1 shows an example of a conventional refrigeration system.
1 is a compressor, 2 is a water-cooled condenser, 3 is a liquid line solenoid valve, 4 is an expansion valve, 5 is an evaporator, 6 is an accumulator, 7 is a defrosting hot gas line solenoid valve, 8 is a cooling water pipe During refrigeration operation, high-temperature, high-pressure refrigerant gas discharged from the compressor 1 is condensed in the water-cooled condenser 2, becomes liquid refrigerant, passes through the liquid line solenoid valve 3, is throttled by the expansion valve 4, and evaporates in the evaporator 5. It is vaporized and returns to the compressor 1 through the accumulator 6.

Moreover, as a result of repeated refrigeration operations, it adheres to the evaporator 5. In order to melt the frost, the hot gas solenoid valve 7 is opened to supply hot gas to the evaporator 5.

The arrows indicated by solid lines in the figure indicate the flow of refrigerant during freezing operation, and the arrows indicated by broken lines indicate the flow of refrigerant during defrosting operation in which hot gas flows.

In such a refrigeration system, the evaporator 5 is always at 0.
It is often cooled below ℃. Therefore, even when the compressor 1 is stopped, the pressure in the evaporator 5 remains lower than other parts. As a result, the refrigerant in the condenser 2 is in a pressure relationship such that it always flows to the evaporator 5 across the solenoid valves 3 and 7 and the valve (not shown) of the compressor 1.
Under these conditions, if the supply of cooling water from the cooling water pipe 8 is stopped, there may be abnormal damage to the discharge valve and suction valve of the compressor 1, or abnormal leakage may occur from the hot gas solenoid valve 7. If so, the liquid refrigerant in the condenser 2 will boil rapidly and flow into the evaporator 5. At this time, the water remaining in the cooling pipe in the condenser 2 turns into ice, which may sometimes damage the cooling pipe and cause the refrigerant circuit and water circuit to connect, damaging the refrigeration system. Once water has entered the refrigerant circuit, it is very difficult to remove it.

This phenomenon occurs not only due to the damage to the valve mentioned above, but also due to gas leaking from the condenser 2 at an abnormal rate in refrigeration systems that use refrigerants whose boiling point at atmospheric pressure is 0°C or less. there's a possibility that.

However, if there is enough cooling water to cover the amount of cooling generated when the refrigerant evaporates, the water will not freeze, but a large amount of cooling water is required, which poses a problem in terms of energy conservation.

The present invention was proposed in view of the above points, and includes a check valve between a water-cooled condenser and a liquid receiver in a water-cooled refrigeration system to prevent refrigerant from flowing backward from the liquid receiver to the water-cooled condenser. The invention is characterized in that it is also provided with a circuit that communicates the inner space of the liquid receiver with the low pressure side for a predetermined period of time when the compressor is stopped, and its purpose is to prevent damage to the cooling water pipe of the water-cooled condenser due to freezing. The aim is to provide a refrigeration system that can

Since the present invention is configured as described above, when the compressor stops, the internal space of the receiver is connected to the low pressure side and the pressure decreases, so the liquid refrigerant held in the water-cooled condenser is reversed. After passing through the stop valve, the refrigerant moves into the liquid receiver, and only the gas refrigerant is held in the water-cooled condenser. Therefore, even if the supply of cooling water to the water-cooled condenser is stopped, the water in the cooling water pipes does not freeze, and damage to the cooling water pipes can be prevented.

Hereinafter, the present invention will be explained based on illustrated embodiments.

In FIG. 2, 11 is a compressor, 12 is a water-cooled condenser, 13 is a liquid line solenoid valve, 14 is an expansion valve, 1
5 is an evaporator, 16 is an accumulator, 17 is a hot gas line solenoid valve for defrosting, 18 is a cooling water pipe, 19 is a check valve, 20 is a liquid receiver, 21 is a bypass line solenoid valve, and a reverse The stop valve 19 is a liquid receiver 20
The solenoid valve 21 prevents refrigerant from flowing backward from the side to the water-cooled condenser 12 side, and the solenoid valve 21 is provided between the upper part of the liquid receiver 20 and the downstream side of the solenoid valve 17 of the defrosting hot gas line, which is the low pressure side. It is provided in the bypass line connected to the compressor 11, and is opened when the compressor 11 is stopped.
It closes after a predetermined time has elapsed using a timer or the like, and this time is set as appropriate depending on the device.

In the above case, the bypass line is connected between the upper part of the liquid receiver and the hot gas line, but it is connected from the refrigerant circuit between the check valve 19 and the liquid receiver 20 and the downstream side of the expansion valve 14. It can be connected between the refrigerant circuit up to the compressor 11 or equipment.

In the above configuration, during refrigeration operation, the high temperature and high pressure refrigerant gas discharged from the compressor 11 is condensed in the water-cooled condenser 12 and becomes liquid refrigerant through the check valve 19 and accumulated in the liquid receiver 20 as shown by the solid line arrow. . After that, the liquid line passes through a solenoid valve 13, is throttled by an expansion valve 14, is evaporated in an evaporator 15, and is vaporized in an accumulator 16.
and returns to the compressor 11.

On the other hand, during defrost operation, the high-temperature, high-pressure refrigerant gas discharged from the compressor 11 passes through the hot gas line solenoid valve 17 and enters the evaporator 15, as shown by the broken line. Here, the frost is melted and a two-phase flow of low-temperature gas and liquid is created, and the gas and liquid are separated in the accumulator 16 and returned to the compressor 11.

Here, if the cooling water to the water-cooled condenser 12 is stopped when the refrigeration system is stopped, that is, the compressor 11 is stopped, the discharge valve and suction valve of the compressor 11 may be abnormally damaged, and the hot gas line may be damaged. If there is an abnormal leak in the solenoid valve 17, the liquid refrigerant in the water-cooled condenser 12 will rapidly boil and flow into the evaporator 15.
As mentioned above, the water remaining in the cooling water pipes in the water-cooled condenser 12 turns into ice, which could lead to a major accident that could damage the cooling water pipes. Solenoid valve 21
is opened for a certain period of time, and the gas refrigerant accumulated in the upper part of the liquid receiver 20 is bypassed by the solenoid valve 2 as shown by the dashed line.
1 to the evaporator, the pressure inside the liquid receiver 20 decreases, and the liquid refrigerant held in the water-cooled condenser 12 moves to the liquid receiver 20 through the check valve 19. do. Therefore, water-cooled condenser 1
Only gas refrigerant is held in the water-cooled condenser 12, even if there is abnormal damage to the discharge valve or suction valve of the compressor 11, or abnormal leakage to the hot gas line solenoid valve 17. Since there is no liquid refrigerant that evaporates, there is no risk of accidents such as water freezing and damage in the cooling water pipes.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit diagram showing a conventional one, and FIG. 2 is a refrigerant circuit diagram showing an embodiment of the present invention. 11...Compressor, 12...Water-cooled condenser, 13...
... Liquid line solenoid valve, 14 ... Expansion valve, 15 ... Evaporator, 16 ... Accumulator, 17 ... Hot gas line solenoid valve, 18 ... Cooling water piping, 19 ...
...Check valve, 20...Liquid receiver, 21...Bypass line solenoid valve.

Claims (1)

[Scope of utility model registration request] In a water-cooled refrigeration system, a check valve is provided between the water-cooled condenser and the liquid receiver to prevent refrigerant backflow from the liquid receiver to the water-cooled condenser, and when the compressor is stopped,
A refrigeration system comprising a circuit that communicates the inner space of the liquid receiver with a low pressure side for a predetermined period of time.