JPH0518026B2 - - Google Patents

Description

[Detailed Description of the Invention] [Prior Art] In a refrigeration system that has a mechanism that performs defrosting operation by hot gas defrost, the gas sucked into the compressor from the cooler reaches a high temperature at the end of defrosting. . Therefore, the temperature of the discharged gas increases abnormally.

Further, in a conventional device in which only a suction pressure regulating valve is provided on the suction side of the compressor, although overload due to suction of high-pressure gas into the compressor can be prevented, it is not possible to lower the temperature of the discharged gas.

[Object of the present invention] The present invention provides a refrigeration system with a mechanism for performing defrosting operation using hot gas defrost, in which the gas side of the condenser is connected to a relief protection container having a leak valve in the middle, and the compressor is The temperature on the discharge side or the pressure inside the condenser is detected, and when these temperatures and pressures exceed a predetermined value, the leak valve is opened and the high-temperature, high-pressure gas is released from the relief pipe to the protective container, thereby preventing excessive refrigerant gas. The purpose is to prevent temperature and pressure increases.

[Structure of the device of the present invention] The refrigerant discharge temperature control device for a refrigerator according to the present invention is used in a refrigerator in which refrigerant from a compressor is sucked into the compressor again through a condenser and a cooling coil of a cooler. A defrost pipe that branches from the discharge side of the machine and has a defrost valve that is closed during refrigeration operation but opens during defrosting operation is connected to the inlet side of the cooling coil of the cooler, and the outlet of the cooling coil is connected to the compressor. The suction pipe is provided with a suction pressure regulating valve, and the gas side of the condenser is connected to a protective container through a relief pipe having a leak valve that is opened and closed depending on the temperature of the refrigerant on the discharge side of the compressor or the pressure inside the condenser. This protective container is connected to the suction side of the compressor through a connecting pipe, and the connecting pipe is provided with a throttling device whose pressure is adjusted by a pressure sensing section disposed on the outlet side.

[Embodiment of the present invention] Fig. 1 shows a first embodiment of the present invention. In the figure, reference numeral 1 is a compressor, the discharge side of which is connected to a condenser 3 through a discharge pipe 2. The liquid side of No. 3 is connected to the inlet of a cooling coil 7 in a cooler 6 by a liquid sending pipe 5 having an expansion valve 4, and the inlet of the cooling coil 7 is branched from the discharge pipe 2, and is opened during defrosting. A defrost pipe 9 equipped with a defrost valve 8 (closed during refrigeration operation) is connected,
The outlet of the cooling coil 7 is connected to the suction side of the compressor 1 through a suction pipe 11 having a suction pressure regulating valve 10.

Further, the gas side in the condenser 3 is connected to the protective container 5 through a relief pipe 5 having a leak valve 13 controlled by a temperature detection section 12 that detects the discharge side temperature of the compressor 1.
6, and the protective container 16 is connected to the suction side of the compressor 1 through a connecting pipe 18 having a throttle device 17 that limits the amount of refrigerant gas flowing out according to the pressure on the suction side of the compressor 1.

Note that reference numeral 13 is a signal line, and 17a is a pressure sensitive part of the aperture device.

Next, the operation of the apparatus of the above embodiment will be described.

In the refrigeration operation, the refrigerant from the compressor 1 is transferred to the condenser 3,
This is done in a refrigerant cycle in which the refrigerant returns to the compressor via the expansion valve 4 and the cooling coil 7.

For hot gas defrost operation, close the expansion valve 4,
This is done by opening the defrost valve 8.

The refrigerant gas compressed by the compressor 1 is forced into the cooling coil through the defrost pipe 9 while maintaining a high temperature, thereby defrosting the cooler.

Figure 4 shows this defrost state using a Mollier diagram.At a, which shows the state of the refrigerant at the beginning of defrost, the enthalpy of the refrigerant is still low, but as the defrost operation is performed, the state diagram moves to the right. . This is because the temperature inside the cooling coil increases as the end of defrost approaches, and the refrigerant gas sucked into the compressor 1 at a high temperature is further heated.

When the discharged gas from the compressor 1 reaches the allowable temperature or other set temperature, it is detected by the temperature detector 1.
2 is detected and sends a control signal to the leak valve 13 via the signal line 13a to open the leak valve 13. As a result, a part of the refrigerant gas in the condenser flows into the protective container 16 through the relief pipe 15. This state is shown in Fig. 4b, where the amount of refrigerant gas flowing into the cooling coil 7 is reduced by the action of the leak valve, so the amount of gas sucked into the compressor 1 is limited, and there is no escape means. The pressure of the refrigerant gas is lower than that in the state shown in FIG. 4c.

Note that the refrigerant gas that has flowed into the protective container 16 from the relief pipe is returned to the suction side of the compressor 1 through a throttle device 17 whose pressure is regulated by a signal from a pressure sensing section disposed on the outlet side.

FIG. 2 shows another embodiment, in which the condenser 3
A pressure detecting section 19 is provided in the condenser 3, and the leak valve is opened and closed based on the pressure inside the condenser 3, and the other components are the same as those in FIG.

In this embodiment, the pressure detection unit 19 issues a signal to open the leak valve 13 due to an increase in the pressure inside the condenser 3, and a portion of the high-pressure refrigerant gas enters the protective container and the compressor is activated. protected.

FIG. 3 shows another embodiment in which a temperature detection unit 12 is provided on the discharge side of the compressor 1, and a pressure detection unit 19 is provided in the condenser 3 to detect the pressure inside the condenser.
The other configurations are the same as those in FIG. In this embodiment, the leak valve 13 is opened in response to a signal caused by an increase in temperature on the discharge side of the compressor 1 or an increase in pressure within the condenser 3. As a result, the refrigerant gas is sent to the relief pipe 15, and the temperature of the gas discharged from the compressor is prevented from rising.

As described above, according to the present invention, even in the final stage of defrosting, high-temperature, high-pressure refrigerant gas can be released into the protective container through the escape pipe, and the refrigerant gas stored in the protective container is compressed while being depressurized by the expansion device. Since it is returned to the suction side of the machine, it is possible to suppress the temperature rise of the compressor and prevent seizure and abnormal wear of the piston.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a refrigerant discharge temperature control device for a refrigerator according to the present invention, Fig. 2 is a diagram showing another embodiment in which the leak valve is controlled by a pressure detection section, and Fig. 3 is a diagram showing the leak valve by pressure detection. FIG. 4 is a Mollier diagram in a defrost state, showing another embodiment in which control is performed using both the temperature detection section and the temperature detection section. In the figure, 1... Compressor, 2... Discharge pipe, 3... Condenser, 4... Expansion valve, 5... Liquid feed pipe, 6... Cooler, 7... Cooling coil, 8... Defrost. valve, 9
... Defrost tube, 12 ... Temperature detection section, 13 ...
... Leak valve, 15 ... Relief pipe, 16 ... Protective container, 17 ... Squeezing device, 18 ... Connection pipe, 19 ...
...Pressure detection unit, 10...Suction pressure adjustment valve.

Claims (1)

[Claims] 1 In a refrigerator where the refrigerant from the compressor is sucked into the compressor again through the condenser and the cooling coil of the cooler, the branch is branched from the discharge side of the compressor and is closed during refrigeration operation but opened during defrosting operation. A defrost pipe having a defrost valve is connected to the inlet side of the cooling coil of the cooler, a suction pressure regulating valve is provided in the suction pipe from the outlet of the cooling coil to the compressor, and the gas side of the condenser is connected to the inlet side of the cooling coil of the cooler. Connect to the protective container with a relief pipe that has a leak valve that opens and closes depending on the temperature of the refrigerant on the discharge side of the compressor or the pressure in the condenser, and connect this protective container to the suction side of the compressor with a connecting pipe. , a refrigerant discharge temperature control device for a refrigerator, which is provided with a throttle device in the connecting pipe, the pressure of which is regulated by a pressure sensing section disposed on the outlet side.