JPS6145141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system that cools a plurality of show cases used in supermarkets and the like with a single condensing unit, and in particular, during defrosting, a high temperature liquid refrigerant is passed through an evaporator, It concerns the flow of refrigerant used for defrosting into the evaporator during cooling.

In general, using liquid refrigerant for defrosting after leaving the condenser is more effective than using gas refrigerant.
It is easy to regulate the amount of refrigerant to the evaporator, and its temperature is lower than that of gas refrigerant, making it effective in eliminating excessive temperature rises inside the refrigerator. However, there is a drawback that the liquid refrigerant remaining in the evaporator is sucked into the low pressure side of the refrigeration system immediately after defrosting, exceeding the capacity of the accumulator and causing the compressor to compress the liquid.

The present invention eliminates such drawbacks and will be described below with reference to one embodiment shown in the drawings.

1 is a compressor, 2 is a condenser, 3 is a receiver tank, and 4 is a high-pressure side branch pipe. 5 and 6 are expansion valves with check valves 7 and 8 installed in parallel, 9 and 10 are evaporators, 11 and 12 are low-pressure solenoid valves, 13 is a low-pressure side branch pipe, and 14 is an accumulator, which is a well-known evaporator. Refrigeration system 100 in which containers 9 and 10 are connected in parallel
is formed. Reference numeral 11a designates a defrost pipe having an inlet opening in the liquid refrigerant portion at the bottom of the receiver tank 3, and is connected to the outlet sides of the evaporators 9 and 10 via defrost solenoid valves 14 and 15, respectively. A bypass pipe 16 bypasses the condenser 2 and connects to the defrost pipe 11a, and selectively introduces liquid refrigerant or gaseous refrigerant into the evaporators 9 and 10 via a valve device 17 such as a three-way switching valve. I have made it possible.

Next, the operating state of the above configuration will be explained with reference to FIG. 2.

During the cooling operation, the refrigerant gas compressed by the compressor 1 is liquefied in the condenser 2, and is transferred to the receiver tank 3,
It passes through the high-pressure branch pipe 4, passes through both expansion valves 5 and 6, is evaporated in the evaporators 9 and 10, passes through the open low-pressure solenoid valves 11 and 12, and goes to the low-pressure branch pipe 13 and the accumulator 14. The cooling effect is carried out by the circulation from the compressor to the compressor.

Next, the case of defrosting the evaporator 9 will be explained. The defrost solenoid valve 15 is opened, the valve device 17 is in the first position to flow liquid refrigerant from the receiver tank 3 to the defrost pipe 11a, and the liquid refrigerant enters the evaporator 9 and then passes through the check valve 7 to the high pressure side branch pipe. 4, the liquid refrigerant is mixed with the liquid refrigerant in the receiver tank 3, and evaporated in the evaporator 10 during cooling. As defrosting progresses, at the end, the valve device 17 is switched to guide the gaseous refrigerant to the evaporator 9 through the bypass pipe 16, and discharge the liquid refrigerant stored in the evaporator 9.
Finish defrosting, close the defrost solenoid valve 15,
At the same time, the low pressure side solenoid valve 11 is opened to return to cooling operation.

As described above, the present invention defrosts using a liquid refrigerant and introduces the defrosted refrigerant into an evaporator that is being cooled. This system is equipped with a bypass pipe equipped with a valve device that allows high-temperature gaseous refrigerant to flow into the evaporator during defrosting for a predetermined period of time before the end of defrosting. This system discharges the liquid refrigerant and returns to cooling operation. Unlike conventional systems, when returning to cooling operation, the liquid refrigerant flows into the low-pressure piping, allowing smooth refrigeration without causing liquid compression in the compressor. Must be able to operate the equipment.

[Brief explanation of the drawing]

FIG. 1 is a system circuit diagram of a refrigeration device showing an embodiment of the present invention, and FIG. 2 is a flow chart explaining the operating state of the device. 1... Compressor, 2... Condenser, 5, 6... Expansion valve, 9, 10... Evaporator, 11a... Defrost pipe, 14, 15... Defrost solenoid valve, 16...
Bypass pipe, 17...valve device.

Claims (1)

[Claims] 1 A compressor, a condenser, a plurality of evaporators, an expansion valve, and a defrost pipe equipped with a defrost solenoid valve that selectively flows high-temperature liquid refrigerant between the outlet side of the condenser and the outlet side of the evaporator. , in which the refrigerant that has been used to defrost one evaporator flows to the other evaporator that is being cooled, wherein a high-temperature gaseous state is passed between the compressor and the condenser and the defrost pipe for a predetermined period of time before the end of defrosting. A defrosting device for a refrigeration system equipped with a bypass pipe equipped with a valve device such as a three-way switching valve that allows refrigerant to flow into the evaporator during defrosting.