JPH0711364B2 - Cooling system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cooling device for controlling the temperature inside a refrigerator or the like by continuously adjusting the amount of a circulating refrigerant.

(B) Conventional Technology A cooling device used in a refrigerator or the like generally forms a compressor, a condenser, an evaporator, and a refrigerant circuit returning to the compressor,
The operation of the compressor is controlled by a thermostat provided in the refrigerator in which the evaporator is arranged so as to maintain a constant temperature in the refrigerator. There is also known a cooling device or the like that does not use a thermostat and adjusts the amount of flowing refrigerant with a flow rate control valve provided in a part of the refrigerant circuit to change the refrigerating capacity of the compressor to maintain a constant low temperature state. .

(C) Problems to be Solved by the Invention However, in a cooling device using a thermostat, the refrigerating capacity of the device itself is always operating in a full state, and it is necessary to have such a large refrigerating capacity that the outside temperature is low, for example, in winter. Even when you don't, you're working hard and putting out wasted abilities. In addition, since the temperature inside the refrigerator is adjusted by using the thermostat, the temperature inside the refrigerator will vary in width and wave due to the difference in performance of the thermostat.

On the other hand, a cooling device that adjusts the amount of refrigerant with a flow rate control valve without using a thermostat can change the refrigerating capacity, so economical operation can be performed, but the degree of throttle of the flow rate control valve that adjusts the amount of circulating refrigerant can be adjusted. Since it depends on the outside air temperature and the internal cooling load, if the outside air temperature becomes extremely low or the internal load becomes too small, the flow control valve will be over-throttled and the suction pressure will increase. On the contrary, there is a danger that the refrigerating capacity will drop, and sometimes the compressor will be below the usage standard and it will not operate normally.

The present invention has been made in view of the above point, without using a thermostat, the refrigerant flow rate is adjusted according to the outside air temperature, the load in the refrigerator, and the compressor is normally operated normally and economically. An object of the present invention is to provide a cooling device capable of maintaining the inside temperature at a constant low temperature.

(D) Means for Solving the Problems In the cooling device of the present invention, a compressor and a condenser are arranged outside the refrigerator and an evaporator is arranged inside the refrigerator so that the refrigerant discharged from the compressor is condensed into the condenser and the evaporator. A flow rate adjusting valve is provided in the suction pipe that returns the refrigerant to the compressor while flowing into the compressor, and the opening / closing degree of the flow rate adjusting valve is controlled according to the internal load and the like to determine the amount of the refrigerant returned to the compressor. In the cooling device that adjusts the refrigerating capacity and keeps the inside of the refrigerator at a constant low temperature, part of the liquid refrigerant discharged from the condenser is diverted, and heat is exchanged in the condenser portion to be gasified. A bypass pipe that allows the refrigerant to flow into the outlet side of the flow rate adjusting valve, an opening / closing valve that is provided on the inlet side of the bypass line, and a suction pipe of the compressor that is provided with the flow rate adjusting valve and the bypass pipe. The pressure of the refrigerant flowing out of the passage and sucked into this compressor is below a specified value. A low pressure switch that operates in the case of the lower case, and when the low pressure switch is operated by narrowing down the flow rate adjusting valve, the on-off valve is opened and the gas refrigerant is made to flow from the bypass pipe to the compressor. It is a thing.

(E) Operation With this configuration, if the suction pressure is above the usage standard of the compressor, the low-pressure switch is inactive, the on-off valve is closed, and the refrigerant is adjusted by the flow control valve to the outside temperature of the internal load. According to the automatic adjustment, the refrigerating capacity is adjusted to operate to maintain a constant temperature inside the refrigerator. Then, when the outside air temperature is too low or the load inside the warehouse is too small, the flow control valve will be throttled too much, and if the suction pressure falls below the usage standard of the compressor, the low pressure switch will detect the low suction pressure. Actuate, resulting in the on-off valve opening. Then, the bypass pipeline is established, and a part of the liquid refrigerant exiting the condenser flows to the bypass pipeline.
A part of the condenser evaporates and becomes a gas, joins the refrigerant that has flowed out of the inflow control valve from the middle of the suction pipe, flows in, and compensates for increasing the gas pressure.

Therefore, the suction pressure to the compressor does not decrease, the compressor operates normally, the operation state with a small refrigerating capacity is continued without any trouble, and the cooling operation without waste and the constant internal temperature can be maintained.

(F) Embodiments The drawings show an embodiment in which the present invention is applied to a refrigerator. FIG. 1 is a refrigerant circuit diagram of a cooling device, and FIG. 2 is an electric circuit diagram of a main part thereof. In FIG. 1, a compressor 2 and a condenser 3 are arranged on the outside 1 of the refrigerator, and an evaporator 5 is arranged on the inside 4 of the refrigerator, with a virtual line (a) in the center as a boundary. The compressor 2 is equipped with a compression motor 6, and when the compressor 2 is operated, the compressed refrigerant gas is discharged by switching the four-way valve 7 to a discharge pipe 8 ′.
The liquid refrigerant condensed into the condenser 3 through the condenser 3 flows through the refrigerant pipe 8 connecting the condenser 3 and the evaporator 5,
Capillary tube 9 provided in the path of the refrigerant pipe 8.
Then, the expansion valve 10 reduces the pressure of the gas into a low-pressure refrigerant gas and flows into the evaporator 5. The refrigerant flowing into the evaporator 5 evaporates there to cool the inside of the refrigerator, and returns from the four-way valve 7 to the compressor 2 via the suction pipe 11. Check valves 12 and 12 'are inserted in parallel in the capillary tube 9 and the expansion valve 10, respectively. Reference numeral 13 is an electromagnetically-operated refrigerant flow rate control valve mounted in the middle of the suction pipe 11 and is a solenoid for driving and controlling the degree of valve opening and closing.
14 and a detector 15 arranged inside the refrigerator for detecting the degree of the load in the refrigerator.
The solenoid 14 detected by 15 is energized and the flow rate control valve 13
To reduce the amount of refrigerant and reduce the overall refrigeration capacity. Although not shown, this control valve 13
Is also adjusted by the outside air temperature detector.

Reference numeral 16 denotes a refrigerant bypass pipe, which branches off in the middle of the refrigerant pipe 8, that is, from where the condenser 3 exits and the capillary tube 9 exits, passes through the condenser 3 portion, and communicates with the suction pipe 11 midway. is doing. Therefore, the portion passing through the condenser 3 forms the heat exchange portion 17, and the condenser 3 is utilized as an evaporator to gasify the depressurized liquid refrigerant and send the gaseous refrigerant to the suction pipe 11. An opening / closing valve 19 operated by a solenoid 18 is provided at the inlet of the bypass conduit 16 and is opened / closed by a low pressure switch described later.

Reference numeral 20 is an expansion valve, and 21 is a sensor unit that controls the expansion valve. twenty two
Is a low-pressure switch that operates by sensing the internal pressure of the suction pipe 11, that is, the suction pressure.When the suction pressure in the suction pipe 11 is low, for example 0.5 kg / cm ² , it is turned on and the solenoid 18 is activated. The power source is energized to open the on-off valve 19 to open the bypass pipe 16. For example, when the pressure reaches 2.5 kg / cm ² , the power is turned off to turn off the solenoid 18 and close the on-off valve 19.

A circuit wiring diagram of the on-off valve 19, the low pressure switch 22 and the compressor motor 6 is shown in FIG. 2, and the compressor motor 6 and the low pressure switch 22 are connected in parallel between the power supply terminals 23 and 23. A solenoid 18 for opening and closing an on-off valve 19 is connected between the normally open contact 24 of the low-voltage switch 22 and the power supply terminal 23 while being inserted.

In the above configuration, the low-pressure switch 22 is not normally operated, the on-off valve 19 is closed, the bypass pipe line 16 is not formed, and the refrigerant is compressed from the compressor 2 → the condenser 3 → the evaporator 5 → the compressor 2. Returning, the inside of the refrigerator 4 is cooled by the evaporator 5.

On the other hand, when the load in the refrigerator becomes too small or the outside air temperature becomes too low, the flow rate control valve 13 is automatically narrowed down, and the refrigerant flow rate decreases. As a result, the refrigerating capacity of the cooling device as a whole is reduced, resulting in an efficient operation. However, at the same time, a situation occurs in which the suction pressure is reduced or the operating operation of the compressor 2 becomes difficult. In such a case, decrease the suction pressure in the suction pipe 11
22 senses and turns on the low-voltage switch 22. By this. The switch is switched to the normally open contact 24 side to energize the solenoid 18 and open the open / close valve 19 to open the bypass pipe 16. Then, a part of the refrigerant flows into the heat exchange section 17 of the condenser 3, where it is heat-exchanged to become a gaseous refrigerant and flows into the suction pipe 11. Therefore, the gas pressure is increased, the normal operation is performed and the interior temperature can be maintained at a constant temperature without compensating for the decrease in the suction pressure to the compressor 2 side and hindering the operation of the compressor 2 at all.

(G) Effects of the Invention As described above, according to the present invention, the internal load is small,
Even if the suction pressure drops to the compressor side due to the decrease in the refrigerant flow rate due to the excessive decrease in outside air temperature, the refrigerant bypass pipe that passes through the condenser is used to send the gaseous refrigerant to the suction side. Can be compensated for, and cooling operation can be performed without any trouble. Therefore, a cooling device having a small refrigerating capacity, producing a resource saving effect, and capable of operating smoothly can be obtained. Also, the compensator is basically a bypass line, an on-off valve attached to the bypass line, and a low-pressure switch installed on the suction side of the compressor that controls the bypass line. There are various effects such as a small number and a simple structure.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a refrigerant circuit diagram,
FIG. 2 is an electric circuit diagram of a main part. 2 ... Compressor, 3 ... Condenser, 5 ... Evaporator, 11 ... Suction pipe, 13 ... Refrigerant flow control valve, 16 ... Bypass line, 17
...... Heat exchange part, 19 ...... Open / close valve, 22 ...... Low pressure switch.

Claims (1)

[Claims] 1. A compressor and a condenser are arranged outside the refrigerator, and an evaporator is arranged inside the refrigerator so that the refrigerant discharged from the compressor flows to the condenser and the evaporator, and the refrigerant is returned to the compressor. The pipe is provided with a flow rate adjusting valve, the opening / closing degree of the flow rate adjusting valve is controlled according to the load in the refrigerator, etc., and the refrigerating capacity is changed by adjusting the amount of refrigerant returned to the compressor to change the inside of the refrigerator. In a cooling device capable of maintaining a constant low temperature state, a part of the liquid refrigerant discharged from the condenser is diverted, and the refrigerant gasified by heat exchange in the condenser part is flown into the outlet side of the flow rate adjusting valve. A bypass pipe, an opening / closing valve provided on the inlet side of the bypass pipe, a suction pipe of the compressor, and a refrigerant that flows out from the flow rate adjusting valve and the bypass pipe and is sucked into the compressor. Is equipped with a low pressure switch that is activated when the pressure of the , Wherein the low pressure switch is actuated by the narrowing of the flow control valve, the cooling apparatus characterized by flow by opening the on-off valve from the bypass line of the gas refrigerant to the compressor.