JPS6196367A - Air-cooling refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention inserts an expansion valve having a temperature sensitive part for detecting temperature and a pressure sensitive part for detecting pressure into a refrigeration cycle.

The present invention relates to a cooling/refrigeration system that controls an expansion valve based on the temperature and pressure detected by a temperature sensing part and a pressure sensing part.

BACKGROUND OF THE INVENTION Generally, in an air-conditioning refrigeration system using a refrigeration refrigerant such as Freon gas, as shown in FIG. The liquid refrigerant is made into a low-pressure liquid refrigerant by increasing the fluid resistance with the cavillary tube or the expansion valve 2, which is used as the evaporator 6.The surrounding heat is absorbed in the heat exchanger, and the low-temperature, low-pressure refrigerant is converted into a sliver-like refrigerant, which is then transferred to the compressor again. A refrigerating cycle is formed at 7'. One of the factors that determines the temperature of the gaseous refrigerant discharged by the compressor 7 is the degree of superheating of the gaseous refrigerant sucked into the compressor 7, that is, the temperature difference from saturated steam. Under normal conditions, in the external equalization type expansion valve 2, the temperature or pressure of the refrigerant at the evaporator outlet 5 is detected by the temperature sensing part 3 and the pressure sensing part 4 included in the expansion valve 2, and the output is For example, the expansion valve 2 is throttled to obtain an appropriate degree of superheating of about 5° C., and the flow rate of the refrigerant is adjusted to be small. However, in reality, a suction hose is inserted between the evaporator outlet 5 and the compressor suction point 8, so the pressure of the gaseous refrigerant decreases enthalpically, and the degree of superheat exceeds the suction pressure of the upper compressor 7. lower.

Problems to be Solved by the Invention The compressors 7 conventionally used in air-conditioning/refrigeration systems for automobiles have been replaced by rotary type compressors such as vane type and scroll type, from reciprocating type compressors. Since this rotary compressor 7 has few factors that inhibit the inflow efficiency of the gaseous medium that is normally drawn in, high volumetric efficiency can be obtained even when the flow rate is high or the compression ratio is high. However, in automobiles, the engine that drives the compressor 7 has a wide rotation speed range, so when the carrot rotates at high speed, the capacity tends to be excessive, and when the carrot rotates at high speed, the suction pressure of the compressor 7 decreases significantly. , there is a drawback that the temperature of the gaseous medium discharged by the compressor 7 rises abnormally.

Means for Solving the Problems The present invention provides a temperature sensing system for an expansion valve 2 that detects the temperature in a cooling refrigeration circuit in which an external expansion valve 2 is inserted between a condenser 1 and an evaporator 6 in a refrigeration cycle. The part 3 is connected to the evaporator outlet 5, and the pressure sensing part 4 for detecting pressure is connected to the suction pipe near the compressor 7, or to the compressor suction point 8 or the temperature sensing part 3. The compressor 7 is a cooling and refrigerating system in which both the pressure sensing parts 4 are connected to the compressor suction point 8 degrees or a throttle valve is inserted in the refrigerant path between the pressure sensing position of the pressure sensing part 4 and the temperature sensing part 3. The purpose is to reduce the temperature of the gaseous refrigerant discharged from the

Operation Therefore, the means of the present invention is based on the temperature sensing portion 3 provided in the expansion valve 2.
By simply changing the location of the pressure sensitive section 4, the temperature of the gaseous refrigerant discharged from the compressor 7 can be maintained appropriately even when the compressor 7 rotates abnormally.

Embodiment As shown in FIG. 1, an embodiment of the cooling/refrigeration system of the present invention is provided with a temperature-sensing section 3 of an expansion valve 2 for detecting temperature at the evaporator outlet 5, and a pressure-sensing section of the expansion valve 2 for detecting pressure. 4 is provided at a compressor suction point 8 near the suction port of the compressor 7.

When the refrigerant flow rate is low, the pressure loss occurring in the suction hose 10 is negligible, so the expansion valve 2 is controlled by the detected pressure at the evaporator outlet 5 as in the conventional case. However, when the engine speed increases, the speed of the compressor 7 driven by the engine also increases, and the flow rate of the refrigerant also increases, so the pressure loss in the suction hose 10 increases and the pressure at the compressor suction point 8 decreases. The pressure in the pressure section 4 also decreases. In this case, the temperature sensing part 3 of the evaporator outlet 5 causes the expansion valve 2 to
However, since the pressure at this point is higher than the pressure at the compressor suction point 8, it is higher than the evaporation temperature corresponding to the pressure detected by the pressure sensitive section 4.

Therefore, even if the degree of superheat is substantially low, the apparent degree of superheat seen from the expansion valve 2 side is considered to be higher, and the expansion valve 2 increases the opening degree and lowers the actual degree of superheat. That is, the larger the pressure loss in the suction hose 10, the smaller the degree of superheating. 2 shows a second embodiment of the present invention in which both the pressure sensitive part 4 and the heat sensitive part 3 of the expansion valve 2 are provided at the compressor suction point 8. Although this means does not have the effect of reducing the degree of superheat even when the compressor 7 rotates at high speed and the flow rate is large, it has no effect on the pressure due to the pressure loss of the suction hose 10, and it makes it possible to keep the degree of superheat at the compressor suction point 8 constant. Can be done.

Further, FIG. 3 shows a third embodiment of the present invention, in which a throttle valve 9 is provided to cope with the pressure loss in the suction hose 10, and the suction pressure of the compressor 7 is lowered in a large flow rate range, thereby reducing the discharge from the compressor 7. This can prevent the temperature of the gaseous medium from rising.

Effects of the Invention As described above, according to the present invention, the suction pressure of the compressor 7 generated by replacing the reciprocating compressor with a rotary compressor can be lowered, and the temperature of the discharged gaseous refrigerant can be lowered by simple means.

[Brief explanation of drawings]

FIG. 1 is a cooling refrigeration circuit diagram showing a refrigeration cycle in an embodiment of a cooling refrigeration system according to the present invention, FIG. 2 is a cooling refrigeration circuit diagram in a second embodiment according to the present invention, and FIG. Cooling/refrigeration circuit diagram in the example of 4th
The figure is a conventional cooling/refrigeration circuit diagram. Note: 1: Condenser, 2: Expansion valve, 3: Temperature sensing part, 4: Pressure sensing part, 5
: Evaporator outlet, 6: Evaporator, 7: Compressor. 8: Compressor suction point, 9: Throttle valve, 10: Suction hose O Figure 1 Figure 2 Figure 3 Tail Figure 4

Claims (3)

[Claims] 1. The gaseous refrigerant compressed in the compressor 7 is condensed in the condenser 1, and the high-pressure liquid refrigerant is lowered in pressure in the expansion valve 2, and the surrounding area is cooled in the evaporator 6, and then returned to the compressor 7 for cooling. In the refrigeration circuit, the expansion valve 2 has a temperature sensing section 3 and a pressure sensing section 4.
In a refrigeration circuit using an expansion valve that automatically adjusts the degree of superheating of the refrigerant, the temperature sensing section 3 is disposed at the evaporator outlet 5, and the pressure sensing section 4 is disposed at the compressor suction point 8. A cooling/refrigeration system characterized in that the throttle of the expansion valve 2 is automatically controlled. 2. The cooling/refrigeration system according to claim 1, wherein the temperature sensing section 3 and the pressure sensing section 4 are both disposed at the compressor suction point in the cooling/refrigeration circuit. 3. Claim 1: A throttle valve 9 is inserted into a conduit between a temperature sensing section 3 disposed at the evaporator outlet 5 and a pressure sensing section 8 disposed at the compressor suction point 8 in the cooling refrigeration circuit. The cooling/refrigeration equipment described in Section 1.