JPH05172408A - Refrigerator - Google Patents

Abstract

PURPOSE:To reduce the frequency of power supply of a solenoid valve by opening a first stage solenoid valve when the temperature of discharge gas exceeds a specified value and opening a second stage solenoid valve when the temperature further rises and reaches a specified value. CONSTITUTION:When the temperature of discharge gas of a compressor exceeds a specified value, a first stage solenoid valve 5 is opened where the refrigerant whose pressure is reduced by a capillary tube 7 is sprayed so that the discharge gas may be cooled on the way of compression process. Furthermore, when a first stage bypass volume is insufficient and the temperature of discharge gas exceeds the next specified value, a second stage solenoid valve 6 is opened so that the gas may be sprayed in the same manner with a capillary tube 8 and cooled. In this manner, the temperature of discharge gas is set to two stages so that a two sage-based bypass circuit may be formed with the capillary tubes 7 and 8, thereby forming a bypass circuit of a proper amount of refrigerant. This construction makes it possible to set proper the refrigerant bypass volume and reduce the frequency of power supply of each of the solenoid valves 5 and 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle, and relates to a refrigerating apparatus for controlling discharge gas temperature.

[0002]

2. Description of the Related Art Prior art (Japanese Patent Laid-Open No. 1-269866)
Is a refrigeration cycle that has a bypass circuit that opens and closes a solenoid valve according to the discharge gas temperature, bypasses a portion of the high-pressure liquid refrigerant during the compression process, cools the compressor, and controls the discharge gas temperature. .

[0003]

The above-mentioned prior art is suitable for operation at a high evaporation temperature in a refrigerator having a wide evaporation temperature range (about -45 ° C to + 5 ° C) because there is only one bypass circuit. Even in the bypass circuit for the circulation amount of high-pressure liquid refrigerant, the circulation amount becomes excessive in the operation with a low evaporation temperature, the temperature of the discharge gas drops rapidly when the solenoid valve is opened, and the solenoid valve is repeatedly opened and closed in a short time. There was a problem that the number of energizations increased and the solenoid valve failed in a short period of time.

An object of the present invention is to solve this problem and reduce the energizing circuit of the solenoid valve.

[0005]

In order to achieve the above object, the present invention uses two bypass circuits, and the circulation amount of each bypass circuit is half the required circulation amount. By controlling the bypass circuit of these two circuits by the discharge gas temperature, an appropriate circulation amount can be achieved, and the number of times of energization of each solenoid valve is averaged.

[0006]

[Function] The discharge gas temperature is detected by a controller composed of a thermistor, a microcomputer, etc., and two switching temperatures are set to this discharge gas temperature, and the solenoid valve is fully closed and only one circuit is set by this set temperature. By controlling the switching to open and to open both circuits together, a proper circulation amount is achieved, and the number of times the solenoid valve is energized can be reduced.

Further, when only one circuit is opened, two circuits are alternately switched and used in accordance with the opening and closing of the solenoid valve, and the number of energization of each bypass circuit solenoid valve is averaged.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a system diagram of a refrigeration cycle. In FIG. 1, the compressor 1, the condenser 2, the expansion valve 3 and the evaporator 4 constitute a basic refrigeration cycle. The compressor 1 has a volumetric shape such as a scroll or a screw. From the high-pressure liquid pipe exiting from the condenser 2 to the middle of the compression process of the compressor 1, the first-stage solenoid valve 5 and the first-stage capillary tube 7 or the second-stage solenoid valve 6 and the second-stage capillary tube 8 To form a bypass circuit. When the temperature of the gas discharged from the compressor 1 exceeds a predetermined temperature, the electromagnetic valve 5 is opened, and the pressure-reduced refrigerant is injected by the capillary tube 7 to cool the gas discharged during the compression process. Further, when the first-stage bypass amount is insufficient and the discharge gas temperature becomes equal to or higher than the next predetermined temperature, the second-stage solenoid valve 6 is also opened, and the capillary tube 8 similarly injects and cools. is there.
The discharge gas temperature is detected by attaching a thermostat to the discharge gas pipe or by using a thermistor or the like, and detailed description thereof will be omitted. By setting the discharge gas temperature in two stages and forming a two-stage bypass circuit, a bypass circuit with an appropriate refrigerant circulation amount becomes possible.

In the present invention, the first stage capillary tube 7
The pressure reduction value of the second stage capillary tube 8 is made the same, and the number of times of energization of the solenoid valves 7 and 8 is averaged by alternately switching between operating and stopping the refrigeration system. When the discharge gas temperature rises to the predetermined temperature of the first point, the first-stage solenoid valve 5 is opened, but after the refrigeration system is stopped and restarted, 2
The solenoid valve 6 of the stage is opened as the first stage.
With this method, the number of times of energization of the first-stage solenoid valve 5 and the second-stage solenoid valve 6 can be averaged, and it is possible to prevent early failure of the first-stage solenoid valve, which is frequently used for energization.

[0010]

According to the present invention, it is possible to optimize the liquid refrigerant bypass amount, reduce the number of times each solenoid valve is energized, and average each number of solenoid valve energizations.

[Brief description of drawings]

FIG. 1 is a system diagram of a refrigeration cycle showing an embodiment of the present invention.

[Explanation of symbols]

1 ... Compressor, 2 ... Condenser, 3 ... Expansion valve, 4 ... Evaporator, 5
... 1st-stage solenoid valve, 6 ... 2nd-stage solenoid valve, 7 ... 1st-stage capillary tube, 8 ... 2nd-stage capillary tube.

Claims (1)

[Claims] 1. In a refrigeration cycle using a positive displacement compressor, two circuits of the same refrigerant circulation amount are provided for bypassing a part of the high pressure liquid refrigerant in the middle of the compression process, and the discharge gas temperature exceeds a certain temperature. If the first-stage solenoid valve is opened when the temperature rises and the discharge gas temperature rises above a certain temperature, 2
A refrigeration system characterized by opening a stage solenoid valve.