JPH0552430A - Refrigerating machine - Google Patents

Abstract

PURPOSE:To free the operation, even where a general-purpose temperature controller having no limiter is in use, from the problem that the suction pressure of the compressor may decrease excessively by providing in parallel with a flow-rate control valve a bypass equipped with a means of resistance to refriger ant. CONSTITUTION:In parallel with a flow-rate control valve 5, which is placed between an evaporator 4 and the inlet of a compressor 1 for the control of the flow-rate of the refrigerant 1a, a bypass 10 equipped with a capillary tube 9 as a means of resistance to the refrigerant 1a is provided. Even when, for example, the heat load has considerably fallen owing to some cause and a signal from a temperature controller 7 brings the flow-rate control valve 5 to a complete closure in valve opening or to a throttled state close to a complete closure, the refrigerant 1a keeps flowing into the compressor 1 in small amounts so that there is no possibility of the suction pressure being reversed to a negative pressure at the compressor 1. Thus, this method enables the refrigerating machine to continue to operate normally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precise temperature of an object to be cooled, such as a water cooling type cooling device for cooling a semiconductor element using water as a cooling medium and a cooling device for cooling cutting oil for machine tools. The present invention relates to a refrigerator used in a device that needs to be controlled, and more particularly to an improved structure for preventing an excessive decrease in suction pressure of a compressor mounted on the refrigerator.

[0002]

2. Description of the Related Art In a semiconductor element cooling device, since the operating temperature of the semiconductor element is strictly regulated, the precise temperature of the cooling water or the cooling oil, which is the cooling liquid, is adjusted in response to the fluctuation of the heat value of the semiconductor element. Control is required. FIG. 4 is a refrigerant circuit diagram of a conventional refrigerator used in such a cooling device. In FIG. 4, reference numeral 1 denotes a compressor for sucking the refrigerant 1a from the suction port, compressing it under pressure, and discharging it from the discharge port.
Reference numeral 2 is a condenser for cooling the refrigerant 1a that has been compressed by the compressor 1 and has a high temperature, 3 is an expansion valve for expanding the refrigerant 1a that has been compressed by the compressor 1 and has a high pressure, and 4 is that the refrigerant 1a is evaporated. To cool the cooling liquid, which is the object to be cooled, 8 is a conduit through which the cooling liquid flows, and 5 is an evaporator 4.
And a flow rate adjusting valve inserted between the suction port of the compressor 1 and
Reference numeral 6 denotes a temperature sensor arranged in the cooling liquid pipe 8 for detecting the temperature of the cooling liquid, and 7 denotes a temperature controller for outputting a valve opening signal to the flow rate adjusting valve 5 using the output of the temperature sensor 6 as an input signal.

In the above configuration, first, the temperature controller 7
The temperature sensor 6 detects the temperature of the cooling liquid in the evaporator 4 by the control system of the flow rate adjusting valve 5 and the flow rate adjusting valve 5.
The temperature control of the cooling liquid is performed by adjusting the valve opening degree and the flow rate of the refrigerant 1a. That is, for example, the heat load is reduced by reducing the loss generated by the semiconductor element,
When the temperature of the cooling liquid starts to decrease, the temperature sensor 6 detects this temperature change and throttles the valve opening of the flow rate adjusting valve 5 to cool the refrigerant 1
The flow rate of a is reduced and the refrigerating capacity of the refrigerator is reduced so as to balance with the heat load. As a result, the temperature of the cooling liquid can be precisely controlled regardless of the heat load.

[0004]

The refrigerator according to the prior art described above is capable of precisely controlling the temperature of the cooling liquid, but the valve opening of the flow rate adjusting valve varies from fully open to fully closed depending on the heat load. Can be changed. Therefore, if the temperature setting value of the temperature controller is set higher than the current temperature of the cooling liquid, or if the heat load is significantly reduced for some reason, etc., the flow rate control valve will be activated by the signal from the temperature controller. The valve opening of may be closed or may be close to a closed state. When the valve opening of the flow rate adjusting valve is fully closed or closed to a state close to full closing, the suction pressure of the compressor becomes a negative pressure, which causes an excessive temperature rise in the refrigerant gas discharged from the compressor. There is a problem that the refrigerant gas is decomposed and the compressor driving electric motor is burnt out. As a measure against this problem,
A possible method is to provide a limiter on the temperature controller to prevent the flow control valve from closing below the desired opening, but in this case a general-purpose temperature controller does not have a limiter and the desired opening However, there is a problem in that an expensive dedicated temperature controller must be used since each cooling device also differs depending on the individual cooling device.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to dispose a bypass flow passage having a resistance means for refrigerant in parallel with a flow rate adjusting valve,
It is an object of the present invention to provide a refrigerator for a cooling device that can eliminate the problem that the suction pressure of the compressor is excessively reduced even if a general-purpose temperature controller having no limiter is adopted.

[0006]

In the present invention, the above-mentioned objects are as follows: 1) an evaporator for generating cold heat by evaporating a refrigerant;
A compressor that sucks in and compresses the low-pressure refrigerant evaporated in this evaporator from the suction port and discharges it from the discharge port; and a condenser that cools the high-temperature refrigerant compressed by this compressor, An expansion valve connected downstream of the condenser for expanding the high-pressure refrigerant compressed by the compressor, and for adjusting the flow rate of the refrigerant inserted between the evaporator and the suction port of the compressor. In the refrigerator equipped with the flow rate adjusting valve of
A bypass flow path provided with a resistance means for the refrigerant is arranged in parallel with the flow rate adjusting valve, and 2) in the means of the above item 1, the resistance means is a capillary tube, and 3) in the above item 1. In the means, the resistance means is achieved by being a manually regulated valve.

[0007]

In the present invention, the bypass means having the resistance means for the refrigerant is arranged in parallel with the flow rate adjusting valve in the above-mentioned configuration, so that the resistance means is provided even if the flow rate adjusting valve is fully closed. Since a small amount of refrigerant flows into the compressor via the above, the suction pressure of the compressor is prevented from becoming a negative pressure.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a refrigerator according to an embodiment of the present invention. The same parts as those in the conventional example of FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 1, reference numeral 9 denotes a bypass flow passage 10 for the refrigerant 1a formed in parallel with the flow rate adjusting valve 5.
It is a capillary tube as a resistance means of the refrigerant 1a connected to. Since the present invention has the above-described configuration, for example, even when the heat load is significantly reduced for some reason and the flow rate adjusting valve 5 is fully closed by the signal of the temperature controller 7,
Since a small amount of the refrigerant 1a flows through the capillary tube 9 and flows into the compressor, the suction pressure of the compressor is prevented from becoming a negative pressure, and the compressor continues normal operation. At this time, the temperature of the cooling liquid gradually returns to the set value. The inner diameter and the length of the capillary tube 9 are such that the suction pressure of the compressor does not become a negative pressure when the flow rate adjusting valve 5 is fully closed, so that the temperature rise value at which the refrigerant gas discharged from the compressor is allowed is maintained. The refrigerant 1a is set to flow so as not to exceed the usage limit.

FIG. 2 is a refrigerant circuit diagram of a refrigerator according to another embodiment of the present invention. The same parts as those of the embodiment of the present invention shown in FIG. 1 and the conventional example shown in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, reference numeral 11 is a manual adjustment valve that is connected to the bypass circuit 10 and serves as a resistance unit for the refrigerant 1a. Also in the case of this configuration, the same operation as in the case of the embodiment of the present invention according to FIG. Moreover, by appropriately adjusting the valve opening degree of the manual adjustment valve 11, the flow rate of the refrigerant 1a flowing through the bypass passage 10 when the flow rate adjustment valve 5 is fully closed is optimally set according to the operating condition of the cooling device. It is possible to obtain a more preferable effect.

FIG. 3 is a refrigerant circuit diagram of a refrigerator to which an embodiment of the present invention is applied. The difference from the embodiment of the present invention shown in FIG. 1 is that the embodiment of the present invention shown in FIG.
This is a combination of the techniques known in Japanese Patent No. 6853 that expand the capacity control range of a refrigerator. That is, the refrigerant bypass pipe 12 connecting the discharge port of the compressor 1 and the inlet side of the evaporator 4
The refrigerant bypass pipe 12 is provided with a refrigerant bypass valve 13 that starts a valve opening operation when the refrigerant pressure on the suction side of the compressor 1 reaches a preset set pressure. is there. With this configuration, when the suction side pressure of the compressor 1 drops to this set pressure, the refrigerant bypass valve 13 starts the valve opening operation, and the compressor 1
Part of the high-temperature refrigerant gas discharged by the refrigerant bypass pipe 12
The bypass is directly applied to the evaporator 4 to give a simulated load to the evaporator 4, and in this state, the refrigerating capacity and the refrigerating load are balanced. As a result, in addition to the operation of the configuration of the embodiment of the present invention shown in FIG. 1, a wider capacity control of the refrigerator can be performed. Of course, the configuration according to FIG. 3 can be applied to the case of a different embodiment of the present invention shown in FIG.

[0011]

According to the present invention, by disposing the bypass circuit having the resistance means for the refrigerant in parallel with the flow rate adjusting valve, for example, the thermal load is significantly reduced for some reason, and the temperature controller is controlled. Even if the valve opening of the flow rate adjustment valve is throttled to the fully closed state or a state close to the fully closed state by the signal from, the inflow of a small amount of refrigerant to the compressor is maintained. There is no negative pressure, the refrigerator can continue normal operation, and this can be achieved even by adopting a general-purpose temperature controller that does not have a limiter. It is possible to reduce the cost.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigerator according to an embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram of a refrigerator according to another embodiment of the present invention.

FIG. 3 is a refrigerant circuit diagram of a refrigerator to which an embodiment of the present invention is applied.

FIG. 4 is a refrigerant circuit diagram of a refrigerator according to the related art.

[Explanation of symbols]

 1 Compressor 1a Refrigerant 2 Condenser 3 Expansion valve 4 Evaporator 5 Flow rate control valve 7 Temperature controller 9 Resistance means (capillary tube) 10 Bypass flow path 11 Resistance means (manual adjustment valve)

Claims (3)

[Claims] 1. An evaporator that produces cold heat by evaporating a refrigerant, and a compressor that sucks in and compresses a refrigerant that has been evaporated in this evaporator and has a low pressure through a suction port, and pressurizes and compresses it. A condenser that cools the high-temperature refrigerant that is compressed by the compressor, an expansion valve that is connected downstream of the condenser and that expands the high-pressure refrigerant that is compressed by the compressor, the evaporator, and the evaporator. In a refrigerator equipped with a flow rate adjusting valve for adjusting the flow rate of the refrigerant inserted between the suction ports of the compressor, a bypass flow path provided with a resistance means for the refrigerant is arranged in parallel with the flow rate adjusting valve. A refrigerator characterized by being installed. 2. The refrigerator according to claim 1, wherein the resistance means is a capillary tube. 3. The refrigerator according to claim 1, wherein the resistance means is a manual adjustment valve.