JPH09133413A - Freezing cycle of refrigerant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a compressor from being rendered in the state of liquid compression by using only a partial interval of a refrigerant return pipe as a parallel piping, and operating a two-way valve provided on the one piping by actuating the same such that compressor interruption and full close of the same are brought into synchronism and that timing of full open is delayed with respect to operation starting. SOLUTION: A refrigerant return pipe 5 coupling an evaporation pipe 4 and a compressor 1 is branched at a branch part 5a, on one of which a two-way valve 8 is disposed and on the other of which an auxiliary capillary tube 9 is disposed. They are joinned at a joint part 5b as one piping. A refrigerant that is balanced in its high pressure part and low pressure part upon interruption of the compressor 1, and is directed to flow into the evaporator 4 where it is stored in an air/liquid mixed state flows into the compressor 1 through the refrigerant return pipe 5 simultaneously with the starting of compressor operation. Herein, the two- way valve 8 is kept fully closed for a predetermined time just after the starting of the operation of the compressor 1 whereby the returned refrigerant from the evaporator 4 is returned to the compressor through the auxiliary capillary tube 9. Thereafter, the two-way valve 8 is fully opened to bring the operation to stationary one. Further, the two-way valve 8 is fully closed upon the operation interruption of the compressor 1, and hence a reverse flow of the liquid refrigerant from a suction side circuit is prevented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a refrigerating cycle for a refrigerator.

[0002]

2. Description of the Related Art In refrigerators, the temperature inside the refrigerator is usually controlled by stopping the operation of the compressor. When the compressor is stopped, the high temperature and high pressure refrigerant in the condenser is in the evaporator through the pipe. In the refrigeration cycle using the rotary compressor, the refrigerant and the lubricating oil flow into the low-pressure side pipe including the evaporator from the sliding portion clearance in the compressor, which causes the temperature rise of the evaporator. , Liquefied refrigerant in the evaporator,
Also, the lubricating oil that has flowed out into the low-pressure side pipe instantly returns to the inside of the compressor at the start of operation of the compressor, which causes poor thermal efficiency and impairs the reliability of the compressor.

In order to solve this problem, for example, as disclosed in JP-A-62-255772, a flow control valve driven by a step motor or the like is provided between the evaporator and the capillary tube to start the compressor. An invention has been proposed that avoids a sudden liquid refrigerant return phenomenon at the time of starting the compressor by sensing the subsequent time change of the evaporator inlet temperature and adjusting the opening of the flow control valve.

[0004]

However, in the case of the above invention, the control of the opening of the flow control valve becomes complicated, and the flow control valve and the step motor, the temperature sensor, etc. for controlling the flow control valve are required. It causes problems such as price increase.

The present invention has been proposed to solve the above problems.

That is, at the time of starting the operation of the compressor, the liquid refrigerant stored in the evaporator may be directly sucked into the compressor to cause liquid compression, which may impair the reliability of the compressor. It was proposed as a method to prevent this.

The object of the present invention is to make a partial section of the suction pipe connecting the evaporator and the compressor into parallel piping, to completely close one side circuit at the start of operation, and to pass all the refrigerant through the auxiliary capillary tube side. The refrigerant is changed to a gas state and sucked into the compressor.

[0008]

In order to achieve the above object, the present invention has a two-way valve provided on one side of a refrigerant return pipe extending from an evaporator outlet into a machine chamber and extending in the machine chamber. The installed refrigerant return pipe and the other side are two refrigerant return pipes connected in parallel with an auxiliary capillary tube. When the compressor is stopped, the two-way valve is held in a fully closed state. For example, the two-way valve is fully opened after a delay of about 1 to 10 minutes from the start.

In a refrigeration cycle using a rotary compressor in which the compressor is a high-pressure container, a check valve is arranged in series in the suction pipe on the compressor side.

According to the present invention, with the above-described structure, the operation of fully opening the two-way valve is delayed with respect to the start of operation of the compressor so that the liquid refrigerant returned from the evaporator at the same time as the start of operation is stored in the auxiliary capillary tube. The liquid refrigerant is prevented from being directly sucked into the compressor by passing the liquid refrigerant into a gas state so that the gas refrigerant is sucked into the compressor. In a refrigeration cycle using a rotary compressor, the check valve prevents the lubricating oil and high-temperature refrigerant from flowing out of the container to the low-pressure side pipe when the compressor is stopped, and the lubricating oil and liquid refrigerant return at the start of operation. Avoid the phenomenon more effectively.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
This will be described with reference to the drawings.

The refrigeration cycle of the present invention is constructed as shown in FIG. That is, in the refrigeration cycle in which the compressor 1, the condenser 2, the capillary tube 3, and the evaporator 4 are connected in a closed circuit, the refrigerant return pipe 5 that connects the evaporator 4 and the compressor 1
Is provided with two parallel circuits, one of which is a refrigerant return pipe 7 in which a two-way valve 8 is arranged, and the other is a refrigerant return pipe 6 in which an auxiliary capillary tube 9 is arranged in the middle. In part 5b, they join again into one pipe.

In the refrigerating cycle thus formed,
When the compressor 1 is stopped, the refrigerant that has flowed into the evaporator 4 to balance the high pressure portion and the low pressure portion and is stored in the gas-liquid mixed state is transferred to the inside of the compressor through the refrigerant return pipe 5 at the same time when the compressor operation is started. Flow into.

Here, in the refrigerant return pipe constructed as in the present invention, the two-way valve 8 is held in the fully closed state for a few minutes (for example, for 1 minute to 10 minutes) immediately after the operation of the compressor 1 is started. By doing so, all the return refrigerant from the evaporator 4 is returned to the compressor 1 via the auxiliary capillary tube 9. After that, the two-way valve 8 is fully opened, and the operation shifts to steady operation.
Note that when the compressor is stopped, the two-way valve 8 is fully closed, and the backflow of the liquid refrigerant via the suction side circuit is blocked.

As shown in FIG. 2, the discharge pressure and the suction pressure of the refrigerating cycle thus constructed have a gradual increase in the discharge pressure as compared with the conventional refrigerator immediately after the start of operation of the compressor. Since the suction pressure sharply decreases, the effect of reducing the load immediately after the compressor is started can be obtained, and the efficiency of the compressor motor can be improved and the power saving effect of the refrigerator can be expected.

On the other hand, in the case of a compressor, such as a rotary compressor, in which the inside of the container is kept in a high pressure state during operation, the refrigerant and the lubricant flowing out to the low-pressure pipe side through the sliding portion clearance at the same time when the compressor stops. In order to suppress the amount of oil as small as possible, the check valve 10 is arranged immediately before the compressor suction portion of the refrigerant return pipe, whereby a more effective effect can be obtained for preventing liquid compression.

[0017]

According to the present invention, the refrigerant return pipe from the evaporator to the compressor is partially arranged in parallel, and the check valve is arranged immediately in front of the compressor suction pipe. It is possible to prevent and provide a highly reliable refrigeration cycle.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a refrigerator refrigeration cycle of the present invention.

FIG. 2 is an explanatory diagram of a load change of the refrigeration cycle according to the present invention.

[Explanation of symbols]

1 ... Compressor, 2 ... Condenser, 3 ... Capillary tube, 4
... Evaporator, 5 ... Refrigerant return pipe, 5a ... Branch part, 5b ... Merging part, 6 ... Refrigerant return pipe, 7 ... Refrigerant return pipe, 8 ... Two-way valve, 9
… Auxiliary capillary tube, 10… Check valve.

 ─────────────────────────────────────────────────── --- Continuation of front page (72) Inventor Shinichi Sato 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Hitachi Co., Ltd. Cooling & Heat Business Department (72) Inventor Takehiro Kaneko 709 Tomita, Oita-cho, Shimotsuga-gun, Tochigi Prefecture 2 of Hitachi Tochigi Electronics Co., Ltd.

Claims (2)

[Claims] 1. In a refrigeration cycle in which a compressor, a condenser, a capillary tube, and an evaporator are formed in a series closed circuit, only a partial section of a refrigerant return pipe from the evaporator to the compressor is parallel. In a refrigeration cycle in which a two-way valve, which is a pipe, is used to fully open and fully close one pipe and an auxiliary capillary tube is arranged to the other pipe, the compressor is stopped and the two-way valve is fully closed. A refrigerating cycle for a refrigerator, characterized in that the closing is synchronized, and when the compressor is started, the two-way valve is operated by delaying the full-open timing with respect to the start of the operation. 2. A non-return valve is disposed between a compressor suction pipe and a converging part of the pipe, in which the two-way valve and the auxiliary capillary tube are arranged, and the check valve is provided as a compressor. In a refrigeration cycle using a hermetic rotary in which the inside of the container is maintained at a high pressure, the stop of the compressor and the full closure of the two-way valve are synchronized, while the two-way operation is performed with respect to the operation of the compressor. The refrigerator refrigeration cycle according to claim 1, wherein the valve is operated by delaying the timing of full opening of the valve.