JPH0473054B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an air conditioner, specifically, an air conditioner equipped with a compressor, an indoor heat exchanger, an expansion mechanism, and an outdoor heat exchanger, and capable of heating operation. Relating to a harmonizing device.

(Prior art) Generally, in this type of air conditioner, the suction pressure temporarily drops dramatically when heating operation starts.
In the outdoor heat exchanger, residual moisture remaining on the heat exchanger freezes, and this ice becomes the nucleus of frost, promoting the growth of frost.As a result, problems such as shortening the defrost interval and heating The problem was that the start of operation was slow.

Therefore, as a conventional means to solve these problems, for example, at the start of heating operation, intermediate pressure gas refrigerant in the middle of the compression stroke of the compressor is bypassed to the suction side to prevent the suction pressure from decreasing. This was proposed in Publication No. 18341/1983.

To explain this based on FIG. 4, in the cylinder 50 of a reciprocating type compressor,
A control passage 55 that forms a bypass hole 53 that communicates the cylinder chamber 51 and the suction chamber 52, is provided with a valve body 54 that closes the bypass hole 53, and introduces high control pressure to the back side of the valve body 54. The control passage 55 is provided with an on-off valve 56 that electrically controls opening and closing of the passage 55 based on the output of a detector (not shown) that detects the discharge gas temperature.

Furthermore, 57 is a bias spring.

Thus, since the temperature of the discharged gas is low at the start of the heating operation, the on-off valve 56 is closed and the action of high pressure on the back surface of the valve body 54 is prevented.
The valve body 54 is pushed up by the bias spring 57, and the bypass hole 53 is opened. Thus, the intermediate pressure refrigerant in the cylinder chamber 51 in the middle of the compression stroke bypasses the suction chamber 52, and the suction pressure becomes extreme. This is to prevent any significant decline.

On the other hand, when the discharge gas temperature rises in the process of this bypass operation, the detection body detects this temperature rise, opens the on-off valve 56, applies high pressure to the back surface of the valve body 54, and This closes the bypass hole 53 and starts normal heating operation.

(Problems to be Solved by the Invention) However, in the above conventional system, in order to bypass the compressed refrigerant gas to the suction side at the start of heating operation, the discharge gas temperature is detected and the opening/closing valve 56 is electrically operated. Since a means for controlling opening and closing is required, the structure is complicated and manufacturing costs are high.

Therefore, an object of the present invention is to devise a passage for bypassing compressed refrigerant gas to the suction side, and in particular, to devise means for opening and closing the passage so as to open and close the passage by directly sensing the discharge gas temperature. Although the structure is simple and does not require electrical control, the compressed refrigerant gas can be bypassed to the suction side only when heating operation is started.

(Means for Solving the Problems) Compressor 4, indoor heat exchanger 3, expansion mechanism 2, outdoor heat exchanger 1, four-way switching In an air conditioner equipped with a valve 5 and capable of heating and cooling operation, one end side is connected to the four-way switching valve 5, and the other end side is connected to the indoor heat exchanger 3, and serves as a low pressure gas pipe during cooling operation, and serves as a low pressure gas pipe during heating operation. The heat exchangers 1 and 3 and the expansion mechanism 2 are installed between the gas pipe 6, which becomes a high-pressure gas pipe, and the suction gas pipe 42, which is connected between the compressor 4 and the four-way switching valve 5. A bypass pipe 7 is provided, and a valve body 82 is provided at the inlet portion of the bypass pipe 7 on the side of the gas pipe 6 to open and close the bypass pipe 7. When the discharge gas temperature is lower than a predetermined temperature, the valve body 82
The temperature-sensitive valve 8 is provided with an operating body 87 that opens the valve body 82 and closes the valve body 82 when the temperature exceeds the predetermined temperature.

(Function) During heating operation, even if the compressor 4 is driven, the discharge gas temperature does not rise immediately and remains at a low temperature, so the bypass pipe 7 on the gas pipe 6 side through which low-temperature discharge gas flows. The temperature-sensitive valve 8 provided at the inlet portion is maintained at a low temperature lower than the predetermined temperature, and therefore the valve 8 is connected to the bypass pipe 7.
Therefore, the discharge gas is bypassed through the bypass pipe 7 to the suction gas pipe 41 which is the suction side of the compressor 4. This makes it possible to prevent an extreme drop in suction pressure at the time of startup, and also to improve the start-up of heating operation.

Furthermore, when the discharge gas temperature rises due to the operation of the compressor 4 and reaches the predetermined temperature or higher, the temperature-sensitive valve 8 operates to close the bypass pipe 7, and normal heating operation can be started.

During cooling operation, low-temperature suction gas lower than a predetermined temperature flows through the gas pipe 6 , the operating body 87 contracts and the valve body 82 is operated, and the bypass pipe 7
The suction gas refrigerant flowing through the gas pipe 6 is divided into the bypass pipe 7 side and the four-way switching valve 5 side by the temperature-sensitive valve 8,
Both of them flow out into the suction gas pipe 42.

(Example) What is shown in FIG. 1 is a heat pump type air conditioner equipped with a stationary vane type compressor and capable of performing cooling operation and heating operation.

1 is an outdoor heat exchanger, 2 is a capillary reach tube that functions as an expansion mechanism, and 3 is an indoor heat exchanger. These devices and a compressor 4 are connected via a four-way selector valve 5. Thus, by placing the four-way switching valve 5 in the switching position as shown by the solid line,
A cooling operation can be performed in which the refrigerant discharged from the compressor 4 is circulated as shown by the solid line arrow, while the discharge gas discharged from the compressor 4 can be controlled by placing the four-way switching valve 5 in the switching position as shown by the broken line. It is possible to perform heating operation by circulating as shown by the broken line arrow.

Therefore, in the air conditioner configured as described above, one end side is connected to the four-way switching valve 5, and
A gas pipe 6 whose other end is connected to the indoor heat exchanger 3 and serves as a low-pressure gas pipe during cooling operation and a high-pressure gas pipe during heating operation, is connected between the compressor 4 and the four-way switching valve 5. A bypass pipe 7 that bypasses each of the heat exchangers 1 and 3 and the expansion mechanism 2 is interposed between the suction gas pipe 42 and the intake gas pipe 42. A temperature-sensitive valve 8 is provided to open and close the bypass pipe 7.

The specific structure of this temperature-sensitive valve 8 will be explained below based on FIGS. 2 and 3.

This valve 8 has a valve hole 83 in which a valve body 82 is slidably guided in a substantially cylindrical housing 81, and a portion 6a of the gas pipe 6 on the four-way switching valve 5 side at one end of the housing 81. A first entrance/exit 84 connecting the housing 81 is formed.
A second inlet/outlet 85 for connecting the bypass pipe 7 is formed at the other end, and a second inlet/outlet 85 is formed at the side of the housing 81 to connect the indoor heat exchanger 3 side portion 6 of the gas pipe 6.
A third entrance/exit 86 is formed to connect b.

Furthermore, the second entrance/exit 8 of the housing 81
A shaft-shaped valve portion 82c has a truncated cone-shaped seat surface 82b at its tip that forms a seating surface 85a on the seating surface 85a.
The valve hole 8 is provided integrally with the valve portion 82c.
A disc-shaped guide portion 82d that slides along the inner surface of 3.
It is formed from.

Further, as shown in FIG. 3, the guide portion 82d is provided with four refrigerant flow grooves 82e in the radial direction that allow the refrigerant to flow through the guide portion 82d.

Furthermore, the guide portion 82 in the valve hole 83
A coil-shaped operating body 87 made of a shape memory alloy is interposed between the guide portion 82d and the end face on the side of the first entrance/exit 84, and between the guide portion 82d and the inner surface on the side of the second entrance/exit 85. A bias spring 88 that presses the valve body 82 toward the first entrance/exit port 84 is interposed.

The operating body 87 has a predetermined temperature (for example, 50° C.)
When the valve body 82 is lower, it contracts in the sliding direction of the valve body 82, and as the valve body 82 contracts, the pressure of the bias spring 88 causes the valve body 82 to contract.
2 moves to the right and acts to open the bypass pipe 7, and extends in the opposite direction when the temperature exceeds a predetermined temperature to move the valve body 82 to the left against the pressing force of the bias spring 88, thereby opening the bypass pipe 7. It is designed to act as if it were closing the door.

Next, the operation of the air conditioner configured as above will be explained.

First, the heating operation will be explained.

When the compressor 4 is driven, the refrigerant circulates as shown by the broken line arrow in FIG. is contracted to move the valve body 82 to the right, which operates to open the bypass pipe 7.

Therefore, the gas discharged from the compressor 4 is
While flowing out to the indoor heat exchanger 3, a part of it is branched to the bypass pipe 7 and flows out to the suction gas pipe 42.

As a result, an extreme drop in the suction pressure of the compressor 4 is prevented, and residual moisture in the outdoor heat exchanger 1 is prevented from freezing.

In addition, the start-up of heating operation is also improved.

Then, by continuing the operation with the bypass pipe 7 open, when the discharge gas temperature reaches the predetermined temperature, the operating body 87 of the temperature-sensitive valve 8 extends and closes the valve body 82. It moves to the right and operates as if closing the bypass pipe 7. In this way, normal heating operation is started.

Next, cooling operation will be explained.

In this case, when the compressor 4 is operated, the refrigerant circulates as shown by the solid line arrow in FIG. 1, and suction gas at a low temperature far lower than the predetermined temperature always flows through the gas pipe 6. Therefore, the temperature sensitive valve 8 is also maintained at a temperature lower than the predetermined temperature. Therefore, the operating body 87 contracts and moves the valve body 82 to the right to open the bypass pipe 7. Therefore, the suction gas refrigerant flowing through the gas pipe 6 is transferred to the temperature-sensitive valve 8. And the bypass pipe 7
and a portion 6a of the gas pipe 6 on the side of the four-way switching valve 5, and both flow into the suction gas pipe 42.

Note that the present invention is of course applicable not only to heat pump type air conditioners but also to air conditioners that perform only normal heating operation. In this case, the bypass pipe 7 may be provided so as to connect the discharge gas pipe that connects the discharge side of the compressor 4 to the indoor heat exchanger 3 and the suction gas pipe 42 .

(Effects of the Invention) As described above, according to the present invention, one end side is connected to the four-way switching valve 5, and the other end side is connected to the indoor heat exchanger 3, and becomes a low pressure gas pipe during cooling operation, and becomes a low pressure gas pipe during heating operation. The heat exchangers 1 and 3 and the expansion mechanism 2 are placed between the gas pipe 6, which is a high-pressure gas pipe, and the suction gas pipe 42, which is connected between the compressor 4 and the four-way switching valve 5. A bypass pipe 7 is provided at the inlet of the bypass pipe 7 on the side of the gas pipe 6 to open and close the bypass pipe 7, and a valve element 82 made of a shape memory alloy and temperature-sensitive to the discharged gas is provided. When the discharge gas temperature is lower than a predetermined temperature, the valve body 82
Since the temperature-sensitive valve 8 is provided with an operating body 87 that opens the valve body 82 and closes the valve body 82 when the temperature exceeds the predetermined temperature, it is possible to directly sense the high-pressure gas consisting of the low-temperature discharge gas at the time of starting the heating operation. The temperature-sensitive valve 8 that heats operates to open the bypass pipe 7, and the discharge gas can be bypassed to the suction side of the compressor 4 through the bypass pipe 7, and the suction gas at the start of heating operation can be bypassed to the suction side of the compressor 4. An extreme drop in pressure can be prevented.

Therefore, there is no need to provide a control means for electrically controlling the bypass of compressed refrigerant gas as in the past, and although the configuration is extremely simple, compressed refrigerant gas can be bypassed to the suction side at the start of heating operation. It is possible to prevent an extreme drop in the suction pressure, thereby preventing a shortening of the defrost interval time due to freezing in the outdoor heat exchanger 1 at the time of startup, and also making it possible to start the heating operation smoothly.

Further, during cooling operation, the temperature of the suction gas refrigerant flowing through the gas pipe 6 is low, and the temperature-sensitive valve 8 operates to open the bypass pipe 7, so that the suction gas refrigerant flowing through the gas pipe 6 is At the temperature-sensitive valve 8, the flow is divided so as to pass through the bypass pipe 7 and the four-way switching valve 5, but it merges and flows out into the suction gas pipe 42. Despite the provision, cooling operation can be performed as usual without any trouble.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of embodiments of the present invention, and the first
The figure is a refrigerant circuit diagram, Figure 2 is a vertical cross-sectional view of an embodiment of the temperature-sensitive valve, Figure 3 is a cross-sectional view of Figure 2, and Figure 4 is a cross-sectional view of the temperature-sensitive valve.
The figure is an explanatory diagram of a conventional example. 1... Outdoor heat exchanger, 2... Expansion mechanism, 3...
... Indoor heat exchanger, 4 ... Compressor, 6 ... Gas pipe (discharge pipe), 7 ... Bypass pipe, 8 ... Temperature-sensitive valve, 82 ... Valve body, 87 ... Operating body.

Claims (1)

[Claims] 1. In an air conditioner equipped with a compressor 4, an indoor heat exchanger 3, an expansion mechanism 2, an outdoor heat exchanger 1, and a four-way switching valve 5, and capable of heating and cooling operation, one end side is connected to the four-way switching valve 5. , and a gas pipe 6 whose other end is connected to the indoor heat exchanger 3 and serves as a low-pressure gas pipe during cooling operation and serves as a high-pressure gas pipe during heating operation;
Each of the heat exchangers 1 and 3 is connected between the compressor 4 and the suction gas pipe 42 connected between the four-way switching valve 5.
A bypass pipe 7 that bypasses the expansion mechanism 2 is interposed, and a valve body 82 for opening and closing the bypass pipe 7 is provided at the inlet portion of the bypass pipe 7 on the gas pipe 6 side.
and an operation in which the valve body 82 is made of a shape memory alloy and senses the temperature of the discharged gas to open the valve body 82 when the temperature of the discharged gas is lower than a predetermined temperature, and to close the valve body 82 when the temperature exceeds the predetermined temperature. An air conditioner characterized by being provided with a temperature-sensitive valve 8 consisting of a body 87.