JPH03221761A - Refrigerant circuit for air conditioner - Google Patents

Abstract

PURPOSE:To prevent noise generation of refrigerant in a vaporizer at starting by forming a bypass valve of a valve body to open and close a passage between suction side and discharge side of a compressor, a first spring to energize the valve body to opening position at starting of an air conditioner, and a second spring made of shape memory alloy to energize the valve body to closing position. CONSTITUTION:When a compressor 1 starts operation, refrigerant flows into a bypass valve 5 from a high pressure side pipe 6, passes through cuts 17c 17b 17d of a valve body 17 in this order, and finally flows into a low pressure side pipe 7. In this while, the refrigerant is robbed of heat by the surroundings and its temperature remains low. As a result, a second spring 19 is in a thermally untransformed state, so that the bypass valve 5 is in opened state by a first spring 18. After operation continues for a certain period and the refrigerant temperature rises enough for thermal transformation, the second spring 19 extends to bring the valve body 17 into an intimate contact with a valve seat of a case 15 by the refrigerant force, so that the bypass valve 5 is closed. As a result, a delay time is given to the closing of a bypass circuit at the starting, and therefore refrigerant evaporation within a vaporizer can be restricted and noise generation can be also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a refrigerant circuit having a bypass valve between the suction side and the discharge side of a compressor of an air conditioner.

[Prior Art] FIGS. 4 and 5 are diagrams showing a refrigerant circuit of a conventional air conditioner disclosed in, for example, Japanese Utility Model Application Publication No. 59-9259.
FIG. 4 is a refrigerant circuit diagram, and FIG. 5 is a longitudinal sectional view of the bypass valve.

In the figure, (1) is the compressor, (2) is the condenser, (3) is the evaporator, (4) is the capillary tube, and (5) is the bypass valve.
Connected to the discharge side of the compressor (1) with a high pressure side pipe (6),
It is also connected to the suction side by a low pressure side pipe (7).

(8) is a valve seat provided in the flow path of the piping (61 (7));
(9) is a valve element that passes through the valve seat (8) and opens and closes the flow path, (lO) is a diaphragm that is connected to the valve element (9) and operates based on the pressure difference of the refrigerant, (Ill is a diaphragm (lO
) is a push spring that assists in the operation of the

The refrigerant circuit of a conventional air conditioner is configured as described above.
At the start of operation, the pressure on the suction side and the discharge side of the compressor are balanced, the two diaphragms (101 are in the state shown in Figure 5), and the valve body (9) opens the flow path of the valve seat (8). It is in a state of

When the compressor (1) starts, the pressure inside the high-pressure side pipe (6) becomes high, and the differential pressure between it and the low-pressure side pipe (7) increases through the diaphragm (
10) and the pressure spring (11), the diaphragm (lO) is pressed and operated, and the valve body (9)
) closes the flow path of the valve seat (8) and shifts to normal operation.

Furthermore, when the compressor (1) is stopped, the high-pressure side refrigerant flows into the low-pressure side through the capillary tube (4), and the differential pressure between the suction side and the discharge side of the compressor m becomes small. This is the diaphragm (lO)
When the pressure condition determined by the pressure spring [11] is reached, the diaphragm (lot) operates and the valve body (9) presses against the valve seat (8).
) to open the flow path. As a result, the pressures on the suction side and discharge side of the compressor (1) are balanced and the first compression is performed! '1(1) will be restarted smoothly.

[Problems to be Solved by the Invention] In the refrigerant circuit of the conventional air conditioner as described above, the diaphragm (1o) is used for the bypass valve (5).
There are problems in that it is necessary to consider the reliability of the diaphragm (IO), and the number of parts is large, resulting in high cost. Further, there is a problem that the pre-operation refrigerant may be trapped on the evaporator R3 (3) side, and the noise generated by evaporation during startup cannot be prevented.

This invention was made to solve the above problems, and it is possible to simplify the structure of the bypass valve, improve reliability and manufacturability, and prevent refrigerant noise from the evaporator at startup. The purpose of this invention is to provide a refrigerant circuit for an air conditioner.

[Means for Solving the Problems] A refrigerant circuit for an air conditioner according to the present invention includes a bypass valve, a valve body that opens and closes a flow path between the suction side and the discharge side of the compressor, and a valve body that opens and closes the flow path between the suction side and the discharge side of the compressor, and a valve body that opens and closes the flow path between the suction side and the discharge side of the compressor. The first valve body is biased to the open position.
and a second spring made of a shape memory alloy that urges the valve body to the closed position when the temperature of the refrigerant rises.

[Production ml] In this invention, since the valve body, the first spring, and the second spring made of shape memory alloy are used, the valve body at startup is connected to the suction side and the discharge side of the compressor by the first spring. However, when the compressor discharge gas temperature rises, the second spring operates and the valve body closes the flow path, giving a delay time for the bypass circuit to close, and preventing evaporation. Evaporation of the refrigerant inside the container is suppressed.

[Example] Figures 1 to 3 are diagrams showing an example of the present invention.
The figure is a vertical cross-sectional view of the bypass valve, the second figure is an explanatory diagram of the operation, and the third figure is a longitudinal cross-sectional view of the bypass valve.
The figure is a perspective view of the valve body, and parts similar to those of the conventional device are designated by the same reference numerals. Note that FIG. 4 is also used in this embodiment.

In the figure, (15) is a case that is connected to the low pressure side pipe (7) and also serves as a valve seat, (16) is a lid that is connected to the high pressure side pipe (6) and fixed to the case (15), and (17) is a case that is connected to the low pressure side pipe (7) and serves as a valve seat. Case(
15) is a valve body that is housed movably in the vertical direction in the figure, and has a tapered surface (17al) that comes into contact with the valve seat of the case (15), and has a notch f17bl~ that becomes a gas flow path.
(17dl is formed. (18) is the valve body (17dl).
) to the high pressure side pipe [6) II+,
(19) is made of shape memory alloy and the valve body (1
7) toward the low pressure side pipe (7).

In the refrigerant circuit of the air conditioner configured as described above, before the air conditioner is operated, the pressures on the suction side and the discharge side of the compressor (1) are balanced, and the valve body (17) is in the first position. Spring (
18) is located on the lid (16) side, and the high pressure side pipe (6) and low pressure side pipe (7) are connected to the notch + of the valve body (9).
17b) to (17dl). Also, before operation, the pressure inside the refrigerant circuit is balanced, but when the outdoor temperature is high, the evaporator (3) side of the indoor unit (not shown) The refrigerant is trapped in the

When operation is commanded and the compressor (1) is started, refrigerant flows into the bypass valve (5) from the high pressure side pipe (6). This inflowing refrigerant flows through the notch (17cl) of the valve body (17).
- = (17b) " (17d) and flows to the low pressure side pipe (7). At this time, since the operation has just started, the refrigerant loses heat to the surroundings and the temperature remains low. Therefore, the second spring (19) is in a state before thermal transformation, and the bypass valve (5) is in an open state due to the first spring (18).

When the operating time elapses from startup and the temperature of the refrigerant flowing into the bypass valve (5) reaches the thermal transformation temperature of the second spring (19), the second spring (19) expands and the temperature shown in FIG. As shown, the valve body (17) is brought into close contact with the valve seat of the case (15) by the force of the refrigerant, and the bypass valve (5) is closed. After that, the back pressure acting on the high pressure side of the valve body (9) causes the valve body (17
) is in stable contact with the valve seat, and normal operation is achieved.

In this way, from the start of operation until the valve body (17) is activated due to the temperature of the refrigerant, the suction side and discharge side of the compressor (1) are bypassed, and a sudden change on the suction side of the compressor CI+ is prevented. The pressure drop is alleviated. Therefore, rapid evaporation of the refrigerant that has been trapped in the evaporator (3) of the indoor unit is suppressed, and the noise generated from the evaporator (3) can be reduced, making the indoor unit low-noise.

When the air conditioner is stopped, the bypass valve (5) is in a closed state, as shown in FIG. 2. During operation, no high-temperature gas flows into the bypass valve (5), and due to heat conduction from the piping (6) [7], the shape memory alloy that is the material of the second spring (19) changes to a low-temperature martensitic phase. The temperature is lower than the temperature at which it undergoes metamorphosis. Therefore, the second spring (19) is in a state where it can be easily restored with a small force. When the air conditioner stops; the refrigerant on the high pressure side flows into the low pressure side through the capillary tube (4), and the pressure difference between the suction side and the discharge side of the compressor (1) balances the force pushing up the valve body (17). and the first
The valve body (17) is lifted up from the valve seat by the spring (18), the bypass valve (5) becomes open, and the pressure in the refrigerant circuit quickly reaches an equilibrium state.

[Effects of the Invention] As explained above, in this invention, the valve body of the bypass valve is set to a pressure of 1tfI by the first spring when the air conditioner is started.
The flow path between the suction side and the discharge side of the ET is biased to the open position, and when the compressor discharge gas temperature rises, the second spring made of shape memory alloy is biased to the closed position. Therefore, a delay time is given to blockage of the bypass circuit at startup, and evaporation of the refrigerant in the evaporator is suppressed, reducing noise. At the same time, reliability can be improved by simplifying the configuration of the bypass valve. effective.

[Brief explanation of drawings]

1 to 3 are diagrams showing an embodiment of the refrigerant circuit of an air conditioner according to the present invention, in which FIG. 1 is a vertical cross-sectional view of the bypass valve, FIG. Figure 3 is a perspective view of the valve body, Figures 4 and 5 are diagrams showing the refrigerant circuit of a conventional air conditioner, Figure 4 is a refrigerant circuit diagram, and Figure 5 is a longitudinal sectional view of the bypass valve. . In the diagram, (1) is the compressor, (2) is the condenser, (3)
is the evaporator, (5) is the bypass valve, (17) is the valve body, (
18) is the first spring, and (19) is the second spring. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] An evaporator is connected to the suction side of the compressor, a condenser is connected to the discharge side, and a refrigerant bypass line is provided between the suction side and the discharge side, and the pressure on the suction side and the discharge side are connected in the middle. A valve body that moves the bypass valve to a position where the flow path between the suction side and the discharge side is opened and a position where it is closed; a first spring that biases the valve body to the open position when the compressor is started; and a first spring made of a shape memory alloy that biases the valve body to the closed position when the discharge gas temperature of the compressor rises; A refrigerant circuit for an air conditioner, comprising a second spring.