JPS63263365A - Reversible expansion valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to an expansion valve used in a heat pump air-conditioning device or the like.

In the heat pump type air-conditioning system in the United States, heating and cooling are switched by reversing the flow direction of the refrigerant, but if the outdoor temperature is low during heating, frost may form on the outdoor heat exchanger. There is. Conventionally, the defrosting method in such cases is to switch the flow direction of the refrigerant using a four-way valve.
A method of supplying high-pressure, high-temperature refrigerant to an outdoor heat exchanger was often used. However, with this method, the indoor heat exchanger becomes an evaporator, which is inconvenient, so even during defrosting, the high-temperature refrigerant is supplied to the indoor heat exchanger without changing the flow direction of the refrigerant, and the high-temperature refrigerant is supplied to the outdoor heat exchanger. A method has been proposed to supply

Regarding such a method, as shown in FIG. 8, a part of the high-temperature, high-pressure refrigerant on the discharge side of the compressor C is introduced directly into front of the outdoor heat exchanger A via a bypass pipe equipped with a solenoid valve S3, etc. ,
Alternatively, as shown in Fig. 9, there is a method such as introducing the incompletely condensed warm refrigerant in the indoor heat exchanger B into the outdoor heat exchanger A via a solenoid valve St attached to the expansion valve E. Ta.

However, all of these methods require additional piping, electromagnetic valves, etc., and the control circuit becomes complicated, resulting in an increase in equipment costs.

Therefore, it is an object of the present invention to provide a control valve that has both the functions of a conventional expansion valve and a solenoid valve, and can also control the flow of refrigerant in both the forward and reverse directions. This is what I did.

[Structure of the invention]. The reversible expansion valve of the present invention, which can achieve the above-mentioned purpose of controlling the valve, is capable of continuously expanding the valve seat from the upper valve chamber side to the valve seat provided on the partition wall that partitions the upper valve chamber and the lower valve chamber. In an expansion valve equipped with a needle valve body that moves forward and backward, a pair of valve seats into which a main fluid passage opens are provided symmetrically on opposite side walls of the lower valve chamber, and are movable between the valve seats within the lower valve chamber. and a symmetrical valve body that can close any one of the openings, and a piston-shaped valve body holder that restricts the valve body from floating in a direction parallel to the valve seat, and the valve body is located in the lower valve chamber. means for urging the valve body holder in a direction to expand a back pressure space formed between the valve body holder and the partition wall; and a leakage passage connecting the lower valve chamber and the back pressure space, configured such that the center of the valve body is located on the common axis of the opening at the end of operation of the biasing means, The flow resistance is greater than the flow resistance when the needle valve is fully open, and the flow resistance is greater than the flow resistance when the needle valve is fully opened.The flow resistance is greater than the flow resistance when the needle valve is fully opened, and the flow resistance is greater than the flow resistance when the needle valve is fully opened.The flow resistance is greater than the flow resistance when the needle valve is fully opened.The flow resistance is greater than the flow resistance when the needle valve is fully opened.The flow resistance is greater than the flow resistance when the needle valve is fully opened.

In addition, it is preferable that the needle valve body in the valve of the present invention be moved back and forth in a stepless manner by incorporating a pulse motor or the like.

In such a reversible expansion valve of the present invention, the valve seat side space and back pressure space in the lower valve chamber partitioned by the piston-shaped valve body holder are, for example, leakage passages provided in the valve body holder itself or the valve body. They are connected by a leakage passage provided on the side or a passage such as a gap between the valve body holder and the side wall of the lower valve chamber, so that fluid compression does not occur when the valve body holder moves up and down within the lower valve chamber. It is necessary. And furthermore,
The flow resistance of this leak passage is greater than the flow resistance when the needle valve is fully open, and the pressure difference when fluid flows from the valve seat side space to the back pressure space through this leak passage causes the back pressure space to It is necessary that the force of a means for urging the valve body holder to expand, such as a spring, be set so as to overcome the force.

Additionally, check valves are provided in the sub passages that communicate the upper valve chamber and each of the main fluid passages, and the configuration is such that fluid from the main fluid passage cannot directly flow into the upper valve chamber. has been done.

In the reversible expansion valve of the present invention configured as described above, when fluid flows in from either one of the main fluid passages and the needle valve is closed, the pressure inside the lower valve chamber is uniformly increased, and the valve chamber is evenly pressurized. Since the body is pressed against the valve seat on the outflow side, fluid cannot escape.

Then, when the needle valve opens slightly, the fluid passes through the back pressure space, enters the upper valve chamber, passes through the secondary passage on the outflow side, and heads to the main fluid passage on the outflow side. Furthermore, when the needle valve opens, the flow rate increases, but when the needle valve approaches full opening, the pressure in the back pressure space decreases significantly, and as a result, the valve body holder moves in a direction that reduces the back pressure space. At this time, the valve element that has been press-fitted to the outflow side valve seat is displaced from the main fluid passage opening by the valve element holder, and the main fluid passage is opened.

In this way, the reversible expansion valve of the present invention has a needle valve with Pyro 7.
It operates as a gate valve and has a symmetrical structure.
It works exactly the same even if the direction of flow is reversed.

cusp stand An example of the reversible expansion valve of the present invention is shown in FIG.

Reference numeral 1 denotes a valve body, an upper lid 11 is attached to the upper part of the valve body, and an upper valve chamber 21 is formed between a partition wall 2 attached inside and an upper M11. A valve seat 22 is provided on the partition wall 2, and a needle valve body 3 is driven by a motor 9.
It is designed to open and close with.

9 is an electric actuator attached to the upper part of the valve body 1. Reference numeral 91 denotes a male threaded cylinder installed in the upper lid 11 so that the needle valve body 3 can pass therethrough, and 92 denotes a male threaded cylinder 9.
A rotor is rotatably screwed onto the rotor. 94 is a stator coil attached to the outside of the shield tube 93. The rotor 92 and the upper end 31 of the needle valve body 3 are rotatably connected, and as the rotor 92 rotates, it moves in the axial direction along the male threaded cylinder 91. This axial movement is caused by the spring 95. This is transmitted to the needle valve body 3 without play, and the needle valve body 3 advances and retreats in proportion to the amount of rotation of the rotor 92.

Valve seats 4a and 4b are provided in the lower part of the valve body 1, facing the valve chamber side wall surface, through which the main fluid passages a and b open. Reference numeral 5 denotes a spherical valve body, which can close any one opening of the valve seats 4a, 4b. Reference numeral 6 denotes a piston-shaped valve body holder that can slide up and down within the valve chamber, and a guide frame 61 is provided at the bottom of the body, which allows the valve body 5 to freely move only between the valve seats 4a and 4b. It is formed.

Therefore, the movement range of the valve body 5 is restricted within the guide frame 61 and cannot move in the direction parallel to the valve seat surface.The valve body holder 6 has a back pressure chamber formed between it and the partition wall 2. 13 and the lower valve chamber 12 is provided with a narrow leakage passage 62. 7 is a spring provided in the back pressure chamber 13, and the valve body holder 6
When the valve body 5 is pushed and comes into contact with the bottom surface of the valve chamber, the center of the valve body 5 is positioned on the common axis of the opening on the valve seat.

Further, 1a is a sub passage bored in the valve main body l so as to communicate the upper valve chamber 21 and the main fluid passage a, and 8a is a check valve provided in the sub passage la, and 8a is a check valve provided in the sub passage la. This prevents the flow from a toward the upper valve chamber 21. (2) b and 8b are a sub passage and a check valve, respectively, which similarly allow only flow from the upper valve chamber 21 toward the main fluid passage.

An example in which the reversible expansion valve configured as described above is incorporated into a heating/cooling air conditioning circuit is shown in Figure 2 (0), where A is an outdoor heat exchanger, B is an indoor heat exchanger, and C is a compressor. , D is a four-way switching valve, and EV is a reversible expansion valve of the present invention.

The operation of the reversible expansion valve of the present invention in the air conditioning circuit of FIG. 2 will be explained with reference to FIGS. 3 to 6.

FIG. 3 shows the state during normal cooling operation. The refrigerant flowing from the outdoor heat exchanger A through the main fluid passage a enters the lower valve chamber 12 and also enters the back pressure chamber 13 through the leakage passage 62, so that the upper and lower surfaces of the valve body holder 6 and The pressures are balanced, the valve element holder 6 is pushed down by the force of the spring 7, and the valve element 5 maintains the position where the opening of the valve seat 4b is closed. Therefore, the refrigerant in the back pressure chamber 13 enters the upper valve chamber 21 while its flow rate is restricted by the needle valve body 3, and heads to the main fluid passage via the sub passage 1b without being blocked by the check valve 8b. The refrigerant in the sub passage la is checked by the check valve 8a.
It is prevented from entering the upper valve chamber 21.

FIG. 4 shows a situation where it is necessary to increase the supply of refrigerant, such as at the start of cooling operation. The pressure of the refrigerant from the outdoor heat exchanger A is applied to the lower valve chamber 12 and the back pressure chamber 13.
When the opening degree of the needle valve body 3 is increased while the valve is in the lower valve chamber, the pressure in the back pressure chamber 13 decreases due to the flow resistance of the leak passage 62, and the pressure between the back pressure chamber 13 and the lower valve chamber 12 decreases. When the differential pressure exceeds the pressing force of the spring 7, the valve element holder 6 is pushed up, and the valve element 5 is therefore displaced from the valve seat 4b.

At this time, the refrigerant flows out from the main fluid passage a through the lower valve chamber 12 and into the main fluid passage, and a large amount of refrigerant can be supplied to the indoor heat exchanger B.

FIG. 5 shows the state during normal heating operation. At this time, the refrigerant flows from the indoor heat exchanger B through the main fluid passage, and flows through the lower valve chamber 12, the leakage passage 62, the back pressure chamber 13, the opening of the valve seat 22, the upper valve chamber 21, the sub passage 1a, and the main fluid passage. It passes through the body passage a in order and heads for the outdoor heat exchanger A. This flow state is completely symmetrical to that during normal cooling operation in FIG.

FIG. 6 shows a state in which the outdoor heat exchanger is defrosted during heating operation. At this time, similar to the operation in FIG. 4, by increasing the opening degree of the needle valve body 3, the valve body holder 6 is pushed up, the valve body 5 is displaced, and the main fluid passage a is opened. Therefore, the incompletely condensed high-temperature refrigerant in the indoor heat exchanger B flows directly into the outdoor heat exchanger A, and defrosting is performed.

The flow rate characteristics of the reversible expansion valve of the present invention are as shown in FIG. 7, and can be controlled in the same manner whether the direction of the fluid is forward or reverse.

〔Effect of the invention〕

The reversible expansion valve of the present invention is capable of precise flow control at low flow rates and also has the ability to open and close large flow rates, making the refrigeration circuit complicated in order to defrost the outdoor heat exchanger during heating. Not only can such disadvantages be avoided, but also rapid and high-output operation is possible by supplying a large amount of refrigerant at the start of operation.

These valve characteristics are the same regardless of the flow direction, so there is no need to consider the direction when assembling into equipment, and there is an advantage that the same rapid operation is possible for both cooling and heating. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an example of the reversible expansion valve of the present invention, Fig. 2 is an example of a cooling/heating refrigeration circuit using the reversible expansion valve of the present invention, and Figs. 3 to 6 are operations of the reversible expansion valve of the present invention. 7 is a graph showing an example of the flow rate characteristics of the reversible expansion valve of the present invention, and FIGS. 8 and 9 are examples of a conventional cooling/heating refrigeration circuit. 1... Valve body, a, b... Main fluid passage, la, lb
...Sub-passage, 11...Upper lid, 12...Lower valve chamber,
13... Back pressure chamber, 2... Partition wall, 21... Upper valve chamber, 22... Valve seat, 3... Needle valve body, 4a, 4
b... Valve seat, 5... Valve body, 6... Valve body holder, 61... Guide frame, 62... Leak passage, 7...
Spring, 8a, 8b... Check valve, 9... Actuator, 91... Male thread cylinder, 92... Rotor,
95: Spring. Patent Applicant: Saginomiya Seisakusho Co., Ltd. No. 1, Figure 2, Figure 4, Figure 3, Figure 6, Figure 5, Figure 8

Claims (1)

[Claims] In an expansion valve equipped with a needle valve body that moves steplessly forward and backward from the upper valve chamber side with respect to a valve seat provided in a partition wall that partitions an upper valve chamber and a lower valve chamber, a pair of valve bodies each having a main fluid passage open therein are provided. Valve seats are provided symmetrically on opposite side walls of the lower valve chamber, and a symmetrically shaped valve body that is movable between the valve seats and can close any one of the openings is provided in the lower valve chamber, and the valve body. a piston-shaped valve body holder that restricts free movement in a direction parallel to the valve seat, and is fitted so as to be vertically slidable within the lower valve chamber, and the valve body holder and a means for biasing the valve body holder in a direction to expand the back pressure space formed between the partition wall and the partition wall, and at the end of the operation of the biasing means, the center of the valve body is located in common with the opening. A leakage passage configured to be located on the axis and communicating between the lower valve chamber and the back pressure space, the flow resistance of which is greater than the flow resistance when the needle valve is fully open, and a leakage passage from the upper valve chamber. A reversible expansion valve that is provided with sub passages that allow flow only toward each of the main fluid passages.