JP7429602B2 - Thermostatic expansion valve and refrigeration cycle system - Google Patents

Description

The present invention is a thermostatic expansion device used in a refrigeration cycle system that adjusts the superheat setting value by adjusting the biasing force of a biasing spring that biases a valve element in the valve closing direction on the axis of a valve port. Related to valves and refrigeration cycle systems.

Conventionally, as this type of thermostatic expansion valve, there is one disclosed in, for example, Japanese Unexamined Patent Publication No. 2012-229885 (Patent Document 1). The temperature-type expansion valve (temperature expansion valve) of Patent Document 1 is provided with an O-ring for sealing an adjustment screw that adjusts the superheat setting value, and a seal cap (lid member 5) and a sealing member ( 4), the inside of the thermostatic expansion valve is airtightly separated from the atmosphere.

JP2012-229885A

Technologies such as Patent Document 1 use O-rings and sealing members, but in general, O-rings and sealing members completely eliminate the possibility of slight leakage of refrigerant from the valve body. The problem is that I can't. Furthermore, if refrigerant leaks from the valve body to the outside, the amount of refrigerant charged in the refrigeration cycle system provided with the thermostatic expansion valve will decrease, which is undesirable because the expected capacity will not be obtained. Furthermore, in order to reduce CO ₂ (carbon dioxide) emissions, a shift is being made from refrigerants with high GWP (global warming potential) to alternative refrigerants with low GWP, and flammable refrigerants are sometimes used. However, when using a flammable refrigerant, it is necessary to particularly suppress leakage of the refrigerant to the outside due to its flammable nature.

An object of the present invention is to eliminate external leakage of refrigerant from the valve body in a thermostatic expansion valve that adjusts the superheat setting value by adjusting the biasing force of a biasing spring that biases the valve body. shall be.

The thermostatic expansion valve of the present invention is connected via piping between the condenser and evaporator of a refrigeration cycle system, and adjusts the biasing force of a biasing spring that biases the valve body in the valve closing direction on the axis of the valve port. In the thermostatic expansion valve, the temperature-type expansion valve is configured to adjust the superheat degree setting value by adjusting the superheat degree setting value, and the valve body includes a valve body in which the valve body is built in the valve chamber, and an adjustment spindle that expands and contracts the biasing spring in the axial direction. an adjustment section facing the inside of the valve body, the interior of the valve body and the adjustment chamber of the adjustment section are partitioned off by a flexible airtight member, and one side of the airtight member The other side of the airtight member is joined to the valve body, and the other side is disposed on the axis of the adjustment spindle between the inside of the valve body and the adjustment spindle , and the other side of the airtight member is connected to the adjustment part of the adjustment part. It is characterized by being provided on the spindle side .

In this case, it is preferable that the other side of the airtight member is provided on the adjustment spindle side of the adjustment section.

Further, it is preferable that the airtight member is a thermostatic expansion valve characterized in that it is a bellows.

The refrigeration cycle system of the present invention is a refrigeration cycle system including a compressor, a condenser, an evaporator, and a throttle device, and the temperature-type expansion valve is used as the throttle device. shall be.

According to the thermostatic expansion valve of the present invention, the inside of the valve body and the adjustment chamber of the adjustment section are partitioned off by a flexible airtight member, and one side of this airtight member is joined to the valve body. Therefore, external leakage of refrigerant from the valve body can be eliminated. Further, since the airtight member has flexibility, the superheat degree setting value can be easily adjusted by transmitting the operation of the adjustment spindle to the biasing spring.

1 is a partial vertical sectional view of a thermostatic expansion valve according to a first embodiment of the present invention. FIG. 2 is a sectional view taken along the line BB of the valve housing and actuating rod portion of FIG. 1; FIG. 7 is a partial vertical cross-sectional view of a thermostatic expansion valve according to a second embodiment of the present invention. 1 is a schematic configuration diagram of a refrigeration cycle system according to an embodiment of the present invention.

Next, embodiments of the thermostatic expansion valve and refrigeration cycle system of the present invention will be described with reference to the drawings. FIG. 1 is a partial longitudinal sectional view of a thermostatic expansion valve according to the first embodiment, FIG. 2 is a sectional view taken along the line BB of the valve housing and actuating rod portion of FIG. 1, and FIG. 3 is a thermostatic expansion valve according to the second embodiment. FIG. 3 is a partial vertical cross-sectional view of the expansion valve. Note that the concept of "up and down" in the following explanation corresponds to the up and down in the drawings of FIGS. It corresponds to the moving direction of the valve body 2. The thermostatic expansion valve 100 of this embodiment includes a valve main body 10 having a valve housing 1 as a skeleton, an adjusting section 20 fixed to the lower part of the valve main body 10, and a capillary tube 30a connected to the valve main body 10. It is composed of a temperature sensing tube 30 connected with

In the valve body 10, the valve housing 1 is made of metal, and a primary joint 11 through which fluid (refrigerant) flows in and a secondary joint 12 through which fluid flows out are attached to the valve housing 1. The primary joint 11 and the secondary joint 12 are parallel to each other at different levels in the direction perpendicular to the axis X, and between the primary joint 11 and the secondary joint 12, there is a valve port 13 and a valve chamber 1A. is formed. In this embodiment, the primary joint 11 and the secondary joint 12 are formed perpendicular to the axis X, but either one, or both of the primary joint 11 and the secondary joint 12 It may be formed obliquely with respect to the axis X. The valve port 13 and the valve chamber 1A have a cylindrical shape centered on the axis X, and the valve port 13 communicates the primary port 11a, which communicates with the primary joint 11, with the valve chamber 1A. Further, the valve chamber 1A communicates with the secondary joint 12 via the secondary port 12a.

In the valve chamber 1A, a valve body 2 facing the valve port 13 is disposed on the valve port 13 side. The valve body 2 includes a conical needle portion 21 whose end portion can be brought close to or separated from the valve port 13, and a flange portion 22 on the outer periphery of the needle portion 21. Further, a bellows 5 as an "airtight member" is installed in the valve chamber 1A as described later, and the bellows 5 is formed in a bottomed shape having an integral end plate 51. A ball 23 is disposed between the end plate 51 at the upper end (on the other side) of the bellows 5 and the valve body 2. Further, a stopper 53 is housed inside the bellows 5 in contact with the end plate 51. Further, a biasing spring 24 is disposed inside the bellows 5, and this biasing spring 24 is compressed between the stopper 53 and the spring receiver 25. The spring receiver 25 is in contact with a spherical convex portion 43 on an adjustment spindle 42 of the adjustment section 20, which will be described later. The valve body 2 is urged in the valve closing direction by the urging spring 24. The length of the bellows 5 is set to such a length that it is in a contracted state when installed in the valve chamber 1A. This makes it difficult for the bellows 5 to expand or contract due to pressure fluctuations in the valve chamber 1A, which will be described later.

A diaphragm device 3 is attached to the upper part of the valve housing 1 . The diaphragm device 3 has a case body composed of an upper cover 31 and a lower cover 32, and by screwing the lower part of the lower cover 32 to the upper end of the valve housing 1, the diaphragm device 3 is aligned with the axis of the valve housing 1. It is attached to the upper end of the X. In this embodiment, the lower cover 32 is attached to the upper end of the valve housing 1 by screwing, but the lower cover 32 may be attached to the valve housing 1 by suitable means such as brazing or welding. Further, a diaphragm 33 is provided between the upper lid 31 and the lower lid 32, and the inside of the case body consisting of the upper lid 31 and the lower lid 32 is partitioned by the diaphragm 33 into a pressure receiving chamber 31A and a pressure equalizing chamber 32A. . Further, as shown in FIG. 2, a pressure equalizing passage 16 is formed in the valve housing 1 in the direction of the axis X, and the pressure equalizing chamber 32A is communicated with the valve chamber 1A through this pressure equalizing passage 16. Valve chamber pressure is introduced into this pressure equalization chamber 32A via the pressure equalization path 16 (internal pressure equalization type).

The pressure receiving chamber 31A is connected to the temperature sensing cylinder 30 by a capillary tube 30a. Thereby, the internal pressure of the pressure receiving chamber 31A changes according to the temperature sensed by the temperature sensing tube 30. Then, the diaphragm 33 is displaced according to the pressure difference between the pressure receiving chamber 31A and the pressure equalizing chamber 32A, and this displacement is transmitted to the valve body 2 (its flange portion 22) by the stopper 34 and the actuating rod 35. Note that three actuating rods 35 are provided around the axis X, and each abuts on the flange portion 22 of the valve body 2, but the number of actuating rods 35 is not limited to this. That is, two may be provided around the axis X, or one may be provided coaxially with the axis.

The valve body 1 has a valve housing 1 and an adjustment part housing 41, which will be described later, and an adjustment part 20 is provided in the valve chamber 1A and the lower part of the valve housing 1. The adjustment section 20 is constructed of an adjustment section housing 41 having an adjustment chamber 41A on the valve housing 1 side. The adjustment chamber 1A is defined inside the valve body 1 by an airtight member (bellows 5), which will be described later, and accommodates the adjustment spindle 42 therein. The adjustment portion housing 41 is fixed to the valve housing 1 by screwing the open end of the adjustment chamber 41A to the lower end of the valve housing 1. A female threaded portion 41a is formed in the center of the adjustment portion housing 41, and an adjustment spindle 42 having a male threaded portion 42a on the outer periphery is screwed into this female threaded portion 41a. A spherical protrusion 43 is integrally formed at the end of the adjustment spindle 42 on the adjustment chamber 41A side, and the spring receiver 25 is fitted in contact with the spherical protrusion 43. Further, a cutout 42b is formed at the lower end of the adjustment spindle 42, into which a wrench is inserted when rotating the adjustment spindle 42. Note that the lower part of the adjustment unit housing 41 and the lower part of the adjustment spindle 42 are covered by a lid member 44. The adjustment part housing 41 is provided with a seal member S, and the space between the adjustment part housing 41 and the lid member 44 is sealed. As a result, even if the frost adhering to the surfaces of the valve housing 1 and the adjustment part housing 41 melts, the frost generated from the space between the male threaded part 42a of the adjustment spindle 42 and the female threaded part 41a of the adjustment part housing 41 is melted. This prevents moisture from entering the adjustment chamber 41A. As the material of the sealing member S, an appropriate material such as PTFE (polytetrafluoroethylene) resin, rubber such as NBR, metal, etc. can be used. Note that the volume of the adjustment chamber 41A will also change due to the expansion and contraction of the bellows 5 as the valve body 2 moves in the axial direction. The influence of changes in the internal pressure within the adjustment chamber 41A due to changes in the volume of the chamber 41A is suppressed. Furthermore, by providing a communication hole in the adjustment unit housing 41 that communicates the space accommodating the lid member 44 and the space accommodating the bellows 5 in the adjustment unit housing 41, the volume of the adjustment chamber 41A can be further increased. Furthermore, the influence of changes in the volume of the adjustment chamber 41A due to expansion and contraction of the bellows 5 can be suppressed. Increasing the volume of the adjustment chamber 41A is particularly suitable when the amount of movement of the valve body 2 in the axial direction is relatively large or when the effective pressure receiving diameter of the bellows 5 is large.

With the above configuration, this thermostatic expansion valve 100 operates as follows. As will be explained later in the refrigeration cycle system, in this thermostatic expansion valve 100, the outlet side piping of the condenser is connected to the primary side joint 11, and the inlet side piping of the evaporator is connected to the secondary side joint 12. and installed in the refrigeration cycle system. Further, the temperature sensing tube 30 is attached to the outlet side piping of the evaporator. When the temperature of the outlet side piping of the evaporator (sensed temperature of the temperature sensing cylinder 30) increases, the valve element 2 operates to open the valve port 13 due to the displacement of the diaphragm 33 of the diaphragm device 3, and the temperature of the outlet side piping increases. When the value becomes low, the valve port 13 is closed. Further, when the pressure inside the valve chamber 1A (evaporation pressure in the evaporator) becomes low, the valve body 2 operates to open the valve port 13, and when the pressure within the valve chamber 1A (evaporation pressure) increases, the valve body 2 operates to open the valve port 13. It operates to close port 13. In this way, the valve port 13 allows refrigerant to flow from the condenser to the evaporator in accordance with the differential pressure between the pressure in the pressure receiving chamber 31A and the pressure in the valve chamber 1A (evaporation pressure) due to the temperature sensed by the temperature sensing cylinder 30. control the degree of superheating of the refrigeration cycle system.

By rotating the adjusting spindle 42 in the adjusting section 20 of the thermostatic expansion valve 100, the adjusting spindle 42 is displaced in the direction of the axis X with respect to the adjusting section housing 41. As a result, the amount of expansion and contraction of the biasing spring 24 in the axis X direction changes, and the biasing force of the valve body 2 in the valve closing direction changes. Therefore, by adjusting the screwing amount of the adjusting spindle 42, the pressing force against the diaphragm 33 by the valve body 2 and the actuating rod 35 can be changed. In this way, the biasing force of the biasing spring 24 can be adjusted, so that the pressure at which the valve port 13 starts to open, that is, the degree of superheat The setting pressure can be adjusted.

Here, the bellows 5 has a rim portion 5a on the opposite end (one side) of the end plate 51 fixed to the inside of a ring-shaped fixture 52 by welding or the like, and this fixture 52 is attached to the valve housing. The valve housing 1 is fitted into an annular rim portion 1a at the lower end of the valve housing 1, and is fixed to the valve housing 1 by welding or the like. Thereby, the bellows 5 hermetically seals the valve chamber 1A and the adjustment chamber 41A. Therefore, leakage of refrigerant from the valve body 10 can be completely eliminated. Note that the inside of the adjustment chamber 41A has an atmospheric pressure that corresponds to the surrounding environment of the thermostatic expansion valve 100 when the lid member 44 is removed, through the gap between the female threaded portion 41a and the male threaded portion 42a. The lid member 44 is removed when adjusting the superheat degree setting value. Further, the bellows 5 has flexibility mainly in the direction of the axis X. The urging force of the urging spring 24 can then be transmitted to the valve body 2.

In the second embodiment shown in FIG. 3, the same members and elements as those in the first embodiment are denoted by the same reference numerals, and detailed explanations thereof will be omitted. The second embodiment differs from the first embodiment mainly in the orientation of the bellows 5'. The valve body 2' in this second embodiment is composed of a needle part 21', a flange part 22' on the outer periphery of the needle part 21', and a boss part 23' protruding on the opposite side from the needle part 21'. ing. Further, a retainer 25 is fitted into the boss portion 23' of the valve body 2', and a leaf spring 26 (chrysanthemum spring) that slides into contact with the inner wall of the valve chamber 1A is assembled to the retainer 25. Further, the bellows 5' serving as the "airtight member" in this embodiment is arranged with the end plate 51' (on the other side) as the lower end, and a stopper 53' is placed inside the bellows 5' in contact with the end plate 51'. It has been accommodated. Furthermore, a biasing spring 24 is disposed inside the bellows 5', and this biasing spring 24 is compressed between the stopper 53' and a leaf spring 26 on the valve body 2 side. The valve body 2 is urged in the valve closing direction by the urging spring 24.

The adjustment section 20' provided at the lower part of the valve housing 1 is constructed using an adjustment section housing 61 having an adjustment chamber 61A on the valve housing 1 side as a frame. The adjustment portion housing 61 is fixed to the valve housing 1 by screwing the open end of the adjustment chamber 61A to the lower end of the valve housing 1. Further, the adjustment chamber 61A of the adjustment unit housing 61 has a cylindrical shape, and a female threaded portion 61a is formed at the lower part of the adjustment chamber 61A. are combined. A ball 63 is disposed between the end of the adjustment spindle 62 on the adjustment chamber 61A side and the end plate 51' at the lower end (on the other side) of the bellows 5. Note that the lower part of the adjustment unit housing 61 and the lower part of the adjustment spindle 62 are covered by a lid member 64. Further, as in the first embodiment, the adjustment section housing 61 is provided with a seal member S', and the space between the adjustment section housing 61 and the lid member 64 is sealed. Similarly to the first embodiment, the volume of the adjustment chamber 61A is set to be sufficiently large as in the first embodiment. In this embodiment, the volume of the adjustment chamber 61A can be made larger by providing the adjustment spindle 62 with a communication hole that communicates the space in the adjustment housing 61 that accommodates the lid member 64 and the space that accommodates the bellows 5. .

In this embodiment, the bellows 5' has a flat part 5b' at the end opposite to the end plate 51' (one side) fixed to the end of a ring-shaped fixture 52' by welding or the like. The bellows 5' is fixed to the valve housing 1 by fitting the fixing fitting 52' into the annular rim portion 1a at the lower end of the valve housing 1 and fixing it by brazing or the like. Thereby, the bellows 5' hermetically seals the valve chamber 1A and the adjustment chamber 61A. Therefore, leakage of refrigerant from the valve body 10 can be completely eliminated. Note that the inside of the adjustment chamber 61A has an atmospheric pressure that corresponds to the surrounding environment of the thermostatic expansion valve 100 when the lid member 64 is removed, through a gap between the female threaded portion 61a and the male threaded portion 62a. The lid member 64 is removed when adjusting the superheat degree setting value. Further, the bellows 5' has flexibility mainly in the direction of the axis X. The urging force of the urging spring 24 can then be transmitted to the valve body 2. In this way, in the second embodiment, since the other side of the bellows 5' is provided on the adjustment spindle 62 side of the adjustment section 20', the valve body 2' can move toward or away from the valve port 13. Even if this is done, the bellows 5' will not expand or contract accordingly. This makes it difficult for changes in the elastic force of the bellows 5' to affect the flow characteristics. Also, similar to the first embodiment, the bellows 5' is installed in the valve chamber 1A in a contracted state.

FIG. 4 is a schematic configuration diagram of the refrigeration cycle system according to the embodiment. This refrigeration cycle system is used in air conditioners such as room air conditioners, refrigeration equipment such as showcases, refrigeration equipment, and the like. In FIG. 4, 100 is a thermostatic expansion valve of each embodiment, 200 is an indoor heat exchanger which is an evaporator, 300 is an outdoor heat exchanger which is a condenser, and 400 is a compressor. The refrigerant compressed by the compressor 400 flows into the outdoor heat exchanger 300, is throttled by the thermostatic expansion valve 100, and is circulated to the compressor 400 via the indoor heat exchanger 200. The outdoor heat exchanger 300 functions as a condenser, the indoor heat exchanger 200 functions as an evaporator, and the room is cooled.

A temperature sensing cylinder 30 is attached to an outlet side piping 200a of the indoor heat exchanger 200 (evaporator) via a capillary tube 30a extending from the thermostatic expansion valve 100. Then, the temperature sensing cylinder 30 senses the temperature of the outlet pipe 200a, applies pressure corresponding to the temperature to the diaphragm device 3, and changes the valve opening degree of the thermostatic expansion valve 100 as described above.

Note that there are two types of thermostatic expansion valves: internal pressure equalization type and external pressure equalization type, which are used depending on the magnitude of pressure loss inside the evaporator. An internal pressure equalization method is used when the pressure loss is constant or small, and an external pressure equalization method is used when the pressure loss is large. In the embodiment, an example of an internal pressure equalization type in which the pressure of the valve chamber 1A is introduced into the pressure equalization chamber 32A has been described, but the present invention is an external pressure equalization type in which the outlet pressure of the evaporator is introduced into the pressure equalization chamber 32A through a pressure equalization conduit. It can also be applied to pressure type.

The embodiments of the present invention have been described above in detail with reference to the drawings, and other embodiments have also been described in detail, but the specific configuration is not limited to these embodiments. Even if there are changes in the design within the scope of the invention, they are included in the present invention.

10 Valve body part 20, 20' Adjustment part 30 Temperature sensing cylinder 30a Capillary tube Biasing spring 3 Diaphragm device 31 Upper cover 31A Pressure receiving chamber 32 Lower cover 32A Pressure equalization chamber 33 Diaphragm 34 Wet 35 Operating rod 41 Adjustment housing 41A Adjustment chamber 42 Adjustment spindle 5, 5' Bellows 51, 51' End plate 5a Rim part 5b' Flat part 61 Adjustment unit housing 61A Adjustment chamber 62 Adjustment spindle 100 Thermostatic expansion valve 200 Indoor heat exchanger (evaporator)
300 Outdoor heat exchanger (condenser)
400 compressor

Claims (3)

The superheat degree setting value is adjusted by adjusting the biasing force of a biasing spring that is connected by piping between the condenser and evaporator of the refrigeration cycle system and biases the valve body in the valve closing direction on the axis of the valve port. In the thermostatic expansion valve,
comprising: a valve body with the valve body built into the valve chamber; and an adjustment part with an adjustment spindle facing inside the valve body for expanding and contracting the biasing spring in the axial direction;
The inside of the valve body portion and the adjustment chamber of the adjustment portion are partitioned by a flexible airtight member,
One side of the airtight member is joined to the valve body, and the other side is disposed on the axis of the adjustment spindle between the inside of the valve body and the adjustment spindle ,
The temperature type expansion valve , wherein the other side of the airtight member is provided on the adjustment spindle side of the adjustment section . The thermostatic expansion valve according to claim 1 , wherein the airtight member is a bellows. A refrigeration cycle system including a compressor, a condenser, an evaporator, and a throttle device, characterized in that the thermostatic expansion valve according to claim 1 or 2 is used as the throttle device. refrigeration cycle system.

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