CN113944772A

CN113944772A - Check valve and refrigeration cycle system

Info

Publication number: CN113944772A
Application number: CN202110747113.8A
Authority: CN
Inventors: 滨田正吾
Original assignee: Saginomiya Seisakusho Inc
Current assignee: Saginomiya Seisakusho Inc
Priority date: 2020-07-15
Filing date: 2021-07-02
Publication date: 2022-01-18
Also published as: JP2022018217A; JP7362555B2

Abstract

The invention provides a check valve and a refrigeration cycle system capable of reducing pressure loss of fluid in positive flow and increasing flow rate. The check valve (1) is provided with a cylindrical outer pipe section (2), a valve body (3) built in the outer pipe section (2), and a valve element (4) provided in the valve body (3). The valve body (3) has a cylindrical valve frame (5) that supports the valve body (4), a valve seat portion (6) on which the valve body (4) can be seated, and a valve port (7) that is closed by the seated valve body (4), and the valve body (4) is provided so as to be axially movable within the valve frame (5) between a valve-closed position at which the valve body is seated on the valve seat portion (6) and a valve-open position at which the valve body is separated from the valve seat portion (6). A valve frame (5) is provided with a communication hole (21) which penetrates through the cylindrical peripheral surface and communicates the interior of the outer pipe part (2) with the valve port (7), and a part of the communication hole (21) is blocked by the valve element (4) which moves to the valve opening position.

Description

Check valve and refrigeration cycle system

Technical Field

The present invention relates to a check valve and a refrigeration cycle system.

Background

Conventionally, as a check valve, there is known a check valve including a valve body provided in an outer pipe and a valve body provided in the valve body, the valve body having a valve seat portion constituting a valve port and a cylindrical valve frame for movably housing the valve body (see, for example, patent document 1). In this check valve, a communication hole (communication hole) that communicates the inside of the outer pipe with the valve port is provided in a valve housing (valve case), and the valve body moves toward the outlet side in the valve housing with respect to a normal flow that is a normal flow of fluid, and the fluid that flows in from the valve port (inflow port) passes through the inside of the outer pipe from the communication hole and flows out from the outflow port.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Sho 47-34622

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional check valve described in patent document 1, although the valve body moves to the valve open position and the communication hole is fully opened at the time of the positive flow, there is a problem that the pressure loss of the fluid at the time of passing through the communication hole becomes large and the flow rate of the fluid is suppressed.

An object of the present invention is to provide a check valve and a refrigeration cycle system capable of reducing pressure loss of a fluid at the time of positive flow and increasing a flow rate.

Means for solving the problems

The check valve of the present invention includes a cylindrical outer tube portion extending in an axial direction, a valve main body built in the outer tube portion, and a valve body provided in the valve main body, and is characterized in that the valve main body includes a cylindrical valve frame supporting the valve body, a valve seat portion on which the valve body can be seated, and a valve port closed by the valve body seated on the valve seat portion, the valve body is provided movably in the axial direction between a valve closing position seated on the valve seat portion and a valve opening position separated from the valve seat portion in the valve frame, the valve frame is provided with a communication hole penetrating a cylindrical peripheral surface and communicating an inside of the outer tube portion with the valve port, and a part of the communication hole is closed by the valve body moved to the valve opening position.

According to the present invention, the valve body moved to the valve open position closes a part of the communication hole of the valve frame, so that the pressure loss of the fluid when passing through the communication hole can be reduced, and the flow rate in the positive flow can be increased.

In this case, it is preferable that the communication hole is formed in a circular shape in side view, and the valve body is formed in a cylindrical shape or a bottomed cylindrical shape. According to this configuration, when the communication hole is formed in a circular shape in side view, if the valve body completely opens the communication hole, a vortex of fluid is generated at a boundary portion between the distal end surface of the valve body and the inner surface of the valve body, and the pressure loss increases.

Further, it is preferable that an opening degree of a portion of the communication hole not closed by the valve body moved to the open valve position is 55 to 75%.

Preferably, an entire surface of a distal end surface of the valve body facing the valve seat portion is formed flat, or an outer peripheral portion of the distal end surface of the valve body facing the valve seat portion, which is in contact with the valve seat portion, is formed flat. According to such a configuration, at least the outer peripheral portion of the distal end surface of the valve body is formed flat, and the distal end portion of the outer peripheral surface of the valve body that is in sliding contact with the inner peripheral surface of the valve frame has an end edge perpendicular to the axial direction, so that the area of the communication hole that is closed when the valve body is moved to the valve-opening position can be made constant, and the flow rate can be stabilized.

Preferably, the outer tube portion includes a first tube portion on a primary side, a second tube portion that fixes the valve seat portion, and a third tube portion that covers an outer side of the valve frame on a secondary side, and a relationship between a diameter dimension D2 of the second tube portion and a diameter dimension D3 of the third tube portion is D2 < D3.

Preferably, the outer tube portion includes a first tube portion on a primary side, a second tube portion fixing the valve seat portion, and a third tube portion covering an outer side of the valve frame on a secondary side, a relationship among a diameter dimension D1 of the first tube portion, a diameter dimension D2 of the second tube portion, and a diameter dimension D3 of the third tube portion is D1 < D2 < D3, and an inner diameter of the valve seat portion is substantially the same as an inner diameter of the first tube portion.

The refrigeration cycle system of the present invention is characterized by comprising any one of the check valves described above.

The effects of the invention are as follows.

According to the check valve and the refrigeration cycle system of the present invention, the flow rate at the time of positive flow can be increased by suppressing the pressure loss of the fluid when the communication hole of the valve frame passes.

Drawings

Fig. 1 is a sectional view showing a check valve according to a first embodiment of the present invention.

Fig. 2 is an enlarged sectional view showing a main portion of the check valve in an enlarged manner.

Fig. 3 is a view illustrating the opening degree of the communication hole of the check valve.

Fig. 4 is a diagram illustrating the flow of fluid in the check valve and the comparative example.

Fig. 5 is a graph showing the relationship between the valve opening degree of the communication hole and the flow rate.

Fig. 6 is an enlarged cross-sectional view showing a modification of the check valve.

Fig. 7 is an enlarged cross-sectional view showing a modification of the check valve.

Fig. 8 is a sectional view showing a check valve according to a second embodiment of the present invention.

Fig. 9 is an enlarged sectional view and a side view showing a main part of the check valve in an enlarged manner.

Fig. 10 is a diagram showing a refrigeration cycle system of the present invention.

Description of the symbols

1. 1A-check valve, 2-outer tube part, 3-valve body, 4-valve core, 5A-valve holder, 6A-valve seat part, 7-valve port, 11B-primary cylindrical part (first tube part), 13-first diameter-expanding part (second tube part), 14-second diameter-expanding part (third tube part), 21-communication hole, 32-front end face, 50-refrigeration cycle.

Detailed Description

A check valve according to a first embodiment of the present invention will be described with reference to fig. 1 to 5. As shown in fig. 1, the check valve 1 of the present embodiment is a valve device that allows a fluid to flow (positive flow) from a primary side (left side in fig. 1) to a secondary side (right side in fig. 1) and prohibits a fluid from flowing (reverse flow) from the secondary side to the primary side. The check valve 1 includes a cylindrical outer tube portion 2 extending in an axial direction along the axis L, a valve body 3 built in the outer tube portion 2, and a valve element 4 provided in the valve body 3. The valve main body 3 is a brass member in which a cylindrical valve frame 5 supporting the valve body 4 and a seat portion 6 on which the valve body 4 can be seated are integrally formed, and a valve port 7 closed by the seated valve body 4 is formed in the seat portion 6.

The outer tube section 2 is an integrally formed member made of copper, and includes a primary joint section 11 on the primary side, a secondary joint section 12 on the secondary side, a first diameter-enlarged section 13 that is larger in diameter than the primary joint section 11, and a second diameter-enlarged section 14 that is larger in diameter than the first diameter-enlarged section 13 and is continuous with the secondary joint section 12. The primary joint 11 has a primary opening 11A connected to a primary pipe (not shown), a cylindrical primary cylindrical portion 11B continuous with the primary opening 11A, and a first connecting portion 11C having a diameter expanding from the primary cylindrical portion 11B toward the first diameter expanding portion 13, and the primary opening 11A is slightly larger in diameter than the primary cylindrical portion 11B. The secondary joint 12 has a secondary opening 12A connected to a secondary pipe (not shown), a cylindrical secondary cylindrical portion 12B continuous with the secondary opening 12A, and a second connecting portion 12C expanding in diameter from the secondary cylindrical portion 12B toward the second diameter-expanded portion 14, and the secondary opening 12A is slightly larger in diameter than the secondary cylindrical portion 12B.

The first enlarged diameter portion 13 is a portion that holds the seat portion 6 that is pressed into the interior thereof, and a fixing portion 13A that deforms radially inward to fix the seat portion 6 is formed at four portions of the circumferential surface. The fixing portion 13A is swaged by a punch of a press machine and fitted into the annular recess 25 of the valve seat portion 6, thereby fixing the valve seat portion 6 at a predetermined position inside the outer tube portion 2. The inner peripheral surface of the second diameter-enlarged portion 14 faces the outer peripheral surface of the valve frame 5 with a predetermined gap therebetween, and the second diameter-enlarged portion 14 is formed in a cylindrical shape having an inner diameter dimension to such an extent that fluid smoothly flows through the gap. A step portion 14A that reduces the diameter toward the first enlarged diameter portion 13 is provided at a boundary portion between the second enlarged diameter portion 14 and the first enlarged diameter portion 13. In the above outer tube portion 2, the inner diameter D1 (see fig. 1) of the primary cylindrical portion 11B (first tube portion) of the primary joint portion 11, the inner diameter D2 (see fig. 2) of the first enlarged diameter portion 13 (second tube portion), and the diameter D3 (see fig. 2) of the second enlarged diameter portion 14 (third tube portion) are in the relationship of D1 < D2 < D3.

Communication holes 21 penetrating the cylindrical peripheral surface in the radial direction are provided at four locations of the valve body 3 in the valve holder 5, and the inside of the valve holder 5 and the inside of the second enlarged diameter portion 14 of the outer tube portion 2 are communicated by the communication holes 21. The communication hole 21 is formed in a circular shape in side view. That is, the communication hole 21 is formed by drilling the valve frame 5 with a drill or the like from a direction perpendicular to the axis. An annular valve stopper 22 made of SUS is attached to an inner surface of the valve frame 5 near the secondary end, and the valve body 4 moved to the valve opening position (the position shown in fig. 1 and 2) abuts against the valve stopper 22 to restrict the movement of the valve body 4 to the secondary side from the valve opening position. That is, the valve-open position is a position at which the valve body 4 is separated from the valve seat portion 6, and is a position at which the valve body 4 abuts against the valve stopper 22 to restrict the valve body 4 from moving further to the secondary side than the valve stopper 22 (secondary-side direction maximum position in the valve stroke).

The seat portion 6 has a cylindrical portion 23 extending to the primary side, a tapered seat surface 24 is provided on an inner surface of a secondary side (valve frame 5 side) end portion of the cylindrical portion 23, and the valve body 4 moved to the valve closing position is seated on the seat surface 24. The inner diameter of the valve seat portion 6, i.e., the inner diameter dimension D4 (see fig. 2) of the valve port 7 is substantially the same as the inner diameter dimension D1 (see fig. 1) of the primary cylindrical portion 11B (first pipe portion) of the primary joint portion 11. An annular recess 25 into which the fixing portion 13A of the outer pipe portion 2 is fitted is formed on the outer surface of the cylindrical portion 23 in the vicinity of the primary side end portion. An annular projection 26 projecting in the radial direction is formed on the outer surface of the secondary side end of the valve seat portion 6,the annular projection 26 abuts against the inner surface of the step portion 14A of the outer pipe portion 2, thereby positioning the valve body 3 with respect to the outer pipe portion 2 and CO₂When used under an ultrahigh pressure such as a refrigerant, the force received by the seat portion 6 in the valve closing direction when the valve is closed can be received by the inner surface of the stepped portion 14A, and thus the press-fitting deviation of the seat portion 6 can be prevented. The annular projection 26 is formed with a D-shaped cut portion 27 in which a part of the circumferential direction is cut off.

The valve body 4 is a cylindrical resin member having an outer diameter slightly smaller than an inner diameter of the valve frame 5, and is provided in the valve frame 5 so as to be axially movable along an inner peripheral surface of the valve frame 5. The valve body 4 has an outer peripheral surface 31 which is a cylindrical peripheral surface, a front end surface 32 which is a primary end surface, and a rear end surface 33 which is a secondary end surface. The entire surfaces of the front end surface 32 and the rear end surface 33 of the valve body 4 are formed flat. The valve body 4 is not limited to a cylindrical shape, and may be formed in a bottomed cylindrical shape having a bottom on the front end surface 32 side and an opening on the rear end surface 33 side. The cylindrical outer peripheral surface 31 of the valve element 4 may have a shape in which the outer diameter is reduced in a certain range in the middle of the axial direction L, and may have a portion in which the outer diameter is reduced from the outer diameters of the front end surface 32 and the rear end surface 33 in the middle, and the entire periphery of the reduced portion may be formed of a rectangular or arc-shaped recess.

In the valve-closed position, the outer peripheral edge of the front end surface 32 of the valve body 4 abuts against and is seated on the seat surface 24 of the seat portion 6, whereby the valve port 7 is closed to prevent the reverse flow of the fluid from the secondary side to the primary side. On the other hand, in the valve open position shown in fig. 1 and 2, the outer peripheral portion of the rear end surface 33 of the valve body 4 abuts against the valve stopper 22 and is restricted from moving. In the valve open position, the distal end surface 32 of the valve element 4 is positioned on the primary side with respect to the secondary side edge of the communication hole 21. That is, the outer peripheral surface 31 of the valve body 4 moved to the valve-open position closes a part of the communication hole 21.

The positional relationship between the valve element 4 and the communication hole 21 in the valve open position, the valve opening degree of the communication hole 21, and the flow rate of the fluid will be described with reference to fig. 3 to 5. Fig. 3 shows a state in which a part of the communication hole 21 is blocked by the valve body 4. As shown by symbol a in fig. 3, when the distal end surface 32 of the valve body 4 is positioned at the center in the axial direction of the communication hole 21, half of the hole diameter of the communication hole 21 is closed and half is opened, and thus the valve opening degree of the communication hole 21 is 50%. When the distal end surface 32 of the valve body 4 is located at the position indicated by symbol B in fig. 3, 1/4, which is the hole diameter of the communication hole 21, is closed and 3/4 is opened, so that the valve opening of the communication hole 21 is 75%. If the valve body 4 does not overlap the communication hole 21, the valve opening degree of the communication hole 21 becomes 100%. Here, the valve opening degree of the communication hole 21 is defined as follows. The valve opening degree of the communication hole 21 is a ratio of a maximum length of an unblocked portion of the communication hole 21 in the axis L direction to a hole diameter (maximum length) of the communication hole 21 in the axis L direction at the valve-open position.

Fig. 4 (a) shows the flow of the fluid when the check valve 1 of the present embodiment is opened, and fig. 4 (B) shows the flow of the fluid when the check valve 100 is opened, in which the valve opening of the communication hole 21 is 100% when the check valve is opened, as a comparative example. As shown in fig. 4 (B), in the check valve 100 of the comparative example, the tip end surface 32 of the valve body 4 is located at the same position as the end edge of the communication hole 21, and therefore, in the portion adjacent to the circular communication hole 21, a vortex of the fluid is generated at the boundary portion between the inner peripheral surface of the valve frame 5 and the tip end surface 32 of the valve body 4 as shown in the drawing, and the flow of the fluid is blocked by the vortex, so that the pressure loss of the fluid increases, and the flow rate decreases. In contrast, as shown in fig. 4 (a), in the check valve 1 of the present embodiment, the fluid that has flowed into the valve frame 5 flows smoothly toward the communication hole 21 at a portion where the vortex of the fluid is not generated, and the pressure loss of the fluid is reduced. Even when the end face 32 of the valve element 4 is located on the secondary side of the end edge of the communication hole 21, a vortex flow of the fluid is generated in the boundary portion between the inner peripheral surface of the valve frame 5 and the end face 32 of the valve element 4, and the flow of the fluid is inhibited by the vortex flow, as in the case where the end face 32 of the valve element 4 is located at the same position as the end edge of the communication hole 21.

Fig. 5 is a graph showing a relationship between the valve opening degree of the communication hole 21 and the flow rate. The graph shows the flow rate for each valve opening degree calculated by simulation by changing the valve opening degree of the communication hole 21 between 50% and 100%, and the flow rate when the valve opening degree is 100% is shown as 1.0. As shown in fig. 5, the flow rate of the fluid has a maximum value when the valve opening degree is 65%, and is 1.1 times the flow rate when the valve opening degree is 100%. Further, the valve opening degree is 55% to 75%, and the flow rate is 1.08 times or more with respect to the flow rate when the valve opening degree is 100%.

Next, a modification of the valve body 4 in the check valve 1 will be described with reference to fig. 6 and 7. The valve body 4 of the first modification shown in fig. 6 (a) has a valve sheet (i.e., an end シート)34A that can come into contact with the valve seat surface 24, an engagement ring 34B that engages the valve sheet 34A, and a rivet piece 34C that rivet-fixes the engagement ring 34B, and constitutes the front end surface 32. In this valve body 4, the primary side of the valve sheet 34A is formed flat, that is, the outer peripheral portion of the valve body 4 abutting against the valve seat portion 6 is formed flat.

The front end surface 32 of the valve body 4 of the second modification shown in fig. 6 (B) is formed to have a flat surface portion 35A formed flat on the outer peripheral side and a columnar protruding portion 35B protruding toward the primary side at the center portion. In this valve body 4, a flat surface portion 35A constituting the outer peripheral portion of the distal end surface 32 abuts on the valve seat portion 6. In the valve body 4 at the valve opening position, the fluid flowing from the valve port 7 is guided to the communication hole 21 along the flat surface portion 35A after hitting the protrusion portion 35B. The tip end surface 32 of the valve body 4 of the third modification shown in fig. 6 (C) is formed in a spherical shape protruding toward the primary side, the tip end surface 32 of the valve body 4 of the fourth modification shown in fig. 6 (D) is formed in a truncated conical shape protruding toward the primary side, the tip end surface 32 of the valve body 4 of the fifth modification shown in fig. 7 (a) is formed in a conical shape protruding toward the primary side, and the fluid is also guided to the communication hole 21 along the tip end surface 32 in the valve body 4.

The front end surface 32 of the valve body 4 of the sixth modification shown in fig. 7 (B) is formed to have a flat surface portion 36A formed flat on the outer peripheral side and a conical projecting portion 36B projecting toward the primary side at the central portion. In this valve body 4, a flat surface portion 36A constituting the outer peripheral portion of the distal end surface 32 abuts on the valve seat portion 6. In the valve body 4 in the valve opening position, the fluid flowing from the valve port 7 is guided to the communication hole 21 along the flat surface portion 36A after hitting the protrusion portion 36B. The front end surface 32 of the valve body 4 of the seventh modification shown in fig. 7 (C) is formed to have a flat surface portion 37A formed flat on the outer peripheral side and a recessed portion 37B recessed toward the secondary side at the central portion, and the front end surface 32 of the valve body 4 of the eighth modification shown in fig. 7 (D) is formed to have a flat surface portion 38A formed flat on the outer peripheral side and a recessed portion 38B recessed toward the secondary side in a conical shape at the central portion, and in the valve body 4, the

flat surface portions

37A, 38A constituting the outer peripheral portion of the front end surface 32 are in contact with the valve seat portion 6.

According to the present embodiment described above, the valve body 4 moved to the valve open position blocks a part of the communication hole 21 of the valve frame 5, so that the pressure loss of the fluid when passing through the communication hole 21 can be reduced, and the flow rate in the positive flow can be increased.

Further, since the circular arc-shaped portion on the secondary side of the circular communication hole 21 is closed by the valve element 4 in a side view, an eddy current is less likely to be generated in a boundary portion between the distal end surface 32 of the valve element 4 and the inner circumferential surface of the valve holder 5, and pressure loss of the fluid when the communication hole 21 passes can be effectively suppressed.

Further, the opening degree of the communication hole 21 partially blocked by the valve element 4 at the valve open position is set to 55 to 75%, and a flow rate 1.08 times or more can be secured as compared with the case where the opening degree is 100%. Therefore, if the valve opening degree is set to be 55% to 75% in the open position, even if the valve opening degree varies slightly depending on the size, shape, and the like of the member, the maximum flow rate can be obtained in the normal flow.

Further, since at least the outer peripheral portion of the distal end surface 32 of the valve body 4 is formed flat, the distal end portion of the outer peripheral surface 31 of the valve body 4 which is in sliding contact with the inner peripheral surface of the valve holder 5 has an end edge perpendicular to the axial direction, and the area for closing the communication hole 21 at the valve opening position can be made constant, and the flow rate can be stabilized.

Further, as shown in fig. 6 (a) to (D) and fig. 7 (a) and (B), in the valve body 4, the center portion of the distal end surface 32 protrudes toward the primary side, and the outer peripheral portion is formed flat, so that the fluid flowing in from the valve port 7 is guided to the communication hole 21 along the outer peripheral portion after hitting the center portion of the distal end surface 32, and the fluid can smoothly flow to the communication hole 21.

In the outer tube 2, the inner diameter D2 of the first enlarged diameter portion 13 (second tube) and the diameter D3 of the second enlarged diameter portion 14 (third tube) are in the relationship of D2 < D3, so that a space flow area can be ensured between the outer diameter of the valve frame 5 and the inner diameter of the outer tube 2, and therefore, the pressure loss flowing out from the communication hole 21 to the secondary side can be reduced. Further, in the outer tube portion 2, the inner diameter D1 of the first tube portion, the inner diameter D2 of the first enlarged diameter portion 13 (second tube portion), and the diameter D3 of the second enlarged diameter portion 14 (third tube portion) are in the relationship of D1 < D2 < D3, and the inner diameter D4 of the valve port 7, which is the inner diameter of the valve seat portion 6, is substantially the same as the inner diameter D1 of the first tube portion, so that the flow from the first tube portion to the valve seat portion 6A becomes smooth, and a space flow passage area can be secured between the outer diameter of the valve frame 5 and the inner diameter of the outer tube portion 2, and therefore, the pressure loss flowing out from the communication hole 21 to the secondary side can be reduced, and the flow rate can be further increased.

Next, a check valve 1A according to a second embodiment of the present invention will be described with reference to fig. 8 and 9. The check valve 1A of the present embodiment is configured to include an outer pipe portion 2, a valve body 3, and a valve body 4, as in the check valve 1 of the first embodiment. On the other hand, the check valve 1A is different in a part of the structure of the valve body 3 from the check valve 1. Hereinafter, the different points will be described in detail.

The valve body 3 of the check valve 1A of the present embodiment is formed by separating the valve frame 5A and the seat portion 6A and is welded and fixed to each other. The valve frame 5A is a cylindrical member made of SUS, and communication holes 21 penetrating the circumferential surface thereof in the radial direction are provided at four locations. A valve stopper 28 bent radially inward is provided at the secondary side end of the valve holder 5A, and the valve element 4 moved to the valve open position (the position shown in fig. 8 and 9) abuts against the valve stopper 28 to restrict the movement of the valve element 4 to the secondary side of the valve open position.

The valve seat portion 6A is a cylindrical member made of SUS, and has a cylindrical portion 23 similar to the valve seat portion 6, and an annular projecting valve seat 29 is provided at a secondary side (valve frame 5 side) end portion of the cylindrical portion 23, and the valve body 4 moved to the valve closing position is seated on the valve seat 29. In the valve-closed position, the outer peripheral portion of the distal end surface 32 of the valve element 4 abuts against and is seated on the valve seat 29, whereby the valve port 7 is closed to prevent the reverse flow of the fluid from the secondary side to the primary side. On the other hand, in the valve-open position shown in fig. 8 and 9, the distal end surface 32 of the valve element 4 is positioned on the primary side with respect to the secondary-side end edge of the communication hole 21, and the outer peripheral surface 31 of the valve element 4 closes a part of the communication hole 21.

Fig. 9 (B) is a side view of the valve body 3 of fig. 9 (a) as viewed from the secondary side (right side in the drawing). As shown in fig. 9 (B), a D-shaped cut portion 27, a part of which is cut out in the circumferential direction, is formed in the annular protrusion 26 of the valve seat portion 6A. Here, the annular convex portion 26 of the valve seat portion 6A abuts against the inner surface of the stepped portion 14A of the outer tube portion 2, but a liquid seal portion 26A as a minute gap is formed therebetween. When the refrigerant as a fluid enters and accumulates in the liquid seal portion 26A and is rapidly exposed to a high temperature in a state where the refrigerant is cooled and liquefied, the liquid refrigerant rapidly expands in volume, but the D-cut portion 27 communicates with the liquid seal portion 26A, and the expanded refrigerant flows out into the outer tube portion 2. Therefore, the outer tube portion 2 and the valve seat portion 6A can be prevented from being damaged or deformed by the expansion pressure of the refrigerant.

According to the present embodiment described above, as in the first embodiment, the valve body 4 moved to the valve-open position closes a part of the communication hole 21 of the valve frame 5A, so that the pressure loss of the fluid when passing through the communication hole 21 can be reduced, and the flow rate in the positive flow can be increased.

Next, a refrigeration cycle system of the present invention will be described with reference to fig. 10. Fig. 10 is a diagram showing a refrigeration cycle system 50 of the embodiment. The refrigeration cycle 50 is used for an air conditioner such as a commercial air conditioner. In the refrigeration cycle 50, an indoor heat exchanger 51, an outdoor heat exchanger 52, an expansion valve 53, a four-way valve 54, and three compressors 55 connected in parallel are connected by pipes. In order to prevent the refrigerant from flowing backward to the compressors 55, the

check valves

1 and 1A are connected between the discharge (high-pressure output) side of the compressors 55 and the four-way valve 54 with the compressor 55 as the primary side and the four-way valve 54 as the secondary side.

During the cooling operation, as indicated by a solid arrow D51, the refrigerant having absorbed heat in the indoor heat exchanger 51 flows through the four-way valve 54 to the compressor 55, is compressed by the compressor 55, and then reaches the outdoor heat exchanger 52 through the

check valves

1 and 1A and the four-way valve 54. Then, the heat is released from the outdoor heat exchanger 52, and then returned to the indoor heat exchanger 51 via the expansion valve 53. During the heating operation, as indicated by a broken line arrow D52, the refrigerant that has released heat in the indoor heat exchanger 51 reaches the outdoor heat exchanger 52 via the expansion valve 53. After absorbing heat in the outdoor heat exchanger 52, the refrigerant flows through the four-way valve 54 to the compressor 55, is compressed by the compressor 55, and then returns to the indoor heat exchanger 51 through the

check valves

1 and 1A and the four-way valve 54. The refrigeration cycle 50 repeats the above-described cycle to cool or heat the room.

Here, for example, under the condition of a large cooling load, the three compressors 55 are simultaneously operated, and therefore the three

check valves

1 and 1A are in the fully open state. In the case where the cooling load is small, only one compressor 55 is sufficiently operated, and therefore the other two compressors 55 are not operated. At this time, the secondary pressure of the two

check valves

1, 1A is higher than the primary pressure, and a reverse flow from the secondary side occurs, so that the two

check valves

1, 1A are in a closed state.

The embodiments and modifications described above are merely representative embodiments of the present invention, and the present invention is not limited thereto. That is, various modifications can be made without departing from the scope of the present invention. Such a modification is naturally included in the scope of the present invention as long as the structure of the check valve of the present invention is provided.

For example, in the above-described embodiments and modifications, the

check valves

1 and 1A used in air conditioners such as commercial air conditioners are exemplified, but the check valves are not limited to commercial air conditioners, may be used in household air conditioners, and may be applied to various refrigerators, and the like without being limited to air conditioners. The various refrigeration cycles described above are not limited to those attached to the discharge side of the compressor as in the check valve attachment example of the refrigeration cycle of fig. 10, and can be applied to various locations in various refrigeration cycles for backflow prevention. Further, as the refrigerant of each refrigeration cycle, there are various refrigerants (for example, various freon refrigerants, hydrocarbon refrigerants, CO)₂Natural production of ammonia and the likeRefrigerant, etc.), the check valve of the present invention can be applied to a refrigeration cycle corresponding to any of the above refrigerants.

In the above description of the first embodiment, the first to eighth modifications, and the second embodiment, the communication hole 21 has been described as being provided at four locations penetrating the cylindrical peripheral surface of the valve frame 5 in the radial direction, but the communication hole is not limited to four locations, and may be provided at one location or at a plurality of locations including two or more locations. The communication hole 21 is described as a circular hole in side view, but is not limited to a circular shape in side view, and may be an elliptical shape. In the first embodiment, the first to eighth modifications, and the second embodiment, the description has been given of the check valve in which the outer pipe portion 2 (the joint member and the body member) is formed integrally of copper, but the present invention can also be applied to a check valve in which the inlet and outlet copper pipe joint members and the body member that houses the valve element are formed separately.

While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to the embodiments, and the present invention includes design modifications and the like without departing from the scope of the present invention.

Claims

1. A check valve comprising a cylindrical outer tube portion extending in an axial direction, a valve body built in the outer tube portion, and a valve body provided in the valve body,

the valve main body includes a cylindrical valve frame supporting the valve body, a valve seat portion on which the valve body can be seated, and a valve port closed by the valve body seated on the valve seat portion,

the valve body is provided in the valve frame so as to be movable in the axial direction between a valve-closed position where the valve body is seated on the valve seat portion and a valve-open position where the valve body is separated from the valve seat portion,

the valve frame is provided with a communication hole which penetrates the cylindrical peripheral surface and communicates the interior of the outer tube part with the valve port,

the valve body moved to the open valve position closes a part of the communication hole.

2. The check valve of claim 1,

the communication hole is formed in a circular shape in side view, and the valve body is formed in a cylindrical shape or a bottomed cylindrical shape.

3. The check valve of claim 1 or 2,

the opening degree of the portion of the communication hole not blocked by the valve element moved to the open valve position is 55-75%.

4. The check valve according to any one of claims 1 to 3,

the entire surface of the tip end surface of the valve body facing the valve seat portion is formed flat, or the outer peripheral portion of the tip end surface of the valve body facing the valve seat portion, which is in contact with the valve seat portion, is formed flat.

5. The check valve according to any one of claims 1 to 4,

the outer pipe part includes a first pipe part on the primary side, a second pipe part fixing the valve seat part, and a third pipe part covering the outside of the valve frame on the secondary side,

the relationship between the diameter D2 of the second tube part and the diameter D3 of the third tube part is D2 < D3.

6. The check valve according to any one of claims 1 to 4,

the relation among the diameter D1 of the first tube part, the diameter D2 of the second tube part, and the diameter D3 of the third tube part is D1 < D2 < D3,

the inner diameter of the valve seat portion is substantially the same as the inner diameter of the first pipe portion.

7. A refrigeration cycle system is characterized in that,

a check valve according to any one of claims 1 to 6.