non-return valve

Abstract

To provide a check valve that ensures high sealing performance and does not lose a backflow prevention function even when a large fluid pressure acts thereon.SOLUTION: A check valve 1 includes a flow passage member 14 having an inner peripheral surface 12 that defines a fluid passage 10, a valve element 16 disposed in the fluid passage 10 to be displaceable between a close position for closing the fluid passage 10 and an open position for opening the fluid passage 10, and a reinforcement member 36 disposed at an upstream end 34 of the valve element 16. At least a portion of the flow passage member 14 where a locking surface 50 is formed, and the reinforcement member 36 are formed of a material having higher rigidity than the valve element 16. When the valve element 16 receives force to the upstream side and further displaces to the upstream side from the close position while deforming a contact portion 30 of the valve element 16 that engages with a valve seat surface 32, the reinforcement member 36 engages with the locking surface 50 to support the valve element 16 with respect to the flow passage member 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a check valve. [Background technology]

[0002] A check valve for preventing backflow of a fluid typically includes a flow path member having a fluid passage and a valve element disposed within the fluid passage so as to be movable between a closed position that closes the fluid passage and an open position that opens the fluid passage. The valve element is biased upstream by a spring, and in the closed position, the spring's biasing force presses the valve element against the valve seat surface of the flow path member, sealing the valve element. The valve element is also pressed against the valve seat surface by fluid pressure from downstream. Check valves intended for relatively low-pressure fluids typically employ a seal ring made of an elastic material such as rubber attached to the valve element and sandwiched between the valve seat surface, ensuring a tight seal even with a relatively small pressing force. However, check valves intended for high-pressure fluids often employ a so-called metal seal structure, in which the valve element, made of a highly rigid metal material, is directly abutted against the valve seat surface, due to the risk of the seal ring becoming dislodged or being damaged by the high-pressure fluid (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-94962 Summary of the Invention [Problem to be solved by the invention]

[0004] Metal seal structures, in which highly rigid metals directly contact each other, have high pressure resistance, but because they are less likely to undergo elastic deformation upon contact, the valve disc and valve seat surface must be formed with high precision to achieve sufficient sealing. Furthermore, when the valve disc collides with the valve seat surface, a relatively loud noise is likely to be generated, and noise can become a problem, particularly if chattering occurs. On the other hand, if the valve disc is made of a low-rigidity material (e.g., a resin material), the valve disc is more likely to elastically deform to conform to the valve seat surface upon contact, making it relatively easy to achieve high sealing performance and reducing the noise upon collision. However, if the valve disc is made of a low-rigidity material, when excessive fluid pressure acts from downstream in the closed state, the valve disc may be damaged, losing its backflow prevention function and increasing the risk of high-pressure fluid being forcefully ejected upstream.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a check valve that ensures high sealing performance while not losing its backflow prevention function even when a large fluid pressure acts on it. [Means for solving the problem]

[0006] That is, the present invention provides: a flow path member having an inner circumferential surface that defines an upstream opening, a downstream opening, and a fluid passage extending from the upstream opening to the downstream opening, the inner circumferential surface having a valve seat surface and a locking surface that is located radially inward of the valve seat surface; a valve element disposed in the fluid passage so as to be displaceable between a closing position where the valve element engages with the valve seat surface to close the fluid passage and an opening position where the valve element moves away from the valve seat surface downstream to open the fluid passage; a reinforcing member disposed at an upstream end of the valve body; Equipped with At least a portion of the flow path member where the locking surface is formed and the reinforcing member are made of a material having a higher rigidity than the valve body, A check valve is provided in which, when the valve body is displaced further upstream from the closed position while the portion of the valve body that engages with the valve seat surface is deformed by a force acting upstream, the reinforcing member engages with the locking surface to support the valve body against the flow path member.

[0007] In this check valve, even if a large force, such as excessive fluid pressure acting from downstream on the valve disc in the closed position, causes the portion of the valve disc abutting the valve seat surface to deform, the reinforcing member engages with the locking surface of the flow path member to support the valve disc against the flow path member, preventing the valve disc from further deforming and displacing upstream. This prevents the valve disc from being damaged and losing its backflow prevention function, and makes it possible to prevent fluid from flowing back upstream. Meanwhile, because the valve disc can be made of a material with relatively low rigidity, a high level of sealing can be easily achieved between the valve disc and the valve seat surface, and the sound produced when the valve disc hits the valve seat surface can be reduced compared to when the valve disc is made of a highly rigid metal.

[0008] Furthermore, when the reinforcing member engages with the locking surface, the reinforcing member can close the fluid passage at the locking surface.

[0009] By the reinforcing member blocking the fluid passage, it is possible to more reliably prevent the valve body from deforming beyond the reinforcing member toward the upstream side.

[0010] The valve body may have a mounting hole extending downstream from the radial center position of the upstream end face of the valve body, and the reinforcing member may be inserted into the mounting hole and fixed to the valve body.

[0011] Furthermore, the valve body may be made of a resin material, and the flow path member and the reinforcing member may be made of a metal material.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a check valve according to the present invention will be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of a check valve according to an embodiment of the present invention in a closed state. [Figure 2] FIG. [Figure 3] 2 is a cross-sectional view of the check valve of FIG. 1 in an open state. [Figure 4] 2 is a cross-sectional view of the check valve of FIG. 1 in a state where the valve body is deformed and the reinforcing member is engaged with the locking surface of the flow path member. DETAILED DESCRIPTION OF THE INVENTION

[0014] As shown in FIG. 1 , the check valve 1 according to the present invention comprises a flow path member 14 having an inner circumferential surface 12 that defines a fluid passage 10, and a valve element 16 disposed within the fluid passage 10 so as to be displaceable along a longitudinal axis L. The fluid passage 10 extends along the longitudinal axis L from an upstream opening 18 to a downstream opening 20. The fluid passage 10 further includes a support member 22 attached to the inner circumferential surface 12 of the flow path member 14, and a spring 24 disposed between the valve element 16 and the support member 22. The support member 22 is held in place by a stop ring 28 fixed to an annular recess 26 in the inner circumferential surface 12. The valve element 16 is biased upstream by the spring 24, and a contact portion 30 of the valve element 16 is pressed against a valve seat surface 32 formed on the inner circumferential surface 12 of the flow path member 14. The contact portion 30 of the valve element 16 is sealingly engaged with the valve seat surface 32, thereby closing the fluid passage 10. In this embodiment, the flow path member 14 is made of a metal material (e.g., stainless steel), and the valve element 16 is made of a resin material (e.g., high-strength resin). Because the valve element 16 is made of a resin material that has lower rigidity than a metal material, when the valve element 16 is pressed against the valve seat surface 32, the valve element 16 elastically deforms in accordance with the valve seat surface 32, thereby improving the sealing performance between the valve element 16 and the valve seat surface 32.

[0015] The check valve 1 further includes a reinforcing member 36 disposed at the upstream end 34 of the valve disc 16. The reinforcing member 36 has a cylindrical main body 38 and a male threaded portion 40 extending from the main body 38. The valve disc 16 is formed with a mounting hole 44 extending downstream from the radial center of its upstream end face 42, and a female threaded portion 46 is formed in part of this mounting hole 44. The reinforcing member 36 is fixed to the valve disc 16 by inserting it into the mounting hole 44 and threading the male threaded portion 40 into the female threaded portion 46. As shown in FIG. 2 , the main body 38 of the reinforcing member 36 is formed with a tool engaging portion 48 that protrudes upstream. The reinforcing member 36 can be threaded onto the valve disc 16 by engaging a tool, such as a wrench, with the tool engaging portion 48 and rotating the reinforcing member 36.

[0016] When the fluid pressure at the upstream opening 18 is smaller than the combined force of the biasing force of the spring 24 and the fluid pressure at the downstream opening 20, the valve element 16 is pressed against the valve seat surface 32 of the flow path member 14 by the biasing force of the spring 24 and the fluid pressure from the downstream opening 20 side, and is in a closed position that closes the fluid passage 10. When the fluid pressure at the upstream opening 18 exceeds the combined force of the biasing force of the spring 24 and the fluid pressure at the downstream opening 20, the valve element 16 moves downstream from the valve seat surface 32 and is displaced to an open position that opens the fluid passage 10, as shown in FIG. 3 . This allows fluid to flow from the upstream opening 18 toward the downstream opening 20.

[0017] If the fluid pressure at the upstream opening 18 drops, for example, due to a cessation of fluid supply from the upstream opening 18, the valve disc 16 is pushed upstream by the biasing force of the spring 24 and the fluid pressure from the downstream opening 20, returning to the closed position shown in FIG. 1 and again closing the fluid passage 10. This prevents fluid from flowing back from the downstream opening 20 to the upstream opening 18. The force acting on the valve disc 16 from the spring 24 and the downstream fluid is concentrated on the contact portion 30, which is in contact with the valve seat surface 32. If the fluid pressure from the downstream side is within the specified range, the contact portion 30 of the valve disc 16 should not deform. However, if excessive fluid pressure that significantly exceeds this range acts on the valve disc 16 for some reason, the contact portion 30 of the valve disc 16 may deform. This causes the valve disc 16 to move further upstream from the closed position shown in FIG. 1. When the deformation of the valve disc 16 increases and the displacement of the valve disc 16 toward the upstream side exceeds a certain level, the reinforcing member 36 abuts against the locking surface 50 formed on the inner circumferential surface 12 of the flow path member 14, as shown in FIG. 4 . This locking surface 50 is formed radially inward at a position upstream of the valve seat surface 32. As described above, the reinforcing member 36 is formed of a metal material that is more rigid than the resin material of the valve disc 16. This prevents the reinforcing member 36 from deforming even when a force sufficient to deform the valve disc 16 is applied. This allows the reinforcing member 36 to support the valve disc 16 relative to the flow path member 14, preventing the valve disc 16 from further displacing upstream. In particular, when the reinforcing member 36 engages with the locking surface 50, the locking surface 50 blocks the fluid passage 10, preventing the resin material of the valve disc 16 from deforming upstream beyond the reinforcing member 36.

[0018] In this way, in the check valve 1, even if excessive fluid pressure acts from the downstream side in the closed state and deforms the valve disc 16, the reinforcing member 36, which is made of a highly rigid material, engages with the locking surface 50 of the flow path member 14 to support the valve disc 16, preventing further deformation and damage to the valve disc 16. This ensures that the backflow prevention function of the check valve 1 is not lost even when extremely large fluid pressure acts, and makes it possible to prevent high-pressure fluid from flowing back upstream. Furthermore, because the valve disc 16 can be made of a material with relatively low rigidity and high elasticity, high sealing performance can be achieved relatively easily, and the sound generated when the valve disc 16 collides can be reduced compared to when the valve disc 16 is made of a highly rigid metallic material.

[0019] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, the materials constituting the flow path member, reinforcing member, and valve body are not limited to the metal and resin materials described above. They can be made of other metal or resin materials taking into account the type of fluid, pressure, temperature, and other operating conditions. Furthermore, the flow path member and reinforcing member do not necessarily have to be made of metal. For example, if a fluid of not very high pressure flows through them, they can be made of a relatively rigid resin material, and the valve body can be made of a less rigid resin material or rubber material. In other words, the materials constituting each component can be selected appropriately according to the operating conditions, as long as the flow path member and reinforcing member are made of a material with higher rigidity than the valve body. Furthermore, the entire flow path member does not necessarily have to be made of a material with higher rigidity than the valve body. It is important that at least the portion where the engagement surface is formed is made of such a material. The check valve of the present invention can be used with various fluids, including gases such as oxygen and hydrogen, liquids such as water and chemicals, and gas-liquid mixtures. [Explanation of symbols]

[0020] 1. Check valve 10 Fluid passage 12 Inner surface 14 Flow path member 16 Valve body 18 Upstream opening 20 Downstream opening 22 Support member 24 Spring 26 Annular recess 28 Stop ring 30 Contact part 32 Valve seat surface 34 Upstream end 36 Reinforcement member 38 Main body 40 Male thread 42 Upstream end face 44 mounting holes 46 Female thread 48 Tool engagement part 50 Locking surface L Longitudinal axis

Claims

1. a flow path member having an inner circumferential surface that defines an upstream opening, a downstream opening, and a fluid passage extending from the upstream opening to the downstream opening, the inner circumferential surface having a valve seat surface and a locking surface that is located radially inward of the valve seat surface; a valve element disposed in the fluid passage so as to be displaceable between a closing position where the valve element engages with the valve seat surface to close the fluid passage and an opening position where the valve element moves away from the valve seat surface downstream to open the fluid passage; a reinforcing member disposed at an upstream end of the valve body; a spring that biases the valve body upstream; Equipped with At least a portion of the flow path member where the locking surface is formed and the reinforcing member are made of a material having a higher rigidity than the valve body, a check valve in which the valve body is brought to the closed position by the biasing force of the spring, and when the fluid pressure from the downstream opening is within a predetermined range, the reinforcing member does not engage with the locking surface, and when the fluid pressure from the downstream opening exceeds a predetermined magnitude, the valve body is displaced further upstream from the closed position while deforming the portion of the valve body that engages with the valve seat surface, and the reinforcing member engages with the locking surface to support the valve body against the flow path member.

2. 2. The check valve of claim 1, wherein the reinforcing member blocks the fluid passage at the locking surface when the reinforcing member engages the locking surface.

3. the valve body has a mounting hole extending downstream from a radial center position of an upstream end surface of the valve body, 3. The check valve according to claim 1, wherein the reinforcing member is inserted into the mounting hole and fixed to the valve body.

4. The check valve according to claim 1 , wherein the valve body is made of a resin material, and the flow path member and the reinforcing member are made of a metal material.

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