JP2004257521A - Valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain reliability, pressure tightness, and durability of a seal, solve a problem of noise, and reduce the cost by reducing the number of parts and facilitate the manufacture. <P>SOLUTION: A valve has a valve seat 6 to open a valve port 5 at an inflow passage 2 side of a valve chamber 1 installed in a valve housing 4. In the valve chamber 1, there is provided with a valve element 7 to open the valve port 5 by leaving the valve seat 6 when fluid pressure from a flowout passage 3 into an inflow passage 2 is applied, and to close the valve seat 5 by moving to the valve seat direction 6 direction when fluid pressure from the outflow passage 3 into the inflow passage 2 is applied. The valve seat 6 is comprised of a first valve seat part 10 formed of elastic material and a second valve seat part 11 formed of non-elastic material. When the valve element 7 moves to the valve seat 6, at first the valve element 7 is brought in contact with the first valve seat part 10, and subsequently is brought in contact with the second valve seat part 11 by maintaining the contact state with the first valve seat part 10 and subjecting to the elastic deformation of the first valve seat part 10. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a valve that allows a fluid to flow only in one direction.
[0002]
[Prior art]
BACKGROUND ART Valves having a structure that prevents a backflow of a fluid and allows the fluid to flow only in one direction are widely used as check valves and vacuum break valves. There are various types of these valves depending on their structures, and suitable ones are selected and used according to the conditions of the equipment to be attached and the piping. Further, among the valve seats and valve bodies, there are those made of an elastic material such as rubber, which is called an elastic seal, and those made of an inelastic material such as metal, called a metal seal.
[0003]
When the seal by the valve seat or the valve body is an elastic seal, the sealing property is good, but there is a problem that the pressure resistance is low and the durability is lacking. On the other hand, when the metal seal is used, the pressure resistance and the durability are low. Although high, small dust is caught between the valve seat and the valve body.So-called dust bites easily impair the sealing performance and easily cause backflow. There were also problems.
[0004]
To solve these problems, a valve housing having an inflow passage formed on one side of a valve chamber provided therein and an outflow passage formed on the other side is provided with a valve port on the inflow passage side of the valve chamber. In the valve chamber, a shaft slidably supported by a guide supported by the inflow passage opening and a guide supported by the outflow passage opening is passed. A valve body constituted by a first valve body portion made of an elastic material like this and a second valve body portion made of a hard material such as metal is fixed, and in the valve seat, The first valve seat portion is in contact with the first valve body portion, and the second valve seat portion is in contact with the second valve body portion. When the fluid flows backward from the outflow passage to the inflow passage, First, the first valve body comes into contact with the first valve seat, and then the second valve body comes into contact with the second valve seat. The valve has been proposed (e.g., see Patent Document 1.).
[0005]
According to such a valve, the first valve body portion made of an elastic material such as rubber ensures the reliability of the seal even if there is a bite of dust, solves the problem of noise, and is made of a hard material such as metal. With the second valve body, pressure resistance and durability can be ensured.
[0006]
[Patent Document 1]
JP 2001-349454 A
[Problems to be solved by the invention]
However, it is composed of a first valve body made of an elastic material such as rubber and a second valve body made of a hard material such as metal, which are fixed to a shaft slidably supported by the guide. According to the valve having the valve body, the guide that slidably supports the shaft on which the valve body is fixed acts as a resistance to obstruct the flow of fluid, and the shaft on which the valve body is fixed. And the guide resistance that slidably supports this shaft hinders the movement of the valve body, and for example, when used as a vacuum break valve, the vacuum break pressure may lack stability. There is such a problem.
[0008]
An object of the present invention is to ensure the reliability, pressure resistance, and durability of a seal, to solve the problem of noise, to further reduce the number of parts, to facilitate manufacture, and to reduce the cost. Is to provide.
Another object of the present invention is to provide a valve capable of improving the flow with less resistance of the fluid.
Another object of the present invention is to provide a valve that can reduce the movement resistance of the valve element.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a valve housing provided with an inflow passage formed on one side and an outflow passage formed on the other side of the valve chamber. On the passage side, a valve seat having an opening is provided, and in the valve chamber, when receiving the fluid pressure from the inflow passage to the outflow passage, the valve moves to a side away from the valve seat to move away from the valve seat. A valve that has a valve body that moves in the valve seat direction and contacts a valve seat to close a valve port when receiving fluid pressure from the outflow passage to the inflow passage, wherein the valve seat includes: A first valve seat formed of an elastic material and a second valve seat formed of an inelastic material, wherein when the valve moves in the direction of the valve seat, the valve first moves to the first valve seat; Then, while maintaining the state of contact with the first valve seat portion, the first valve seat portion is elastically deformed and comes into contact with the second valve seat portion. Characterized in that it is configured urchin.
[0010]
With this configuration, when the valve element moves in the valve seat direction during the backflow of the fluid from the outflow passage to the inflow passage, the valve body first comes into contact with the first valve seat portion formed of an elastic material, and then the first Since the first valve seat is elastically deformed and abuts on the second valve seat made of an inelastic material while maintaining the contact state with the valve seat, the first valve seat made of an elastic material is formed. Due to the contact with the portion, the reliability of the seal is ensured even if there is a dust bite, and the impact of the contact of the first valve seat portion is cushioned by the elastic deformation of the first valve seat portion. Since it comes into contact with the rear second valve seat, generation of noise due to impact is prevented, and further, pressure contact and durability can be secured by contact with the second valve seat made of an inelastic material. Further, since the configuration is simple and the number of parts is small, the production is easy and the cost can be reduced.
[0011]
In the invention according to claim 2, the second valve seat portion constituting the valve seat according to claim 1 has a valve opening at a center, and a periphery of the valve opening is a contact seat surface, The first valve seat protrudes into the valve chamber on the outer periphery of the contact seating surface of the second valve seat so as to contact the valve body earlier than the contact seating surface of the second valve seat. It has an annular protrusion, and a contact seat surface is formed at the tip of the annular protrusion.
[0012]
With this configuration, when the valve body moves in the valve seat direction during the backflow of the fluid from the outflow passage to the inflow passage, the valve body firstly moves to the valve body before the contact seat surface of the second valve seat portion. The first valve is brought into contact with the first valve seat when the valve body comes into contact with the contact seat surface formed at the tip of the annular projection of the first valve seat protruding into the valve chamber so as to come into contact with the first valve seat. Elastic deformation of the seat can be reliably obtained.
[0013]
According to a third aspect of the present invention, in the second aspect, the abutment surface formed at the tip of the annular projection of the first valve seat portion constituting the valve seat is configured such that the valve element has an inflow passage. The valve seat is formed in a concave tapered shape having a gradually decreasing diameter in the direction in which the valve body moves toward the inflow side, and the contact seating surface of the second valve seat portion is formed in a planar shape orthogonal to the direction in which the valve body moves toward the inflow passage. The first valve is formed in a convex tapered shape that generally corresponds to the concave tapered abutment surface of the first valve seat portion. A first contact surface that contacts the seat, and a second contact that is formed in a planar shape corresponding to the planar contact seat surface of the second valve seat and contacts the second valve seat. Characterized by having a surface.
[0014]
With this configuration, when the fluid flows backward from the outflow passage to the inflow passage, the valve body moves in the valve seat direction, and the first abutting surface formed in the convex tapered shape of the valve body is formed by the first valve seat portion. When abutting against the contact seating surface formed in a concave tapered shape, the contact seating surface formed in a concave tapered shape is pushed outward in the outer peripheral direction by a first contact surface formed in a convex tapered shape, Due to this restoring force, the close contact between the first contact surface of the valve body and the contact seat surface of the first valve seat is increased, and the sealing performance is improved. The contact seating surface of the second valve seat is formed in a plane orthogonal to the direction in which the valve element moves toward the inflow passage, and the valve element has a planar shape of the second valve seat. Since the second valve seat portion has the second contact surface formed in a planar shape corresponding to the contact seat surface formed on the second valve seat, the contact surface of the second valve seat moves. Since the contact surface can be reliably received and the first valve seat portion made of the elastic material can be prevented from being deformed more than necessary, the pressure resistance and durability can be improved.
[0015]
According to a fourth aspect of the present invention, the valve body according to any one of the first to third aspects has a body portion, and a side surface of the body portion has a convex curved surface having a small diameter before and after the movement direction. It is characterized by being formed.
[0016]
With such a configuration, the body of the valve body that comes into contact with the inner wall of the valve chamber is in point contact, and the movement resistance of the valve body is small, and the movement is not caught, so that the smooth and stable movement of the valve body can be obtained. .
[0017]
According to a fifth aspect of the present invention, there is provided the valve chamber according to any one of the first to fourth aspects, wherein the valve chamber is provided with a wall that abuts a valve element that moves away from the valve seat and prevents further movement. The valve body provided in the valve chamber is formed with a fitting projection that is loosely fitted to a valve port that opens to the valve seat. A part of the tip is formed to have a length that stops in the valve port even if it moves until it comes into contact with the valve.
[0018]
With such a configuration, the fitting projection formed on the valve body is located in the valve opening that opens to the valve seat and cannot be removed. Therefore, even if the valve body is not supported by a shaft or the like in the valve chamber, the valve body can be moved in the valve seat direction. When the valve moves to the position, the valve body surely comes into contact with the valve seat to close the valve port.
[0019]
A sixth aspect of the present invention is characterized in that the valve housing according to any one of the first to fifth aspects is provided with a spring for urging the valve body in a valve seat direction.
[0020]
With this configuration, when the fluid is not flowing from the inflow passage side to the outflow passage side, the valve body is urged by the spring to abut the valve seat, and the valve opening that opens to the valve seat is in a closed state. It can be used not only as a check valve but also as a vacuum break valve.
[0021]
According to a seventh aspect of the present invention, in the first aspect of the present invention, the outer periphery of the second valve seat is screwed and attached to the inflow passage of the valve housing. And
[0022]
With such a configuration, the configuration is further simplified, and the number of parts is reduced, so that the manufacturing is facilitated and the cost can be further reduced.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 3 show an example of an embodiment of a valve according to the present invention. FIG. 1 is a longitudinal sectional view showing a state in which a flow path of the valve is open, and FIGS. It is a longitudinal cross-sectional view which shows the contact process of a valve body and a valve seat at the time of the backflow of the fluid to an inflow path.
[0024]
The valve according to the present embodiment is provided on the inflow passage 2 side of the valve chamber 1 of the cylindrical valve housing 4 in which the inflow passage 2 is formed on one side of the valve chamber 1 provided therein and the outflow passage 3 is formed on the other side. And a valve seat 6 having an opening 5, which moves in the valve chamber 1 away from the valve seat 6 when receiving fluid pressure from the inflow passage 2 to the outflow passage 3. The valve body 7 opens the valve port 5 to move in the direction of the valve seat 6 when receiving the fluid pressure from the outflow passage 3 to the inflow passage 2 and contacts the valve seat 6 to close the valve port 5. It has.
[0025]
On the inner peripheral surface of the inflow passage 2 of the valve housing 4, a female screw 8 screwed to the inflow-side piping is formed, and on the outer peripheral surface of the cylindrical portion forming the outflow passage 3 of the valve housing 4, A male screw 9 to be screwed is formed.
[0026]
The valve seat 6 includes a first valve seat 10 formed of an elastic material such as rubber and a second valve seat 11 formed of an inelastic material such as a metal. When the valve body 7 moves in the direction, the valve body 7 first comes into contact with the first valve seat 10, and then the elastic deformation of the first valve seat 10 is obtained while maintaining the contact state with the first valve seat 10. The two valve seats 11 are configured to come into contact with each other.
[0027]
More specifically, the second valve seat portion 11 that constitutes the valve seat 6 has a flow passage hole 13 that opens the valve port 5 in the center, and the periphery of the valve port 5 is a contact seat surface 12, The contact seat surface 12 is formed in a flat shape perpendicular to the direction in which the valve element 7 moves toward the inflow passage 2. The first valve seat 10 contacts the valve body 7 on the outer periphery of the contact seating surface 12 of the second valve seat 11 before the contact seating surface 12 of the second valve seat 11. The annular projection 14 projects into the valve chamber 1 so that a contact seat surface 15 is formed at the tip of the annular projection 14. The contact seating surface 15 formed at the tip of the annular projection 14 is formed in a concave tapered shape whose diameter gradually decreases in the direction in which the valve element 7 moves toward the inflow passage 2.
[0028]
In the present embodiment, the second valve seat portion 11 constituting the valve seat 6 comprises a base 17 having a male screw 16 formed therein which can be screwed into the female screw 8 formed on the inner peripheral surface of the inflow passage 2 of the valve housing 4. And a cylindrical portion 18 protruding from the base 17 toward the valve chamber 1 to form the valve port 5. The first valve seat 10 has a configuration in which the annular projection 14 is formed on one side surface of a disc-shaped base 20 having a hole 19 at the center thereof that can be fitted on the outer periphery of the cylindrical portion 18. ing. Then, the disc-shaped base 20 constituting the first valve seat portion 10 is fitted to the outer periphery of the cylindrical portion 18 formed on the base 17 constituting the second valve seat portion 11, and the first valve The seat 10 and the second valve seat 11 are integrally held.
[0029]
In mounting the valve seat 6 thus configured to the valve housing 4, the base 17 forming the second valve seat 11 with the first valve seat 10 facing the valve chamber 1 is attached to the valve housing 4. The female screw 8 is screwed into the female screw 8 using the female screw 8 that is screwed into the inflow-side pipe formed on the inner peripheral surface of the inflow passage 2. At this time, the valve chamber 1 is formed to have a smaller diameter than the inflow passage 2, and the outer peripheral portion of the disc-shaped base 20 constituting the first valve seat portion 10 is located between the inflow passage 2 and the valve chamber 1. The second valve seat portion 11 and the step portion 21 formed at the outer peripheral portion of the base 17 are fastened. Accordingly, the disc-shaped base 20 constituting the first valve seat portion 10 also functions as a sealing member for sealing between the valve seat 6 and the valve housing 4. Further, a seal ring 22 is mounted between the valve seat 6 and the valve housing 4.
[0030]
In addition, the valve body 7 that comes into contact with the valve seat 6 configured as described above has a body 23 having a predetermined length in the moving direction, and the body 23 contacts the valve seat 6. On the contact surface side, a first contact surface 24 formed in a convex tapered shape substantially corresponding to the contact seat surface 15 formed in a concave tapered shape of the first valve seat portion 10, and the second valve seat portion. 11 has a second contact surface 25 formed in a planar shape corresponding to the contact seat surface 12 formed in a planar shape, and the first contact surface 24 is provided on the first valve seat portion 10. The contact seat surface 15 and the second contact surface 25 contact the contact seat surface 12 of the second valve seat 11.
[0031]
The body 23 of the valve body 7 is formed to have a slightly smaller diameter than the inner diameter of the valve chamber 1, and the side surface 26 is formed to have a convex curved surface having a small diameter before and after the moving direction. The side surface 26 of the body 23 is supported by point contact with the inner wall of the valve chamber 1. Further, in the body portion 23, communication grooves 27 communicating the inflow passage 2 side and the outflow passage 3 side in the valve chamber 1 are provided at a plurality of circumferential positions.
[0032]
Further, a wall 28 is formed in the valve chamber 1 which accommodates the valve element 7 so as to be movable so that the valve element 7 moving away from the valve seat 6 is brought into contact with the valve element 7 to prevent further movement. The length of the body 23 constituting the valve body 7 in the moving direction is different from the valve chamber 1 when the valve body 7 moves away from the valve seat 6 and comes into contact with the wall 28. The length is set such that a space necessary for the flow of the fluid can be secured between the valve body 7 and the valve seat 6.
[0033]
Further, on the valve body 7 provided in the valve chamber 1, a fitting protrusion 29 is formed on the contact surface side with the valve seat 6 so as to be loosely fitted into the valve port 5 opened in the valve seat 6. The fitting projection 29 is formed to have such a length that a part of the tip thereof stops in the valve port 5 even when the valve element 7 moves until it comes into contact with the wall 28 of the valve chamber 1. The fitting projection 29 has a tapered guide surface 30 whose base portion has substantially the same diameter as the inner diameter of the valve port 5 and gradually decreases in diameter toward the distal end. The first contact surface 24 of the valve body 7 is guided by the guide surface 30 of the fitting projection 29 that moves to the back in the valve port 5 when the first valve seat portion of the valve seat 6 moves. The contact seat surface 15 and the second contact surface 25 of the valve seat 10 surely contact the contact seat surface 12 of the second valve seat portion 11 of the valve seat 6.
[0034]
A spring 31 is provided in the valve housing 4 between the outflow passage 3 and the valve chamber 1 to bias the valve body 7 in the direction of the valve seat 6. The resilience of the spring 31 may be weak enough to keep the valve body 7 in contact with the valve seat 6, but is not particularly limited and is appropriately selected depending on the application. The spring 31 is not necessarily required, for example, when the valve according to the present invention is used as a check valve, but is indispensable when used as a vacuum break valve.
[0035]
When the fluid flows from the inflow passage 2 to the outflow passage 3, the valve configured as described above moves in a direction away from the valve seat 6 by being pushed by the fluid, and the valve port is opened. 5, the fluid flows from the inflow passage 2 to the outflow passage 3. Conversely, when the fluid flows backward from the outflow passage 3 to the inflow passage 2, the valve body 7 is pushed by the backflowed fluid and moves toward the valve seat 6, and the first contact surface 24 of the valve body 7 first The first contact surface 15 of the first valve seat 10 made of an elastic material contacts the contact surface 15, and then the contact state between the first contact surface 24 and the contact surface 15 of the first valve seat 10 is maintained. The second contact surface 25 of the valve body 7 comes into contact with the contact seat surface 12 of the second valve seat 11 by obtaining the elastic deformation of the first valve seat 10 as it is. At this time, since the contact seating surface 15 of the first valve seat portion 10 with which the first contact surface 24 of the valve body 7 comes into contact is formed at the tip of the annular projection 14, the valve body 7 is in the first position. Elastic deformation of the first valve seat 10 when it comes into contact with the valve seat 10 can be reliably obtained.
[0036]
In the contact between the first contact surface 24 of the valve element 7 and the contact seat surface 15 of the first valve seat 10, the contact seat surface 15 of the first valve seat 10 is The first contact surface 24 of the valve element 7 is formed in a convex taper shape generally corresponding to the contact seat surface 15. Therefore, when the first contact surface 24 comes into contact with the contact seat surface 15 of the first valve seat portion 10, the contact seat surface 15 formed in a concave tapered shape is formed in a convex tapered shape. The first contact surface 24 pushes and expands in the outer peripheral direction, and the restoring force increases the adhesion between the first contact surface 24 of the valve body 7 and the contact seat surface 15 of the first valve seat portion 10, and seals. Thus, even if there is dust between the first contact surface 24 and the contact seat surface 15, the reliability of the seal can be ensured and the fluid leakage can be reliably prevented.
[0037]
The impact of the contact of the first valve seat portion 10 is buffered by the elastic deformation of the first valve seat portion 10 and the valve body 7 contacts the second valve seat portion 11 thereafter. Is prevented.
[0038]
In the contact between the second contact surface 25 of the valve element 7 and the contact seat surface 12 of the second valve seat 11, the contact seat surface 12 of the second valve seat 11 is The second contact surface 25 of the valve element 7 is formed in a planar shape corresponding to the contact seat surface 12 of the second valve seat 11. As a result, the contact seating surface 12 of the second valve seat portion 11 can reliably receive the second contacting surface 25 of the moving valve element 7, and the first contacting surface 25 made of the elastic material can be received. Unnecessary deformation of the valve seat 10 can be prevented, so that pressure resistance and durability can be improved.
[0039]
In this example, the valve element 7 has a body 23 having a predetermined length in the movement direction, and the body 23 is formed to have a slightly smaller diameter than the inner diameter of the valve chamber 1. The side surface 26 is formed as a convex curved surface having a small diameter in the front and rear directions of movement, and the body portion 23 is configured such that the side surface 26 is supported on the inner wall of the valve chamber 1 by point contact. Therefore, the movement resistance of the valve body 7 is small, and the movement is not caught, so that the valve body 7 can move smoothly and stably. In particular, when used as a vacuum breaking valve, the vacuum breaking pressure becomes stable. .
[0040]
Further, in the present embodiment, the valve chamber 1 that movably accommodates the valve element 7 is provided with a wall 28 that abuts the valve element 7 that moves away from the valve seat 6 and prevents further movement. In the valve body 7 provided in the valve chamber 1, a fitting protrusion 29 is formed on the contact surface side with the valve seat 6 so as to be loosely fitted into the valve port 5 opened in the valve seat 6. The fitting projection 29 is formed to have a length such that a part of the tip thereof stops in the valve port 5 even when the valve body 7 moves until it comes into contact with the wall 28 of the valve chamber 1. Therefore, the fitting projection 29 formed on the valve element 7 is always located in the valve port 5 opening to the valve seat 6 and does not come off. Therefore, even if the valve element 7 is not supported by a shaft or the like in the valve chamber 1, When the valve element 7 moves in the direction of the valve seat 6, the valve element 7 can reliably contact the valve seat 6 to close the valve port 5. Further, as described above, since there is no need for a shaft or the like for supporting the valve element 7, there is no movement resistance due to friction, and the vacuum breaking pressure when used as the vacuum breaking valve can be further stabilized. It is possible to obtain a good flow with low fluid resistance.
[0041]
The fitting protrusion 29 has a tapered guide surface 30 having a base portion having substantially the same diameter as the inner diameter of the valve port 5 and gradually decreasing in diameter toward the distal end. When moved, the first contact surface 24 of the valve body 7 is guided by the guide surface 30 of the fitting protrusion 29 that moves to the back in the valve port 5, and the first valve seat portion 10 of the valve seat 6. The contact seat surface 15 and the second contact surface 25 of the valve seat 6 surely contact the contact seat surface 12 of the second valve seat portion 11 of the valve seat 6, so that the valve body 7 moves smoothly. And seal integrity.
[0042]
Furthermore, the valve according to the present invention has a small number of parts as described above, and the valve seat 6 is attached to the valve housing 4 by turning the first valve seat 10 toward the valve chamber 1 side. The base 17 constituting the seat portion 11 is attached by being screwed to the female screw 8 using a female screw 8 that is screwed to an inflow-side pipe formed on the inner peripheral surface of the inflow passage 2 of the valve housing 4. Therefore, the female screw 8 is used for both the connection of the inflow-side piping and the screwing of the base 17 constituting the second valve seat portion 11, whereby not only the number of parts can be reduced, but also the manufacturing becomes easy and the cost is reduced. I can do it.
[0043]
【The invention's effect】
As described above, according to the valve of the present invention, the reliability, pressure resistance, and durability of the seal are ensured, and the noise problem is solved. In addition, since the movement resistance of the valve body can be reduced, a stable vacuum breaking pressure can be obtained, particularly when used as a vacuum breaking valve.
[Brief description of the drawings]
FIG. 1 is an example of an embodiment of a valve according to the present invention, and is a longitudinal sectional view showing a state where a flow path is open when a fluid flows in a forward direction.
FIG. 2 is a longitudinal sectional view showing a contact process between a valve body and a valve seat when a fluid flows backward from an outflow passage to an inflow passage.
FIG. 3 is a longitudinal sectional view showing a contact process between a valve body and a valve seat when a fluid flows backward from an outflow passage to an inflow passage.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 valve chamber 2 inflow passage 3 outflow passage 4 valve housing 5 valve opening 6 valve seat 7 valve body 8 female screw 9 male screw 10 first valve seat portion 11 second valve seat portion 12 contact seating surface 13 flow passage hole 14 annular protrusion 15 Contact seating surface 16 Male screw 17 Base 18 Cylindrical portion 19 Hole 20 Disc-shaped base 21 Step 22 Seal ring 23 Body 24 First contact surface 25 Second contact surface 26 Side surface 27 Communication groove 28 Wall 29 Fitting Projection 30 Guide surface 31 Spring

Claims (7)

A valve housing having an inflow passage formed on one side of the valve chamber provided therein and an outflow passage formed on the other side, the valve housing having a valve seat having an opening on the inflow passage side of the valve chamber; In the room, when receiving fluid pressure from the inflow passage to the outflow passage, the chamber moved to a side away from the valve seat to open the valve port, and received fluid pressure from the outflow passage to the inflow passage. When the valve includes a valve body that moves in the valve seat direction and abuts on the valve seat to close the valve port,
The valve seat includes a first valve seat portion made of an elastic material and a second valve seat portion made of an inelastic material. The first valve seat is configured to be brought into contact with the first valve seat, and then to be brought into elastic contact with the second valve seat while maintaining the contact state with the first valve seat. A valve characterized by the following. The second valve seat that constitutes the valve seat has a valve opening at the center, the periphery of the valve opening is used as a contact seat surface, and the first valve seat is a contact opening of the second valve seat. On the outer periphery of the seating surface, there is provided an annular projection that projects into the valve chamber so as to contact the valve body before the abutting seating surface of the second valve seat, and abuts on the tip of the annular projection. The valve according to claim 1, wherein a seat surface is formed. The contact seating surface formed at the tip of the annular projection of the first valve seat portion constituting the valve seat has a concave tapered shape in which the diameter gradually decreases in the direction in which the valve element moves toward the inflow passage. The contact seat surface of the second valve seat portion is formed in a planar shape orthogonal to the direction in which the valve element moves toward the inflow passage,
Further, the valve body that abuts on the valve seat abuts on the first valve seat portion that is formed in a convex tapered shape substantially corresponding to the contact seat surface that is formed in a concave tapered shape of the first valve seat portion. A first contact surface in contact with the second valve seat, and a second contact surface formed in a planar shape corresponding to the planar contact seat in the second valve seat and in contact with the second valve seat; The valve according to claim 2, wherein the valve is provided. The valve according to any one of claims 1 to 3, wherein the valve body has a body portion, and a side surface of the body portion is formed as a convex curved surface having a small diameter before and after the movement direction. . A wall is formed in the valve chamber for abutting a valve body moving away from the valve seat to prevent further movement, and the valve body provided in the valve chamber has an opening in the valve seat. A fitting projection that loosely fits into the valve port is formed, and a part of the tip of the fitting projection stops in the valve port even when the valve body moves until it comes into contact with the wall of the valve chamber. The valve according to any one of claims 1 to 4, wherein the valve is formed to have a length. The valve according to any one of claims 1 to 5, wherein the valve housing is provided with a spring for urging the valve body in a valve seat direction. The valve according to any one of claims 1 to 6, wherein an outer periphery of the second valve seat is screwed into the inflow passage of the valve housing.

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