JP2007182921A - Valve seat and ball valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve seat for a ball valve which prevents a sealing failure from being caused due to dimensional errors of components, and also to provide a structure of a ball valve. <P>SOLUTION: A valve seat 7 for a ball valve comprises: a substantially cylindrical and elastic seal member 13 which has a seal flow passage 18 passing through thereinside and keeps one end and the other abutted on a valve element 8 and a housing 6 respectively; and a member 14 with high rigidity including an outer peripheral part 27 surrounding the outer periphery of the seal member 13 and controlling ends 28, 29 which are inwardly extended from both ends of the outer peripheral part 27 and which sandwich outer edges in both ends of the seal member 13 from both sides thereof. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a valve seat for a ball valve and a ball valve.

  Generally, an annular or cylindrical valve seat having a flow path is disposed in a ball valve in order to seal between a housing and a valve body. The conventional ball valve is designed so that the valve seat is pressed against the housing and the valve body by the reaction force of elastic deformation while the valve seat is sandwiched between the valve body and the housing in the flow direction and compressed by a certain amount. Is done.

  Even if the valve seat is strongly sandwiched, the diameter of the valve seat increases so as to escape from the spherical valve body. In addition, when the fluid pressure is applied, the valve seat is expanded in diameter and the sealing strength is lowered. For this reason, the range of the appropriate compression ratio of the valve seat is very narrow. For example, in a cylindrical rubber valve seat having an inner diameter of 6 mm, an outer diameter of 12 mm, and a length of 8 mm in the flow path direction, an optimal sealing state can be obtained with 0.8 mm (10%) compression in the length direction. When designed, the allowable lengthwise compression error, i.e., the distance tolerance between the valve body and the housing, is only 0.3 mm. For this reason, the conventional valve seat has a problem that a sealing failure may occur due to a dimensional error caused by processing accuracy of the components of the ball valve.

  In view of the above problems, an object of the present invention is to provide a valve seat for a ball valve and a ball valve structure in which a seal failure is unlikely to occur due to a dimensional error of parts.

  In order to solve the above-described problems, a valve seat for a ball valve according to the present invention has a substantially cylindrical elastic member having a seal flow path penetrating the inside thereof, one end abutting against a valve body and the other end abutting against a housing. A rigid member having an outer peripheral portion surrounding the outer periphery of the seal member, and a regulating end portion that extends inward from both ends of the outer peripheral portion and sandwiches the outer edge portions of both ends of the seal member from both sides. It shall consist of members.

  According to this structure, the rigid member prevents the diameter of the seal member from expanding due to compression or fluid pressure between the valve body and the housing, and prevents the seal member from escaping from the valve body. As a result, good sealing performance can be obtained from a state in which the compression rate of the sealing member is low, and an appropriate seal can be obtained in a wide range of the distance between the valve body and the housing.

  Moreover, the valve seat of this invention WHEREIN: The both ends of the said sealing member may protrude the inner edge part in the flow direction of the said seal flow path.

  According to this configuration, the valve body and the housing can be brought into contact with both ends of the seal member without interfering with the restriction end portion even if the thickness of the restriction end portion is increased so as to obtain sufficient strength. .

  Moreover, the valve seat of this invention WHEREIN: The said control edge part by the side of the said valve body may closely_contact | adhere to the outer periphery of the said inner edge part which the said valve body side protruded of the said sealing member.

  According to this configuration, the inner surface of the seal that receives pressure in the expanding direction is pressed against the spherical surface of the valve body so as to be surrounded by the regulating end so as not to expand in the radial direction. The contact pressure with the body can be increased.

  In the valve seat of the present invention, an inner diameter of the restriction end on the valve body side may be smaller than an inner diameter of the restriction end on the housing side.

  According to this configuration, the protrusion on the valve body side end of the seal member is formed thin in the radial direction and is regulated from the outside by the regulating end, so that the sealing performance is easily impaired due to the diameter expansion. The part can be made more difficult to expand.

  Moreover, the valve seat of this invention WHEREIN: The said inner edge part by the side of the said housing of the said sealing member may protrude in the said rigid member housing side.

  According to this configuration, by projecting the end of the seal member on the housing side, the seal member can be compressed in the flow path direction even when contacting the flat housing, and the distance between the valve body and the housing Can be absorbed.

  The ball valve according to the present invention includes a valve seat having an inner edge protruding toward the rigid member housing, the housing having a seal surface that abuts the seal member, and the seal surface is recessed inside. The taper portion and a flat portion perpendicular to the seal flow path formed inside the taper portion.

  According to this configuration, if the end of the seal member on the housing side attempts to expand the diameter, the seal member comes into contact with the tapered portion to improve the sealing performance. Further, the internal pressure that pushes the seal member in the closed state of the ball valve is reduced when the valve is opened even slightly, and the compressive force in the flow direction of the seal member by the taper portion is reduced. Thereby, the friction between the valve body and the seal member is reduced, and the rotation of the valve body is facilitated.

  As described above, according to the present invention, the gap between the housing and the valve body is sealed by the elastic seal member and the rigid member that prevents the diameter of the seal member from expanding. Error is large and seal failure is unlikely to occur.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows a ball valve built-in pipe joint 1 according to an embodiment of the present invention. The pipe joint 1 includes a socket 2 and a plug 3 that can be connected to and disconnected from each other.

  The socket 2 includes a housing 4 and a sleeve 5 slidably provided on the outer periphery of the housing 4.

  The housing 4 is connected to the inflow portion 6 to which the upstream pipe line for supplying fluid is connected, the inflow portion 6, the accommodating portion 9 that accommodates the valve seat 7 and the valve body 8, and the accommodating portion 9. The coupling part 10 is made.

  The plug 3 includes an insertion portion 11 that is inserted into the coupling portion 10 and a nut portion 12 that is formed with a screw to which a downstream pipe line that receives fluid is connected.

  The valve seat 7 includes a rubber seal member 13 having elasticity and a metal rigid member 14 having high rigidity.

  The valve body 8 is supported in the accommodating portion 9 so as to be rotatable about the rotation shaft 15, and a drive member 16 is attached at a position eccentric from the rotation shaft 15. The drive member 16 is locked to a drive ring 17 fixed to the inner surface of the sleeve 5, and the sliding of the sleeve 5 can be converted into the rotation of the valve body 8.

  The inflow part 6 of the housing 4 is provided with a fluid inflow path 18, the seal member 13 of the valve seat 7 is provided with a seal flow path 19 communicating with the inflow path 18, and the valve body 8 has a valve body A movable channel 20 that can communicate with the seal channel 19 is provided at an angle of 8, and an outflow channel 21 that can communicate with the movable channel 20 is provided in the insertion portion 11 of the plug 3.

  One end of the valve seat 7 abuts on a seal surface 22 formed in the inflow portion 6 of the housing 4, and the other end abuts on a spherical outer surface of the valve body 8.

  Further, FIG. 2 shows the inflow portion 6, the valve seat 7 and the valve body 8 in detail. The sealing surface 22 has a flat surface portion 23 that is a flat surface formed in an annular shape perpendicular to the introduction path 15 and the sealing flow channel 16, and a tapered shape that is formed around the flat surface portion 23 and that is recessed toward the inner flat surface portion 23. The taper portion 24 is formed.

  The seal member 13 is formed in a substantially short cylindrical shape, the inner edge portion at the end portion on the inflow portion 6 side protrudes to form the inflow passage seal portion 25, and the inner edge portion at the end portion on the valve body 8 side protrudes to form the valve A body seal portion 26 is formed.

  The rigid member 14 is inward from the end portion of the outer peripheral portion 27 so as to cover a cylindrical outer peripheral portion 27 that tightly surrounds the outer periphery of the seal member 13 and an outer edge portion of the end portion on the inflow portion 6 side of the seal member 13. It has the 1st control end part 28 extended, and the 2nd control end part 29 extended inward from the edge part of the outer peripheral part 27 so that the outer edge part of the edge part by the side of the valve body 8 of the sealing member 13 may be covered.

  The first restriction end portion 28 and the second restriction end portion 29 are in close contact with the seal member 13 so as to sandwich the outer peripheral portions at both ends of the seal member 13. The first restriction end 28 has a larger inner diameter than the second restriction end 29, and the second restriction end 29 is in close contact with the outer periphery of the valve body seal portion 26 of the seal member 7, whereas the first restriction end 28 The end portion 28 has a slight gap between the end portion 28 and the inflow path seal portion 25 of the seal member 7. The inflow path seal portion 25 further protrudes from the first restriction end portion 28.

Then, the effect | action and effect of the pipe joint 1 which consists of the above structure are demonstrated.
In the pipe joint 1, the valve seat 8 is pressed against the seal surface 22 by the valve body 8 by tightening the housing portion 9 against the inflow portion 6. The seal member 13 of the valve seat 7 is elastically deformed and maintains a close contact state with the seal surface 22 and the valve body 8 by the reaction force, and seals between the inflow portion 6 and the valve body 8.

  When the accommodating portion 9 is tightened with respect to the inflow portion 6, the seal member 13 is compressed in the flow path direction between the seal surface 22 and the valve body 8. At this time, the seal member 13 cannot be expanded in diameter by the outer peripheral portion 27 of the rigid member 14 surrounding the outer periphery, and the compression in the flow channel direction by the inflow portion 6 and the valve body 8 is expanded in the radial direction to relieve. I can't. For this reason, the seal member 13 absorbs most of the compression in the flow path direction by deformation in the flow path direction, and generates a large reaction force in the flow path direction.

  Moreover, although the pressure of the fluid in the seal flow path 19 acts in the direction of expanding the diameter of the seal member 13, the outer periphery of the seal member 13 cannot be expanded in the radial direction by the outer peripheral portion 27, so that only the inner periphery. The diameter is expanded and the compressive force in the radial direction is extended in the direction of the flow path to relax. For this reason, the fluid pressure also generates a reaction force in the flow path direction of the seal member 7.

  Thus, since the seal member 13 generates a large reaction force in the flow path direction, even if the distance between the seal surface 22 and the valve body 8 varies, the seal member 13 is applied to the seal surface 22 and the valve body 8. It can be tightly intimate and can exhibit sufficient sealing properties.

  The inflow path seal portion 25 of the seal member 13 first comes into contact with the flat portion 23 of the contact surface 22 formed in the inflow portion 6 of the housing 4. The inflow path seal portion 25 is crushed and expanded in diameter when strongly pressed, and the outer portion abuts against the tapered portion 24 to improve the sealing performance between the inflow path 18 and the valve seat 7. Moreover, since the fluid pressure acts in a direction in which the diameter of the inflow path seal portion 25 is increased, the sealing performance is enhanced even by the fluid pressure. Further, since the taper portion 24 abuts the inflow passage seal portion 25 to suppress the radial deformation of the inflow passage seal portion 25, the compressive force of the seal member 13 is not released in the radial direction but in the flow passage direction. It also has an effect of acting.

  The valve body 8 has a substantially spherical shape, and a portion inclined with respect to the flow path direction is in contact with the inner edge of the valve body seal portion 29. For this reason, the valve body 8 also exerts a pressure contact force in the direction of expanding the diameter of the valve body seal portion 26. However, the valve body seal portion 26 of the seal member 7 is completely surrounded by the second restricting end portion 29 and cannot expand in the radial direction. Thereby, the pressure contact force of the valve body 8 acts as a force for compressing the seal member 13 in the flow path direction.

  In the present embodiment, for example, the seal member 7 is made of rubber having an inner diameter of 6 mm, an outer diameter of 12 mm, and a length in the flow path direction (distance between the tip of the inflow path seal portion 25 and the tip of the valve body seal portion 26) of 8 mm. When designed so as to obtain an optimum seal state with 0.8 mm (10%) compression in the vertical direction, an allowable compression error in the length direction, that is, between the seal surface 22 and the valve body 8. The tolerance of the distance is about 1 mm, which is a range that can be sufficiently achieved by normal machining accuracy.

Sectional drawing of the pipe joint of embodiment of this invention. The partial exploded sectional view of the pipe joint of Drawing 1.

Explanation of symbols

1 Fitting (Built-in ball valve)
4 Housing 6 Inflow section (housing)
7 Valve seat 8 Valve body 13 Seal member 14 Rigid member 18 Inflow path 19 Seal flow path 20 Movable flow path 22 Seal surface 23 Planar part 24 Taper part 25 Inflow path seal part (inner edge part)
26 Valve body seal (inner edge)
27 Outer peripheral portion 28 First regulating end portion 29 Second regulating end portion

Claims (6)

A seal member having a substantially cylindrical shape having a seal flow path penetrating through the inside, one end of which contacts the valve body, and the other end contacts the housing;
A high-rigidity rigid member having an outer peripheral portion that surrounds an outer periphery of the seal member and a regulating end portion that extends inward from both ends of the outer peripheral portion and sandwiches outer edge portions at both ends of the seal member from both sides. Characteristic valve seat for ball valve.   2. The valve seat according to claim 1, wherein inner ends of both ends of the seal member protrude in a flow direction of the seal flow path.   3. The valve seat according to claim 2, wherein the regulating end portion on the valve body side is in close contact with an outer periphery of the protruding inner edge portion of the seal member on the valve body side.   4. The valve seat according to claim 3, wherein an inner diameter of the restriction end on the valve body side is smaller than an inner diameter of the restriction end on the housing side.   The valve seat according to any one of claims 2 to 4, wherein the inner edge portion of the seal member on the housing side protrudes toward the housing side from the rigid member. The valve seat according to claim 5,
The housing has a seal surface that contacts the seal member;
2. The ball valve according to claim 1, wherein the sealing surface includes a tapered portion that is recessed inside, and a flat portion that is formed inside the tapered portion and is perpendicular to the sealing flow path.

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