Rotary valve

Abstract

The present invention addresses the problem of reducing the possibility of fluid leakage to the downstream side when a flow path is completely closed. The rotary valve includes: a valve body through which a flow path of a fluid passes; a cock that is disposed in the flow path and that adjusts the flow rate of the fluid by rotating; and a cylindrical valve seat part which forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface of the cock. The valve seat portion includes: a cylindrical valve seat member in close contact with the valve seat surface; a cylindrical positioning member that has an overlapping portion that partially overlaps the valve seat member in a direction orthogonal to the flow direction of the flow path, is fixed to the valve body, and positions the valve seat member; and an annular sealing member that seals between the valve seat member and the overlapping portion. The valve seat portion has a structure such that, when the flow path is completely closed, the valve seat member is pressed against the valve seat surface with a greater force as the pressure difference between the pressure of the fluid in the portion of the flow path and the pressure of the fluid outside the valve seat portion is greater.

Description

Technical Field

[0001] The invention relates to a rotary valve. Background Art

[0002] Patent Document 1 discloses a rotary valve 36a comprising: a valve body 40 through which a fluid flows; a plug 50 disposed in the flow path and regulating the flow rate of the fluid by rotating, and having a valve seat surface for completely closing the flow path; and a cylindrical valve seat portion (72, 74, 80) forming a portion of the flow path and in close contact with the valve seat surface to completely close the flow path. The valve seat portion comprises: a cylindrical valve seat member 74 in close contact with the valve seat surface; a cylindrical positioning member 72 having an overlapping portion that partially overlaps with the valve seat member in a direction perpendicular to the flow direction of the flow path, and being fixed to the valve body to position the valve seat member; and an annular sealing member 80 that seals between the valve seat member and the overlapping portion.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent No. 5806871 Summary of the Invention

[0006] [Problems to be solved by the invention]

[0007] In the valve body described in Patent Document 1, for example, when the flow path is fully closed, the differential pressure between the fluid on the primary and secondary sides exerts a force on the valve seat member in a direction separating from the plug, thereby potentially causing fluid leakage when the flow path is fully closed. Furthermore, the valve seat member may deform due to, for example, the differential pressure between the inside and outside of the valve seat member, the heat of the fluid, and the like, potentially causing fluid leakage downstream when the flow path is fully closed.

[0008] An object of the present invention is to reduce the possibility of fluid leakage to the downstream side when a flow path is completely closed.

[0009] [Technical means to solve the problem]

[0010] (1) The rotary valve of the present invention includes: a valve body, through which a fluid flows; a plug, which is arranged in the flow path to adjust the flow rate of the fluid by rotating, and has a valve seat surface for completely closing the flow path; and a valve seat portion, which is cylindrical and forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface, the valve seat portion including: a cylindrical valve seat member in close contact with the valve seat surface; a cylindrical positioning member having an overlapping portion that partially overlaps with the valve seat member in a direction orthogonal to the flow direction of the flow path, and is fixed to the valve body and positions the valve seat member; and an annular sealing member that seals between the valve seat member and the overlapping portion, the valve seat portion having the following structure: when the flow path is completely closed, the greater the pressure difference between the pressure PA of the fluid in the part of the flow path and the pressure PB of the fluid outside the valve seat portion, the greater the force with which the valve seat member is pressed against the valve seat surface.

[0011] (2) The rotary valve of the present invention includes: a valve body, a flow path for a fluid to pass through; a plug, which is arranged in the flow path and adjusts the flow rate of the fluid by rotating, and has a valve seat surface for completely closing the flow path; and a valve seat portion, which is cylindrical and forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface, the valve seat portion including: a cylindrical valve seat member in close contact with the valve seat surface; a cylindrical positioning member having a repeated portion that partially overlaps with the valve seat member in a direction orthogonal to the flow direction of the flow path, and is fixed to the valve body and positions the valve seat member; and an annular sealing member that seals between the valve seat member and the repeated portion, the valve seat member surrounding the outer periphery of the repeated portion of the positioning member, the valve seat portion also including a reinforcing member, the reinforcing member being a cylindrical reinforcing member having an inner peripheral surface in contact with the outer peripheral surface of the valve seat member and being harder than the valve seat member.

[0012] [Effects of the Invention]

[0013] According to the invention (1), the greater the pressure difference between the pressure PA and the pressure PB, the greater the force with which the valve seat member is pressed against the valve seat surface. Therefore, the possibility of fluid leakage to the downstream side when the flow path is fully closed is reduced.

[0014] According to the invention of (2) above, deformation of the valve seat member is less likely to occur due to the reinforcement member, and the possibility of fluid leakage to the downstream side when the flow path is fully closed is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view of a rotary valve according to an embodiment of the present invention.

[0016] Figure 2 Therefore Figure 1 The cross section of the X portion surrounded by the dotted line is an enlarged end view of the end surface.

[0017] Figure 3 It is an enlarged end view showing a cross section of a rotary valve according to a modified example.

[0018] [Explanation of Symbols]

[0019] 10: Rotary valve

[0020] 20: Valve body

[0021] 21: Flange

[0022] 22: Flange

[0023] 23: Through hole

[0024] 24: Through hole

[0025] 31: Upper cover member

[0026] 31A: Through hole

[0027] 35: Valve shaft

[0028] 40: Support

[0029] 41: Lower cover member

[0030] 41A: concave part

[0031] 42: Shaft component

[0032] 50: cock

[0033] 51: Valve seat surface

[0034] 60: Valve seat

[0035] 61: Positioning components

[0036] 61A: concave part

[0037] 61B: Repeating part

[0038] 62: Valve seat component

[0039] 62A: Part 1

[0040] 62B: Part 2

[0041] 62C: Bevel

[0042] 62D: Slot

[0043] 63: Enhanced components

[0044] 63A: Main body

[0045] 63B: Extension

[0046] 64: Sealing component

[0047] 65: Elastomer

[0048] C: Rotation axis

[0049] D1: Point

[0050] D2: Point

[0051] PA: Pressure

[0052] PB: Pressure

[0053] R: flow path

[0054] R1: upstream flow path

[0055] R2: Downstream flow path

[0056] V: Face

[0057] W: Face

[0058] Z: Space DETAILED DESCRIPTION

[0059] The following describes a rotary valve 10 according to an embodiment of the present invention with reference to the accompanying drawings. Hereinafter, the flow direction of the fluid flowing through the flow path R within the rotary valve 10 will be referred to as the left-right direction. Specifically, the upstream side (also referred to as the primary side) will be referred to as the left, and the downstream side (also referred to as the secondary side) will be referred to as the right. Furthermore, the direction perpendicular to the left-right direction will be referred to as the up-down direction. These directions are provided for ease of explanation and do not limit the orientation of the rotary valve 10. In other words, the rotary valve 10 may be positioned in an up-down direction other than the vertical direction.

[0060] The rotary valve 10 includes a valve body 20 , an upper cover member 31 , a valve shaft 35 , a support portion 40 , a plug 50 , and a valve seat portion 60 .

[0061] The valve body 20 is formed into a hollow cylindrical shape. A stopcock 50 is disposed within the hollow portion, and a flow path R, consisting of an upstream (primary) flow path R1 and a downstream (secondary) flow path R2, is passed through the hollow portion. The valve body 20 includes flanges 21 and 22 at its left and right ends for connection to piping. The valve body 20 also includes through-holes 23 and 24 at its upper and lower portions, located in the center of the valve body 20 in the left-right direction.

[0062] The upper cover member 31 has its lower portion inserted into the through hole 23 and seals the through hole 23. The upper cover member 31 and the valve body 20 are interlocked, screwed, bonded, or welded to prevent the fluid flowing in the flow path R from leaking therebetween. The upper cover member 31 is formed in a cylindrical shape and has a through hole 31A that passes through in the up and down directions. The valve shaft 35 is inserted into the through hole 31A. A sealing member (not shown) such as an O-ring is provided between the upper cover member 31 and the valve shaft 35 to seal the gap so that the valve shaft 35 can rotate relative to the upper cover member 31.

[0063] A plug 50 is connected to the lower end of the valve shaft 35, and an electric or pneumatic operator (not shown) is connected to the upper end of the valve shaft 35. The operator rotates the plug 50 via the valve shaft 35. The rotation axis C of the valve shaft 35 and plug 50 is orthogonal to the axis A of the valve body 20 and the flow path R.

[0064] The support portion 40 supports the plug 50. The support portion 40 includes a lower cover member 41 and a shaft member 42. The lower cover member 41 inserts its upper portion into the through-hole 24 and covers the through-hole 24 from the lower side. The lower cover member 41 and the valve body 20 are fitted, screwed, bonded, or welded to prevent the fluid flowing in the flow path R from leaking therebetween. A recess 41A is formed in the upper portion of the lower cover member 41, and the shaft member 42 is inserted into the recess 41A in a rotatable manner. Thus, the lower cover member 41 supports the shaft member 42 so that it can rotate. The shaft member 42 supports the plug 50 by connecting its upper portion to the plug 50. The shaft member 42 is coaxially arranged with the valve shaft 35. The plug 50, which rotates via the valve shaft 35, rotates together with the shaft member 42. At this time, the lower cover member 41 does not rotate. Alternatively, the shaft member 42 may be fixed to the lower cover member 41 , and the cock 50 may be rotated relative to the shaft member 42 .

[0065] The plug 50 is formed by cutting away a portion of a spherical shell and has a roughly C-shaped cross-section. Rotating the plug 50 changes the opening of the flow path R, thereby regulating the flow rate of the fluid. The plug 50 has a spherical outer surface. This outer surface includes a valve seat surface 51 that contacts the valve seat portion 60 when the flow path R is fully closed. The plug 50 can also be spherical, with a through hole extending in the upstream and downstream directions (left-right directions) when the flow path R is fully opened.

[0066] The valve seat portion 60 is formed in an overall cylindrical shape, forming the upstream flow path R1 of the flow path R, and is in slidable, close contact with the outer surface of the plug 50. In particular, the valve seat portion 60 fully closes the flow path R by closely contacting the valve seat surface 51 of the plug 50 (the valve seat surface 51 seats on the valve seat portion 60). The valve seat portion 60, in close contact with the valve seat surface 51, seals against leakage of fluid from the upstream flow path R1 into the downstream flow path R2 when fully closed.

[0067] like Figure 2 As shown, the valve seat portion 60 includes: a positioning member 61, a valve seat member 62, a reinforcement member 63, a sealing member 64, and an elastic body 65 (in Figure 1 and Figure 2 (Simplified and illustrated in the figure).

[0068] The positioning member 61 is fixed to the valve body 20 and positions the valve seat member 62 and other components. The positioning member 61 is cylindrical. The outer circumferential surface of the upstream end of the positioning member 61 is fixed to the inner circumferential surface of the valve body 20. The two are fixed by fitting, screwing, bonding, or welding to prevent fluid leakage between them.

[0069] The positioning member 61 has an annular recess 61A on its outer peripheral surface that opens toward the downstream side (right side). An elastic body 65 including a spring is housed in the recess 61A. The elastic body 65 may also be an annular rubber or the like. The elastic body 65 is disposed between the positioning member 61 (more specifically, the bottom surface of the recess 61A) and the valve seat member 62 to apply force to the valve seat member 62. The positioning member 61 has a position on its downstream side that is in the upstream and downstream directions ( Figure 1 A cylindrical overlapping portion 61B partially overlaps with the valve seat member 62 in a direction orthogonal to the direction in which the axis A extends (the direction in which the rotation axis C extends).

[0070] The valve seat member 62 is a member that is in substantial contact with the outer surface of the plug 50 (particularly the valve seat surface 51) when the valve seat portion 60 is in close contact with the outer surface. The valve seat member 62 is formed into a cylindrical shape that surrounds the outer circumference of the overlapping portion 61B. The valve seat member 62 includes a first portion 62A located downstream and not overlapping with the overlapping portion 61B, and a second portion 62B located upstream and surrounding the overlapping portion 61B. The first portion 62A is thicker than the second portion 62B.

[0071] The inner circumferential end of the downstream end surface of the first portion 62A forms a dam-shaped sloped surface 62C. This sloped surface 62C is a chamfered circular ring inclined relative to a plane perpendicular to the left-right direction. This sloped surface 62C is in close contact with the outer surface of the plug 50, particularly the valve seat surface 51. The sloped surface 62C makes line contact with the outer surface of the plug 50, particularly the valve seat surface 51. This line contact is circular. This circular contact line is also referred to as a contact circle.

[0072] The second portion 62B of the valve seat member 62 includes an annular groove 62D opening into its inner circumference. An annular sealing member 64, such as an O-ring, is housed in the groove 62D. The sealing member 64 is sandwiched between the bottom surface of the groove 62D and the outer circumference of the overlapping portion 61B of the positioning member 61, thereby sealing the gap between the inner circumference of the sealing member 64 and the outer circumference of the overlapping portion 61B. The sealing member 64 is in line contact with the positioning member 61 or the valve seat member 62, forming a contact circle of this line contact.

[0073] The reinforcing member 63 is cylindrical and is configured to reinforce the valve seat member 62 by contacting its inner circumference with the outer circumference of the valve seat member 62. The valve seat member 62 is made of, for example, resin and is subject to deformation as described below. The reinforcing member 63 is provided to suppress such deformation. The reinforcing member 63 is made of, for example, metal, which is harder than the valve seat member 62.

[0074] The reinforcement member 63 includes a cylindrical main body 63A and an annular plate-shaped extension 63B that extends inward from the upstream end of the main body 63A. The reinforcement member 63 covers the valve seat member 62 from the upstream side. Specifically, the main body 63A covers the outer circumference of the valve seat member 62, and the extension 63B covers the upstream end surface (left surface) of the valve seat member 62. The main body 63A extends further toward the plug 50 (rightward) than the right end of the valve seat member 62, which is on the plug 50 side (see portion 63AA to the right of the dashed line).

[0075] The reinforcing member 63 and the valve seat member 62 are biased downstream, i.e., toward the plug 50, by the elastic body 65. More specifically, the elastic body 65 is sandwiched between the bottom surface of the recessed portion 61A of the positioning member 61 and the upstream side surface (left surface) of the extension 63B of the reinforcing member 63, biasing the reinforcing member 63 and the valve seat member 62 toward the plug 50. As a result, the elastic body 65 pushes the valve seat member 62 via the reinforcing member 63 (extension 63B), thereby pressing the plug 50.

[0076] In the structure of the rotary valve 10 as described above, the flow from the upstream to the Figure 1 The fluid in the flow path R shown flows into the downstream flow path R2 when the flow path is opened or closed. At this time, the fluid also flows into the space Z outside the valve seat portion 60. Therefore, this space is also included in the downstream flow path R2.

[0077] The valve seat portion 60 is formed as follows: when the flow path R is fully closed, the greater the pressure difference between the pressure PA of the flow path fluid in the valve seat portion 60 in the upstream flow path R1 and the pressure PB of the fluid outside the valve seat portion 60 (the space Z of the downstream flow path R2), the greater the force with which the valve seat member 62 is pressed against the valve seat surface 51 of the plug 50. Figure 2 To illustrate this point. In addition, Figure 2Point D1 indicates the contact position between the sealing member 64 and the overlapping portion 61B of the positioning member 61, and point D2 indicates the contact position between the inclined surface 62C of the valve seat member 62 and the valve seat surface 51 of the plug 50. The surfaces of the inclined surface 62C above and below point D2 are slightly separated from the valve seat surface 51, and pressure from the fluid is also applied thereto.

[0078] Pressure PA and pressure PB are applied to the combination of the valve seat member 62 and the sealing member 64. The pressure also includes the pressure applied to the valve seat member 62 via the reinforcing member 63. The pressure PA and pressure PB in the direction close to the plug 50 (i.e., the left-right direction) are offset by being applied to the surfaces of the combination of the valve seat member 62 and the sealing member 64 facing the opposite direction, but sometimes a part is not offset. For example, the same pressure PA is applied to the right surface of the sealing member 64 and the two surfaces of the valve seat member 62 facing the right surface (the surfaces located above the point D1 of the sealing member 64 and below the upper end of the sealing member 64), and the two are offset. The part that is not offset is the part between the point D1 and the point D2 in the up-down direction in the inclined surface 62C. Figure 2 The surface V shown by the thick line in FIG, and the opposite surface in Figure 2 The portion of surface W indicated by the bold line in FIG. A pressure PB is applied to surface V (more precisely, a surface projected onto a plane perpendicular to the left-right direction), and a pressure PA is applied to surface W. Therefore, among the forces applied to the valve seat member 62, a force F represented by the following formula (1) is applied as a force in the left-right direction (for details of this concept, see Patent Document 1). In the following formula (1), S1 is the area of ​​the contact circle (the circle passing through point D1) between the overlapping portion 61B of the sealing member 64 and the positioning member 61, and S2 is the area of ​​the contact circle (the circle passing through point D2) between the inclined surface 62C of the valve seat member 62 and the valve seat surface 51 of the plug 50. Furthermore, the force F has a positive value in the downstream direction, that is, in the direction on the plug 50 side.

[0079] F=(PA-PB)*(S1-S2) … (1)

[0080] Here, when the flow path R is completely closed, the pressure PA of the upstream flow path R1 increases, so PA>PB. Figure 1 and Figure 2As is clear, by providing the first portion 62A of the valve seat member 62 and the second portion 62B, which is thinner than the first portion 62A, the diameter of the contact circle passing through point D1 is larger than the diameter of the contact circle passing through point D2, achieving S1>S2. Therefore, force F always presses the valve seat member 62 against the valve seat surface 51 of the plug 50. Furthermore, while (S1-S2) remains constant, the differential pressure including (PA-PB) varies depending on changes in pressure PA and other factors. As the differential pressure (PA-PB) increases, F also increases.

[0081] As described above, the valve seat portion 60 of this embodiment can press the valve seat member 62 against the valve seat surface 51 of the plug 50 with greater force as the differential pressure between the pressures PA and PB increases when the flow path R is fully closed. This reduces the possibility of fluid leakage to the downstream side when the flow path is fully closed.

[0082] In addition, the structure of the valve seat portion 60 is not limited to this structure. For example, the valve seat portion 60 can be configured to apply a force including the force F of the above formula (1) to the valve seat member 62. The valve seat portion 60 can also be configured to be arranged on the downstream side of the cock 50, and to be set to PA<PB and S1<S2. For example, Figure 3 The structure shown (in Figure 3 , the same symbols are used for elements that are the same as or similar to those in the above description). Figure 3 50 is an enlarged cross-sectional view showing the structure on the downstream side of the cock 50. Figure 3 In the structure, the valve seat portion 60 seals the plug 50 from the downstream side. Pressure PA is the pressure of the fluid in a portion of the downstream flow path R2 formed by the inner wall of the valve seat portion 60, and pressure PB is the pressure of the fluid in the flow path space outside the valve seat portion 60 that returns to the upstream flow path R1. In the valve seat member 62, the first portion 62A is not thicker than the second portion 62B, and the diameter of the contact circle passing through point D1 is smaller than the diameter of the contact circle passing through point D2, so that S1<S2. The surface related to the above formula (1) is Figure 3 The surface depicted with a bold line in FIG. As another modified example, the reinforcing member 63 may be omitted. Furthermore, the overlapping portion 61B of the positioning member 61 may be disposed on the outer peripheral side of the valve seat member 62. Furthermore, the structure of the valve seat portion 60 may be such that the valve seat member 62 is pressed against the valve seat surface 51 of the plug 50 with a greater force as the differential pressure between the pressures PA and PB increases. The force may be a force other than the force calculated by equation (1).

[0083] Furthermore, the possibility of fluid leakage to the downstream side when the flow path is fully closed is further reduced by providing the elastic body 65 that presses the valve seat member 62 toward the cock 50. In addition, the above structure can also achieve the following effect: the elastic force of the elastic body 65 does not need to be increased.

[0084] Here, when pressure PA>pressure PB, the valve seat member 62 is deformed by a force in the direction of radial expansion, thereby reducing the tightness of the plug 50 and causing fluid leakage. The greater the pressure difference between pressure PA and pressure PB, the greater the deformation. In addition, when a resin material is used as the material of the valve seat member 62 in order to ensure tightness with the plug 50 and reduce the sliding resistance with the plug 50, and when the fluid is at a high temperature, the deformation also becomes larger. Therefore, valve seat leakage is likely to occur. In this embodiment, a reinforcing member 63 having an inner peripheral surface in contact with the outer peripheral surface of the valve seat member 62 and being harder than the valve seat member 62 is provided, so that the deformation is suppressed, thereby reducing the possibility of fluid leakage to the downstream side when the flow path is completely closed. In addition, if this effect is taken into consideration, the valve seat portion 60 may not be a structure in which the valve seat component 62 is pressed against the valve seat surface 51 of the plug 50 with greater force as the pressure difference between the pressure PA and the pressure PB increases when the flow path R is completely closed (for example, the elastic force of the elastomer 65 may be increased to cope with this).

[0085] The shape of the reinforcement member 63 is arbitrary, but as described above, the reinforcement member 63 extends further toward the plug 50 than the end of the valve seat member 62 on the plug 50 side. This makes the valve seat member 62 less likely to deform than if it were not extended, further reducing the possibility of fluid leakage to the downstream side when the flow path is fully closed. In addition, the elastic body 65 pushes the valve seat member 62 via the extension 63B of the reinforcement member 63, making it easier to position the reinforcement member 63.

[0086] While the present invention has been described above with reference to the embodiments and variations, the present invention is not limited to these embodiments and variations. For example, the present invention encompasses various modifications to the embodiments and variations that are understandable to those skilled in the art within the scope of the technical concept of the present invention. The various structures listed in the embodiments and variations may be combined as appropriate within the scope of non-inconsistency. Furthermore, omission of various structures is optional.

[0087] Supplementary Notes The configuration of the above-described embodiment and its modified examples are given as examples.

[0088] (Note 1)

[0089] A rotary valve comprising:

[0090] The valve body is used for the flow path of the fluid to pass through;

[0091] a cock disposed in the flow path and adjusting the flow rate of the fluid by rotating the cock, and having a valve seat surface for completely closing the flow path; and

[0092] The valve seat portion is cylindrical and forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface.

[0093] The valve seat portion includes:

[0094] a cylindrical valve seat member in close contact with the valve seat surface;

[0095] a cylindrical positioning member having an overlapping portion partially overlapping with the valve seat member in a direction perpendicular to the flow direction of the flow path, and being fixed to the valve body to position the valve seat member; and

[0096] An annular sealing member seals the valve seat member and the repeating portion.

[0097] The valve seat portion has the following structure: when the flow path is completely closed, the greater the pressure difference between the pressure PA of the fluid in the part of the flow path and the pressure PB of the fluid outside the valve seat portion, the greater the force with which the valve seat member is pressed against the valve seat surface.

[0098] (Note 2)

[0099] The rotary valve according to Supplementary Note 1, wherein

[0100] The force includes a force F represented by the following formula (A) when the direction toward the valve seat surface is positive,

[0101] The valve seat portion is formed to satisfy PA>PB and S1>S2, or PA<PB and S1<S2.

[0102] F=(PA-PB)*(S1-S2)…(A)

[0103] Wherein, S1 is the area of ​​the contact circle between the repeated portion and the sealing member, and S2 is the area of ​​the contact circle between the valve seat member and the valve seat surface.

[0104] (Note 3)

[0105] The rotary valve according to Supplementary Note 1 or 2, wherein

[0106] The valve seat portion is arranged on the upstream side of the stopcock.

[0107] (Note 4)

[0108] The rotary valve according to any one of Supplementary Notes 1 to 3, wherein

[0109] The valve seat portion further includes an elastic body, which is arranged between the valve seat member and the positioning member and presses the valve seat member toward the valve seat surface.

[0110] (Note 5)

[0111] The rotary valve according to any one of Supplementary Notes 1 to 4, wherein

[0112] The valve seat member surrounds the outer periphery of the repeated portion of the positioning member,

[0113] The valve seat portion further includes a reinforcing member. The reinforcing member is a cylindrical reinforcing member having an inner peripheral surface in contact with an outer peripheral surface of the valve seat member and being harder than the valve seat member.

[0114] (Note 6)

[0115] A rotary valve comprising:

[0116] The valve body is used for the flow path of the fluid to pass through;

[0117] a cock disposed in the flow path and adjusting the flow rate of the fluid by rotating the cock, and having a valve seat surface for completely closing the flow path; and

[0118] The valve seat portion is cylindrical and forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface.

[0119] The valve seat portion includes:

[0120] a cylindrical valve seat member in close contact with the valve seat surface;

[0121] a cylindrical positioning member having an overlapping portion partially overlapping with the valve seat member in a direction perpendicular to the flow direction of the flow path, and being fixed to the valve body to position the valve seat member; and

[0122] An annular sealing member seals the valve seat member and the repeating portion.

[0123] The valve seat member surrounds the outer periphery of the repeated portion of the positioning member,

[0124] The valve seat portion further includes a reinforcing member. The reinforcing member is a cylindrical reinforcing member having an inner peripheral surface in contact with an outer peripheral surface of the valve seat member and being harder than the valve seat member.

[0125] (Note 7)

[0126] The rotary valve according to Supplementary Note 5 or 6, wherein

[0127] The reinforcement member extends further toward the plug than an end portion of the valve seat member on the plug side.

[0128] (Note 8)

[0129] The rotary valve according to any one of Supplementary Notes 5 to 7, wherein

[0130] The valve seat portion further includes an elastic body, which is disposed between the valve seat member and the positioning member and presses the valve seat member toward the valve seat surface.

[0131] The reinforcing member includes: a cylindrical main body; and a protruding portion extending inward from an end portion of the main body on the side opposite to the cock side.

[0132] The elastic body presses the valve seat member via the protruding portion.

Claims

1. A rotary valve comprising: The valve body is used for the flow path of the fluid to pass through; a cock disposed in the flow path and adjusting the flow rate of the fluid by rotating the cock, and having a valve seat surface for completely closing the flow path; and The valve seat portion is cylindrical and forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface. The valve seat portion includes: a cylindrical valve seat member in close contact with the valve seat surface; a cylindrical positioning member having an overlapping portion partially overlapping with the valve seat member in a direction perpendicular to the flow direction of the flow path, and being fixed to the valve body to position the valve seat member; and An annular sealing member seals the valve seat member and the repeating portion. The valve seat portion has the following structure: when the flow path is completely closed, the greater the pressure difference between the pressure PA of the fluid in the part of the flow path and the pressure PB of the fluid outside the valve seat portion, the greater the force with which the valve seat member is pressed against the valve seat surface.

2. The rotary valve according to claim 1, wherein The force includes a force F represented by the following formula (A) when the direction toward the valve seat surface is positive, The valve seat portion is formed to satisfy PA>PB and S1>S2, or PA<PB and S1<S2. F=(PA-PB)*(S1-S2)…(A) in, S1 is the area of ​​the contact circle between the overlapping portion and the sealing member, and S2 is the area of ​​the contact circle between the valve seat member and the valve seat surface.

3. The rotary valve according to claim 1, wherein The valve seat portion is arranged on the upstream side of the stopcock.

4. The rotary valve according to claim 1, wherein The valve seat portion further includes an elastic body, which is arranged between the valve seat member and the positioning member and presses the valve seat member toward the valve seat surface.

5. The rotary valve according to claim 1, wherein The valve seat member surrounds the outer periphery of the repeated portion of the positioning member, The valve seat portion further includes a reinforcing member. The reinforcing member is a cylindrical reinforcing member having an inner peripheral surface in contact with an outer peripheral surface of the valve seat member and being harder than the valve seat member.

6. The rotary valve according to claim 5, wherein The reinforcement member extends further toward the plug than an end portion of the valve seat member on the plug side.

7. The rotary valve according to claim 5 or 6, wherein The valve seat portion further includes an elastic body, which is disposed between the valve seat member and the positioning member and presses the valve seat member toward the valve seat surface. The reinforcing member comprises: cylindrical body; and a protruding portion extending inward from an end portion of the main body on the side opposite to the tap side, The elastic body presses the valve seat member via the protruding portion.

8. A rotary valve comprising: The valve body is used for the flow path of the fluid to pass through; a cock disposed in the flow path and adjusting the flow rate of the fluid by rotating the cock, and having a valve seat surface for completely closing the flow path; and The valve seat portion is cylindrical and forms a part of the flow path and completely closes the flow path by being in close contact with the valve seat surface. The valve seat portion includes: a cylindrical valve seat member in close contact with the valve seat surface; a cylindrical positioning member having an overlapping portion partially overlapping with the valve seat member in a direction perpendicular to the flow direction of the flow path, and being fixed to the valve body to position the valve seat member; and An annular sealing member seals the valve seat member and the repeating portion. The valve seat member surrounds the outer periphery of the repeated portion of the positioning member, The valve seat portion further includes a reinforcing member. The reinforcing member is a cylindrical reinforcing member having an inner peripheral surface in contact with an outer peripheral surface of the valve seat member and being harder than the valve seat member.

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