JP4463631B2 - Valve seat structure - Google Patents

Description

  The present invention relates to a valve seat structure of a valve, and relates to a valve seat structure suitable for a valve seat of a rotary valve having an inner seal structure or a ball valve or a butterfly valve having an outer seal structure.

  Conventionally, there has been a valve seat structure applied to the eccentric inner surface seal valve shown in FIG. The valve seat structure of this valve has a concave spherical shape formed on the back surface of the valve body 4 and the valve box side seat portion 3 that projects out of the diameter near the outlet 2a of the valve sleeve 2 inserted into the valve box 1. The valve body side seat portion 5 is provided with an elastic sealing material 7 made of hard rubber and fitted on a flange portion 6 that is formed by projecting outward in the vicinity of the outlet 2a of the valve sleeve 2. The valve body 4 is attached to the valve box sleeve 2 so as to be rotatable about a position eccentric with respect to the outlet 2a of the valve box sleeve 2. Therefore, the closed state of the valve body 4 shown by the solid line is obtained by bringing the concave spherical valve body side seat portion 5 into close contact with the elastic sealing material 7 and closing the outlet 2 a of the valve box sleeve 2 with the valve body 4. In this closed state, for example, the powder dropped from the inlet 2b of the valve box sleeve 2 that functions as the inlet of the valve box 1 is the inner surface of the valve body 4, that is, the upper surface of the concave spherical valve body side seat portion 5. It is deposited on. Then, as shown by a two-dot chain line in FIG. 6, when the valve body 4 is rotated 90 degrees and the outlet 2 a of the valve box sleeve 2 is opened, the valve body 4 is deposited on the inner surface of the valve body 4. The powder falls from the outlet 2a (Patent Document 1).

  On the other hand, as a valve seat structure of another valve, there is one applied to the butterfly valve shown in FIG. The valve seat structure of this valve has a valve seat body 9 made of a metal plate having a substantially L-shaped cross section with a base portion 9a attached to the valve box 8, and the bent side of the valve seat body 9 is connected to the valve box. When the valve body 10 is closed as shown in the figure, it functions as the side seat portion 9b, and the valve box side seat portion 9b is caused by the elasticity of the valve box side seat portion 9b so that the valve body side seat portion 10a at the periphery of the valve body 10 is shown. And the valve box side seat portion 9b by the pressing force urging of the pressing force adjustment plate 11 made of a disc spring interposed between the valve box 8 and the base side vertical piece of the valve seat body 9 made of metal plate. Is more strongly pressed against the valve body side seat portion 10a to maintain the sealing performance (Patent Document 2).

Japanese Utility Model Publication No. 52-117631 Japanese Utility Model Publication No. 5-8140

  In the valve seat structure of the valve described in Patent Document 1, when the valve body 4 is in a closed state indicated by a solid line, the concave spherical valve body side seat portion 5 formed on the back surface of the valve body 4 is an elastic sealing material 7. Since it is configured to maintain the sealing performance by being in close contact with the valve box side seat portion 3, the fluid pressure (for example, gas pressure) P that urges the valve body 4 in the valve box 1 in the upward direction. In the case where an eccentric inner surface seal valve is applied to the piping system on which the valve acts, the concave spherical spherical valve body side seat portion 5 is urged by the gas pressure P toward the valve box side seat portion 3 made of the elastic seal material 7. Thus, the adhesion between the concave spherical valve body side seat portion 5 and the valve case side seat portion 3 made of the elastic seal material 7 can be increased, and the sealing performance when the valve is closed can be improved.

  However, when an eccentric inner surface seal valve is applied to a piping system to which the gas pressure P does not act, the sealing performance when the valve is closed is determined when the valve body 4 has turned to the valve closing position indicated by the solid line. Since only the contact force between the valve body side seat portion 5 and the valve box side seat portion 3 is entrusted, when the valve body 4 is in the closed state, the weight of the valve body 4 and the rotation of attaching the valve body 4 are attached. When the valve body 4 descends corresponding to the bearing clearance due to the influence of the bearing clearance generated between the shaft 4A and the bearing (not shown), the adhesion between the valve body side seat portion 5 and the valve case side seat portion 3 is increased. And lowering the sealing performance at the time of closing the valve, and the powder is caught between the valve body side seat portion 5 and the valve case side seat portion 3 to wear and damage the valve case side seat portion 3, There is a problem of further reducing the sealing performance.

  On the other hand, in the valve seat structure of the valve disclosed in Patent Document 2, when the valve body 10 is closed, the valve box side seat portion 9b is made elastic by the valve box side seat portion 9b so that the valve body side seat at the periphery of the valve body 10 is used. In addition to being brought into pressure contact with the portion 10a, the valve box side seat portion 9b can be more strongly brought into pressure contact with the valve body side seat portion 10a by the pressing force urging of the pressing force adjusting plate 11 made of a disc spring to maintain the sealing performance. . For this reason, the fluid pressure P1 acts on the valve body 10, and the direction of the fluid pressure P1 due to the influence of the bearing gap generated between the rotary shaft (not shown) on which the valve body 10 is mounted with the valve body 4 and the bearing. Even when the valve body 10 is moved, the semicircular portion of the illustrated valve body 10 absorbs the movement of the valve body 10 by the elasticity of the valve box side seat portion 9b, and the valve box side seat portion 9b is moved to the peripheral portion of the valve body 10. The sealing performance can be ensured by pressing the valve body side seat portion 10a. However, in the semicircular portion of the valve body 10 (not shown), the valve body side seat portion 10a is excessively pressed against the valve box side seat portion 9b due to the distortion of the valve body 10 itself and the influence of the bearing gap. Then, the valve box side seat portion 9b is plastically deformed, the pressure contact force between the valve box side seat portion 9b and the valve body side seat portion 10a is lowered, and the contradictory state occurs such that the sealing performance at the time of closing the valve is lowered.

  In addition, when the fluid pressure P acts on the valve body 10 when the valve body 10 is closed, the valve body 10 shown in the figure has a semicircular portion due to the distortion of the valve body 10 itself and the influence of the bearing gap. The body 10 moves in the direction of the fluid pressure P, and the valve body side seat portion 10a is excessively pressed against the valve box side seat portion 9b, so that the valve box side seat portion 9b is plastically deformed, and the valve box side seat portion The pressure contact force between the valve body side seat portion 10a and the valve body side seat portion 10a is reduced to reduce the sealing performance when the valve is closed. In the semicircular portion of the valve body 10 (not shown), the valve body 10 is affected by the bearing clearance. Even if it moves in the direction of fluid pressure P, the movement of the valve body 10 is absorbed by the elasticity of the valve box side seat portion 9b, and the valve box side seat portion 9b is moved to the valve body side seat portion 10a at the periphery of the valve body 10. By pressing, there is a conflicting situation such as ensuring sealing performance. .

  Furthermore, if the sealing performance at the time of closing the valve is lowered due to plastic deformation of the valve box side seat portion 9b, the fluid pressure P or P1 acts on the valve body 10 when the valve body 10 is closed, and is affected by the bearing gap. Even if the valve body 10 moves in the direction of the fluid pressure P or P1, the valve box side seat portion 9b that is plastically deformed absorbs the movement of the valve body 10 in the direction of the fluid pressure P or P1 to the valve box side. There is a problem in that the seat portion 9b cannot be expected to be brought into pressure contact with the valve body side seat portion 10a at the peripheral portion of the valve body 10 and the sealing performance at the time of closing the valve is lowered.

  The present invention solves such a problem, and an object of the present invention is to ensure a high sealing performance by an urging force due to the elasticity of a valve seat in which plastic deformation is suppressed. The valve seat can be urged by the sealing fluid pressure when the valve is closed to ensure high sealing performance, and it is suitable for a valve such as a rotary valve with an internal seal structure or a ball valve with an external seal structure. To provide a structure.

  In order to achieve the object, the valve seat structure according to the first aspect of the present invention includes a valve body seat portion provided on a valve body at a distal end portion of a bellows type valve seat having a base portion attached to the valve box side. A valve box side seat portion is provided that contacts and separates, and is configured to be urged by the elasticity of the bellows type valve seat so that the valve box side seat portion is in close contact with the valve body seat portion when the valve body is closed. And the sealing fluid pressure at the time of closing the valve body urges the bellows type valve seat so that the valve box side seat portion is in close contact with the valve body seat portion, Mounting from the axis of the bellows type valve seat to the outer end of the base in order to increase the action of the pressure applied to the bellows type valve seat as an external pressure at the time of body closing to extend the bellows type valve seat in the axial direction The valve body is in close contact with the valve body seat portion in a closed state from the radius R and the axis. Between the sealing radius R1 to Kiben box side sheet portion, and is characterized in that it has a relationship of R <R1.

According to the above configuration, when the valve body is closed, the valve box side seat portion is brought into close contact with the valve body seat portion by the first action by the elastic urging force of the bellows type valve seat to ensure high sealing performance. can do. Further, when the pressure of the fluid sealed by closing the valve body is applied to the bellows type valve seat, a second action for urging the bellows type valve seat to extend in the axial direction occurs. Due to this second action, the bellows type valve seat is extended in the axial direction, and the close contact force of the valve box side seat portion with respect to the valve body seat portion can be enhanced, thereby ensuring high sealing performance. That is, in the valve seat structure of the valve according to the first aspect of the invention, high sealing performance can be ensured by a combined action in which the second action is added to the first action.
Further, even if the bellows type valve seat is excessively pressed by the valve body when the valve body is closed, the compression deformation due to the excessive pressing is caused by a plurality of peaks and valleys constituting the bellows type valve seat. Since it can disperse | distribute and absorb in the compression deformation of a site | part, the plastic deformation of a bellows type valve seat can be suppressed, and a high sealing performance can be ensured in the state which maintained elasticity.
In particular, in the valve seat structure according to the first aspect of the present invention, the sealing fluid pressure when the valve body is closed is loaded as an external pressure on the bellows type valve seat, and the mounting radius R and the seal radius R1 of the bellows type valve seat are set. Therefore, the pressure receiving surface Δr corresponding to R1-R is formed on the surface of the peak portion of the bellows type valve seat, and the pressure receiving surface Δr The action of extending the bellows type valve seat in the axial direction is increased by the stop fluid pressure. Therefore, the adhesive force of the valve box side seat portion with respect to the valve body seat portion is further enhanced, and a strong sealing property can be secured.

  Further, the valve seat structure of the valve according to the invention of claim 2 is such that the base portion is in contact with and separated from the valve body seat portion provided on the valve body at the tip of the bellows type valve seat attached to the valve box side. A seat portion is provided, and is configured to be urged by the elasticity of the bellows type valve seat so that the valve box side seat portion is in close contact with the valve body seat portion when the valve body is closed. The sealing fluid pressure at the time of closing the body is configured to urge the bellows type valve seat so that the valve box side seat portion is in close contact with the valve body seat portion. In order to increase the action of the pressure applied to the bellows type valve seat in the axial direction, the mounting radius R from the axis of the bellows type valve seat to the outer end of the base, and the axis To the valve box side seat part that is in close contact with the valve body seat part when the valve body is closed. Between the sealing radius R1 of, it is characterized in that it has a relationship of R1 <R.

According to the above configuration, when the valve body is closed, the valve box side seat portion is brought into close contact with the valve body seat portion by the first action by the elastic urging force of the bellows type valve seat to ensure high sealing performance. can do. Further, when the pressure of the fluid sealed by closing the valve body is applied to the bellows type valve seat, a second action for urging the bellows type valve seat to extend in the axial direction occurs. Due to this second action, the bellows type valve seat is extended in the axial direction, and the close contact force of the valve box side seat portion with respect to the valve body seat portion can be enhanced, thereby ensuring high sealing performance. That is, in the valve seat structure of the valve according to the second aspect of the invention, high sealing performance can be ensured by the combined action in which the second action is added to the first action.
Further, even if the bellows type valve seat is excessively pressed by the valve body when the valve body is closed, the compression deformation due to the excessive pressing is caused by a plurality of peaks and valleys constituting the bellows type valve seat. Since it can disperse | distribute and absorb in the compression deformation of a site | part, the plastic deformation of a bellows type valve seat can be suppressed, and a high sealing performance can be ensured in the state which maintained elasticity.
In particular, in the valve seat structure of the valve according to the second aspect of the invention, the sealing fluid pressure when the valve body is closed is loaded as an internal pressure on the bellows type valve seat, and the mounting radius R and the seal radius R1 of the bellows type valve seat are set. Therefore, the pressure receiving surface Δr corresponding to R-R1 is formed on the surface of the peak portion of the bellows type valve seat, and the pressure receiving surface Δr The action of extending the bellows type valve seat in the axial direction is increased by the stop fluid pressure. Therefore, the adhesive force of the valve box side seat portion with respect to the valve body seat portion is further enhanced, and a strong sealing property can be secured.

  A valve seat structure for a valve according to a third aspect of the present invention is the valve seat structure for a valve according to the first or second aspect of the present invention, wherein the valve body is constituted by a rotary valve body. In addition, a configuration is provided in which a concave spherical valve body seat portion that is in contact with and separated from the valve box side seat portion of the bellows type valve seat is provided. According to this, the valve seat structure of the valve according to the first or second aspect of the invention can be applied to a rotary valve having an inner surface seal structure.

  A valve seat structure for a valve according to a fourth aspect of the present invention opens and closes the bellows type valve seat in a valve box on the base side of the bellows type valve seat in the valve seat structure of the valve according to the third aspect of the invention. A configuration in which a butterfly valve is incorporated is added. According to this, the valve seat structure according to the first to third aspects of the invention can be applied to, for example, a composite valve mounted on a pipeline system that transfers powder by carrier gas.

  According to the present invention, by restraining the plastic deformation of the bellows type valve seat, the urging force due to the elasticity of the bellows type valve seat is maintained for a long period of time, and the valve box side seat portion is brought into close contact with the valve body seat portion. High sealing performance can be ensured. In addition, the valve box side seat can be brought into close contact with the valve seat by the sealing fluid pressure when the valve is closed, thereby ensuring high sealing performance.

  FIG. 1 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a rotary valve having an internal seal structure. In this figure, the rotary valve V having an inner seal structure has an inlet 20 a at the upper end of the valve box 20 and a concentric outlet 20 b at the lower end of the valve box 20. A valve box sleeve 21 is accommodated in the valve box 20 concentrically with the inlet 20a and the outlet 20b. The base end 21a is fixed to the valve box 20, and the distal end 21b opens toward the outlet 20b. ing.

  Inside the valve box sleeve 21, a butterfly valve 22 for opening and closing the in-sleeve flow path 21A is arranged, and the tip 21b of the valve box sleeve 21 is a rotary valve formed with a concave spherical valve body seat portion 23 on the back surface. The body 24 is opened and closed by rotating 90 degrees. A butterfly valve valve rod 25 that pivotally supports the butterfly valve 22 passes through one side surface of the valve box 20 in an airtight and rotatable manner and is connected to a butterfly valve opening / closing means (not shown). The rotary valve body valve rod 26 that is pivotally supported is airtight and rotatable through the other side surface of the valve box 20, and is connected to a rotary valve opening / closing means (not shown).

  A bellows type valve seat 27 is attached to the distal end portion 21 b of the valve box sleeve 21. The bellows type valve seat 27 is made of a metal having excellent heat resistance and wear resistance, such as a cobalt base alloy, a nickel base alloy, and a chromium base alloy. As shown in FIG. 2, a plurality of portions of a valley portion 27 a that is reduced in the radial direction and a peak portion 27 b that is expanded in the radial direction are continuous in the axial direction, and the base portion 28 is a bolt. 29 is attached concentrically to the distal end portion 21 b of the valve box sleeve 21 via 29, and at the distal end portion, a valve box side seat portion 30 that contacts and separates from a concave spherical valve body seat portion 23 formed on the back surface of the rotary valve body 24. Is provided. As described above, the bellows type valve seat 27 is made of a metal having excellent heat resistance and wear resistance, such as a cobalt base alloy, a nickel base alloy, and a chromium base alloy, so that it can be used at a high temperature. In addition, the applicable range of the bellows type valve seat 27 can be expanded, and the deterioration of the sealing performance accompanying wear of the valve box side seat portion 30 can be suppressed, and the durability of the valve seat structure of the valve can be improved.

  On the other hand, the valve box side seat portion 30 of the bellows type valve seat 27 is provided with a built-up portion 31 made of a cemented carbide such as stellite having excellent heat resistance and wear resistance. Part 30 is configured. Therefore, it is possible to further suppress the deterioration of the valve seat structure due to thermal deterioration of the valve box side seat portion 30 and to further improve the durability of the valve seat structure. It is possible to further improve the durability of the valve seat structure of the valve by further reliably suppressing the deterioration of the performance.

1, 2 and 3, the axis C of the bellows type valve seat 27 (this axis C is the same as the axes of the valve box 20 and the valve box sleeve 21 in the present embodiment). ) To the outer end of the base portion 28, and a built-up portion 31 (valve box side seat) that is in close contact with the concave spherical valve body seat portion 23 when the rotary valve body 24 is closed from the axis C. The relationship with the seal radius R1 up to the portion 30) is set to R ≦ R1, preferably R <R1. That is, R = R1 is set in the reference example of FIG. 2, and R <R1 is set in the embodiment of FIG.

  In the above-described configuration, the rotary valve V having an inner seal structure is used by connecting the inlet 20a of the valve box 20 to a powder supply system and connecting the outlet 20b to a carrier system through which high-pressure carrier gas flows. . It is also possible to intervene in the middle of the conveyance system that flows with the powder.

  In the opening operation of the rotary valve V, first, the rotary valve body 24 is rotated 90 degrees from the position indicated by the solid line in FIG. 1 to the position indicated by the two-dot chain line, and then the butterfly valve 22 is indicated by the solid line. To 90 ° to the position indicated by the two-dot chain line. In this state, the powder falls by its own weight from the inlet 20a of the valve box 20 through the valve box sleeve 21 and flows into the conveying system through the outlet 20b.

  To close the rotary valve V, first, the butterfly valve 22 is reversely rotated 90 degrees from the position indicated by the two-dot chain line to the position indicated by the solid line to block the powder flow, and the powder flow around the bellows type valve seat 27 is reduced. In a state where no body is present, the rotary valve body 24 is reversely rotated 90 degrees from the position indicated by the two-dot chain line to the position indicated by the solid line to close the valve. This prevents powder from getting caught between the built-up portion 31 (valve box side seat portion 30) of the bellows type valve seat 27 and the concave spherical valve body seat portion 23 of the rotary valve body 24. Thus, the sealing performance can be ensured.

In the reference example shown in FIG. 2, when the rotary valve body 24 is closed, the built-up portion 31 (the valve box side seat portion 30) is formed into the concave spherical shape of the rotary valve body 24 by the elastic biasing force of the bellows type valve seat 27. It is possible to ensure high sealing performance by closely contacting the valve body seat portion 23. Further, when the rotary valve body 24 is closed, the pressure P of the carrier gas flowing through the carrier system is loaded on the bellows type valve seat 27 as an external pressure. Then, the relationship between the mounting radius R and the seal radius R1 is set to R = R1, and the pressure P is applied as an external pressure to the trough portion 27a that has a recess amount larger than the recess amount of the trough portion 27c. Since the action of energizing the bellows type valve seat 27 so as to extend in the axial direction occurs, [the indentation amount is the indentation radial dimension “indentation depth” and the indentation circumferential length “indentation”. This means that the bellows type valve seat 27 is extended in the axial direction (bends in the axial direction) by this action, and the valve box side seat portion with respect to the valve body seat portion 23. High sealing performance can be ensured by increasing the adhesion of 30. That is, in the reference example of FIG. 2, the bellows type valve seat 27 is formed by the elastic biasing force of the bellows type valve seat 27 with the built-up portion 31 (valve box side seat portion 30) of the concave spherical valve body seat portion 23. In addition to the action of bringing the bellows type valve seat 27 into the axial direction by the external pressure P, the valve section seat of the concave spherical surface of the rotary valve body 24 is formed by extending the built-up portion 31 (valve box side seat portion 30). A high sealing performance can be ensured by a combined action in which the action of closely contacting the portion 23 is added.

On the other hand, when the relationship between the attachment radius R of the bellows type valve seat 27 and the seal radius R1 is set to R <R1 as in the embodiment shown in FIG. 3, the pressure receiving surface Δr corresponding to R1-R is the peak portion 27b. Corresponding to the pressure receiving surface Δr formed on the surface, the action of extending the bellows type valve seat 27 in the axial direction by the external pressure P becomes larger than the reference example of FIG. Therefore, the bellows type valve seat 27 is extended in the axial direction more strongly than the reference example of FIG. 2 (bends in the axial direction) by securing its own elastic urging force and pressure receiving surface Δr. A stronger sealing property than that of the reference example shown in FIG. 2 can also be secured by further increasing the adhesion of the valve box side seat portion 30 to the valve body seat portion 23.

  Further, when the rotary valve body 24 shown in FIGS. 1, 2 and 3 is closed, the pressure P of the carrier gas acts on the surface of the rotary valve body 24, and the bellows type valve seat 27 excessively forms the valve box sleeve. Even if pressed to the side 21, the compression deformation of the bellows type valve seat 27 due to this excessive pressing results in compression deformation of a plurality of portions of the peak portion 27b and the valley portions 27a, 27c constituting the bellows type valve seat 27. Since it can be dispersed and absorbed, plastic deformation of the bellows type valve seat 27 is suppressed and elasticity can be maintained. For this reason, it is possible to secure the high sealing performance by bringing the built-up portion 31 (valve box side seat portion 30) into close contact with the concave spherical valve body side seat portion 23 of the rotary valve body 24 by the maintained elastic biasing force. it can.

  Further, if the pressure P of the carrier gas does not act on the surface of the rotary valve body 24, the weight of the rotary valve body 24 and the rotary valve body 24 are attached when the rotary valve body 24 is closed. Due to the influence of the bearing gap generated between the rotary valve element valve stem 26 and the bearing (not shown), the rotary valve element 24 is lowered corresponding to the bearing gap. However, for the reasons described above, the lowering of the rotary valve body 24 corresponding to the bearing gap is compensated by the elastic biasing force maintained by suppressing the plastic deformation of the bellows type valve seat 27, and the built-up portion 31 (valve box side seat portion 30) can be brought into close contact with the concave spherical valve body seat portion 23 of the rotary valve body 24 to ensure high sealing performance.

In the embodiment shown in FIG. 3, the structure is described in which the pressure P of the carrier gas is loaded on the bellows type valve seat 27 as the external pressure when the rotary valve body 24 is closed, but the gas pressure P1 is the internal pressure. When the bellows type valve seat 27 is loaded, the relationship between the mounting radius R of the bellows type valve seat 27 and the seal radius R1 is set to R> R1 , so that the bellows type valve seat 27 is axially moved by the internal pressure P1. Thus, the build-up portion 31 (valve box side seat portion 30) can be brought into close contact with the concave spherical valve body seat portion 23 of the rotary valve body 24.

The valve seat structure of the valve according to the present invention can be applied to a ball valve V1 having an outer seal structure as shown in FIGS. In FIG. 4, a valve box 20 provided with an inlet 20a and an outlet 20b is provided with a valve rod 32 having an axis C1 perpendicular to the axis C of the valve box 20, and rotates around the axis C1 together with the valve rod 32. The spherical valve body 33 is accommodated, and bellows type valve seats 27 are arranged at two positions on both sides of the spherical valve body 33 in the direction of the axis C, and the respective built-up portions 31 (valve box side seats). The portion 30) is closely attached to the convex spherical valve body sheet portion 23 constituting the surface of the spherical valve body 33. As shown in FIG. 5, the relationship between the mounting radius R of the bellows type valve seat 27 and the seal radius R1 is set to R <R1, and a pressure receiving surface Δr corresponding to R1-R is provided .

  As shown in FIG. 5, when the fluid pressure P acts on the inflow port 20a with the valve body 33 closed, the fluid pressure P is loaded as an internal pressure on the inner surface of the bellows type valve seat 27 on the upstream side. As a result, the upstream bellows type valve seat 27 is biased so as to be shortened in the axial direction, so that the upstream side bellows type valve seat 27 is slightly shortened in the axial direction (axial direction). And the adhesion force of the built-up portion 31 (valve box side sheet portion 30) to the convex spherical valve body sheet portion 23 is reduced. For this reason, as shown by arrows P1 and P2, the fluid pressure P passes between the convex spherical valve body seat portion 23 and the built-up portion 31 (valve box side seat portion 30), and then the bellows on the downstream side. The surface of the mold valve seat 27 is loaded. As a result, for the reasons described above, the downstream bellows type valve seat 27 is extended in the axial direction (bends in the axial direction), and the adhesion of the valve box side seat portion 30 to the valve body seat portion 23 is enhanced. Therefore, high sealing performance can be secured by the bellows type valve seat 27 on the downstream side.

  On the other hand, even if the spherical valve element 33 is slightly displaced in the direction of the outlet 20b corresponding to the bearing gap due to the influence of the bearing gap generated between the valve stem 32 and the bearing (not shown), this displacement Is compensated by the elasticity of the upstream bellows type valve seat 27, and the build-up portion 31 (valve box side seat portion 30) is brought into close contact with the spherical valve body seat portion 23 on the surface of the spherical valve body 33, High sealing performance can be secured. Thus, even if the downstream bellows type valve seat 27 is excessively pressed toward the outlet 20b by the slight displacement of the spherical valve body 33 in the direction of the outlet 20b, Since the compressive deformation of the bellows type valve seat 27 on the downstream side can be dispersed and absorbed in the compressive deformation of a plurality of portions of the peak portion 27b and the valley portions 27a and 27c constituting the bellows type valve seat 27, the downstream The plastic deformation of the side bellows type valve seat 27 is suppressed, and the elasticity can be maintained. Therefore, it is possible to ensure high sealing performance by bringing the build-up portion 31 (valve box side seat portion 30) into close contact with the spherical valve body seat portion 23 on the surface of the spherical valve body 33 by this elastic biasing force.

  When the spherical pressure body 33 is closed and the fluid pressure P1 is applied to the spherical valve body 33 from the outlet 20b, the upstream bellows type valve seat 27 and the downstream bellows The mold valve seat 27 acts oppositely to the case where the aforementioned fluid pressure P is applied to the spherical valve body 33 from the inflow port 20a. Therefore, the fluid pressure P1 is applied to the spherical valve body 33 from the outflow port 20b. The explanation of the operation when loaded is omitted.

It is a longitudinal cross-sectional view which shows embodiment which applied this invention to the rotary valve of the inner surface seal structure. It is a longitudinal cross-sectional view which expands and shows a part of reference example of a bellows type valve seat. It is a longitudinal sectional view showing an enlarged part of the implementation form of bellows-type valve seat. It is a longitudinal cross-sectional view which shows embodiment which applied this invention to the ball valve of an outer surface seal structure. It is explanatory drawing of the sealing effect | action at the time of applying to a ball valve. It is a longitudinal cross-sectional view of a 1st prior art example. It is a longitudinal cross-sectional view of a 2nd prior art example.

20 Valve box 22 Butterfly valve 23 Concave spherical valve body seat (valve seat of composite valve)
Rotating valve body (composite valve body)
27 Bellows type valve seat 28 Base part of bellows type valve seat 30 Valve box side seat part (seat part of bellows type valve seat)
33 Spherical valve body (Ball valve body)
34 Spherical valve seat (ball valve seat)

Claims (4)

A valve box side seat portion that comes in contact with and separates from the valve body seat portion provided on the valve body is provided at the tip of the bellows type valve seat whose base is attached to the valve box side, and is energized by the elasticity of the bellow type valve seat. The valve box side seat portion is in close contact with the valve body seat portion when the valve body is closed, and the sealing fluid pressure when the valve body is closed attaches the bellows type valve seat. The valve box side seat portion is configured to closely contact the valve body seat portion, and the pressure applied to the bellows type valve seat as the external pressure when the valve body is closed causes the bellow type valve seat to In order to increase the extending action in the axial direction, the mounting radius R from the axial line of the bellows type valve seat to the outer end of the base part, and the valve body seat part in close contact with the valve body from the axis line in the closed state. R <R1 in relation to the seal radius R1 to the valve box side seat portion A valve seat structure of the valve, characterized in that that. A valve box side seat portion that comes in contact with and separates from the valve body seat portion provided on the valve body is provided at the tip of the bellows type valve seat whose base is attached to the valve box side, and is energized by the elasticity of the bellow type valve seat. The valve box side seat portion is in close contact with the valve body seat portion when the valve body is closed, and the sealing fluid pressure when the valve body is closed attaches the bellows type valve seat. The valve box side seat portion is configured to closely contact the valve body seat portion, and the pressure applied to the bellows type valve seat as the internal pressure when the valve body is closed causes the bellow type valve seat to In order to increase the extending action in the axial direction, the mounting radius R from the axial line of the bellows type valve seat to the outer end of the base part, and the valve body seat part in close contact with the valve body from the axis line in the closed state. R1 <R between the seal radius R1 and the valve box side seat portion. A valve seat structure of the valve, characterized in Rukoto. In the valve seat structure of the valve according to claim 1 or 2 ,
The valve body is constituted by a rotary valve body, and the rotary valve body is provided with a concave spherical valve body seat portion that contacts and separates from a valve box side seat portion of the bellows type valve seat. Valve seat structure to perform. In the valve seat structure of the valve according to claim 3 ,
A valve seat structure for a valve, wherein a butterfly valve for opening and closing the bellows type valve seat is incorporated in a valve box on a base side of the bellows type valve seat.

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