JPH0229326Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a butterfly valve, and in particular, the invention relates to a butterfly valve, in particular a butterfly valve that is equipped with a sealing part mechanism made of a rigid material such as a metal sheet, and has a seat clamp and a seat ring separately. Regarding the seat ring.

(Prior Art) In a conventional butterfly valve, as shown in FIG.
is enclosed in a thin plate, has a substantially J-shaped cross section, has a seat ring 2 which is given elasticity by the coil spring 1 at the seating part with the valve body 5, and the seat ring 2 is connected to the main body (valve body ) 3 and the seat presser 4, and the valve body (valve plate) 5 is placed in pressure contact with the circumferential surface of the valve body (valve plate) 5, thereby achieving a fluid sealing effect.

In addition, when the valve body 5 is in pressure contact with the seat (valve seat), the coil spring inside the seat ring 2 is arranged so that the pressing force against the valve body 5 by the coil spring 1 of the seat ring 2 is not impaired on the seating surface. An annular backup spring 6 is inscribed on the back surface of the part.

At the contact point between the coil spring 1 and the back-up spring 6, a force N in a direction perpendicular to the plane of the back-up spring 6 acts on the valve body 5 side, as shown in FIG. At the contact point, a component force F=N cos θ due to this force acts, and the fluid is sealed by this component force.

Further, a semi-circular convex portion 2a is provided on the flat surface portion of the seat ring 2 extending outward in the radial direction, and the apex of the convex portion 2a and the flat surface portion of the sheet presser 4 on the main body 3 side are provided. A recess 4a is provided in the sheet presser metal fitting 4 so as to be in contact with the sheet presser metal fitting 4. Therefore, even if the valve body 5 is bent or moved in the seat pressing direction due to the fluid pressure P, the seat ring 2
The bending moment (f×
1), the flat part of the seat ring 2 is also slightly displaced in the direction of the seat presser 4, so that the abutment position between the valve body 5 and the seat ring 2 does not deviate greatly. The force N or F did not become excessively large. In addition, in the figure, 7 indicates a valve stem, and 8 indicates a gasket packing.

(Problems to be solved by the invention) The conventional butterfly valve described above has the following problems.

(i) Since the cover plate of the seat ring is made of extremely thin metal, the convex portion 2a of the flat plate portion of the seat ring is caused by the pressing force of the valve body 5 toward the seat clamp when the valve is closed. It deforms plastically and cannot maintain the spring effect due to the bending moment described above for a long period of time.

(ii) In high-temperature specifications, thermal distortion of the valve body 5 and seat ring 2 due to high heat does not escape to the outside due to the back-up spring 6 on the back of the seat ring, but occurs only inward, and as a result, the torque when opening and closing the valve is reduced. It is very likely that it will become large and cause damage to the seating area.

(Means for Solving the Problems) In order to solve the above-mentioned problems of the prior art, the present invention provides a main body on the plane part of the radiating part of the seat ring, which is made of an annular elastic body with an approximately J-shaped cross section. A convex portion that protrudes toward the side, that is, the seating portion side, and the top of the convex portion is brought into contact with the wall surface of the main body. The valve body is characterized in that the side plane portion is deviated so as to protrude toward the main body, and furthermore, the seat ring mounting groove of the main body is provided with an escape area for the seat ring as the valve body shifts.

(Function) The present invention is configured as described above, so that
The convex part of the seat ring is provided in the opposite direction to the conventional one, so when fluid pressure acts on the valve body from the valve stem direction of the valve body, in other words, fluid pressure acts on the seat retainer. In this case, the convex portion is not adversely affected by the pressing force caused by the fluid pressure, and the seat ring is brought into close contact with the valve body edge by the reaction force from the wall of the seat clamp. and closes off the fluid. That is, in this case,
As the valve body moves, the seat ring is pushed up in the outer circumferential direction, and at the same time, the frictional force between the valve body and the seat ring creates a reaction force on the wall of the seat ring and the seat clamp, as shown in Figure 2. The reaction force generated by this reaction force, which is perpendicular to the seating surface of the valve body, becomes a sealing force and seals the fluid.

Furthermore, when fluid pressure toward the valve stem of the valve body is acting on the valve body, the valve body moves in a direction to separate from the seat ring. However, in this invention,
Fluid also enters the gap between the flat part of the seat ring and the seat clamp and exerts pressure, so the seat ring is bent so that it follows the movement of the valve body, using the contact point of the convex part with the main body as a fulcrum. work. For this reason,
Even in this case, the sealing force is maintained and the fluid is sealed.

On the other hand, at high temperatures, a clearance is provided between the outer periphery of the seat ring and the inner periphery of the main body groove without the conventional back-up spring. You can run away. In addition, in this case, the seat ring plane part is configured such that the inside of the convex part deviates from the outside towards the main body side, that is, the seating side, so the bending moment due to the deviation (displacement) causes the seat ring to Easier to move due to clearance side.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of a butterfly valve using a seat ring showing an embodiment of the present invention.
Among the numerals shown in this drawing, the same numerals as those shown in FIG. 5 indicate the same or similar parts.

In the figure, the seat ring 12 is composed of an annular elastic body with a substantially J-shaped cross section, and a coil spring is installed inside the seat ring 12 so as to provide non-directional elasticity at the seating part (contact part) with the valve body 5. A convex portion 12a that protrudes toward the main body 3 side, that is, the seating portion side, is provided on the radial plane portion. The apex of the convex portion 12a is located at the concave wall surface 3a of the main body 3.
The inner and outer plane parts of the convex part 12a are not the same plane, but have a deviation amount ε, so that the inner side, that is, the central axis side plane part 12b protrudes toward the main body 3 side, and the outer plane part 12c is held between the main body 3 and the sheet presser metal fitting 14 via the gasket packing 8. Further, the seat ring mounting groove 3b of the main body 3 is provided with a space (clearance) for the seat ring 12 to escape when the valve body 5 shifts.

On the other hand, the seat retainer 14 is placed in an eccentric position so that the inner side protrudes toward the valve body 3 side, with the border near the convex portion 12a of the seat ring so as to contact the flat portions 12b, 12c of the seat ring. A stepped portion is formed with ε.

According to this embodiment, during operation, fluid pressure is applied to the valve body 5.
When applied from the valve stem direction (from the left side of the diagram),
As shown in FIG. 2, the fluid pressure P moves the valve body 5 from the two-dot chain line position to the solid line position, forcing the seat ring 12 in the outer circumferential direction without any adverse effect on the convex portion 12a. At the same time, due to the frictional force between the valve body 5 and the seat ring 12, the flat part 12 of the seat ring 12 is pushed up without being deformed.
A reaction force F acts between b and the wall surface of the seat clamp 14, and a resistance force f'(f'=Fsinθ) perpendicular to the valve body seating surface generated by the reaction force F becomes a sealing force to tightly seal the seating surface. , and fluid sealing is achieved.

Further, when the fluid pressure is acting in the direction of the valve stem (to the left in the figure), the valve body 5 shifts in the direction of separating from the seat ring 12, and with this shift, the seat ring flat portion 12b and Fluid also enters the gap between the seat ring 12 and the seat clamp 14, and a pressure p acts as shown in FIG.
Bending M= with the contact point between a and the main body 3 as the fulcrum
Apl/2 works to follow the movement of the valve body 5 (to the left in the figure). Therefore, even in this case, the sealing force is maintained and the fluid is occluded.

On the other hand, at high temperatures, a clearance (escape area) is formed at the outer periphery of the seat ring 12, so that distortion due to thermal expansion between the valve body 5 and the seat ring 12 can easily escape, and the valve body The seat ring also easily shifts as it moves, so no strain is placed on the seating surface. In this case, the inner plane part 12b of the seat ring is deviated so as to extend ε toward the seating side (main body side), so as shown in FIG. ′ tends to generate a clockwise moment M′=f′ε′ that moves the seat ring 12 toward the clearance side as shown by the dotted line. Therefore, in the above case, the seat ring 12 tends to move toward the clearance side.

In addition, in the above embodiment, the structure in which the coil spring 1 is included in the seat ring was explained, but
Of course, it is not limited to this.

(Effects of the invention) As explained above, the invention provides the following effects.

(i) Since the convex portion provided on the flat surface of the seat ring protrudes toward the main body, even when the valve body is pressed toward the seat ring by fluid pressure from the valve stem direction when the valve is closed, the convex portion The spring effect caused by the bending moment can be maintained for a long period of time without causing plastic deformation. Further, even when fluid pressure is applied in the opposite direction, that is, in the direction in which the valve body moves away from the seat ring, the seat ring works to follow the movement of the valve body, and the sealing force is maintained.

(ii) Since a seat ring escape area is provided in the seat ring mounting groove of the main body, deformation of the seat ring can be minimized, distortion caused by thermal expansion at high temperatures can also be released, and the sealing force is much smaller than that of conventional products. Since the valve is set, the seat will not be damaged and the torque required to open and close the valve can be reduced.

(iii) Since the seat ring flat part is deviated so that the inside of the convex part protrudes toward the main body, the seat ring can easily move to the relief part of the main body, and the torque required when opening and closing the valve can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the essential parts of a butterfly valve using a seat ring showing an embodiment of the present invention, Fig. 2 is an explanatory view of the same operation, Figs. 3 and 4 are explanatory views of the operating state, FIG. 5 is a sectional view of a main part of a conventional butterfly valve, and FIGS. 6 and 7 are explanatory views of the same operation. 3... Main body, 5... Valve body, 12... Seat ring, 12a... Convex portion, 12b, 12c... Plane portion, 14... Seat presser.

Claims (1)

[Claims for Utility Model Registration] 1. In a butterfly valve having a seat clamp and a seat ring separately, the seat ring is composed of an annular elastic body with a substantially J-shaped cross section and is disposed between the main body and the seat clamp. , a convex portion protruding toward the main body is provided on the radially flat surface of the annular seat ring, the top of which is brought into contact with the main body wall surface, and the flat surfaces on both the inner and outer sides of the convex portion in the radial direction are the same. A seat ring for a butterfly valve, characterized in that the inner plane part is not flat but is offset toward the main body side, and the seat ring mounting groove of the main body is provided with an escape area for the seat ring as the valve body shifts. 2. The seat ring for a butterfly valve according to claim 1, wherein the annular seat ring includes a coil spring.