JPS628694Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a butterfly valve having a metal seat.

A chimney-shaped valve having a metal seat is mainly used for opening and closing pipelines through which high-temperature gas flows, and chimney-shaped valves having the structure described below are conventionally known.

That is, as shown in FIG. 1 (see Japanese Patent Application Laid-Open No. 54-67156), the metal seat 1 is composed of a double ring, and has a gasket part that functions as a gasket to prevent the pressure inside the valve from escaping to the outside of the valve. 1B and
Seat part 1 that acts as a dynamic seal between valve plate 3
Prepare with A. The seat portion 1A is surrounded on three sides by three members made of rigid materials: the valve body 2, the auxiliary ring 5, and the retainer 4. When the valve plate 3 is closed, the seat portion 1A is closed as shown in FIG. It is surrounded on all sides by rigid material.

Metal seat chimney valves with this structure are
It has the drawback of heavy rotational torque and easy fluid leakage.

The reason why such a defect occurs is that when the valve plate 3 is closed, the valve plate 3 bites into the seat portion 1A and deforms the seat portion 1A, but the seat portion 1A is made of rigid material on four sides as described above. Because it is surrounded, it cannot be deformed freely, and a strong repulsive force is exerted on the valve plate 3, causing a large frictional force, resulting in an increase in the rotational torque of the valve plate 3.

By the way, if the threading allowance for the seat portion 1A of the valve plate 3 is increased, the rotational torque increases to such an extent that it is impossible to open and close the valve. It was impossible to hold. For this reason, the machining tolerances of the valve components cannot be fully absorbed, making them prone to leakage. On the other hand, if the coil spring 1D is weakened to weaken the repulsive force, there will be insufficient force to push back the deformation of the outer skin of the metal sheet.
It was also impossible to weaken the coil spring because the outer skin would be permanently deformed and no longer function as a seal.

In addition, if a large pressure such as surge pressure is applied to the valve plate 3, even temporarily, the valve plate 3 will move downstream, excessively deforming the main seat ring portion and causing permanent distortion. Another drawback was that if a pressure below the rated value was applied again after the pressure had passed, it would leak.

In addition to the above, post-shaped valves having the following structure are also known. In other words, Fig. 2 (Japanese Unexamined Patent Publication No. 57-124166
In addition to the main sheet 1, another metal O-ring having the same structure as the seat portion 1A of the main sheet is inserted as a secondary metal sheet 7, as shown in the above publication. This type of chisel-shaped valve is expensive and has the drawback of leaking against counter pressure applied from the opposite direction to the shaft side of the valve body.

The reason for this defect is that when back pressure is applied to the valve body, the valve plate is pushed and tries to move away from the main seat seat portion 1A, but the back pressure is sealed by the secondary metal seat 7, and the main seat Since the main seat did not cover the flange portion 1C, the main seat could not follow the movement of the valve plate, and the spacing between the valve plate and the seat portion 1A was insufficient, resulting in leakage. Furthermore, since a total of two metal sheets, which are originally gaskets for nuclear equipment, are used in addition to the main sheet 1, the cost is high.

The technical problem of this invention is to lower the repulsion spring constant of the seat portion of the metal sheet against the valve plate at low cost and in a manner that does not prevent back pressure from being applied to the flange portion of the metal sheet, and to To enable a seat part to move in a direction to avoid an excessive load when an excessive load is applied to the seat part.

The technical means of the present invention for solving the above technical problems is an eccentric metal sheet chimney-shaped valve, and
The metal seat has a flange portion for being tightened and held onto the valve body, and a seat portion for contacting and sealing the valve plate, and the seat portion is curled into a hollow O-ring shape, In a chiral valve with a built-in coil spring in the valve body, an annular elastic body that elastically supports one surface of the seat part is placed in parallel with the seat part on the opposite side of the shaft of the valve body, and the elastic body of the seat part The deformation is allowed by the elastic deformation of the elastic body, and the elastic body is provided with a flow path through which the reverse pressure applied from the opposite direction to the shaft side of the valve body passes.

The technical means of this invention works as follows. In other words, when the valve is closed, the seat part is pushed and deformed by the valve plate, but if the seat part is surrounded by a rigid body at this time, the seat part cannot deform freely and is subject to a strong repulsive force. This acts as a reaction force on the valve plate, but if at least one side of the seat is supported by an elastic member, the deformation of the seat is transmitted to the elastic member supporting it and deforms it as well. Therefore, since the seat portion can be deformed more freely than when the entire seat portion is surrounded by rigid members, the repulsive force of the seat portion against the valve plate is reduced. That is, the repulsion spring constant decreases, and the seat portion contacts the valve plate as a soft spring.

As a result, the frictional force between the valve plate and the seat portion is reduced, and the rotational torque for opening and closing the valve is reduced.

On the other hand, when back pressure is applied to the valve, the back pressure passes through the elastic body and is applied to the flange section and seat section of the main seat, and the flange section 10C is pushed by the back pressure and bends, so the seat section moves in the downstream direction. The valve plate follows the valve plate, which moves in the same way, and prevents a decrease in the clearance between the valve plate and the seat, making it difficult for leaks to occur even in the case of reverse pressure.

Also, when the valve is closed, when excessive pressure is applied to the valve stem side (positive pressure side) of the valve plate due to surge pressure, etc., and the valve plate moves and tries to crush the seat part, the elastic body Since the seat part is deformed and released away from the valve plate, there is no risk of permanent deformation occurring in the seat part and damage to the seat part.

The elastic body that supports the metal sheet part may have a structure that has a flow path that allows reverse pressure to pass through.
Coil springs, plate springs, plate rubber, etc. that can be mass-produced can be used.

The unique effects of this invention are as follows. That is, in order to solve the above technical problem, in addition to supporting the seat part with an elastic body as in the present invention,
As shown in the figure, it is possible to provide a lip 8 on the retainer ring and use it to support the seat, but this method requires changing the dimensions of the lip to match the spring constant each time the material of the retainer ring is changed. However, in this design, the shape of the retainer ring can be kept constant regardless of the material, and the shape of the retainer ring can be fixed regardless of the material. The advantage is that if the body is damaged, only the elastic body needs to be replaced. Furthermore, a metal sheet chimney-shaped valve with light rotation torque, good sealing performance, resistance to leakage against reverse pressure, and resistance to damage of the seal portion by surge pressure can be obtained.

Examples of this invention will be described below with reference to the drawings. Referring to FIG. 3, numeral 10 is a main sheet made of a metal sheet, and has a seat portion 10A, a gasket portion 10B, and a flange portion 10C. 11 is the valve body, 12 is the valve plate, 1
3 is a retainer ring. The above structure is the same as that shown in FIG.

14 is an elastic body made of a leaf spring; 15
is a hole provided in the leaf spring 14, and constitutes a flow path through which a reverse pressure applied from the opposite direction to the shaft side of the valve body passes. When the valve plate 12 closes, the seat portion 10A is pushed and deformed, but this deformation is transmitted to the leaf spring 14 and also deforms it. As a result, the seat portion 10A
can be easily deformed, reducing the repulsion spring constant.

When reverse pressure is applied, the valve plate 12 is pushed and slightly moved upstream. On the other hand, the counter pressure passes through the hole 15, and as shown by arrow P, the flange portion 10C of the metal sheet 10
And it hangs over the seat part 10A, and the flange part 10C
is bent upstream to make the seat portion 10A follow the valve plate 12. The leaf spring 14 can be mass-produced at low cost by press molding.

The spring constant of the leaf spring 14 should preferably be equal to the spring constant of the seat portion, and even if it is changed, it should be within a range of ±50%. Even if the leaf spring 14 is too soft or too hard, the desired effect cannot be expected.

FIG. 4 shows another embodiment of this invention, in which a coil spring 16 is used in place of the leaf spring 14, and a ring 17 prevents the coil spring 16 from falling off in the radial direction. Other points are 3rd
This is equivalent to the embodiment shown in the figure. In this embodiment, the counter pressure passes through the coil spring 16 in the direction of arrow P using the coil gap as a flow path, and is applied to the flange portion 10C and the seat portion 10A.

FIG. 5 shows still another embodiment, in which a rubber ring 1 is used instead of the plate spring 14 and the coil spring 16.
8 is used, and the rubber ring 18 is provided with a groove 19 that serves as a flow path for counter pressure. Other points are the same as the embodiments shown in FIGS. 3 and 4.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a part of the structure of a known metal seat butterfly valve, and FIG. 2 is a partial sectional view of the metal seat portion of another known metal seat butterfly valve. 3 is a partial sectional view of a metal sheet part showing an embodiment of this invention, FIG. 4 is a partial sectional view of a metal sheet part showing another embodiment of this invention, and FIG. 5 is a further embodiment of this invention. FIG. 6 is a partial cross-sectional view of the metal sheet portion showing another embodiment, and is a reference view for explaining the effects of this invention, and is a partial cross-sectional view of the metal sheet portion. 10...metal sheet, 10A...seat part,
10B... Gasket part, 10C... Flange part, 11... Valve body, 12... Valve plate, 13... Retainer ring, 14... Leaf spring, 15... Hole, 1
6...Coil spring, 17...Ring, 18...Rubber ring, 19...Groove.

Claims (1)

[Claims for Utility Model Registration] (1) An eccentric metal seat chimney-shaped valve, the metal seat comprising a flange portion for being tightened and held onto the valve body, and a seat portion for contacting and sealing the valve plate. The seat part is curled into a hollow O-ring shape, and in a chime-shaped valve having a built-in coil spring in the hollow part of the seat part, one surface of the seat part is placed on the opposite side from the shaft of the valve body. An annular elastic body that elastically supports the valve body is arranged in parallel with the seat part, allowing elastic deformation of the seat part by the elastic deformation of the elastic body. A chisel-shaped valve having a metal seat, characterized in that it is provided with a flow path through which such reverse pressure passes. (2) Claim 1 of the Utility Model Registration Claim characterized in that the elastic body consists of a plate spring having a U-shaped cross section, and the flow path through which the counter pressure passes is a hole penetrating the plate spring. Later, it became a Yo-gata valve. (3) The post-shaped valve according to claim 1, wherein the elastic body is a coil spring, and the gap between the coils is used as a flow path through which reverse pressure passes. (4) The post-shaped valve according to claim 1, wherein the elastic body is made of a rubber ring, and the passage through which the counter pressure passes is a groove formed in the elastic body.