JPS6060377A - Valve - Google Patents

Abstract

PURPOSE:To permit the seal through metal contact between a housing and a seat retainer even if the sealing performance of a combustible seat ring is eliminated by a fire, etc. CONSTITUTION:An annular groove 11 whose inside wall surface is formed into an inclined surface 10 so that the width is reduced towards the bottom part is formed onto the outer peripheral surface of a seat retainer 4 between a valve seat 6 and a seat ring 8. A seal ring 13 having incombustibility whose free edge is cut to provide a stepped surface 12 extending in the longitudinal direction is fitted into the annular groove 11, and said ring 13 is heated from the back-surface side, and the front surface 14 is brought into face contact, and the upper surface 15 is brought into face contact with the inner wall surface of a housing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a large-diameter valve used in pipelines, etc., and more particularly to a fire-safe valve, that is, a valve that maintains its sealing function even in the event of a fire.

FIG. 1 shows a sectional view of a main part of a conventional large-diameter ball valve, in which a ball 2 as a valve body is housed in a housing 1 so as to be rotatable about a stem (not shown).
The fluid passage 3 in the housing is opened and closed. Generally, in such a large-diameter valve, an annular seat retainer 4 is fitted into the housing so as to surround the fluid passage, and an annular valve seat is disposed between an outer ring 5 fixed to the housing and an outer ring 5 fixed to the annular seat retainer 4. 6 is attached facing the valve body. The seat retainer is urged from the back side toward the valve body by compression springs 7 at regular intervals in the circumferential direction,
Thus, the annular valve seat is brought into contact with the surface of the valve body, creating a seal between the seat retainer and the valve body. Further, a seal ring 8 is installed in a groove on the outer peripheral surface of the seat retainer in sliding contact with the inner wall surface of the housing to seal between the housing and the seat retainer. In particular, fluid 1
When fluid pressure is applied to the ffi passage, it is proportional to the product of the area of the annular part whose width is the difference between the sealing point diameter of the valve seat and the outer diameter of the seat retainer, and the differential pressure between the fluid pressure and the pressure inside the cavity 9. Since the so-called self-tightening force acts from the back side of the seat retainer, the valve seat can seal the valve element more reliably.

However, the above-mentioned valve seats and seal rings are generally made of an elastic material such as rubber or synthetic resin in order to improve sealing performance by improving adhesion to the sliding surface of the valve body and housing, respectively. Therefore, since these are flammable, they will be deformed or burned down in the event of a fire, and the sealing function will be lost.

That is, as is easily understood, if the valve seat or seal ring is deformed or burnt out, the fluid in the fluid passage will flow not only between the valve body and the seat retainer, but also between the arrow a. As shown, it leaks into the cavity through the space between the inner wall surface of the housing and the outer circumferential surface of the seat retainer, and between the inner wall surface of the housing and the outer circumferential surface of the outer ring.

If the valve seat has already been deformed or burned out, the front surface of the seat retainer may be brought into direct contact with the valve body to maintain a seal between the seat retainer and the valve body through so-called metal contact. Although valves are known, it is difficult to form a metal contact with a sealing property between the seat retainer and the housing. There are no known valves that seal.

Therefore, the technical problem of the present invention is to provide a seal between the housing and the seat retainer through metal contact even if the flammable seat ring is deformed or destroyed by fire or the like and loses its sealing function. The objective is to provide a valve that can.

Figures 2 to 4 show the technical configuration for solving the above problems.
This will be explained based on the diagram. In addition, in these drawings, the first
Elements that are the same as in the figures have been given the same reference numerals.

a housing 1; a movable valve body 2 that opens and closes a fluid passage 3 within the housing; an annular seat retainer 4 fitted into the housing so as to face the valve body and surround the fluid passage; In a valve comprising an annular flammable valve seat 6 attached to the seat retainer facing the valve body, and a combustible seal ring 8 provided on the outer peripheral surface of the seat retainer in sliding contact with the inner wall surface of the housing. An annular groove 11 is provided on the outer circumferential surface of the seat retainer between the valve seat and the seal ring, the inner wall surface of which is formed into an inclined surface 10 such that the width thereof decreases toward the bottom, and the annular groove 11 has a longitudinal groove at the free end. A non-combustible seal ring 1 cut out to have a stepped surface 12 extending in the direction
3 is fitted into the annular groove, and this non-combustible seal ring is biased from its back side to bring the front surface 14 into surface contact with the slope, the top surface 15 into surface contact with the inner wall surface of the housing, and to bring the stepped surfaces together. The valve was constructed by making surface contact with the

Therefore, according to the valve of the present invention, while the valve seat and seal ring have a normal sealing function, the valve seat and the seal ring are in contact with the valve body and the housing sliding surface, respectively, as described above. to seal between the fluid passageway and the housing cavity. When the seal ring is deformed or burnt out and loses its sealing function, the front surface of the non-flammable seal ring comes into surface contact with the slope of the annular groove due to the force applied from its back surface, creating surface pressure. Due to the surface pressure, the upper surface comes into surface contact with the inner wall surface of the housing to generate surface pressure, and the stepped surfaces at the ends also come into surface contact with each other to generate surface pressure, thus creating a non-combustible relationship between the inner wall surface of the housing and the seat retainer. A metal contact seal is formed through the seal ring.

Embodiments of the valve according to the present invention will be described below based on the drawings.

FIG. 2 is a sectional view of a main part showing an embodiment of the valve according to the present invention, in which an annular seat retainer 4 is fitted in a housing 1 surrounding a fluid iJl path 3, and an outer ring fixed to this An annular combustible valve seat 6 is mounted between the valve body 5 and the valve body 2 so as to face the valve body 2 . The seat retainer is biased from the back side toward the valve body by compression springs 7 installed in blind holes provided at regular intervals in the circumferential direction on the inner wall of the housing, so that the annular valve seat is pressed against the surface of the valve body. The seat retainer and the valve body are brought into contact with each other to form a seal. In addition, a flammable seal ring 8 is also placed on the outer peripheral surface where the seat retainer slides against the inner wall surface of the housing.
is installed in the groove and seals between the housing and the seat retainer.

A non-flammable seal ring 13 is placed on the outer circumferential surface of the IJ retainer.
An annular groove 11 for mounting is provided. As shown in FIG. 3, this annular groove has an irregular cross section, and is formed so that its inner wall surface has a slope 10 so that its width becomes smaller toward the bottom of the groove. The noncombustible seal ring has a free end as shown in FIG. 4, and has a stepped surface 12 cut out at the free end and extending in the longitudinal direction of the seal ring, and when fitted into the annular groove. a front surface 14 that can make surface contact with the slope of the annular groove;
As shown in FIG. 3, when the seal ring is fitted into the annular groove while being urged by a compression spring 16 from the back surface, the front surface is in contact with the annular groove. The upper surface is in surface contact with the inner wall surface of the housing, and the step surfaces are also in surface contact with each other.

The non-combustible seal ring can be easily manufactured from, for example, a steel bar made of ordinary steel or impermeable steel, and an appropriate number of the compression springs 16 are arranged along the circumference of the seal ring 13. Ru. Note that a gap 17, 17 is usually left between the end faces of the seal ring.

Therefore, during normal operation, as described above, the valve seat contacts the valve body, and the combustible seal ring contacts the sliding surface of the housing, thereby sealing between the fluid 1ffi path and the housing cavity. When the combustible seal ring is deformed or burnt out and loses its sealing function, the non-flammable seal ring is removed from its back by the compression spring 16.
Since the front surface contacts the slope of the annular groove and generates surface pressure, the top surface contacts the inner wall of the housing and generates surface pressure, which causes the inner wall of the housing to contact the seat retainer. A metal contact seal is formed between them via a non-combustible seal ring, thus preventing fluid from leaking from the fluid passage into the cavity. Further, since the step surfaces at the ends of the non-combustible seal ring also come into surface contact with each other to generate surface pressure, fluid leakage as indicated by arrow C is also prevented by the surface pressure between the step surfaces. Furthermore, after the combustible valve seat is burned out, the seat retainer is urged toward the front valve body by the compression spring 7, so the front surface of the seat retainer comes into direct contact with the valve body.
Leakage of fluid from the fluid passage indicated by arrow a into the cavity is prevented.

In the above embodiments, the present invention has been explained using a ball valve as an example, but the present invention is not limited thereto, and it goes without saying that the present invention can also be applied to a gate valve. The metal contact seal described above is an emergency measure when the combustible seal loses its sealing function, and is not used permanently.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part showing a conventional valve, Fig. 2 is a sectional view of the main part showing the valve according to the present invention, and Fig. 3 is a sectional view of the main part showing an annular groove and a nonflammable seal ring fitted therein. FIG. 4 is a perspective view of the main part showing the end of the non-combustible seal ring. ■...housing, 2...valve body, 3...fluid passage, 4...seat retainer, 6 combustible valve seat,
8...Flammable seal ring, 1o...Slope, 11.
...Annular groove, 12...Step surface, 13...Nonflammable seal ring, 14...Front surface, 15...Top surface, 16...
compression spring.

Claims (1)

[Claims] (1) A housing, a movable valve body that opens and closes a fluid passage within the housing, an annular seat retainer fitted into the housing so as to face the valve body and surround the fluid passage; A valve comprising: an annular flammable valve seat attached to a seat retainer facing the valve body; and a combustible seal ring provided on an outer circumferential surface of the seat retainer in sliding contact with an inner wall surface of the housing,
An annular groove is provided on the outer circumferential surface of the seat retainer between the valve seat and the seal ring, the inner wall surface of which is sloped so that the width thereof decreases toward the bottom, and the annular groove extends in the longitudinal direction at the free end. A non-flammable seal ring cut out to have a stepped surface is fitted into the annular groove, and this non-flammable seal ring is biased from the back side so that the front surface is brought into surface contact with the slope, and the top surface is brought into surface contact with the inner wall surface of the housing. A valve characterized in that the stepped portions are in surface contact with each other and the stepped portions are in surface contact with each other.