JP3121527B2 - Butterfly valve body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve body of a butterfly valve, and more particularly to a valve body of a butterfly valve which can optimize a sealing surface pressure between the valve body and a seat ring.

[0002]

2. Description of the Related Art A center type butterfly valve in which an outer peripheral edge of a disc-shaped valve body is cut into an inner peripheral surface of a seat ring made of an elastic sealing material to obtain a sealing surface pressure is conventionally shown in FIGS. Disc-shaped valve element (1) as shown in 6
Is constituted by a spherical surface having the same diameter as the outer diameter R of the valve element (1). Such a spherical valve element has the advantage that the amount of crushing of the seat ring (2) by the valve element (1) can be made substantially uniform over the entire circumference of the valve element (1).

The contact surface pressure between the valve body (1) and the seat ring (2), which is one of the indicators of the sealing ability of the butterfly valve, that is, the seal surface pressure of the valve body (1) is determined by the seat ring.
If the crushing amount t of (2) is constant, it changes depending on the contact area between them, and if the contact area becomes large, the sealing surface pressure per unit area becomes low, and the sealing performance deteriorates. or,
In the center type butterfly valve, the contact area with the seat ring (2) of the boss portion (1b) constituting the valve-dedicated penetration portion is larger than the contact area on the outer peripheral surface (1a) of the valve body (1). (1c) is a valve stem.

Therefore, conventionally, a boss having a large contact area is used.
In (1b), the outer diameter of the valve body (1) is set so that the squeezing amount t required to obtain a sufficient sealing surface pressure is obtained. There was a problem that the sealing surface pressure was increased more than necessary and the opening / closing torque of the valve body (1) was increased, or the wear of the valve body (1) and the seat ring (2) was increased, and the durability was reduced. .

Further, since the entire width of the outer peripheral surface (1a) of the valve body (1) bites into the seat ring (2), the thickness of the valve body (1) is increased so that the strength is sufficient to cope with the biting reaction force. Therefore, there is a problem that the thickness of the valve body (1) is limited due to the necessity of securing the thickness. Further, in such a spherical valve element (1), it is extremely difficult to chamfer the edge (1d) of the outer peripheral surface (1a) of the valve element (1) by rotary cutting because the blade hits the boss (1b). It is. Therefore, when opening and closing the valve body (1), the edge of the outer peripheral surface (1a)
(1d) bites into seat ring (2) and seat ring (2)
This has been a cause of scraping off or increasing the opening / closing torque of the valve element (1).

Further, as shown in FIG. 6, even when the valve element (1) is fully opened and held, the boss (1b) bites into the seat ring (2) and is held. For this reason, if the valve opening state is continued for a long time, the seat ring (2) may be deformed due to the biting of the boss portion (1b) and a step may be generated. there were.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is possible to obtain a substantially uniform sealing surface pressure with a small bite over the entire circumference of a valve body. It is possible to suppress the scraping of the seat ring by the outer peripheral surface of the body, reduce the opening / closing torque of the valve body, and provide a butterfly valve body in which the amount of crushing of the seat ring does not suddenly change regardless of the state of the valve body. It will not be provided.

[0008]

In order to solve the above-mentioned problems, the present invention adopts a sealing method in which the outer peripheral edge of a disc-shaped valve element is cut into the inner peripheral surface of a seat ring made of an elastic sealing material. In a center type butterfly valve for obtaining a surface pressure, all the outer peripheral surfaces including a boss portion of the valve body are constituted by the same curved surface having a radius smaller than a radius of an outer diameter of the valve body.

[0009]

According to the present invention, the following effects can be obtained by employing the means for solving the above problems.

[0010] 1. Since the sealing surface pressure becomes uniform over the entire circumference of the valve body, the sealing performance becomes uniform over the entire circumference of the valve body, and stable sealing performance can be obtained by securing a necessary minimum crushing amount.

2. The squeezing area is smaller, so the squeezing amount can be made smaller than before, and the valve body can be opened and closed with a smaller torque, so the valve body driving device can be downsized and the load on the seat ring can be reduced. The durability of the seat ring is improved.

3. Since the edge of the outer peripheral surface of the valve body is eliminated, biting into the seat ring is performed smoothly, and deterioration of the seat ring is suppressed, and the driving torque of the valve body is reduced.

4. Even when fully opened, the crush of the seat ring does not change suddenly, so it is difficult for the seat ring to be deformed even under adverse conditions such as leaving it open for a long time, eliminating the cause of deterioration in sealing performance I can do it.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. In the figure, (1
Reference numeral 0) denotes a seat ring attached to the inner peripheral surface of a valve body (not shown), which is formed of an elastic sealing material such as rubber in a ring shape. Valve body disposed on the inner circumference of the seat ring (10)
(11) is formed in the shape of a disk, and bosses (13) for attaching valve stems (12) to both ends (upper and lower ends in the figure) of the opposing position.
Is provided.

[0015] Then, all of the valve body (11) including the boss portion (13) is provided.
Smaller radius r than the radius R of the outer peripheral surface of the (14), the valve body (11)
By configuring in the same curved surface, the outer peripheral surface (14) by the curved surface, i.e. the outer periphery of the seat ring of the valve body (11) (1
The center type butterfly valve which obtains the seal surface pressure by making it bite into the inner peripheral surface of 0) is constituted.

Therefore, the seat ring (10) by the valve body (11)
The crushing area is substantially the same even when the width (thickness) of the valve body (11) is increased, and the crushing area by the valve body (11) is substantially the same including the boss portion (13). And the same seal surface pressure is obtained.

Further, even when the thickness of the valve element (11) is large, the radius of the curved surface constituting the outer peripheral surface (14) of the valve element (11) is small, so that the area of biting into the seat ring (10) is small. Even when the bite amount e of the valve element (11) is reduced, a sealing surface pressure similar to that of the related art can be obtained, and the driving torque of the valve element (11) decreases. Further, the valve element (11) cuts into the seat ring (10) on the outer peripheral surface (14) constituted by a curved surface, and the radius r of the curved surface is equal to the radius R of the outer diameter of the valve element (11).
A smaller seat ring as shown in FIGS. 1 and 2
The amount of bite into (10) gradually increases from the mouth as it goes from the edge to the center.

Accordingly, even when the seat ring (10) is fully opened, the amount of crushing of the seat ring (10) by the boss portion (13) does not change suddenly.
Even when the butterfly valve is left open for a long time in the fully opened state, the seat ring (10) is hardly deformed, and the cause of the deterioration of the sealing performance is eliminated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a seal structure according to an embodiment of a valve body of a butterfly valve according to the present invention.

FIG. 2 is a sectional view showing a seal structure around a valve rod.

FIG. 3 is a perspective view showing a conventional spherical valve element.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a cross-sectional view showing a sealing structure using the spherical valve element shown in FIG. 3;

FIG. 6 is a cross-sectional view showing a seal structure around a valve rod by the spherical valve element shown in FIG. 3;

[Explanation of symbols]

 (10) Seat ring (11) Valve (12) Valve stem (13) Boss (14) Outer surface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-26018 (JP, A) JP-A-7-167309 (JP, A) Fully open 1981-56 (JP, U) Really open 2464 (JP, U) Fully open sho 55-8263 (JP, U) Fully open sho 64-3160 (JP, U) Fully open 1983, 58-138866 (JP, U) Fully open, 1983 53-7219 (JP, U) Hikaru 4-19961 (JP, U) JP-B-55-44262 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16K 1/16-1/54

Claims (1)

(57) [Claims] 1. A center type butterfly valve in which an outer peripheral edge of a disc-shaped valve body is cut into an inner peripheral surface of a seat ring made of an elastic sealing material to obtain a sealing surface pressure, wherein a boss portion of the valve body is provided. Characterized in that all the outer peripheral surfaces including the same are formed of the same curved surface having a radius smaller than the radius of the outer diameter of the valve body.