JPH0755413Y2 - Butterfly valve seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a seal structure in a butterfly valve used for opening and closing various fluid pipelines.

(Prior Art) As a conventional sealing structure for this type of valve, for example,
There is the one shown in the 60-2020 publication.

In the conventional seal structure, as shown in FIG. 4, a seat ring 11 formed of an elastic material is formed on the inner peripheral surface of a cylindrical body 13 that rotatably supports a disc (valve body) 15. A pair of valve shaft holes 14 for mounting the stem shaft 16 of the disc 15 are formed at the diametrically opposite positions of the seat ring 11 while being mounted, and the disc 15 is provided near the periphery of each valve shaft hole 14. While forming the boss contact surface 12 that constantly press-contacts the boss 15b defined at the base of the stem shaft 16, on the peripheral surface of the seat ring 11,
The recessed groove 11a into which the outer peripheral edge 15c of the disk 15 when the valve is closed is continuously formed.

Further, in the conventional seal structure, the seat ring 11
The boss contact surface 12 and the concave groove 11a into which the outer peripheral edge 15c of the disc 15 at the time of valve closing are formed in the same spherical surface, and the outer peripheral surface including the boss portion 15b of the disc 15 is also formed in the same spherical surface, The contact resistance is reduced to ensure the sealing performance when the valve is closed. In the figure, Ro indicates the spherical surface of the boss portion 15b, R indicates the spherical surface of the boss contact surface 12 having the same spherical shape as the spherical surface Ro, and the radius of the spherical surface Ro is slightly larger than that of the spherical surface R. Has become.

(Problems to be solved by the invention) However, in the conventional seal structure, as shown in FIG. 5, the boss contact surface 12 of the seat ring 11 and the outer peripheral surface of the boss 15b of the disc 15 are the same. The spherical shape means that
At first glance, it seems that the contact resistance between the two can be reduced, but in reality, the boss contact surface 12 does not matter whether the valve is open or closed, the boss 15b of the disc 15 made of a rigid material and the rigid material are the same. Since it is a place where it is strongly compressed between the bodies 13 molded in, when the disc 15 is repeatedly fully opened and closed, the boss contact surface 12 wears due to surface pressure contact with the boss 15b, and durability And the sealing surface pressure between the boss portion 15b of the disk 15 and the boss portion contact surface 12 of the seat ring 11 is remarkably reduced, causing a serious problem of fluid leakage.

(Means for Solving Problems) The present invention was developed in order to effectively solve the problems of the conventional seal structure, in which the disc is rotatably supported. A seat ring formed of an elastic material is mounted on the inner peripheral surface of the body, and a pair of valve shaft holes for mounting the stem shaft of the disk are formed at diametrically opposed positions of the seat ring, and In the seat structure of a butterfly valve in which a boss contact surface that is in constant pressure contact with the disc boss is formed in the vicinity of the valve shaft hole, the disc boss surface is formed in a spherical shape and closely contacts the boss surface. The boss contact surface of the seat ring is provided by the inner side and the outer side of the valve shaft hole, the inner side is provided with a planar shape that is pressed by the boss side of the disc, and the outer side is provided with the disc boss. When a conical surface shape that is pressed by the surface is provided, In addition, a configuration is adopted in which the boss surface strongly presses the planar shape to increase the seal surface pressure on the stem shaft side.

(Operation) Therefore, in the present invention, even if the boss contact surface of the seat ring is a portion that is strongly compressed between the disc boss and the body regardless of whether the valve is opened or closed. ,
Due to the synergistic effect of the boss portion surface of the spherical disc and the boss contact surface of the aspherical seat ring, the two are partially in linear pressure contact with each other and the sealing pressure can be increased.

Therefore, as in the conventional case, there is no fear that the sealing pressure at the contact surface between the disc boss and the seat ring boss is reduced and fluid leakage occurs.

(Embodiment) Hereinafter, the present invention will be described in detail with reference to an illustrated embodiment.
The seal structure of the butterfly valve according to the embodiment is basically developed on the premise of the conventional structure shown in FIG. 4 described above, but the features are as follows.

That is, in the conventional structure, the boss contact surface of the seat ring and the boss surface of the disc have the same spherical surface, whereas in the present embodiment, the spherical boss surface and the aspheric surface of the disc are spherical. It is characterized in that the boss contact surface of the sheet ring is formed.

More specifically, in the first embodiment, as shown in FIGS. 1A and 2A, the valve shaft hole of the seat ring 1 mounted on the inner peripheral surface of the tubular body 3 4, when forming the boss contact surface 2 near the periphery of the boss 4, the inner side of the boss contact surface 2 near the valve shaft hole 4 has a planar shape R1 and the outer side protrudes inward. R1 '.

In the figure, Ro indicates the spherical surface of the boss portion 5b, and R indicates the spherical surface of the conventional boss portion contact surface which has the same spherical shape as the spherical surface Ro.

Further, the spherical surface of the concave groove 1a which fits the outer peripheral edge of the disc 5 formed on the peripheral surface of the seat ring 1 and the spherical surface of the boss portion 5b of the outer peripheral edge 5c of the disc 5 have the same spherical surface as shown in FIG. It is in a state.

Therefore, in the first embodiment having such a structure, as shown in FIG. 2A in particular, for example, the boss contact surface 2 of the seat ring 1 is
However, regardless of whether the valve is opened or closed, even if it is strongly compressed between the boss portion 5b of the disc 5 and the body 3, the plane shape R1 of the inner portion near the valve shaft hole 4 and the conical surface of the outer portion are formed. shape
By the synergistic action of R1 ′, a sealing surface pressure is generated between the boss 5b surface of the disc 5 and the boss contact surface 2 of the seat ring 1,
Since a high sealing pressure shown by an arrow is obtained (a long area of the arrow has a large sealing surface pressure), the sealing property becomes excellent.

Further, in the second embodiment, as shown in FIGS. 1B and 2B, the boss contact surface 2 of the seat ring 1 has a plane shape R2.

Therefore, in the second embodiment having such a structure, as shown in FIG. 2B in particular, the spherical surface Ro of the boss portion 5b and the plane shape R2 of the aspherical boss portion contact surface 2 are acted upon by the action. , Disk 5
Between the boss 5b surface of the and the boss contact surface 2 of the seat ring 1,
A high seal pressure indicated by an arrow is obtained in which the surface pressure is large at the long line of the inner peripheral edge of the valve shaft hole 4.

Particularly, in the second embodiment and the first embodiment, the disk 5
Since a higher sealing pressure (F surface pressure) can be obtained on the side of the stem shaft 6 (not shown) mounted in the mounting hole 5a, the sealing performance for the stem shaft itself is also improved.

In the third embodiment, as shown in FIGS. 1C and 2C, the boss contact surface 2 of the seat ring 1 has a conical surface shape R3 continuous from the hole edge of the valve shaft hole 4, Further, in the fourth embodiment, as shown in FIG. 1D and FIG. 2D, in the boss contact surface 2 of the seat ring 1, the inner part and the outer part near the valve shaft hole 4 are different. It has a conical surface shape of R4 / R5.

Therefore, even in the third and fourth embodiments, as in the first and second embodiments described above, the conical surface shapes R4 and R5 synergize with the boss portion 5b surface of the disk 5. Since a larger surface pressure acts on the outer peripheral edge side between the boss contact surfaces 2 of the seat ring 1 and a high sealing pressure shown by an arrow is obtained, the sealing property becomes good.

Further, in each of the embodiments, the boss portion 5b surface of the spherical disc 5 and the boss portion contact surface 2 having an aspherical surface are different from the conventional ones, and are partially in linear pressure contact with the boss portion 5b surface. Needless to say, durability is improved with less wear.

In the present invention, it is sufficient if at least the boss 5b surface of the disc 5 is spherical and the boss contact surface 2 of the seat ring 1 is aspherical in any state. It is needless to say that the shape is not limited to the shape of the embodiment and can be changed to other various shapes.

(Effect of the Invention) As described above, according to the present invention, the boss surface of the disk is spherical,
Since the boss contact surface of the seat ring is formed in an aspherical shape so as to bring them into close contact with each other, for example, the boss contact surface of the seat ring does not depend on whether the valve is opened or closed. Even if it is a portion that is strongly compressed between the boss portion and the body, the high sealing pressure is always obtained by the synergistic action of the boss portion surface of the disc and the boss portion contact surface of the seat ring.

Therefore, unlike the conventional case, the sealing pressure at the contact surface between the disc boss portion and the seat ring boss portion is reduced, and there is no fear of causing fluid leakage.

Moreover, since the seal pressure (F surface pressure) as shown by the arrow in FIG. 2 (A) is generated on the side of the stem shaft attached to the disc, there is an effect that the sealing property with respect to the stem shaft is remarkably improved.

[Brief description of drawings]

FIGS. 1A and 2A are explanatory views of a main part showing a seal structure of a first embodiment of the present invention, and FIGS. 1B and 2B are second views of the present invention.
The principal part explanatory view showing the seal structure of the embodiment, FIG. 1C / second
FIG. C is an explanatory view of a main part showing a seal structure of a third embodiment of the present invention, and FIGS. 1D and 2D are main part explanatory views showing a seal structure of a fourth embodiment of the present invention, FIG. Is an explanatory view showing the relationship between the outer peripheral edge of the disk and the concave groove of the seeking ring in each example,
FIG. 4 is a plan view showing a conventional butterfly valve and its seal structure, and FIG. 5 is an explanatory view of a main part showing a relationship between a disc boss portion and a seat ring boss contact surface. 1 ... Seat ring, 2 ... Boss contact surface, 3 ... Body, 4 ... Valve shaft hole, 5 ... Disc, 5b ... Boss.

Claims (1)

[Scope of utility model registration request] 1. A seat ring formed of an elastic material is mounted on the inner peripheral surface of a body that rotatably supports the disk, and a stem shaft of the disk is mounted at a position diametrically opposed to the seat ring. A seat structure of a butterfly valve, wherein a pair of valve shaft holes for axial mounting are formed, and a boss contact surface that is in constant pressure contact with the boss of the disc is formed in the vicinity of each valve shaft hole. The surface is formed spherical, and the boss contact surface of the seat ring that is in close contact with the boss surface is provided by the inner side and the outer side of the valve shaft hole, and the inner side is pressed by the disc boss surface. A planar shape is provided, and a conical surface shape that is pressed by the boss portion surface of the disc is provided on the outer side portion thereof, and the boss portion surface strongly presses the planar shape to increase the seal surface pressure on the stem shaft side. Butterflies characterized by Seal structure of the valve.