Rotary Valve Seal

The present invention is directed to valves. More specifically, the present invention is directed to a fluid seal for a rotary valve.

An object of the present invention is to provide an improved fluid seal for a rotary valve.

In accomplishing this and other objects, there has been provided, in accordance with the present invention a seal for a rotary valve to provide a fluid seal with a selectively positionable valve closure member in a fluid passage within the body of the rotary valve. A valve seal ring has a first side face contacting a peripheral edge of the closure member in a valve closed state of the closure member and a second side face having a tapered wall recess. An annular valve seat located adjacent to the seal ring has an outwardly extending coaxial annular rib in the form of a cantilever beam having a tapered surface at a free end thereof. A contact between the tapered wall and the tapered surface provides a selectively positionable fluid-tight seal.

A better understanding of the present invention may be had when the following detailed description is read in connection with the accompanying drawings, in which:

FIG. 1 is a cross-sectional illustration of an example of a valve seal embodying the present invention and showing the valve during a fluid sealing operation and

FIG. 2 is a cross-sectional illustration of the valve seal shown in FIG. 1 at the conclusion of the valve sealing operation.

Referring to the figures in more detail, there is shown an example of a fluid seal embodying the present invention for providing a fluid seal within a rotary valve in combination with a selectively positionable valve seal member 2 located within a valve body 4. The selectively positionable member 2 may be the closure element of a so-called butterfly valve, such devices being well-known in the art, e.g., see U.S. Pat. No. 2,893,682.

The valve body 4 is provided with an annular recess 6 having a side wall 8 overlying a portion of a side face of an outwardly extending rib 9 on an annular valve seal ring 10. A coaxial opening 12 extending through the seal ring 10 provides a fluid flow path. A peripheral edge of the closure member 2 is arranged to contact a first face 11 of the seal ring 10 to close the coaxial opening through the seal ring 10 when the closure member 2 is in a valve closed position. An annular recess 14 is located in a second side face 13 of the seal 10 opposite to the first face 11 contacted by the valve closure member 2. A tapered surface 16 is provided on a side wall of the recess 14 extending substantially from the face of the seal 10 to the bottom of the recess 14.

An annular valve seat 18 is located within the valve body adjacent to the seal 10 and spaced therefrom. An annular ridge in the form of an outwardly projecting cantilever beam is located on an inner face of the valve seat 18 adjacent to the seal 10. The free end of the cantilever beam 20 is terminated in a tapered end face 22 arranged to mate with the tapered wall surface 16 of the recess 14. The valve seat 18 is also provided with a coaxial opening 24 to provide a fluid passage therethrough. The valve seat 18 is captured within the valve body 4 by a threaded retaining ring 26 having a coaxial opening 28 as a fluid passage therethrough. Thus, the valve seat ring 18 provides a fluid seal between the valve seat ring 18 and the valve body 4 by the pressure exerted by the retaining ring 26 which urges the valve seat ring 18 against a mating step leading to the recess 6. Additionally, the tapered side face 22 of the cantilever beam 20 is arranged to contact the tapered side wall 16 of the recess 14 to provide a fluid-tight seal therebetween.

As shown in FIG. 1, the seal 10 is located with the rib 9 abutting the side wall 8 of the recess 6 during a valve open condition. In this position of the seal 10, the tapered face 22 is located near the outside end of the tapered side wall 16 adjacent to the second side face 13 of the seal 10. In this condition, the fluid controlled by the valve would flow through the channel provided by the coaxial openings 12, 24 and 28.

In FIG. 2, there is shown a valve closed condition of the valve wherein the valve closure member 2 has a peripheral edge in contact with a corner of the first face 11 of the seal 10. In this state of the valve, the seal 10 is displaced during the closure operation by the closure member 2 toward the valve seat 18 whereby the annular rib 9 is spaced from the side wall 8 of the recess 6. Since the seal ring 10 is loosely captured, i.e., "free floating", it is able to position itself accurately on the closure member 2 in a coaxial relationship, i.e., self-centering. The aforesaid displacement of the seal ring 10 by the closure member 2 produces a movement of the tapered face 22 of the cantilever beam 20 on the tapered side wall 16 of the recess 14. However, during this motion the fluid-tight engagement of the tapered face 22 with the tapered side wall 16 is maintained. The end position of the tapered face 22 on the tapered wall is dependent on the ability of the seal ring 10 to accommodate the mechanical eccentricities leading to the valve closed state of the closure member 2. Thus, in the valve closed condition, a fluid tight seal is provided within the valve between the closure member 2 and the seat ring 18. The seal ring 10 and the valve seat 18 may advantageously be made of a rigid and resilient material to maintain the aforesaid fluid-tight seal in the presence of a high-temperature environment, e.g., stainless steel.

Accordingly, it may be seen that there has been provided, in accordance with the present invention, an improved valve seal for a rotary valve.