초록 ▼

This disclosure relates to the construction of butterfly valves of the type used for controlling fluid flow and, more particularly, to a seal for use in sealing the periphery of the closure member of such valves. Further, the seal disclosed herein is loaded by the pressure of the fluid being handled

This disclosure relates to the construction of butterfly valves of the type used for controlling fluid flow and, more particularly, to a seal for use in sealing the periphery of the closure member of such valves. Further, the seal disclosed herein is loaded by the pressure of the fluid being handled, to enhance the tightness of the seal.

대표청구항 ▼

1. In a butterfly valve of the type having a valve body with a cylindrical fluid passage therethrough, and a substantially disc-shaped closure member mounted in the fluid passage for rotation between an open position and a closed position about an axis transverse to the fluid passage, and wherein th

1. In a butterfly valve of the type having a valve body with a cylindrical fluid passage therethrough, and a substantially disc-shaped closure member mounted in the fluid passage for rotation between an open position and a closed position about an axis transverse to the fluid passage, and wherein the closure member further has a peripheral sealing surface, the improvement comprising a seal for tightly sealing the peripheral sealing surface of the closure member, such seal comprising: in the valve body, an annular groove circumscribing the fluid passage and disposed substantially in alignment with the peripheral sealing surface of the closure member when the closure member is in the closed position; the annular groove, in cross section, being generally T-shaped, with a substantially rectangular cavity forming the cap of the T and a narrower sleeve portion extending between that cavity and the surface of the fluid passage and forming the shank of the T; a resilient seat ring member disposed in and projecting from the annular groove into the fluid passage; the seat ring member, in cross section, having at least a first leg and a second leg such legs being joined together at a first end of each and diverging therefrom, and a stem portion projecting from the first and second legs at their joined ends; the second ends of the first and second legs of the seat ring member sealingly bearing against the top wall of the cap of the T defining said rectangular cavity; the stem portion of the seat ring member disposed in and projecting through the sleeve portion of the groove into the fluid passage; the stem portion of the seat ring member being smaller in cross-sectional width than the sleeve part of the groove, to permit fluid from the upstream side of the passage to enter the rectangular cavity and apply lateral pressure against a corresponding one of said first and second legs of the seat ring member; and said one of said first and second legs of the seat ring member being movable laterally toward the other of such legs responsive to fluid pressure created within the rectangular cavity thereby elastically deforming the seat ring member and urging the stem portion of the seat ring member against the peripheral sealing surface of the disc, the second ends of the first and second seat ring legs remaining in bearing relation against the top wall of the cap of the T defining said rectangular cavity, whereby fluid pressure enhances the contact pressure and, thus, the sealing action, between the seat ring member and the closure member as well as between the seat ring member and the groove. 2. The butterfly valve of claim 1 wherein the seat ring member further includes third and fourth legs, depending from the second ends of the first and second legs, respectively; the third and fourth legs being adapted to sealingly bear against opposite second and third walls, respectively, of the rectangular cavity joining said top wall. 3. The butterfly valve of claim 2 wherein the first, second, third, and fourth legs of the seat member provide a substantially W-shaped cross-section, with the first and second legs forming the two inner legs of the W and the third and fourth legs forming the two outer legs of the W, said third and fourth legs extending generally in the direction of said stem portion of said seat ring member. 4. The butterfly valve of any of claims 1-3 wherein the sleeve portion of the groove extends between a fourth wall of the cavity and the fluid passage, and the second ends of the first and second legs of the seat ring member project outwardly from the vicinity of such sleeve portion and to a greater extent than the sleeve portion of the groove, to retain the seat ring member in the groove. 5. The butterfly valve of claim 4 wherein the peripheral sealing surface of the valve closure member is a section of a sphere. 6. The butterfly valve of claim 5 wherein the rotational axis of the closure member is offset from a diametrical position on the closure member as well as from the center plane of the valve, whereby the rotation of the closure member involves a camming action. 7. The butterfly valve of claim 6 wherein the stem portion of the seat ring member has a surface adapted to engage the peripheral sealing surface of the closure member and such surface of the seat ring member is oriented substantially parallel to the orientation of the peripheral sealing surface of the closure member when the closure member is in the closed position. 8. The butterfly valve of any of claims 1-3 wherein the seat ring member is formed of a material having a low coefficient of friction, to facilitate the lateral motion of said one of said first and second legs of the seat ring member adapted to move laterally. 9. The butterfly valve of claim 8 wherein each leg of the seat ring member which is adapted to move laterally makes an angle of between approximately 55 and 85 degrees with said top wall of the cap of the T defining said rectangular cavity when the valve is in the open position. 10. The butterfly valve of any of claims 1-3 wherein a portion of the seat ring member comprises an elastic hinge area. 11. The butterfly valve of claim 10 wherein the seat ring member further includes a cut out slot portion adjacent said hinge area, whereby pressurized fluid is admissible to said slot to facilitate movement in the hinge area.