Butterfly valve seat

Claim 2

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valVe housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: providing annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc.

Claim 3

The improvement of claim 1 wherein said annular flexible seat means comprise an annular outer element adapted to be constrained between adjacent surfaces of the elements constituting said valve, an inner element disposed within said annulus of said outer element and containing an inclined seating surface adapted to seat against said convergent circumferential sealing surface on said disc, and a flexible linking element joining said inner element to said outer element and permitting said inner element to deflect in a downstream direction in response to the application thereto of fluid pressure emanating from either direction along said fluid flow channel.

Claim 4

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valve housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: providing annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc, and wherein said annular flexible seat means comprise an annular outer element adapted to be constrained between adjacent surfaces of the elements constituting said valve, an inner element disposed within said annulus of said outer element and containing an inclined seating surface adapted to seat against said convergent circumferential sealing surface on said disc, and a flexible linking element joining said inner element to said outer element and permitting said inner element to deflect in a downstream direction in response to the application thereto of fluid pressure emanating from either direction along said fluid flow channel, and wherein the deflection of said inner element occurs by virtue of flexure in said linking element about one of a pair of pivot points on said adjacent surfaces, said pivot point on that side of said annular seat means facing said direction of convergence being located closer to the center of said annular seating means than said pivot point on the other side thereof, whereby internal fluid pressure of a given magnitude tends to deflect said inner element more when applied from the said direction of convergence than when applied from the opposite direction.

Claim 5

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valve housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: providing annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc, and wherein said annular flexible seat means comprise an annular outer element adapted to be constrained between adjacent surfaces of the elements constituting said valve, an inner element disposed within said annulus of said outer element and containing an inclined seating surface adapted to seat against said convergent circumferential sealing surface on said disc, and a flexible linking element joining said inner element to said outer element and permitting said inner element to deflect in a downstream direction in response to the application thereto of fluid pressure emanating from either direction along said fluid flow channel, and wherein the deflection of said inner element occurs by virtue of flexure in said linking element about one of a pair of pivot points on said adjacent surfaces, said pivot point on that side of said annular seat means facing said direction of convergence being located closer to the center of said annular seating means than said pivot point on the other side thereof, whereby internal fluid pressure of a given magnitude tends to deflect said inner element more when applied from the said direction of convergence than when applied from the opposite direction.

Claim 6

The improvement of claim 2 wherein a rigid Element adjacent to said inner element intercepts said inner element as it tends to deflect in response to internal fluid pressure of a magnitude not greater than the design pressure of said valve and emanating from the direction opposite to said direction of convergence.

Claim 7

The improvement of claim 1 wherein a rigid element is located adjacent said flexible annular seat means and on the same side thereof as the said direction of convergence, said rigid element being positioned sufficiently close to said flexible annular seat means to intercept the deflection of said annular flexible seat means in response to internal fluid pressure of a magnitude not greater than the design pressure of said valve and emanating from the direction opposite to said direction of convergence.

Claim 8

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valve housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: providing annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc wherein a rigid element is located adjacent said flexible annular seat means and on the same side thereof as the said direction of convergence, said rigid element being positioned sufficiently close to said flexible annular seat means to intercept the deflection of said annular flexible seat means in response to internal fluid pressure of a magnitude not greater than the design pressure of said valve and emanating from the direction opposite to said direction of convergence, and wherein said rigid element is located in such proximity to said flexible annular seat means as to permit less deflection thereof in said direction of convergence than said flexible annular seat means is free to deflect in the opposite direction.

Claim 9

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valve housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: providing annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc wherein a rigid element is located adjacent said flexible annular seat means and on the same side thereof as the said direction of convergence, said rigid element being positioned sufficiently close to said flexible annular seat means to intercept the deflection of said annular flexible seat means in response to internal fluid pressure of a magnitude not greater than the design pressure of said valve and emanating from the direction opposite to said direction of convergence, and wherein said rigid element is located in such proximity to said flexible annular seat means as to permit less deflection thereof in said direction of convergence than said flexible annular seat means is free to deflect in the opposite direction.

Claim 10

The improvement of claim 1 wherein the projection upon a plane perpendicular to the said flow axis of that portion of the surface of said flexible seat means which is free to flex and is exposed to internal fluid pressure when said pressure is emanating from the direction of convergence contains a greater area than the projection upon the same plane of that portion of the surface of said flexible seat means which is free to flex and is thus exposed when said pressure is emanating from the opposite direction.

Claim 11

The improvement of claim 1 wherein said seat means and said circumferential sealing surface are in interference fit in relation to each other in said closed position in the absence of the action of internal fluid pressure on said valve.

Claim 12

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valve housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: proViding annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc wherein said annular flexible seat means comprise an annular outer element adapted to be constrained between adjacent surfaces of the elements constituting said valve, an inner element disposed within said annulus of said outer element and containing an inclined seating surface adapted to seat against said convergent circumferential sealing surface on said disc, and a flexible linking element joining said inner element to said outer element and permitting said inner element to deflect in a downstream direction in response to the application thereto of fluid pressure emanating from either direction along said fluid flow channel, and wherein a rigid element adjacent to said inner element intercepts said inner element as it tends to deflect in response to internal fluid pressure of a magnitude not greater than the design pressure of said valve and emanating from the direction opposite to said direction of convergence, and wherein said rigid element is located in such proximity to said inner element as to permit less deflection thereof in said direction of convergence than said inner element is free to deflect in the opposite direction.

Claim 13

In a butterfly valve comprising annular flexible seat means circumscribing the fluid flow channel defined by the interior surfaces of a valve housing, a disc mounted in said valve housing for rotation about an axis substantially perpendicular to the flow axis of said fluid flow channel, and a circumferential sealing surface on said disc cooperating with said seat means to block the flow of fluid through said fluid flow channel when said disc is rotated into the closed position, said sealing surface being a segment of a substantially converging surface, the improvement comprising: proViding annular flexible seat means which tend to deflect more than the said disc in the downstream direction when internal fluid pressure of a given magnitude is applied from the direction of convergence of said sealing surface and which also tend to deflect less than said disc when said fluid pressure is applied from the opposite direction, whereby internal fluid pressure, regardless of the direction from which it is applied, increases the sealing effectiveness of said seat means on said disc wherein said annular flexible seat means comprise an annular outer element adapted to be constrained between adjacent surfaces of the elements constituting said valve, an inner element disposed within said annulus of said outer element and containing an inclined seating surface adapted to seat against said convergent circumferential sealing surface on said disc, and a flexible linking element joining said inner element to said outer element and permitting said inner element to deflect in a downstream direction in response to the application thereto of fluid pressure emanating from either direction along said fluid flow channel, and wherein a rigid element adjacent to said inner element intercepts said inner element as it tends to deflect in response to internal fluid pressure of a magnitude not greater than the design pressure of said valve and emanating from the direction opposite to said direction of convergence, and wherein said rigid element is located in such proximity to said inner element as to permit less deflection thereof in said direction of convergence than said inner element is free to deflect in the opposite direction.