Ball valve for high temperatures

Claim 2

A ball valve to resist high temperatures, comprising a hollow valve body limited by two flanges and containing a rotatable ball with a passageway for the fluid, means to rotate the ball, a sealing ring of hot-flowing resin between said ball and at least one of said flanges, the ball in the closed position of the valve having freedom of displacement within the valve body relative to said valve rotating means in the downstream direction, the flange which is downstream in the fluid flow direction having an annular groove including lateral groove walls, the sealing ring being partially disposed in said groove, said groove having a residual hollow volume which is at least equal to the volume of that portion of the sealing ring which is located outside the groove, in order to permit said groove to receive the whole of the material of the sealing ring which is located outside the groove, said downstream flange having opposite to the ball and in the vicinity of the groove a metallic seat to receive the ball in the event of elimination of the sealing ring material at high temperatures, the sealing ring having at its end remote from the ball a tubular extension tightly fitted over one of the lateral groove walls.

Claim 3

A valve according to claim 1, wherein the seat for receiving the ball is constituted by the line of intersection between a chamfer of the flange at the entrance of the passageway and the adjacent wall of the groove which contains the sealing ring.

Claim 4

A valve according to claim 1, wherein the seat for receiving the ball is constituted by an annular rib of the flange, said rib being separated from the groove containing the sealing ring by a hollow annular space.

Claim 5

A valve according claim 1, wherein the material of said sealing ring is constituted by a mixture of polytetrafluoroethylene and small particles of stainless steel.

Claim 6

A valve according to claim 1, said tubular extension being fitted over the lateral groove wall which is nearest the passageway, the sealing ring having at its end adjacent the ball an annular enlargement which is applied against opposite lateral walls of said groove and which projects outside of said groove to serve as a seat for the ball in normal use.

Claim 7

A valve according to claim 1, wherein the volume of said enlargement is such with respect to the volume of said groove as to wholly fill said groove at high temperatures.

Claim 8

A ball valve to resist high temperatures, comprising a hollow valve body limited by two flanges and containIng a rotatable ball with a passageway for the fluid, means to rotate the ball in the body, a sealing ring of hot-flowing resin between said ball and at least one of said flanges, the flange which is downstream in the direction of flow of the fluid having therein a recess defining an annular relief volume, the ball in the closed position of the valve having freedom of displacement within the valve body relative to said valve rotating means in the downstream direction, said body having a metallic seat to receive the ball on the downstream side in the event of elimination of the material of the sealing ring at high temperatures, said valve body containing at least at the downstream end a composite seal for the ball, said seal comprising an annular diaphragm with a metallic core joined to a ring of plastic material which serves as a seat for the ball in normal service, the diaphragm having a projecting annular element which surrounds the ring and is directed toward the ball, said element being so shaped as to form a seat for the ball in the event of elimination of the plastic material of the ring at high temperatures, the recess communicating with said passageway by means of a chamfer which constitutes in conjunction with said passageway a relieving volume for the plastic material in the event of hot flow, the external diameter of the chamfer being larger than the internal diameter of the sealing ring.

Claim 9

A ball valve to resist high temperatures, comprising a hollow valve body limited by two flanges and containIng a rotatable ball with a passageway for the fluid, means to rotate the ball in the body, a sealing ring of hot-flowing resin between said ball and at least one of said flanges, the flange which is downstream in the direction of flow of the fluid having therein a recess defining an annular relief volume, the ball in the closed position of the valve having freedom of displacement within the valve body relative to said valve rotating means in the downstream direction, said body having a metallic seat to receive the ball on the downstream side in the event of elimination of the material of the sealing ring at high temperatures, said valve body containing at least at the downstream end a composite seal for the ball, said seal comprising an annular diaphragm with a metallic core joined to a ring of plastic material which serves as a seat for the ball in normal service, the diaphragm having a projecting annular element which surrounds the ring and is directed toward the ball, said element being so shaped as to form a seat for the ball in the event of elimination of the plastic material of the ring at high temperatures, the recess communicating with said passageway by means of a chamfer which constitutes in conjunction with said passageway a relieving volume for the plastic material in the event of hot flow, the external diameter of the chamfer being larger than the internal diameter of the sealing ring.

Claim 10

A valve according to claim 7, wherein the sealing ring is disposed at least partially within the chamfer in the event of elimination of said ring at high temperatures, any additional quantity being disposed within the flange passageway.