Structure maintaining seats against ball valves

Claim 1

A ball valve assembly comprising a valve body having a fluid conducting passageway therethrough, the passageway comprising a high pressure side; a ball valve mounted for rotation within the valve body to selectively allow or prevent the passage of fluid through the passageway; means defining an annular recess in said valve body adjacent said ball and in operative communication with said passageway; means defining a volume between said ball and body on the opposite side of said recess from said passageway, said volume comprising a low pressure side; an annular valve seat of rigid material disposed in said recess; and a solid elastic material annular body disposed in said recess to bias said valve seat into tight sealing engagement with said ball; wherein the assembly is operative over a wide range of temperatures, is solids proof, and can maintain large pressure differentials, and further comprises: surface means, provided on facing surfaces of said valve body defining said recess and said valve seat, for defining a region between said valve body and said valve seat having a larger cross-sectional area at the high pressure side thereof than at the low pressure side thereof with a transition therebetween said surface means converging toward each other along said transition; and wherein said solid elastic material body is disposed in said region and provides means for positively elastically engaging said surface means along said transition upon application of high pressure to said high pressure side of said region.