Sealing mechanism for a ball valve

摘要

A seal mechanism in a ball valve in which a valve seat made of an elastic material such as rubber is enforced under pressure into a seat retaining groove defined with a half-groove formed along the outer circumference on the top end of an inner ring and a half-groove formed along the inner circumference on the top end of an outer ring, and the diameter for the sealing point at the corner on the top end along the inner circumferential surface of the valve seat bulging out of the seat retaining groove to be in press contact with a ball-like valve body is made greater than the diameter for the sealing point at the corner on the counter-top end along the inner circumferential surface of the valve seat facing the side wall on the counter-top end of the inner ring that constitutes said half-groove, is improved for the sealing performance under the high fluid pressure condition such that an inner groove is formed at a part on the counter-top end along the circumferential wall of the inner ring that constitutes the half-groove and the counter-top end along the inner circumferential surface of the valve seat is adapted to bulge into the inner groove when a fluid pressure is exerted to the inner ring in the direction of compressing the valve seat.