Ball closure for pipeline valve - uses dual seals with smaller of harder material and contacting ball at two positions

摘要

The ball tap has a housing fitted with flow pies, and inside it is a rotatable cut-off ball arranged between soft seals in the vicinity of the pipes. Through the ball at right angles to its rotary axis is a flow path, and the ball can be moved between a pipe open position and one where the flow path is cut off. The effective sealing dias. of the two seals (22, 23) accommodating the cut-off ball (14) are different. The seal (23) with the smallest dia. is of harder material than the other (22).