Patent ID: 9593779
Date: 2017-03-14
CPC Classifications: B23P,F16J,F16K,Y10T

Claim:
1. A ball valve comprising: an inlet and an outlet with a flow path for fluid therebetween; a rotatable ball positioned in the flowpath, wherein the flow of fluid along the flowpath is dependent on the rotation of the ball; a first bellow arranged between the inlet and the ball, wherein the first bellow is fixed in a housing under compression so that a mechanical seal is maintained between a seat of the first bellow and the ball; and a second bellow arranged between the outlet and the ball, wherein the second bellow is fixed in the housing under compression so that a mechanical seal is maintained between a seat of the second bellow and the ball; a stem that extends from first and second sides of the ball; a third bellow arranged around the stem extending from the first side of the ball, wherein the third bellow has an integral seat in contact with the ball; and a fourth bellow arranged around the stem extending from the second side of the ball, wherein the fourth bellow has an integral seat in contact with the ball; wherein the third and fourth bellows have longitudinally elastic properties and are fixed in the housing under compression such that the compression in the third and fourth bellows ensures a mechanical seal between the seats of the third and fourth bellows and the ball; wherein at least the third bellow comprises a polymeric material seal between the stem and a plug of the third bellow and the stem extends through the polymeric material seal out of the housing; wherein the polymeric material seal is arranged in the housing so that fluid from the main flow path can only reach the polymeric material seal if the fluid leaks across at least the mechanical seal between the seat of the third bellow and the ball; wherein each of the first and second bellows comprises: a seat, which is metallic, at an end of the bellow for providing a contact surface with the ball of the ball valve; and