| 摘要 |
An improved plug valve is of the type that includes a valve body having a bore extending therethrough and a pair of passages intersecting the bore and being substantially normal to the axis of the bore. a valve plug is disposed within the bore for selective rotation between an opened and a closed position to respectively align and misalign a port through the plug with the passages. A first circumferential sealing member between the plug and the bore above the port and the passages and a second circumferential sealing member between the plug and the bore below the port prevents fluid from escaping from an interior of the plug valve and balances fluid pressure acting on the plug. The improvements include providing opposed circumferential semicircular grooves respectively on the bore and the plug to define a circumferential channel therebetween. The body includes a circular hole extending therethrough which is tangentially aligned with the channel. A flexible rod extends through the hole and around the channel for retention of the plug within the bore. A bottom insert is fitted within the bore to enclose the base of the plug within the body and allows fluid to escape from below the plug if the second sealing member should fail. A circumferential sealing device around the top of the plug prevents ingress of foreign matter into the region of the bore above the first sealing member. |
