| 摘要 |
<p>VALVE HAVING HARD AND SOFT SEATS An improved valve is provided of the type having a spring biased ball for sealing engagement with both a metallic seat and a plastic seat. The valve is of the type including a passageway adapted for receiving a stinger to unseat the ball from both seating surfaces, thereby allowing fluid to pass through the valve body. The diameter of the soft seat approximates the diameter of the ball, and preferably at least a portion of the sealing surface of the soft seat is spaced opposite the metallic seat with respect to a plane parallel to the metallic seat and passing through the center of the fully seated ball. The soft seat may be secured in the valve body by a retainer, which maintains a radial outwardly directed force on the soft seat.</p> |
