| 摘要 |
<p>A valve, such as a ball valve, comprises a body (10) with a through passageway (11) characterized in that an internally restrictive frustoconical seat (13) is provided with a frustoconical metallic back-up member (15) having a different cone angle than the seat (13) and a larger diameter ball (20) having a maximum diameter greater than the maximum diameter of the back-up member (15), the back-up member having a contoured large diameter axial end face for receipt of a portion of the ball such that a seal is provided between the seat and the ball and between the back-up member and the seat and means urging the ball against the back-up member large diameter axial end and the back-up member against the seat.</p> |
