| 摘要 |
<p>A VALVE TYPICALLY USED IN AN OIL OR GAS WELL, HAVING A MOVEABLE MEMBER (5) SUCH AS A BALL MOVABLE BETWEEN OPEN AND CLOSED CONFIGURATIONS AND HAVING A CUTTING DEVICE ARRANGED TO SHEAR AGAINST AN ANVIL MEMBER (15) WHEN THE BALL IS MOVING BETWEEN THE OPEN AND CLOSED CONFIGURATIONS; AND HAVING A SEALING MEMBER (10) PROVIDING A SEAT FOR SEATING OF THE MOVEABLE MEMBER (5) WHEN THE MOVEABLE MEMBER (5) IS IN THE CLOSED CONFIGURATION. THE ANVIL MEMBER (15) AND THE SEALING MEMBER (10) ARE MOVEABLE RELATIVE TO ONE ANOTHER WHEN THE MOVEABLE MEMBER (5) IS MOVING FROM THE OPEN TO THE CLOSED CONFIGURATION, SO THAT DURING OPENING AND CLOSING THE SEALING MEMBER (10) IS DISPLACED AWAY FROM THE CUTTING DEVICE (TYPICALLY THE INNER SURFACE OF THE BORE) AS THE CUTTING DEVICE ENGAGES THE ANVIL MEMBER (15). THE SEALING MEMBER (10) IS PUSHED AWAY FROM THE MOVEABLE MEMBER (5) AND THE ANVIL TO A MAXIMUM SEPARATION FROM THE MOVABLE MEMBER (5) AT THE POINT ON THE STROKE WHEN THE CUTTING SURFACE OF THE MOVEABLE MEMBER (5) IS MOVING PAST THE ANVIL MEMBER (15), SO THAT THE SEALING MEMBER (10) IS MOVED OUT OF CONTACT WITH THE BALL WHEN THE CUTTING SURFACE ENGAGES THE ANVIL MEMBER (15), AND MOVES BACK INTO CONTACT WITH THE BALL WHEN THE CUTTING SURFACE HAS PASSED THE ANVIL MEMBER (15) AND THE SEALING SURFACE OF THE BALL IS ALIGNED WITH THE SEALING MEMBER (10).</p> |
