| 摘要 |
<p>A pressure flow valve (1) for controlling fluid flow in well tubing comprises a tubular body (2) provided with at least one flow port (3); fluid control means in the form of sleeve (4) moveable relative to the tubular body (1) from a first position in which fluid can flow into the tubular body via the flow port, to a second position in which the control means seals the flow port; biasing means in the form of spring (5) and chamber (6) for moving the fluid flow control means towards the first position when the fluid pressure differential between fluid present in the tubular body and fluid outside the tubular body is negative, and moving the control means towards the second position when the pressure differential is positive; and locking means (7) connected to the control means for retaining the control means in the second position once the flow port (3) has been closed. <IMAGE></p> |
