| 摘要 |
<p>A flow control device (30) having a first port (34), a secondρort (66), a third port (36) and the movable member (42). In a first mode, the movable member seals the second port while allowing fluid flow between the first and third ports, wherein the differential pressure between the first port and third port, during the first mode, is about zero. In the second mode, the movable member seals the first port while allowing fluid flow between the third port and second port, wherein the movable member is adapted to transition from the first mode to the second mode in response to a small change in differential pressure.</p> |
