| 摘要 |
<p>Apparatus 10 for receiving the discharge of flowable material from a store thereof, comprises a hollow support member 16, a through-flow device 18 slidable within the hollow support member 16 and into which material from the store can flow, and fluid actuation means for moving the through-flow device 18 relative to the hollow support member 16. The fluid actuation means comprises a variable volume chamber 56 into and out of which fluid can flow in order to move the through-flow device, and a rolling seal 60 for preventing undesirable escape of the fluid from the variable volume chamber 56. The in use rolling seal 60 rolls without sliding as the through-flow device 18 moves, so that frictionless or substantially frictionless movement of the through- flow device 18 occurs.</p> |
