| 摘要 |
<p>A filtered stop including a seal assembly having a rotary seal member with flow ports and a stationary seal member with corresponding flow ports, the rotary seal member being selectively positionable by indexing means which are operable from outside the stop so that the flow ports of the rotary seal member may be positioned either into or out of alignment with the ports of the stationary seal member to automatically shut off the flow of fluid before removal of the filter can be accomplished.</p> |
