| 摘要 |
<p>A retrofit second packing chamber for quarter-turn valves that permits existing valves to be modified so as to meet modern emission standards without requiring replacement of the valves, and which can be assembled to exist ing valves in a simple, efficient manner at reasonable cost. The retrofit second pac king chamber comprises an assembly which defines a second packing chamber to be assembled to the existing first packing chamber of a valve in series therewith s o as to substantially increase the protection against undesired emissions from the va lve.</p> |
