R&D for expanded graphite packing for a quarter turn valve

摘要

In recent years, quarter-turn valves including ball and butterfly valves have increasingly been used in place of gate or globe valves in petroleum, petrochemical and chemical plants. This is mainly because the quarter-turn valves have a small footprint and a short open/close time. Due to this trend shift, valve operating mode has mainly changed from "Reciprocating motion" to "90-degree turn motion". The change of operating mode, however; raised some new problems relating to packings. To cope with these problems, we have developed a new packing featuring a "low sliding resistance" and "high sealing capability" resulting from improvements in cross section structure and inner circumferential surface of the packing. This paper reports on this research and development.