Developments in Soft Seated Trims for Control Valves

Summary

The long standing and high cost problems of leaking control valves in severe duty liquid applications continues to cause concern, both in terms of losses due to energy wastage and more importantly, damage and failure of valve trims due to wire drawing and cavitation. Failure of valves in this manner can result in costly down time.

Metal seated valves have been found to be unsuitable for these applications and early attempts at soft seated valve trims were only partially effective due to material limitations and the orientation of the soft seats in the valve trims, resulting in water washing of the soft seat during normal flow conditions. Developments have continued in this area of valve design and this paper discusses one of the latest designs of soft seated trim which maintains zero [bubble tight] leakage throughout the service life of the trim. This trim is particularly useful for feed pump recirculation duties and the paper also addresses this application as a follow on to the paper on feed pump recirculation presented at the last BHRA Conference.