John Baxter, Swagelok Company, Solon, OH, USA 

ABSTRACT 

Perfluoropolyether fluids are being increasingly used as coolants in heat transfer systems for semiconductor applications. However, some users have encountered seal problems with these fluids, resulting in leakage, which is expensive. These problems have been traced to the dynamic O-ring seals in the plug valves commonly used. This article describes a solution to this problem, based on a ball valve with silicone flange seals.