DEVELOPMENT OF A CRYOGENIC GATE VALVE WITH ROBUST SEALING

A soft-seal cryogenic gate valve has been designed, fabricated, and demonstrated by the Cryogenics Test Laboratory (CTL) at the Kennedy Space Center (KSC), featuring a robust sealing technology and a high flow coefficient (Cv). The robust seal design incorporates novel retracting seal-retaining disks to prevent soft-seal abrasive wear and damage from the valve body hard seat. Advanced materials were incorporated into the design, including fluorinated ethylene propylene (FEP) standard seal material and porous sponge polytetrafluoroethylene (PTFE) optional seal material. Titanium nitride coating was applied to the 316 stainless-steel surfaces that are subject to wearing or galling. The valve is suitable for applications from ambient temperature down to liquid nitrogen temperature (77 K), with a seat leakage rate of less than 1 standard-cubic-centimeter-per minute (sccm) per inch of valve diameter. The very low seat leakage, throttling capability, and high flow coefficient (Cv) of the valve make it suitable for block valve applications on standard to very large cryogenic storage tanks or other applications requiring highly reliable full flow cryogenic valves.