Diaphragm valves are frequently of a type having a diaphragm which is unaffected by corrosive fluids and having a resilient backing between the diaphragm and the compressor which transmits the closing force for the valve. BALANCING VALVES Polytetrafluoroethylene (hereinafter TFE) is a usual material for these diaphragms because of its inert properties and a usual backing sheet material is an elastomer. These diaphragm valves are called upon often to operate toward an open position under vacuum and/or high-temperature conditions in the fluid passage.However, high temperatures cause the TFE to soften and reduce its tensile strength. On the other hand, high temperatures cause an increase in the flex resistance of the backing sheet.Balance Valves Further, the opening force is applied by the actuating mechanism directly and solely on a stud which is embedded in the TFE diaphragm. Instrument Manifolds The result has been a short operational life of the diaphragm due to stud pullout under vacuum and high-temperature conditions.

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