The operation of a diaphragm valve is generally by a hand wheel device screwing down a stem with a saddle on the end, which in turn forces an elastomeric diaphragm on to a polished surface inside the valve body. Diaphragm valves can be either "weir" type or "full bore" type configurations. Energisation of the seal is purely by mechanical force, applied by the hand wheel through the screwed stem and saddle.
The primary function of a diaphragm valve is for isolation. Diaphragm valves are susceptible to erosion / flow damage and should therefore not be used for flow control or throttling applications.
|Common Materials of Construction||Material Specifications|
|Standard Carbon Steel||ASTM A105|
|Low temperature Carbon Steel||ASTM LF2|
|Stainless Steel||ASTM A182 F316|
ASTM A182 F316L
ASTM A182 F304
ASTM A182 F304L
ASTM A182 F321
ASTM A182 F347
ASTM A351 CF8M
ASTM A351 CF3M