VALVES
Diaphragm Seal, Diffusion-Resistant Valves

Diaphragm seal valves are mandatory for high purity gas handling systems where inboard diffusion of air or moisture must be kept to a minimum. Their packless design maintains gas purity at maximum levels (typical inboard leakage is less than 2 x 10^–8 scc/sec Helium) while permitting operation at pressures ranging from vacuum to 3000 psig. Advanced diaphragm seal valves are available in brass or Type 316L Stainless Steel construction.

The multi-turn version has a hand wheel which operates from “fully closed” to “fully opened” in approximately 3/4 turn. The 1/4-turn version has a lever-type handle which operates from “fully closed” to “fully opened” in a 90° arc. The handle also serves as a visual aid in determining if the valve is open or closed. For example, the valve is open when the handle is parallel to the piping system. The 1/2" NPT diaphragm seal valve can be used on manifolds or systems having higher flow requirements.

Operating Temperature Range:
   -40°F to 140°F

Flow Coefficient:

Inlet and Outlet Connections:

Materials of Construction
Body:
Other Metal Parts Exposed to Gas:
   Brass Valves: Brass and Stainless Steel
   Stainless Steel Valves: Type 316 SS
Seat: PCTFE
Diaphragm: Type 316 Stainless Steel

Table I