Diaphragm Valve Stem Assemblies
Diaphragm valves have stems that do not rotate. The valves are available with indicating and nonindicating stems. The indicating stem valve is identical to the nonindicating stem valve except that a longer stem is provided to extend up through the handwheel.
For the nonindicating stem design, the handwheel rotates a stem bushing that engages the stem threads and moves the stem up and down. As the stem moves, so does the compressor that is pinned to the stem. The diaphragm, in turn, is secured to the compressor.