Diaphragm Valve Stem Assemblies:

Diaphragm valves have stems which do not rotate. The valves are available along with indicating and nonindicating stems. An indicating stem valve is identical to the nonindicating stem valve except which a longer stem is given to extend up by the handwheel. For the nonindicating stem design, the handwheel rotates a stem bushing which engages the stem threads and moves the stem up and down. Since the stem moves then so does the compressor which is pinned to the stem. The diaphragm within turn is secured to the compressor.