Abstract: A diaphragm valve which uses a multiple annular metal diaphragm welded about its inner periphery to a valve operating stem. The diaphragm is sealingly clamped about its outer periphery to the valve body and is also clamped about its inner periphery at a location spaced outwardly of the weld to prevent the weld from being subjected to flexure stresses during valve actuation. The actuating assembly is arranged to produce non-rotary, reciprocatory movement of the operating stem through a bonnet mounted rotary actuator. An improved stem tip seal arrangement is also disclosed.