Abstract: The invention relates to apparatus and a method for assembling a thermostatic type bellows unit of the type having a cup shaped bellows housing and disposed in spaced relation thereto a corrugated cup shaped diaphragm having a rigid annular flange. The assembling involves pressure welding the diaphragm flange to the housing. The apparatus includes a bottom electrode having a chamber for receiving and supporting the bellows unit and an upper electrode having a central projection which protrudes into the diaphragm and a surrounding collar for biasing the diaphragm flange into abutting engagement with the upper edge of the housing. A suction system including a passage in the electrode projection provides a partial vacuum for drawing the diaphragm into engagement with said upper electrode projection. The chamber is then flushed with a flushing medium.

Abstract: The invention relates to a method for making a thin walled diaphragm unit of the type used in pressostats and thermostats. The method involves attaching a ring element to one end of a tubularly shaped diaphragm element which may have the bellows forming corrugations formed thereon either before or after the attachment of the ring element. Electrodes are utilized for physically pressing the parts together as well as providing for a flow of current through the joint to provide a metallurgical joining of the parts. A layer of an alloy of phosphorous and nickel is applied to the ring element which results in a heat joining of the parts which in effect is between soldering and welding.