Method of making a diaphragm valve

Abstract

The method of producing a cage unit for mounting a metal diaphragm in a hermetically sealed diaphragm globe valve having a valve body and bonnet of forged austenitic stainless steel in which the diaphragm unit consists of 8 to 12 very thin (0.006"-0.008") Inconel 718 discs so that the cage unit can be installed by welding, in the field, to the bonnet without requiring any special skills; the cage unit supporting the metal diaphragm and being compatible to being welded to the forged austenitic stainless steel and comprising a pair of annular metal retaining rings situated on opposite sides of the plural-disc, metal diaphragm which is squeezed therebetween; the retaining rings including heat-sink portions about the outer peripheries, and the cage unit, when welded in the bonnet of the valve, preventing leakage to the atmosphere of liquids passed through the valve in which the method comprises the steps of: stacking a plurality of thin metal discs; sandwiching the stacked discs between annular members and applying a peripheral weld completely around the discs and annular members forming a peripherally sealed cage unit; deforming the sandwiched discs to a selected contour; heat treating the cage unit and stress relieving the discs; orienting the cage unit in a valve bonnet and peripherally welding one of the annular members to the bonnet and forming a sealed joint therebetween.

Dependencies are inferred from the claim text.