Diaphragm valve having a belleville-spring assembly

Abstract

A valve member is axially supported for reciprocal movement within the lower portion of the chamber of a valve housing. The chamber lower portion is sealed from the chamber upper portion by a flexible diaphragm assembly. The valve member includes a cap maintained in abutting relation with the lower surface of the diaphragm assembly. A valve stem is coaxially aligned with the valve member above the diaphragm assembly and includes a head portion that abuts the diaphragm assembly opposite the cap. Downward movement of the valve stem is transmitted through the diaphragm assembly to downwardly move the valve member into sealing relation with the valve seat. The valve is opened by advancing the valve stem upwardly within the chamber. A Belleville spring assembly surrounding the valve member urges the valve member to move away from the valve seat to open the valve. The Belleville spring assembly includes a plurality of parallel arranged spring washers stacked in series relation between a valve guide surrounding the valve member and the cap. The series stack of parallel arranged Belleville washers exerts a preselected thrust upon the valve member to move the valve member through a relatively short stroke and open the valve while maintaining a stabilizing force on the valve member throughout its stroke.