Diaphragm valve construction

Claim 1

A valve comprising in combination: a valve body having an internal through passage with a weir disposed intermediate the ends thereof, said valve body having an opening positioned above said weir; a bonnet affixed to said body in surrounding relation to said opening; a valve actuator carried by said bonnet and reciprocal inwardly toward and outwardly away from said weir; a flexible diaphragm overlying said opening, the upper surface of said diaphragm being connected to said actuator for movement therewith, such that the underside of said diaphragm may be moved inwardly into engagement with said weir in blocking relation to said passage to define a valve closed condition, or moved outwardly away from said weir to define a valve open condition upon reciprocal movement of said actuator; and a plate member disposed intermediate said diaphragm and said bonnet in engagement with the upper surface of said diaphragm, said plate member including an outwardly flared portion terminating with an outwardly facing peripheral edge, said flared portion defining a centrally disposed aperture for permitting outward flexing of said diaphragm, said peripheral edge of said flared portion defining a shoulder along at least a portion thereof; abutment means carried by said actuator for engagement with said shoulder to limit inward movement of said actuator to prevent overcompression of said diaphragm against said weir, said flared portion permitting said diaphragm to flex outwardly upon movement to the open condition, and thereafter under the influence of line pressure, without presenting to said diaphragm, a sharp edge capable of damaging the same.