Diaphragm valve with actuator bearing element

A diaphragm valve comprising:

• a valve body defining a flow passage extending to an internal valve cavity;
• a valve seat disposed in the valve cavity and surrounding the flow passage;
• a diaphragm disposed in the valve cavity, the diaphragm including an axially fixed outer periphery and an axially flexible central portion movable between a closed position in sealing engagement with the valve seat and an open position axially spaced apart from the valve seat;
• and
• an actuator including an actuator housing assembled with the valve body and an actuating arrangement axially movable within the actuator housing between a first position holding the diaphragm in the closed position and a second position permitting movement of the diaphragm from the closed position to the open position, wherein the actuating arrangement comprises:
• an actuator stem extending through a lower bore in the actuator housing;
• an actuator button disposed between a lower end of the actuator stem and the diaphragm for contact with the diaphragm;
• and
• a bearing member disposed between the actuator stem and the actuator button,
• wherein an upper portion of the bearing member is received in a lower socket portion defined by an annular wall of the actuator stem, and a lower portion of the bearing member is received in an upper socket portion defined by an annular wall of the actuator button;
• wherein one of the upper socket portion and the lower socket portion includes a concave inner face portion, with the bearing member press fit into the one of the upper socket portion and the lower socket portion, and the concave inner face portion providing increased surface contact with a convex portion of the bearing member.