Enrique L. Kilayko - Weston MA
A ball check valve assembly for chemical pumps. A fluid conduit terminates at a first surface in a port of circular cross section. Within the conduit, an O ring seat is aligned with the port; an elastomeric O ring is positioned in the seat. Spacer means, radially outward of the O ring seat, extends generally away from the port and has a dimension adjacent the O ring seat greater than the cross sectional diameter of the O ring when unstressed. O ring capture means spaced from the O ring seat limits travel of the O ring away from the port, and provides a central aperture for the valve ball, which has a diameter greater than that of the port. The O ring has an ID less than the diameter of the ball and an OD greater than the diameter of the aperture; the spacer means ID is at least about 1/2% greater than the OD of the O ring. During closing travel of the ball, the O ring is free to move transverse to the direction of such travel responsive to the ball, for impact on the O ring distributed relatively equally over the contacted surface.