Ball check valve

Claim 1

A check valve for permitting fluid flow in one direction and preventing fluid flow in the reverse direction comprising: a. a tubular body having a longitudinal flowbore therethrough with inlet and outlet; b. a removable annular seat within said flowbore facing in said one direction, and removable seat retainer means for constraining said seat in said flowbore; c. a cylindrical pocket communicating with said flowbore through an opening, the axis of which pocket is inclined relative to the axis of said flowbore; d. a ball member carried by said body and movable, by fluid flow, into said pocket, when fluid flows through said valve in said one direction, to permit flow therethrough, and movable, under the influence of gravity, into sealing engagement with said seat in said flowbore, to block reverse fluid flow therethrough; e. deflection means within said flowbore for guiding said ball member between said pocket and said flowbore including a cylindrical guide path formed by the intersection of said flowbore with the cylindrical projection of said pocket, said flowbore downstream of said intersection being of a diameter smaller than the diameter of said ball member; and f. a side port in said body, and closure for said port, said side port extending from the exterior of said body to said flowbore, and permitting, upon removal of said closure, removal of said ball, seat retainer means and seat through said side port.