Deformation resistant opening chamber head and method

摘要

An annular blowout preventer device includes a body and a static head removably connected to the body, A piston is disposed inside an opening chamber to squeeze a packer. An opening chamber head has a rib extending upward from an upper surface. The rib is received within a recess in the lower surface of the static head.

主权项

1. A blowout preventer, comprising:
a body having a bore with an axis for the passage of a well pipe; a static head that secures to an upper end of the body; an annular opening chamber in the body; an annular piston having an outer portion carried in the opening chamber for axial movement, the piston having an inner portion that defines an inner wall of the opening chamber; an annular packer element carried in the bore and engageable by the inner portion of the piston as the piston moves upward for closing around the well pipe; an opening chamber head located in the opening chamber above the outer portion of the piston and circumscribing the inner portion of the piston, the opening chamber head having an outer portion in sealing engagement with an inner surface of the body and an inner portion in sliding and sealing engagement with an outer surface of the inner; portion of the piston, the opening chamber head having an upper surface with at least one annular rib protruding upwardly therefrom, the opening chamber head having a lower surface that is abutted by the outer portion of the piston while the piston is in an upper position; the static head having a lowermost surface located in a plane perpendicular to the axis, the lowermost surface having at least one annular recess into which the at least one annular rib extends, the at least one annular recess having concentric inner and outer walls extending upwardly from the lowermost surface of the static head, the at least one annular rib extending between and in engagement with the pair of concentric walls such that the pair of concentric walls are operable to provide lateral support on inner and outer sides of the at least one annular rib; the lower surface of the opening chamber head has a downward and outward extending conical surface with a lowermost portion that terminates adjacent the outer portion of the opening chamber head; and the outer portion of the piston has an upper surface with a downward and outward extending conical surface that terminates adjacent an outer surface of the outer portion of the piston for mating with the conical surface on the lower surface of the opening chamber head.