Abstract: Apparatus is disclosed for protecting the end face of an annular blowout preventer or the like from corrosion. In one embodiment, both a ring groove and a circle of tapped stud holes are protected in a low pressure environment by parts on a bell flange to be connected above the annular preventer, and, in another embodiment, the circle of holes is protected in a high pressure environment by the flange of another preventer to be connected above the annular preventer and sealed with respect to the annular preventer by a conventional metal API seal ring.

Abstract: There is disclosed a device comprising a disc for disposal over the outer side of a flange, an annular ridge on the disc for substantially filling a ring groove in the outer side of the flange, a plurality of plugs on the disc for fitting closely within certain holes of a circle of bolt holes through the flange, and fasteners for holding the plugs in the bolt holes.