Annular preventer

Abstract

An annular preventer blowout preventer (BOP) that can seal off a wellbore for controlling and monitoring oil and gas wells. The BOP is a latch type annular preventer with a body, a inner, a piston, and a rubber packing element. The preventer seals around drill pipe and in some instances against an open well bore. A plurality of latches and inner screws secure the lid to the body and further prevent rotation.

What is claimed is: 
     
         1 . An annular preventer, comprising
 a body defining a throughbore;   a lid that fits onto said body, said lid comprising a replaceable wear plate, said lid and said body defining a chamber therein with a first interior cylindrical surface within said lid and a second interior cylindrical surface within said body;   a plurality of latches mounted around a circumference of said body that extend through said body, said plurality of latches comprising retractable jaws that engage corresponding latching surfaces on said lid to selectively secure said lid to said body;   a conical packing element comprising an opening therethrough operable to receive a pipe extending through said throughbore, said pipe when present defining an annulus between said throughbore and said pipe;   a piston mounted in said body for movement in an axial direction parallel to an axis through said throughbore, said piston defining an interior conical receptacle that receives said conical packing element, said piston comprising an exterior piston member that moves within an annular piston chamber formed between said piston and said body, said piston comprising a first exterior cylindrical surface and a second exterior cylindrical surface that engage said first interior cylindrical surface and said second interior cylindrical surface;   a cage that engages said conical packing element to secure said conical packing element between said cage and said replaceable wear plate;   hydraulic connections on either side of said exterior piston member that extend through said body, said piston being movable in said axial direction in response to hydraulic fluid to selectively compress said conical packing element to seal said annulus around said pipe; and   a plurality of cap screws that extend through said lid to engage said body to prevent rotation of said lid with respect to said body.   
     
     
         2 . The annular preventer of  claim 1 , further comprising a flange on said lid, said plurality of cap screws extending through said flange. 
     
     
         3 . The annular preventer of  claim 2 , further comprising a top surface of said body that engages said flange. 
     
     
         4 . The annular preventer  claim 1 , further comprising a seal on said on said exterior piston member that engages a cylindrical piston chamber wall. 
     
     
         5 . The annular preventer of  claim 1  wherein said throughbore comprises a diameter of 7 1/16 inches. 
     
     
         6 . The annular preventer of  claim 1 , wherein each latch of said plurality of latches further comprises an outer screw disposed within said latch which passes through said body, said outer screw being threaded, a socket head on a terminal end of said outer screw outside relative said body whereby upon rotation of said socket head rotates said outer screw along an axis inward and outward relative said body, a seal mounted around said outer screw which seals said outer screw within said body when engaged, an inner screw mounted internally within said outer screw, said inner screw being operably attached to said retractable jaw, a second seal mounted within said inner screw which seals with said outer screw, said retractable jaws further comprise an internal set of teeth moveably mounted within said body, a corresponding external latching surface formed on said lid whereby said corresponding external latching surface comprises an external set of corresponding teeth operable to receive said internal set of teeth from said retractable jaw to secure or loosen said body and said lid. 
     
     
         7 . The annular preventer of  claim 6 , further comprising a shoulder between said outer screw and said inner screw whereby rotation of said outer screw and engagement at said shoulder urges of said outer screw radially outward to retract said internal set of teeth from said external set of corresponding teeth.