Cutters for severing objects in bores

Abstract

Cutters for severing objects in a bore. The cutters having a planar body with an opening passing from a top surface through a bottom surface, with the opening encircled by the body. A cutting edge is disposed on a side of the opening proximate a back end of the body. The cutting edge having a layer thereon to sealingly cover the edge. The body is configured for placement with the opening coincident with a bore in a housing and for movement across the bore. The body is configured to receive a propelled member to make contact with the body to transfer kinetic energy from the member to the body to move the body across the bore for the cutting edge to pass through the layer thereon and sever any object in the bore. A method for severing objects in a bore.

1 . A blowout preventer, comprising:
 a main body having a through bore;   an insert disposed in the main body;   the insert having a first segment and a second segment defining a passage between the segments oriented transversely to the through bore;   each of the first segment and the second segment having an opening coincident with the through bore;   a cutter disposed in the passage and configured for severing objects in the through bore, the cutter comprising:
 a planar body having a top surface, a bottom surface, a front end, and a back end; 
 the planar body having an opening passing from the top surface through the bottom surface, wherein the opening is encircled by the planar body; 
 a cutting edge disposed on a side of the opening proximate the back end of the planar body; 
 the planar body configured for placement with the opening coincident with the through bore; and 
 wherein the planar body is configured to receive a propelled member to contact the body to propel the planar body across the through bore for the cutting edge to sever any object in the through bore. 
   
     
     
         2 . The blowout preventer of  claim 1  wherein the cutter planar body comprises holes or voids formed on the body apart from the opening. 
     
     
         3 . The blowout preventer of  claim 1  wherein the cutter cutting edge comprises at least one protrusion extending away from the cutting edge. 
     
     
         4 . The blowout preventer of  claim 1  further comprising a shearable pin extending from one of the top surface or the bottom surface of the cutter planar body. 
     
     
         5 . The blowout preventer of  claim 1  wherein the cutter cutting edge comprises one of polycrystalline diamond or cubic boron nitride. 
     
     
         6 . The blowout preventer of  claim 1  wherein the propelled member consists of a gate configured for gas propulsion into contact with the back end of the planar body to propel the planar body across the through bore. 
     
     
         7 . (canceled) 
     
     
         8 . A method for severing objects in a bore, comprising:
 placing a cutter within an insert in a blowout preventer having a housing with a through bore;   the insert having a first segment and a second segment defining a passage between the segments oriented transversely to the through bore;   each of the first segment and the second segment having an opening coincident with the through bore;   the cutter placed with an opening on the cutter coincident with the through bore in the housing, the cutter including:
 a planar body having a top surface, a bottom surface, a front end, and a back end; 
 the opening passing from the top surface through the bottom surface, wherein the opening is encircled by the planar body; 
 a cutting edge disposed on a side of the opening proximate the back end of the planar body; 
 and 
   propelling a member within the housing to contact the body to propel the planar body across the bore for the cutting edge to sever any object in the bore.   
     
     
         9 . The method of  claim 8  wherein the member consists of a gate configured for travel within the housing to transfer kinetic energy to move the planar body across the through bore. 
     
     
         10 . (canceled) 
     
     
         11 . A blowout preventer, comprising:
 a main body having a through bore;   an insert disposed in the main body;   the insert having a planar upper segment and a planar lower segment defining a passage between the segments oriented transversely to the through bore;   each of the upper segment and the lower segment having an opening coincident with the through bore;   each of the upper segment and the lower segment having a seal arrangement to restrict fluid flow between the through bore and the passage;   a cutter disposed in the passage, the cutter comprising:
 a planar body having a top surface, a bottom surface, a front end, and a back end; 
 the planar body having an opening, wherein the body is configured for placement with the opening coincident with the through bore; 
 a cutting edge on a surface of the opening in the planar body; and 
 wherein the planar body is configured to move across the through bore for the cutting edge to sever any object in the through bore. 
   
     
     
         12 . The blowout preventer of  claim 11  wherein the cutting edge comprises a layer disposed thereon to sealingly cover the edge. 
     
     
         13 . The blowout preventer of  claim 11  wherein the cutting edge comprises at least one protrusion extending away from the cutting edge. 
     
     
         14 . The blowout preventer of  claim 11  further comprising a shearable pin extending from one of the top surface or the bottom surface of the cutter planar body. 
     
     
         15 . The blowout preventer of  claim 11  further comprising a gate configured for movement along the passage to contact the cutter planar body to propel the planar body across the through bore. 
     
     
         16 . The blowout preventer of  claim 15  further comprising a charge disposed thereon and configured to produce a rapid gas expansion when activated. 
     
     
         17 . The blowout preventer of  claim 16  wherein the gate is configured for propulsion via the rapid gas expansion to propel the cutter across the through bore. 
     
     
         18 . The blowout preventer of  claim 11  wherein the seal arrangement in each of the upper segment and the lower segment comprises a seal disposed in a channel formed in the segment. 
     
     
         19 . The blowout preventer of  claim 18  wherein each seal in each of the upper segment and the lower segment comprises a surface facing the passage. 
     
     
         20 . The blowout preventer of  claim 18  wherein each seal in each of the upper segment and the lower segment is positioned on the segment with a central opening in the seal coincident with the through bore.