Anodic Protective Seal in a Blowout Preventer

Abstract

An anodic sacrificial seal element is installed at vulnerable regions of a blowout preventer. A zinc cylinder, for example, is included at the well-bore pressure side of a bonnet which seals around a rod as it extends through a bonnet which joins an actuator to the body of the BOP. Similarly, a zinc O-ring may be used in a seal groove provided between the bonnet and the body of the BOP. In this way, the high electropotential of the material from which the additional seal element is made is oxidized first, before any attack on the BOP material, thereby increasing the time period between maintenance events on the BOP.

1 . A blowout preventer actuator assembly joined to a blowout preventer body, the assembly comprising: 
 a bonnet;    a cylinder body coupled to the bonnet and enclosing a cylinder chamber having a piston therein;    a rod connected to the piston at one end and to a ram head at the other end; and    a first anodic seal element between the bonnet and the rod.    
   
   
       2 . The assembly of  claim 1 , wherein the first anodic seal element is made of zinc.  
   
   
       3 . The assembly of  claim 1 , further comprising a first pressure seal element adjacent the first anodic seal element.  
   
   
       4 . The assembly of  claim 1 , wherein the first anodic seal element defines a cylinder.  
   
   
       5 . The assembly of  claim 1 , further comprising a second anodic seal element between the bonnet and the blowout preventer body.  
   
   
       6 . The assembly of  claim 5 , wherein the second anodic seal element is made of zinc.  
   
   
       7 . The assembly of  claim 5 , wherein the second anodic seal element is made of a material having an electropotential higher than the material from which either the bonnet or the rod are made.  
   
   
       8 . The assembly of  claim 5 , further comprising a second pressure seal element adjacent the second anodic seal element.  
   
   
       9 . The assembly of  claim 8 , wherein the second pressure seal element and the second anodic element are each formed in the shape of a ring.  
   
   
       10 . A seal element between first and second metal components comprising an anodic member having an electropotential higher than either of the first and second metal components and positioned adjacent a pressure seal element.