Patent ID: 8291981
Filing Date: 2012-10-23
Classification: E21B

Abstract:
1. A shear open valve, for use in an offshore or onshore well bore, comprising an outer hollow housing with an interior valve seat and an internal body comprising a valve element sealing surface, said internal body being movable in a longitudinal direction within the outer hollow housing, wherein a pre tensioning section is connected to one end of the outer housing, thereby forming a nose of the outer hollow housing, said pre tensioning section comprising a partial threaded recess and a through-going bore, into which partial threaded recess a screw nut is screwed, said screw nut comprising a through-going bore and a receiving area adapted for engaging with a locking arrangement, the through-going bore of the pre tensioning section and the through-going bore of the screw nut being aligned, the shear open valve further comprising an elongated retainer key arranged passing through the through-going bore of the screw nut, said retainer key comprising a first locking arrangement arranged to engage with the receiving area of the screw nut when the shear open valve is in a closed state, the retainer key furthermore being in contact with the internal body in the closed state of the shear open valve such that the valve element sealing surface of the internal body is in abutment with the interior valve seat of the outer housing, whereby an increase in pressure exceeding a predetermined pressure causes the first locking arrangement to disengage from the screw nut, allowing the internal movable body and the retainer key to move through the bores of the pre tensioning section and screw nut towards a stop surface in the pre tensioning section, thereby opening the shear open valve.