Patent ID: 8689893
Filing Date: 2014-04-08
Classification: E21B,F16K

Abstract:
1. A check valve comprising a valve housing, a substantially circular flapper, a valve seat for the flapper, an expandable chamber in fluid contact with a connecting port for hydraulics fluid, and a piston having a first and a second end, wherein the flapper comprises a first and a second connection point and is pivotally connected at the first connection point, said flapper being capable of pivoting between a closed position in close contact with the valve seat and an open position which allows fluid to flow through the valve, and wherein the piston is in contact with the expandable chamber and a pre-stressed compressible device, said piston being pivotally connected at the first end to the flapper via the second connection point, characterized in that the compressible device can move the piston in a direction towards the valve seat, that hydraulic fluid can move the piston in a direction away from the valve seat when sufficient hydraulic fluid is supplied through the connection port to expand the chamber, and that the second connection point is situated closer to the center of the circular part of the flapper than the first connection point, such that the flapper comes into close contact with the valve seat when the piston is moved in a direction towards said valve seat and the flapper will pivot around the first connection point in a direction towards the piston when the piston is moved in a direction away from the valve seat.