Patent ID: 8668015
Filing Date: 2014-03-11
Classification: E21B,Y10T

Abstract:
1. A valve for use in a drill string, the valve comprising: a housing having an inner wall; a sleeve disposed within the housing with a gap between the inner wall and the sleeve, the gap having a width; a first check valve positioned within the housing, the first check valve including a piston, the piston being axially movable between an open position in which the piston is outside the gap and a closed position in which a portion of the piston extends into the gap, the piston being biased to the closed position; in which the piston includes an annular shoulder facing towards the sleeve, and in which, in the closed position, with the portion of the piston extending into the gap, the shoulder on the piston abuts against the sleeve outside of the gap; the portion of the piston that extends into the gap having parallel sides and extending across the width of the gap in the closed position, and the parallel sides terminating in a tapered surface, the tapered surface in operation of the valve, redirecting abrasive flows in the gap when the first check valve is in the open position; a second check valve positioned within the sleeve, the second check valve being positioned in parallel to the first check valve; in which the first check valve and the second check valve are oriented to block flow in opposite directions; and in which the fluid flowing through the valve is contained entirely within the housing.