Axial flow turbine drill for earth boring

Claim 1

In an earth-boring drill comprising in combination: a dualconduit drill pipe having an outer drill pipe and a concentric inner pipe secured therein, said outer drill pipe and said inner pipe forming a pipe annulus therebetween, said dual-conduit drill pipe made in composite lengths which are adapted to be joined end to end to form a long string of dual-conduit drill pipe; a drilling bit having a hollow shank and fluid flow channels threadedly attached to the lower end of the dual-conduit drill pipe assembly, said bit adapted to bore into the earth when rotated under mechanical pressure to produce a borehole; the wall of said borehole and said outer drill pipe forming a borehole annulus therebetween, when the said dual-conduit drill pipe is in the hole; a drilling fluid under pressure introduced at the earth''s surface into the said drill pipe annulus, thence flowing downwardly through said drill pipe annulus, thence through said flow channels in said bit, thence upwardly in said bit''s hollow shank, thence upwardly in the said inner pipe to the earth''s surface, carrying therewith any cuttings, or cores, formed by the said bit; the improvements for rotating said bit and for applying weight on said bit, said improvements comprising: an axial flow turbine motor inserted in the dual-conduit drill pipe string above said bit, said turbine motor motivated by the said fluid flow in the said drill pipe annulus, said turbine motor comprising an outer turbine stator barrel rigidly inserted in the said dual-conduit drill pipe string and forming a part thereof; and an inner, rotatable, hollow rotor spindle, serving as a continuation of the said concentric inner pipe; said rotor spindle positioned opposite the said stator barrel by flow-passing radial bearings, said turbine barrel and said turbine spindle forming a turbine annulus therebetween, which turbine annulus is a continuation of said drill pipe annulus, said flow-passing radial bearings being positioned in said turbine annulus and said drill pipe annulus; the upper end of said rotor spindle rotatably sealed to the next above said concentric inner pipe be rotation permitting seal means, the lower end of thE said turbine rotor having a downward, tubular spindle extension that is threadedly connected to the inside top of said bit''s hollow shank to transmit rotation to said bit by said turbine rotor, the said turbine rotor and said downward tubular spindle extension being free of any compression, and free to move longitudinally within narrow limits to maintain a compression free condition; the required weight on the said drill bit impressed thereon by the weight of the dual-conduit drill pipe string, or portion thereof, the said required weight being transmitted downwardly through the said turbine barrel, thence downwardly through a downward tubular extension of said turbine barrel, thence through a low-friction thrust bearing, which bearing is mounted on the top of said bit sub and external of the said tubular extension, thence through the said bit sub to the said bit.