Importance

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Abstract

A turbodrill which is connected to a string of drill pipe as a rotating shaft for driving a drill bit which may be a rotary bit or a high speed solid head diamond bit. The turbine section has rotor and stator blades which are cresent shaped in cross section with each blade having an exit angle of 14.degree.-23.degree. for maximum turbine efficiency. The bearing shaft is provided with chevron rotary seals positioned below the rotary bearings carrying both radial and vertical thrust. Fluid lubricant fills the space from the rotary seals to a predetermined level above the bearings. A piston seals the lubricant chamber and is pressurized by drilling fluid (i.e. mud) flowing through the tool. A layer of lubricant fluid overlies the first piston and has a second piston covering said fluid and transmitting pressure from the drilling fluid to the lubricant fluid surrounding the bearings. Rubber friction bearings which are cooled and lubricated by flow of drilling mud are provided between the rotor and stator bearing surfaces which provide for extended rotor bearing life and cushion the radial thrust bearings against radial shock and provide for a substantially extended life for the radial thrust bearings.

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First Claim