A downhole drilling motor includes a motor housing having an inner bore and an outer surface. A power section includes a stator elastomer at least partially disposed within the inner bore of the motor housing. A bearing section includes an upper bearing at least partially disposed within the inner bore of the motor housing. The motor housing further includes an opening extending from the inner bore to the outer surface to provide a bypass fluid path for a fluid in the inner bore. The opening is disposed on the motor housing between a lower end of the stator elastomer and an upper end of the upper bearing. The bypass fluid path allows the downhole drilling motor to accommodate a higher flow rate of a fluid through the stator elastomer of the power section than through the upper bearing of the bearing section.

A harmonic drive assembly and fluid-powered linear motors with both axial pistons are rotary piston arrangements incorporating the harmonic drive assembly are disclosed. The motors may be used in downhole drilling applications, but the drive assembly and/or motors may be used in other applications. The assembly, motors and methods use advanced harmonic drives, advanced helical drives, and combinations thereof with 1) motors with axial pistons and reciprocating linear rings to convert reciprocative axial motion to continuous rotary motion, and 2) motors with rotary pistons and reciprocating linear rings to rectify reciprocative rotary motion to continual rotary motion to improve performance over prior configurations. Axial pistons provide a robust simple solution for generating rotation; Rotational pistons provide increased torque generation as the torque generated is proportional to motor length. Since downhole drills are long, a high-torque motor can be produced using this method.

A method for forming a seal boot includes forming a stack of discrete, non-intertwined layers by layering a sheet of elastomeric material with a fabric; rolling the stack to form a tube; installing the tube within a mold; closing the mold; and heating the mold and the installed tube.

The invention relates to a rotary drive arrangement for a drill rod having an outer pipe and an inner rod running at least in sections inside the outer pipe, in particular for double-head and/or overburden drilling, with a first gearbox for driving the inner rod in a rotating manner and a second gearbox for driving the outer pipe in a rotating manner, wherein the first gearbox and the second gearbox are independent of each other. According to the invention provision is made in that the first gearbox and the second gearbox are supported in a common gearbox housing and are surrounded by the same.

The disclosure belongs to the technical field of engineering construction, and particularly relates to a square pile construction method and equipment of a rotary drilling rig. The specific technical solution concerns a square pile construction method of a rotary drilling rig which includes: site leveling; surveying and setting out; creating concrete retaining wall of wellhead; putting the drilling rig in place; adjusting the verticality of the drilling rig; lead hole drilling; reamed hole drilling; square hole drilling; hole cleaning with round drill bit; and hole cleaning with square drill bit. The square pile construction method and rotary drilling rig can use equipment for square pile construction in the whole process, effectively reduce the underground operation of laborers, and avoid the project safety production risk from the source. The disclosure also provides three kinds of square pile drill bits and a square pile hole cleaning drill bit in cooperation with the square pile construction method, which further realizes the mechanization of the whole process of square pile construction.

A seal assembly in an apparatus including a housing, a housing bore defined by the housing, a shaft extending through the housing bore, and a shaft bore defined by the shaft. The housing bore includes an annular seal chamber between the housing and the shaft. The seal assembly includes a flexible tubular seal surrounding the shaft within the seal chamber. The tubular seal has a shaft end sealingly connected with the shaft and a housing end sealingly connected with the housing. The tubular seal divides the seal chamber into an interior seal chamber which is sealed from an exterior of the housing and an exterior seal chamber which is sealed from an interior space of the housing. At least one seal pressure balancing port is defined by the shaft and extends between the shaft bore and the exterior seal chamber.

Disclosed herein are embodiments of a pressure compensation piston and embodiments of rotary seal assemblies. In one embodiment, a pressure compensation piston for use with a rotary seal assembly includes a stepped piston having an opening extending there through for positioning the stepped piston about a rotatable shaft of a rotary seal assembly. In accordance with this embodiment, the pressure compensation piston further includes a rotary seal positioned along a radial surface of the opening for sealing the stepped piston relative to the rotatable shaft.

A lubrication system for a plunger/packing set of a fluid end has a lubricating fluid reservoir, a pump cooperative with the lubricating fluid reservoir so as to pump a lubricating fluid from the lubricating fluid reservoir toward the plunger/packing set, a primary pressure transducer cooperative with the pump so as to measure a pressure of the lubricating fluid exiting the fluid pump, a secondary pressure transducer cooperative with the fluid end so as to measure a pressure of the lubricating fluid exiting the plunger/packing set, and a controller connected to the second pressure transducer so as to obtain a representation of the pressure measured by the secondary pressure transducer.

The invention relates to a drill drive device (10) for an earth drilling apparatus with a spindle arrangement which has an inner spindle unit (20) and an outer spindle unit (40) that is supported in an axially displaceable manner on the inner spindle unit (20) and floating between two spring means (50, 60). According to the invention provision is made in that a first front spring means (50) which is arranged on a drilling tool side comprises a combination of at least a compression coil spring and a first disk spring arrangement (54) and in that a second rear spring means (60) which faces away from the drilling tool side has a second disk spring arrangement (64).

A downhole tool for use in a downhole drill string is provided. The downhole tool includes a rotor movably coupled within a stator, and a drive shaft movably coupled within a bearing housing. The drive shaft has a first end coupled with the rotor and a second end coupled with a drill bit. Bearing assemblies interfaces engagement between the drive shaft and the bearing housing, including polycrystalline diamond elements, each with an engagement surface, and an opposing engagement surface of a non-superhard metal.