1
Jim B Surjaatmadja, James C Tucker: Slow rotating tool with gear reducer. Halliburton Energy Services, Robert Kent, Anthony L Rahhal, January 8, 2002: US06336502 (63 worldwide citation)

A slow rotating apparatus for use in performing downhole operations. The apparatus generally consists of a motor section with a rotor rotatable in response to fluid flow, a speed reducer section connected to the motor section such that an output speed of the speed reducer section is less than an out ...


2
John Forrest: Composite stator construction for downhole drilling motors. Drilex Systems, Edgar A Zarins, Malcolm L Sutherland, December 15, 1992: US05171138 (53 worldwide citation)

A composite stator construction for a downhole drilling motor which provides improved sealing and distortion properties. The elastomer which maintains the sealing/pumping action of the motor is applied in a uniform thickness to a rigid metallic form. In the stator, the rigid former has the basic con ...


3
David A Murphy, Peter C Spellar: Micro-processor control of compression ratio at full load in a helical screw rotary compressor responsive to compressor drive motor current. Frick Company, Dowell & Dowell, October 22, 1985: US04548549 (51 worldwide citation)

A method of operating an electric drive motor for an axial flow helical screw type compressor having a slide valve member and slide stop member mounted beneath the intermeshing rotors such that the slide member controls communication between the work chamber defined by the rotors and the casing to t ...


4
Darrell L Sims, Kirk R Shirley: Progressive cavity drive train. A Z International Tool Company, Vinson & Elkins, March 21, 1978: US04080115 (51 worldwide citation)

An improved drive train for a progressive cavity device is disclosed. The progressive cavity device has a rotor, a stator, means for fluid to enter between said stator and rotor, and means for fluid to exit therefrom. The rotor is adapted to roll with respect to the stator. The improved drive train ...


5
Russell D Ide: Hermetically sealed progressive cavity drive train for use in downhole drilling. Marks Murase & White, September 17, 1991: US05048622 (31 worldwide citation)

A drilling apparatus having progressive cavity drive train which includes a progressive cavity device and a coupling for converting the complex motion of the rotor into simple rotation. The coupling includes a sealed universal joint assembly coupling yokes formed on a first stub shaft to yokes forme ...


6
Donald M Haarstad: Steering control unit with flow amplification. Eaton Corporation, L J Kasper, July 26, 1988: US04759182 (31 worldwide citation)

A fluid controller (17) is disclosed for controlling the flow of fluid to a steering cylinder (19). The controller includes a fluid meter (51) and a valving arrangement (49) including a valve spool (65) and a sleeve (67), which define a main fluid path including a main variable flow control orifice ...


7
Shen Peiji: Cycloidal equidistant curved gear transmission mechanism and its device. Pennie & Edmonds, May 8, 1990: US04922781 (30 worldwide citation)

This invention involves a gear transmission mechanism and its device which incorporate double cycloidal equidistant conjugated gear mechanisms and devices, featuring in that a whole branch cyclic cycloidal equidistant curve at a side of the center of curvature of that cycloid is applied with the val ...


8
Robert C Tucker Jr, Melvin D Mendenhall, Madapusi K Keshavan: Carbide or boride coated rotor for a positive displacement motor or pump. Praxair S T Technology, Cornelius F O Brien, March 7, 1995: US05395221 (29 worldwide citation)

A rotor for a positive displacement motor or pump in which the rotor is coated with a metal carbide and metal alloy coating or a metal boride and metal alloy coating to impart excellent wear-resistance and corrosion-resistance properties to the rotor when used in abrasive and/or corrosion resistance ...


9
Steven M Wood, Brian E Spencer: Progressive cavity motors using composite materials. Steven M Wood, Head Johnson & Kachigian, February 6, 2001: US06183226 (27 worldwide citation)

The stator, rotor and/or flex shaft of a progressive cavity motor is made up of composite materials, e.g., fiberglass and resin, in a variety of combinations with and without bonded resilient elastomers. The composites are formulated to provide resiliency and non-resiliency where needed. The flex sh ...


10
John E Tschirky: Progressive cavity transducer. Smith International, Subkow and Kriegel, December 28, 1976: US03999901 (26 worldwide citation)

This invention relates to progressing cavity fluid motors with multiple stator elements connected in series to provide a fluid passageway from the input of the initial stator of the series to the output of the terminal stator of the series; the rotor elements in each stator are connected together fo ...