Camco International, Inc.

Stewart & Stevenson Services, Inc.

Randall R Price

Robert A Baten

Bruce A Vicknair

Michael P Dearing

Greg L Cedillo

John Howard Craig

Walter Scott Dillard

Clifford Stanley Montgomery

The present invention is a low differential pressure relief valve made up of a valve body and an elastic membrane for downhole tools, especially rolling cutter drill bits. An aperture is formed in the membrane and a valve body with protruding end stops is mounted in the aperture. The thickness and shape of the valve body are such that the aperture is stretched when assembled. The amount the membrane is stretched and the geometry of the protruding end stop, control the differential relief pressure. The valve body and each end stop can be designed so that the pressure relief setting will be different, depending upon which side of the membrane has the higher pressure. The relief device may be adapted to be integral with existing elastic membrane type lubricant pressure compensation devices for downhole tools.

Rock bit lubricant relief valve

A novel split threaded ring bearing member for rolling cutter drill bits with at least a portion of its threads having a different pitch than its mating threads is disclosed. The pitch difference is designed so that the threaded ring can be seated or otherwise located precisely with respect to the other bearing elements within the drill bit to effectively control the axial displacement of the rolling cutter on the bearing spindle within a given tolerance range. Upon assembly, the difference in thread pitch causes the opposite, opposing mating thread flanks to engage, effectively applying a tensile or compressive force to a portion of the threaded ring bearing member, which gradually increases as the assembly is tightened. The result is an improved rolling cutter drill bit with a threaded ring cutter bearing system with excellent resistance to back-off which will not allow significant radial movement between the engaged threads, even if some back-off of the threads occurs.

Rock bit cutter retainer with differentially pitched threads

An automatic cementing system and method are disclosed for precisely controlling the density of a slurry during a continuously mixed cement application. The system includes an input water line and a dry cement hopper for supplying water and cement, respectively, to a mixing chamber. The mixing chamber includes two chambers, Chamber A and Chamber B, for thoroughly mixing the water and cement together to form a cement slurry. Chamber B includes a level sensor for measuring the change in slurry level. The input line includes a pump for supplying the water to the mixing chamber, and a flow meter for measuring the rate at which the water is supplied. Similarly, the hopper includes a slide-gate valve for regulating the rate at which the dry cement is supplied to the mixing chamber. A discharge line with a discharge pump and a discharge flow meter receives and discharges cement slurry. A recirculation line is included for density control during initialization. A system controller receives operational parameters from the operator, including desired slurry density, mix water density, and dry cement density. As the slurry discharge rate increases to the desired value, the mix water flow rate increases to maintain the calculated volume percentage of mix water in the discharge slurry constant. The tub level drops, causing the slide-gate valve to open and add cement, raising the tub level to the setpoint level and maintaining an accurate discharge slurry density.

Automatic cementing system with improved density control

An automatic cementing system and method are disclosed for precisely controlling the density of a slurry during a continuously mixed cement application. The system includes an input water line and a dry cement hopper for supplying water and dry cement, respectively, to a mixing chamber. The mixing chamber includes two chambers, Chamber A and Chamber B, for thoroughly mixing the water and cement together to form a cement slurry. Chamber B includes a level sensor for measuring the change in slurry level. The input line includes a pump for supplying the water to the mixing chamber, and a flow meter for measuring the rate at which the water is supplied. Similarly, the hopper includes a rotary valve for regulating the rate at which the dry cement is supplied to the mixing chamber and a speed sensor for measuring the speed of the rotary valve. A discharge line with a discharge pump and a discharge flow meter receives and discharges cement slurry. A recirculation line is included for density control during initialization. A system controller receives operational parameters from the operator, including desired slurry density, mix water density and dry cement density. Once the rate of the input pump is set, the controller monitors the output from the level sensor in Chamber B and adjusts the rotary valve until the level of slurry in Chamber B is constant. At that time, the amount of water leaving the system as slurry is calculated by the controller, and the controller then sets the rate of the input pump based upon this calculation.

Growing community of inventors

Houston, TX, United States of America

Randall R Price