Abstract: A valve (11) for controlling the flow of a drilling fluid through a down-hole tool (10) positionable in a wellbore penetrating a subterranean formation. The down-hole tool has a housing with a drilling motor therein and a drill bit (1) at an end thereof. The drilling motor (9) has a housing with a rotor (206) rotationally movable in a rotor channel (204) as the drilling fluid passes through a rotor channel between the housing and the rotor. The rotor has a bypass channel therethrough for bypassing a portion of the drilling fluid therethrough. The valve includes a valve plate positionable upstream of the motor. The valve plate (200) has at least one flow passage (226) and at least one bypass passage (220) therethrough. The flow passage is in fluid communication with the rotor channel for passing the drilling fluid therethrough.

Abstract: a seal comprises a metal seal ring with a first slanted mating surface for sealing engagement with a mating surface on a body and a second slanted mating surface for sealing engagement with a mating surface on a bonnet. The mating surfaces are the same angle as measured from the axis of the ram of the BOP. The seal also defines opposing slanting surfaces which provide a degree of flexure to the seal for sealing engagement. With the application of pressure on the inside surfaces of the seal, the mating surfaces are pressed even harder against the mating surfaces of the body and bonnet.

Abstract: An improved alternating current prime mover control system and method for, for example, the control of a valve position or other physical variable whose state can be sensed or calculated wherein the state of the physical variable is compared with a reference variable to generate, in conjunction with a waveform generator, a fixed amplitude signal that has variable time duration which feeds a part of the control system that drives the alternating current prime mover source in more than one direction.

Abstract: An improved alternating current prime mover control system and method for, for example, the control of a valve position or other physical variable whose state can be sensed or calculated wherein the state of the physical variable is compared with a reference variable to generate, in conjunction with a waveform generator, a fixed amplitude signal that has variable time duration which feeds a part of the control system that drives the alternating current prime mover source in more than one direction.