Abstract: A method and apparatus according to which an output of a power generation system is controlled. In one embodiment, the power generation system includes a turbine and a feedback control system. The turbine includes a rotor to which a first portion of a power fluid is communicated, the first portion imparting torque to the rotor; a shaft to which the rotor is connected; a shroud extending circumferentially about the rotor and the shaft; and a bypass gap between the rotor and the shroud, through which a second portion of the power fluid is communicated. The feedback control system axially displaces the shroud relative to the rotor, thereby adjusting the size of the bypass gap and, consequently, the ratio of the first portion relative to the second portion.

Abstract: A method and apparatus according to which an output of a power generation system is controlled. In one embodiment, the power generation system includes a turbine and a feedback control system. The turbine includes a rotor to which a first portion of a power fluid is communicated, the first portion imparting torque to the rotor; a shaft to which the rotor is connected; a shroud extending circumferentially about the rotor and the shaft; and a bypass gap between the rotor and the shroud, through which a second portion of the power fluid is communicated. The feedback control system axially displaces the shroud relative to the rotor, thereby adjusting the size of the bypass gap and, consequently, the ratio of the first portion relative to the second portion.

Abstract: A downhole tool includes a temperature sensitive component. The temperature of the temperature sensitive component is at least partially controlled by a temperature management system thermally coupled to the temperature sensitive component. The temperature management system may include a cold plate thermally coupled to the temperature sensitive component, a hot plate thermally coupled to the cold plate, and a thermo-electrical converter system thermally coupled to the hot plate and to the body of the downhole tool, wherein the thermo-electrical converter system comprises two membrane electrode assemblies.

Abstract: A downhole tool includes a temperature sensitive component. The temperature of the temperature sensitive component is at least partially controlled by a temperature management system thermally coupled to the temperature sensitive component. The temperature management system may include a cooling mixture chamber thermally coupled to the temperature sensitive component, wherein first and second components of a cooling mixture cause an endothermic reaction when mixed together within the cooling mixture chamber.

Abstract: A downhole tool includes a temperature sensitive component. The temperature of the temperature sensitive component is at least partially controlled by a temperature management system thermally coupled to the temperature sensitive component. A metal hydride may be selectively thermally coupled to a cold plate that is thermally coupled to the temperature sensitive component.

Abstract: A downhole sensor calibration apparatus includes a rotational or gimbaling mechanism for guiding a sensing axis of an orientation responsive sensor through a three-dimensional orbit about three orthogonal axes. A method includes using measurements taken over the three-dimensional orbit to calibrate the sensor and determine other characteristics of the sensor or tool.

Abstract: A downhole tool includes a temperature sensitive component. The temperature of the temperature sensitive component is at least partially controlled by a temperature management system thermally coupled to the temperature sensitive component. A metal hydride may be selectively thermally coupled to a cold plate that is thermally coupled to the temperature sensitive component.

Abstract: A downhole tool includes a temperature sensitive component. The temperature of the temperature sensitive component is at least partially controlled by a temperature management system thermally coupled to the temperature sensitive component. The temperature management system may include a cold plate thermally coupled to the temperature sensitive component, a hot plate thermally coupled to the cold plate, and a thermo-electrical converter system thermally coupled to the hot plate and to the body of the downhole tool, wherein the thermo-electrical converter system comprises two membrane electrode assemblies.

Abstract: A downhole tool includes a temperature sensitive component. The temperature of the temperature sensitive component is at least partially controlled by a temperature management system thermally coupled to the temperature sensitive component. The temperature management system may include a cooling mixture chamber thermally coupled to the temperature sensitive component, wherein first and second components of a cooling mixture cause an endothermic reaction when mixed together within the cooling mixture chamber.

Abstract: A downhole tool includes a thermally sensitive component. The temperature of the thermally sensitive component is at least partially controlled by a temperature management system thermally coupled to the thermally sensitive component.

Abstract: A downhole sensor calibration apparatus includes a rotational or gimbaling mechanism for guiding a sensing axis of an orientation responsive sensor through a three-dimensional orbit about three orthogonal axes. A method includes using measurements taken over the three-dimensional orbit to calibrate the sensor and determine other characteristics of the sensor or tool.

Abstract: A downhole sensor calibration apparatus includes a rotational or gimbaling mechanism for guiding a sensing axis of an orientation responsive sensor through a three-dimensional orbit about three orthogonal axes. A method includes using measurements taken over the three-dimensional orbit to calibrate the sensor and determine other characteristics of the sensor or tool.

Abstract: A downhole sensor calibration apparatus includes a rotational or gimbaling mechanism for guiding a sensing axis of an orientation responsive sensor through a three-dimensional orbit about three orthogonal axes. A method includes using measurements taken over the three-dimensional orbit to calibrate the sensor and determine other characteristics of the sensor or tool.

Abstract: A downhole tool includes a thermally sensitive component. The temperature of the thermally sensitive component is at least partially controlled by a temperature management system thermally coupled to the thermally sensitive component.

Abstract: A downhole tool for use in a wellbore, comprises a tubular member, such as a drill collar housing, in a drill string. The tubular member has at least one cavity formed on an external surface. At least one housing is adapted to be insertable and extractable in the cavity without further tool disassembly. The housing has at least one electrical device such as a battery stack disposed within. In another aspect, sensors are disposed in the housing for measuring downhole parameters of interest including, but not limited to, annulus pressure and annulus temperature. A method of replacing an electrical device in a downhole tool, comprises removing a first housing containing the electrical device from a cavity on an external surface of the downhole tool, and installing a second housing containing a second electrical device in the cavity without disassembling the tool further.

Abstract: A downhole tool for use in a wellbore, comprises a tubular member, such as a drill collar housing, in a drill string. The tubular member has at least one cavity formed on an external surface. At least one housing is adapted to be insertable and extractable in the cavity without further tool disassembly. The housing has at least one electrical device such as a battery stack disposed within. In another aspect, sensors are disposed in the housing for measuring downhole parameters of interest including, but not limited to, annulus pressure and annulus temperature. A method of replacing an electrical device in a downhole tool, comprises removing a first housing containing the electrical device from a cavity on an external surface of the downhole tool, and installing a second housing containing a second electrical device in the cavity without disassembling the tool further.