Abstract: A valve assembly for use controlling flow of fluid into a drill pipe, the valve assembly having a valve body, a valve member and a valve seat, wherein a) the valve body has a main passage b) the valve member is movable between a closed position in which the valve member engages with a seat face of the valve seat to substantially prevent flow of fluid along the main passage, and an open position in which the valve member is spaced from the seat face, c) the valve seat is a separate part to the valve body.

Abstract: In some implementations, there is provided an apparatus. The apparatus may include a first steam engine, an intermediate storage, and a second steam engine. The first steam engine may include a first inlet and a first exhaust, wherein the first inlet receives steam from a source of thermal energy. The intermediate storage may be coupled to the first exhaust, wherein the intermediate storage stores thermal energy provided by steam from the first exhaust. The second steam engine may include a second inlet coupled to the intermediate storage. Moreover, at least one of the first steam engine and the second steam engine may produce work. Furthermore, the first steam engine may be driven by the steam received from the source of thermal energy, and the second steam engine may be driven by steam from at least one of the intermediate storage and the first exhaust. Related apparatus and methods are also described.

Abstract: A valve assembly comprising a body having a main passage, and a valve member which is located in the main passage and which is rotatable between an open position in which the main passage is substantially open, and a closed position in which the valve member substantially blocks the main passage, and an actuator which is movable generally parallel to the longitudinal axis of the main passage, the actuator being engaged with the valve member such that movement of the actuator generally parallel to the longitudinal axis of the main passage causes the valve member to rotate between its open and closed positions.

Abstract: A valve assembly for use controlling flow of fluid into a drill pipe, the valve assembly having a valve body, a valve member and a valve seat, wherein a) the valve body has a main passage b) the valve member is movable between a closed position in which the valve member engages with a seat face of the valve seat to substantially prevent flow of fluid along the main passage, and an open position in which the valve member is spaced from the seat face, c) the valve seat is a separate part to the valve body.

Abstract: A valve assembly comprising a body having a main passage, and a valve member which is located in the main passage and which is rotatable between an open position in which the main passage is substantially open, and a closed position in which the valve member substantially blocks the main passage, and an actuator which is movable generally parallel to the longitudinal axis of the main passage, the actuator being engaged with the valve member such that movement of the actuator generally parallel to the longitudinal axis of the main passage causes the valve member to rotate between its open and dosed positions.

Abstract: In some implementations, there is provided an apparatus. The apparatus may include a first steam engine, an intermediate storage, and a second steam engine. The first steam engine may include a first inlet and a first exhaust, wherein the first inlet receives steam from a source of thermal energy. The intermediate storage may be coupled to the first exhaust, wherein the intermediate storage stores thermal energy provided by steam from the first exhaust. The second steam engine may include a second inlet coupled to the intermediate storage. Moreover, at least one of the first steam engine and the second steam engine may produce work. Furthermore, the first steam engine may be driven by the steam received from the source of thermal energy, and the second steam engine may be driven by steam from at least one of the intermediate storage and the first exhaust. Related apparatus and methods are also described.

Abstract: In some implementations, there is provided an apparatus. The apparatus may include a plurality of solar reflectors; a plurality of support rods each coupled to one of the plurality of solar reflectors; a plurality of control plates including a plurality of first openings; a tension plate providing a force to position the plurality of support rods in each of the plurality of first openings; and a driver to move at least one of the plurality of control plates, the movement of the at least one of the plurality of control plates further moving the tension plate, the plurality of support rods, and the plurality of solar reflectors. Related apparatus and methods are also described.