Abstract: A valve for connecting an external tank to an aircraft has a valve body; and a seal assembly arranged, in use, to resiliently engage a seal surface on an aircraft. The seal assembly has a telescopic seal member extending from a proximal end within the valve body to a distal end. The telescopic seal member is constrained within the valve body so as to maintain axial alignment of the telescopic seal member and the valve body. The seal assembly may also have a seal carrier at the distal end of the telescopic seal member. The seal carrier may be pivotable relative to the telescopic seal member for alignment, in use, with the aircraft seal surface.

Abstract: A method and apparatus for detecting a missing phase in a 3-phase twelve-pulse autotransformer rectifier unit (ATRU) which, in use, receives a 3-phase input and delivers a nominal DC output on which a common-mode voltage is impressed. At least one of the frequency and amplitude of the common-mode voltage are monitored thereby to determine whether there is a missing phase in the input. The frequency and/or amplitude of the common-mode voltage may also be monitored thereby to determine whether there is a loss of input voltage.

Abstract: A fuel supply system for an aircraft is provided for delivering in use fuel from a fuel tank to an aircraft powerplant. The in use fuel flows along a fuel flow passage from the fuel tank to the powerplant. A downstream pump is associated with the powerplant and configured to draw fluid along the fuel flow path so as to supply it to the powerplant in use. An upstream pump is disposed in or associated with the fuel tank and operable to pump fluid along the fuel flow passage. A pressure sensor is configured to monitor a pressure at an inlet to the downstream pump. A fuel system controller is responsive to the pressure sensor and configured to control the upstream pump so as to maintain the pressure at the inlet to the downstream pump at or above a predetermined threshold pressure.

Abstract: An on board inert gas generation system receives cabin air, or air from another relatively low pressure source, passing a portion thereof through an energy recovery turbine to ambient to extract power which is used to provide all, or part of, the energy required to drive a positive displacement compressor to compress another portion of cabin air to increase the pressure thereof to be suitable for supply to an air separation module.

Abstract: A valve actuator having a drive shaft, which, in use, is configured to adjust a valve between an open position and a closed position, an AC induction motor for driving the drive shaft a contactless position sensor configured to, in use, output a signal representing an angular position of the drive shaft or the valve, and a controller configured to control the AC motor in accordance with the signal output by position sensor.

Abstract: A control arrangement for use in a hydraulic control system including a control valve having at least two movable elements, such as spools or poppets, that is adapted to control a main flow through the control valve. The control arrangement further includes a control unit. In an embodiment the control arrangement is adapted to control the operation of the control valve in accordance with a first control scheme, monitor an operating parameter of the control system, and control the operation of the control valve in accordance with a second control scheme in the event that the value of the operating parameter falls outside of a predetermined range.

Abstract: A manual override device for controlling at least one valve in a power system includes a rod having a first end and a second end. An attachment is configured to attach to a spool of the at least one valve and includes a clearance with respect to the first end of the rod so as to allow the attachment to move with the spool, during ordinary operation of the power system, without contacting the rod. A lever is connected to the second end of the rod and is configured to activate the manual override device by moving the rod in a longitudinal direction such that the first end of the rod makes contact with the attachment to move the spool.

Abstract: An on board inert gas generation system for an aircraft receives air from a relatively low pressure source such as low pressure engine bleed air or ram air and passes it to a positive displacement compressor to increase the pressure thereof to be suitable for supply to an air separation module. The speed of the positive displacement compressor may be adjusted across a wide range in order to provide efficient operation in cruise and descent phases of aircraft flight. The operating speed of the compressor and/or the flow rate from the ASM to the space to be inerted may be controlled in accordance with at least one of the gas composition in the space to be inerted, the flight condition, and the ullage volume.

Abstract: An on board inert gas generation system for an aircraft receives air from a relatively low pressure source such as low pressure engine bleed air or ram air and passes it to a positive displacement compressor to increase the pressure thereof to be suitable for supply to an air separation module. The positive displacement compressor comprises a high pressure ratio single stage supercharger with internal cooling.

Abstract: A roller or vane type pump is described of the kind in which the cam ring is pivotally mounted within an external casing to vary the throw of the cam ring and hence the pump delivery means is provided whereby a constant flow is obtained regardless of the pump speed. The cam surface of the cam ring is not wholly circular. The two portions of the cam surface extending between the inlet and outlet ports of the pump at opposite sides respectively of the pump axis have curvatures such that the instantaneous distance R.sub.2 of the point of contact of one of the sealing rollers or vanes with the cam surface from the axis of rotation of the rotor is given by R.sub.2 =.sqroot.R.sub.1.sup.2 +k where k is a constant and R.sub.1 is a corresponding instantaneous distance of the point of contact of the other sealing roller or vane with the cam surface from said axis.

Abstract: The cam surface of a roller-type positive displacement pump providing an inlet port and two outlet ports has on circumferentially opposite sides of at least one of the outlet ports a profile such that the difference between the squares of the radii at the instantaneous points of contact therewith of the two rollers which serve to seal the port at said opposite sides is a constant. The portions of the cam surface at oposite sides of such an outlet port have radii relative to the axis of rotation of the rotor which decrease progressively in the direction of rotation of the rotor.

Abstract: A pumped oil supply system, for example for lubricating an internal combustion engine incorporates a relief valve the control element of which has superimposed thereon an opening force derived from a temperature responsive element responsive to the temperature of the oil delivered by the pump part of the system. The pump part has separate first and second outlets, the second outlet communicating with the oil gallery of the engine and the first outlet communicating with the second outlet through a variable restrictor. The first outlet has a relief valve with a spring-loaded piston acted on by the delivery pressure in the first outlet, and the piston is connected to a center body constituting the adjustable member of the variable restrictor. The temperature responsive element is disposed in the second outlet and imposes a resilient force on the piston which, with increase of the oil temperature, augments the action thereon of the delivery pressure in the first outlet.

Abstract: To minimize the power absorbed by a positive displacement pump system used where the requirement for pressure fluid varies inversely with the pump speed, notably in automobiles, the system provides two separate delivery passages 61, 62 for the pumped fluid and a discharge passage 66 into which the fluid from the delivery passage is passed under the control of a valve means 70, 71, the valve means commencing to operate on one (62) of the two delivered flows at lower speeds to by-pass a proportion of said one flow to an overspill 79, while the fluid not bypassed is added to the flow from the other delivery passage being passed to the discharge passage.

Abstract: A positive displacement pump system has two delivery passages communicating under the control of a valve with a main discharge passage and/or an overspill duct. The valve is constituted by a valve member slidably mounted in a valve bore and the valve member has lands and intermediate recesses controlling communication between the delivery passages and the overspill duct. The pressures upstream and downstream of a discharge orifice in the discharge passage are applied to the valve member in opposition to each other, increase of the pressure drop tending to move the valve member to increase the amount of fluid passed to the overspill duct. To overcome the known tendency for a valve member to be subjected by the hydraulic forces to a large closing force when the valve is open to only a small extent, the valve is designed to provide for a relatively large opening force at least when the valve is commencing to open.

Abstract: A positive displacement pump system has first and second delivery passages for the pumped fluid and a main discharge passage. A control valve operating in dependence on the pressure drop across an orifice in the discharge passage diverts through overspill porting a proportion of the flow through the second delivery passage, the remainder added to the flow from the first delivery passage and passed to the discharge passage. The control valve also regulates the by-passing of a proportion of the flow from the first delivery passage to the overspill porting. As the said pressure drop increases, the control valve first increases the proportion of the flow from the second delivery passage diverted to the overspill porting and, as the pressure drop increases further, then commences to by-pass fluid from the first delivery passage to the overspill port, the quantity by-passed increasing with increase of said pressure drop.

Abstract: A positive displacement pump system provides first and second delivery 11, 12 passages of which the first passage 11 communicates with a main discharge passage 15 containing a discharge orifice 17. The second delivery passage 12 opens to a valve bore and is in permanently open communication with the first delivery passage through an axial passage 29 in a valve member 20 slidably mounted in the valve bore. Lifting of the valve member with increasing pressure drop across the orifice 17 places the first delivery passage in communication with an overspill port 14. The pressure at the upstream and downstream sides of the orifice are applied against the lower end and the upper end 28 of the valve member so that the valve operates to maintain the pressure difference constant. The pressure difference between passage 29 and that applied against the upper end 28 of the valve member is therefore also substantially constant, so that leakage from passage 29 past the upper end 28 is constant.