Abstract: A test stand having a control chamber with a fluid pressure therein for simulating an operational parameter of a device. A doser system with a controller which receives an input representing a desired pressure Px in the control chamber. The controller supplies either a first or second solenoid valve with an actuation signal to allow fluid pressure from a source to enter the control chamber or fluid from the control chamber to flow to the surrounding environment to change the fluid pressure in the control chamber form Pc to Pc'. A pressure transducer supplies the controller with a feedback signal corresponding to the actual fluid pressure Pc' in the control chamber. The controller derives an error signal (Px-Pc') to define an update for the actuation signal. As Pc' approaches Px, the duration of the actuation signal correspondingly changes to assure that the desired fluid pressure for the control chamber is achieved without exceeding the desired fluid pressure in a relatively short time period.

Abstract: The invention is a control system for generating time modulated pulse signals to effect movement of a doser type actuator. The control system is characterized in that it includes an augmenter circuit which generates a first correction signal additive to scheduled control signals when the actuator fails to respond or has a response below a predetermined limit to an actuating pulse, a second correction circuit which generates a correction signal proportional to the magnitude of the first movement of the actuator response to a pulse signal for reducing the magnitude of the pulse signal in proportion to the magnitude of the movement, and a gating signal or circuit which blocks said first and second correction signal generating circuits generating the augmentation signal when the movement of the actuator in response to a pulse signal is negative or above a predetermined limit, when the positional error changes direction, or when the actuator position is within the desired deadband limits.

Abstract: A control system (10) for supplying an operational chamber (38) in an air motor with pressurized fluid causing rotors (18 and 20) therein to move and develop an output torque in response to an input signal. Electrically operated valves (52 and 54) selectively controlling the flow of fluid from first and second bellows means (48 and 50) which are normally seated to seal distribution conduit (34 and 36) connecting the operational chamber (38) to the atmosphere. A select high disc valve (104) in the fluid pressure supply passage provides operating fluid to the distribution conduit (34 or 36) opposite the one which is vented to the atmosphere. In a two position air motor powered actuator, the electrical signals for the valves (52 and 54) may be derived as a simple function of actual rotor rotation and rotor rotational speed.

Abstract: A metering valve (20) for supplying a turbine engine with a fuel at a substantially constant flow rate in response to operational conditions evaluated by a computer (28). A signal from the computer (28) in the form of voltage pulses is supplied to a solenoid (30). The solenoid (30) regulates the flow of fuel from a control chamber (54) to produce a fuel pressure P.sub.x therein. The fuel enters a supply chamber (46) and the fuel pressure P.sub.1 thereof acts on the effective area of a first diaphragm (42) to move face (70) on plunger (68) away from seat (38) in opposition to a closing force generated by the fluid pressure P.sub.x acting on a second diaphragm (48). A feedback valve (90) regulates the flow of fuel from supply chamber (46) to control chamber (54). By making the size of the first diaphragm (42) one half the size of the second diaphragm (48) when P.sub.x is equal to one half of the sum of fuel pressures P.sub.1 and P.sub.

Abstract: In a turbine engine (8) having a shaft (60) with turbine blades (24, 24', . . . 24.sup.N) thereon which rotate in a chamber (12) of the engine housing (10) to produce thrust in response to an operator input. A pneumatic sensor system (30) connected to said housing (10) for maintaining the space relationship between the tip (26, 26', . . . 26.sup.N) of the blades (24, 24', . . . 24.sup.N) and the wall (28) of housing 10 within set limits under varying operational conditions experienced by the turbine engine (8).

Abstract: In an actuator system (10) having an air motor (12) for supplying a ball-screw actuator (14) with rotary input. The ball screw actuator (12) has a friction clutch mechanism (206) that limits the torque applied to the screw (176) when the ball nut (166) reaches first and second extreme positions. Thus, the maximum output from the air motor (12) can be applied to ball screw actuator (14) without braking before the positions are reached. A torsion bar and a cam 274 act to regulate the clutch (206) slipping torque to narrow limits, thereby easing strength requirements in the actuation mechanism (10).

Abstract: A control system 54 for a doser type hydraulic actuator 56 is disclosed. The doser actuator includes a pair of unequal area pistons 18, 20 on a common shaft 16 which are moved incrementally by injecting into or removing from a control pressure chamber metered quantities or doses of fluid. The doses are metered by timed openings of solenoid valves 32, 34 connecting the control pressure chambered to a supply 44 or return 48 pressure sources. The control system includes a base pulse width signal generator 106 which pulse modulates the solenoids as a function of the error between a requested position and an actual position. The base pulse width is modified by a correction means 108, 110, 112 when the error is within a predetermined band width. The correcting means compensates for the reaction of the actuator when its response is uncertain with respect to the base pulse width.

Abstract: A valve arrangement responsive to a pressure differential continuously throttles air flowing through a labyrinth seal, allowing only a small fraction of the leakage that would otherwise occur. The arrangement accomodates radial and axial shaft displacement without rubbing contact. This avoids seal wear for high shaft rotating speeds, high temperatures and/or rapid temperature changes.

Abstract: A system for cooling the bearings supporting the shaft of a rotor in a pneumatic motor powered with hot pressurized fluid. The rotor responds to the flow of hot fluid under pressure by moving to develop output power. The rotors which conduct heat from the hot fluid through the shaft and into the bearings have a series of peripheral axial slots adjacent the ends of the shaft. Fasteners engage the shaft to position the bearings over the series of axial slots. A manifold connects the slots to a discharge conduit. Some of the hot pressurized fluid is diverted through a nozzle in the discharge conduit to create a pressure differential between the manifold and the surrounding environment. This pressure differential draws air from the surrounding environment through the slots and into the manifold. The air on flowing through the slots absorbs heat from the shaft and the inside of the bearings to thereafter maintain the temperature of the bearing below the hot fluid.

Abstract: A doser type hydraulic actuator includes a pair of unequal area pistons on a common shaft which are moved incrementally by injecting into or removing from a control pressure chamber metered quantities or doses of fluid. Doses are metered by timed openings of solenoid valves connecting the control pressure chamber to supply or return pressure sources. Special valve means are provided for moving the actuator piston to a preferred position in the event of control system failure, and means are included for administering very small doses consistently without recourse to special extra fast response solenoid valves.

Abstract: A variable flow ejector for use in controlling the amount of bypass flow in a fluid delivery system which includes a pump, a metering orifice and a bypass line for circulating a variable amount of flow from the pump outlet to the pump inlet to control the pressure drop across the orifice. The bypass flow enters the ejector through a variable area nozzle coaxially disposed with respect to a stream from a source of fluid whereby the velocity head of the bypass flow is recovered as pressure head at the pump inlet for increased efficiency. The bypass flow is controlled by varying the area of the ejector nozzle as a combined function proportional to the pressure drop across the orifice plus the time integral of the error in the pressure drop across the orifice.

Abstract: A rotary stepper actuator having a rotatable output shaft provided with a cam portion fixedly secured thereto and engaged by a plurality of pairs of oppositely acting fluid pressure responsive pistons wherein each pair of pistons is movable along an axis intersecting the axis of the shaft. Preferably, the pistons are arranged in circumferentially spaced apart formation around the shaft and provided with roller elements adapted to bear against the cam portion the periphery of which takes the general form of an ellipse having opposite depressed mid portions. The applied piston forces acting through the rollers against the peripheral edge of the crank portion produce a force couple tending to rotate the shaft to the extent that the rollers become engaged with the opposite depressed mid portions whereupon the couple becomes reversed preventing further rotation of the shaft.