Abstract: A filter is disclosed. The filter includes a sheet of filter media defining a body having an upper portion, a lower portion, a first end surface proximate the upper portion, a second end surface proximate the lower portion, and a first side surface extending between the first and second end surfaces. One or more of the upper and lower portions define a ledge, wherein the ledge defines a third end surface arranged between the first and second end surfaces, and a second side surface extending between the first and third end surfaces; and a seal disposed upon the ledge. A method for manufacturing the seal is also disclosed.

Abstract: A self-snubbing hydraulic actuation system includes a hydraulic motor, a component actuator, a control valve, a valve actuator, and a variable resistance device. The hydraulic motor is configured, upon receipt of hydraulic fluid, to rotate and supply a drive torque. The component actuator is configured, upon receipt of drive torque from the motor, to translate to a position. The control valve is movable to a plurality of valve positions to thereby control hydraulic fluid flow rate to the hydraulic motor. The valve actuator is coupled to the control valve and is adapted to receive electrical current and to move the control valve to a valve position based on the magnitude of the received electrical current. The variable resistance device is configured, based on component actuator position, to selectively vary the magnitude of the electrical current received by the valve actuator.

Abstract: A self-snubbing hydraulic actuation system includes a hydraulic motor, a component actuator, a control valve, a valve actuator, and a variable resistance device. The hydraulic motor is configured, upon receipt of hydraulic fluid, to rotate and supply a drive torque. The component actuator is configured, upon receipt of drive torque from the motor, to translate to a position. The control valve is movable to a plurality of valve positions to thereby control hydraulic fluid flow rate to the hydraulic motor. The valve actuator is coupled to the control valve and is adapted to receive electrical current and to move the control valve to a valve position based on the magnitude of the received electrical current. The variable resistance device is configured, based on component actuator position, to selectively vary the magnitude of the electrical current received by the valve actuator.

Abstract: Systems and methods of controlling solid propellant gas pressure and vehicle thrust are provided. Propellant gas pressure and a vehicle inertial characteristic are sensed. Propellant gas pressure commands and vehicle thrust commands are generated. A propellant gas pressure error is determined based on the propellant gas pressure commands and the sensed propellant gas pressure, and vehicle thrust error is determined based on the vehicle thrust commands and the sensed vehicle inertial characteristic. Reaction control valves are moved between closed and full-open positions based on the determined propellant gas pressure error and on the determined vehicle thrust error. The system and method allow the reaction control valves to operate at variable frequencies or at fixed frequencies. The system and method also allows propellant pressure to be commanded to follow a predetermined pressure profile or commanded to vary “on-the-fly.

Abstract: Systems and methods of controlling solid propellant burn rate, propellant gas pressure, propellant gas pressure pulse shape, and propellant gas flow rate, rely on pulse width modulation of a control valve duty cycle. A control valve that is movable between a closed position and a full-open position is disposed downstream of, and in fluid communication with, a solid propellant gas generator. The solid propellant in the solid propellant gas generator is ignited, to thereby generate propellant gas. The control valve is moved between the closed position and the full-open position at an operating frequency and with a valve duty cycle. The valve duty cycle is the ratio of a time the control valve is in the full-open position to a time it takes the valve to complete one movement cycle at the operating frequency. The valve duty cycle is controlled to attain a desired solid propellant burn rate, propellant gas pressure, propellant gas pressure pulse shape, and/or propellant gas flow rate.

Abstract: Systems and methods of controlling solid propellant gas pressure and vehicle thrust are provided. Propellant gas pressure and a vehicle inertial characteristic are sensed. Propellant gas pressure commands and vehicle thrust commands are generated. A propellant gas pressure error is determined based on the propellant gas pressure commands and the sensed propellant gas pressure, and vehicle thrust error is determined based on the vehicle thrust commands and the sensed vehicle inertial characteristic. Reaction control valves are moved between closed and full-open positions based on the determined propellant gas pressure error and on the determined vehicle thrust error. The system and method allow the reaction control valves to operate at variable frequencies or at fixed frequencies. The system and method also allows propellant pressure to be commanded to follow a predetermined pressure profile or commanded to vary “on-the-fly.

Abstract: Systems and methods of controlling solid propellant burn rate, propellant gas pressure, propellant gas pressure pulse shape, and propellant gas flow rate, rely on pulse width modulation of a control valve duty cycle. A control valve that is movable between a closed position and a full-open position is disposed downstream of, and in fluid communication with, a solid propellant gas generator. The solid propellant in the solid propellant gas generator is ignited, to thereby generate propellant gas. The control valve is moved between the closed position and the full-open position at an operating frequency and with a valve duty cycle. The valve duty cycle is the ratio of a time the control valve is in the full-open position to a time it takes the valve to complete one movement cycle at the operating frequency. The valve duty cycle is controlled to attain a desired solid propellant burn rate, propellant gas pressure, propellant gas pressure pulse shape, and/or propellant gas flow rate.

Abstract: A valve comprises a valve body, a poppet, and a pin. The valve body includes an inlet, an outlet, and a fluid flow passage therebetween. The poppet is disposed in the valve body, and is moveable between a closed position, in which the poppet at least substantially restricts fluid from flowing through the fluid flow passage, and an open position, in which fluid is allowed to flow through the fluid flow passage. The pin is disposed in the valve body, and extends at least partially into the poppet. The pin is configured to guide poppet movement in the valve body between the closed position and the open position. In this configuration, the ratio of the poppet length to diameter can be less than one.

Abstract: A vehicle, such as a missile, with a pilot valve system controls the vehicle's thrust valves despite a hostile propellant gas environment. The pilot valve system can have one or more pilot valves. Using refractory elements, the pilot valve ball reciprocates between a supply seat and a vent seat which is subject to the filtered inflow of propellant thrust gases. When open, the pilot valve allows the stray thrust gas to communicate to a control chamber which closes a poppet against a valve seat in the nozzle. When an associated solenoid closes the pilot valve by pushing the pilot valve ball against the supply seat, the control chamber is vented to ambient. The poppet may then travel into the cylinder bore and the nozzle is opened to exhaust propellant gases and exert lateral thrust on the vehicle. Certain nozzle thrust geometries provide useful vehicle guidance.

Abstract: A vehicle, such as a missile, with a pilot valve system controls the vehicle's thrust valves despite a hostile propellant gas environment. The pilot valve system can have one or more pilot valves. Using refractory elements, the pilot valve ball reciprocates between a supply seat and a vent seat which is subject to the filtered inflow of propellant thrust gases. When open, the pilot valve allows the stray thrust gas to communicate to a control chamber which closes a poppet against a valve seat in the nozzle. When an associated solenoid closes the pilot valve by pushing the pilot valve ball against the supply seat, the control chamber is vented to ambient. The poppet may then travel into the cylinder bore and the nozzle is opened to exhaust propellant gases and exert lateral thrust on the vehicle. Certain nozzle thrust geometries provide useful vehicle guidance.

Abstract: In accordance with the present invention, a method for forming solder bumps begins with a wafer that has been patterned with bond pad areas. A plurality of distinct metal layers are then deposited over the wafer. Subsequently, solder is deposited by way of plating through a mask over the metal layers in the bond pad areas. After the removal of the mask, the metal layers outside of the soldered areas are etched using a dilute phosphoric acid solution, which includes phosphoric acid, acetic acid, hydrogen peroxide, and deionized water. By the use of this solution, the metal layers are removed without attacking the soldered areas. Thus, a pattern of solder bumps are formed. The metal layers include distinct layers of aluminum, nickel-vanadium, and copper. Alternatively, the aluminum layer is eliminated.