Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.

Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.

Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.

Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.

Abstract: An extended range proportional valve which can control rates of mass flow over continuous low, intermediate and high ranges has a pilot member mounted on an armature of a solenoid which can be dithered onto and off of a pilot opening in a main valve member which seals a main valve opening to control mass flow rates over the low range by varying the duty cycle and/or frequency of a pulse width modulated current in the solenoid coil. Intermediate and high flow rates are achieved by dithering the pilot valve member with a duty cycle and/or frequency sufficient to raise the main valve member relatively short and relatively long respective distances from the main valve seat.

Abstract: A proportional control valve has inlet and outlet solenoids controlling the pressurization and evacuation of a chamber between two pistons in a control valve of the rack and pinion opposed-piston type. The control valve can be maintained in fully open, fully closed, or intermediate positions by selectively energizing and de-energizing the solenoids. The solenoids can be of the normally open or normally closed solenoid poppet types depending on whether the control valve is to open, close or maintain its current state in the event of a power failure.

Abstract: A rocker valve for alternately sealing one of two outlet ports is provided with two cylinders in which there are respectively disposed pistons carrying sealing members for longitudinal reciprocation along the extended axes of valve seats respectively surrounding the port openings. The rocker is rotated to urge one piston toward its respective valve seat while permitting the other piston to be retracted from its respective valve seat. An elastomeric diaphragm is mounted between the sealing members mounted on the pistons and the valve seats whereby the sealing members urge the diaphragm against the valve seats during sealing. The longitudinal motion of the pistons prevents skewing of the sealing members during rotation of the rocker arm for maintaining the sealing members parallel to the valve seats throughout the strokes of the pistons.

Abstract: A digitally controllable valve has a main valve member mounted on a diaphragm for movement sealing and exposing a main valve seat. A flow restriction on the main valve member varies the flow rate as a function of displacement of the main valve member from the main valve seat. Pressure in a reservoir above the diaphragm is controlled by two pilot valves respectively connected to the inlet and outlet ports of the main valve, one of which has fluid passageway with a larger minimum cross sectional area than the other. Both pilots communicate with the reservoir through a single common bleed opening which has an area less than the minimum cross sectional areas of pilot valve flow passageways.

Abstract: A proportional flow valve wherein inlet fluid pressure urges a main valve unit having a main valve member and a surrounding diaphragm toward the valve seat. The diaphragm is connected to the valve body and has a bleed passageway to enable inlet fluid to pass from an inlet port below the main valve unit to a reservoir above it. The area of the main valve unit exposed to the reservoir is substantially greater than the area of the main valve unit exposed to the inlet port. A solenoid actuator determines the position of a pilot valve sealing member which controls the flow of inlet fluid from the reservoir through a pilot opening in the main valve member to an outlet port to selectively relieve the pressure above the main valve unit thereby permitting the main valve unit to move away from the main valve seat.

Abstract: A four-way slide valve including an elongated valve body having an inlet port, an outlet port, and two working ports. A slide assembly within the body is movable longitudinally to alternatively interconnect the outlet port with one or the other of the working ports. The slide assembly carries two longitudinally spaced-apart first and second pistons which define first and second chambers between the pistons and their respective ends of the valve body. Passageways within the slide assembly provide communication between the first chamber and the outlet port, and a control device, such as a pilot valve within the valve body, selectively provides communication between the second chamber and either the inlet port or the outlet port, so as to cause the slide member to move to one of its extreme positions or the other.

Abstract: A self-cycling valve including a main valve and an operator valve. The main valve comprises a body having an inlet port, an exhaust port, and two outlet ports, and valve elements for controlling communication between each outlet port and the inlet and exhaust ports. The operator valve has a valve member movable between two extreme positions for controlling operation of the valve elements of the main valve. In one extreme position of the valve member, one outlet port of the main valve communications with the inlet port and the other outlet port communicates with exhaust; in the other extreme position of the valve member, the outlet port connections are reversed. The valve member of the operator valve cycles between its extreme positions in response to fluid pressure levels at the outlet ports of the main valve.