Abstract: A proportional flow control valve, for controlling fluid flow through a flexible tube, includes first and second jaws on opposing sides of the tube. An actuator drives one of such jaws for adjusting the separation distance therebetween. When the valve is open, the separation distance is small enough to partially deform the tube without significantly restricting fluid flow. When the valve is closed, the separation distance is just small enough to essentially block fluid flow. A control system controls the actuator to determine such separation distance. Such valve can be used within a level control system for controlling the thickness of a work material in a slurry form cast upon a moving belt. A fluid reservoir is disposed above the belt, and the control valve adds slurry to the reservoir. A lens disposed near the moving belt and above the reservoir is coupled by fiber optics to a remote sensor for detecting the height of the slurry.

Abstract: A position controller including a position transmitter (9) and a control unit (13). The position transmitter detects the actual position of an actuator (7). The control unit (13) is arranged in an ignition-proof enclosure that is separate from the housing of the position transmitter (9). The interface (18) between the control unit (13) and the position transmitter (9) as well as the position transmitter (9) itself—which comprises a magnet (10) and a magnetoresistive sensor (50)—have an inherent electrical safety design.

Abstract: An electronic control circuit for controlling an electromagnetic valve having an armature, in particular for a heating and/or air-conditioning system in a motor vehicle, has an electronic switching element in series with the coil of the valve and is characterized in that the switching element controls the valve voltage (or the valve current) applied to the coil so that the valve voltage reaches a first value when the valve is switched on; then the valve voltage is reduced to a second value which is lower than the first value; and thereafter the valve voltage assumes a third value which is greater than the second value and represents a holding voltage for holding the armature in its switched-on position.

Abstract: In a main valve having a solenoid pilot operated valve, a movable core and a hollow plunger are movably received in a sleeve extending from a pressure control chamber through an electromagnetic coil. The plunger is structurally separated from a main valve member. A shaft is slidably received in the plunger. One end of the shaft carries a pilot valve member. A spring engages at the plunger and the shaft such that the free end of the shaft projects a predetermined length beyond an end face of the plunger. As long as the coil is deenergized, the spring separates the pilot valve member from a pilot valve seat. As soon as the coil is energized, the plunger is attracted to the core, the shaft is displaced in relation to the plunger, and the pilot valve member projecting from the lower end of the plunger closes the pilot valve seat. Due to the developing pressure difference, the main valve is closed and kept in a closed state.

Abstract: The objection of the present invention is to provide an actuator possible to transmit an output from a power rod of the actuator as rotary motion, and to provide an exhaust brake unit using the actuator, easy to assemble, a small space necessary for installation, able to place the actuator in such a manner that an axis of a power rod of the actuator and an axis of a valve shaft are aligned in a line, and heat transfer from an exhaust channel to the actuator is minimized.