A proportional air flow control valve, which is used for controlling fluid flow through a flexible tube, includes first and second jaws on opposing sides of the tube. A valve actuator drives one of such jaws for adjusting the separation distance there between. 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 a 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. A control circuit responsive to the light sensor regulates the flow rate of the control valve.
The functional part of the proportional air flow control valve allows an infinitely variable setting of the flow of gaseous or liquid fluids. Flow orifice cross section is adjusted according to the electric (voltage or current) input command signal. The input command signal is typically derived from a potentiometer or process controller. An external amplifier is required to convert the input command signal into a proportional solenoid current to control the valve.
A Proportional air flow control valve can have several applications. A proportional air flow control valve can considerably improve the controlled supply of fluids such as air, neutral gasses and light oil. Water applications of a proportional air flow control valve are not recommended due to the potential for dissolved mineral deposit build-up in the solenoid plunger area. It is important to take note that a proportional air flow control valve is not intended to be used as a tight shut-off valve.
The construction of the proportional air flow control valve is a poppet type flow control valve, and it is direct acting. It is a protection class with an IP65 connector installed. A vertical mounting position for the proportional air flow control valve is preferred. The preferred flow direction of the proportional air flow control valve is vertical. The proportional air flow control valve can handle fluids such as air, neutral gasses or light oil and the fluid temperatures can be from 15 to 120 degrees Fahrenheit.
It is recommended that a 30 micron filter be installed upstream of the proportional air flow control valve at all times. The materials used in the construction of the proportional air flow control valve are brass for the housing, and the internal parts are brass and stainless steel. The seals are made from Teflon. The flow factor of a proportional air flow control valve is CV = 1.3. The weight of a Proportional air flow control valve is 4.0 lb.
