Pneumatic outlet control valve

摘要

In accordance with the present invention, in a pneumatic outlet a discharge tube is attached to sloped outlet walls having lips at their lower inner edges. A rotatable control valve is located within the discharge tube. The control valve is provided with a pattern of openings for metering flow of lading into the discharge tube and is arranged to reduce or eliminate pellets from becoming trapped in the valve opening. Preferably the metering contour includes a pattern of sharp edges and tapered recesses. The tapered recesses are arranged to guide pellets away from the valve opening. The sharp edges will shear the remaining pellets which are trapped in the metering opening, thus avoiding jamming the control tube. The control valve further comprises arcuate segment of less than 180 DEG . With this arcuate segment any pellets trapped between the control valve and the wall of the tube tend to bend the control valve away from the lips and thus reduce any tendency for the control valve to become bound and unrotatable because the control valve abuts one of the lips.