GB641178A - Improvements in or relating to pneumatic conveying systems - Google Patents

Abstract

641,178. Pneumatic conveyers. LANSDOWN, R. F. Sept. 6, 1947, No. 24578. [Class 78 (i)] In a pneumatic conveying system means is provided (1) for maintaining substantially constant the supply pressure of the gas and (2) for controlling the quantity of gas supplied in dependence on variations in the gaseous pressure in the conduit, this latter means being disposed between the gas supply source and the conduit. Material is fed into the conduit 6 from the hopper 2, Fig. 1, by a rotary compartmented member 3 of known construction. Compressed gas supplied to the right-hand end of the conduit passes through valves 8, 9, 10 before reaching the material. The valve 8 is a stop valve and the valve 9 a reducing one. The valve 10 is byepassed by a pipe 13, and is shown in Fig. 2 with the gas passing from left to right. The valve 10 consists of a slidable member 19 provided with an aperture 12, Fig. 3, and is movable in guides 21 in the conduit. It is connected at its upper end to a head 15 acted on by a spring 45 and at its lower end is joined to a piston 25 movable in a cylinder 26. The lower end of the cylinder is connected by a pipe 27 to the conduit at 27a and the upper end to exhaust by the pipe 28. When material is supplied to the conduit, the back pressure rises and the piston is moved up to bring the aperture 12 into the conduit. When the conduit contains a venturi restriction 29, the pipe 27 is connected to the nipple 27b. The valve 19 may be actuated electrically, e.g. by movement of the pointer of a pressure-gauge over contacts to control the energization of a solenoid.