GB191313693A - Improvements in the Valve Gear of Steam Driven Pumps. - Google Patents

Abstract

13,693. Little, J. June 13. Combined fluid - actuated and mechanical gears. - Steam is distributed to the power cylinder of a direct-acting pump or compressor by a valve which has a combined oscillating and reciprocating movement and is actuated by fluid and mechanical means. The valve f is arranged co-axial with a ported auxiliary piston j, is provided with tongues f<1>, which engage flattened recesses in the sides of the piston, and is free to move radially. Both the valve and the piston receive an oscillating movement from the cross-head. The shape of the exhaust port and the edges of the valve are shown in Fig. 2. The cylinder steam and exhaust ports are shown at c, e, d. The oscillating movement partly effects the cut-off, which is completed by the longitudinal movement that effects the admission. The exhaust from the main cylinder is cut off by the oscillating movement before the throw of the valve takes place. The valvechest is provided with passages g, g<1>, which alternately communicate with the admission and exhaust. The liners n, n<1> have admission ports k<1> ... k<5>, and exhaust ports o, o<1>, connected to the ports g, g<1>, which are controlled by ports m, m<1> in and connected to the ends of the auxiliary piston. The ports k<1> ... k<5> are controlled by regulating-valves l. In the construction described, suitable for pumping in compressible fluids, the work throughout each stroke is the same and constant. In pumps where the work on one side is less than that on the other, for example in single-acting airpumps, the valve is given more lap on one side so that steam is admitted in less quantities.