Patent GB-439213-A (GB)
Title: Improvements in or relating to rodless slide-valve gear for double-acting piston engines
IPC: F01L25/06
Filed: 1934-09-22
Abstract: 439,213. Engine valve-gears. TOLKIEN, F., 18, Lister Kirchweg, Hanover, Germany, and KNORR-BREMSE AKT.-GES., 9, Neue Bahnhofstrasse, Berlin. Sept. 22, 1934, No. 27294. Convention date, Oct. 14, 1933. [Class 122 (ii)] Fluid-actuated gears, with auxiliary distributing valves.-In a simple or compound, double-acting engine, the distribution is effected by a differential piston valve provided with distributing-heads and actuating- heads, and which is connected to auxiliary valves arranged in chests at the ends of the main chest by tappet rods. The construction facilitates starting from any of its possible positions and for any position of the working piston or pistons of the engine. The distributing-heads are unsymmetrically arranged on the valve, and the actuating-heads are of different diameters. The starting movement of the valve is effected by the pressure fluid acting on one of its actuating-heads, or by the differential action on different heads. In no position of the valve can the inlet be covered completely. In the construction shown, the valve has distributing-heads d<0>, d<1>, and actuating-heads e<1>, e<2> Passages a<1>, a<2> lead from the chest c to the main cylinder ends, and auxiliary passages n, n<2>, n<1>, n<3> lead to the ends f, f<3> of the auxiliary chests c<1>, c<2> which house valves e, e<3> connected by tappets e<4>, e<6>, e<5>, e<7> to the main valve. Annular spaces f<1>, f<2> are put into communication with the cylinder and the exhaust by passages h<1>, h<2>, m, m<1> grooves g<1>, g<2> and passages o<1>, o<2> respectively. The valve chest has inlet and exhaust ports E, A communicating with fluid pressure and exhaust valve chambers r, r<1> respectively. The valve is hollow and is provided with transverse ports k<1>, k<2>. In the position of the gear shown, steam from the inlet A passes to the two ends of the cylinder a and through passages m, m<1>, grooves g<1>, g<2>, passages h<1>, h<2> to the chambers f<1>, f<2>. The valve moves downwards, the difference in area between the heads e<2>, e<1> being greater than that between heads e<1> and d<0>. Steam is supplied to the top of the main cylinder only ; the spaces f<2>, f<3> being connected to exhaust ; the passage m is cut off, and the chamber f<1> is put to exhaust. Live steam from the pipe n to the valve e moves this valve and the main valve into contact and holds them down until the pipe m<1> is uncovered by the piston b to effect the up movement of the valves. The main valve in its up and down motions passes the mid position before the heads e<6>, e<7> engage the auxiliary valves, and these are balanced by steam supplied through passages n, m or n<1>, ml during the initial motion of the main piston. When the valve e, pushed up by the main valve, connects passages m, h<1>, the chamber f<1> is put to exhaust. The auxiliary valve e<3> at first closes m<1> and then opens passage o<2> whereby chamber f<2> is put to exhaust, and steam in chamber f<3> moves the valves to their top position. The starting action is also described from a position of rest with the main valve in the down position and the end valves in engagement therewith. In a double-acting, two-cylinder, tandem compound engine, the main valve has. three heads between the heads e<1>, e<2>. The heads are unsymmetrical, and can never supply steam to the two ends of the low-pressure cylinder simultaneously. The starting of the engine from various positions of rest both of the main valve and of the main piston, is described. The steam led from the H.P. cylinder to the chambers f<1>, f<2> expands to the L.P. cylinder.