Patent GB-400196-A (GB)
Title: Improved means for operating and controlling the grates of furnaces, distilling retorts and the like
IPC: F23H9/00
Filed: 1932-03-16
Abstract: 400,196. Furnace grates. NESFIELD, A. G., Glen House, HighclifFe-on-Sea, Hampshire, and ROBINSON, H., 11, King Street, St. James's, London. March 16, 1932, No. 7825. [Class 51 (i).] Apparatus for operating and controlling grates of the reciprocating bar type comprises a plurality of double acting hydraulic cylinders the pistons of which are loosely connected to the fire bars, each of the cylinders being connected to a master valve communicating, in the case of boiler furnaces with the boiler feed pump or, in the case of distillation retorts, with a steam driven pump. As shown, Fig. 5, the hydraulic fire bar cylinders 2 are formed in a single casting 3 provided with an inlet port 8 and an exhaust port 9 which are made common to all the cylinders by means of ports 10 in the cylinder walls. The outer ends of the cylinders are connected singly or in groups (as shown, in pairs) to a master control valve. The piston 5 of each cylinder is provided at its outer end with a groove 6 adapted to engage loosely and removably with an open-ended slot formed in the end of the corresponding fire bar. The control valve, Fig. 7 and Figs. 9 to 11 comprises three cylinders 14, 15, 16 having piston-rods 17, 18, 19 each provided with two pistons. The rods are connected at their ends by cross-bars 20, 21, and are reciprocated by means of the cylinder 15 which is provided at the ends with ports 42, 43 connected alternately to supply and exhaust by means of pipes 44, 45 and a rotary valve 41 operated by tappets 51, 52 on a rod 53 connected to the cross-bars 20, 21. The cylinder 16 controls the communication between an exhaust port 35x and a port 35 connected to the common port 9 of the firebar cylinders and also between an exhaust port 34x and a group of axially spaced ports 30 .. 34 connected by pipes 13 to the ports 12 of the fire bar cylinders. The cylinder 14 controls the supply of pressure liquid from ports 26x, 27x, connected with the main supply line, to ports 26, 27 connected respectively to the common port 8 and to the ports 12 of the fire bar cylinders. The connection between the port 27 and the ports 12 is made through a valve box 36 having non- return valves in order to prevent a short circuit between the various fire bar cylinders when ports 12 are being connected to exhaust in sequence. In operation, in the position shown in the Figures, pressure liquid acting on piston 23 will move all the pistons to the left thus exhausting in sequence from the ports 12 and simultaneously supplying pressure liquid to the common port 8 to effect forward movement of the firebars in a predetermined sequence. At the end of the stroke the tappet 51 effects reversal of the valve 41 and the pistons move to the right, cutting off the supply from port 8 and the exhaust from ports 12 by means of pistons 24, 28 and connecting port 9 to exhaust and ports 12 to pressure by means of pistons 29, 25 thus effecting simultaneous backward movement of the firebars. In a modified form, Figs. 15 and 16, the cylinders and piston valves are replaced by cam-bars and poppet valves. Cam-bars 67, 68 are reciprocated simultaneously by means of a piston-rod 59 actuated by a piston 60 operating in a cylinder 56 the opposite ends of which are alternately connected to supply 84 and exhaust 64 by means of a slide valve 65. The valve 65 is actuated by liquid pressure in chambers 87, 88 under the control of valves 74, 77 operated by the cam-bar 68. Connection from the pressure supply main 83 to the common port 8 and to the ports 12 is controlled by valves 75, 76 respectively operated bv cam-bar 68. Connection from the main exhaust line 82 to the common port 9 and to the ports 12 is controlled by valve 79 and group of valves 69 .. 73 respectively operated by cam-bar 67. The pressure supply from valve 76 to pipes 13 and ports 12 is made through non-return valves 94 corresponding to the valve box 36.