GB555737A - An improved method of and apparatus for regulating the draft in a steam generator - Google Patents

Abstract

555,737. Regulating draught. McINTOSH, R. R. March 2, 1942, No. 2731. Convention date, March 1, 1941. [Class 51 (i)] The draught in a locomotive smoke box is regulated by admitting air automatically thereto when the suction pressure therein exceeds a predetermined value, the air admission being stopped when it is desired to raise the suction pressure to a higher level for higher rates of fuel consumption. As shown in Fig. 5, a locomotive smoke box 1 is provided with air inlets 31, 40 having valves 18 loaded by counterweights 24 which are such that the valve in the inlet 40 opens at low suction pressures and low rates of fuel consumption to check the draught while the valve in the inlet 31 opens at high suction pressures and at high rates of fuel consumption. Instead of disc valves 18 hinged valves may be employed and instead of counterweights, springs may be employed to load the valves. The inlet 40 is provided with louvre valves 42, Figs. 5 and 10, which are actuated by fluid pressure acting on a piston 53, the rod of which actuates the louvres against the action of a spring 52. The fluid pressure may be that driving a mechanical stoker so that at high fuel consumption rates the steam pressure closes the louvres and the suction pressure in the smoke box increases and is maintained at a predetermined higher level and under the control of air admitted by the inlet 13. Where oil fuel is employed the fluid pressure supply to the piston 53 is controlled simultaneously with the oil supply. Instead of a single acting piston acting against a spring for operating the louvre valves 42, a double acting piston may be employed. The smokebox may be provided with partitions 9a, 84 separating the gases passing through the upper and lower smoke tubes of the boiler, the partition 9a having screens 77, 78 and adjustable plates 79, 80. A pipe extending from a point adjacent the lower end of the stack to the base of the smokebox is employed for the removal of deposits at the base of the smokebox.