GB414356A - - Google Patents

Abstract

414,356. Controlling combustion. THORNTON, A. A., 7, Essex Street, Strand, London.-(Bailey Meter Co. ; 1050, Ivanhoe Road, Cleveland, Ohio, U.S.A.) Jan. 31, 1933, No. 2977. [Class 51 (i).] In a steam-boiler or other furnace plant the fuel and air supply to the furnace are controlled primarily in accordance with an output variable such as steam pressure while secondary control of the fuel supply is effected by the relation between the fuel and air supply and also if desired the steam output from the boiler, furnace temperature or composition of the flue gases. As shown in Fig. 1, a steam flow meter 37, air flow meter 40, and fuel supply meter 34 are provided with indicating scales and are interconnected by a system of levers so as to indicate by means of a pointer 50 any departure from normal of the relation between the steam and air flow and the fuel supply. A Bourdon tube 14 operated by steam pressure serves as a primary control for the fuel and air supply and upon departure of steam pressure from the normal raises or lowers a presser bar 16 relatively to a reciprocating member 17, actuated by a cam 21 driven by an electric motor 29, and a double wedge shape member 18 carrying electric contacts 19, 20. Upon one or other of these contacts being closed current flows from the power line 25 through conductor 27 relay 22, or 23 conductor 31 or 32 to the motor 11, for actuating the flue damper 10, conductor 26 to line 24. Simultaneously energization of the relay 22 or 23 effects the operation of the pilot motor 30 through conductor 27 relay 22 or 23 and conductor 33 or 33a for varying the speed of the motor 5 for driving the stoker. In the event of the fuel and air supply and the steam flow not bearing the correct relation, a bar 43 closes one or other of two electric contacts thereon to operate the motor 30 through power line 25 conductor 34 and conductor 45 or 46. If either of the relays 22, 23 is energized the circuit through the conductor 44 is opened. The steam flow meter may be replaced by a meter for indicating the constituents of the flue gases or by a temperature indicating device sensitive to the temperature in the combustion chamber.