GB412033A - Improvements in air supply control systems for furnaces - Google Patents

Abstract

412,033. Regulating air supply to furnaces. AMERICAN ENGINEERING CO., Aramings Avenue, Philadelphia, U.S.A. May 24, 1933, No. 15015. Convention date, May 27, 1932. [Class 51 (i).] An air supply control system for furnaces comprises a forced draught chamber from which air under pressure is supplied through ducts to different parts of the fuel bed each duct being provided with an adjustable inlet controlled by the pressure in the chamber and with means for throttling the flow of air in the duct inversely to the resistance offered by the fuel bed. Fig. 1 shows an underfeed stoker the tuyeres 3 of which are supplied through separate ducts 17 from an air pressure chamber 8. Associated with each duct 17 is a control box 34, Figs. 1 and 5, provided with rotary dampers 36, 37 the damper 36 being controlled by pressure in the chamber 8 and the damper 37 by pressure in the control box. The dampers 36 of all the control boxes are interconnected by a system of rods and levers so as to be operated simultaneously from an air pressure motor consisting as shown in Fig. 2 of a number of floating bells 84<a>-84<h> subjected on their upper surfaces to the pressure in the chamber 8 through pipes 102 and on their under surfaces to atmospheric pressure. The bells actuate levers 104 which are interconnected by rods 107 and are connected to the common actuating rod 111 for operating the dampers 36. The bells are provided with adjustable counterweights opposing the air pressure in the chamber 8 which varies with the load and the dampers 36 are actuated accordingly. The dampers 37 are actuated by bells 152, Figs. 5 and 10, exposed to air pressure in the control box 34 and to the pressure in the chamber 8 and connected by rods 155, levers 158 and links 164 to the dampers. The levers 158 carry adjustable counterweights 162 and a box 167 containing a heavy liquid such as mercury. Any ashes &c. which may fall through the fuel supporting surfaces into the ducts 17 or into chambers at the front and rear of the ducts is led into conduits 28 and 32 connected to a hopper 29. Suitable closure valves are provided at the lower ends of the ducts 17 adapted to be operated periodically for the discharge of ashes.