GB498568A - Means for preventing overheating of the tubes of tubular heaters for gases - Google Patents

Abstract

498,568. Preventing overheating of tubular air or gas heaters. AKT.-GES. FUR TECHNISCHE STUDIEN. Feb. 28, 1938, No. 6278. Convention date, March 1, 1937. [Class 51 (i)] [Also in Group XIII] In a tubular air or gas heater comprising tubes wholly or in part disposed in the combustion chamber of a furnace so as to line the walls thereof, combustion products are returned by a blower to the combustion chamber under the control of a temperature responsive device within the combustion chamber. The Figure shows a heater 2 wherein air or gas to be heated is supplied by a pipe 1 to a header 3 from which it passes through tubes 4 lining the combustion chamber 5 and passing through communicating flues to an upper header 8 and outlet 9. Air and fuel are supplied through pipes 13, 14 to the lower end of the combustion chamber 5 from which combustion products escape through the flues to an outlet 10 and are also drawn by a blower 11 through a pipe 12 and returned to the combustion chamber through the pipe 12<1>. Thermo-elements 15, 16 in the combustion chamber or in contact with the tubes therein control the speed of the blower motor or adjust the blades of the blower. Alternatively, the thermo-elements may control a damper in the pipe leading to or from the blower.