GB388415A - Improvements in heat treating furnaces - Google Patents

Abstract

388,415. Metal-heating furnaces. HAYES, C. I., 129, Baker Street, Providence, Rhode Island, U.S.A. July 22; 1931, No. 20907. Convention date, Aug. 28, 1930. [Class 51 (ii).] Gases, supplying; air, preventing admission of ; indicators.-In a metal-heating furnace of the kind in which the work is enveloped, during heating by electric resistance elements 19, in an atmosphere of combustion products which are generated by the combustion of gas and air in a chamber 23 and projected through a slot 24 so as to form an air-excluding curtain across the charging throat 13, means, operated by the furnace door 14, are provided for increasing the supply of gases through the slot 24 as the door is opened. As shown, the gas and air supply pipes 25, 25<1> are each fitted with two valves 29, 33, and 31, 34 in the main pipe lines and further valves 30, 32 in byepass lines 27, 28. The valves 33, 34 are connected by links 35, 36, 37 and a rod 38 to the shaft 40 carrying the pulleys 16 which effect the raising and lowering of the door 14. The setting of the hand valves 30, 32 controls the proportions of gas and air normally delivered to the combustion chamber 23, while the proportions of additional gas and air supplied when the valves 33, 34 are opened by raising the door 14 are controlled by the setting of the hand valves 29, 31. Manometers 41, 42, connected to flow indicators 43, 44, are provided in the gas and air lines 25, 25<1>. Fig. 5 shows a modified connection between the rod 38 and the valves 33, 34 to enable the latter to be adjusted by hand if necessary. A pin 47, forming the connection between the links 35, 37, is normally held by a spring 49 in a slot 46 which communicates with a second slot 45 formed in the lower end of the rod 38 ; on release of the pin 47 from the slot 46, the valves 33, 34 may be manually adjusted by the handle 48.