GB856470A - Improvements in or relating to control apparatus for boilers - Google Patents

Abstract

856,470. Controlling furnace burners. CENTRAL ELECTRICITY GENERATING BOARD, and EDLEY, W. Sept. 5, 1958 [Oct. 2, 1957], No. 30912/57. Class 51 (1). [Also in Group XXIX] Control apparatus for a boiler furnace 1 fired with a primary solid fuel at 2 or by a secondary fuel e.g. oil at burner 3 comprises a first control device 12 e.g. a floating proportional controller with diaphragm operated pilot valves, receiving a signal of the steam pressure e.g. via a master pressure controller 14, a manual or automatic selecting valve 25 and pipe 13, and signals from the input and output of a solid fuel pulverizer 8 via pipes 16, 17 and emitting at 18 a primary fuel supply indicating signal, a second control device 19 receiving a signal of the steam pressure via pipe 20 and the primary fuel supply signal 18 and emitting at 21 a fuel need signal, and a start device 22 operable by a fuel need signal of predetermined value from the second control device for initiating operation of the secondary burner via a control panel 4. With solid fuelling, the signal from 26 acts via 28 on a regulator 7 operating an automatic feeder 6 controlling the feed from the bunker 5 to the pulverizer, while a fan 10 feeds the pulverized fuel to the burner 2. On the failure of the solid fuelling, e.g. by clogging, the signal from 26 is of such a value as to operate a pressure gauge, the indicator 23 of which actuates a switch which brings the secondary burner into operation. When the primary supply is restored, valves 25, 26 are manually operated to recondition the apparatus for automatic burner control, and then act as air pressure reducing valves for lines 13, 21. The apparatus may be electrically or hydraulically operated.