Patent GB-145458-A (GB)
Title: Improvements in underfeed furnaces
IPC: F23K3/12
Filed: 1920-06-18
Abstract: 145,458. Ratel, M. March 30, 1914, [Con vention date]. Mechanical stoking; grates; ash-pits.-In an underfed furnace of the kind in which fuel is fed into parallel troughs provided at their upper parts with air blast tuyeres, the troughs are provided with reciprocating members which agitate and distribute the fuel, and means are provided at the rear of the grate for crushing, cooling, and removing ash and clinker. As shown in Fig. 1, fuel is fed into the inclined troughs by reciprocating plungers 3 provided with lugs 9 adapted to engage with adjustable pins 8 situated in holes within extensions 7 of rods 6 carrying fuel-distributors 4 of the general form shown in Figs. 3, 4, and 5. By adjusting the position of the pins 8, the stroke of the fuel distributors 4 may be varied. Each trough is provided with two juxtaposed series of distributors, and in order more effectively to distribute and break up the fuel in the troughs, the rearward stroke of the two sets of distributors is interrupted at different positions. As shown in Figs. 6 and 7, the lug 9, after leaving the forward pins 8<1>, engages on its return movement with a pivoted pawl 10 mounted loosely upon a pin 15 and connected by a projection 16 and a spring to a projection 17 secured to a lever 11, pivoted at 15, and provided with a roller 12 moving between guide rails 13, 14. In the position shown, the pawl 10 is not free to turn but moves with the lug 9 and carries the rod 7 and distributors forward. Upon the roller 12 becoming disengaged from the tracks, the pawl 10 tilts and the distributors remain stationary until the lug 9 engages with the rear pin 8<11> and again moves them towards the rear. During the forward stroke of the ram 3, the lug 9 engages with the pawl 10, which is again in its normal position, but is free to tilt against the action of the spring and allow the lug to pass without moving the distributors until it engages with the forward pin 8<1>. By arranging the guide rails 13, 14 of the juxtaposed series of distributors at different positions, the times at which the two series are brought to rest in their rearward movement may be different. After leaving the troughs, the incandescent fuel passes over perforated inclined grates 19 and devices such as 21, 23 for the injection of steam, fluids, moist air &c. to effect disintegration and cooling. A reciprocating plunger 22 and grate 24 serve to effect crushing and removal of the ash and clinker. Figs. 9 and 10 show a modification in which the fuel is fed into a series of horizontal troughs 28 having tuyeres 29 and fuel distributors 31 pivoted to reciprocating bars 35 and adapted to move vertically in the troughs. The distributors 31 are moved up and down by links 32 which engage by means of rollers 33 with an undulating track 34. The bars 35 may be provided with two series of distributors arranged side by side and adapted to move in opposite directions by arranging the links 32 in separate tracks having the undulations in different phase. The grate 38 may be fixed or movable and supplied with an air blast from the chamber 40. A reciprocating crusher 41 and adjustable plates 42 for the removal of ash &c. are provided.