Patent GB-225574-A (GB)
Title: Improvements in mechanical stokers for furnaces
IPC: F23K3/00
Filed: 1924-12-01
Abstract: 225,574. Pastrnak, A. Nov. 30, 1923, [Convention date]. Addition to 193,007. Mechanical stoking.-A modified form of the fuel feeding and distributing and ash-removing device for furnaces described in the parent Specification comprises a reciprocating frame 8 carrying a pivoted fuel receptacle 28, fed with fuel from a hopper 19 and discharged automatically at the rear of the grate 2, and also pivoted blades 11 which move the fuel progressively towards the front of the furnace and finally discharge the ashes through a channel 89 into a receptacle 87 provided with a grate 88 on which the unburnt fuel is consumed, the combustion products passing through the channel 89 to the main furnace. The frame 8 is mounted on rollers adapted to run on tracks at the sides of the furnace and in a closed casing or housing 90 arranged at the front of the furnace. When the frame 8 reaches the position shown in Fig. 1, the bars 12 interconnecting the pivoted receptacle and pivoted blades are released from hooks 41, which hold them in their raised position, and the receptacle 28 and blades 11 then occupy the position shown, the fuel being delivered on to the plate 3<1>. A device 32 serves to direct the fuel durring its delivery. Upon withdrawal of the frame 8, the fuel is moved forward by the bar 30 attached to the forward end of the receptacle 28 and by the blades 11, the rear one of which is provided with a roller 39 adapted to travel on a stepped track 92, 93, 94 extending into the housing 90 at 38. As the roller 37 moves up the inclined portion 92 of the track, the blades are lifted and then remain stationary during the passage of the roller over the portion 92 of the track which is adjustable in height to vary the depth of the fuel bed. In moving up on to the track 38 the blades and receptacle are raised further and are finally retained in the raised position by the hooks 41 which engage automatically with the transverse rod 42 connecting the bars 12. As the frame reaches its outermost position, the rollers 33 on the receptacle 28 tilt the pivoted bottom 20 of the fuel hopper and the receptacle is again filled. The frame is actuated by a chain 46 driven from a power shaft 53, in which is interposed reversing bevel gear, and worm gearing 48, 49. The motion of the frame is reversed or stopped by the engagement of the frame with projections 67, 68 on a rod 66 which actuates a bell-crank lever provided with a fork 65, Fig. 3, adapted to engage with a counterweighted pivoted rod 61 having a slot engaging with a pin 58 for operating the clutch 56 coupling either of the bevel wheels 51, 52 to the bevel wheel 50 on the shaft of the worm 49. In order that the frame may remain stationary in its housing for a predetermined period, the clutch is prevented from engaging with the forward driving-gear by a cam-shaped disc 76 or a ratchet wheel 69 driven from the power shaft 53. The disc prevents the clutchoperating rod 61 from engaging the clutch with the bevel wheel 51 until the flat portion of the cam makes contact with the rod when the forward movement of the frame is then effected. The rate of rotation of the ratchet-wheel is varied by a mask 77, and enlarged teeth are provided on the ratchet-wheel for effecting rapid operation of the cam. A worm conveyer 84 in the ash-pit serves to remove the ashes into a casing 85 communicating with the ash receptacle 87. The frame 8 carries a toothed roller 35 for levelling the fuel and breaking clinker.