Patent GB-308208-A (GB)
IPC: F23K3/12
Filed: 1929-03-05
Abstract: 308,208. Alpern, M. March 19, 1928, [Convention date]. Pneumatic conveyers.-In an air supply system for furnaces of the kind in which the air supply to the fire bed is automatically controlled in accordance with the resistance offered to its flow a number of air supply outlets are provided beneath the fire bed each having associated therewith means for controlling the flow of air therethrough, the controlling means for the various outlets being interconnected so that the aggregate flow through the outlets is constant. Figs. 4 and 5 show in longitudinal and cross section respectively one of the tuyere boxes of an under feed stoker defined by side walls 6 and tuyeres 7. The box is divided into a number of compartments each containing the control mechanism shown more clearly in Fig. 5. A control casing 27, divided into a damper portion 38 and a motor part 39, connects a nozzle 13 opening below the corresponding set of tuyeres with the wind box or ashpit 12 common to the whole grate. A pair of dampers 50 pivoted at 51 are connected by links 55 to brackets 58 on motor elements 43, each comprising a compound plate 71, 72 pivoted at 44 and cross connected at their lower free ends by links 46, 47. A specially shaped throat 42 between the compartments 38, 39, in conjunction with the curved upper ends 75 of the motor elements determines a desired relation between the pressure between the motor plates and that behind them (at 38<a>). Adjustment of the apparatus is provided for by screws 78 determining the distance apart of the plates 71, 72 of the motor elements and by making the links 55 adjustable in length. Both these adjustments are effected from the ashpit by special tools. In operation should the resistance, to flow drop, due to a. local thinning of the fuel, the resulting increased flow of air causes a relative reduction of pressure behind the motor plates which therefore separate and close the dampers thus reducing the air supply. The opposite action results from' a local increase of resistance. All the motor plates of each control box may be interconnected by a set of balancing levers, indicated at 61, in such a way that operation of one set of plates causes a reversed action of the others and this arrangement may be extended to connect in a similar way the control elements of the whole grate. The rails 45 over which the lower ends of the blades 43 traverse can be tilted to dump ashes by a rock shaft 68 extending to the front of the furnace. To allow for the effects of heat expansion the control casings 27 are not rigidly secured to the nozzles 13 and the control casings for each tuyere box are carried on a supporting frame pivotally mounted at 33 and 35, Fig. 4. In a modification Fig. 12, the dampers 50<b> are vertical and are operated by a single motor element 43<b>. According to the Specification as open to inspection under Sect. 91 (3) (a) the. invention is applicable to ventilation systems, pipe organs, pneumatic conveyers, hot air, steam, vapour or hot water systems, air, gas, steam, oil or water supply systems and hydraulic systems. This subject-matter does not appear in the Specification as accepted.