GB402934A - New or improved method of and apparatus for admitting secondary combustion air into the combustion chambers of furnaces - Google Patents

Abstract

402,934. Supplying air to furnaces. PETERSEN, K., Buddinge, Denmark. Dec. 1, 1932, No. 34071. [Class 51 (i).] The regulation of the amount of secondary air admitted to the combustion chamber a, Fig. 1, of a furnace fired with solid fuel on a grate is effected by a complete shutting off or a complete opening of a greater or smaller number of secondary air inlet openings d<1>, d<2>, d', d<4> which are fed with air from a common blower or the like so proportioned or driven that the velocity of admission of the air is approximately independent of the number of openings in operation or increases slightly for a smaller number of openings. A modified form of inlet member comprises a nozzle formed by two pivoted curved tongues k, Fig. 3, which are either swung together to close the inlet or are separated by a fixed distance. They may be adjusted in non-symmetrical position to admit the air in an oblique direction. In another form, Fig. 2 an air inlet is divided by partitions into compartments f<1>, f<2>, f<3> and provided with a regulating flap h serving not only for completely closing the inlet but also for stepwise opening. Such an inlet may be supplemented by a rotatable nozzle, Fig. 5, having coaxial outlet channels n<1>, n2, n<3> provided with blinders such as q2 which give a pulsating outflow of air. The nozzle may be rotated by a small turbine wheel s or may be independently driven. The air supply may also be shifted to different points of introduction. Means may be provided for closing some or all of the secondary air inlet openings in sequence at predetermined intervals of time during the distilling of the fuel. A shaft 7, Fig. 7, is rotated from a motor 1 through a friction drive 3, 4, a worm 5, worm wheel 6 loosely mounted on the shaft and a second friction drive 9, 10 and carries a number of cams 11, a disc 12 with a cam finger 13 and a pinion 14. By adjustment of the wheel 3 the shaft may be made to rotate once during successive firings. Each of the cams 11 has three concentric circular portions of different radii and serves to operate, as shown in Fig. 8, the controlling flap of an inlet member of the kind shown in Fig. 2. At the end of a firing period the cam finger 13 by engaging a roller 15 serves to move the tooth 20 of a pawl 19 to a position above a slide 32 having a notch 33 and also to ring a bell 40. On the opening of the fire door 28, the pawl is moved through lever mechanism to engage in the notch 33. On closing the door the pawl moves the slide to the right, as seen in Fig. 9, causing a wedge 31 to lift a rack 29 and through the pinion 14 turn the shaft 7 back to its starting position. The pawl is subsequently released by a roller 38 and the slide returned by a spring 36.