GB313100A - Improvements in and relating to powdered fuel burners - Google Patents

Abstract

313,100. Ha.zlehurst, H. E., and Margetson, O. Dec. 7, 1927. Pulverulent-fuel burners. - The mixture of powdered fuel and its carrying air is divided prior to its admission into the combustion chamber into two streams, one stream preferably containing one and a quarter times and the other preferably containing not more than one third the air necessary for the combustion of the contained fuel so that the rate of flame propagation in both streams is relatively low; the two streams are discharged into the combustion chamber in such a manner as to converge on each other and form a mixture in which the rate of flame propagation is relatively high. The division may be effected by a cyclone separator before the mixture reaches the burner or may be effected in the burner itself. Fig. 1 shows one form of burner in which the mixture of fuel and air is supplied to a chamber a through a tangential inlet b. The heavier fuel particles travel round the circumference of the chamber a and are discharged through an annular outlet d with sufficient air to form a stream of rich mixture while a weak mixture of the lighter fuel particles and air passes through an outlet e into an annular chamber f surrounding the chamber a and issuing through an annular outlet g converges on to the stream of rich mixture. The inner edge of the outlet d is formed by an adjustable tubular member h through which secondary air or gaseous fuel may be supplied, and in which an oil burner may be arranged. Additional air may also be supplied through adjustable ports k. Fig. 3 shows another form of burner in which the fuel mixture is supplied through a curved pipe l and the lighter fuel particles are diverted by a hinged flap m into an annular chamber p having a converging discharge, passage r while the heavier fuel particles are discharged through a central passage g. The passages r, g are provided with inclined ribs t, u which cause the weak and rich streams of mixture to rotate in opposite directions. Burners may also be constructed with flat elongated discharge passages.