GB321172A - Improvements in or relating to powdered fuel burners - Google Patents

Abstract

321,172. Nielsen, H., and Laing, B. May 1, 1928. Pulverulen-fuel burners.-A mixture of powdered fuel and air supplied under pressure to a burner is further mixed with at least the total theoretical volume of air required for the complete combustion of the fuel and the mixture is allowed to expand before reaching the burner outlets so as to vary the velocity of the air in respect to the suspended solid fuel particles. The mixture is split up to a large number of independent streams at the burner outlets. Fig. 1 shows a burner in which a mixture of fuel and primary air entering tangentially a chamber a<2> is mixed on leaving a nozzle a<3> in a chamber a<4> with secondary air, preferably preheated, supplied through a tangential inlet A<2>. The mixture passes through a constriction a<5> in the burner casing to a flared conduit a<6> which is fitted at its discharge end with a grid formed with a number of openings D of varying cross-section. The grid may consist of two plates d, d', the plate d being composed of metal or refractory material, of relatively high heat conductivity and the plate d<1> being composed of metal &c. highly resistant to heat but not necessarily highly conducting. The plates d, d<1> may be detachably secured together or may be mounted so as to be relatively movable so as to clear the parts of adherent dust or clinker. The openings D may be of Venturi cross-section so that the velocity of the mixture exceeds that of flame propagation and flashbacks. are prevented. The supply of fuel and primary air is regulated by an adjustable valve B provided with inclined vanes b<2>, Fig. 6, to impart a whirling movement. The secondary air may be admitted through variable inlets fitted with inclined vanes. Provision may be made for cooling the burner by air or water and the rear part of the burner may be hinged at its fixing flange A<3> so as to permit of access to the interior.