GB659094A - Improvements in or relating to combustion apparatus for burning solid fuel in comminuted or pulverulent form - Google Patents

Abstract

659,094. Pulverlent - fuel burners. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. Oct. 4, 1948, No. 25837. [Class 75(i)] In combustior apparatus whereir an air stream carry ing solid fuelpar ticles is led into a vortex chamber o: circular or annular section so that the airstream flows ir vortex manner around the axis oj the chamber in such a way that only particles of and below a predetermined maximum size, and having an equilibrium both of radial distance from the said axis which is less than the radius of the discharge outlet from said chamber, are discharged through said outlet into a combustion chamber, the combustion chamber comprises a hollow cap 4 of conical or frusto-spherical form having its outer end open and facing downstream and forming the upstream boundary of a primary combustion zone 4a, the walls 1a, 1b of the vortex chamber 1 being so formed that the fuel particles are induced to undergo substantial oscillations about their mean equilibrium paths. The mixture of pulverulent fuel and air is passed into the vortex chamber 1 through a tangential inlet 2, and fuel particles below a predetermined size are discharged though an outlet 3, as a conical spray, into the combustion zone 4a. A surrounding tubular duct 9 contains a fast-moving air stream which passes through an opening 5a around the discharge outlet 3 and containing swirling vanes 7 to provide primary air for combustion. The cap 4 may also comprise perforations 8 to admit further primary air, and an annular gap 10 is provided between the members 4, 9 for the passage of a layer of cooling air around the combustion zone Fuel particles which are initially too large to issue from the chamber 1 will revolve within it at a radius larger than the radius of the outlet 3 until they are reduced in size by mutual attrition until their radius of revolution is small enough to allow them to pass through the outlet 3. To assist in . the attrition of the particles projections or serrations 11 are provided on the walls 1a, 1b of the chamber 1, which preferably converge towards each' other from the axis towards the periphery of the chamber 1 in the manner described in Specification 639,483. A liquid fuel injector 12 is disposed axially of the outlet 3 and provides a pilot flame for igniting the pulverulent fuel which is discontinued when ignition has been effected. Specification 636,624, [Group XII], is referred to. The Provisional Specification refers in addition to Specifications 338,108, [Class 51(i)], and 639,468, [Group XII].