GB1426091A - Blue-flame retention gun burners and heat exchanger systems - Google Patents

Abstract

1426091 Liquid fuel burners F W BAILEY 9 Feb 1973 [10 Feb 1972] 6581/73 Heading F4T A process of burning liquid hydrocarbon fuel in a burner having a sleeve with an open breech end and an outlet mouth opening into a combustion chamber comprises the steps of spraying the fuel from a nozzle into a region disposed in the sleeve near the mouth thereof, supplying a major portion of combustion air as multiple jets directed into and through the sleeve, cooling the nozzle with a minor portion of combustion air and discharging said minor proportion of combustion air directly into said region, recirculating gaseous combustion products from the combustion chamber to the breech end of and into the sleeve, the recirculating combustion products flowing in heatexchange relationship with a fluid-cooled heatexchanger, and mixing the combustion air jets with the recirculating combustion products in a zone positioned upstream of the fuel injection region so that a stable blue flame is produced in the combustion chamber having a low nitric oxide and low particulate emission level. The burner comprises a fuel inlet pipe 44 having an atomizing nozzle 46 and being located in a tube (84) to which the minor portion of combustion air is supplied through inlets 100, this air exiting as divergent jets 135 through outlets 133. The tube (84) extends into a sleeve 134 to which a major portion of combustion air is supplied as jets 102 emerging from adjustable orifices 72 in the base of a cupshaped member 70 defining a plenum chamber 66 to which air is supplied by a blower. The sleeve 134 opens into a combustion chamber 106 and has a flange 138 forming a baffle for directing some of the combustion products into a recirculation passage 139, 140 leading to an annular zone 104 where the combustion products mix with air jets 102. The size of orifices 72 is adjusted by means of an apertured disc 82 secured to tube 84 which is keyed to a support 96 for ignition electrodes, support 96 being rotated by means of arm 108. A spring 92 serves to retain tube 84 in position and maintain disc 82 in contact with the base of member 70. An abrupt increase in cross-section is provided adjacent mouth 136 of sleeve 134 so that a vortex 168 serving as a flame stabilizer is formed. In a modification the effective size of orifices 72 is adjustable by means of plugs 172 which are movable axially of fuel supply pipe 44. Two of the plugs are supports for ignition electrodes 118, and the plugs may be provided with fins 188. The combustion chamber 106 is located in a heat-exchanger 14 containing for example water, the refractory material 150 being removed from a portion 151 of the chamber wall adjacent the flange 138 and the heat exchanger having a metal wall 144. Some of the combustion products pass into a flue (154, Fig. 1, not shown) and are directed into tubes (156) extending through the heat exchanger.