Book - School of Science and Technology

288 Boilers and firing equipmentNeat flame burner. As the name suggests, these are naturally aerated burners havingshielded jets and their use is generally confined to conversion exercises for boilers ratedat not much more than 50 kW. Such a burner is illustrated in Figure 10.22.Atmospheric burners. Since a fuel gas reaches the point of use under pressure, it is logicalto make use of this potential energy to induce a proportion of the air required forcombustion into a mixing tube. This, the principle used in the Bunsen burner, isadapted also for the atmospheric burner.Packaged burners. The introduction of a fan powered air supply is the principal distinguishingfeature of this general type. Discharged at the burner face, the air supply mixesthere with the fuel which is admitted via control ports. In many respects the concepthere may be compared with that of gun-type oil burners.It should be noted that whilst the general thrust of the comments made above and of thosewhich follow is directed to the burning of North Sea gas derived from the public supply,this is not to suggest that the equipment described is exclusive to that fuel. On thecontrary, much if not all of it may be used equally satisfactorily with LPG when appropriateadjustments have been made to jet sizes and to air supplies.Atmospheric burnersThese represent a type of equipment which follows the traditional pattern associated withthe firing of cast-iron sectional boilers purpose designed for this fuel, as illustrated inDraughtdiverterGasgovernorAtmosphericburnerPilot lineFigure 10.23 Atmospheric gas burner and boiler