Furnace Wall Burners: Industrial Furnace Burner Type
Controlled radiant heat provides improved product quality and enhanced productivity for a wide variety of materials.
Selas Duradiant burners are cup-shaped, ceramic precision combustion tools which radiate heat to work pieces intimately, without flame impingement. The unusual freedom in placement and broad throttling ranges permit them to transfer heat in a variety of controlled patterns to suit many production requirements. Radiant heat distribution can be concentrated to simplify "spot" heating of product parts, patterned to meet uneven heat requirements, or arranged uniformly over wide areas.
Open Firing Duradiant burners mount in any position to deliver fast, controlled heating for metals, ceramics, chemicals, petroleum, glass and more. Designed for non-furnace use, open firing Duradiant burners are available in a range of sizes, cup contours and protective housings.
Line Arrangement Duradiant burners provide close coupling of radiant heat sources, and are ideal for light-duty heating applications. Designed essentially for heating moving webs, these burners are often used in "line" arrangements where relatively "light" heating jobs are to be performed.
Duradiant semi-furnace burners are designed for mounting into vertical refractory walls or panels where 4-1/2" (114mm) thick wall construction is acceptable for service. All critical metallic parts are fabricated of heat resistant alloy steel.
Light duty-panel type Duradiant burners are intended for use in furnace walls (and some types for roofs) of varying thicknesses and where close burner spacing is a requirement. These burners are normally recommended for use where temperatures do not exceed 2000°F (1093°C).
The Duradiant furnace wall burner line is comprised of two types designed for use above and below 2000°F (1093°C) each manufactured in a high and low capacity range. All parts exposed to furnace temperature are ceramic in the high temperature burners; the low temperature burners employ alloy tipholder components.
The Duradiant VA burner provides a wide operating range with minimum pressure change. It offers a 20:1 turndown or higher using a variable area principle. The VA burner provides faster heating, finer control and improved product quality.
FEATURES & BENEFITS
- High-speed radiant heat transfer allows for closer proximity between heat source and work-piece without flame impingement
- Differential heating possible with burner outputs of varying intensities
- Wide burner throttling ranges
- Improved product quality with minimal exposure to the effects of high temperatures
OPERATING PRINCIPLES
As the diagram shows, air/gas mixture enters the burner tube and flows to the burner tip (1). After the mixture passes through the tip's threaded refractory orifices (2), it is distributed radially and burns within the refractory cup (3) in a petal-shaped formation. The inner contour of the cup is formed so that its surface is always "washed" by hot combustion products, regardless of operating rates.
Because the refractory cup surface is heated by high velocity combustion products at their highest temperature, it becomes incandescent. Combustion is always completed within the cup. Any "haze" seen beyond the cup is caused by incandescent products of combustion.
Radiant heat from duradiant burners can be directed accurately and travels more rapidly than convected heat from hot gases.