The Selas DNS Nozzle Mix burner features a unique cup-like design that allows combustion air and fuel gas to quickly and thoroughly mix at the nozzle. An igniter is then used to start combustion of the air/gas mixture, subjecting it to turbulence so that it burns rapidly and completely within a small area as it sweeps across the cup. This distributes fully reacted combustion products into the furnace where the hot gas heats the work directly. The products of combustion are broadly distributed so they transfer heat to the work evenly, minimizing the localized overheating often caused by concentrated impingement from flame-type burners. The combustion is complete within the cup, so the heat exiting from the cup is uniform, stable and highly controllable. By contrast, the combustion of conventional flame-type burners takes place over a longer period of time with temperature and heat transfer characteristics varying over the length of the flame.
Selas DNS burners eliminate many other deficiencies inherent in conventional furnace firing systems. Flame-type burners require a greater burner-to-workpiece distance to avoid flame impingement, hot spots, scaling and decarburization.This increases furnace size and cost beyond what would be required with DNS burners. Slow fuel/air mixing in flame-type burners necessitates extra air to achieve complete combustion. DNS nozzle-mix burners provide complete combustion without excess air and therefore don’t waste partially burned fuel, thus operating at higher thermal efficiencies and lower stack temperatures.
The DNS burner can be mounted in furnace roofs or walls, of either brick or monolithic refractory construction. Installation can be done in space vacated by removed burners of another type or new mounting arrangements can be made.
Features and Benefits
- Complete, stable combustion within burner cup.
- Rapid, efficient heat transfer and excellent uniformity with burner outputs of varying intensities.
- Adaptable to all standard control and flame safety systems.
- Significant reduction of flame impingement, hot spots, scaling, and decarburization.
- Excellent turndown characteristics.
- Step design of burners provides flow barrier to protect from overheating.
- Models to fit most applications in ratings from 250,000 to 2,500,000 BTU/hr (63,000 to 630,000 kcal/hr).
- Angled lighting hole provides reliable ignition facility and permits flame monitoring.
- Designed for easy on-site installation.
- Easily removable for maintenance from outside furnace.
- Rugged construction for years of trouble-free operation and low maintenance.
- Quiet operation.