The advancement in industrial heating systems has led to the widespread adoption of silicon carbide burner nozzles. These nozzles, now a cornerstone of modern kilns and furnaces, exhibit exceptional control and offer improved temperature uniformity.

How Silicon Carbide Burner Nozzles Work

Silicon carbide burner nozzles function by forming a chamber where the majority of the combustion process occurs. This design reduces the amount of flame exposed directly to the kiln load, mitigating the occurrence of radiant hot spots. The tapered exit of the tube enables an increase in exhaust velocities, which enhances the mixing within the kiln and promotes temperature uniformity. The higher velocities also boost the entrainment of the kiln atmosphere around the burner, diluting the hot exhaust stream and facilitating rapid energy transfer.

Advantages of Silicon Carbide Burner Nozzles

The benefits of using silicon carbide burner nozzles are manifold. These nozzles are manufactured from high-quality materials, ensuring a long service life. Their low thermal expansion and high conductivity attributes provide remarkable resistance to thermal shock cracking. The dimensional stability of these nozzles prevents significant deformation and creep, and they showcase excellent resistance to oxidation and corrosion. The lack of need for a burner quarl, their suitability for brick or fibre linings, and applicability in most types of kilns – tunnel, roller and shuttle – make them a preferred choice. Furthermore, silicon carbide, or SiSiC, is recommended for most kilns and furnaces working below 1350°C, but options like ReSiC material are available for higher temperature applications.

The Role of 3D Printing in Enhancing Silicon Carbide Burner Nozzles

The advent of 3D printing technology, specifically the Amasic-3D® additive manufacturing method, has revolutionized the realm of silicon carbide burner nozzles. This technology enables the creation of novel burner nozzle configurations and innovative designs that amplify performance and prolong service life. This evolution in manufacturing translates into an expanded range of industrial and domestic oil or wood pellet boiler burners available for direct heating.

Manufacturing Process of Silicon Carbide Burner Nozzles

The manufacturing process of silicon carbide for burner nozzles involves multiple steps that transform the raw materials into a high-quality, durable product. The silicon carbide parts are initially shaped by extrusion or cold isostatic pressing. Following this, they undergo machining before they are sintered under vacuum at very high temperatures. This process imbues the silicon carbide with its ultimate corrosion resistance, extreme hardness, and excellent mechanical properties.

The manufacturing process involves:

1. Powder preparation: Silica sand and carbon are combined in an Acheson graphite electric resistance furnace at high temperatures, producing silicon carbide. The resulting “stones” and grains are then crushed into a fine powder and purified with halogens.
2. Kneading: The fine powder is homogeneously mixed with non-oxide sintering aids to form a paste.
3. Shape forming: The pasty mixture is compacted and shaped either by extrusion or by cold isostatic pressing. Extrusion is used for producing silicon carbide tubes, while cold isostatic pressing is used for manufacturing silicon carbide plates andblocks.
4. CNC Machining: The surfaces of the plates are machined, and holes are drilled on the process and services sides in the cylindrical blocks using CNC machining. The very low mechanical strength of the green material demands special care during this process.
5. Sintering: The material is sintered in an inert atmosphere at temperatures up to 2300°C. During sintering, the products shrink isostatically by approximately 20%.
6. Lapping or grinding: If needed, the sintered silicon carbide parts can be machined to precise tolerances using precision diamond grinding or lapping techniques.
7. Quality check: The finished silicon carbide parts undergo a series of dimensional checks, tests, and inspections. The mechanical properties are also carefully checked and monitored after each production batch.

Conclusion

Silicon carbide burner nozzles, bolstered by cutting-edge manufacturing processes, have proven to be an indispensable component in modern heating systems. Their outstanding properties and the benefits they confer—ranging from improved temperature control to extended service life—make them a pivotal advancement in the ceramics industry.