The process of "indirect heating", using radiant and flame tubes, transfers heat by radiation. Moreover, the combustion gases are not permitted to come into contact with the product being fired.
Our CarSIK therefore fully satisfies the extreme demands made on material for radiant tube applications. For reasons of energy conservation, as an alternative to a central recuperator, the combustion gases can be transferred through a recuperative burner, incorporated in the radiant tube, which functions on a countercurrent basis. The high degree of preheating of the combustion air, which results from this principle of operation, ensures optimum efficiency.
There has been significant technological progress over the past few years due to the use of silicon-infiltrated, reaction-bonded SiC(RBSiC). One important advantage offered by this material is the increase in the specific radiation capacity at the high kiln temperatures. For example, assuming a radiant tube of identical dimensions operating at 1100°C, RBSiC achieves a heat transfer of more than double that of CrNi steel (please refer to photo). In the area of indirect heating, CarSIK products cover a wide spectrum of temperature and service conditions.
When compared with high alloy steels, these products exhibit no deformation in service, thereby making the components free of any maintenance. CarSIK radiant and flame tubes have been used successfully together with recuperative burners in a wide range of heat treatment processes by almost all system constructors worldwide for many years.
An increasing degree of automation is making greater demands on the ceramic burner components. By direct communication with constructors and end-users, Schunk Ingenieurkeramik GmbH can develop specific solutions to each individual customer up to the production stage.
Various forming processes are available depending on the different shape geometry's required. The main process used is slip casting, which enables production of complex shapes while at the same time keeping tight dimensional tolerances. This type of production can be adopted from prototype up to high volume manufacture.
- No porosity, therefore excellent oxidation and corrosion resistance
- Very good thermal shock resistance
- Stability of shape up to maximum operating temperature (high degree of creep resistance, no blending of tubes in service meaning much reduced maintenance)
- Gas tight
- Very good thermal conductivity (increased radiative heat transfer)
- Low mass
- High degree of reliability and economy in service
- Optimum efficiency