Continuous furnaces are mainly used for high quantities and special requirements for reproducible results. The application range of continuous furnaces is extremely diverse. A distinction is made here between numerous different applications in which the products to be heat-treated are subjected to specific temperatures depending on requirements. This refers not only to the applied temperature or complex temperature profiles, but also to different types of flow. Of particular note here are horizontal and vertical air guidance flows, as well as direct air guidance systems via, for example, high-performance nozzles for particularly effective heating.
Further differences exist in the continuous, discontinuous or quasi-continuous conveying of the products. The latter represents a fixed cycle which automatically conveys the products forward. The advantage of discontinuous and quasi-continuous conveyance is the option of using lift gates as these significantly increase the energy efficiency of the systems by minimising heat loss to the outside. It is also possible to regulate the circulating air volume automatically, for example via frequency converters, to further reduce the amount of air escaping. Even in continuous processes, it is possible to reduce these losses to a minimum using curtains or clever air routing.
The entire conveyor technology can generally be planned, engineered and manufactured by us at the Rhede site. Here we offer a wide range of conveying techniques and custom solutions (LINK). This also includes safety technology such as protective fences and light barriers, as well as complete commissioning and safety-related interlinking of the overall plant (LINK).
A wide variety of materials (such as steel, aluminium, plastics, rubber, silicone, carbon, composites, composite materials, glass, ceramics etc.) are treated in the continuous furnace in their various, sometimes complex, component geometries with parameters specific to the product. In addition, depending on the product requirements and cycle times of the continuous furnace, there are further parameters to be considered or met, such as heating and cooling rates, temperature homogeneity, the safe handling of any combustible materials escaping from the product and the measurement, recording and documentation of the process. Where required, we also pay particular attention to compliance with DIN EN ISO 1539 for combustible materials when designing continuous furnaces. At Airtec, the focus is always on implementing the specific and necessary process and customer requirements.
This means that continuous furnaces can also be equipped with different types of heating, depending on customer requirements. These include electricity, gas, infrared or even oil and steam.
Example of an Airtec AHT 250-ek continuous furnace: In the furnace shown above, the products (in this case, stators, as an example) are suspended from the overhead conveyor. These are then automatically soaked in resin and then dried in the furnace.
Example of an Airtec AHT 4000-ek continuous furnace: In the furnace shown above with a total length of approx. 25 m, powder-coated components are dried with three tempering zones. In the first zone, the powder is supplied via an infrared field. The components are dried in the second zone and cooled down again in the third zone.