A patented solution.


EBNER.blog | Liu Ning, EED, China

A patented solution.

EED develops an electric-heated horizontal cylinder annealing furnace for Yantei Fisend.

Yantai Fisend Bimetal Co., Ltd. is a manufacturer of copper and aluminum composite materials, with their products mainly finding use in the power transmission industry.

Yantai Fisend recently began a search for additional annealing capacity, with strict performance specifications. After products are rolled, they require bright annealing at a temperature of 320 °C. The surface must remain free of damage and scratches, before the annealed product is removed at a temperature below 55 °C. Furnace capacity was specified as 6 t. Typical products such as wire and busbar material can be seen on the right.

In the search for solutions, we first considered a bell annealer. To increase the output of the furnace, we proposed that the charged copper coils be tilted and placed on the workbase with coil carriers. However, tilting loose copper coils does not guarantee that the surface of the strip will remain undamaged. Furthermore, if this charging method was adopted by the customer, the load-ing capacity would be very low. Much of the workload space would remain empty, preventing the requested throughput capacity from being met.

The next solution that was considered was a batch-type (chamber) furnace. There would be no need to tilt the copper strip, which could be charged directly into the furnace – and the throughput capacity would meet the customer’s requirements. However, the batch furnace solution would use nitrogen as a process atmosphere. This would mean that the oxygen content in the furnace would not be less than 2000 ppm, and a bright surface on the annealed product could not be ensured. Furthermore, the cooling rate in such furnaces is low during the cooling phase, and it would have been impossible to achieve the outlet temperature of 55 °C or less that had been speci-fied by the customer.

EED‘s designers thus turned to a new solution: they envisioned a “horizontal bell annealer” for bright anneal-ing, combining the advantages of both a bell annealer and a batch-type/chamber furnace. This unique design has since been patented.

Typical products such as wire and material for busbars

After several rounds of discussion and adaptation, EED‘s horizontal cylinder annealing furnace finally took shape.

The furnace consists of the following main parts:

  • Heating cover: electric heating system, external connection to cooling blower
  • Furnace door with diffuser
  • Internal cover: circulation unit, heat exchanger and direct nitrogen cooling

In the cooling stage, nitrogen is drawn out of the furnace by the blower, cooled at the heat exchanger and then circulated back into the furnace.
Two views of the equipment, taken during assembly, can be seen below.
As of this writing, the furnace has been packed and is ready to be delivered to customer for installation and commissioning. We would like to thank Yantai Fisend Bimetal Co., Ltd. for the order, and for their support during development of this innovative solution.

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