WCA May 2014

Technology news

New directly heated furnaces ❍ One of the new furmnaces from Wire Körner

temperature is adjusted with a precision of ±2°C. A central recuperator installed in the waste gas duct preheats the combustion air for the high-speed burners to 200-250°C, while reducing the waste gas temperature at the stack from 600°C to 400-500°C. Already in the preheating zone Wire Körner exploits the thermal energy of the waste gas to heat up the wire entering the furnace. This reduces the energy demand for preheating. In contrast to previously used burners, the high-speed burners employed by Wire Körner can be adjusted in several steps. This ensures that the burners consume exactly the amount of energy they need, not more. The company has brought down heat losses via the furnace wall by optimising the layout of the wall, by insulating ceramic fibres. An additional coating ensures a long service life of the furnace wall even under conditions of high CO contents and high flow velocities. An additional, 2.5cm-thick Microtherm ® insulating layer behind the refractory brick lining brings down heat losses even further. The furnace is directly heated. The heat is transferred into the wire by convection, at flow velocities of up to 120m/s. This provides much better energy efficiency than heating by radiation.

WIRE Körner has launched a new series of directly heated patenting furnaces fitted with automatic furnace atmosphere control and burner with heat recuperation. With these new energy-saving furnaces, the company is further expanding its range of efficient and eco-friendly heat treatment plants for wire. Based on his good experience with the furnace, a German customer has already ordered an extension to his existing unit. The first unit of this new furnace generation has been in operation for two years. Designed for a throughput of 2,000t per hour, it processes wire in diameters from 1.5 to 5.5mm. The plant expansion was commissioned in April. By implementing a wide array of innovative features, Wire Körner has increased the efficiency of patenting furnaces for wire and achieved savings on energy consumption of some eight to ten per cent compared to conventional furnaces. The very first furnace of this new generation has already been in production for more than two years. With an innovative sensor, Wire Körner has realised a system for controlling the furnace atmosphere. Via the furnace control system the air/combustion gas ratio is set exactly within a specified range. The high control precision and stability of the gas/air ratio makes the new furnaces superior to pre mix systems. In addition to the savings on energy, controlling the air/gas ratio keeps NOx emissions low and prevents decarburisation of the wire. The furnace

Wire Körner GmbH – Germany Website : www.wirekoerner.com

29

www.read-wca.com

Wire & Cable ASIA – May/June 2014