ALUMINIUM COIL/FOIL ANNEALING FURNACES
Wesman has a full range of Aluminium Coil/Foil Annealing Furnaces up to a capacity of 80 MT batch to offer to the aluminium industries. These furnaces will be Electrically Heated or Gas Fired and the design will be either Fixed Hearth or Bogie Hearth type to suit customer’s requirement. Aluminium coils/foils placed on the charge carrier can be loaded into the fixed hearth furnace by a hydraulically/electro-mechanically driven charging machine or can be loaded on the bogie with the help of an EOT crane for bogie hearth furnace. After the annealing cycle is completed the foils/coils are discharged from the furnace with the help of discharging machine from the fixed hearth furnace or unloaded from the bogie hearth furnace with the help of the EOT crane.
The foils/coils will be indirectly heated through radiant tube burners located behind stainless steel baffles and are provided with suitable recirculation fans for better heat transfer through convection and good temperature uniformity.
Hot air recirculation inside the furnace is done by efficient axial or centrifugal type recirculation fan, which can be with a two-speed motor or with the VVF drive for low power consumption. Stainless steel baffle for proper hot air circulation inside the furnace is provided. Forced air-cooling arrangement with the help of centrifugal fan can be offered.
The furnace can also be provided with facilities for introducing protective atmosphere like nitrogen gas while carrying out foils/coils annealing.
The furnaces are fired with Wesman’s high efficiency (radiant tube) gas burners which will be suitable for controlled mixing thus providing highly radiant flame, distributing heat release along the entire length of the radiant tube, supported by a full complement of combustion system consisting of combustion fan and gas trains. In addition auto ignition, flame failure safety and complete control systems are offered. Gaseous fuel such as LPG or Natural Gas can be used.
For customers preferring electrical heating, the furnace can be provided with electrical heating through vertically suspended heater cartridges located along with the sidewalls of the furnace. The heating elements of the furnace are suitably divided into a number of heating zones with each zone of having their bank of heater cartridges. Each bank heater cartridges shall be connected either in STAR/DELTA or Parallel STAR/DELTA groups to have minimum number of heater cartridges per phase per group so that the heater cartridges of groups can be isolated and replaced without switching off the whole furnace.
The furnaces can be of Double Wall construction with inner SS 304 and outer MS packed in between with Ceramic Fiber Lining at the side walls roof and door to reduce heat losses to economic minimum. The bottom hearth of the furnace will be provided with combination of medium grade alumina bricks backed by insulation bricks to minimize the skin temperature.
For electrically heated furnaces, the process control shall be based on heat head ratio control philosophy with thyristor heater controllers for better temperature control and energy efficiency. Wesman electrically heated furnaces can be offered with 100% thyristor controllers or 30% thyristor with 70% STAR-OFF mode for better energy efficiency during heating & soaking.