Bogie hearth furnaces

Bogie hearth furnaces

Bogie hearth furnaces with gas or electrical heating

The classical thermal treatment of large-volume, heavy parts is frequently carried out in gas-heated bogie hearth furnaces. Electrically heated plants are mostly used most in smaller areas. A bogie hearth furnace requires a particularly robust design.

Heating of steel and aluminium plates - with a bogie hearth fan furnace

The bogie hearth fan furnace is designed for heating steel and aluminium plates to temperatures between 180-630 °C. The bogie hearth is propelled by means of rack and pinion drive. The furnace door is equipped with an electromotive door traction device. The furnace is heated electrically and this is done using heating coils mounted on the furnace ceiling. The furnace heating was subdivided into three control zones, each of which has its own hot gas circulator. In addition, each control zone has its own frequency regulated cooling air fan which is switched on according to the programme. The bogie hearth furnace is dimensioned for a gross batch mass of 23,000 kg of steel components. The usable batch dimensions are 2,000 x 3,000 x 700 mm (width x length x height).

Bogie hearth furnace for soft and normal annealing

Shown here is a plant for stress free soft and normal annealing of sheet metal plates of up to 16 t. The batch dimensions are 1,500 x 5,000 x 1.000 mm (width x length x height). However since this batch size is not always available, the bogie hearth furnace can be partitioned into two independent chambers with a usable dividing wall. The plant is heated using high speed burners. Different cooling ramps can be implemented via separate cooling jets. These bogie hearth furnaces can be designed for different working temperatures.

Treatment of welded constructions, rings and rollers - with bogie hearth furnaces

The bogie hearth furnace is used for the thermal treatment of welded constructions, rings and rollers up to a maximum working temperature of 650 °C. The maximum load-bearing capacity of the bogie with an electromotive drive is 50,000 kg. The clear usable space dimensions are 2,000 x 6,000 x 1,500 mm (width x length x height). The heating of the input materials is done using eight high speed burners of 75 kW each, mounted on both sides of the lower sidewall. To attain the required cooling gradients of 80 K/h with a reference batch of 10,000 kg, additional cooling air jets were mounted next to each burner. Through these jets, extra cooling air amounting to 3,500 m³/h can be pumped into the furnace. To moderate the temperatures during the heating and cooling process, the burners are subjected to all round control.

Custom-made bogie hearth furnaces for every need

Planning and construction with the customer

Bogie hearth furnaces are also constructed in close cooperation with the customer. At the same time the plants are closely tailored to the special requirements of the application processes. Heating can be done with electric energy or natural gas/ liquefied gas as appropriate or depending on the local conditions. Many other demanding alternatives can be provided, for example multi-zone temperature regulation, forced cooling and atmospheric or pressure regulation. The structural design is based entirely on the customer’s requirements. Automatic drive via diverse supply media for the bogie hearth, the lifting door or different slides or hatches can very well be used as alternatives to the manual operations.

Optimal heat insulation for your bogie hearth furnace

The thermal insulation of bogie hearth furnaces is optimised in the same way as all other furnace types according to the user process. For processes that run for longer time, lightweight refractory bricks are used, whereas in the case of quicker processes the preferred type of furnace to be delivered is one with ceramic fibre. If the use of heavy or robust batches has to be taken into account, fireclay or refractory concrete, for example, is then used in appropriate places. A combination of different thermal insulation materials in the furnace lining rounds off the optimisation of the furnace.

Wide variety of industrial furnaces

Bogie hearth furnaces come in many different variations Simple, hall operated plants with a swing door or with a rail-bound bogie hearth, one or two lifting doors - both with or without drive respectively - forced cooling etc., are implemented in accordance with the operator’s requirements. The advantage of a bogie hearth furnace lies primarily in the simple batching of the input materials, since the bogie is in the installation room. The plant shown on the photo has two bogies driven by motors.

The bogie hearth furnace - ideal for the lower temperature range.

The main area of application of a bogie hearth furnace is in the lower temperature range, just like the chamber furnace with an air circulation fan. The heating system is mounted behind the air guiding device made of heat-resistant material. Depending on the size of the furnace, one or several appropriate radical circulating fans with relatively high static pressure are used. The air to be heated is siphoned from the furnace room and then siphoned into the furnace room again over the floor. In this way we are able to attain very good temperature distribution. The picture on the right shows two bogie hearth furnaces. The bogie hearths are placed on rails. A regulated forced cooling was also mounted.