Drum walk-through electric furnace

Drum furnaces are called, through the heating chamber of which a rotating muffle (drum) passes. The heating chamber and the drum are located at a slight angle to the horizon, so that during rotation, the material in the drum moves from the loading opening to the unloading opening, while being heated.

In electric drum furnaces, many heat treatment processes of bulk materials or small cylindrical workpieces can be carried out: drying, roasting, calcining, quenching (for example, shot) and tempering.

Most of the rotary kilns are continuous and have loading devices, funnels for unloading. Calcining furnaces are often equipped with cooling modules. Modules can be air or water cooled. The straight-through principle of operation is convenient for integration into technological lines. In the process of heating, chemicals evaporate and sublimate for the removal of which supply and outlet branch pipes are provided (purge) .

Drum Electric Furnace Design

The electric furnace consists of a support frame, on which a heating chamber is installed and a support for the drum, so that the axis of the furnace and the drum are aligned. The very same support frame is installed on special racks, with the ability to change the angle of inclination of the support frame. The frame is permanently supported on the front support and fixed at the desired angle in the rear support.

The heating chamber consists of a body (directly the chamber itself) and a removable vault. The heating chamber and the roof consist of a welded frame lined with fibrous thermal insulation from the inside. There is a hole along the axis of the chamber for the passage of the drum.

Structurally, the heating system of the electric furnace is divided into several independently controlled temperature zones.

The kiln drum is made by rolling a heat-resistant steel sheet into a cylinder. The required length is obtained by welding the pipes at the ends. Butt welds are reinforced with overlays. The surfaces for mating with the end boxes are mechanically processed. The central part of the drum is located in the heating chamber, where heating takes place directly. Outside the heating chamber, support rims are put on the drum for rolling. The rims are installed on support rollers, and on one side there are additionally thrust rollers that do not allow the drum to shift axially. The drum can be rotated from an electric drive through a chain or gear drive.

Heating furnace and material in the drum it is produced by electric heaters in the form of spirals or zigzags. Heaters are located on the side and bottom walls. Heaters are switched into groups outside the frame in special air ducts, and are controlled by a signal from thermocouples brought close to the drum in the area where the material is located.

As an option, a loading box is offered, which is installed on the frame and mates axially with the drum through flexible seals. The box has a hopper or an opening for the chute of the auger or conveyor feeder. Also, a branch pipe for exhausting purge air is removed from the box.

Main technical characteristics