The proposed electric resistance furnaces are designed for heat treatment up to 1000 ° C of steel details – tempering, normalization, heating prior to plastic deformation and others.
The bell-type furnace consists of two parts – a stationary base and a removable cap. The details that will be heat treated shall be placed on the stationary base when the cap is placed on a special stand.
The casing is made of sheet and structural steel.
The thermal insulation of the stationary base and the movable cap is made of chemically neutral and resistant to various gas environments light-weight refractory bricks, rigs, vacuum formed refractory elements, mats and protective coatings.
The metal structure of the stationary base is made of profiled and sheet steel. There are relevant guideways for exactly fixing the cap when placed on the base. On the thermal insulation are installed shaped bodies made of fireproof steel on which the payload is loaded.
The movement of the cap is carried by an overhead crane.
The power supply of heating elements of the cap is implemented by special contact blocks.
The working space of the furnace is divided into heat zones. Each is equipped with an independently operating temperature controlling system.
The heating elements made of new high quality resistance alloys, are arranged appropriately in the heat zones.
The temperature in the heating zone of the furnace is regulated by PID microprocessor-based programmable temperature regulators, perceiving direct signal from standard thermocouples.
Electrical switchboards are designed for power and control of the furnace with operating voltage according to the design and the control of the thermal processes. The electrical switchboards provide appropriate control and protection of the circuits and automation, providing the required security.
The electrical resistance furnaces and respectively the switchboards for powering and management work with three-phase mains voltage (380 V) – to power the load chain and 250 V for control circuits (command and protective circuits related to the safety).
Available furnaces of this type are made in accordance with the technical assignment of the client and in accordance with the requirements of the technology for heat treatment of the products.