Holding Furnaces

Holding and storage furnaces are used in continuous and discontinuous melting operations. Unpredictable disruptions can occur in continuous casting operations, so holding and storage furnaces are also used as “buffers” there.

In discontinuous melting plants, holding and storage furnaces ensure the availability of ready-to-cast metal in sufficient quantities and at a constant metal temperature.

The holding furnace shown here was planned, manufactured, assembled and commissioned by Tegisa GmbH in 2019 and handed over to the customer for production.

The holding furnace is used to hold a quantity of liquid metal from various melting furnaces and to fill more than 10 casting furnaces. In order to reach these casting furnaces, the holding furnace is designed to be mobile and stands on an 80 meter long driveway. At the end of the driveway there is the furnace park position, in which there is safe access for maintenance and cleaning work. The usable quantity in the casting operation is 3.5 t and the connected load is 275 kVA.

The holding furnace is pressure-tight and designed as a siphon for metered filling of the casting furnace. The filling siphon picks up the liquid metal from the tiltable melting furnaces, the melt reaches the forehearth from the pressurized furnace chamber via the casting siphon and is dosed into the casting furnace with a pneumatically operated plug control. The metal bath level in the forehearth is kept constant by means of pressure control. Load cells between the furnace and the trolley measure the weight difference for actuating the stopper control.

The holding furnace is moved with electric drives and, in automatic mode, achieves a positioning accuracy of ± 1 mm over the entire distance of 80 meters. All assemblies such as power cabinets, control cabinet, pressure control and gas burner station that have to be positioned close to the furnace are placed on the trolley. Media such as natural gas, nitrogen, compressed air and cooling water are fed to the kiln carriage with an energy chain (media drag chain).

The power connections for the power and control components are made via traveling double pantographs that sit on permanently installed sliding contact rails. In addition to the sliding contact rails, a WLAN communication system, a redundant position measuring system and a position-independent extraction system are also installed along the route.

When changing the inductor or when emptying the melt, the furnace vessel can be tilted hydraulically up to 95 degrees.