MELTING FURNACE

The furnace is designed for metals with suitable melting temperature in a volume of 10 cm³. It is an electrical transformer, the secondary winding ends of which are closed with a conductive vessel in which melting occurs. Oven can be used for artistic casting, in jewelry, for casting billets, alloys.

For the manufacture of furnace required U-shaped electromagnetic core 1 (Fig.1), recruited from the plates of transformer steel with a cross-section of 100 cm². The primary winding 2 consists of 80 turns of copper wire with a diameter of 4 mm. the Secondary winding 3 consists of one coil and made of copper plates by section 150×5 mm. because of the scarcity of plates of this size the secondary winding can be made of several parallel coils, using for their manufacture copper wire (large diameter wires from the cable tram trolley, etc.). The primary winding is fabricated on an insulating frame, which is performed after Assembly of the electromagnetic core. Each element 3 is attached to a secondary winding configuration, is shown in bold line, the dimensions of which are consistent with the cross section of the electromagnetic core, 4 metal bars, with the length of the crucible, followed by encompassing them sasayakana part of the magnetic circuit. The ends of the elements pulled together a massive metal bars, the heat capacity which prevents overheating of the secondary winding from the crucible. Metal bars 4 are attached to the furnace casing 5, made of angle iron, through the insulating strip.

The device of the crucible

Inside the metal casing of cylindrical shape 2 (see Fig.2) is placed in Cup 1, made of metal, which has a melting point higher than that of molten metal.

Fig. 1. Table foundry:

1 – magnetic core; 2 – primary winding; 3 – secondary; 4 – metal contact bars; 5 – furnace casing; 6 – handle; 7 – the crucible

Fig. 2. Crucible furnace:

1 – vessel (iron glass); 2 – body; 3 – thermo-filler (sand-clay mixture)

For melting of copper and alloys containing copper, Cup is made of cast iron. The space between it and the casing is filled with sand-clay mixture 3, which hardens after a few heats. To the surface of the cylindrical housing is attached to the handle (figure 2 conventionally not shown).

After filling the crucible with scrap metal crucible is placed between the metal bars, as shown in figure 1. The characteristic buzz of the windings of the furnace is determined by the presence of electrical contact between the crucible and metal bars. If no contact, then you need the handle of the crucible to move before the advent of buzz. The observation of the melting process is carried through the gap between the metal bars and frame of the furnace.

The capacity of the furnace under the above parameters when included in mains voltage of 220 V, 6 kW. Electrical wiring in the apartment, kitchen supply outlet of the electric furnace, allows connection of the receiver of such power.

G. MAKARYCHEV, Prokopievsk, Kemerovo region.