JPS6038879Y2 - induction furnace - Google Patents

Description

[Detailed description of the invention] This invention relates to a device for preventing a part of the magnetic flux generated by a heating coil from leaking through a bottom plate made of magnetic material. The aim is to reduce

Examples illustrating the present invention will be described in detail below.

The drawing shows a crucible-shaped induction furnace. In the drawing, 1 is the lining material forming the crucible, 2 is the molten metal, and 3 is the lining material 1.
4 is a coil cement coated between the lining material 1 and the heating coil 3; 5 is a plurality of coil cements placed on the outside of the lining material 1 and spaced at equal intervals around the lining material 1; The disposed iron core forms a magnetic flux path outside the coil for the magnetic flux generated by the heating coil.

6 is a refractory that receives the lining material 1 from below, 7 is a heat insulating material provided between the refractory 6 and the bottom plate 8, and 9 is a shield provided between the bottom plate 8 and the heat insulating material 7, superimposed on the bottom plate 8. The plate is non-magnetic, such as a copper plate or an aluminum plate.
It is also made of a highly conductive material.

10 is a side furnace frame; 11 is an upper furnace frame; side furnace frame 10;
are connected to each other by bolts 12, and a refractory material 13 is packed inside, which supports the upper part of the lining material 1 from the sides and at the same time presses down the upper end of the heating coil 3.

In the above configuration, by supplying AC power to the heating coil 3, heat is generated between the secondary conductor and the material to be melted in the crucible, and this heat melts the material to be melted. In the case where 9 is not provided, that is, in a conventional induction furnace without shield plate 9, most of the magnetic flux generated by heating coil 3 passes through iron core 5.

However, a part of the magnetic flux does not directly enter the iron core, but becomes leakage magnetic flux and penetrates the bottom plate 8 made of a magnetic material.

For this reason, leakage magnetic flux penetrating the bottom plate 8 causes eddy currents in the bottom plate, which is one of the causes of power loss.

On the other hand, in this case, as mentioned above, a non-magnetic and conductive shield plate 9 is interposed on the bottom plate 8, so this part can block the magnetic flux toward the bottom plate 8, and the shield Even if an eddy current is generated in the plate 9 itself, since the shield plate is made of a highly conductive material, it generates little heat, and therefore power loss due to such leakage magnetic flux can be reduced as much as possible.

[Brief explanation of the drawing]

The drawings show an example of the present invention; Figure 1 is a sectional view, Figure 2 is a sectional view,
The figure is a plan view of a half part. 5...Iron core, 8...Bottom plate, 9...
・Shield plate.

Claims (1)

[Scope of utility model registration request] An induction furnace characterized in that a shield plate made of a non-magnetic and highly conductive material is interposed between a bottom plate made of a magnetic material and an iron core.