JPH017994Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an induction melting furnace, and particularly to an improvement in the magnetic shielding structure of a power supply window provided in a furnace frame.

In general, an induction melting furnace has a melting chamber made of a refractory material, and an induction coil made of a water-cooled copper tube wound around the outer periphery of the melting chamber.A plurality of return path iron cores are arranged radially around the outer periphery of the induction coil. An iron furnace frame is provided to surround these furnace structures, and a connection conductor for connecting the induction coil and the external water cooling lead passes through a power supply window opened in the furnace frame.

Since this connecting conductor conducts alternating current, leakage magnetic flux generated from the connecting conductor overheats the vicinity of the power supply window of the furnace frame through which this connecting conductor passes. If the induction melting furnace is powered by normal power, the temperature rise in the furnace frame due to induction heating can be kept low by opening the power supply window wide and keeping a sufficiently large distance between it and the connecting conductor.

However, in recent years, as induction melting furnaces have become more powerful and more compact, the amount of power they supply has increased, resulting in more leakage magnetic flux, and the number of return path cores placed around the outer circumference of the induction coil has also increased. Become,
It is not possible to form a power supply window with a wide opening area in the furnace frame. Therefore, despite the increase in leakage magnetic flux,
The distance between the connecting conductor and the power supply window becomes narrow, and overheating of the furnace frame near the power supply window is unavoidable, resulting in a disadvantage that power loss in this area becomes large.

The purpose of the present invention is to provide an induction melting furnace that eliminates the above-mentioned drawbacks, prevents overheating of the furnace frame due to leakage magnetic flux from connected conductors, reduces power loss, and saves energy. .

An embodiment of the present invention will be described in detail below with reference to the drawings.

1 to 3 show an embodiment of the present invention applied to a crucible-type induction melting furnace.

In the figure, reference numeral 1 denotes a melting chamber made of refractory material, and a sprue 2 is provided in the upper part of the melting chamber 1, and a molten metal 3 is melted and held inside. An induction coil 5 formed by winding a water-cooled copper tube is provided on the outer periphery of the melting chamber 1 with a coil cement 4 interposed therebetween. A plurality of return path iron cores 6 are arranged radially around the outer periphery of the induction coil 5, and these furnace body structural materials are composed of a furnace bottom refractory material 7.
and is surrounded by an iron furnace frame 8.

A rectangular power supply window 9 is formed on the side of the furnace frame 8 opposite to the sprue 2. As shown in FIG. 3, a magnetic shield plate 10 made of a copper plate, an aluminum plate, or the like is provided in the shape of a furnace at the inner peripheral edge of the power supply window 9. As shown in FIG.
This magnetic shield plate 10 has flange portions 11 and 11, respectively.
A square-shaped upper shield member 12a and a square-shaped lower shield member 12b are combined to face each other, and a gap is provided between them to form a discontinuous frame shape. Water cooling pipes 13a and 13b made of metal pipes are provided in close contact with each other inside the upper shield member 12a and the lower shield member 12b, and one of the opposing parts is connected with a rubber hose 14 to form a continuous water passage. has been done.

15 is a water cooling lead installed outside the furnace body,
It is made of a flexible conductor in order to tilt the furnace body when tapping the molten metal 3. The water cooling lead 15 and the induction coil 5 are connected by a connecting conductor 16 passing through a power supply window 9 provided with a frame-shaped magnetic shield plate 10, and AC power is supplied to the induction coil from the water cooling lead 15 through the connecting conductor 16. 5 is energized.

In the induction melting furnace having the above structure, leakage magnetic flux generated when alternating current is passed through the connection conductor 16 is shielded by a magnetic shield plate 10 provided at the inner periphery of the power supply window 9, and the iron furnace frame 8 Since leakage to the furnace frame 8 is prevented, overheating in the vicinity of the opening of the power supply window 9 of the furnace frame 8 can be prevented. Further, since the magnetic shield plate 10 is overheated due to eddy current loss, it is cooled by water cooling pipes 13a and 13b placed inside to suppress the temperature rise. in this case,
The magnetic shield plate 10 has an upper shield plate 12a and a lower shield plate 12b separated from each other and discontinuously assembled, and at the same time, the water cooling pipes 13a and 13b provided inside these plates are connected by a rubber hose 14 having electrical insulation properties. This can prevent generation of circulating current and further reduce power loss.
As a result, the power loss in the vicinity of the power supply window 9 was able to be reduced by more than 50% compared to the conventional structure in which the magnetic shield plate 10 is not provided.

As explained above, according to the present invention, even when the leakage magnetic flux from the connecting conductor is large and the opening area of the power supply window is small, overheating of the furnace frame due to the leakage magnetic flux is prevented, reducing power loss and saving. An induction melting furnace with increased energy can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of an induction melting furnace according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1 and viewed in the direction of the arrow, and Fig. 3 is a magnetic It is a perspective view showing a shield plate. 1... Melting chamber, 3... Molten metal, 5... Induction coil, 6... Return magnetic path core, 8... Furnace frame, 9... Power supply window, 10... Magnetic shield plate, 12a, 1
2b... Shield member, 13a, 13b... Water cooling pipe, 14... Rubber hose, 15... Water cooling lead,
16... Connection conductor.

Claims (1)

[Scope of utility model registration request] A melting chamber made of a refractory material, an induction coil provided on the outer periphery of the melting chamber, a plurality of return path iron cores provided radially around the outer periphery, and an iron furnace frame surrounding these furnace structures. In an induction melting furnace comprising a connecting conductor that penetrates through a power supply window opened in the furnace frame and connects the induction coil and an external water cooling lead, a magnetic shield is provided discontinuously on the inner peripheral edge of the power supply window. An induction melting furnace comprising: a plate; and a water-cooled tube attached to the magnetic shield plate.