JPS5844694A - Induction furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention relates to improvements in induction furnaces.

Maximum grain size 3 to 5 made of a mixture of lumina, silicon carbide, etc.
An irregularly shaped refractory material of about trL/m is stamped and sintered to form the furnace wall of the melting furnace body, and an induction heating coil with a water cooling pipe etc. attached to the outer periphery of the furnace wall. It is well known that the material is constructed by wrapping the material.

However, in the above-mentioned conventional induction furnace, when zinc Zn, which has a low boiling point of about 906°C, is melted at about 920°C as the metal to be melted, the Zn vapor penetrates the furnace wall. This may cause cracks in the furnace wall, and the steam may reach the induction heating coil and degrade the electrical insulation of the coil, or cause the coil to burn out. However, there was a problem in that the metal vapor leaked through the furnace wall into the cooling pipe side, resulting in considerable wasted power for induction heating.

This invention was made to solve the various problems mentioned above, and instead of the furnace wall made of amorphous refractory material, a shaped crucible made of natural silica is used, and the outer peripheral surface is surrounded by the outer periphery of the wall. An air layer is provided, and an induction heating coil is wound around the outer periphery of the air layer via a heat insulating wall made of a refractory material to reduce the penetration rate of molten metal vapor into the furnace wall, and The air layer prevents metal vapor from adhering to the induction heating coil, prevents the coil from burning out, and prevents the induction heat generated in the crucible from dissipating to the induction heating coil, improving thermal efficiency. The purpose of this invention is to provide an induction furnace with good quality.

Next, one embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, 1 is a crucible for dissolving zinc Zn, for example, and this crucible 1 is formed using natural silica 5i02 to have a circular cross-sectional shape and a substantially U-shaped vertical cross-sectional shape. It is shaped and sintered appropriately using a known method.

The crucible 1 is placed on a base 2 made of firebrick or the like, and the crucible 1 is placed on the outer periphery of the crucible 1 at an appropriate distance from the outer peripheral surface 1a. A heat insulating wall 3 made of a fireproof material is provided surrounding the outer peripheral surface 1a. In this way, an air layer 4 is formed between the outer peripheral surface 1a of the crucible 1 and the inner peripheral surface 3b of the heat insulating wall 3. This air layer 4 is provided with two openings 4c, 4c at appropriate positions, for example, at positions on the bottom side of the crucible 1, which communicate with the external space of the induction furnace.

An induction heating coil 5,
A yoke 6 is provided so as to surround these induction heating coils 5 .

Furthermore, this yoke 6 is fixed to a frame 7 with bolts and nuts (not shown).

In the induction furnace configured as described above, even if the metal to be melted is, for example, zinc Zn with a low boiling point of 906°C and the Zn is melted at about 920°C, the crucible 1 is made of natural silica. The porosity of the crucible 1 is reduced to about 1, compared to the conventional type stamped with refractory material.
/2 and its air permeability to about 1730, it is possible to greatly suppress the penetration of Zn vapor into the crucible 1. Therefore, the amount of induced heat generated in the metal within the crucible 1 that is conducted through the crucible 1 can be effectively suppressed.

In addition, compared to the conventional method of stamping and building a furnace by stamping an irregularly shaped support material in an induction furnace, in this invention, a pre-shaped crucible 1 is made outside the induction furnace, and this shaped crucible 1 is placed inside the induction furnace. Since the crucible is mounted, the air layer 4 can be easily formed around the outer periphery of the crucible.

Furthermore, the vapor leaked into the air layer 4 through the crucible 1 is cooled by the air present in the air layer 4 and liquefied,
It is discharged to the outside of the induction furnace through the opening 4C as shown by the arrow in FIG. In this way, even if the metal vapor in the crucible 1 slightly leaks through the crucible 1, the insulating wall 3 and the induction heating coil 5 are shielded from this high-temperature leaked metal vapor by the air in the air layer 4. , i Prevent the induction heating coil 5 from deteriorating its electrical insulation or burning out.
It can definitely be prevented. -Furthermore, the amount of heat dissipated from the induction heat generated in the crucible 1 and leaking out of the induction furnace through the crucible 1 is effectively suppressed by the air layer 4 and the heat insulating wall 3.

The induction heating coil 5 can control the heating
By increasing the utilization rate of the heat generated in the metal in the metal, that is, the thermal efficiency, the power consumption required for induction heating can be reduced and saved.

The air layer 4 is provided with intake ports 8, 8 at appropriate positions, for example, at the bottom of the crucible 1, as shown in FIG. An exhaust port (not shown) is provided at the position, and these air intake ports 8
, suitably cooled fresh air may be circulated into the air layer 4 via an exhaust port. Alternatively, the exhaust port may be provided at a corresponding position on the bottom of the crucible 1. In this way, the above-mentioned air layer 4 can shield the metal vapor from the heat insulating wall 3 and the induction heating coil 5, and the amount of induced heat generated in the metal inside the roof 1 can be prevented from flowing to the outside. The leak prevention effect can be made even more effective.

As is clear from the above explanation, according to the present invention, an air layer is provided between a regular crucible made of natural silica and an insulating wall and an induction heating coil provided around the outer periphery of the furnace wall. , the metal vapor power 2 melted by induction heating in the crucible is effectively suppressed from leaking through the crucible, and even if the metal vapor leaks out of the crucible, the air layer prevents the heat insulating wall and the induction It effectively prevents leakage to the heating coil, reliably prevents electrical insulation deterioration of the induction heating coil and its burnout, and also suppresses heat dissipation of induction heat to increase thermal efficiency. There is an excellent advantage that power consumption required for heating can be saved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of an induction furnace according to an embodiment of the present invention;
FIG. 2 is a sectional view of a main part of an induction furnace according to another embodiment of the present invention. 1... Crucible, 1a... Ru, 2 Outer peripheral surface of crucible, 2...
・Base, 3...Insulating wall, 4...Air layer, 4C...
Opening, 5... Induction heating coil, 6... Yoke, 7...
・Frame body, 8...Intake port. Patent applicant: Fuji Electric Manufacturing Co., Ltd. Representative Patent Attorney Aoyama, 2 people

Claims (2)

[Claims] (1) An air layer is formed around the outer periphery of a regular crucible made of natural silica, and an induction heating coil is wrapped around the outer periphery of the air layer via an insulating wall made of refractory material. An induction furnace characterized by comprising: (2) The air layer is provided with an intake port and an exhaust port to circulate fresh air sucked from outside the induction furnace into the air layer. induction furnace.