JPS628909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating device that reduces power consumption.

A conventional induction heating device was constructed as shown in FIGS. 1 and 2. In Figure 1, 1 is a coil in which a current-carrying conductor is wound in the shape of a solenoid, 2 is a fireproof structure in which the coil 1 is buried, and a monolithic refractory such as fireproof cement is poured into the inner and outer circumferences of the coil 1. is formed. 3,3 is fireproof structure 2
A metal tube fixed to the inner circumferential surface of the refractory structure 2 and arranged parallel to the longitudinal direction of the refractory structure 2. 4 is a spacing member disposed between the metal tubes 3, 3; 5 is a fireproof member made of a material that is resistant to high temperatures and wear; and is fixed to the head of each metal tube 3, 3. A skid rail 6 is formed by the above 3, 4, and 5.
7 is an insulating member provided between the coil 1 and the fireproof structure 2. As shown in FIG. 2, this structure has a plurality of blocks connected in the longitudinal direction and installed on a refractory mount 9 connected to the coil bed 8. In this state, power is applied to the coil 1, and the upper and lower pinch rollers 10
The material to be heated 12 transferred by the drive of the coils 1 and 11 is heated by causing an induced current to flow through the material to be heated 12 by the current flowing through the coil 1.

In the induction heating device, the inner wall portion of the refractory structure 2 is subjected to thermal stress due to the radiant heat of the heated material 12 which has been heated to a high temperature and whose temperature has risen. If cracks occur in the inner wall due to this thermal stress, accidents may occur such as damage to the coil 1 due to cement etc. falling off. Whenever such an accident occurred, it was necessary to dismantle the fireproof structure 2 on the inner and outer surfaces of the coil 1 and reshape it. For this reason, as shown in Fig. 3, the inner surface of the coil 1 is left intact and the outer periphery is surrounded by a refractory structure 2, and a cylinder 13 fired to a predetermined inner and outer diameter with a refractory material is inserted into the coil 1. Therefore, methods are being considered to shorten the repair time.

On the other hand, a skid rail 6 is disposed as a means for transferring the heated material 12. Since the heated material 12 heated to a high temperature is transferred while sliding on the skid rail 6, the skid rail 6 has oxidation resistance and In order to provide abrasion resistance, a material 5 having high temperature abrasion resistance is fixed to the contact surface with the heated material 12, and cooling water is passed therethrough to protect the skid rail 6.

However, by cooling the skid rail 6, the amount of heat of the heated material 12 in contact with the skid rail 6 is absorbed, and the heated material 12 is partially cooled. For this reason, the electric power consumption of induction heating equipment (KWH/Kg:
The amount of power consumed per unit weight to raise the temperature of the material to be heated to a predetermined temperature tends to increase, and the surface temperature of the material to be heated 12 between the part in contact with the skid rail 6 and the part not in contact with it tends to increase. A temperature difference occurs. For this reason, when the material to be heated 12 was forged, there was a risk that defects would occur in the product.

In order to prevent the temperature difference mentioned above from occurring,
By forming the skid rail from a ceramic fired molded material and making it a rail that does not require cooling, it is possible to raise the temperature to the same level as the heated material 12, and it is possible to improve the basic unit as well as temperature unevenness. It is being considered.

However, since ceramic rails are formed using a firing molding method, the production of long objects with narrow cross-sections, such as rails, is subject to large distortions, bends and twists, and the accuracy of dimensions and straightness is compromised. It is extremely difficult to obtain stable quality, and it is a hard and brittle material. Therefore, fixing methods that take into account the allowance for elongation due to thermal expansion, compression or tensile loads due to frictional resistance with the heated material 12 and catching of the heated material 12 on the rail due to decrease in hardness at high temperatures, etc. In addition, abnormal stresses such as uneven loads and buckling are applied due to bending and twisting of the rails. As a result, there have been problems in that the rails may break or the material to be heated may stagnate on the rails.

For this reason, an attempt was made to omit the skid rail and move the material to be heated by sliding it directly onto the inner surface of the refractory cylinder, but the oxidized scale generated on the material to be heated would accumulate on the inner surface of the cylinder, resulting in a solid state. As the refractory melted, a chemical reaction occurred in the molten state, accelerating erosion of the inner wall of the cylinder, and abrasion of the refractory material increased significantly in a short period of time. For this reason, there was a drawback that there were problems in use.

This invention was made in order to eliminate the above-mentioned drawbacks, and includes a cylindrical member disposed inside the coil, the inner diameter of which gradually increases from one end to the other, made of a refractory material. To provide an induction heating device having at least two rail-shaped protrusions having a trapezoidal cross section in the longitudinal direction for supporting the same.

This will be explained below based on the figures. Figures 4 and 5
In the figure, 1, 7, and 12 are the same as the conventional one.
Reference numeral 14 is a cylindrical member inserted into the inside of the coil 1 and made of a refractory material formed into a predetermined shape, and is configured so that its inner diameter gradually increases from one end to the other end. Reference numerals 15 and 15 denote a pair of protrusions provided almost parallel to the cylindrical member 14, which protrude from the inner wall surface toward the center by a predetermined height, and the width of the tip part is a predetermined dimension larger than the width of the connection part with the inner wall. Small trapezoidal cylindrical member 1
4 in the longitudinal direction. 16 is a spacer provided between the coil 1 and the cylindrical member 14.

In this structure, as shown in FIG. 4, the material to be heated 12 is supported using a pair of protrusions 15, 15 formed integrally with the cylindrical member 14 as rails. As a result, the protrusions 15, 15 support the heated material 12 while being heated to approximately the same temperature as the heated material 12, thereby preventing temperature unevenness in the heated material 12. Furthermore, since a groove is formed between the protrusions 15, 15, the oxide scale generated on the heated material 12 falls into the groove and accumulates therein. For this reason, each protrusion 1
Since the upper surface of 5 is always in contact with the heated material 12, chemical reaction with oxide scale is prevented and a long life can be expected. Further, the protrusion 15 is attached to the cylindrical member 1.
Since it is molded integrally with 4, the height can be set arbitrarily. Thereby, it is also possible to design the inner diameter of the coil 1 to be smaller than the outer diameter dimension of the material to be heated 12.

The above embodiment describes the case where two protrusions supporting the heated material are provided in parallel; however, even if the number of protrusions is increased to stabilize the support of the heated material, the same effect as in the above embodiment can be obtained. You can expect. Furthermore, if a plurality of sets of protrusions are provided on the upper and lower sides or on the left and right, and the cylindrical member is rotated each time the protrusions are worn out, the replacement cycle of the cylindrical member can be further extended.

According to this invention, it is arranged inside the coil,
A cylindrical member whose inner diameter gradually increases from one end to the other is provided with at least two rail-shaped protrusions having a trapezoidal cross section in the longitudinal direction that support the material to be heated. It equalizes the temperature of the material and reduces the power consumption of the heating device.
Stagnation within the cylindrical member when the heated material is transferred can be prevented.

[Brief explanation of the drawing]

Figures 1 to 3 show conventional induction heating equipment.
The figure is a front view, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG. 3 is a sectional view. Figures 4 and 5 show an embodiment of the invention, with Figure 4 being a side view;
FIG. 5 is a sectional view taken along the - line in FIG. 4. In the figure, 1 is a coil, 12 is a heated material, 14 is a cylindrical member, and 15 is a protrusion. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] 1. In a cylindrical member made of a refractory material placed inside a coil, the material to be heated is transferred from one end to the other end while induction heating is performed, in which the material to be heated is supported within the cylindrical member. At least two rail-like protrusions are provided in the longitudinal direction in a trapezoidal shape whose tip width is smaller than the width of the inner surface of the cylindrical member, and at least two are provided at a substantially constant height from the inner surface of the cylindrical member, and the inner diameter of the cylindrical member is An induction heating device characterized in that the size gradually increases from one end to the other end.