JPH0122329B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a vacuum annealing furnace as an electric furnace for vacuum annealing metal coils using a heater as a heating source, particularly a horizontal vacuum annealing furnace in which metal coils are mounted in multiple stages above and below. Regarding furnaces.

Conventional technology and problems When vacuum annealing metal coils such as aluminum coils in an electric furnace in which a heater is disposed on the entire inner wall of the furnace body, it is possible to uniformly receive radiation heat from the heater for each coil. It is required from the viewpoint of quality to make the temperature distribution uniform, and it is required from the viewpoint of production efficiency to process as many metal coils as possible at once.

Conventionally, bell-shaped furnaces and horizontal furnaces have been generally used as vacuum annealing furnaces for metal coils, but it is difficult to say that either of these can satisfy the above requirements. In other words, in a bell-shaped furnace, multiple metal coils are installed in multiple stages above and below, radially with the axial direction facing the center line of the furnace, and the positions of the coils are alternately shifted horizontally in adjacent stages above and below. By arranging the coils in a fixed position, the heat from the heater is radiated uniformly to each coil.
It is possible to make the temperature distribution of each coil uniform. However, in such a bell-shaped furnace, there is a limit to the amount of coils that can be installed, and a large amount of coils cannot be annealed at one time.

On the other hand, in a horizontal furnace, a large number of coils can be annealed at one time by mounting the coils in multiple stages, one above the other, with the axial direction of each coil aligned with the width direction of the furnace. However, in this case, each coil located in the middle stage has a small radiant heat receiving area as a part of the heat radiation from the heater is blocked by the upper and lower coils, resulting in a difference in temperature distribution across the coils. There were problems in terms of quality.

This invention was made in view of the above circumstances, and aims to provide a vacuum annealing furnace that can uniformize the temperature distribution throughout the coil and can process a large number of coils at once. be.

Means for Solving the Problems For this purpose, the present invention employs basically a horizontal furnace as the vacuum annealing furnace, while retaining the advantage of being able to process a large number of metal coils at once. This furnace is characterized in that an auxiliary heater is provided inside the horizontal furnace in order to increase the amount of heat received by the coil located in the intermediate stage.

In other words, the present invention provides a horizontal vacuum annealing furnace in which a heater is disposed on the entire inner wall of the furnace body, and metal coils are mounted inside the furnace in multiple stages above and below. The gist of the present invention is a horizontal vacuum annealing furnace for metal coils, characterized in that an auxiliary heater is provided at an inwardly proximate position facing a row of coils.

Embodiment Next, the structure of the present invention will be explained based on the embodiment shown in FIGS. 1 and 2.

In these figures, 1 indicates a vacuum annealing furnace according to the present invention, and this vacuum annealing furnace 1 has a cylindrical furnace body 2. This furnace body 2 has a double structure with a heat insulating material 3 of a predetermined thickness disposed on the outside and an inner wall material 4 disposed on the inside. A heater 5 for heating is disposed between the heat insulating material 3 and the inner wall material 4 so as to cover the entire inner wall material. Note that 6 in the figure is a vent hole.

The configuration of the furnace body 2, heater 5, etc. is as follows:
It is no different from a conventional horizontal furnace. Therefore, the metal coil 10 such as an aluminum coil also
As in the past, the coils are mounted in multiple stages above and below in the furnace main body with the direction of the axis 11 of the coils aligned with the width direction of the furnace main body 2, and are mounted with a predetermined distance maintained between adjacent coils. It is assumed that Further, the means for mounting the coil is the same as the conventional one. This embodiment exemplifies the case where the devices are mounted in three stages indicated by symbols A, B, and C from the bottom.

According to the present invention, an auxiliary heater is provided at an inwardly proximate position facing the coil array mounted at the intermediate stage. That is, in the case of the illustrated embodiment, a plurality of auxiliary heaters 7 are provided inwardly protruding from the inner wall material 4 of the furnace body 2 so as to face both end surfaces of each coil 10 belonging to the coil row in the middle stage, ie, the row row. It is being These auxiliary heaters 7 are for increasing the amount of heat received by the coils belonging to stage 2 to bring the coils to a temperature comparable to that of the coils belonging to stages A and C during annealing treatment. Therefore, the auxiliary heater 7 may be of any type, shape, etc. as long as it can realize this purpose. Further, the amount of heat generated by the auxiliary heater 7, the distance between the auxiliary heater and the corresponding coil, etc. are appropriately set to values such that the coil receives the same amount of heat as the upper and lower coils. In the case of an aluminum coil, for example, vacuum annealing is generally carried out at a temperature range of about 100 to 650°C and a pressure range of about 500 to 1×10 ⁻⁵ Torr.

In the vacuum annealing furnace 1 of the illustrated embodiment, by heating the heater 5 provided around the inner wall material 4, the heat from the heater 5 is radiated to each coil 10 installed in the furnace, and the temperature of each coil is rises. Here, for each coil belonging to the coil rows in stage B, thermal radiation from the upper and lower peripheral surfaces of the inner wall material 4 to the vicinity of the coil side peripheral surface is blocked by the coils belonging to the coil rows in stages A and C. As a result, the heat receiving area for the heater 5 is small, and therefore the amount of heat received is small. This decrease in the amount of heat received is compensated for by heat radiation from the auxiliary heater 7, which is placed close to both end faces of the coils, so that each coil in stage 2 is made to work at the same level as the coils in stages 1 and 3. The temperature will be about.

In the illustrated embodiment, the heater 5 is arranged between the inner wall material 4 and the heat insulating material 3, but it may be arranged inside the inner wall material 4. Also, the furnace body 2
The structure, shape, etc. are not limited to the illustrated embodiment. Furthermore, although the case in which the coils 10 are mounted in three upper and lower stages is illustrated, the same applies to a mounting arrangement of four or more stages.

Effects of the Invention As explained above, the vacuum annealing furnace according to the present invention basically adopts a horizontal type, thereby making it possible to anneal a large number of metal coils at once. An auxiliary heater is provided at a position close to the inner side facing the coil row installed in the middle stage, and the amount of heat received by the coil in the middle stage is increased so that the amount of heat received is comparable to that of the coils belonging to the coil rows in the top and bottom stages. It was designed to ensure that Therefore, vacuum annealing can be performed with uniform temperature distribution throughout the coil, and it is possible to provide an excellent metal coil with less variation in characteristics in terms of quality, as well as to improve production efficiency.

By the way, it is an aluminum coil made of aluminum foil with a thickness of 0.09mm and a width of 1000mm (weight 600Kg)
were loaded into the furnace in the upper and lower three stages shown in Figures 1 and 2, and heated for 12 hours at a vacuum level of 1 x 10 ^-3 Torr and a set temperature of heater 5 and auxiliary heater 6 at 600°C. After heating, the temperature of the coils at each stage shown as A, B, and C in FIG. 1 was measured, and the temperature of the coils A and C was 560°C, and the temperature of the coil B was 550°C. On the other hand, when we conducted a similar experiment without installing the auxiliary heater 7, we found that the coils A and C were the same.
The temperature was 560°C, but the temperature in coil B was 510°C.
Therefore, it was confirmed that the vacuum annealing furnace according to the present invention can make the temperature distribution of each coil uniform.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing the configuration of an embodiment of the present invention, and FIG. 1 is a vertical cross-sectional view of a vacuum annealing furnace in which metal coils are mounted in three stages, upper and lower, and FIG. FIG. 1... Vacuum annealing furnace, 2... Furnace body, 5... Heater, 7
...Auxiliary heater, 10...Metal coil.

Claims (1)

[Claims] 1 In a horizontal vacuum annealing furnace in which a heater is disposed on the entire inner wall of the furnace body and metal coils are installed in multiple stages above and below, the coil row installed in the middle stage where the radiation heat receiving area is small is A horizontal vacuum annealing furnace for metal coils, characterized in that an auxiliary heater is provided at a facing inner position.