JP3662643B2 - Bottomed metal can drying method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for drying a bottomed metal can such as a battery can using a high frequency induction heating apparatus.
[0002]
[Prior art]
Conventionally, in a method for producing a bottomed metal can used for a battery can or the like, a method in which a metal plate is processed into a predetermined bottomed metal can shape such as a battery can and then CFC cleaning is generally employed. In addition, water cleaning instead of chlorofluorocarbon cleaning has been attempted. However, when water cleaning is performed, rust is generated by moisture adhering to the bottomed metal can, so that the rust is generated and dried to prevent corrosion. is required.
[0003]
Conventionally, hot air drying has been mainly considered as this drying method. In addition, although it is not a drying method for bottomed metal cans, a drying method using high frequency induction heating is a method for baking and drying paints. The invention is disclosed in JP-A-1-194972.
[0004]
[Problems to be solved by the invention]
However, the destruction of the ozone layer by fluorocarbons has become a global problem, and in order to avoid the adverse effects of ultraviolet rays on the human body, it is required to eliminate the use of fluorocarbons and the conventional fluorocarbon cleaning can be used. As a result, there has been a need for an alternative cleaning method to replace CFC cleaning in the manufacturing process of bottomed metal cans.
[0005]
However, when water washing is used as described above, subsequent drying is necessary. Conventionally, hot air drying by indirect heating with a sheathed heater or gas, heavy oil or the like has been mainly considered as the means. . However, in order to dry small parts of bottomed metal cans that have been deep-drawn like battery cans with hot air, it is difficult to dry the inside of bottomed metal cans. In view of energy efficiency, this method is not preferable because it is not an excellent method, and drying takes time and productivity is poor, and the apparatus becomes large.
[0006]
Infrared heating can also be considered as a rapid drying method to increase productivity, but bottomed metal cans such as battery cans after processing into a predetermined shape are in a mirror state, often reflecting infrared rays, and efficiency It is difficult to dry well, and this method is not suitable as a method for drying a bottomed metal can.
[0007]
Further, a drying method using high-frequency induction heating is disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1-194472, and is used when baking and drying a paint applied to an automobile body. However, although this drying method solves the drawbacks such as low thermal efficiency of hot air drying, the drying process is essentially the same as hot air drying in that it promotes solvent volatilization. Therefore, if this drying method is simply used as a method for drying a bottomed metal can that has been deep-drawn such as a battery can, it will be dried by evaporating all of the water adhering to the battery can by induction heating, Since there is no great difference in the drying process, it is not an appropriate method for drying a bottomed metal can that requires rapid drying. Further, since the shape of the heating coil disclosed in Japanese Patent Laid-Open No. 1-194472 is intended for a large body called an automobile body, it is planar in accordance with the body of the automobile, but this occurs there. The eddy current is also almost flat according to the body of the car, so the efficiency of induction heating cannot be improved, it takes a relatively long time to dry one workpiece, and many small parts made of bottomed metal cans are used. It is not a suitable heating coil shape in the case of drying in a flow operation within an extremely short time.
[0008]
As described above, conventionally, there has been a problem that there is no optimal drying method for bottomed metal cans, and thus it has been difficult to use water cleaning as an alternative to CFC cleaning.
[0009]
In order to solve the above problems, the present invention is a method for drying a bottomed metal can that has been washed with water or warm water, and in which the bottomed metal can is fixed with a magnet with its opening directed downward, and is induction-heated at high frequency. By transporting the inside of the device and generating an alternating magnetic field so that eddy currents flow on the metal surface in the high frequency induction heating device, the water attached to the surface of the bottomed metal can is heated rapidly, and the bottomed metal The bottomed metal can is dried by peeling off from the can surface and allowing it to fall naturally in the form of water droplets.
[0010]
This high-frequency induction heating device is preferably configured to induce current in the circumferential direction of the bottomed metal can.
[0011]
Further, the high-frequency induction heating device includes a conveying means for continuously conveying the bottomed metal can, a pair of parallel coil portions and both parallel coil portions extending along the conveyance direction on both sides of the conveyance path of the bottomed metal can. It is preferable to have a heating coil portion including a pair of connection coil portions that connect the two.
[0012]
Furthermore, it is preferable that the parallel coil portion of the high frequency induction heating device is formed by laminating a plurality of coil elements.
[0013]
If the above-mentioned bottomed metal can is a battery can, it is optimal for drying the battery can.
[0014]
According to the present invention, since the opening of the bottomed metal can faces downward, most of the water is discharged from the opening after the bottomed metal can is washed with water or hot water. Then, the bottomed metal can is carried into the high-frequency induction heating device, and at this time, an alternating current is caused to flow through the heating coil in the high-frequency induction heating device, thereby generating an alternating magnetic field. When the metal can passes or is held in the magnetic field, a voltage is induced in the bottomed metal can which is a conductor by electromagnetic induction, and an induced current flows in the bottomed metal can. This current generates Joule heat in the bottomed metal can, and the bottomed metal can itself immediately and efficiently generates heat. This induced current is called an eddy current, and since this eddy current has a property of flowing in a concentrated manner on the surface of a metal or the like that is a conductor, that is, a skin effect, in the case of the present invention, it is bottomed by a high frequency induction heating device. The surface of the metal can generates heat intensively.
[0015]
As a result, the water adhering to the surface of the bottomed metal can is rapidly heated, causing partial boiling, and the water adhering to the surface of the bottomed metal can is peeled off from the surface of the bottomed metal can at the sudden boiling portion. A phenomenon occurs in which spherical water droplets are formed by the surface tension and are repelled on the surface of the bottomed metal can. Then, the water droplets on the surface of the bottomed metal can naturally fall from the surface of the bottomed metal can by its own weight, and the water droplets from the opening portion because the opening portion of the bottomed metal can faces downward. Can be discharged. Thus, without waiting for all of the water adhering to the surface of the bottomed metal can to evaporate, much of the water becomes water droplets and is discharged from the opening of the bottomed metal can. Thus, the bottomed metal can can be efficiently dried as compared with the case where the drying is completed only after the heat of evaporation is given to the moisture. In addition, since the bottomed metal can itself generates heat, it is not necessary to heat the air that is the medium, and the power consumption required for drying the bottomed metal can can be greatly reduced.
[0016]
In addition, by setting the direction in which the eddy current flows to the circumferential direction of the bottomed metal can, a closed circuit can be formed on the surface of the bottomed metal can, and the heating efficiency by the eddy current can be improved.
[0017]
In addition, by providing a means for transporting the bottomed metal can, by providing a heating coil portion parallel to the transport direction on both sides of the transport path, a plurality of the bottomed metal cans can be efficiently dried at the same time, Productivity can be improved.
[0018]
And by laminating | stacking the coil element of this parallel coil part extended in the conveyance direction of a bottomed metal can, uniform heat_generation | fever can be produced over the full length of a bottomed metal can, and more rapid drying is attained. .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to drying of a cylindrical battery can which is a bottomed metal can will be described with reference to FIGS.
[0020]
Here, FIG. 1 shows an outline of the high-frequency induction heating device of the present embodiment and how the battery can is conveyed. FIG. 2 is a longitudinal sectional view of the high frequency induction heating device and the battery can. FIG. 3 shows the arrangement of the heating coils in the high frequency induction heating apparatus. FIG. 4 is a process schematic diagram from washing to drying of the battery can.
[0021]
As shown in FIG. 4, the battery can 1 has a nickel-plated steel plate formed in a predetermined shape, and is moved from the battery can supply part 41 to the washing part 42 by the magnet conveyor 40a. Cutting oil and other dirt adhering to the battery can 1 are removed with hot water, and the battery can 1 is transferred to a preliminary drying step 43 and a drying step 44.
[0022]
The battery can 1 is dried in a preliminary drying step 43 and a drying step 44 using the high-frequency induction heating device 10. The provision of the preliminary drying step 43 before shifting to the drying step 44 prevents the ambient temperature in the vicinity of the battery can 1 from changing suddenly, and the battery can 1 is efficiently dried by the high frequency induction heating device 10. This is to make it happen. In the preliminary drying process 43, warmed dry air is blown to the battery can 1, and an iron pipe 43b is used for the air blowing path, and a heating coil 43a is wound around the iron pipe 43b. A method of producing warm air by indirectly heating the dry air by heating the iron pipe 43b by high frequency induction heating is employed. As a result, the thermal efficiency is improved, uniform hot air can be obtained, and the production facility can be made compact.
[0023]
The drying process 44 includes a magnet conveyor 40 b and the high frequency induction heating device 10. The magnet conveyer 40b conveys the battery can 1 while being fixed by a magnet, and has a wire mesh structure so that moisture discharged from the opening 2 of the battery can 1 can be discharged. The battery can 1 is placed on the magnet conveyor 40b so that the opening 2 faces downward.
[0024]
As shown in FIGS. 1 to 3, the high-frequency induction heating apparatus 10 includes a heating coil 11, a coil support 12, an outer case 13, and a fixing portion 14. As shown in FIG. 3A, the heating coil 11 is formed by stacking a plurality of coil elements 11d made of conductive wires in a hollow concentric elliptical shape, and the ellipse long axis is used as a symmetry axis, as shown in FIG. 3B. It has a bent shape. Then, a pair of parallel coil portions 11a and a pair of connecting coil portions 11b that connect them at both ends are configured, and in order to cause an alternating current to flow through the heating coil 11, the terminal portion 11c is connected to a high-frequency current generator. Connect to. Then, the heating coil 11 is formed on the surface of a glass fiber coil support 12 having a substantially U-shaped cross section and having a transport space 18 for transporting the battery can 1 as shown in FIG. It winds and the outer case 13 made of glass fiber is fitted from above. And the high frequency induction heating apparatus 10 can be arrange | positioned in the drying process 44 of the battery can 1 by fixing the fixing | fixed part 14 formed in the downward extension part of the coil support body 12 to the apparatus frame 19 with a volt | bolt etc. The reason why the glass fiber is used for the coil support 12 and the outer case 13 is that it is hardly affected by the alternating magnetic field by the heating coil 11 and the heat generation can be prevented.
[0025]
Next, a method for drying the battery can 1 using the high frequency induction heating apparatus 10 will be described in detail with reference to FIGS.
[0026]
When a high-frequency alternating current is passed through the high-frequency induction heating device 10, an alternating magnetic field is generated in the pair of parallel coil portions 11 a and connection coil portions 11 b in a direction perpendicular to the conveying direction of the battery can 1. When the battery can 1 is carried into the high-frequency induction heating device 10, the battery can 1 as a conductor enters the alternating magnetic field, and a voltage is induced in the battery can 1 by electromagnetic induction. An induced current flows in the direction perpendicular to the direction, that is, in the direction indicated by the arrow in FIG. The induced current is an eddy current, and the parallel coil portion 11a extends in the conveyance path 40 of the battery can 1 as in the present embodiment. Therefore, the eddy current is in the circumferential direction of the battery can 1 as shown in FIG. Therefore, a closed circuit is formed. Therefore, when an optimum frequency is selected and a high-frequency current is passed through the high-frequency induction heating device 10, a strong eddy current flows in the closed circuit, and a large amount of Joule heat is generated in the battery can 1, and due to the skin effect. The vicinity of the surface of the battery can 1 generates heat rapidly. Moisture adhering to the surface of the battery can 1 can be rapidly heated by such high-frequency induction heating, and the water boils suddenly, and the surface tension naturally causes the water to become spherical water droplets and be repelled from the surface of the battery can 1. It falls and is discharged from the opening 2. For this reason, the moisture adhering to the battery can 1 can be rapidly dried. Since the battery can 1 itself generates heat by this high-frequency induction heating, the thermal efficiency is remarkably superior to heating the battery can indirectly by hot air or the like, and drying can be completed in a short time. It is.
[0027]
In this embodiment, since the parallel coil part 11a in the heating coil 11 of the high frequency induction heating device 10 extends in the conveying direction of the battery can 1, it is possible to heat a plurality of battery cans 1 simultaneously and uniformly. Further, the battery can 1 can be continuously dried while being conveyed by the magnet conveyor 40b without being stopped. Thereby, productivity can be improved. In FIG. 4, only one high-frequency induction heating device 10 is provided. However, several high-frequency induction heating devices 10 can be continuously provided in series according to the shape described above. Since the conveyance speed of the battery can 1 can be increased while being reliably dried, productivity can be further improved.
[0028]
The parallel coil portion 11a of the high frequency induction heating device 10 may be formed by stacking the coil elements 11c over the entire length of the battery can 1. However, even if it is a part of the battery can 1 as shown in FIG. As long as the battery can 1 is in a range where an alternating magnetic field is generated, the battery can 1 can be sufficiently dried. For this reason, the conducting wire in the heating coil 11 can be saved and the cost of equipment can be reduced.
[0029]
Further, as shown in FIGS. 1 and 2, the present invention is not limited to the case where the battery can 1 is dried so that the opening 2 of the battery can 1 faces downward, and the battery can be made so that the opening 2 faces obliquely downward. The case where the can 1 is dried is also included in the scope of the present invention.
[0030]
Further, the method for drying a round battery can has been described above, but it can also be used for another method for drying a bottomed metal can, such as a case made of a square battery can or a case made of a bottomed metal can. Needless to say.
[0031]
【The invention's effect】
According to the present invention, the bottomed metal can itself is instantly heated by the high-frequency induction heating device, so that most of the water adhering to the surface of the bottomed metal can can be easily formed into water droplets and discharged from the opening. Thus, the bottomed metal can can be dried within a short time in combination with the evaporation of the moisture.
[0032]
According to this drying method, compared with the conventional indirect heating method, the thermal efficiency is remarkably improved and energy saving can be achieved.
[0033]
In particular, it is effective as a method for drying small bottomed metal cans such as battery cans.
[Brief description of the drawings]
FIG. 1 is a perspective view of a high frequency induction heating apparatus according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of the high-frequency induction heating device and a battery can inside it.
FIGS. 3A and 3B show a heating coil according to the present invention, FIG. 3A is a plan view showing a laminated state of the heating coils, FIG. 3B is a perspective view showing a bent shape thereof, and FIG. It is a perspective view which shows the state wound.
FIG. 4 shows steps from washing to drying of the battery can in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery can 2 Opening part 10 High frequency induction heating apparatus 11 Heating coil 11a Parallel coil part 11b Connection coil part 11d Coil element

Claims (5)

In a method of drying a bottomed metal can that has been washed with water or warm water, the bottomed metal can is transported through a high- frequency induction heating device while being fixed by a magnet with its opening facing downward, and the high-frequency induction heating device By generating an alternating magnetic field so that eddy currents flow in a concentrated manner on the metal surface, the water adhering to the surface of the bottomed metal can is heated suddenly and peeled off from the surface of the bottomed metal can to form a natural water droplet. A method for drying a bottomed metal can, comprising dropping the bottomed metal can to dry.   The bottomed metal can drying method according to claim 1, wherein the high frequency induction heating device induces an electric current in a circumferential direction of the bottomed metal can. The high-frequency induction heating device connects a conveying means for continuously conveying a bottomed metal can, a pair of parallel coil portions extending along the conveyance direction, and both parallel coil portions on both sides of a bottomed metal can conveyance path. The bottomed metal can drying method of Claim 1 or 2 which has a heating coil part provided with a pair of connection coil part. The method for drying a bottomed metal can according to claim 3 , wherein the parallel coil portion of the high frequency induction heating device is formed by laminating a plurality of coil elements. The method for drying a bottomed metal can according to any one of claims 1 to 4 , wherein the bottomed metal can is a battery can.

Images