Apparatus for continuous electrolytic treatment of aluminum article

Abstract: In an apparatus for continuous electrolytic treatment of aluminum web 20 or an alloy thereof, which comprises an electrolytic part, a pre-stage power supply 12 part provided forward the electrolytic part 11, a post-stage power supply 13 provided backward the electrolytic part and an power source, at least one electrode in the pre-stage power 17 supply part and at least one electrode 18 in the post-stage power supply part being connected with one pole of the power source, and at least one electrode 16 of the electrolytic part being connected with the other pole of the power source. This apparatus can decrease a running cost such as the electric cost and the cooling cost as well as the facilities cost, can conduct a high speed treatment and increase the thickness of a film without fusing an aluminum article, even if the aluminum article has a small sectional area, such as a wire, a foil or a thin web. The electrolytic treatment can stably continue without preparing some means for preventing corrosion, leak and the like at the time that the line is speeded up and the thickness of the film is increased.

Description: BACKGROUND OF THE INVENTION This invention relates to an apparatus for continuous electrolytic treatment of a web made of aluminum or an alloy thereof, particularly to an apparatus for electrolytic treatment capable of solving problems occurred during a high speed driving of an electrolytic line and during electrolysis of a thick film. A continuous electrolytic treatment has been usually utilized in a wide range such as an anodic oxidation an electrolytic colouring, an electrolytic polishing and an electrolytic etching, used in manufacturing of a support for printing plate, an alumite wire, an electrolytic capacitor or the like. A conventional continuous electrolytic treatment for an aluminum product was conducted by the electrolytic treatment disclosed in Japanese Patent KOKAI Nos. 48-26638 and 47-18739 and Japanese Patent KOKOKU No. 58-24517, and the method is usually called as the submerged power supply system. An apparatus for the electrolytic treatment according to the submerged power supply system is shown in Figure 4. This apparatus is in a type of the anodic oxidation using direct current and is composed of three parts, i.e. a power supply bath 2 for charging an aluminum article 1 with a negative charge, an electrolytic bath 3 for the electrolytical treatment of the aluminum article 1 charged with a negative charge and an intermediate part 4 for preventing a short in the liquid between the power supply bath 2 and the electrolytic bath 3. A power supply electrode 5 and an electrolysis electrode 6 are disposed in the electrolyte solution of the power supply bath 2 and the electrolytic bath 3, and the power supply electrode 5 is connected to the electrolysis electrode 6 through a direct current source 7. In said apparatus for electrolytic treatment, the electric current from the direct current source 7 flows to the aluminum product 1 through the electrolyte solution from the power supply electrode 5 in the power supply bath 2, flows in the direction of the electrolytic bath 3 in the aluminum article 1 and flows to the electrolysis electrode 6 through the electrolyte solution from the aluminum product 1 in the electrolytic bath 3. Thus, an oxide film by the anodic oxidation is formed on the surface of the aluminum article 1. According the submerged power supply system, since the article to be treated is not contacted with an electrode or the like, the occurrence of spark during supplying electricity, the occurrence of damages and the like are prevented. Therefore, a line of an electrolytic treatment having a high stability can be provided. However, there were some problems in the above mentioned apparatus for electrolytic treatment. First, the speedup of a line of electrolytic treatment and the increase in a thickness of the oxide film by the anodic oxidation can not be conducted in low cost. That is, in the case that the line of electrolytic treatment is speeded up for improving productivity and in the case that the thickness of the oxide film by the anodic oxidation is increased for improving quality, an amount of supply current is necessary to be increased, and voltage drop caused by ohmic loss is increased in the aluminum article with increasing a supply current. Therefore, to increase a electrolytic voltage of a source is necessary. When the electrolytic voltage is increased, since the electric energy is increased, the running cost is increased, and since a capacity of the source is necessary to be large, the plant investment is increased. Besides, since an electrolytic voltage is great, Joule heat greatly generates in the aluminum article between the power supply electrode 5 and the electrosis electrode 6. As a result, a cooling cost for cooling the aluminum article and the electrolyte solution descending to a prescribed normal temperature increases. As described above, when the line of electrolytic treatment is speeded up in the conventional apparatus, the cost becomes to be great. Second, in the case that the aluminum article has a small sectional area, the speedup of the line for electrolytic treatment is difficult. That is, since the whole current supplied by a power source flows into the aluminum article at the intermediate part between the power supply part and the electrolytic part, when the amount of supplied current is great, the aluminum article having a small sectional area such as a wire, a foil and a thin web heats up greatly and fuses. Therefore, in the case of the aluminum article having a small sectional area, there is a limit in an amount of supplying current. As a result, the speedup of a line for electrolytic treatment and the increase in a thickness of an oxide film by the anodic oxidation are difficult. Third, countermeasures for preventing corrosion, leak and the like are necessary. That is, when a process using an organic solvent such as a coating process is necessary as a post-process of the electrolytic treatment, the aluminum article after the electrolytic treatment process is generally grounded through a meaning such as a grounding roll in order to prevent explosion, flash and the like caused by the elevation of electric potential of the aluminum article in the post-process. However, in this case, though the electric potential of the aluminum article after the electrolytic treatement bath is kept at almost the same electric potential as the electric potential of the earth, the electric potential of the aluminum product prior to the electrolytic treatment bath is kept at a greater electric potential than the electric potential of the electrolytic treatment bath. Electric current flows accordingly forward in the line through the aluminum article, and then comes back to the direct current source through the pre-treatment apparatus and the post-treatment apparatus for the electrolytic treatment apparatus. As a result, a circuit composed the aluminum article, the pre-treatement apparatus, the post-treatment apparatus and the like occurs. Troubles, such as corrosion of metal members used in a pipe and a pump, spark trouble and leak, occur in various treatment apparatuses wherein a pre-treatment of the electrolytic treatment apparatus is conducted by such an electric current. Therefore, a non-corrosive material or an insulating material must be used in order to prevent the occurrence of the troubles, facilities accordingly become complex. As a result, the facilities cost and the maintenance cost increase greatly. Moreover, when the line for electrolytic treatment is speeded up in order to improve productivity, or when the thickness of the oxide film by the anodic oxidation is increased in order to improve a quality, to elevate an amount of the electric current supply is necessary, electric potential accordingly become greater at the aluminum article before the electrolytic treatment bath than the electric potential of the bath, and this point was particularly great problem. In US-A-3,989,605 as well as in US-A-4, 002, 546, there are disclosed treatment apparatuses for an aluminum web wherein said aluminum web passes successively through a current supplying bath and an anodic oxidation bath and an electrolytic coloring bath, whereby the anodes of the current supply and colouring baths are commonly connected to the positive terminal of a power supply whilst the cathode of the anodic oxidation bath is connected to the negative terminal of said power supply. An object of the invention is to provide an apparatus for electrolytic treatment capable of decreasing a running cost such as the electric cost and the cooling cost as well as the facilities cost. Another object of the invention is to provide an apparatus for electrolytic treatment capable of conducting a high speed treatment and increasing the thickness of a film without fusing an aluminum web article, even if the aluminum article has a small sectional area, such as a thin web. Further object of the invention is to provide an apparatus for electrolytic treatment capable of stably conducting the electrolytic treatment without preparing some means for preventing corrosion, leak and the like at the time that the line is speeded up and the thickness of the film is increased. The present invention has been made in order to achieve the above objects, and provides apparatuses for continuous electrolytic treatment of aluminum web or an alloy thereof, as defined in claims 1 and 2. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic block diagram illustrating an apparatus embodying a comparative example. Figure 2 is a schematic block diagram illustrating an apparatus embodying the invention. Figure 3 is a schematic block diagram illustrating another apparatus embodying the invention. Figure 4 is a schematic block diagram illustrating a conventional apparatus. 11 ... Electrolytic bath 12 ... First power supply bath 13 ... Second power supply bath 17, 22, 26 ... Power supply electrodes in bath 12. 18, 23, 27 ... Power supply electrodes in bath 13. 16, 21, 25 ... Electrodes in bath 11. 19, 24, 28 ... Direct current power source. DETAILED DESCRIPTION OF THE INVENTION In the apparatuses of the invention, the first power supply bath and the second power supply bath are connected with the same power source, miniaturization of the apparatus, saving of the facilities cost and maintenance cost, stability in manufacturing and the like are improved. The amount of electric current for supplying to the first power supply bath and the second power supply bath may be set arbitrarily, it is preferred that the whole amount of electric current for supplying to the first power supply bath is the same as the whole amount of electric current for supplying to the second power supply bath, in view of achieving the effect of the invention. Besides, a control apparatus controlling the electric current supplied to two power supply baths may be provided. The apparatus comprises three power sources and an amount of electric current to be supplied by each power source may be equal, or the current density may be gradually elevated. The power sources are connected as shown in Figs. 2 and 3. The wave form of the power source is selected from direct current wave forms, alternating current wave forms, direct-alternating superposition wave forms and the like so as to achieve a desired quality. The electrode may be disposed on one side of the aluminum article only or on both sides, and in the case of the former, the electrode may be disposed at the upper position or lower position. Besides, the location of the pole of the power supply bath may be different from the electrode of the electrolytic bath. The electrolyte solution may be aqueous sulfuric acid solution, aqueous phosphoric acid solution, aqueous oxalic acid solution and mixture solution thereof, and a solution suitable for obtaining a desired quality is selected among them. The temperature and concentration of the electrolyte solution can be arbitrarily selected. The electrolyte solutions of the two power supply baths and the electrolytic bath may be identical or different. Moreover, the above apparatus may be used as one unit, and a plurality of the units may be connected in the longitudinal direction. A grounding means, such as a grounding roll, may be provided. In the apparatuses for continuous electrolytic treatment of the invention, there are two routes for supplying electric current to the electrolytic bath i.e., one is the route through the first power supply bath and the other is the route through the second power supply bath. Therefore, the amount of the electric current becomes half of the amount of the electric current in one route only, and the electric voltage decreases during the electrolytic treatment. Moreover, since the electric current flows to the electrolytic bath through two routes, the length of the aluminum product through which the electric current flows is shortened, and therefore, the electric voltage may be small. Since the electric potential at the aluminum article before the first electrolic supply bath is substantially equal to the electric potential at the aluminum product after the second power supply bath, an electric circuit wherein electric current flows in the pre-treatment apparatus and the post-treatment apparatus does not occur, and the occurrence of corrosion of metal members used in a pipe and pump, spark trouble and leak is prevented. In fig. 1, the numeral 11 indicates an electrolytic bath, and a first power supply bath 12 is disposed forward and a second power supply bath 13 is disposed backward (based on the traveling direction of the aluminum article) of the electrolytic bath 11, and a part between the first power supply bath 12 and the electrolytic bath 11 is a first intermediate stage 14 and a part between the second power supply bath 13 and the electrolytic bath 11 is a second intermediate stage 15. The electrolytic bath 11, the first power supply bath 12 and the second power supply bath 13 are filled with an electrolyte solution and an electrolytic electrode 16, a first power supply electrode 17 and a second power supply electrode 18 are respectively disposed in them. The first power supply electrode 17 and the second power supply electrode 18 are connected with the plus side of a direct current source 19 and the electrolytic electrode 16 are connected with the minus side of the direct current source 19. The numeral 20 indicates an aluminum article in a web form, and the aluminum article 20 travels to the right direction in the electrolyte solution of the electrolytic bath 11, the first power supply bath 12 and the second power supply bath 13. In a continuous electrolytic treatment using the above apparatus of continuous electrolytic treatment, the aluminum article 1 travels with supplying the direct current source 19. The direct current flows clockwise as shown in an arrow in the figure on the pre-stage side, and flows counterclockwise as shown in an arrow b in the figure on the post-stage side. The aluminum article accordingly works as an anode in the electrolytic bath 11 and an oxide film is formed by the anodic oxidation on the surface thereof. The inventive apparatus for continuous electrolytic bath 11, a first power supply bath 12 and a second power supply bath 13 as in the comparative example, and an aluminum product is disposed as well as in the comparative example. Three electrolytic electrodes 21a, 21b, 21c are provided in the electrolytic bath 11. A first power supply electrode 22 is provided in the first power supply bath 12, and a second electrolytic electrode 23 is provided in the second power supply bath 13. Three direct current sources 24a 24b, 24c are provided. The plus side of the direct current source 24a is connected to the first power supply electrode 22 and the second power supply electrode 23, and the minus side thereof is connected to the electrolytic electrode 21a. The plus side of the direct current source 24b is connected to the first power supply electrode 22 and the second power supply electrode 23, and the minus side thereof is connected with the electrolytic electrode 21b. The plus side of the direct current source 24c is connected with the first power supply electrode 22 and the second power supply electrode 23, and the minus side thereof is connected with the electrolytic electrode 21c. An apparatus for continuous electrolytic treatment shown in Fig. 3 has an electrolytic bath 11, a first power supply bath 12 and a second power supply bath 13 like the comparative example, and an aluminum product is disposed as in the comparative example. Three electrolytic electrodes 25a, 25b, 25c are provided in the electrolytic bath 11. Two first power supply electrodes 26a, 26b are provided in the first power supply bath 12, and two second electrolytic electrodes 27a, 27b are provided in the second power supply bath 13. Three direct current sources 28a, 28b, 28c are further provided. The plus side of the direct current source 28a is connected with the first power supply electrode 26b, and the minus side thereof is connected with the electrolytic electrode 25a. The plus side of the direct current source 28b is connected with the first power supply electrode 26a and connected with the second power supply electrode 27b. The minus side of source 28b is connected with the electrolytic electrode 25b. The plus side of the direct current source 28c is connected to the first power supply electrode 27a, and the minus side thereof is connected with the electrolytic electrode 25c.

Claims: A continuous electrolytic treatment apparatus for the electrolytic treatment of a web of aluminum or an alloy thereof wherein said article moves from an upstream end to a downstream end of the apparatus, said apparatus comprising: a first power supply bath (12) including one electrode (22) and an electrolyte solution; a first intermediate stage (14) an electrolytic bath (11) including three electrodes (21a), (21b), (21c) and an electrolyte solution; a second intermediate stage (15); and a second power supply bath (13) including one electrode (23) and an electrolyte solution; said bath and stages being arranged in sequence along the moving direction of said web, said apparatus further comprising three power sources (24a), (24b), (24c) wherein one pole of each of said three power sources is connected to the electrode of the first power supply bath (12) and of the second power supply bath (13), and wherein the other poles of each of the three power sources are individually connected to one of said three electrodes (21a), 21b), (21c) respectively of said electrolytic bath (11). A continuous electrolytic treatment apparatus for the electrolytic treatment of a web of aluminum or an alloy thereof, wherein said article moves from an upstream end to a down stream end of the apparatus, said apparatus comprising: a first power supply bath (12) including two electrodes (26a), (26b) and an electrolyte solution; a first intermediate stage (14); an electrolytic bath (11) including three electrodes (25a), (25b), (25c) and an electrolyte solution; a second intermediate stage (15); and a second power supply bath (13) including two electrodes (27a) (27b) and an electrolyte solution, said bath and stages being arranged in sequence along the moving direction of said web, said apparatus further comprising three power sources (28a), (28b), (28c), wherein one pole of one (28a) of the three power sources is connected to one (26b) electrodes provided in the first power supply bath (12), one pole of another one (28c) of said three power sources is connected to one electrode (27a) of the two electrodes provided in the second power supply bath (13), and one pole of the third (28b) of said three power sources is connected to the second electrode (26a) provided in the first power supply bath (12) and to the second electrode (27b) provided in the second power supply bath (13), and wherein the other pole of each of said three power sources (28a), (28b), (28c) is connected to one of the three electrodes (25a), (25b), (25c) provided in the electrolytic bath (11).

Inventors: KAKEI TSUTOMU, KANEKO NOBUYOSHI, KAKEI, TSUTOMU, KANEKO, NOBUYOSHI, KAKEI, TSUTOMU, C/O FUJI PHOTO FILM CO., LTD., KANEKO, NOBUYOSHI, C/O FUJI PHOTO FILM CO., LTD.
Applicants: FUJI PHOTO FILM CO LTD, FUJI PHOTO FILM CO., LTD.
Application year: 1992
Main classification: C25D17
IPC codes: C25D11, C25D21, C25D7, C25D17