Chemistry: electrical and wave energy – Apparatus – Electrolytic
Reexamination Certificate
1999-12-21
2001-10-23
Gorgos, Kathryn (Department: 1741)
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C204S206000, C204S212000
Reexamination Certificate
active
06306268
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for carrying out continuous electrolytic precipitative deposition processes comprising a rotating cathodic live cylinder with an electrically conductive surface over its entire usable width and one or more anodes disposed, for example, concentrically and spaced apart with respect to the live cylinder and through the spacing volume between the live cylinder and the anode flows an electrolyte comprising in dissolved form the metal to be precipitated, with which live cylinder at margin regions thereof are disposed means for preventing a coating of the margin regions not used by the live cylinder during the electrolytic deposition processes.
A device for producing electrolytically metal strips is known for example from U.S. Pat. No. 2,044,415. A driven cathodic live cylinder forms a spacing volume with anodes disposed concentrically with the cylindrical surface of the live cylinder, which anodes are disposed encompassing the live cylinder for example over an angle of 160 degrees. Through the spacing volume flows the electrolyte comprising the metal to be precipitated. During a current flow the metal, initially comprised in the electrolyte in dissolved form, is deposited on the cathodic surface of the live cylinder. Due to the rotating movement of the live cylinder, the electrolytic coating can subsequently be pulled off as a foil or thin metal strip after it emerges from the electrolyte and can be continuously supplied to succeeding working steps. In the case of this known live cylinder the entire width of the live cylinder is utilized for the electrolytic precipitative deposition processes for forming the metal foil. In order for the live cylinder not to be subjected to an electrolytic coating in its margin region in the transition to its front faces, which would lead to damage of the same, a rubber band which in cross section is circular is used which is supported on the front-face edge of the live cylinder and on a nonconductive flange disposed on the front face of the live cylinder. This sealing rubber band ensures that a current flow toward the front sides of the live cylinder, and thus an electrolytic coating of these regions, is effectively prevented.
Due to the prevention in the margin, as a consequence of the gap, of electrolytic deposition, this prior known device is only suitable for the production of metal strips or foils of a single width, namely the width of the live cylinder. However, this device is unsuitable in order to produce metal strips of varying widths. This known device is also not intended for the single-side electrolytic coating of metal strips.
A device for single-side electrolytic coating of metal strips is known from WO 94/10360. In contact with and disposed about the driven cathodic live cylinder is guided a metal strip to be coated on the outside. The metal strip is supplied via a deflection roller with minimum spacing to the live cylinder and, after the coating, conveyed further on the opposing side via a further deflection roller. The metal strip passes through a spacing volume through which flows an electrolyte, in which the metal strip is coated electrolytically. The spacing volume formed by the strip surface and the anode disposed opposingly is limited laterally by sealings which can be set in the axial direction of the live cylinder for matching them to different widths of metal strips to be coated. These sealings are each supported with a sealing segment in the margin region of the metal strip to be coated. These supported sealing segments contact the surface of the metal strip to be coated at an angle of wrap which is of such a magnitude that a sufficient tightness exists when the metal strip enters the electrolyte.
With such a device, metal strips of varying widths can be coated on a single side. Since, due to the sealing measures, these portions are not wetted with electrolyte, the portions of the live cylinder not used in the case of narrow metal strip widths are protected against electrolytic coating. Even if with this known device undesirable electrolytic coating of the unused margin regions of the live cylinder is prevented, in particular in the case of coating very thin metal strips, for example foils, the support of the sealing segments on the metal strips represents a disadvantage. Especially in the case of very thin metal strips to be coated these sealing segments, past which the metal strip to be coated is pulled, leave marks. The margin portions of such strips or foils must subsequently be detached in a succeeding working step.
With an object according to WO 94/10360 the electrolytic metal strip production cannot be carried out.
Building on this discussed prior art the invention is therefore based on the task of proposing a device according to the species in which not only the usable region of the live cylinder is settable and the unused regions of the live cylinder are effectively protected against undesirable electrolytic coating, but with which electrolytic metal strip production as well as single-side electrolytic coating of metal strips is possible.
SUMMARY OF THE INVENTION
This task is solved according to the invention thereby that associated with the live cylinder on each side is a shielding strip projecting beyond the cylindrical surface of the live cylinder and comprising an electrically insulating material, which is disposed between the cathodic live cylinder and the anode(s) and bordering on a usable region utilized by the live cylinder for electrolytic deposition processes, and electrically shielding a margin region of the live cylinder not used during the deposition process and encompassing the live cylinder at least at the level of filling of the electrolyte, with an inner side of the shielding strip facing toward the usable region comprising a shoulder extending over the length of the shielding strip.
By providing a shielding strip, usefully of a flexible strip comprising an electrically nonconductive material, which is disposed such that it encompasses the live cylinder in the region of the electrolyte, an electrically effective shielding is generated between the anode(s), which usefully is/are nondetachable, and the margin regions of the live cylinder, serving as the cathode, covered by the shielding strip. An electric current flow between the anode and the cathode therefore only takes place in the usable region of the live cylinder not covered by the shielding strips such that the electrolytic coating is restricted to the particular usable region of the live cylinder. In contrast, in the margin regions of the live cylinder covered by the shielding strips, current flow, and thus also electrolytic coating, does not take place. In order to ensure that also in the margin portion of the shielding strip, facing the usable region of the live cylinder, an increased electrolytic coating of the live cylinder surface is prevented by the shoulder formed on the shielding strip and directed toward the live cylinder. It is thereby achieved that in the outer, a layer thickness exists which toward the strip edge is decreased to zero such that also no coating of the live cylinder takes place outside the usable region.
The usable region of the live cylinder can be determined, for example, thereby that for different deposition processes shielding strips of different widths are provided such that they shield the live cylinder at the margin regions thereof.
The device according to the invention is suitable for the electrolytic production of metal strips or foils as well as for the single-side electrolytic coating of metal strips since the device utilizes for the protection of the unused live cylinder margin regions the principle of electric shielding and not the principle of fluid sealing, such as is used, for example, in the case of the subject matter of WO 94/10360. For the single-side electrolytic coating of metal strips the margin region of the metal strip to be coated engages the shoulders of the shielding strips, facing toward the usable region of the live cylinder,
Collard Michel
May Hans Josef
Schnettler Roland
Circuit Foil, S.A. of Luxemburg
Flanagan John K.
Flanagan John R.
Flanagan & Flanagan
Gorgos Kathryn
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