Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/08—Electroplating with moving electrolyte e.g. jet electroplating
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
  • C25D17/16—Apparatus for electrolytic coating of small objects in bulk
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D21/00—Processes for servicing or operating cells for electrolytic coating
  • C25D21/12—Process control or regulation
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D7/00—Electroplating characterised by the article coated
  • C25D7/06—Wires; Strips; Foils
  • C25D7/0607—Wires

Definitions

• the present invention relates to an installation for continuously
• EP-A1 -0 297 178 of applicant discloses an installation for electroplating a plurality of steel wires.
• the steel wires function as cathode and a soluble anode provides the metal to be coated on the steel wires.
• US-A-5,478,457 discloses an apparatus for the continuous electrolytic plating of wire-shaped objects.
• the wires follow a zigzag path of travel past a succession of anodes and cathodes. There is sliding contact between the cathodes and the wires.
• the anodes may have channel-shaped recesses through which the wires are running. Holes are made in the bottom of the anodes to allow flow of the
• GB-A-2 067 223 and US-A1 -2002/001 1419 disclose an electro-deposition apparatus for electroplating a film on a single planar substrate.
• homogeneous coating means that there is no thickness variation in the coating over the circumference of the elongated elements.
• the voltage level on the elongated elements may influence the eventual coating weight on the elongated elements.
• the installation comprises a plurality of elongated metal elements to be plated.
• the elongated metal elements function as cathodes.
• the installation further comprises a bath of an electrolyte wherein the elongated metal elements are immersed and are travelling, one adjacent and parallel to another one, along a rectilinear path.
• the bath comprises a collector space positioned under the elongated metal elements for receiving the electrolyte.
• the bath further comprises an anode and a distribution plate between the collector space and the elongated metal elements.
• the distribution plate has a multiplicity of openings for allowing flow of an electrolyte.
• the installation has a pump for circulating the electrolyte in the bath in a direction from the collector space through the distribution plate to the elongated metal elements.
• the collector space causes first flow losses to the flow of the electrolyte.
• the distribution plate has a multiplicity of openings for allowing the flow of the electrolyte. These openings in the distribution plate cause second flow losses to the flow of the electrolyte. Each of the second flow losses through the distributor plate are at least five times, preferably more than ten times, most preferably more than hundred times, greater than the first flow losses in the collector space.
• the collector space has a first cross-section for allowing the flow of the electrolyte and the distribution plate has a multiplicity of openings allowing the flow of the electrolyte from the collector space towards the elongated elements.
• the openings in the distribution plate have a second cross-section which is at least three times, and preferably at least ten times, and most preferably much more times, smaller than the first cross-section.
• the elongated metal elements may be steel wires, steel cords, steel
• the other metal to be coated on the elongated metal elements may be zinc, tin, nickel, copper, or alloys thereof.
• Noble metals such as gold, silver, platinum are not excluded either.
• the elongated metal elements function as cathode, the electrical charge is transmitted to the elongated metal elements through driving or guiding rolls or wheels which are negatively charged.
• the number of elongated metal elements running in parallel to each other and to be coated simultaneously can vary from twenty to forty and more.
• the distribution plate is different from the anode.
• the distribution plate is preferably a flat plate and does not provide
• Figure 1 is a cross-section of an installation according to the prior art.
• Figure 2 is a cross-section of an electroplating installation according to the invention.
• Figure 3 is an electrical scheme used to explain in another way the functioning of the distribution plate.
• Figure 1 illustrates the working of an installation 10 for electroplating steel wires 12 according to the prior art.
• Steel wires 12 run parallel and rectilinear with respect to each other in an electrolyte bath 14.
• An anode 16 soluble or not, is installed under the wires 12.
• the steel wires function as cathode. Ions leave the anode 16 and travel through the electrolyte towards the negatively loaded steel wires 12.
• a collector space 17 is arranged below the anode 16.
• a circulation pump 18 circulates electrolyte from the collector space 17 over or through the anode 16 towards the steel wires 12 and the surface of the electrolyte bath 14. An amount of electrolyte is overflowing the bath 14 at upstream and downstream side and is recuperated (not shown).
• the flow of the electrolyte in the neighbourhood of the steel wires 12' which are close to the pump 18 may be completely different than the flow of the electrolyte in the neighbourhood of the steel wires 12" which are most remote from the pump 18.
• the inventors have noticed that these differences may negatively influence the homogeneity and equality of coating on the steel wires 12. After having discovered this, the challenge was to make as uniform as possible the flow of electrolyte around each and every steel wire 12, 12', 12".
• Figure 2 illustrates an electroplating installation 20 according to the
• Steel wires 21 run parallel to each other in an electrolyte bath 22.
• anode 23, soluble or not, is installed under the wires 21 .
• the steel wires 21 function as cathode. Ions leave the anode 23 and travel through the electrolyte towards the negatively loaded steel wires 21 .
• a collector space 24 is arranged below the anode 23.
• a circulation pump 25 circulates electrolyte from the collector space 24 over or through the anode 23 towards the steel wires 21 and the surface of the electrolyte bath 22. An amount of electrolyte is overflowing the bath 22 at upstream and downstream side and is recuperated (not shown).
• the main difference with the prior art installation 10 is the presence of a distribution plate 26, different from the anode 23, located between the collector space 24 and the anode 23.
• This distribution plate 26 has a plurality of small openings which present a high resistance to the electrolyte flowing through. The flow losses of the electrolyte through the openings of the distribution plate are so high in comparison with the flow losses of the electrolyte in the collector space 24 that the losses of the electrolyte in the collector space 24 can be neglected.
• Figure 3 depicts an electrical scheme 30 with a lot of electrical resistors 32 in series.
• the resistors 32 represent the flow losses of the electrolyte in the collector space 24.
• the resistors 32 have all a low resistance R c .
• the resistors 34 represent the flow losses of the electrolyte in each opening of the distributor plate 26 and have a high resistance Rh, which is much higher than R c , for example more than hundred times higher, more than thousand times higher.
• the total losses of the electrolyte flow from the pump to the elongated elements may be higher due to the presence of the distributor plate. As a result, a higher pump height may be necessary.
• the distribution plate 26 may be made of any material chemically resistant against the used chemicals in the electrolyte.
• the distribution plate may have a thickness varying from 1 mm to 30 mm, e.g. from 2 mm to 20 mm.
• any type of opening (square, rectangular, circular, hexagonal?) can be used. If circular the openings in the distribution plate may have a diameter varying between 3 mm to 20 mm diameter.
• the invention can be practiced for soluble and non-soluble anodes and for various types of metal and for electrolytes.
• the anode is made of an electrically conductive material such as stainless steel.
• a distribution plate is applied to a copper plating installation of forty steel wires.
• the electrolyte can be copper-citrate, copper-amine, copper- tartrate, copper-sulfate, copper-pyrophosphate, copper fluoroborate or copper cyanide.
• the anode is formed by a soluble copper anode lying on a supporting plate.
• the cathode current density varies between 1 and 20 A/dm 2 .
• the speed of the steel wires may vary between 10 m/min and 150 m/min.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Automation & Control Theory (AREA)
• Electroplating Methods And Accessories (AREA)

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Publications (1)

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• 2012
  • 2012-05-03 US US14/131,065 patent/US20140158528A1/en not_active Abandoned
  • 2012-05-03 CN CN201280031797.0A patent/CN103649379A/zh active Pending
  • 2012-05-03 EP EP12719367.0A patent/EP2729603A1/de not_active Withdrawn
  • 2012-05-03 WO PCT/EP2012/058073 patent/WO2013004414A1/en active Application Filing

Non-Patent Citations (1)

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