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EP 0 362 924 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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11.05.1994 Bulletin 1994/19 |
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Date of filing: 21.09.1989 |
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International Patent Classification (IPC)5: C25D 7/06 |
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Apparatus for the continuous electrolytic treatment of wire-shaped objects
Vorrichtung zur kontinuierlichen elektrolytischen Behandlung von Gegenständen in Form
von Draht
Appareillage pour le traitement électolytique en continu des objets filiformes
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Designated Contracting States: |
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BE DE ES FR GB IT LU NL |
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Priority: |
06.10.1988 BE 8801152
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Date of publication of application: |
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11.04.1990 Bulletin 1990/15 |
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Proprietor: N.V. BEKAERT S.A. |
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8550 Zwevegem (BE) |
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Inventors: |
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- Catteeuw, Mario
B-8550 Zwevegem (BE)
- Cosaert, Pierre
B-8500 Kortrijk (BE)
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References cited: :
US-A- 2 229 423
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US-A- 2 708 181
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Remarks: |
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The file contains technical information submitted after the application was filed
and not included in this specification |
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention relates to an apparatus for the continuous electrolytic treatment of
wire-shaped objects such as e.g. filaments, yarns, cables or strip-shaped bands or
ribbons. This treatment can be either a coating treatment or a pickling treatment.
[0002] The continuous electrolytic galvanizing of wire-shaped objects in a continuous apparatus
whereby the wires are conducted nearly horizontally past a succession of cathodes
and inert anodes is known from U.S. patent 2.695.269. The current-transmitting sliding-contact
points of the cathodes are located just below the electrolyte bath surface. The anodes
plates are completely immersed in the electrolyte. This apparatus makes a relatively
fast electrodeposition possible. However, this set-up of the cathodic supporting arms
with downwardly extending contact fingers above the bath is rather cumbrous and not
very practical. Indeed, this set-up hinders an easy accessibility of the upper bath
surface. Moreover, in the course of time, salt crystals from the bath precipitate
on the supporting arms and the cathode fingers above the bath, which entails frequent
cleaning and maintenance. Besides, the requirement of an even and constant sliding
contact between the cathode fingers and the wires is hard to fulfil . The cathode
fingers have as it were the tendency to vibrate or dance up and down on the wires
as a result of which there are frequent contact interruptions which result in sparking
and consequently in an irregular deposition quality.
[0003] Similar arrangements with downwardly extending cathode carrying hangers respectively
contactors are also known from U.S. patent 2.229.423 respectively from U.S. patent
2.708.181. The object of the invention is now to overcome these drawbacks by immersing
the supporting and current-carrying arms of the successive cathodes in the electrolyte.
This precludes the formation of salt crystals and the maintenance that it entails.
Besides, this set-up has the added advantage that the immersed cathode can cool down
more easily. Indeed, as the wires have a relatively high running speed through the
installation, high current densities are to be used which can cause the cathodes to
heat up considerably. Cooling in liquid and circulating electrolyte is much more effective
than air cooling such as for contact fingers or contact rollers placed above the bath
or at the bath entry and exit, respectively. The accessability of the bath surface
that is markedly improved in accordance with the invention is particularly advantageous
upon starting the apparatus when a new series of wires is to be pulled through from
entry (pay-off) to exit (take-up unit). It also improves the surveyability of the
installation, which makes process control easier for the operator.
[0004] It is therefore an object of the invention to provide an apparatus for the continuous
electrolytic treatment of wire-shaped objects, the latter being conducted predominantly
horizontally via suitable transport means through an electrolyte bath past a succession
of anodes and cathodes. In the apparatus, the objects follow a zigzag path of travel
in sliding contact with the successive current-transmitting electrodes connected to
one and the same pole of the power source. The electrodes, i.e. their parts assuring
the sliding-contact, and the elements supporting them are immersed in the electrolyte
bath. Actually, the apparatus comprises an electrode arrangement as stated in the
appended claims.
[0005] In addition to the aforementioned advantages, the application of the zigzag path
of travel over the sliding contacts of said electrodes precludes the tendency to sparking
which occurs with state-of-the-art electrode fingers. Indeed, the considerable transport
tension on the wires between pay-off and take-up unit guarantees a constant and even
contact of the wire with the electrodes at the peaks and valleys of the zigzag path
of travel. It follows that operational reliability and the assurance of a constant
process quality are obtained via a strong simplification of the prior art apparatuses.
[0006] If the treatment apparatus is an electroplating line, said electrodes with sliding
contacts will be connected as cathodes. The wires conducted against the sliding contacts
then constitute the cathode in the coating line and the positive ions of the metal
(e.g. zinc) to be applied will precipitate on them from the electrolyte in the path
of travel at the anodes located opposite the wires.
[0007] For a treatment apparatus in the form of a pickling apparatus, said electrodes will
be connected as anodes. The metal coating to be removed from the passing wires then
dissolves in the electrolyte and deposits on the stationary cathodes at the path of
travel of the wire near these cathodes.
[0008] A coating apparatus as embodiment of the invention will hereinafter be illustrated
with reference to the accompanying figures.
Figure 1 is a vertical section through the set-up of successive electrodes in the
electrolyte bath of the coating line.
Figure 2 represents a view from above of the apparatus with a zigzag path of travel
for the series of wires.
Figure 3 is a cross-section through an inert anode plate of the apparatus as electroplating
line.
Figure 4 shows a vertical section through another electrode set-up for a zigzag path
of travel.
[0009] The electrolysis apparatus in accordance with figure 1 basically comprises an elongate
tank or channel 1 as electrolyte bath. This bath 1 is filled with a suitable electrolyte
up to level 3 so that both the anodes 4 and the cathodes 5 are immersed in it. The
cathode pins 5 are fixed on successive supporting arms 6, 7, 8 (e.g. of copper). The
successive anode sections 9, 10 are mounted between said supporting arms. Said sections
comprise the supporting arms 11 (e.g. of copper) for the anode plates 4, 12. These
are e.g. inert lead anodes. The respective supporting arms for cathodes and anodes
are connected to the current-supply bars 13 and 14. The electrode-supporting parts
(6, 7, 8) of these arms are immersed with the electrodes 5 in bath 1 under the bath
surface 3.
[0010] In order to realize a good electrolysis efficiency, the electrolyte can be continuously
circulated by means of pumps (not shown) and through the bores 16 in the anode plates
towards the surface level 3 of the bath 1. The circulation increases the turbulence
in the bath, which increases the electrolysis efficiency.
[0011] The wire-shaped objects 2 to be coated are now continuously conducted past a succession
of anodes 4, 12 and cathode supports 6, 7, 8 below the electrolyte surface 3. In the
process, the wires drag against the pins 5 fixed on the respective current-carrying
supporting arms 6, 7, 8 as a result of which they are connected as cathode, tracing
a horizontal zigzag path of travel as shown in figure 2. So, the successive peaks
and valleys of the zigzag path of travel are located at these pins 5. The electrodes
themselves comprise a highly conductive but preferably also wear-resistant metal alloy,
e.g. tungsten carbide at the sliding contacts at the zigzag peak/valley positions.
[0012] In each space between two consecutive peak/valley positions, the wires come in the
vicinity of the inert anode plates 4, 12 where the desired metal deposition from the
bath 1 takes place. The anode plates 4, 12 can be designed flat but will preferably
comprise channel-shaped recesses 15 (as sketched in figure 3) at the path of travel
of the wires 2 between two consecutive cathode pins 5. This way, a more even metal
deposition is obtained over the whole wire circumference.
[0013] Figure 4 schematically shows another nearly horizontal zigzag path of travel for
the wires 2. An insulated (ceramic) counterpressure bar 17 or 18 is mounted near each
cathode-supporting arm 6 or 7 respectively. These can e.g. be tilted upwards out of
and away from the bath for the purpose of making the bath surface easily accessible
when starting the apparatus for a new series of wires. The cathode-supporting arms
6, 7 are each coated with a wear-resistant layer 19 as sliding contact for the transmission
of current to the wires.
1. Apparatus for the continuous electrolytic treatment of wire-shaped objects (2) comprising
an electrolyte bath (1) and means for conducting the objects (2) predominantly horizontally
through the bath (1) past a succession of anodes and cathodes, wherein the objects
(2) follow a zigzag path of travel in sliding contact with the successive current-transmitting
electrodes (5, 19) that are immersed in the electrolyte and connected to one and the
same pole (14) of the power source characterized in that the supporting arm parts
(6, 7, 8) for said electrodes, each extending horizontally across the bath, thereby
carrying a number of said electrodes (5, 19), are also immersed under the surface
(3) of the electrolyte bath.
2. Electroplating apparatus in accordance with claim 1, characterized in that said electrodes
(5, 19) are connected as cathodes.
3. Electrolytic pickling apparatus in accordance with claim 1, characterized in that
the electrodes (5, 19) are connected as anodes.
4. Apparatus in accordance with claim 1, characterized in that the electrodes (5, 19)
comprise a wear-resistant metal alloy at the sliding contacts.
5. Apparatus in accordance with claim 2, characterized in that the successive anodes
(4, 12) between each pair of cathodes (6, 7, 8) comprise channel-shaped recesses (15)
at the paths of travel of the objects.
6. Apparatus in accordance with claim 5, characterized in that the anodes are inert.
1. Vorrichtung zur kontinuierlichen elektrolytischen Behandlung drahtförmiger Objekte
(2), umfassend ein Elektrolytbad (1) und Mittel zum Führen der Objekte (2) überwiegend
horizontal durch das Bad (1) an einer Aufeinanderfolge von Anoden und Kathoden vorbei,
wobei die Objekte (2) einem Zickzack-Laufweg in Gleitkontakt mit den aufeinanderfolgenden
stromübertragenden Elektroden (5, 19) folgen, welche in das Elektrolyt eingetaucht
und mit ein und demselben Pol (14) der Stromquelle verbunden sind, dadurch gekennzeichnet,
daß die Haltearmteile (6, 7, 8) für die Elektroden, die sich jeder horizontal quer
zum Bad erstrecken und dabei eine Anzahl der Elektroden (5, 19) tragen, ebenfalls
unter die Oberfläche (3) des Elektrolytbads eingetaucht sind.
2. Elektroplattiervorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Elektroden
(5, 19) als Kathoden angeschlossen sind.
3. Elektrolytische Beizvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Elektroden
(5, 19) als Anoden angeschlossen sind.
4. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Elektroden (5, 19) eine
verschleißfeste Metallegierung an den Gleitkontakten umfassen.
5. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß die aufeinanderfolgenden
Anoden (4, 12) zwischen jedem Paar von Kathoden (6, 7, 8) kanalförmige Ausnehmungen
(15) bei den Laufwegen der Objekte umfassen.
6. Vorrichtung nach Anspruch 5, dadurch gekennzeichnet, daß die Anoden inert sind.
1. Appareil pour le traitement électrolytique continu d'objets (2) en forme de fil, comportant
un bain d'électrolyte (1) et des moyens pour faire passer les objets (2), principalement
horizontalement, à travers le bain (1) devant une succession d'anodes et de cathodes,
appareil dans lequel les objets (2) suivent un chemin en zigzag en contact glissant
avec les électrodes successives (5, 19) de transmission du courant qui sont immergées
dans l'électrolyte et sont reliées à une seule et même borne (14) de la source d'énergie,
appareil caractérisé par le fait que les pièces (6, 7, 8) formant bras supports pour
lesdites électrodes, qui s'étendent chacune horizontalement en travers du bain, et
portant un certain nombre dedites électrodes (5, 19), sont également immergées sous
la surface (3) du bain d'électrolyte.
2. Appareil d'électroplacage selon la revendication 1, caractérisé par le fait que lesdites
électrodes (5, 19) sont reliées en tant que cathodes.
3. Appareil de décapage électrolytique selon la revendication 1, caractérisé par le fait
que les électrodes (5, 19) sont reliées en tant qu'anodes.
4. Appareil selon la revendication 1, caractérisé par le fait que les électrodes (5,
19) comportent un alliage métallique résistant à l'usure aux contacts glissants.
5. Appareil selon la revendication 2, caractérisé par le fait que les anodes successives
(4, 12) situées entre chaque paire de cathodes (6, 7, 8) présentent des niches (15)
en forme de canal sur les chemins des objets.
6. Appareil selon la revendication 5, caractérisé par le fait que les anodes sont inertes.