US3368959A - Apparatus for producing an endless sheet of electrolytic copper - Google Patents

Description

Feb. 13, 1968 A. PEDONE 3,368,959

APPARATUS FOR PRODUCING AN ENDLESS SHEET OF ELECTROLYTIC COPPER Filed Nov. 18, 1963 INVENTOR. ,4 V600 yr BYJb/q/w United States Patent Ofi ice 3,368,959 Patented Feb. 13, 1968 3,368,959 APPARATUS FOR PRODUCING AN ENDLESS SHEET F ELECTROLYTIC COPPER Antonio Pedone, Vivaio St., Milan, Italy Filed Nov. 18, 1963, Ser. No. 324,574 2 Claims. (Cl. 204--202) ABSTRACT OF THE DISCLOSURE This invention relates to an apparatus for continuously producing a strip of electrolytic copper, including an electrolyte tank, a travelling endless belt conveyor-like cathode having an upper and a lower substantially horizontal strands and an external surface of the lower strand immersed in the electrolyte for continuously depositing thereon copper by electrolysis as said surface is moved in immersed condition along said tank and an inner sur face opposite to said external surface, means to move said belt conveyor-like cathode, anodes disposed in said tank in proximity of said immersed external surface, means for continuously stripping the deposited copper in the form of band from said belt conveyor-like cathode.

The present invention relates to an apparatus for producing an endless sheet of electrolytic copper.

Up to the present, very long and thin copper sheets have been produced by rolling cast copper plates. This process has several drawbacks, among them the following:

The copper is somewhat contaminated duringthe casting process, and therefore 99.99% purity cannot be obtained, as achieved with the electrolytic system.

In the rolling process, the in-products are bars of considerable thickness, which are reduced to thick plates, from which the thin sheet is obtained after repeated passes of the same between the cylinders of the rolling mill.

The thin sheet thus obtained is composed of copper fatigated by the very high pressures exerted to reduce the thickness in such a great extent; therefore, the material requires further treatment before being ready for utilization in its different applications.

The main object of this invention is to obtain an apparatus which can produce electrolytically a practically endless copper sheet, of the desired thickness, having the referred maximum percentage of purity, that can be utilized without requiring any further treatment.

Another fundamental object of this invention is to provide the referred apparatus With large anodic and cathodic working surfaces, in order to achieve a greater production, in terms of pounds of electrolytic copper sheet, without requiring higher consumption of electrical energy per pound.

In order that the present invention may be more clearly understood, one of its preferred embodiments is shown schematically, as a non-limitative example, in the accompanying drawing in which:

FIGURE II, a lateral view in elevation and longitudinal section, showing the general arrangement of the different component parts of the apparatus.

FIGURE 2, a cross section view.

FIGURE 3, a partial view of FIGURE 2, in enlarged scale.

FIGURE 4, a cross section view of one of the copper anodes, and

FIGURE 5, a partial view of FIGURE 2, showing an alternative arrangement of the electrolyte stirrer.

Same reference characters indicate similar elements or component parts throughout the figures.

The apparatus consists of a movable cathode A formed by an endless conducting belt conveyor-like band a, made,

for example, of stainless steel, extending over and between two cylindrical drums b-c that have horizontal shafts 1 placed in the same horizontal plane, whereby the upper and lower rectilinear sections 2 and 3 of the belt conveyor-like band are arranged horizontally. The drums are mounted on shafts 1, which in turn are rotatably mounted with their ends on corresponding supports, and one of them or both are connected-to conventional driving means, for example, an electric motor, through a speed reducing mechanism.

Both drums bc are somewhat narrower than the width of band a, in order to leave their both edge portions free; said edge portions being provided each with a side wall member d that is elastically flexible and projects perpendicularly from the inner surface of the band. This side wall member is made of a non-conducting material, such as rubber or a plastic.

The lower rectilinear section or strand 2 of the band is arranged inside a cell e containing the electrolyte f; the maximum level of the electrolytic charge does not reach the tops of side wall members d in said lower section, and therefore the side wall members act as containing walls preventing the electrolyte to cover the inner surface of band a, Which remains uncovered, not contacting the electrolyte.

The purpose of this particular arrangement is to utilize the entire inner surface of said lower section 2 of band a for making contact with the negative pole of the direct current electric power supply, and therefore prevent concentration of the density of current at a point of said strand.

A plurality of brushes g make sliding contact with this band inner surface, and are connected to the negative pole, each brush being formed, for example, by a roll 4 of flexible copper strip wound around a flexible steel tube 6; said rolls are aligned in rows arranged at right angle With the band, and the rolls of each row are conductively fixed with their first turn to a common conducting bar 5 which supports and supplies them With electric current.

Each copper roll 4 is slack in order to render it flexible, thus ensuring maximum and continuous contact between the roll and the band; said contact is maintained by the weight of the flexible steel tube 6 around which are wound the rolls of each row, and presses their lower portion against band a.

The quantity of such rows depends on the length of said lower rectilinear section 2 of band a.

The electric current passes to bars 5 and through brushes g is distributed over the inner surface of section 2 of band a.

The copper that will deposit electrolytically over the band can come out from the electrolyte f itself or be emlitted by copper anodes h placed at the bottom of cel e.

In the first case, the cell bottom 7 is lined with a lead lining 8 acting as an insoluble anode, and the electrolyte is a solution of copper salts, its concentration being maintained substantially constant by means of a recirculation system that dosifies it from outside the cell.

In the second case, the cell bottom is lined with a lining 8 that distributes the positive current to a plurality of copper anodes h which emit the copper that deposits on band a.

Said anodes are constituted by copper plates seating through their flat lower surfaces on the lead lining 8 at the cell bottom 7, their upper surfaces being parallel and facing the outer surface (in contact with electrolyte) of the lower section 2 of band a. The upper surface of each anode has a plurality of parallel and uniformily spaced grooves arranged transversally to the band, which define projections 10 having acute tops 10' (FIG. 5),

through which the electric current comes out towards the band, according to the well known pin effect.

Consequently, copper is emitted from said tops uniformily across the upper face of each anode, in a somewhat fan like fashion and migrates towards the band, across the mass of electrolyte.

In order to avoid excessive tauting of the band to prevent sagging of its lower section 2 due to its own weight, a non-conducting supporting rail 12 (FIG. 3), made of plastic material for example, is provided at each lateral wall 11 of cell 2, adjacent to each longitudinal edge of said lower section. The rail is formed by a large and rigid wing that projects from the inner side of said wall, its top face providing a sliding race for the adjacent marginal portion of band a.

The hand does not rest directly upon said race, but through a portion of the body of the side wall member d applied at the band edge, which acts like a skate 13 projecting from its lower surface.

The rail 12 extends somewhat further from said skate, underneath said marginal portion of the band and is uniformly spaced from same, whereby it actuates as a screen interposed between this portion and the copper anodes h, precluding a strai ht path of cations emitted by the anodes and migrating towards said portion, and forces them to pass next to the intermediate zone of the band, before reaching the marginal zones, whereby some of said cations adhere to said intermediate zone, and the rest to the marginal zones.

Thus, concentration of cations, by pin effect, over the band edges, acting in this case as pins, is prevented; therefore, over-thickness of the marginal zone of the copper coat formed over the band is prevented.

A stirrer i for the electrolyte is provided underneath the lower section 2 of the band, in order to disperse the anions and cations travelling across the electrolyte.

The stirrer is formed by a plurality of parallel blades 14 arranged transverse to the band, and fixed through their ends to two posts 15, one arranged at each lateral wall of cell c.

The stirrer is located parallelly in a horizontally plane, underneath the lower section of the band, and is longitudinally slidably mounted, for oscillating movement, in corresponding guides of the cell, each guide being formed by one of said rails 12 that support the lower section of the band, and by another rail 16 (FIG. 3) located underneath the latter; said posts of the stirrer slide in between these two rails.

One end of said stirrer i is connected to means (not illustrated) that drive it with an oscillating motion.

The stirrer is made of a non-conducting material, such as plastics or wood.

A device j is arranged above the upper rectilinear section 1 of band a, for removing the anhydrous copper sulphate that remains on its external surface.

This device 1' is composed by at least one brush 17 having hard bristles, made for instance of steel, and is applied under certain pressure on said external surface of the copper, over which it oscillates in a transverse direction, mounted in related guides and connected to driving means (not illustrated).

A brush having soft bristles 18 is located behind said brush with hard bristles 17, in order to clean from the external surface of the copper coat, the material removed by the first brush 17, and displace it towards the band edges.

This brush oscillates in a transverse direction relative the band a, mounted in corresponding guides, and connected to driving means (not illustrated).

The referred copper coat is detached from hand a at the portion where the latter starts curving over the second drum 0 on its way towards the cell c, and is guided by a free rotating cylinder 19 towards a reel 20 where it is wound forming a roll that is ready for utilization in different applications.

Before reaching reel 20, the copper sheet passes through a hardening device k and a device I for trimming its edges.

The hardening device k is formed by a cylinder 21 for supporting the sheet, upon which several frictioning arms 22 press, said arms being angularly displaceable around a horizontal shaft 23 parallel to the cylinder, and yieldingly pressed thereagainst under the force of related traction springs 24.

The shaft 23 on which said frictioning arms 22 are mounted, is in turn mounted on related guides arranged parallel to the sheet, in order to allow simultaneous angular displacement of said arms over the sheet, with an oscillating motion, said shaft being connected to driving means (not illustrated).

The trimming device 1 comprises a cylinder for sup porting the band and two circular rotating shears, one related to each marginal zone of the copper sheet.

According to an alternative arrangement, the stirrer is composed by two sets of blades, one next to each lateral wall 11 of the cell c; each of said blades 14 is formed by a lateral arm projecting from a vertical shaft 25 rotatively mounted on related supports 25a on the lateral adjacent wall 11 of the cell e. The top portion of said shaft which projects above the cell, has a short rod 26 articulated at its free end to a crank 27 that is common for all the blades located next to the same wall of the cell (FIGS. 3 and 6).

Both cranks 27 are related through adjacent ends to means that drive them with oscillating motion.

No doubt that in the embodiments of this invention, some modifications can be introduced in details of construction and shape of the apparatus for producing endless electrolytic copper sheet, but never departing from the fundamental principles set forth in the following claims.

What is claimed is:

1. An apparatus for continuously producing a strip of electrolytic copper, including an electrolytic tank, a travelling endless belt conveyor-like cathode having an upper and a lower substantially horizontal strands and an external surface of the lower strand immersed in the electrolyte for continuously depositing thereon copper by electrolysis as said surface is moved in immersed condition along said tank and an inner surface opposite to said external surface, means to move said belt conveyorlike cathode, anodes disposed in said tank in proximity of said immersed external surface, means for continuously stripping the deposited copper in the form of band from said belt conveyor-like cathode, and wherein the improvement comprises said belt conveyor-like cathode in the form of horizontally extending endless stainless steel belt having side-wall members of non-conducting elastic material at each edge thereof, said side-wall members having each a portion extending in a direction substantially perpendicular to said belt cathode thereby to project from said inner surface and another portion extending substantially parallel to said belt cathode, said another portion having a slot adapted snugly to receive the edges of said belt cathode, thereby preventing the electrolyte to reach said inner surface and an edge portion of said external surface when said external surface is immersed into the electrolyte, two horizontally spaced drums at the end of said travelling belt conveyor-like cathode for winding said belt cathode about said drums, a plurality of electric contact members in contact with said inner surface, said electric contact members extending over the entire operative width of said belt cathode and being arranged at regular intervals in the longitudinal direction of the belt cathode and agitating means between said cathode belt and said anodes.

2. An apparatus according to claim 1, wherein said electrolyte tank has on the bottom thereof a bed of lead and wherein said anodes are slabs of copper placed on said bed of lead.

(References on following page) References Cited UNITED STATES PATENTS Eustis 204-13 Demel 20413 Yates 204-13 Hall 204-206 Venable 204206 Sternfels 204-216 FOREIGN PATENTS 8/1953 France. 9/1953 France.

HOWARD S. WILLIAMS, Primary Examiner.

JOHN H. MACK, Examiner. Brietzke 15 -94 10 W. VAN SISE, Assistant Examiner.

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