US2317242A - Plating tank for electrodeposition of metals on metallic strip - Google Patents

Description

April 20, 1943. w.s. ALLEN' ETAI.

cTRobEPosITIoN oF METALS oN METALLIC STRIP PLATING TANK FOR ELE Filed April 28, 1939 3 Sheets-Sheet l I April 20, 1943. w. s. ALLEN ErAL PLATING TANK FOR ELEGTRODEPOSITION OF METALS ON METALLIC STRIP Filed April 28, 1939 5 Sheets-Sheet 2 April 20, 1943.

w. s.lA|.LEN ETAL PLATING TANK FOR LECTRODEPOSITION OF METALS ON METALLIC STRIP Filed April 28, 1939 5 Sheets-Sheet 3 FIEQE.

MN@ ,f m5 A ,/V i@ mi@ t /Mmra @2 M5 @5.0% ,Wd

FIEL-4.

Patented Apr. 20,` 1943 UNITED STAT- Es' Pri'rr'zlvrV OFFICE PLATING TANK FOR ELECTRODEPOSITION F METALS ON METALLIC STRIP william s. Anmriusburgh, mama- A. mmon,

Dormont, and Ewart Another lobject of the present invention is to 4provideganilriproved tank for electrodepositing metalso metallic strip in which the strip is so positioned Vand 'the'electrolyte so circulated thereabout .-a sto provide an improved electrodeposited surface onqthe resultant product.

' A further object of the present invention resides in vertically positioning the anodes so that they ,are readily removable and capable of rearrangement across the width of the strip being .plated to provide uniform deposition of the metal upon the surfaces of the strip. u

A still further object of the present invention l resides in providing a plating tank with aplurality of vertical pass lines whereby trappage of foreign matter on the surfaces of the strip material is minimized. V

Other objects and advantages will become apparent as the description proceeds and reference is had to 'the accompanying drawings, in which:

Figure 1 isa sectional elevation of the apparatus of the present invention;

Figure 2 is a sectional elevation on the line lI-II of Figure 1; 4,

Figure 3 is a top plan view of the tanks show ing the overiiow system; and

'Figure 4 is a fragmentary side elevation of Figure 3. In the drawings, the numeral 2 represents a plating tank which includes side walls and -a divided bottom portion. The bottom portion of the tank is so constructed and arranged as to include sloping side walls 3, the purpose of which isto direct any sediment downwardly so as to collect in the bottom of said tank, wherebyy such sediment maybe easily withdrawn from said tank through the outlets 5. The top portion of the tank is offset outwardly from the side walls by a ange 6 with the upwardlyextending flange 1 forming a trough at each end of the tank- These troughs form, in combination with overflow chambers to be subsequently specifically described, an overflow system necessary for the circulation of the electrolyte.

1 Positioned within the tank are segmental baille members 8 adapted to divide the interior portion v .if the tank into a plurality of separate chambers or compartments. Within four of these com- S. Taylerson. Pittsburgh, Pa., assignors to Carnegie-Illinois Steel Corporation, a corporation of NewJei-sey v `mutation Amica-1939, serial No. 219,102

1 claim. (ci. coi-gos) partments or chambers are positioned removable anodes 9 so as to provide four active vertically positioned plating areas through which the continuous strip material is moved in sequence. Between each. oivthe active compartments is an inactive compartment containing electrolyte, but in which no plating reaction is effective upon the strip material. Positioned within two of the inactive compartments is a rubber covered pipe 26, the purpose of which will be subsequently explained. The anodes are supported, by a bridge l0 extending across the top of the tank, in such a manner as to be readily removed from and/or rearranged across the plating tank if, when and as desired, to maintain eicient plating of the continuous strip. The

p feature of readily removing and/or rearranging the anodes as desired is of the type speciically shown ,and describedin application Serial No. 270,708 entitled Method and apparatus for supporting and replacing anodes and led April 28, 1939, in the name of Ewart S. Taylerson.

A supporting frame I6 is positioned above the plating tank and is provided with bearing brackets I1 which support conductor rolls I8. These conductor rolls may besupported, in any conventional manner, within the bearing brackets. The conductor rolls are preferably provided with a hard metallic protectivesurface or coating such as chromium and the like, and may be cooled, in any conventional manner, by circulating water throughout its interior. The connection between the conductor rolls and the negative side of the generator (not shown) is established, in any conventional manner, preferably by means of resiliently mounted electrical brushes, as disclosed in application Serial No. 270,706 entitled Electrical conductor and iiled April 28, 1939, in the name of Ewart S. Taylerson.

The strip, in passing over the conductor rolls, is established as the' cathode. In order that the best possible electrical contact may be maintained between the conductor roll and the strip, holddown rolls I9 are provided. The'hold-down rolls I9 are pivotally supported from a flange on the bearing bracket l1 by arms 20.

.The hold-down rolls through the action of the turnbuckle arrangement 2l press the strip into positive contact with said conductor rolls. In order to facilitate threading of the machine,

. the turnbuckle arrangement 2|, at its point of attachment to theA arm 20 is provided with a disengaging mechanism consisting of an eccen-- the arms 20 and operating within an eccentric strap 22 connected to the turnbuckle 2l. The shaft 23 is provided with a hand-lever at one end thereof, and when this hand-lever is rotated the hold-down roll is moved either away from or into contact with metallic strip passing over the conductor roll. Disengagement .of the holdidown roll permits initial threading of the strip material over said conductor rolls. When the hold-down roll is engaged, it establishes a positive contact between said conductor rolls and strip material. In establishing the desired positive contact, the hold-down roll is locked in position by the disengaging mechanism.

In additionvto the hold-down roll I9, the entryV conductor roll I8* is provided with a squeegeeV roll I8, which roll prevents excess liquids carried on the surfaces of the strip from previous processing steps. from being carried into the plating bath.

Sink rolls I3 are provided in the bottom of the plating tank and cooperate with the conductor rolls to form pass lines for the strip material.

.The sink rolls I3 are so positioned with respect to their cooperating conductor rolls that the distance from the center of a sink roll to the center of either of its cooperating conductor roll is, when measured in a horizontal plane, the sum of the radius of the sink roll and the radius of the cooperating conductor roll. Thus, the pass line of the strip between the rolls is in a vertical plane.

The sink rolls I3, which are rubber covered, are supported in the bottom of the tank in any conventional manner, and may be of conventional design. These rubber covered sink` rolls are mounted, in any conventional type bearing supports, which may be either internal or external bearings and are of such a construction'as to preclude entrance of the electrolyte within the bearing structure. Positioned within each sloping bottom portion 3 are several spaced guide plates 3, so shaped as to conform to thslopingl plating tank. These spaced 'guide plates 3'i are provided at their bottoms with a cut-out portion which permits the electrolyte to be drained when desired through the outlet pipes 5. Mounted in any conventional manner on the side of the plating tank ladjacent the sloping bottom portions at spaced positions are rubber covered supports I2 adapted to serve as bearing supports for the closed ends of tubes I4, while the other ends of said tubes are supported by the opening which connects withthe inlet feed pipe for the electrolyte. These tubes are provided with an open- Ml in order that the electrolyte may circulate upwardly -within the active chambers or compartments formed by the segmental baille members. The flow of electrolyte which is directed upwardly passes on both sides of the continuous strip. Attached to the walls of the respective chambers within the tank are trough-like members I5 provided at the bottom oi.' each chamber containing -caught by said trough-like members I5 and prevented from dropping down between the strip material and the sink rollsl. The'trough-like members I5 also serve to protect the'tubes I4 from damage should an anode be dropped during anode renewal or rearrangemen-t on the anode supporting bridge. 4 1

Secured on each side of the tank are two preformed rubber covered metallic members iorming overflow chambers 25. These overflow chambers 25 extend upwardly from the side walls of the tank to a point in substantial alignment with the upper edge of the flange l. A rubber covered pipe 26 which extends through the inactive pass chambers at a point adjacent the bottom of the overflow chambers 2,5, as previously described. connects the-overflow chambers on each side of the tank so that the electrolyte may-be withdrawn from the plating tank through the pipe 21. The electrolyte may then be settled, filtered, cooled or heated as desired, in any conventional manner, and returned by pumps or any other conventional apparatus to the pipes I4 for recirculation within the lplating tank. y

In operation of the present invention, the strip indicated generally as at S is fed from a previous processing device such, for example, as a washer or brushing machine and fed over the entry conductor roll I 8, To initially permit threading of the strip material into and through the plating tank, the eccentric mechanism hereinabove described, is operated to release the hold-down rolls I9 so that the strip may be fed over and around the major portion of the `entry-conductor roll from which position it passes vertically downward into the pass line generally indicated at A between the anodes 9. As the strip is initially fed downward through the initial pass line A, it comes into contact with the guide members 3 provided at spaced intervals in the sloping bottom of the plating tank, which guide members serve to direct the strip material around the rst sink roll I3 and cause the same to move upwardly into Ithe bottom portion of the pass line indicated generally atv B. It is then pulled upwardly through the pass line B, passed over the second conductor roll and subsequently moved downwardly in a vertical plane through the pass line C, is guided around the second sink roll and up into the bottom of the pass line D, from whence itis pulled upwardly and over the last conductor roll and entered into further processing apparatus.

After this initial threading of the strip material, the hold-down rolls are moved into position to establish positive contact between the strip material and the conductor rolls. The electrolyte is then fed into the plating tank through the pipes Il and upward circulation is established in the pass lines A, B, C and D on each side of the strip. The coating operation can now be started by simultaneously closing the electric circuits for supplying the necessary current for the plating operation and establishing movement of the.

material through the plating bath.

While we have shown and described a specific' In aplating 'tank for"electroplating 'metallicstrip, means for establishing the strip" as the cathode, means for moving the strip in a substantially vertical path, a plurality of spaced vertically extending anodes within said tank, means below the bottoms of said anodes for positively circulating the electrolyte upwardly on either side of the strip, said last-named means including a pair of spaced parallel horizontally extending pipes having on the adjacent sides thereof orices for the distribution of electrolyte. and

guard means between said last-named means and the bottoms of said anodes for preventing damage by the accidental dropping of the latter.

WILLIAM S. ALLEN. RICHARD A. DIMON. EWART TAYLERSVON.

Images