US2554943A - Electroplating apparatus - Google Patents

Description

y 1951 Q. B. FARMER 2,554,943

ELECTROPLATING APPARATUS Filed Oct. 25, 1945 I "unnfluunun'nunuunflnnnnuuHunu-nn-uunnun 2 Sheets-Sheet l y 29, 1951 Q. B. FARMER 2,554,943

ELECTROPLATING APPARATUS Filed Oct. 25, 1945 2 Sheets-Sheet 2 F'a tented May 29, 1951 ELECTROPLATING APPARATUS Quentin Boyles Farmer, Dundalk, Md., assignor to Bethlehem Steel Company, a corporation of Pennsylvania Application October 25, 1945, Serial No. 624,388

6 Claims.

i the art of electroplating of steel strip, and more specifically to the proper maintenance of coating uniformity by the provision of a new type of anode.

A'dilficulty often encountered in the continuous electroplating of steel strip is the proper maintenance of a uniform distribution of coating throughout the width of the strip. In the continuous electroplating of steel strip the former commercial practice has been to use a number of fixed parallel anodes, of substantially the same widthy-throughout the length of the plating bath. Such a practice obviously cannot produce a uniform thickness of coating if the width of the strip, as is necessary in commercial practice, is changed from time to time.

When fixed anodes only are used, and where strip which is wider than the fixed anodes is introduced into the plating line, the coating on the edges of the strip will be considerably less in weight than the coating at the center of the strip. Conversely, when strip of a width narrower than the fixed anode is run, the coating Weight. of tin is much greater at the edges than at the center of the strip.

One. object of my invention is to provide a new type of anode which will produce a more uniform coating on the metallic strip.

A second object is to provide an anode which can bereadily positioned in the plating tank.

Another object is to maintain a continuous plating operation regardless of the width of the strip used.

1 Another object is to conserve plating metal.

To aid in the description and to be considered a part of the specification of this invention the following drawings are included:

Figure l is a diagrammatic top plan View shov ing the relative position of the fixed and adjustable anodes of this invention;

Figure 2 is a transverse vertical section of the adjustable anodes on the line 2-2 of Figure 4;

Figure 3 is a detailed partial elevation of the anode adjusting mechanism;

Figure 4 is a partial longitudinal vertical sectionon the line 4-4 of Figure 2;

Figure 5 is a detailed plan view showing roll mechanism upon which the anode moves along the support bar;

Figure 6 is a section of the anode bus bar connection on the line 6-B of Figure 2;

Figure -7 is a section of the anode clamp and support bar on the line 1-1 of Figure 2;

Figure 8 is a section of the anode clamp, sup- 2 port bar and roll means for moving the anode on line 8-8 of Figure 2;

Figure 9 is a section of the anode clamp roll on the line 9-9 of Figure 8.

Referring to the drawings in detail, the numeral Ii represents a plating tank containing a plurality of fixed vertical anodes 12, followed by a series of adjustable narrower vertical anodes l3. The fixed anodes rest on a support M, and the supporting bar 2! for the adjustable anodes rests on a similar support it. The metal strip l5, which acts as the cathode, operates around rolls i? and i8, and enters tank H at [9 and leaves the tank at 25. The strip travels alternately over and under the succession of anodes. Adjustable anodes H, as depicted in Figure l, are arranged in tandem, that is, two anodes on one side of the tank are followed by two on the opposite side of the tank, etc. These adjustable anodes i3 are free to be moved from their location at the side of the tank H to a position wherein the center line of the anode corresponds with the center line of the tank Ii. The adjustable anode I3 is bolted to a connecting clamp 22, at the top of which is located a set of two rolls 23, which operate over a supporting bar 2!. The adjusting mechanism 24 operates the anode i3 backward and forward by means of connecting rod 25. Attached to each anode i3 is a copper bus bar connection 26 carrying a graduated scale which indicates the relative position of anode 13 from its starting position near the side of the tank H. Electric connections 22', for supplying current to anode I3, are attached to bar 28.

For the preferred embodiment of the invention I shall describe the use of adjustable anodes in an electrolytic tin-plating line, wherein soluble tin anodes are used to plate steel strip having a width greater than that of the anodes. Thirty two fixed soluble tin anodes, 28 inches wide, are placed in alignment in the plating tank and spaced from each other at a distance of 8 inches. The'anodes are 8 feet high and 4 inches thick. Beyond the first group of 32 anodes are 8 more fixed anodes, 26 inches wide, and spaced 8 inches apart. At the exit end of the tank are placed 8 adjustable soluble tin anodes, also spaced at a distance of 8 inches. The fixed anodes, having the shape of a rectangular prism, are aligned in the tank so that the wide, or main, faces are in parallel relationship, with the narrow faces opposing opposite sides of the tank. The adjustable anodes 8 feet, 9 inches high, 4 inches thick and 12 inches wide, are arranged in tandem, two anodes on the left side of the tank followed by two on the right side, two more on the left and finally two on the right. The fixed anodes are molded so as to carry a projecting ear on each side at the top of the member, The ears rest on a support 28, built into the side of the tank and thus hold the anode in position. The adjustable anodes, as previously described, are bolted to a connecting metal clamp, the clamp carrying a roll mechanism at the top. The rolls, in operating over the support bar 2|, permit the anode tohave free movement backward and forward through its path of travel, that is, reciprocally, for a distance of 12 inches, from the side of the tank to the center of the tank. As shown in the drawings a motor driven moving mechanism, connected to the anode by means of a connecting rod, can be used to place the anode at any desired point within its limit of travel. The distance of travel of any adjustable anode includes that distance from a point at which the outer edge of an adjustable anode, at one side of the tank, extends beyond the corresponding edges of the fixed anodes to a point at which the vertical center line of the adjustable anode is in substantial alignment with the vertical center line of the tank. If preferred, the anodes can be moved by hand.

In operating the continuous plating line, the metal strip to be plated, after having been cleaned and rinsed in any conventional manner, said strip acting as the cathode, is introduced into the tank under the first bottom roll, passes upwardly in front of the first fixed anode, over the first top roll, there downwardly between the first and second fixed anodes and equidistant from them. From there the strip passes under the second bottom roll and thence between each successive anode. The top rolls act as contact rolls. The strip is aligned so that the center line of the strip is coincident with the center line of the fixed anode.

To compensate for variations in coating weight, adjustable anodes are arranged in the tank as outlined above. As the adjustable anodes can be moved to any desired position from one side of the tank to the center of the tank, and as there are four adjustable anodes operating from one side of the tank and four anodes from the opposite side, sufilcient adjustment can be made to provide for a uniform distribution throughout the width of the strip. The outer edge of the adjustable anode, when in its starting position at the edge of the tank is several inches beyond the corresponding edge of any of the fixed anodes to compensate for wide strip. In order to aid the operator in locating the anodes at the proper'distance from the side of the tank, a copper bar, which is attached to the anode holding device, carries a scale graduated in inches. This bar passes over the side of the tank and the scale is readily seen b the operator.

When plating strip having a width greater than that of the fixed anode, there will ordinarily be a deficiency of coating on the edges of the strip; in such case the movable anodes will be placed along the outer edges of th sL'rip so that the said outer edges ma receive sufficient additional coating to compensate for the deficiency resulting from the action of the fixed anodes.

Conversely, where the strip is narrower than the fixed anodes the outer edges thereof will be overplated and the central portion will be underplated. In such case the movable anodes will be moved inwardly from the outer edges of the strip so as to plate the central portion of the strip. The position of the movable anodes may be varied, depending on the width of the strip, from a position in which they are located opposite the edges of the strip to an extreme one in which the movable anodes are arranged directly behind each other as shown in dotted lines in Fig. 1.

As a result of the foregoing combination of fixed anodes and adjustable anodes having a width substantially less than that of the fixed anodes I am able to plate uniformly strips having a wide range of widths, With fixed anodes having a width of 28 and adjustable anodes having a width of 12", I can produce a substantially uniform coating upon strip of any width between 18" and 34".

By using the adjustable anodes the variation of coating weight throughout the width of the strip can be held within a range of 0.02 pound of tin per base box, while with fixed anodes alone the range was between 0.04 and 0.06 pound of tin per base box.

By the term fixed anode as used herein, I mean an anode which is fixed against lateral movement in the plating tank.

Although I have outlined a process and apparatus whereby this invention can be used in a tin electroplating line, it is to be understood that the invention should not be so restricted but can also be used in the electroplating of other metals such as zinc, nickel, etc. Further, in the process and apparatus described, soluble anodes have been used, but it is apparent that the invention could be used as well where insoluble anodes are employed.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An apparatus for the continuous electroplating of metallic strip of different widths comprising a tank containing a plurality of vertical anodes aligned in tandem with the main faces of the anodes in parallel relationship, said anodes being fixed against lateral movement and having a width substantially equal to the mean width of the strip to be electroplated and not less than two narrower vertical anodes, one of said narrower anodes being reciprocally laterally adjustable from one side of said tank to a point at which the vertical center line of the anode is in substantial alignment with the vertical center line of the tank and another of said narrower anodes being reciprocall laterally adjustable from the opposite side of said tank to a point at which the vertical center line of the anode is in substantial alignment with the Vertical center line of the tank, said narrower anodes having a width less than one-half the width of the fixed anodes, means to reciprocally laterally adjust the narrower anodes and means to movethe strip between and past the anodes. Y

2. An apparatus for the continuous electroplating of metallic strip comprising a tank containing a plurality of vertical anodes aligned in tandem with the main faces of the anodes in parallel relationship, said anodes being fixed against lateral movement and having a width substantially equal to that of the strip to be electroplated, followed by a series of narrower, laterally adjustable, vertical anodes, pairs of said adjustable anodes being aligned in tandem, alternately on opposite sides of the tank, means to reciprocally laterally adjust the adjustable anodes and means to move the strip between and past the anodes.

3. An apparatus for the continuous electroplating of metallic strip comprising a tank containing a vertical anode, said anode being fixed against lateral movement and having a width substantially equal to that of the strip to be electroplated followed by a series of narrower, laterally adjustable vertical anodes, pairs of said adjustable? anodes being aligned in tandem alternately on opposite sides of the tank, means to reciprocally laterally adjust the adjustable anodes, and means to move the strip between and past the anodes.

4. An apparatus for the continuous electroplating of-metallic strip of diilerent widths comprising a tank containing a Vertical anode, said anode being fixed against lateral movement and having a width substantially equal to the mean Width of ,the strip to be electroplated, and not less than two narrower vertical anodes, one of said narrower anodes being reciprocally laterally adjustable from one side of said tank to a point at which7the vertical center line of the anode is in substantial alignment with the vertical center line of the tank and another of said narrower anodes being reciprocally laterally adjustable from theopposite side of said tank to a point at which the vertical center line of the anode is in substantial alignment with the vertical center line of the tank, said narrower anodes having a width less than one-half the width of the fixed anodes, means to reciprocally laterally adjust the narroweranodes and means to move the strip between and past the anodes.

5. An j apparatus for the continuous electroplating of metallic strip of different widths comprising a tank containing a plurality of vertical anodes aligned in tandem with the main faces of the anodes in parallel relationship, said anodes being fixed against lateral movement and having a width substantially equal to the mean width of the strip to be electroplated and not less than two narrower vertical anodes, one of said narrower anodes being reciprocally laterally adjustable from a point at one side of said tank at which its outer edge extends beyond the correspondingli edges of the fixed anodes to a point at whichf'the vertical center line of said narrower anode isfin substantial alignment with the vertical center line of the tank and another of said narrower anodes being reciprocally laterally adjustable from a point at the opposite side of said tank at which its outer edge extends beyond the corresponding edges of the fixed anodes to a point' 'at which the vertical center line of said narrower anode is in substantial alignment with the vertical center line of the tank, means to reciprocally laterally adjust each of the narrower anodesg'lietween a point at which its outer edge extends beyond the corresponding outer edges of the fixed anodes to a point at which its vertical center line is in substantial alignment with the vertical center line of the tank, and means to move the strip between and past the anodes.

6. An apparatus for the continuous electroplating of metallic strip of dillerent widths comprising a tank containing a vertical anode, said anode being fixed against lateral movement and having a width substantially equal to the mean width of the strip tobe electroplated, and not less than two narrower vertical anodes, one of said narrower anodes being reciprocally laterally adjustable from a point at one side of said tank at which its outer edge extends beyond the corresponding edge of said fixed anode to a point at which the vertical center line of said narrower anode is in substantial alignment with the vertical center line of the tank and another of said narrower anodes being reciprocally laterally adjustable from a point at the opposite side of said tank at which its outer edge extends beyond the corresponding edgefof the fixed anode to a point at which the vertical center line of said narrower anode is in substantial alignment with the vertical center line of the tank, means to reciprocally laterally adjust each of said narrower anodes between a point at which its outer edge extends beyond the corresponding outer edge of the fixed anode to a point at which its vertical center line is in substantial alignment with the vertical center line of the tank,,and means to move the strip between and past the anodes.

QUENTIN BOYLES FARMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 830,093 Meaker Sept. 4, 1906 895,164 Cowper-Cloles Aug. 4, 1908 1,242,695 Hood Oct. 9, 1917 1,952,762 Levy -et al. Mar. 27, 1934 2,174,071 Grupe "Sept. 26, 1939 2,317,242 Allen'et a1 Apr. 20, 1943 2,382,018 lvla'rtin Aug. 15, 1945 2,395,437 venakble Feb. 26, 1946 2,399,254 Riegler et al Apr. 30, 1946 2,461,556 Lorig Feb. 15, 1949 FOREIGN PATENTS Number Country Date 551,841 Great Britain Mar. 11, 1943 555,431 Great Britain Aug. 23, 1943 OTHER REFERENCES Metal Industry, January 1939, pp. 24, 25, 26 (an article by Haas).

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