US2244423A - Apparatus for strip plating - Google Patents

Description

7 Sheets-Sheet 1 IHVENTOR ATTORNEYS.

W. F. HALL APPARATUS FOR STRIP PLATING Filed June 28, 1938 WAL-ufr F. HAM. BYi/MLM `lune 3, 1941.

` W. F. HALL APPARATUS FOR STRIP PLATIN@ June 3, 1941.

Filed June 28, 1938 7 Sheets-Sheet 2 INVNTOR WESLEY F. HALL.

ATTOR NEYS.

June 3, 1941.

w. F. HALL APPARATUS FOR STRIP PLATING Filed June 28, 1938 '7 Sheets-Sheet 3 Vwwm'oR #6267 EHlL y BY ATTORNEYS.

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June 3, 1941. Aw. F. HALL APPARATUS Fonszmrr PLATING Filed une 28, 1938 '7 sheets-sheet e INVENTOR' WAFJLEY F. HLL

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' ATTORNEYS June 3, 1941. vw, F, HALL APPARATUS PoR STRIP PLATING Filed June 28.11938 v sheets-Sheet 7 |NvEN-roR W5S/.EY F- HLL OQ ATTORNEYS.

Patented June 3, il

ArrAnArUs ron srmr rnA'rrNG wesley F.

Hall, Matawan, N. J., assigner to Hanson-Van Winkle-Munning Company,

Matawan,

N. J., a corporation of New Jersey Application June 2,8, 1938, Serial No. 216,322

6 Claims. (Cl. 2204-209) An object of this invention is toV provide an apparatus and method oi treating strip material on one side at a time, the other side being held against rolling electric contacts and seals of rubber or equivalent resilient synthetic resinous materlal. In place of the electrical contact rolls other means of conducting the current to the strip material may be used, such as direct contact brushes or traveling flexible metallic belts. The rolling contacts are, however, preferable since they provide means for supporting and guiding the strip material through the apparatus as well as affording a suitable low friction contact with the strip being treated. A

Another object is to provide a device of'this type wherein by means of the novel construction it is possible to use jhigh current densities, for instance 500 to 1000 amperes per square foot or higher in the ele'ctrolytic treatment of strip material'.

AnotherA object of this invention is to protect thefedge of the strip being electroplated by yielding rubber backing or equivalent resilient electrical insulating material which is not attacked byv the'electrolyte. This prevents or greatly reduces the tendency to build up thicker coatings on the edges of the strip than in the central portion, which is a well known common fault of prior strip plating apparatus.

Another object of this invention is to provide an apparatus for electroprocessing metal wherein the metalis electrochemically treated with an electrolyte while current is supplied to the strip by means vof dry electric rolling contacts.

Another "object is to provide a method and apparatus for the alternate electrofprocess treating of moving metal strip or strips on one side and then on the other while continuously moving the metal strip and electrolyte.

Another Objectis to provide an apparatus for supporting and moving continuous metal strips into contact with an electrolyte and maintaining electricalv contact with the metal strip adjacent the electrolyte but out of contact therewith.

Another object is to provide means for subjecting the metal being electroprocessed to large currents of electricity while the metal is continuously moved through the electroprocessing apparatus. y

Another object is to provide an apparatus which makes it, possible to use higher current densities in electrochemically cleaning and plating strip material than heretofore employed.

A still further object is to provide electroplating apparatus wherein the electrical contactto the strip or material being plated is maintained at all times out oi contact with the electrolyte to effect dry electrical contact on the side opposite that being plated.

Heretofore where one side onlyl of a sheet of material was to be tin coated or otherwise Plated the other side was coated with asphaltum or some other insulating varnish before immersion in the electrolyte. After the material had been electroplated the insulating coating on the opposite side was removed by a suitable solvent before heat treating the plated, coating. By employing the apparatus and method i'or cleaning and electroplating strip material of this invention a product is obtained having a more uniform and superior coating than has heretofore been attained. Moreover the use of insulating coatings for protecting parts not to be'plated with their attendant removal is eliminated. y

Aside from the above mentioned improvements attained by this invention, very high current densities may be satisfactorily employed in electroprocessing materials by this invention. 'I'his is desirable since the electrocleaning and plating of the material can beeiected in a much shorter time, increasing production with consequent lowering of electroplating costs.

The maximum current densities recommended heretofore for tin plating are of the order of -amperes per square foot. By the novel arrangement of this invention, however, unexpected high current densities on the order of 500 to 1000 amperes and higher can be used satisfactorily, particularly for tin plating thinvmetal strips.

This application is related to my copending applications No. 219,619, tiled July 16, 1938, and No 281,681, led June 28, 1939. The latter is a continuation in part of application No. 219,619.

A related machine for electroplating strips or ribbons oi' material is disclosed in my co-pending application, Serial No. 281,682, led June 28, 1939.

Referring to the drawings:

Figures 1 and 1A are diagrammatic side elevation views showing the complete electroprocessing .gli

apparatus of this invention. It will be understood that this arrangement is merely illustrative and is not intended to limit the disposition of the different treating compartments, electrolytes or the sequence of treating the strip ma-l terial;

Figures 2 and 2A are plan views of the preferred arrangement of the complete apparatus as illustrated in Figures 1 and 1A;

Figure 3 is a vertical section view through the apparatus taken along the line 3--3 of Figure 2;

Figure 4 is a vertical section taken along the line 4 4 of Figure 2;

Figure 5 is a vertical section of a part of the electroplating portion of the machine taken on the line 5-5 of Figure 2, looking in the direction of the arrowsf Figure 6 is a detailed plan view of a portion of the bottom plating section of the apparatus illustrated in Figure 4. The central bus bar is shown in section with certain parts being cut away to show the positioning of the electrolyte return conduits;

Figure 7 is a detailed plan view of the anode arrangement taken on the line 1 1 of Figure 3, looking in the direction of the arrows;

Figure 8 is a detailed vertical section of a part of the electroplating section taken on the line 8 8 of Figure 5;

Figure 9 is a view in' section, partly broken away, taken along the line 9-8 of Figure 8, look ing in the direction of the arrows;

Figure l0 is a detail section view taken on the line iii-I0 of Figure 8, showing the bearing for the supporting roll;

Figure 11 is a detail section view taken on the line II-II of Figure 3 showing the arrangement of the apertured dam 'means in the electrolyte return trough member; Y

Figure 12 is an enlarged sectional view through a portion of the electroplating compartment show.. ing the manner of shielding the edges of the strip by yielding rubber backing.

Referring to the drawings in detail, wherein like reference characters indicate similar parts throughout the drawings:

Figures 1 and 2 show the complete layout o the apparatus for electroprocessing continuous strips of material or pieces to be electroplated in horizontal position. This is the preferred form, but this invention also contemplates treating the strip while maintaining it vertically on an edge or in any other suitable position. It will be also understood that either alkaline or acid electrolyte cleanersmay be employed when desired, and any one or more of the preliminary cleaning steps may be omitted prior to electroplating when it is unnecessary.

General treatment of strip material The material to be treated is drawn through the apparatus from conventional uncoilers with looping towers, welding equipment, etc. and after being electroprocessed and plated is wound up on similar coilers on the delivery end. The strip material I is first passed through an -electrlolytic cleaning compartment 2 whereupon the top side of the strip is subjected to electrochemical cleaning with electrolyte supplied from the tank l adjacent thereto.

The strip then passes through the treating chamber I where the bottom side of the strip is submitted to electrochemical cleaning similar to the top |`side. the electrolyte being supplied to chamber I from tank 5. Thereafter the strip or sheet passes over guide rolls and is subjected to rinsing and brushing by the revolving brushes 6.

Next the strip is treated on the top side with acid pickling solution while passing through the compartment l which is supplied with acid, such as dilute sulphuric or other suitable acid, from the storage tank 8 and thence through the compartment 9 where the bottom side is acid treated in like manner. The acid is-pumped to chamber 9 from the tank I0. The strip is thereafter rinsed and scrubbed as indicated at I I.

In some cases where the metal sheet or strip to be cleaned and plated is coated with a heavy illm of oil, grease or like fatty substance, it may be ilrst subjected to a-solvent degreasing treatment for the removal of the oil and grease from the strip or articles to be plated prior to being electrolytically cleaned and subsequently electroplated. The solvent degreasing treatment may comprise merely the dissolving of the oil and grease by non-inflammable chlorinated hydrocarbon, either in its heated liquid or vapor state. Various chlorinated hydrocarbon solvents may be employed, but trichlorethylene is preferable since it is most readily stabilized for continuous use.

The strip material after it has been thoroughly deoxidized and cleaned so that the Surfaces present a substantially chemically pure metal surface is now ready to be electroplated and is passed into the electroplating chamber I2 where the top side of the strip is made the cathode in a suitable electrolyte containing the metal to be plated on the strip, The electroplating electrolyte solution is supplied to the electroplating chamber I2 from the tank I3. Thereafter the strip is passed into compartment Il'where it is similarly electroplated on the opposite or bottom side by the plating solution pumped from tank Il.

The material, after it has been plated on both sides, is burnished, rinsed and dried as indicated at I C, I1 and II. 'I'he finished material is then delivered to conventional coilers and is ready for shipment or use.

Electroplatina procedure In the electroplating part of the apparatus of this invention the strip is plated on one side at a time and high current densities are employed without the necessity of carrying the current through the strip for a long distance. Provision is also made to prevent excessive concentration of electric current at the edges of the strip with the resultant building up of the deposit along the edges, which is highly undesirable. Ordinarily a comparatively wide and thin strip of material is treated, and only one side is treated at a time. The other side is held against a Acushion of soft rubber or the like resilient material which forms a seal around the edges of the strip.

The back side of the strip is connected to the electric circuit at points closely adjacent to where the current enters the other side from the electrolyte. The electric circuit contact to the back of the strip is preferably made through rollers: however, sliding 'or movable beit contacts, as heretofore mentioned, may be used if desired.

In Figure 3 the strip material I is shown passing through the plating compartment I2 which is supported on the top or side of the electrolytic supplygtank I3 by means of the brackets Il and Il. The plating chamber I1 is provided with a rubber lining 2| which is arranged to contact other rubber portions to seal the outer edges of the strip and aiords a liquid tight chamber on the upper side of the strip. The outer edges of the strip are sealed by a rubber lined adjustable trough 22 enclosing the edges of the strip. The trough 22 is provided with a gutter 23 for collecting electrolyte introduced on top of the sheet or strip.

A rubber walled partition 23a having openings 23h is disposed in the trough 23, as shown in Figure 11, through which the electrolyte passes outward from the plating chamber overflowing into the electrolyte collecting troughs or gutters 23 disposed adjacent the edges of the strip. The slotted partition aids in maintaining the plating compartment completely full of electrolyte during operation to obtain a uniform plating of the strip as it is moved therethrough.

The trough is provided with a lateral inward extension 24 which is covered with a rubber sealing member 25, and the outer portion of the strip engages against this rubber covered extension member 24. This effectively seals the under side of the strip and prevents passage of electrolyte thereunder. Over the top of the trough 22 is a rubber covered lateral inward extending cover plate 2G. The upper side of this plate 26 slidably contacts the rubber covered wall 21 of the plate chamber so as to produce a liquid seal therebetween.

The electrolyte containing the salt of the metal to be plated onto the strip is pumped or otherwise conducted from the storage tank I3 to the plating compartment I2 and enters through the conduit 28 passing through the perforations 29 of the anode 30 and on to the top side of the strip I as indicated by the arrows in Figure 3. In operation the electrolyte fills the space between the anode and strip. The anodes are preferably formed of a material which is insoluble in the electrolyte, for example carbon, lead or the like.

The anode 30 is formed of spaced apart central segments 3| and adjacent sections 32, as illustrated in Figure 7. The segments are connected by insulated studs 33 to the bus bars 34 y which are electrically in contact with the positive side of a generator or other source of electricity.

'I'he electrolyte entering on top of the strip near the center divides and flows uniformly'out- Ward to the edges of the sheet or strip and over into the trough 22 where it is returned to the storage tank through the pipe 35. The returned electrolyte is ltered, heated or cooled and replenished with the necessary chemical constituents while it is being recirculated from the troughs tothe inlets of the apparatus.

Wheels 36, 31 and 38 mounted on ball bearings make rolling electrical contact with the under side of the strip I and carry the current to the stationary brushes 39, which kslidably contact the wheels. The brushes are likewise connected to the bus bars 40 by means of the electric conducting members 40a. The bus bars are in tum electrically connected to the negative side of an electric generator or source of electricity toA complete theelectrical circuit. The wheels are spaced along thel shaft 4I and the outside wheel supports 42 and 43, together with the adjacent respective trough portion, are bolted together.

It will be understood that an adjustable trough will be provided adjacent the wheel support 43 similar to that shown at the left in Figure 3. The outside wheel supports 42 and 43 are thus attached to the angle members 44 and 45 and the brace arms 4E so as to afford a slidable arrangement of the parts on the shaft 4I. The shaft 4l is rotatably mounted in the support 48 through the aperture 43 in the upper part of the bracket I9. The shaft 4l is provided with right and left hand threaded portions 50 and 5I respectively which are in threaded engagement with the lugs 52 and 53 so that by turning the crank 5 the outer wheels and trough membersmay be adjusted for accommodating the apparatus to wider or narrower strip material for treatment. The supporting base member 55 for the trough engages the roller 5S during this movement.

The outer edge of the strip material is ailorded protection by the yielding rubber backing support 25against which the outer edges of the strip rest, as indicated at 5I. in the enlarged view Figure 12. The rubber covered trough 22 and plate 26 may be adjusted inwardly to shield the outer edge of the strip from being subjected to excessive amounts of current causing building up of the metal deposit at the edges.

After the strip has been plated on the top side it is withdrawn from compartment I2 and enters the plating chamber It which is similar to the plating compartment I2 except that the rolling contact wheels 36, 31 and 38 are arranged to vcontact the plated top side of the strip. The

outer edges of the strip are held against the rubber seal backing to provide a uid seal therebetween as at 58 and 58 illustrated in Figure 4. The electrolyte is in this case admitted upward and centrally against the bottom of the strip through the conduit 28 which in turn is connected to the electrolyte storage tank I5. In

this arrangement the crank 54 and threaded vshaft member 41 afford means for moving the wheels 3G and 38 slidably on the shaft 4I, carrying therewith the attached rubber covered trough plates 6I! so as to adjust the apparatus for receiving wide or narrow strips.

In this instance the electrolyte enters the compartment I4 between the segments of the anode 30 and upward against the central bottom surface of the strip. 'I'he electrolyte divides and ows outward to the edges of the strip and over into the rubber lined troughs 6I disposed at opposite sides of the strip edges, where it is returned to the storage tank through the pipe 62. The trough 6I is provided with slotted rubber walled partition 23a likewise as in trough 23, which aids in retarding the outflow of the electrolyte from the plating chamber I4 so that the chamber can be readily maintained full during operation.

The yielding rubber backing 63 provides sufllcient protection to the outer edges of the strip reducing the tendency to build up thicker coatings thereon than at the center of the sheet.

The supporting rolls 64 are used when necessary to hold the strip up while plating the under side as illustrated in Figures 8 and 9. The supporting rolls 66 are provided with graphite, rubber or other oilless bearings 65 which are de-V signed to operate under water. The bearings 65 are disposed in rubber covered U-shaped sockets 66, as illustrated in Figure 10.

The number of rolling contacts for each electroprocessing compartment will, of course, depend upon the size of the compartment, as indicated in Figure 5, and their spacing may be varied to accommodate the weight and size of the strip or sheet being treated. 'I'he contact brushes are provided with the conventional spring pressed bars il and wedge shaped electrical contact members I8 which engage the electrical conducting surlaces 69 of the wheels as illustrated in Figures and 6, providing a dry rolling electrical contact with the strip I.

'Ihe scrubbing section il consists of long, revolving brushes with a supporting roll to hold the strip against the brushes. The ilrst brush is on top and the second one below.

The burnishing section is similar to the scrubbing section but the brushes have fine wire bristles to bumish the soft plate, which in this case would be tin plate. Instead of burnishing rolls the plating may be followed byiluxing and heating or other methods of improving the physical characteristic of the deposit, according to the particular metal or alloy forming the plating coating.

It will be obvious that the details of this apparatus and the method oi' electroprocessing strips may be widely varied while preserving the principles of this invention, and it will be understood that such modifications as come within the scope of the claims are comprehended to be within this invention.

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

1. In a machine for electroprocessing long continuous flat strips oi' metal, a tank for holding treating solution, a trough elongated in the direction of the strip travel arranged adjacent said tank, said trough having laterally adjustable side wall portions for varying the sizel ot said trough to accommodate strips of different.

width, a series of rollers mounted on spaced axle members, said rollers and members being spaced along said trough in the direction oi' strip travel and arranged adjacent the open side of said trough for supporting and guiding said strip,

said strip forming a closure for the open side oi' said trough, means comprising liquid conduits interconnecting said tank and trough for conducting strip treating liquid into said trough from said tank, liquid distributing means forcing said treating solution to flow uniformly over and in contact with said strip as the strip material is moved along through said trough, and

means sealing the back side edges of said mov-v the open side of said trough for supporting and guiding the strip through said trough, said strip forming a closure for the open side of said trough, means for admitting strip treating solution under pressure centrally into said trough and in contact with said strip as it is moved along, and means sealing said moving strip along its marginal back side edges which are not in contact with the electrolyte to said trough.

3. In a machine for electroprocessing long continuous substantially ilat strips of metal of different Width, a tank for holding strip treating solution, a trough elongated in the direction of strip travel positioned adjacent said tants in communication therewith, said trough having laterally adjustable side wall portions, means for adjustably positioning said side wall portions to vary the size of said trough to accommodate different widths of strip, a series of rollers spacedly arranged adjacent the open side of said trough for supporting and guiding said strip along, said strip forming a closure for the open side oi' said trough, said spaced rollers including electrical contact means for conducting electric current through said strip as it is moved along through said trough, conduit means for circulating the strip treating solution from said tank into said trough and in contact with the strip as it is moved along, bale plate means arranged in said trough to distribute said treating solution evenly over said strip, means sealing said moving strip to said trough along the back side'of its outer edges which are not in contact with the electroiyte, and electrical conductor means for passing electric current through said electrolyte and said strip as it is moved along.

4. In a machine for electroprocessing long continuous substantially flat strips of metal, a tank for holding electrolyte, a trough arranged over said tank and elongated in the direction of the strip travel, said trough enclosing the side edges of said strip means sealing the back side edges of said strip which are not in contact with the electrolyte to said trough, a series of rollers arranged on spaced axle members, said members being spaced along said trough in the direction of strip travel and arranged adjacent the open side oi' said trough for supporting and guiding said continuous stripalong, liquid conduit means interconnecting said tank and trough for conducting electrolyte into said trough from said tank, and means comprising a perforated electrode plate arranged centrally and longitudinally oi' said trough i'or uniformly distributing said electrolyte over said strip, means for maintaining the outer side of said strip in direct electrical connection with a plurality of electric conductors, and means for conducting electric current through said electrolyte and to said strip while the strip is moved along through said trough,

'Iii

5. In a machine for electroplating long continuous substantially flat strips of metal, a tank for holding electrolyte, a trough arranged over said tank and elongated in the direction of the strip travel, said trough comprising adjustable sections for accommodating different size strips, a series of rollers mounted on spaced axle members, said axle members being spaced along said trough in the direction of strip travel and arranged adjacent the open side of said trough for supporting and guiding said continuous strip, liquid conduit means interconnecting said tank and trough for conducting electrolyte into said trough from said tank, a segmented electrode member arranged centrally and longitudinally of said trough for distributing the electrolyte over said strip as the strip is moved along through said trough, said strip forming a closure for the open side oi' said trough, means sealing the back side edges of said strip which are not in contact with the electrolyte to said trough, a plurality of spaced electric conductors for making electrical contact with the outer side of said strip material to conduct electric current through said electrolyte and said strip while the strip is being moved through said trough.

6. In a machine for electroplating long continuous substantially dat strips of metal, a tank fz'r Melding plating electrolyte, n trough amassed adjacent thereto and elongated in the direction of the strip travel, said trough comprising side wall and laterally extending portions forming a chamber for collecting electrolyte, means sealing each of the back side edges of said moving strip which are not in contact with the electrolyte to one of said laterally extending side wall portions at opposite sides of said trough so that the strip forms a closure for one side of said trough, fluid conduit means interconnecting said tank and trough for conducting plating electrolyte into said trough from said tank, a series of rollers mounted on spaced axle members, said members being spaced along said trough in the direction of strip travel and arranged adjacent the open side of said trough to support and guide said continuous strip as it is -moved along through said trough, a perforated anode plate arranged in said trough` and spaced from the moving strip, and means for passing electric" current to said anode plate and through said electrolyte to said 10v strip as it is movedtherealong.

WESLEY F. HALL.

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