US1974441A

US1974441A - Process and apparatus for electroplating

Info

Publication number: US1974441A
Application number: US398490A
Authority: US
Inventors: Andersen Bjorn
Original assignee: Celluloid Corp
Current assignee: Celluloid Corp
Priority date: 1929-10-09
Filing date: 1929-10-09
Publication date: 1934-09-25
Anticipated expiration: 1951-09-25
Also published as: GB368727A

Description

Sept. 25, 1934. B. ANDERSEN PROCESS AND APPARATUS FOR ELECTROPLATING 4 Sheets-Sheet 1 INVENTOR WAN BY RNEY Filed Oct. 9, 1929 Sept, 25, 1934. B. ANDERSEN PROCESS AND APPARATUS FOR ELECTROPLATING Filed Oct. 9, 1929 4 Sheets-Sheet 2 Q RNEY INVENTOR BY I Sept. 25, 1934. B. ANDERSEN PROCESS AND APPARATUS FOR ELECTROPLATING Filed-Oct. 9, 1929 4 Sheets-Sheet 3 INVENTOR W BY %@L Sept. 25, 1934. B. ANDERSEN 1,974,441

PROCESS AND APPARATUS FOR ELEGTROPLATING Filed Oct. 9, 1929 4 Sheets-Sheet 4 will IINVENTOR mm i HQEQRQIEY Patented Sept. 25, 1934 PROCESS AND APPARATUS FOR ELEC'I'BOPLATING Bjorn Andersen, Newark, N. 1., assignor to Celluloid Corporation, a corporation of New Jersey Application October 9, 1929, steam. 398,490

10 Claims.

This invention pertains to the general class of electroplating and particularly to a process and apparatus for the. intermittent building up of a homogeneous, continuous, endless surface by electrodeposition.

As is well known, certain metals, particularly those less noble than hydrogen, after being deposited by electrolytic means, will not. after a relatively short pause in plating, permit a further building up of the surface already deposited to form a homogeneous mass. A more or less clearly defined'dividing surface appears between successive deposits. Strata are thus formed; or in other words the deposits are not thoroughly l6 united one to the other. The strata can generally be separated by mechanical means, and when the electroplated part is put to certain uses the strata exhibit a marked tendency to peel from each other.

The cause of the formation of these dividing surfs ces between successive deposits is not known, and I offer the following as a probable explanation. I

It is thought that the metal, (of which nickel is an example), during the electroplating operation, has hydrogen atoms incorporated in its surface, thus forming a hydrogen alloy of the particular metal. The presence of the hydrogen atoms permits the formation of a homogeneous layer of electrolytically deposited metal, particularly when the hydrogen overvoltage of the metal surface and the cathode potential are raised to such values as to permit metal deposition at a low rate of hydrogen ion discharge. When the deposited metal is removed from the bath of electrolyte, and the current is interrupted for a certain length of time, it is thought that the hydrogen atoms form into hydrogen molecules, which, perhaps, have a lesser affinity 4.0 for the metal, and therefore eventually escape therefrom. After the hydrogen has escaped from the metal, it then becomes impossible to continue plating without the formation of dividing surfaces between successive layers, since the hydrogen alloy surface must again be built up before the polarization will permit a high rate of metal deposition with a simultaneous low rate of hydrogen ion discharge. In other words, the

deposited metal after standing out of the bath for a sufficient length of time to lose its potential must again be activated before normal deposition occurs. The dividing surfaces are. formed during the re-activating operation and can be clearly seen under the microscope. The problem of producing a smooth, even, continuous, relatively heavy and homogeneous electroplated surface is of particular importance in film casting apparatus. Apparatus of this character is shown in the patent to John H. Stevens and Marshall C. 50 Lefferts, Serial No. 573,928, December 29, 1896. The belt and the wheel must both have a high polished, smooth, even surface in order that the dry or partially dry film of cellulosic plastic dope may be stripped therefrom, and have a highly polished surface free from lines, blemishes or imperfections of any character. The film thus made is generally cut into narrow strips and used for moving picture purposes. The importance 'of a surface without imperfections is therefore 0 readily apparent. To obtain such a surface the belts or wheels have generally been plated with nickel.

A great deal of difllculty is experienced in plating both the belts and the wheels. The belts generally range from about 20 to 60 inches in width and from about 45 to 125 feet in length. In order to plate a belt heretofore, it has been necessary to pass same through an electrolytic bath before the ends of the belt are joined. The 89 belts are of such size and weight, that heretofore it has been impossible to plate same except while in strip form, inasmuch as it is impractical to submerge the whole belt at one time. No matter what character of joint is formed in bringing the ends of the plated belt together, it is impossible as a practical matter, to entirely remove traces of the joint, such that same will not be reproduced in the film cast upon the belt,

The plating of belts and wheels of this character is very expensive, consumes considerable time and involves a great deal of labor. It is, therefore, highly desirable to deposit a relatively heavy coating of metal on the surface of the belt or wheel in order to prolong its life as much as possible, and thus increase the interval between electroplating operations.

It is, of course, obvious that belts and wheels of this size cannot as a practical matter be entirely submerged in the electrolyte. It, therefore, becomes necessary to pass portions of the belts or wheels through the electrolyte, and although the movement of the surface through the electrolyte may in some instances be hardly perceptible, it is generally impossible to deposit the required thickness of physically satisfactory metal during one insertion in the electrolyte. The final coating is, therefore in many instances depending upon the metal used, made up of a plurality of successive deposits. As heretofore pointed out,

in the case of certain metals, it has heretofore been impossible to eliminate the dividing surfaces between successive deposits.

Film casting apparatus is subjected to severe usage, and the peeling of portions of the outermost layer causes considerable losses due to shut downs and rejected material.

' Certain of the ingredients used in film casting dope, in some instances, are corrosive in character. Nickel, for instance, as well as other metals, is not entirely impervious to certain of such corrosive substances, with the'result that corrosive action is set up between successive deposits. This corrosion, of course, loosens the deposlts'from each other and greatly increases the tendency of the outer-most layer to peel.

An object of this invention therefore is to provide means whereby a homogeneous coating of electrolytically deposited material may be obtained.

A further object of this invention is to provide means whereby successive layers of electrolytically deposited material may be joined into a single, homogeneous, final coat.

A further object of this invention is to provide means for obtaining an electrotlytically deposited coating having uniform wearing qualities.

A further object of this invention is to provide means whereby successive layers of electrolytically deposited material will be permanently joined to each other.

A further object of this invention is to prevent corrosive action between successive electrolytically deposited layers.

A further object of this invention is to provide a continuous, endless layer or coating of electrolytically deposited material.

A further object of this invention is to provide a smooth, highly polished, layer or coating of electrolytically deposited material.

A further object of this invention is to provide means for electroplating an endless belt or other endless surface.

A further object of this invention is to provide means for plating an endless belt or other endless surface with a plurality of layers of material.

A further object of this .invention is to provide means for electroplating an endless belt or other endless surface with successive layers of homo geneously united electrolytically deposited material.

A further object of this invention is to provide novel apparatus for electroplating an endless beltor other endless surface.

A further object of this invention is to provide novel means for producing a smooth final surface.

Further objects and advantages will appear to persons skilled in the art as the specification proceeds.

My novel method and apparatus incorporates means for applying electrolyte to that portion of the cathode which may be at any time out of the electroplating tank. I also regulate the interval between successive submersions of each portion of the cathode in the solution in the electroplating tank. By employing either or both of these expedients, prior deposits are maintained in an activated condition. The metal already deposited is thus kept in a condition such as to permit further deposits without leaving a surface of demarcation.

The cathode travels continuously in and out of the main body of the electrolyte, and during the interval that any portion is out of the electrolyte, said portion may be covered with a spray or film of electrolyte which may be made to flow in a continuous stream back into the main body of electrolyte, thus maintaining electrical contact therewith. The entire cathode is thus virtually submerged in electrolyte at all times.

In the drawings wherein like characters represent like parts in the various figures,

Figure 1 is an elevation of apparatus adapted for electroplating the surface of an endless belt. Figure 2 is a section on line 2-2 of Figure 1. Figure 3 is a section on line 3-3 of Figure 2.

Figure 4 is a plan view of a reciprocating brush showing parts broken. I

Figure 5 is a plan view showing a cylindrical cleaning brush showing parts broken.

Figure 6 is an elevational view partly in sec tion of a modification of the invention.

Figure 7 is an elevation partly in section of a further modification of the invention.

For the purposes of illustrating the invention, I have shown in the drawings, apparatus capable of electroplating an endless belt. It is of course understood, that the invention is not limited to the apparatus shown, nor in general to any particular type of apparatus.

Referring to Figures 1, 2 and 3, at 1 is shown a tank which may be of any suitable material and construction. Partly submerged in the tank 1 and spaced from each other are wheels or

pulleys

2 and 3 mounted on shafts 4 and 5. The shafts 4 and 5 are journaled in suitable bearings mounted on the side of the tank 1. The bearings 6 and '7 for shaft 5 are shown in Figure 2.

Directly above tank 1, and preferably equally spaced from pulleys or

wheels

2 and 3 is pulley or wheel 8, having a shaft 9 iournaled in suitable bearings such as 10, mounted on any suitable support such as illustrated at 11. The support 11 should be so constructed as to be adjustable to and from the pulleys or

wheels

2 and 3, or in other words from the stationary support 12, in order to vary the tension and take-up slack in the belt 13 mounted on pulleys or

wheels

2, 3 and 8. Belt 13 comprises the cathode.

The belt or cathode 13 is endless. For film casting purposes this belt 13 is generally either of steel or copper, and is generally made in one continuous length of proper width. The ends are then brought together and united by any suitable means such as welding or brazing or otherwise. The joint is then polished so as to form a smooth surface. The belt. of course, may be formed by any other means.

In the tank 1, directly above the belt 13 and between pulleys or

wheels

2 and 3 is preferably placed a belt guide 14. The belt guide 14 comprises a base member 15 which is flat and slightly wider than the belt 13. The base member 15 is preferably of such length as to allow free rota.- tion of the

pulleys

2 and 3. On opposite sides of the base member 15 and projecting below the lower surface thereof, are strips 16 and 17, having

guards

18 and 19 respectively attached thereto.

The

guards

18 and 19 are angular in cross section I and each has a flange which projects inward slightly from the side edge and over the lower face of the belt. These flanges are spaced sufliciently below the lower surface of the belt to permit free movement thereof.

Guards

18 and 19 are provided with a plurality n mounted on U shaped supportingmembers 22, having overturned ends 25 adapted to slide in channels 26 in brackets 27 attached to opposite sides of the tank 1. The brush supporting members 22 are connected together by

lower strips

28 and 29 and by

upper strips

30 and 31. Opposite ends of each of the

strips

30 and 31 have off-set portions 32 which correspond tosimilar off-set portions 33 on braces 34, attached to the ends of

strips

30 and 31. Each ofi-set portion 32 cooperates with an off-set portion 33 to form a fork which fits over a sleeve 35. A sleeve 35 is fitted over and secured to opposite ends of each of shafts 4 and 5 and between the bearings thereof. Each sleeve 35 has a closed channel 36 somewhat in the form of the figure 8, but extending around the sleeve as well as transversely thereof. A. pin 37 passing through the off-set portion 33, fits into said channel 36 in the sleeve 35. It is obvious that rotation of the shafts 4 and 5 rotates sleeves 35, causing the forks formed by the off-set portions 32' and33, to reciprocate longitudinallyof the sleeves 35. This reciprocatory motion is transmitted to the

strips

30 and 31 and from the strips to the U shaped brush supporting members 22 attached thereto. The brushes 21 are thus caused to brush the lower surface of the belt 13.

' The channels 26 in brackets 27 which receive the ofi-set portions 25 of the brush supporting members 22, hold the brushsupporting members 22 in position.

Adjacent pulley or wheel 3 and journaled in V suitable bearings (not shown) on opposite sides of the tank 1 is a cylindrical brush 38, positioned transversely of and in contact with the belt 13.

Motion is transmitted to the shafts 4 and 5 and brush 38 by means of a longitudinal shaft 39 belted to a motor 40. Shaft 39 is connected to the shafts 4, 5 and brush 38 by means of suitable spiral gears 41. Shaft 39 is journalcd in bearings 42 attached to the tank 1.

Adjacent opposite ends of each of the pulleys or

wheels

2 and 3, are upwardly extending braces 43 attached to opposite sides of the tank 1. The upper ends of the braces 43 turn inwardly as shown at 44 and are attached to opposite ends of a brush support 45. Suitable insulation 46 insulates the ends 44 from the brush support 45. Brushes 146 may be of any suitable shape and are so positioned as to be held in contact with the inside surface of the belt 13. Any suitable arrangement may be provided for making adjustments for W631.

In the bottom of tank 1 extending transversely thereof are suitable anode supports 47 which may be provided with notches 48 aligned in a manner so as to receive anode rods 49. A busbar 50 connects the anode rods 49 and a lead 51 carries the connection to the top of the tank 1.

The electrolyte in tank 1 is preferably maintained to a height corresponding to the dotted line 52. For this purpose an overflow pipe 53 connected to a reservoir 54 is provided. Reservoir 54 is connected to a pump 55 by means of pipe 56 having a valve 5'7. Tank 1 is connected directly to the pump 55 by means of a pipe 58 having a valve 59. Pipes 56 and 58 lead into a filter 66 which is connected to the pump 55 by means of a pipe 61. The outlet of pump 55 is connected to pipe 62 which branches at 63 into branches 64 and 66. Branch 64 has a valve 65 and empties into the tank 1. Branch 66 having a valve 67 leads to a point above the pulley or roller 8 and through a suitable spray or sprinkler arrangement 68, discharges'onto the belt 13. The

discharge from the spray or sprinkler 68 flows downwardly over belt 13 in both directions and thus keeps that portion of belt 13 which is at anytime outside of the tank 1 covered with'a film of electrolyte.

Pipe 64 discharges into tank 1 in the rear of a foam and sediment trap composed of bailies 70 and 'I1 vertically arranged and having their lower edge spaced from the bottom of the tank 1, and bames 72 and '13 alternating with

baflies

70 and 71, having their lower edges in contact with the bottom of the tank and their upper edges spaced from the top thereof.

Bailles '74 and 75 at the outlet end of the tank are similarly arranged and provide a foam and sediment trap for the outlet from which leads pipe 58. "Pipe 53, which is an overflow and which empties into the reservoir 54 is intended amon other things, to draw of! foam and floating foreign substances, as well as maintain a constant level.

In Figure 5 is shown a detail of the brush 38. The tufts of bristles or similar devices in the brush 38 are not arranged in a plurality of parallel planes spaced longitudinally of the brush as is common practice in brushes of this type. On the other hand the tufts of bristles are arranged on the line of a single or multiple thread or helix extending from one end to the other of v the cylindrical base. If-a single thread is emtles or similar devices. In the case of a multiple thread, the pitch is preferably substantially equal to the number of threads times the diameter of the tufts of bristles or other devices. Other pitches, however, may be employed. This construction is preferred in order to prevent a series of parallel lines on the belt 13, which would be caused if a cylindrical brush of the ordinary type were used. These lines are apt to be caused by the divisions between the bristles. In the brush shown in Figure 5 each tuft 76 is offset circumferentially with respect to each adjacent tuft yet overlaps same. Thus any line formed by an edge of one tuft is immediately wiped out by the next succeeding tuft. It is thus possible to keep the belt 13 highly polished at all times, thus building up a coating having an unusually smooth homogeneous surface.

This overlapping relationship may be carried out in the reciprocating brush 21 if desired.

- However in view of the plurality of longitudinal rows of bristles, the tendency to produce lines is greatly diminished.

It is of course, understood that the belt 13 may be of any length or width and that the deposit maybe of any thickness within practical limits.

In operation the belt 13 is mounted on pulleys or

wheels

2, 3 and 8 by any suitable means. It is of course, understood that the belt 13 in many instances is very cumbersome and heavy. In some instances it may be desirable to remove everything from thetank 1 including the pulleys or

wheels

2 and 3. After the belt 13 is passed over the pulley or wheel 8, one of the pulleys or

wheels

2 or 3 may be remounted in its bearings and the belt then brought to place by mounting the other wheel or pulley in its bearings. Slack in the belt 13 may then be taken up by means of raising the adjustable support 11. If the anode bars 49, or both the anode bars 49 and the supports 47 have been removed, they may now be replaced. Brush supports 22 may then he of the tank. Belt guide 14 which may be mounted on supports 77 extending transversely of the tank 1 may then be placed in position, it being understood that any or all of the strips 16 and 17 andguards 18 and 19 may be made removable for this purpose. Brush supports 22 may then be brought up into place and connected with the mechanism for operating same. It is of course understood, that the brackets 27 may be made removable for this purpose. With all of the parts in place, the belt is given a final'cleaning and the tank is filled with electrolyte preferably up to the line 52. Brush supports 45 are brought into position such that brushes 146 contact the rear or inside face of the belt 123. Brush 38 may then be brought into contact with the outside face of the belt 13.

The apparatus is now ready for plating. The positive terminal of a source of electrical energy, (not shown), is connected to the lead 51 and the negative terminal is connected to the brush supports 45.

Motor 40 is brought into operation together with the pump 55. The flow of electrolyte to tank 1 is preferablycounter to the movement of the belt 13. The electrical circuit may now be closed. Anode bars 49 may be replaced from time to time as found necessary and convenient.

Guards

18 and 19 lengthen the distance to the edge of the belt 18 from the anode 49 and thus prevent treeing about the edges of the belt 13. Reciprocating brushes 21 remove gases and other foreign matter from the surface of the belt 13. Brush 38 may revolve in either direction and not only removes foreign matter from the surface of the belt, but keeps same highly polished. For this purpose brush 38 may be separately driven by a reversible motor or similar arrangement. Each successive deposit of metal on the belt is thus polished with the result that the final coat is without high spots and is perfectly smooth.

The speed of the belt 13 will depend somewhat upon its length. The lowest practicable speed for belt 13 will depend somewhat upon climatic conditions, condition of the metal and electrolyte as well as the volume of the spray issued by the member 68. I prefer merely as a practical guide to maintain no portion of the belt out of the solution in the tank 1 for a longer period than one minute. If the member 68 is eliminated the speed of the belt of course, should preferably be correspondingly greater. The amount of liquid that issues from the member 68 may be regulated by the valves 65 and 67.

I prefer to draw off the electrolyte from tank 1 through pipe 58 into filter 60 and then into pump 55, keeping the valve 57 wholly or partially closed. This allows any excess of electrolyte to settle into the reservoir 54 through pipe 53. Foam is also drawn off through pipe 53. By opening the valve 5'7 occasionally, or keeping same partially open, the excess of electrolyte pumped into the tank 1, slightly raises the level thereof so that foam and floating foreign matter are washed through pipe 53 into the reservoir 54.

The belt guide 14 will ordinarily prevent any substantial deposits on the inner surface of the belt 13. If desired, however, the rear of the belt, may be coated with a varnish or lacquer or other substance capable of resisting electroplating and mechanical action. The brushes 146 may then be brought into contact with the edges of the belt 13 instead of the inside surface.

In the event that the entire belt is to be plated, the base 15 of belt guide 14 may be made reticular in form and may if desired, be used to support additional anodes.

Guards

18 and 19 may be entirely eliminated or same may be U shaped to slightly enclose-the edges of the belt 13.\ Reciprocating brushes corresponding to the brushes 21 can be added if desired, by positioning same in transverse channels through the base 15. Such reciprocating brushes can be operated by the same mechanism that operates brush supports 22. A brush similar to brush 38 can also be added to polish the inside face of the belt if desired.

Any desired thickness of material may thus be deposited'on either or both faces of belt 13, as well as the edges thereof. The various layers may be united without dividing surfaces. However, it is understood that a superior bond may be effected even with a dividing surface without departing from the spirit of the invention. In other words, the invention is not limited to the elimination of dividing surfaces but includes all intermittent plating wherein a superior bond between successive layers is produced by this means. For film-casting apparatus, belt 13 is generally either of steel or copper. If the belt is of copper, nickel may be deposited directly thereon. If the 'belt is of steel, it may be copper-plated or given a light coat of nickel prior to copper and then nickel again. It may also be given one heavy coat of nickel only. The copper plating may, of course, be done by the same means. Any other order of coats as well as metals may of course, be employed.

It is understood, that the invention is not limited to those metals which are inclined to form surfaces between successive deposits inasmuch as the method and apparatus disclosed are applicable to the surfacing of an endless belt or other surface without regard to the material deposited or the formation or elimination of dividing surfaces.

Pulleys or

wheels

2, 3 and 8 are preferably flanged as shown and may be provided with a series of parallel circumferential flutes 238 as shown, if desired. These pulleys or wheels may also be surfaced with some electrolytically inert material such as a cellulosic plastic, bakelite, hard rubber, etc.

Referring now to Figure 6 wherein a modification is shown, tank is formed with a bottom 81 having

portions

82 and 83 sloping upwardly. Anode supports 84, support anodes 85 and hold the anodes 85 more or less parallel to the belt 86. Belt 86 is mounted on four wheels or

pulleys

87, 88, 89 and 90. The wheel or pulley 88 is larger in diameter than the others, thus giving the belt 86 an upward slope in the tank 80 from the wheel or pulley 88 to either of the wheels or pulleys 87 and 89. This construction permits gases that may collect on the under surface of the belt 86 in the tank 80 to flow upwardly along the lower surface of the belt 86 and escape at the wheels or pulleys 87 and 89. The operation of the modification is otherwise similar.

Referring now to Figure 7 wherein a further modification is shown, wheels or pulleys and 101 support belt 102. Wheel or pulley 100 is of a much larger diameter than the wheel or pulley 101. In the case of long belts the wheel or pulley 100 may be as much as from ten to fifteen feet in diameter or more. The lower portion of wheel or pulley 100 is submerged in tank 103 having anodes 104 therein, together with

foam traps

105 and 106. In this particular instance circulation of the electrolyte may be accomplished by drawing off electrolyte from the bottom of tank 103 through the filter 107 by means of pump 108 which empties into a reservoir 109. Reservoir 109 discharges into tank 103 through pipes 110 and 111. Electrolyte is carried to the top of the belt 102 through a pipe112.

In this modification gases are permitted to escape readily around the lower curved surface of the belt 102. This type of apparatus may be preferred for plating shorter belts.

While I have described the belts as being without joints, it is to be understood that jointed belts may also be plated. The joints may be entirely covered with the deposited metal and a smooth surface result, or a space may be left 'or other means as a coating employed to prevent the metal from building up from one end to the other.

Although the invention has been described in connection with belts it is understood that it is also applicable to film casting wheels as well as many other'articles without limit. The apparatus shown in Figure 7 for instance can be modified for wheel plating purposes by removing the pulleys or

wheels

100 and 101 and substituting the wheel to be coated for the wheel or pulley 100. Pipe 112 may then be brought down to discharge on top of the wheel-to be coated. Revolving' brush 38 as well as the reciprocating brushes 114 may then be brought into contact with the surface of the wheel.

To prevent any possibility of contamination of the electrolyte or the surface of the cathode, I prefer to encase the entire apparatus after the cathode is in place.

It is of course understood that a belt may be mounted on 'a single wheel such as the wheel 100, and plated in this manner. Blocks, chims, an expanding-contracting rim or other means may be employed to hold the belt to the wheel.

Should a belt composed wholly of deposited metal be desired it is merely necessary to coat the cathode with a material which would permit deposition of the metal and yet prevent the deposit from uniting to the cathode. Wax, electrotypers graphite and similar substances may be used for this purpose. After a belt of the desired thickness is obtained, it is stripped from the cathode. Such a belt is far superior to other belts of this type inasmuch as it is without joints, and therefore highly desirable for many applications, particularly film casting'apparatus.

If the supporting wheels of the electroplating apparatus are of the same diameter as the supporting wheels for the belts when in use, any tendency for the layers to separate due to unequal stresses is greatly minimized, inasmuch as successive deposits have been made to adjust themselves to wheels of similar diameter while being built up.

It is of course understood, that the detailed description of apparatus herein set forth is merely by way of illustration, and that this invention is not limited to any particular construction, nor type of apparatus, nor to specific parts thereof.

Having disclosed my invention it is obvious that many modifications may be made in the same within the scope of the claims without departing from the spirit of the invention.

I claim:

1. Process of electroplating which comprises intermittently submerging an object in an electrolytic bath and plating said object while submerged, there being a substantial interval between successive immersions, and maintaining the unsubmerged portion of the object wetted with electrolyte betwen the platings.

2. Process of electroplating which comprises re-, peatedly passing successive portions of an object in and out of an electrolytic bath and. plating said portions while in said bath, there being a substantial interval between successive immersions in the bath of any. particular portion of said object, and maintaining the portions without the bath wetted with electrolyte between the platings.

3. Process of electroplating which comprises repeatedly passing successive portions of an object in and out of an electrolyticbath and plating said portions while in said bath, there being a substantial interval betwen successive immersions in the bath of any particluar portion of said object, and maintaining the portions without the bath wetted with electrolyte between the platings, the said wetted portions being returned to the bath before said portions have lost the eflects of prior plating. 1

4. Process of electroplating which comprises intermittently and repeatedly submerging portions of an object in an electrolytic bath and plating said objectawhile submerged, there being a substantial interval between successive immersions, and subjecting the unsubmerged portions of said object to a spray of electrolyte between the platings.

5. Process of electroplating which comprises repeatedly passing successive portions of an ob,- ject in and out of an electrolytic bath and plating said portions while in said bath, there being a' substantialinterval betwen successive immersions in the bath of any particular portion of said n object, and subjecting the unsubmerged portions of said object toa spray of electrolyte between the platings.

6. Process of electroplating which comprises repeatedly passing successive portions of an object 115 in and out of an electrolytic bath and plating said portions while in said bath, there being a substantial interval between successive immersions in the bath of any particular portion of said object, and subjecting the unsubmerged portions of said ob- 12o ject to a spray of electrolyte between the platings, the said plated portions being returned to the bath before losing the efiects of prior plat- 7. Process of electroplating which comprises repeatedly passing successive portions of an object in and out of an electrolytic bath and plating said portions while submerged, there being a substantial interval between successive immersions in the bath of any particular portion of said object, spraying the portions out of the bath with elec- 13o trolyte between platings and returning said p'ortions to said bath before losing the efiects of prior plating.

8. Process of electroplating nickel upon a metallic object of large dimension which comprises intermittently submerging portions of said object in an electrolytic bath containing nickel and plating said portions while submerged, there being a substantial interval between successive immersions in the bath of any particular portion of the object, and maintaining the portions out of the bath wetted wih electrolyte beween the platings.

9. Process of electroplating which comprises repeatedly passing successive portions of a large metallic object in and out of an electrolytic bath containing nickel and plating said portions of the object while in the bath, there being a substantial interval between successive immersions in the bath of any particular portion of said object, and h sive immersions in the bath of; any particular portion of the belt, and maintaining the portions of the belt out of the bath wetted with electrolyte between platings. n

BJORN ANDERSEN.

there being a substantial interval betweensucces-