US2112691A - Electroplating anode unit - Google Patents

Description

March 29, 1938. w. A. CROWDER 2,112,691

ELECTROPLA'I'ING ANODE UNIT 7 Filed Jan. 30, 1956 s-sheets s'neet 1 ATTORNEY 5 March 29, 1938. w. A. CROWDER ELECTROPLATING ANODE UNIT Filed Jan. 30, 1936 3 Sheets-Sheet 3 INVENTOR.

ATTORNEYS Patented Mar.29,1938 2,112,691

UNITED STATES PATENT OFFICE ELECTROPLATING ANODE UNIT William A. Crowder. Newark, N. 3., assignor to Pyrene Manufacturing Company, Newark, N. J.,

a corporation of Delaware Application January so, 1936. Serial No. 61,455

7 Claims. (01. zoa-s) This invention relates to electroplating apparawhich one or more articles, generally indicated tus, one of its objects being to make possible the by the reference character A, may be suspended use of an inexpensive filter unit by which undeas cathodes and within which may also be sussirable constituents of the anode may be enpended a plurality of anode units U.

trapped so as to prevent their being dispersed The suspension means, for an article to be 5 generally throughout the electrolyte, and another plated, includes a suspension rod M to which an of its objects being to make possible the use of article to be plated may be suitably connected. a relatively small electrolyte tank with attendant T e Suspe s on Md 9 s or e at its upp e advantages such as conservation of space rewith a hook it, by which it may be suspended 10 quired for the apparatus as a whole and reducfrom arod-like support i5, mounted, for example, 10

tion in the quantity of electrolyte necessary to on a pair f win brackets 6 connected t enable the apparatus to function with efficiency. the side walls of the tank Ill. Preferably, therod To the above and other ends the invention i2 is square in cross-section so that it, at its contemplates a tank having a metal lining of hooked end, will bite more or less into the suplead and carrying an electrolyte within which the port 85 and thus insure an effective electrical 15 article or articles to be plated may be suspended connection between itself and such support. as cathodes and within which may also be sus- The suspension means for each of the anode pended a plurality of anodes from which the units U is substantially identical with the preplating material is derived, a slightly greater viously described article-suspenion means in that portion of each anode than-its immersed length it includes a suspension rod I'I formed at its upbeing surrounded by a non-corrosive and nonper end with a hook I 8 by which it may be susconductive tube-like guard which is so perforated pended from a odke pp 29, mounted, for as'to permit the passage of current from the example, on a pair of wing-like brackets 2! conanode only in a direction generally toward the heated to the side walls of the tank, the rod I1 article or articles to be plated and which for a. being preferably square in cross-section so that 25 portion of its submerged length is housed within it, at its hooked end, will bite more or less into v a non-conductive bag-like receptacle, of fibrous the support 20 and thus insure an effective elecmaterial, which is adapted, 0n the one hand, to trical connection between itself and such suppermit passage of the ions of the metal to be port.

deposited on the article or articles to be plated, Referring to the anode units U, it will be noted 3 and on the other hand, to obstruct and entrap that each of such units includes an anode 22 undesirable constituents of the anode, such as containing a plating material or materials as, for particles of graphitic carbon, so as to prevent example, iron and/or nickel, the anode being their being dispersed generally throughout the adapted for screw-thread connection at its upper electrolyte with deleterious results as they are end to its corresponding suspension rod l1, as 35 freed from the anode incident to thecarrying out shown most clearly in Fig. 1. of the plating process. Associated with and surrounding each of the Other objects and advantages of the invention anodes 22 is a non-corrosive and non-conductive will. become apparent from the following descriptube-like guard 24, preferably of hard rubber, tion, taken in connection with the accompanying which at its lower end extends a substantial dis- 40 drawings, in whichtance beyond the corresponding end of the anode Fig. l is a vertical, longitudinal, sectional view and which at its upper end protrudes a substan-. of an apparatus embodying the invention; Fig. 2 tial distance above the level of the electrolyte E. is a plan view of the apparatus; Fig. 3 is a frag- That portion of the tube wall nearest the article mental, transverse, sectional view taken on line or articles to be plated is rendered pervious, so 3-3 of Fig. 2; Fig. 4 is an enlarged fragmental, as to permit a flow of current through such wall sectionalview of an anode unit; Fig. 5 is a transin a direction generally toward the article or verse, sectional view taken on line 55 of Fig. 4, articles to be plated; and to that end the tube and Fig. 6 is a side view of an anode, drawn to may be provided with slots or holes, the latter scale with reference to Figs. 1 to 3 and correbeing employed in the present embodiment of the 50 sponding to the partially consumed anode illusinvention and hereinindicated by the numeral trated in Fig. 5. 25.. Where a tube-like guard 24 having, for ex- Referring to the drawings, the numeral III inample, an outside diameter of 1 is employed, dicates a suitable tank having a metal lining H, the holes 25 may each be, for example, 5 in diof lead, a carrying an electrolyte E wi hin ameter and spaced from each other ,6" asmeas- 55 ured from center to center. As illustrated in Fig. 4, the openings are distributed longitudinally of the guard throughout the major portion of its submerged length, but they, as illustrated in Fig. 5, are distributed arcuately of the guard over that portion of its peripheral area which is nearest the article or articles to be plated. While the arcuate extent of the perforations may be somewhat decreased according to conditions, it is believed that they, in keeping with their particular function to be hereinafter more fully described, should, in no event, exceed an arcuate distribution greater than the 180 distribution herein illustrated.

Enveloping each of the tube-like guards 24 throughout the major portion of its submerged length and entirely throughout the longitudinal extent of its perforated portion, is a non-conductive bag-like receptacle 26, of fibrous material, which is adapted, on the one hand, to permit passage of ions of the metal to be deposited on the article or articles to be plated, and, on the other hand, to obstruct and entrap'undesirable constituents of the anode 22, such as particles of graphitic arbon, so as to prevent their being dispersed generally through the electrolyte with deleterious results as they are freed from the anode incident to the carrying out of the plating process The bag-like receptacle 26 may be held in position on the guard 24 by the simple expedient of a rubber band or a draw-string 21, serving to constrict the upper or mouth-end of the receptacle into firm gripping engagement with the guard.

' In order that the several tube-like guards 24 i and their associated bag-like receptacles 26 may 'be' held in definite positions with relation to the.

together and securing them to each other by av plurality of rivets 32, or the like,'which pass transversely through both of such straps at points adjacent the several guards 24. The clamp 28 is supported as a unit by the simple expedient of a pair of hooks 34 connected to opposite ends of such clamp and suspended from the rod-like support 20.

From the foregoing it will be understood that when the anodes 22 and the article or articles A to be plated are connected, respectively, to the positive and negative terminals of a suitable source of electrical energy, not shown, a deposition of the plating material, for example, iron offered to the fiow' of current along such path is very I substantially less than the resistance peculiar to an imaginary path from any anode to the metal lining I I and thence from that lining to the article to be plated. Regarding the matter of diflerence in resistance, as just mentioned,

"it is to be observed from Fig. 2 that such dliler ence is accounted for by reason of the fact that the distances between any anode and the article or articles to be plated is substantially less than the shortest distance existing between an article to be plated and the met a1 lining II of the tank plus the shortest possible path existing between such lining and the'anodes as a group, the length of which path'is materially greater, due to the presence of the respective tube-like guards 24, than it would be in the absence of such guards, as will be readily appreciated when it is taken into account that the guards serve to block or prevent a flow of current from their respectively associated anodes except by way of the openings 25 which, in each instance, are formed in that portion of the-tube wall nearest the article or articles to be plated and in no event exceed an arcuate distribution greater than 180. Taking into account the fact that the length of the path from the anodes to the lining of the tank is substantially increased due to the presence of the guards 24, it becomes apparent that the walls of the tank may be located closer to the anodes than would be feasible in the absence of the guards and that the tank dimensions, especially the longitudinal dimension of the particular tank herein illustrated, may be kept at a minimum,

thus conserving space required for the apparatus as a whole and reducingthe quantity of electrolyte that would otherwise be necessary to enable .the apparatus to function with efficiency.

In view of the fact that the guards 24 insure against an undesirable flow of current indirectly to the article or articles to be plated by way of the metal lining I I of the tank, it is apparent that they are effective to not only insure against an uneven deposition on the article or articles to be plated, but also to obviate possible contamination of such deposit under the influence of electrolytic action that would be induced as between the metal lining itself and the article or articles to be plated.

Regarding the bag-like receptacles 26, the fact is here emphasized that they are so positioned on the tube-like guards 24 that they are wholly submerged within the electrolyte E at an appreciable distance below the surface thereof.v

Such disposition of the receptacles has been resorted to, because, in the development of the present invention, I discovered that even with an electrolyte only slightly acid in .its character receptacles of fibrous materials, such as canvas, could not be employed satisfactorily if they were so placed on theguards as to leave their upper ends exposed to the atmosphere above the level of the electrolyte, inasmuch as they would disintegrate al8ng a definite line not coincident with the electrolyte level but a slight distance above the same. 1 plained, generally speaking, by the fact that the liquid, which crept (because of capillarity) up that portion of the receptacle which protruded above the electrolyte level, was subjected to the action of atmosphere, it may be well to here note the observations made by me when depositing iron through the medium of an electrolyte containing ferrous sulphate as one of its ingredients While such disintegration may be exand when employing canvas receptacles so placed were formed, which, due to their highly corrosive nature, caused the receptacles to disintegrate after only a comparatively short period of time.

By the simple measure which I have resorted to, namely, so positioning the fabric receptacles on the respective guards that they are wholly submerged within the electrolyte at an appreciable distance below the surface thereof, I have overcome objectionable disintegration and .have thus obviated the necessity of relatively expensive filter pots; heretofore commonly employed.

Although only one form of the invention is herein shown and described, it will be understood that other changes may be made without departing from the spirit of the invention or the scope of the following claims.

What is claimed is:

1. In an electroplating apparatus containing an electrolyte, an anode unit including an anode partially submerged in the electrolyte, and a fibrous filter-receptacle enveloping the submerged portion of said anode only up to a point below the point to which the anode will be sub- 1 merged in the electrolyte.

2. In an electroplating apparatus, an anode unit including an anode, a non-corrosive and non-conductive guard surrounding said anode and extending upwardly beyond the point to which said anode will be submerged in the electrolyte, said guard having openings therein below the point to which said anode and said guard will be, submerged in the electrolyte, and a fibrous filter-receptacle covering said guard and the aforesaid openings therein up to apoint below the point to which said guard will be submerged in the electrolyte.

3. In an electroplating apparatus, an anode unit including an anode, a non-corrosive and non-conductive guard surrounding said anode and extending from beyond the bottom of said anode upwardly beyond the point to which the anode will be submerged in the electrolyte, said guard having openings therein below the point to which the anode and guard will be submerged in the electrolyte, and a fibrous filter-receptacle covering the bottom and perforated portion of said guard up to a point below the point to which said guard will be submerged in the electrolyte.

4. In an electroplating apparatus adapted to receive as cathodes the articles to be plated, an anode unit including an anode, a non-corrosive and non-conductive guard disposed in contiguous relation to the submerged length of said anode perforated wall portion on the side toward the article or articles to be plated.

6. In an electroplating apparatus adaptedto receive as cathodes the articles to be plated, an

' anode unit includingan anode, a non-corrosive and non-conductive guard disposed in a-contiguous relation to the submerged length of said anode, said guard having openings therein on the side toward the article or articles to be plated, and a fibrous filter-receptacle enveloping the perforated portion of said guard and extending up to a point below the point to which said guard will be submerged in the electrolyte.

7. In an electroplating apparatus adapted to receive as cathodes the articles to be plated, a tank having a metal lining and adapted to contain an electrolyte, an anode unit including an anode, a non-corrosive and non-conductive guard disposed in contiguous relation to the submerged length of said anode, said guard having openings therein on the side toward the article or articles to be plated and having an imperforate wall portion on the side away from the article or articles to be plated, and a fibrous filter-receptacle carried on and supported by said guard and enveloping only that portion of the guard which is below the point to which said guard will be submerged in the electrolyte.

WILLIAM A. CROWDER.

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