US1509102A - Electrical conductor - Google Patents

Description

' Sept. 23 1924. 1,509,102

A. s. DANA ELECTRICAL CONDUCTOR Filed Jan. 26 1920 ELI 67770 Dims/7E0 [590 COVER/W6 mulflr/oly 5 -Zf6'77?/6 60/7500 77/76 W//?E INVENTOR m 4M 43%;

A TTOHNEY Patented Sept. 23, 1924.

UNITED STATES PATENT OFFICE.

,ALAN STANDISH DANA, OF SEYMOUR, CONNECTICUT, ASSIGNOR TO THE KERITE INSULATED WIRE AND CABLE COMPANY, A CORPORATION OF CONNECTICUT.

n ELECTRICAL CONDUCTOR.

Application filed January 26, 1920. Serial No. 354,089.

To all whom it may concern.

Be it known that I, ALAN STANDISH DANA, citizen of the United States, and resident of Seymour, in the county of New Haven andState of Connecticut, have invented certain new and useful Improvements in Electrical Conductors, of which the following is a specification.

My invention relates to electrical conductors and more particularly to electrical conducting wires with protecting coverings. My invention is particularly advantageous in the protection of insulated copper wires.

According to my invention I provide the electric conductor with a'coating or covering of a metal electro-deposited thereon,

' the physical characteristics of the metal coating being such that it remains coherent and substantially impervious under conditions of use and prevents any material diffusion of copper therethrough to the insulation. For many years it hasbeen understood that copper and the usual rubber insulation should not be placed in intimatecontact and it has been common to first cover the copper wire with tin. Tin has the advantage that it requires only a moderate heat to melt it so that it may be easily applied by dipping the copper wire into a molten bath of it. Also tin alloys readily with copper so that at the temperature of molten tin a firmly adherent coating is obtained. For many years, therefore, the tin coating has been substantially the only covering commercially employed for the purposes in question.

Conductors of this class are likely to be subject to hard usage and to all sorts of atmospheric andv climatic conditions.v In some cases acids or other chemicals are present either in liquid or gaseous form. While the intermediate tin coating has heretofore been commonly employed, it is found that under some conditions, after a greater or less lapse of time, the tin coating is destroyed, the inner surface of the insulation is deteriorated, the adhesion of the insulation to the conductor is lost and the surface of the copper is pitted. The immediate causes of this do not seem to be easily understood and therefore no remedy has been patent. It may be that the tin under certain conditions gradually becomes wholly alloyed with the copper causing a disappearance of the tin layer and subjecting the insulation to the deteriorating action of the alloy.

Probably in some cases electrolysis between the tin, copper and their alloys plays an important part. In some cases alternate wet and dry conditions seem to have something to do with it. The wide variation in the thickness of tin coating as well as in the thickness of the alloy may possibly accelerate action by electrolysis. In any event, I have discovered that by providing an adherent coating of a metal of certain characteristics,

these disadvantages may be largely if not entirely overcome. Also, according to my invention the coated conductor may be produced at relatively low cost.

According to my invention in its preferred form the conductor is substantially free of metal including alloy coatings which will form a material amount of alloy between the metal covering and the copper conducting wire, and which are materially more brittle than copper and which melt at a point near the melting point of copper, such would be the case if a compoundof (for example) .equal quantities of copper and Babbitt metal were placed on the wire by running the wire through a molten bath thereof.

According to a preferred form of my invention I provide a copper wire conductor having a thin continuous covering of lead of uniform thickness electro-deposited thereon, the lead being coherent and adherent to the copper and being substantially pure and of substantially the density and homogeneity of cast lead, whereby it remains substantially impervious with the bending and use of the conductor, and with a rubber-compound or other insulating covering containing rubber surrounding the lead covered wire adjacent thereto. The drawing is a perspective illustrating a portion of a conductor embodying my invention in one form. In the drawing 1 represents the copper or other electrical conducting wire, 2 the lead covering, and 3 the in- The thickness of the lead coatsulation. ing 2 isexaggerated on the drawing to more clearly illustrate the same.

In order that those skilled in the art ma more readily carry out my invention, I wi 1 now describe my preferred method of makmatters, adhering to the wire.

' formed by reason of any sulphuric acid in potashin a suitable tank. This solution I makeby dissolving'3l2 grams of dry stick caustic in a suitable amount of water and then diluting the same with water to one liter. If the tank be a large one several gallons of such a solution may be used. The wire preferably passes down vertically into the solution, and around a pulley at the bottom and then passes u-p vertically. here it comes outv of the solution I preferably pass it through a small glass tube to prevent dirt and the like on the surface of the solution from being drawn to and adhering to the wire as it isdrawn out of the solution- An' electric current is passed through the caustic solution from the wire as anode to the tank or other. suitable electrode as cathode. If necessary this bath maybe heated and agitated in any suitable manner. By thus treating the copper wire it is cleaned thoroughly. However, any other suitable means may be used for cleaning the wire, as pickling or sandblast. In some cases cleaningmay not be necessary.

From the caustic cleaning bath the sire is passed through a tank of running water in order to remove any caustic and other A: similar glass tube may also be used at the exitof the wire from the water and if desired similar glass tubes may be used at the entrance of the wire in both tanks.

From the tank of running water the wire passes through a lead fiuoborate electrolytic bath in a suitable tank. In this bath the wire is made the cathode and a lead. plate the anode. Such a bath may be prepared by taking 320 oz. of hydrofluoric acid and putting the same in a lead lined tank and slowly adding 140 oz. of boric acid. Afterthe solution has cooled,'190 oz. of basic lead carbonate are added with continuous stirring. The lead carbonate is added inthe form of a cream prepared by mixing it with a slight amount of water. The whole is then diluted to 10 gallons and filtered through a paper filter to remove any lead sulphate the hydrofluoric acid as an impurity. Before the electrolysis is commenced 100 grams of liquid glue or gelatin are added and stirred in. The voltage will vary with the shape of and distancebetween electrodes but is generally below one Volt and a current density of from to 260 ampere-s per square foot is preferred.

The lead is deposited on the copper wire as it moves continuously through the bath.

and I have found that not over 30 seconds is required between entering of the wire and itsexit from the bath in order to deposit thereon a satisfactory lead coating. From the elect-ro-deposition bath the wire passes through another tank of runnin water wherin the electrolyte is washed.- ti'om the wire and it is then preferably passed through aheated cylinder or subjected to a. blast of hot air to dry oil the water that may remain on the surface of the coated wire. The wire may then be reeled and later passed through any suitable type of apparatus which presses a rubber insulating compound of any suitable kind, around the wire to form an insulating coveringot uniform thickness. Or, from the drying operation the wire may pass continuously through straightening apparatus .of any suitable form and thence through polishing rolls and then through the apparatus for putting on the insulating covering, after which it is reeled. The wire may then be placed in to vulcanize the rubber in a manner well understood by those skilled in the art.

The coating or covering of lead which is applied to the copper wire by this preferred method is dense, coherent, continuous and adherent to the copper and of substantially tight iron cylinders and subjected to heat 1 uniform thickness and is substantially pure and of substantially the density and homogeneity of .cast lead and different from lead ods wherein the lead is left more or less porous, flaky and non-adherent so that it would coverings produced by various other methcoating adherent to the wire conductor. -By

the term wire I do not mean'to be limited to the ordinary wire I which is circular in cross section since in the broader aspects of the invention, the wire or. conductor may have any cross sectional shape-and may be made up of a plurality of elements forming a conductor of any cross sectional shape.

VV-hile my improvements are particularly advantageous in connection with rubber insulated conductor for the reasons above given, nevertheless the lead coating has certain advantages as a'protecting coating for wire conductors where no such insulation is used. Also according to the broader aspects of the invention the lead coating may beapplied in other ways so long. as it' is firmly adherent to the conducting wire and does not permit any substantial diffusion of the copper therethrough to the rubber insulation, and does not form a brittle coating.

VVherever I use the term -lead in the. claims appended hereto, I do not'mean to limit the claim or claims to pure lead or substantially purelead except where it is so defined in the claim or claims, since a substantial advantage is obtained even if the lead coating contains substantial quantities of some othermetals or impurities.

: lVhat I claim as new-and desire to secure wire and adjacent to said lead covering.

3. An electric conductor comprising a conducting wire having a coating of lead electro-deposited thereon, the lead being coherent and adherent to the conducting wire, and an insulating covering surrounding the lead covered wire.

4. An electric conductor comprising a copper wire having a thin coating of lead elec trodeposited thereon, the coating being of substantially uniform thickness and coherent and impervious and an insulating covering for said coated wire.

5. An electric conductor comprising a copper Wire, having a protective coating of lead thereon firmly adherent to the copper,

and an insulating covering containing rubher outside of the lead covered wire.

6. An electric conductor comprising a cop-- per conductlng wire having a covering of substantially pure lead around the same, and

an insulating covering containing rubber,

. ing rubber, outside of the lead covered wire,

the lead covering-on the wire being substan-' tially free of metal melting at a point near the melting point of copper and which alloys therewith.

. 8. An electric conductor comprising a copper conducting wire, having a: covering of lead around the same, and an insulating covering containing rubber, outside of the lead covered wire, the covering on the-Wire being substantially free of metal which is materially more brittle than the copper of the conducting wire. Y 9. An electric conductor comprising a copper wire with flexible insulating material surrounding the same, the insulating material being of a nature to be deteriorated if in contact with the copper, and a substantially pure-lead covering between the wire and insulation and firmly adherent to the wire, the lead covering being substantially free of metal which would form a material amount of alloy with the wire' and cause material deterioration of the insulation.

10. An electric conductor comprising a metallic wire with flexible insulating material surrounding the same, the wire and insulating material being of a nature to react with one another if in contact with one another, and a' non-brittle lead covering between the wire and the insulation preventing deterioration of the insulation by action from the metal of the wire.

11. An electric conductor comprising a copper wire with a flexible insulating material surounding the same, the insulating material containing rubber, and a lead coating on the wire between the wire and the insulation, and firmly adherent to the copper and substantially preventing reaction between the copper and the insulation.-

12. An electric conductor comprising a metallic wire with flexible ins'ulating material surrounding the same, the wire and insulating material being of a nature to react with one another if in contact with one another, and a coating of metallic lead electro deposited on the. wire underneath the insulation to prevent deterioration of the insulation by action of the metal from the wire.

Signed at New York in the county .of New of January A. D. 1920. v y i ALAN STANDISH DANA.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,509,102, 1924;, upon the application of Alan Standish Dana,

Electrical Conductors,

an improvement in granted September 23, of Seymour, Connecticut, for

fication requiring correction as follows: Page3, line 28, claim 4, after the word wire and before the period insert the words Said insulating covering containing rubber; same page, line 36, claim 6', strike out the words substantially pure and insert thesame before the word lead, line 31, claim 5; and that the said Letters Patent should be read with these corrections therein that the Same may conform to the record of the case in the Patent Signed and sealed this 4th day of November, A. D. 1924.

' [SEALJ- KARL FENNING, Acting Commissioner of Patents.

' York and State of New York this 23rd day I errors appear in the printed speci-

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