US2125836A - Conductor covering, method and compound for treatment thereof - Google Patents

Description

Aug. 2, 1938. J. w. oLsoN CONDUCTOR COVERING, METHOD AND COMPOUND FOR TREATMENT THEREOF Filed June 19, 1935 lNvENToR. c/BH/v WOL .so/v

lONUOQOU ATTORNEY.

iatented Aug. Z, 1938 UNiTD STATES ONDUCTOR COVERING, METHOD ANB COMPOUND FOR TREATMENT THEREOF Joili W. Olson, Dobbs Ferry, N. Y., assigner to Anaconda Wire e Cable Company, New York, N. Y., a. corporation ci Delaware Application June 19,

l 1i claims.

This invention relates to an improved conductor covering as well as the method and compound for improving the conductor. The chief feature relates to the inclusion of graphite in the jacket enclosing the conductor. The graphite can be applied by incorporating it in either the saturant y cambric with a iibfrous jacket, such as a cotton braid, jute, or sisal braid and to saturate such. jacket by passing the jacketed conductor through al bath of compound usually of an asphaltic base. This bath has been either a ame retardant or non-flame retardant material. And it is old in the art to use saturants of wax, stearin pitch, petroleum base asphalts or natural base asphalts.

in wire or cable adapted to be pulled through ducts or' conduits, it has heretofore been the practice to coat the saturated iibrous jacket with wax to increase the ease of pulling the same. When such wire has been made iiame retardant, stearin pitch has been applied over the saturated iibrous covering and then a thin coating of wax-like cornpound applied over the stearin pitch. The waxes used have been low in` melting point and frequently melted or iiowed if the cables were operated at the maximum temperature permitted by the insulated covering. Very high melting point waxes which would meet the service conditions and which would still provide the lubricating coating on the saturated fibrous covering are very costly and for this reason have not been applied to any large extent. Where a thin wax coating has been used over stearin pitch, in practice, the coating frequently rubs ofi when passed over a projection or turn in the conduit or duct, this results in exposure of the adherent or tackystearin pitch and interferes materially with the pulling of the conductor into a duct. Conductor jackets treated with conventional impregnating compounds, when bent on a small radius, are open to the objection that such bending has a tendency to cause disin tegraticn of the compound with a consequent les'sening of its intended protective function.

The single gure in the accompanying drawing is an elevation with parts broken away, illustrating an embodiment of the invention. The legends in the drawing are to be interpreted in an illustrative rather than a limiting sense. g v

My invention aims to overcome these diiiiculties 1935, Serial No. 27,372

and to provide an improved product as Well as a method for treating the same and a compound for saturating the jacket. in the" improved conductor covering, the graphite incorporated will perl mit the same to be readily pulled into conduits or 5 ducts Without sticking or dragging. The characteristics of the improved conductor covering are such as to permit o higher operating temperatures in service without injurious effect on the conductor covering. The improved covering can 10 be embodied in a flame retarding or non-flame retarding jacket depending upon the constituents of the satur'ant or finishing material used.

The invention avoids the use of the old low melting point waxes and contemplates the use of l5 graphite lled saturants or'lnishers to overcome the diihculty of sticking of coils or reels, or the diiculty of pulling the covered wires or-cables into ducts or conduits.

The wax-like substances used heretofore have 20 been paramn and the like, which have a relatively low melting point and are subject to migration and sticking of the cable in the conduit or ducts.

In treating conductor coverings,according to my improved method, if desired, I may incorporate either Hake or `amorphous graphite in a saturant of bituminous or asphaltic material and pass the conductor with its enclosing fibrous jacket through this material. Or, I may iirst pass the jacketed conductor through a suitable satu- A rant'and then apply the graphite by passing the conductor through a container containing graphite so that the same will adhere to the. saturated jacket, whereupon the asaturated and graphite 35 coated conductor can be passed through a die such asis commonly employed in the art.

The thus treated conductor covering may then be subjected to a nishing treatment by passage through a bath consisting of` a compound of bituminous material, asphaltic material and wax such as Montann wax, this bath also containing a substantial quantity of graphite.

Alternatively, thek jacketed conductor may be subjected to a conventional saturating treatment 45 in asphaltic or bituminous materials and tlrien subjected to a finishing treatment by passage through a bath carrying a substantial percentage of graphite. Regardless of whether the graphite treatment of the jacket is accomplished during the saturating or nishing step, I deem it important toapply a suiiicient percentage of graphite so that in the iinished product the coating will be rendered non-sticky and endow the coated conductor with self-lubricating characteristics.

A suitable compound may be made up as follows:

Per cent Stearin pitch 35 Montan wax 15 Asphaltic material such as gilsonite 10 Graphite either amorphous or flake e 40 In some cases, I nd that good results can secured by employing a smaller percentage of graphite, in which case I add carbon black and slate dust. Thus, an alternative compound, approximately as iollows may be used:

. Per cent Btearin pitch approximately 30 Montan wax approximately 18 Asphaltic material such as gilsonite 12 Flake graphite 15 Carbon black 10 Slate dust 15 'me compound described is usually maintained with a mixture of paraiiln and Montan wax and,V

then passing it through a heated die. But, it is to' be understood that the final paraffin and Montan wax treatment are not essential and that the graphite incorporated is suiiiclent to render the jacket non-sticky and self-lubricating.

Electric conductor jackets, when treated ac- .cording to the method herein described and having incorporated therein the improved bituminous, pitch or asphaltic vehicle carrying graphite, is endowed with greatly improved characteristics and the improved character of the Jacket is particularly noticeablev when the conductor is bent on a small radius. Such bending does not tend to disintegrate or rupture the impregnating materials and it is thought that the inclusion of graphite, due to its lubricating qualities, is a material factor in endowing the composition with this desirable characteristic.

While I have described specically the improved product. its method of manufacture and the composition oi saturating or nnlshing material used in the treatment of the `iacket it is to be understood that the disclosure is to be interpreted in an illustrative rather than a limiting sense since variations may be made without departure from the invention as defined with particularity in the appended claims.

What I claimv is:

1. In the manufacture of .insulated wire, the method which comprises enveloping a conductor with an absorbent jacket and subjecting said jacket to treatment in a bath containing stearin pitch, Montan wax, asphaltic material and graphite.

2. In the manufacture of insulated Wire, the method which comprises providing a conductor having an absorbent jaclret and subjecting the jacket to treatment in a bath containing stearin pitch, Montan wax, giisonite, carbon black, slate dust Vand graphite.

3. Inthe manufacture of insulated wire, the method which comprises providing o. conductor having an absorbent jacket and subjecting the jacket to treatment in a bath containing stearin pitch, Montan wax, asphaltic material and graphite, the percentage of graphite in the bath being 'between iift'een and forty percent.4

'4. A conductor having an enveloping jacket ci .iibrous material impregnated with a compound comprising steal-in pitch, montan wats, asphaitic material and graphite, the latter being present in suificient quantity to endow 'the jacket with selilubricating characteristics.

5. A compound for treatment of conductor coverings comprising stearin pitch, Montan wax, as

phaltic material and graphite, the amount oi the latter ranging from fifteen to forty percent of the total.`

6.' A compound comprising stearin pitch, Mon tan Wax, asphaltic material, flake graphite, carbon black and slate dust, the percentage oi graphite being not less than iifteen percent oi the total.

'1. A conductor having an insulating covering.

a Jacket oi' ibrous material enclosing the insulating covering, said jacketbeing impregnated with a flame-resistant and moistureproof composition comprising stearin pitch and containing suiiicient graphite to render the surface of the impregnated material self-lubricating.

B. The conductor of claim '1 in which the graphite comprises between l5 and 40 per cent of said impregnating composition.

9. The conductor of claim 7 in which said impregnating composition also comprises Montan wax and asphaltic material.

10. A conductor having a covering of rubber insulation, a fabric enclosing said layer of rubber insulation, said fabric being impregnated with a flame and moistureprooflng composition comprising a stearin pitch, said composition having suiiicient graphite at its outer Vsurface to render it self-lubricating. f

11. An electric conductor having a covering ot rubber insulation, a braided covering of brous material enclosing said rubber insulation and a iiame and mistureprooiing composition impregnating said braided covering and comprising stearln pitch of between 15 to 40 per cent of graphite at its surface to render said surface self-lubricating.

' JOHN W. OLSON.

Images