US1636748A - Paper-insulated electric conductor - Google Patents

Description

July {F26 "1927.

J. R. LONG PAPER INSULATED ELECTRICI'CONDUCTOR Filed Jan. 12. 1926 XNVENTOR. fiawd-g X ATTORNE Patented July 26, 1927.

UNITED STATES JOHN R. LONG, OF TARENTUM, PENNSYLVANIA.

PAPER-INSULATED ELECTRIC CONDUCTOR.

Application filed January 12, 1926. Serial No. 80,814.

I lhe object which I have in view is the provision of a paper insulated electric conductor which Wlll be able to carry higher voltage and at reduced loss of current, and

which will be more flexible for bending and free from injury therefrom.

In the present practice the electric conductors, such as cables and wires are tautly wound with a. plurality of plies of strips of paper, paper made from old rope fibres being preferably employed to obtain the desirable tensile strength and exterior smoothness necessary to pass through the former or die ofthe winding machine. Paper made from old rope fibres is .used owing to the high cost of new manila fibre. Old rope fibre is usually contaminated with foreign matter, such as'grease, oils, metals, sand, salt, &c., that have accumulated in its previous service, and the presence of such foreign matters impairs the dielectric, properties of the insulation and increases the current loss.

Under the present practice it is impossibleto remove these impurities from old rope stock, and the supply. obtainable, is not only becoming scarcer but is growing more contaminated; and the rope stock is often adulterated in manufacture, frequently carrying a large percentage of slsal, or other inferior fibres. I

In addition to the cui'rent loss due to impurities in the old rope paper, a conductor wrapped with the same shows acertain loss in flexibility owing to the friction between the surfaces'oftightly wrapped layers of the same material.

As a substitute for old rope paper, I have employed paper made from spruce pulp cellulose, so treated as to become mechanically pure, thereby obtaining a higher de-' gree of insulation; but the frictional means employed for winding and tauting the paper about the conductor tendsto accumulate a certain amount of fuz z,1 or lint, resulting in .a roughness of surface which interferes with the passage of the cable through the former or die employed to insure a smooth, uniform ex iternal surface to the cable.

Again, the wood pulp paper presents like surfaces in contact which cause internal friction in the insulating envelope, causing I the conductor unduly to resist bending and resulting in injury to the insulation from bending. v

Attempts have been made to employ paper composed of a mechanical mixture of cellulose, such as wood pulp or jute fibres and old rope fibres, but the impurities in the old fibres impairlthe insulating properties,'and the fault of excess friction between surfaces of like material evinces itself.

In my present invention I provide an electric conductor having an insulating envelope formed of one or more layers of spirally wound strips of paper whose opposite surfaces are formed of different materials, thus minimizing the friction.

For instance the paper covering maybe formed of spirally wound strips of paper whose body is composed of wood cellulose, and one of whose surfaces, preferably the outer surface is formed by a layer of vegetable fibre with the majority of the fibres laid in the general direction of the length of the paper strip to increase its tensile strength. Such vegetable fibres as those of cotton, rice, hemp, ramie, jute and the like may be used.

Thus also I may form the one layer or the body of the paper of jute fibre and the other layer of old rope or other vegetable fibres.

I .prefer to use a mechanically pure Swedish spruce cellulose as the stock for thebody of the paper.

For the surface layer of vegetable fibre I may use such fibres as those of cotton, rice, hemp, ramie, jute and the like, but I prefer to employ old rope fibre.

In the accompanyingdrawings, Fig. l is a broken perspective showing a composite wire cable wrapped with three layers of insulati-ng paper in accordance with my prescut invention, and Fig. 2 is a View in perspective of a short strip of said paper, the two exterior surfaces being shown separated in an arbitrary manner for the sake ofil- 'lustration.

fibre surface on the outside, and in the finished conductor the frictional contact is not between surfaces of like material, but between a surface of cellulose material and a surfaceof rope or other vegetable fibre, and thus the friction is reduced to a minimum, resulting in a conductor of greatly increased fiexibility" and one whose insulating covering Will not wear out paired from bending. r The wound cable will also present asmooth, uniform surface which will pass or be functionally in'1- easily through the former or die without abrasion.

My improved aper is also chea er than paper made who ly of new manila emp or old rope fibres. a

What Idesire to claim is z-.

'1. An electric conductor haying a paper/ insulating envelope formed of one or more spirally wound layers of paper of composite opposite surfaces formed character having of different materials:

2. An'electric conductor having a' palper insulating envelope formed of a plura ity j of layers of spirally wound paperof G0 posite character having its opposite surfaces of different material to minimize friction between the layers. 5

3. An electric conductor havin *-a paper insulating envelope formed 0 spirally wound layers of paper OfCOlDPOSltG character having onesurface, ofcelluloseimaterial and the other surface of vegetable fibres toreduce the friction between'the layers.

4. An electric conductor havin a paper insulating envelope" formed of wound layers of paper of composite character having-one surface of cellulose material" andthe other surface of manila fibre.

layers.

' Signed at Pittsburgh, Pa. this 31st day of December, 1925. r I I JOHN R. LONG.

spirally

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