US1762941A - Paper-insulated conductor - Google Patents

Description

June 10, 1930. E. B. woo'o PAPER INSULATED CONDUCTOR Filed May 29, 1926 2 Sheets-Sheet 1 'IIIIIIIIIII/I/IIl/l/III June 10, 1930. E, 3 901 1,762,941

PAPER INSULATED CONDUCTOR Filed May 29, 1926 2 Sheets-Sheet 2 five/7hr.- frnes? 5; Wood Fatented June 1'0, 1930 UNITED s'rArEs PATENT; oFncr.

' 3. W001), or cnarrrul, n'nw msnv, assrenon. T BELL 'rnmrnom mozwroams, mcoaroaa'rm, or mrw roux, n. Y., A conronarron or nnw Yoax YAPEB-INSULATH) CONDUCTOR Application fled Kay 29, 1928. Serial 1T0. 112,532.

This invention relates to pa r insulated conductors and a method of m 'ng them.

An object of this invention is an inexpensive, substantially moisture-proof paper insulated conductor capable of withstanding severe service strains.

The method of applying the paper insulation to the conducting core does 'not form a part of this invention since the method used is that disclosed in the copendin a plication of H. G. Walker and A. T. Marci, 547,924, filed March 29, 1922, Patent No. 1,615 417 dated Jan. 25, 1927. The moistureproofing or impregnating process also is disclosed in the copending ap lication of D. R. gr2o5bst, SerialNo. 68,058, ed November 10,

The conductor of this invention has its insulation reinforced by the application of a serving of yarn which partially embeds itself in the somewhat moist paper coating, previous to the moisture-proofing by impregnating with cellulose acetate lacquer.

The invention will be better understood from the following description together withthe attached drawings forming a part thereof and in which,

Fig. l is a diagrammatic representation of the apparatus required for coating and impregnating the conductor;

ig. 2 is a top view on an enlarged scale of a art of the pulp applying apparatus;

ig. 3 is a side view of the pulp former;

Fig. 4 is a section of the same on line 44 of Fig. 3;

Fig. 5 is a view in section of a part of the squeezing roll;.

Fig. 6 is a view in section of a part of the main drum;

- Figs. 7, 8, 9 and 10 represent different stepsin the formation of the pulp on the conductor; and Fig. 11 is a side view of the insulated conductor.

Referring now garticularly to Fig. 1, the core 74 to be coate is fed from a supply reel 20, over an idler roll 21 and-thence around a drum 22 which is partly submerged in liquid containing ulp within a semi-spherical trough 23. e drum 22 comprises a pair of sheet metal sides 24, 6) and a peripheral erial Nothe tank 23, as indicated by portion 25 secured thereto. The portion 25 is provided with a plurality of relatively large perforations 26 which are covered with a narrow strip of fine wire mesh 27. The core, in passing around the .drum, lies upon the wire mesh 27 The drum 22 has a centrally disposed tubular axle 28 which is rotatably mounted in suitable bearings 29 carried by a framework 30 which supports all the elements ofthe a paratus.

In or or to apply pulp to the core as it passes overthe drum 22, the. pulp mixture within the drum is maintained at a lower level than that of the level of the pulp mixture in dottedlines A and B, respectively. This difference in levels is maintained by a siphon pipe 31 which has its inlet opening submerged in the pulp mixture within the drum 22 and its discharge through the tubular axle 28. A continuous back into the suppl tank 32, in any suitable manner. As the rum 22 carries the core thereon through the tank, the liquid in tank 23 will pass through the wire mesh 27 and perforations 26, due to the difference in levels of liquid within the drum and the tank 23 straining the pulp onto the outersurface o the wire mesh and applying the pul' to the core supported thereon. In order to E e the wire mesh clean prior to its reception 0 the core, and a new coating of pulp, it is washed by a jet of water, under pressure, which is su i plhedthrough a nozzle 33.

e drum 22 is rotated in the direction indicated b the arrow. The core 74, with a coating 0 pulp thereon, leaves the drum at the top thereof and the force of gravity, the surface tension of the liquid in the pulp mixture, and the felting of the pulp fibres cause the pulp to surround the'core andv clin to it mounted between a pair of brackets 37 secured to an upright standard 38 supported by the framework 30. The shaft carrying the roll 36 is driven through a pulley attached thereto which is actuated by a motor 39 in any suitable manner, as by means of belts 40 and 41. The core is drawn from the supply reel 20 over the drum 22, causing it to rotate, by the squeezing rolls and 36. 1.

The auxiliary roll-34, as shown in Fig. 5, is a hollow sheet metal drum having a pcripheral slot covered with a strip of fine wire mesh 42. It has been found preferable to employ the auxiliary roll 34 and to make it foraminous where it engages the core and pulp coating thereon in order that the free liquid, so to speak,mav bestrained ofi away from the core and coating. If such a roll were not provided, the excess liquid would tend to wash ofi the pulp coating, since at this stage the ulp coating is very soft and easily removed from the core. With the free liquid removed, the coating has greater strength due to a closer felting of the fibres so that when the core and coating are passed through the squeezing rolls, the coating will not be torn from the core.

The squeezing rolls ma be formed of rubher and forced together y any suitable adjustable means to place the proper pressure on the core and pul coating as they pass between the rolls.

ese rolls remove the greater rtion of liquid from the pulp mixture an form the ulp into a thin ribbon which extends latera y from each side of the core as shown in Fig. 8. This squeezing operation also mats or felts the fibres into more intimate relation thereby increasing theafter the forming action is completed isv shown in Fi 9 and 10. The former causes a thorou h mtermingling of the pulp fibres and mol the coating to conform to the shape of the core. 6

The former, shown in detail in Figs. 3 and 4, comprises two on - shaped collars 43 and 44 hel together an in spaced relation by means of rods 45. Integral with said collars 43 and 44 are sleeves 46 and 46' respectively, which are rotatably mounted-within suitable bearings in the standards 38 and another pair of standards 47 supported by the framework 30. Two plates 48 and 49 have projecting tongues which are bent around two of the rods 45 to pivotally support the rcilates in opposed relation to eac other.

ompression s rings 50 engage the rear faces of plates 48 an 49 and ten to force them to,-

gether. The springs 50 are put under the requisite compression by means of adjusting screws 51 which are mounted in brackets 52 secured to the rods 45. The ends of the plates 48 and 49, adjacent the squeezing rolls 35 and 36, are flared outwardly so as to present a smooth surface to the core and pulp coating as they pass from these rolls through the sleeve 46 and between the forming lates 48 and 49. The core passes from the orming plates through the sleeve 46.

The plates 48 and 49 are rapidly rotated around the core having the pulp coating thereon, through the medium of a pulley 18 secured to the sleeve 46, the pulley being driven by the motor 39 through a belt 17.

The forming plates 48 and 49 wrap the projecting edges of the pulp ribbon about each other and around the core in much the same manner as though the core and pulp ribbon were rolled on a tabletop with the palm of the hand.

As the coated core leaves the former, a serving-head 55 wra s a layer of yarn 76 over the pul coating. ince the pulp coating is still so and moist this yarn as shown in Fig. 11 will partially embed itself in the coating thereby greatly strengthening it. This yarn may be of any suitable material and of any convenient size and is served so that there is no overlapping or portions of unprotected pulp coating. The serving usually consists of about seven or nine strands.

If desired, strands of distinct colors may be introduced into the yarn to act as markers.

The core with its formed coating passes from the serving-head to a mechanism for drying out the coating. The means shown for this operation is a pair of wide hollow drums 52 and 53 heated internally and having a plurality of grooves 53 formed thereon (Fig. 2) which receive the core. Guides (not shown) are provided for drawing the core over first one drum and then the other until the coated core has traversed all of the grooves on both drums, after which it is drawn over a suitable pulley or other guiding means 3 to an impregnating tank 4 containing a cellulose acetate bath 5. The impregnatin tank 4 is preferably composed of a suita le electrically conducting, cellu-' lose acetate-inert material such, for example, as brax.

From the pulley 3, the conductor passes under pulley 6, up and over pulley'7, down and under pulley 8, up and out of thebath and tank and over pulley 9. From the tank 4 the conductor passes to a second impregnating tank 10 and drying chamber 11 and then to a suitable take-up reel 12.

The'take-up reel 12 is'preferably formed of an electrically conducting material so that it may be employed as one of the electrodes for applying potential between the conductor and the bath containing the conductor during the impregnation treatment. When used 1n this manner, the conductin core of the conductor being treated is attac ed to the metallic core of the take-up reel 12. A suitable binding post is attached to the impregnating chamber 4 such as shown at 13.

During the passage of the conductor throu h the impregnating tank 4, a potential is applied, as set forth in the above mentioned Brobst application, between suitable electrodes, such as the metallic reel 12, to which the conducting core of the conductor is electrically attached, and the binding post 13; the reel 12, being preferably made the anode or positive electrode. With the application of such a potential between the conductor and the container holding the conductor durin the impregnating treatment, it has been foun that the cellulose acetate solution penetrates finish is produced if the conductor is passed through a plurality of additional impregnation ste s without the application of a potential. herefore after leaving the tank 4, the conductor is drawn under a suitable guide pulley 14 and through a cellulose acetate bath 15 contained in the tank 10. The distance traveled by the conductor after leaving tank 4 and before entering the bath 15 should be so short that there will be no deposition of moisture on the conductor.

The conductor then passes through the drying chamber 11 which may be, for example, an electric furnace comprising a refractory core wound with suitable resistance wire 71 and enclosed within a second refractory tube 72 over which suitable heat insulating material 7 3 is placed.

The insulation of the conductor after passing through the chamber 11 should be thoroughly dry. This may be accomplished by maintaining a high tem rature 1n the furnace or by giving the con uctor several passes in the furnace.

What is claimed is:

1. An electrical conductor comprising a metallic core, a coating of loose fibrous material thereon and a layer of textile material enclosing said fibrous material coating, said coating and said layer of textile material being impregnated with cellulose acetate.

2. An electrical .conductor comprising a conducting core, a coating of paper pulp thereon and a serving of yarn enclosing said coating, said coating and said serving being impregnated with cellulose acetate.

3. An electrical conductor comprising a conducting core, a coating ofpaper pulp thereon and a layer of textile material en- 70 closing said paper pulp and partially embedded therein, said pulp and said layer of textile material being impregnated with cellulose acetate.

4. An electrical conductor comprising a conducting core, a coating of paper pulp thereon and a serving of cotton arn enclosing said pulp and partially embedded therein, said coating and said serving being impregnated with cellulose acetate.

5. A method of coating 9. core which consists in applying wet pulp to the core and causing it to con orm to the shape of the core, enclosing said pulp, while moist, with a serving of textile material, drying said pulp and textile material, impregnating said pulp. and said textile material with cellulose acetate and again drying the combined core covering.

6. A method of coating a' core which consists in applying wet pulp theretoand molding it to conform to the shape of the corei wrapping a serving comprising a plurality o strands of textile material around said ulp with sufiicient force to cause the strand; to be partially embedded therein, drying the pulp and textile material, impregnating said pulp and strands with cellulose acetate and again drying the combined core covering.

7. A method of insulating an electrical conductor which consists in applying wet paper pulp' to the conductor core and molding the pulp to conform to the shape of the core, wrapping a serving comprising a plurality of strands of cotton yarn around the pulp, while it is still moist, with sulficient force to cause the strands to be partially embedded therein, drying the pulp and yarn, subjecting the conductor and covering to a bath of cellulose acetate while maintainin a potential difi'erence between the bath and t e core and thoroughly dr ing the combined core covering.

n witness whereof, I hereunto subscribe my name this 25th da of May, A. D. 1926.

E NEST B. WOOD. 11s

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