US2316572A - Process of finishing electric conductors - Google Patents

Description

A ril 13, 1943. c. EATON PROCESS OF FINISHING ELECTRIC CONDUCTORS nyaomzou FMKUdQu u math-mm W Z L waommm ZPEm Mai: hzim 63m Filed April 21, 1939 FM v I I, M 1 ym c aw g w MH, .m Ms W? 1 y IO AH, I. J \a Patented Apr. 13, 1943 rnocsss or rmsnmcsnscraro coNnUc'rons Irving C. Eaton, Nichols, Coma, assignoi' to General Electric Company, a corporation oiNew York Application April 21,1939, ,serial No. 269,280 T Claims. "(01.117-92) v g r the wire is run continuously without anyjinter- My invention relates to a process for applying a finishing coating to insulated conductors, and more particularly to a process for continuously applying a' moisture-resisting, flame-retard'ing and colored finish to insulated conductors, for example, building wire. I

According to former processes such finishes were applied in individual steps, and it was necessary'to allow a setting period for each of the coatingsbefore the applicationoi the succeeding one in order to prevent mixing and consequent ruptionirom thesaturating tank to the tank containing the flame-retarding compoundand that the stearine pitch is applied directly over the asphalt. saturant. 1 The stearine pitch is maintained at temperatures ranging from approximately 300 F. to 325 F. v

Upon passage 01' thejacketed conductor from the'tank of flame-retarding compound, the excess loss of desirable properties such "as flame resistance. Thismeant'a considerable loss in time in finishing the conductor and an increase in cost due to the numerous handling operations incident to'carrying out the individual steps in applying the finishing coats.

The object of my invention is the provision of a new and improved process whereby the moistum-resisting, flame-retarding and colored finishes may be applied continuously on after the other without any interruption. in the-treatment oi the insulated conductor. 1 I I In the accompanying drawing, Fig. l-shows an assembly of apparatus which permits, carrying out my continuous process; and Fig. 2 is a view of an insulated conductor finished in accordanc with my process.

In accordance with my invention, an insulated conductor I0 is subjected to a continuous finishing process and is unwound continuously from a take-oi! capstan II and after being subjected to the various finishing processes is wound up on a take-up capstan II. The conductor I0 is provided with any convenient jacket of insulating material, for example, a fibrous insulating material such as cotton braid.

The insulated conductor passes over a guide pulley l2 and is then wound severaltimes around a saturating reel or drum mounted in a saturating tank H. The tank I4 contains a moistureresisting compound I 5, for example, a bituminous compound containing asphalt; By being passed several times around the drum l3, the jacketed wire isimmersed in the saturant for a time interval sufllcient to thoroughly impregnate the fibrous covering with the bituminous compound. The moisture-resisting compound should be applied at a temperature of approximately 350 F.

'After passing the wire through the moistureresisting compound th excess material is removed by means of a wiper l8 and the wire is then guided by means of the rollers l! to a tank I I6 containing a flame-retarding compound 10, for example, stearine pitch; It should be noted that material is removed by a wiper 20 andthe coated dered material '22, for example, talc and isthen wound around a drivingcapstan 23. A wiper 24 removes; excess tale. The powdered talc forms-a fine protective surfaceand prevents the-coated jacket from sticking to the driving capstan. 'If desired, the talc coating may be omitted without in th least ailecting the quality of the finished product, for example, if the driving capstan is omitted.

r The coated conductor passes from the driving capstan to a tank, containing a quantity of paint 28 which is applied directly over the coatings oi flame-retarding and moisture-resisting compounds. I employ a quick drying paint using synthetic resins having solvents miscible with water, for example, a chlorinated rubber paint.

Excess quantities of the paint. ar removed by a.

travels backand forth through the water bath' several times and then passes'out oi the tank through an air blast 3| which removes the excess water from the conductor and dries it. Fresh water is circulated through the tank 28 continuouslyby means of the inlet and outlet pipes 32 and last the temperature from which it comes from thewater supply.

One purpose of the water bath is to dry the paint. This is accomplished due to the fact that the paint contains a water soluble solvent, and this solvent is removed from the paint as the conductor passes back and forth through the water bath permitting the pigment to dry on the wire.

In addition 'to drying the paint, the water bath A cools the wire which has been heated by the hot wire or adhesion between the adjacent coatings of the wires.

In some instances it may be desired to print or mark the building wire for the purpose of identifying the size of the wire or the source of manufacture. In such cases the wire is passed directly from the water bath through a printing machine 33 where any suitable identification means may be applied to the painted wire. The printing is done with a colored ink contrasting with the color of the paint coating.

After being printed the wire is passed over a guide pulley 34 to a tank 35 containing wax or paraflin 36 which provides a slick finished coating on the painted wire. The'wax provides, a smooth satin finish for the wire and gives the wire a fishable outer coating making it particularly adapted for drawing within a metallic conduit. A wiper 31 removes any excess wax or paraflin as the wire is wound around a driven capstan 38 before being coiled on the take-up.

capstan II. The wax or paraflln is applied at a temperature of approximately 160 F. In those cases where the wire is not printed the outer slick finish of wax or parailin is applied directly over the paint.

According to my invention, the wire is run continuously through the moisture-resisting and flame-retarding compounds without the necessity of interrupting the process to permit the setting of each of these layers of compounds prior to application of theother, such as was the case according to former practices. This is due to the fact that the wire is impregnated at a speed such that the water bath 29 cools the wire before the flame-retarding and moisture-resisting compounds have had an opportunity to intermix such as might destroy the efiectiveness of the flame-- retarding compound. Unless intermixing of these compounds is prevented, the coatings willbecome sticky and the conductor will not pass the flame test for flame-retarding finishes. By applyinga paint having a water soluble solvent immediately over the flame-retarding compound and then removing the solvent by means of a water bath, it is possible to paint directly over the flame-retarding compoundwithout the necessity of setting this compound prior to application of the pant because the water bath not only drieskthepaint but cools the wire preventing intermixingb! the paint and flame-retarding compound. Moreover, the use or a paint of the type mentioned in combination with the water bath makes it unnecessary to interrupt the processto permit drying of the paint prior to application of the finishing wax, such as was thecase according to former practices, when it was necessary to pass the painted wire through a drying chamber before application oi the finishing wax. In painting over the impregnating compounds, any suitable colored paint may be employed including the light colored paints which, it has been found, are very effective in covering the black colored impregnating compounds. v

The conductor is run continuously through the various finish coatings without the needot intermediate setting steps such as would necessitate special handling. For a No. 14 wire, the conductor may be subjected to the finishing process at speeds of approximately 1'75 to 275 feet per minute. The process results in a conductor having an excellent moisture-resisting and flame-retarding finish and one on which the paint will not peel or flake off upon twisting or bending of the conductor.

What I claim as new and desire to secure'"-b Letters Patent of the United States is:

1. The process of treating the insulating jacket of an electric conductor which comprises apply} ing a hot layer of moisture-resisting compound including bituminous material to said jacket, applying a hot layer. of flame-retardng compound immediately over said moisture-resisting compound, applying a coating of paint having a water soluble solvent over said flame-retarding compound and then immersing said jacket in a water bath to dry said paint and to cool said layers to prevent blending of said compounds.

2. The process of treating the insulating jacket of an electric conductor which comprises applying a hotv layer of bituminous saturant to said jacket, applying a hot layer of stearine pitch, applying a coating of paint having a water soluble solvent, and then immersing said jacket and layers in a water bath t0 dry said paint and simultaneously cool and prevent blending of said layers of bituminous saturant and stearine pitch.

3. The process of treating the insulating jacket of an electrical conductor'which comprises applying a hot layer of moisture-resisting compound to saidjacket, applying a hot layer oi flame-retarding compound including ,stea'rine pitch immediately over said moisture-resisting compound, applying a coating or paint having a water soluble solvent over said flame-retarding compound and then immersing said jacket in a water bath to dry said paint and to cool said layers to prevent blending of said layers.

, 4. The process of treating the insulating jacket of an electrical conductor which comprises applying a hot layer of moisture-resisting material to said jacket,applying a hot layer '01 flame-retarding compound immediately over said moisture-resisting compound, applying a coating of paint having a water soluble solvent over said flame-retarding compound, andthen immersing said Jacket in a water bath to remove said solvent todry said paint and' to cool said layers to prevent blending of said material and compound.

5. The process of treating the insulating jacket of an electrical conductorwhich comprises applying a hot layer of bituminous saturant to said Jacket, applying a hot layer of stearine pitch immediately over said asphalt 'saturant, applying a coating of paint having a water soluble solvent immediately over said stearine pitch, immersing said jacket and layers in a water bath to remove said solvent and dry said paint and simultaneously-cooled to prevent blending of said layers of bituminous saturant and stearine. pitch and then applying a coating of waxlike material over said paint to provide a slick finish to said conductor.

- IRVING C. EATON.

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