US2252755A - Method of saturating fibrous coverings on wires, cables, and the like - Google Patents

Description

Aug. 19, l941.- c. Q. VBRUESTLE 2,252,755

.METHOD'OF SATURATING FIBRQUS COVERINGS ON WIRES, CABLES, AND THE LIKE Filed May 13, 1939 COVER/N6 INVENTOR I v c/ikL 0. B 055715- I WIRE v ATT RNEY steps in the course of its manufacture.

Patented Aug. 19, 1941 METHOD OF SATURATING FIBROUS COVER- INGS ON WIRES, CABLES, AND THE LIKE Carl 0. Math, may. N. 1., assignor to Elevator Supplies Company, Incorporated, Rahway, N. 1., a corporation of New Jersey Application May '13. 193a, Serial No. 273,388

1 Claim.

This invention relates to a method of saturating flbrous coverings on wires, cables and the like, and provides improvements therein.

In the manufacture of electrically insulated wires and cables the usual practice is to run the wires and cables with their flbrous coverings 2 through a tank' containing a liquid or liquifled coating material, which tank is very long to enable the coating material to impregnate and saturate the material to which it is applied, and

consequently occupies much floor space.

The tanks have one or more drums therein over which the wire is pulled in numerous spirals or loops. This results in flats on the wire, which are accentuated when the coating material has considerable viscosity, or when for some other reason, the pull on the wire has tobe increased. Moreover, the pulling of the wires over the drums results in densifying or compacting the portion of the wire in contact with the drum, and the drum masks to an objectionable extent the said portion of the wire in contact therewith,-the coating material thereby not having equal opportunity to penetrate the cable or wire covering, and the result being non-uniform coating and penetration of the wire or cable by the coating material.

Moreoverthe coating material is usually heatedv fuel cost, but also frequently necessitates the use of a cooling room or a plant to remove the heat before the wire or cable undergoes subsequent If the wire, after coating, is allowed to stand to cool. a large amount of floor space is required for storing the wire until it has properly cooled.

The present invention provides a method which greatly reduces the size and floor space of the apparatus required for thoroughly impregnating and saturating the fibrous coating on a wire or cable with a saturating material, and also effects coated with the saturating substance or material (which may be done in a short tank, for example) and then pulled through a chamber having oriflces of a form and size to build up a pressure in 1 the saturating material, around the wire or cablesalt is drawn through the chamber, and force the penetration of the saturating material into the pores or interstices of fibrous covering on the wire or cable (as a braided fabric covering) to fill thesame.

An example of apparatus which may be used in practicing the present invention is illustrated in the accompanying drawing, wherein: P

' Fig. l is a vertical sectional view of an apparatus which acts to build up a pressure in. the saturating materiar'around the wire in the chamber when a wire or cable is pulled through it.

Fig. 2 is a diagrammatic view illustrating the application and forceful saturation of awire or cable with a saturating material according to the method disclosed herein.

considerable economies in fuel for heating and. power costs for cooling There is also avery sub- I stantial reduction in evaporation losses, with consequent economies, betterment of health hazards, and simplification of the control of the viscosity, etc., of the coating compound or composition in the coating tank. The improved method also has greater flexibility as regards the speed at which the wire is run through the saturant, wire sizes, and penetration requirements. It also provides a superior product, flats on the wire being avoided,

and uniform penetration obtained.

According to the present invention, the flbrous covering on a wire orcable is first superficially Fig. 3 is. a longitudinal sectional view illustrating a wire in the course of the application of a saturating material thereto and the forced penetration of a braided covering thereon by the saturating material.

Referring to said drawing, numeral l0 designates a reel holding a supply of when! cable; numeral l2 designates a take-up reel through which a pull is exerted .on the wire; numeral H a tank or other suitable means'for applyin the saturating material to a wire; and numeral it indicates a penetration forcing device or chamber. The take-upreel II is motor driven in such a way to exert a pull on the wire, and also to obtain a desired speed of the wire, and to control the pressure of the coating material within the chamber l6.

The ordinary wire for electrical use usually has a rubber or rubber. composition coating, around which there is a woven textile covering or coverings, as a braid of cotton. "Ihe textile covering is usually impregnated with an asphalt V or asphalt. Another common form of insulated wire is one around which textile threads are spiralled, and the threads impregnated with a wax or wax composition.

In Fig. 3' of the accompanying drawing, the example of the wire tobe coated is a rubber coated wire having a braided textile covering thereon. The wire with its braided textile covering has applied thereto a saturating material. such as a blown tar or asphalt, and this is forced to penetrate the pores and interstices of the covering.

The saturating material is conveniently :applied to the covering in a tank, as indicated at ll, Fig. 2, the wire being led into and out of the tank over rollers I8 and i9 submerged in the saturating material. The tank may be and usually is a heated tank for keeping the saturating material in a liquid or semi-liquid condition. The tank may be a comparatively small or short tank (about 3 or 4 feet long, as compared with the tanks which are commonly used having a length of about 20 feet and equipped with drums around which many loops of wire are passed). There is accordingly, not only a great saving in fioor space, according to the present invention, but there is a substantial saving in the quantity of saturating material in use at any one time, and in the fuel required to maintain the mass of liquid or liquefied saturating material at a proper temperature. Moreover, in the large tanks equipped with'drums over which many loops of wire pass, now in common use, the mass of the wire passing through them is heated nearly to the temperature of the bath, and carries out with it a large quantity of heat. By the use of a small tank, according to the present invention, through which the wire may pass, the wire does not have the opportunity to have its temperature raised considerably, or to. absorb and carry oif much heat.

The wire with the saturating material applied to its covering, as indicated'at 22, Fig. 3, is subjected to a pressure step for forcing the coating material into the pores and interstices of the covering. This pressure step is efi'ected by pulling the wire with the saturating material thereon "through a plurality of chambers each of which is partially closed by constructed orifices of a form and size to create a pressure upon the saturating material under the pull of the wire as it passes through the orifices. A chamber device or apparatus, illustrated at I6, is advantageously used in practicing this step.:

The chamber device l6 conveniently comprises a series of blocks 25, 26, 21 having orifices 30, 3|, 32 therein. These orifices are. preferably of progressively diminishing size in the direction of the travel of .the wire, the size of the last coating material in the tank It, as indicated ih Fig. 2. The chamber device could nevertheless be submerged in the saturating material.

Referring to Fig. 3, as the wire covered with the saturating materialis pulled through the orifices 3ll, et seq.,some of it, as indicated at 42, cannot pass through the'orifice with the wire,

' and the drag of the wire on the saturating material as it passes into and through the orifice 30 (after the chambers 35 and 36 have been filled) produces a pressure on the saturating material which forces it into the pores and interstices of the fibrous covering on the cable. This mode of operation takes place in front of each of the succeeding orifices. In passing through orifice 3| which is somewhat smaller than orifice 30, some of the saturating material is squeezed back by the restriction of the orifice. This builds up a pressure in the chamber 35 in front of the orifice 3| and in-the orifice. Additional pressure is therefore produced in the chamber 35 and in the orifice 3| on the saturating material, forcing it to penetrate the pores and interstices in the covering of the wire, between stranded wires constituting cables, etc. As the wire passes through orifice 32, which is smaller than the preceding orifice, some of the saturating material thereon is squeezed back. This creates a pressure in chamber 36 in excess of that in chamber 35,

and the pressure in chamber 36 at and. around the orifice 32 is such as to exert a strong pressure acting to force the saturating material into the pores and interstices of the wire covering, etc. The number of the orifices may be increased to obtain the efi'ect desired.

In order to guard against excessive pressure in front of the orifices 30, et. seq., relief valves.

wrinkle if pressures are too great. Twenty-five pounds pressure per square inch, for example, I find to be the limit for one kind of wire. With other types I have found for example that sixty pounds pressure can be used. Much depends on the character of the wire and its covering and the way in which the braid is applied, as to the pressure which can be applied without causing the braid to wrinkle.

The blocks with the orifices therein may be repeated to give a desired pressure. The amount of pressure can also be controlled by the speed at which the wire is pulled through the orifices. By increasing the speed at which the wire is pulled through the orifices, the pressure in the saturating material around the wire in front of the orifices can be increased. Regulation of the speed of pulling the wire through the orifices therefore provides a convenient mode of regulating the pressure on the saturating material around the r wire.

Alternatively. or conjunctively, the pressure in the chamber device may be regulated by regulating the sizes of the orifices for a given size wire. An increase of the size of the last orifice in the direction of the running of the wire decreases the pressure not only in the chamber ahead of that orifice but also in each of the chambers ahead of it. Also, by increasing the size of the first orifice leaving the other orifices unchanged, the pressures in all of the chambers will be decreased. By

increasing the sizes of each of the orifices ahead of the first orifice, the pressures in all of the chambers will be decreased. Conversely, a decrease in the size of an orifice, or orifices, increases the pressures in the chambers.

Alternatively or conjunctively, the pressure in the chamber device may be regulated by increasing or decreasing the number of the chambers.

' The addition of a chamber and an orifice ahead of it, with a given number of," chambers and orifices, will increase the pressures in all of the chambers following it; conversely the subtraction of a chamber and orifice will decrease the pressures in all of the chambers following it.

7 As an example of the speed at whichthe coating or saturating of wire is now done, wire sizes around #14, having a-rubber insulating coating, and three cotton braids, are run at speeds of around 300 feet per minute. With less braids the speeds are greater. With the present invention Moreover, in coating braided wire, I

considerably higher speeds may be obtained for comparable wire sizes. With the present invention using a pressure device about a foot in length, it is possible to accomplish as much and more than is accomplished by the commonly used saturating tanks many feet in length; and in order to obtain greater speeds, little if any lengthening of the pressure device would be required as compared with considerable lengthening of the commonly used saturating tanks.

Moreover, as before stated, the wire after pass ing out of the pressure device l6, contains only a small amount of heat to be dissipated, and can ered wire, pulling the covered wire with. the liquified impregnating substance adhering thereto through a confined chamber having constricted wire entrance and exit openings, then pulling the covered wire with the liquified impregnating substance adhering thereto, through a second confined chamber having a constricted wire exit opening, the second chamber being in communication with the first chamber through the exit opening of the first chamber, the. liquified impregnating substance which adheres to the covered wire being carried by the pulled wire into said be subjected to any subsequent steps which it may be desired to perform upon it, without cooling or with a comparatively small amount of cooling.

The method may be carried out by other means and by other modes than that herein specifically illustrated and described.

What is claimed is:

A method of saturating the covering of fibrous material wrapped on a wire with a plastic substance, comprising heating a plastic impregnating substance to liquify it, applyingthe heated impregnating substance to the surface of the covchambers. in excess of the amount carried out by the covered Wire, regulating the speed at which the covered wire is pulled through the confined chambers to obtain an increase of pressure to a desired maximum operating pressure, to produce a substantially higher pressure in the second chamber than can be obtained in a single chamber, and to force the impregnation at successive- 1y increased pressures, and limiting the application of the hot liquified impregnating substance to a time interval so as to increase the temperature of the wire only to a small degree.

CARL O. BRUES'I'LE.

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