Oct. 29', 1946. 2,410,126 J. W. OLSON MACHINE FOR'IMPREGNATING ELECTRIC INSULATION Filed Sept. 16, 1943 MOL TE1V 6'4 TUE/4N T IINVENTOR. Q1 0 Ly.” W‘ 011% ATTORNEYS Patented Oct. 29, 1946 2,410,126 UNITED, STATES PATENT OFFICE FOR IMPREGNATING ELECTRIC INSULATION John W. Olson, Hastin gs-on-Hudson, N. Y., as signor to Anaconda Wire and Cable Company, New York, N. Y., a corporation of Delaware Application September 16, 1943, Serial No. 502,631 1 '9 claims. (01. 91_13>, This invention relates to insulated electric con ductors, and has for its object the provision of certain improvements in saturating or impreg nating the ?brous insulation of such conductors with a bituminous or asphaltic saturant. Certain types of electric conductors and cables are insulated with ?brous material, such as paper, cotton'and the like, impregnated with a Water 2 the United States patent of'Johnson and Olson No. 2,228,766, there is disclosed a combined and simultaneous drying and evacuating of the?brous insulation with immediate impregnation by the saturant. In passing the dried and evacuated covered Wire immediately and directly into the hot saturant, atmospheric pressure is permitted to force the saturant to a considerable height in At ‘ normal 'room‘ temperatures, the saturant is usu 10 an upright evacuated chamber, thus, in eiiect, sealing the end of the chamber communicating proo?ng bituminous or asphaltic-saturant. ally a solid or very viscousv material,’ and it is with‘ the bath of hot saturant. Such simultane hencethe ‘usual practice to heat the saturant to ous drying and evacuating requires careful regu -a temperature at which vit is a mobile liquid, lation and control to satisfactorily attain the two usually about, 350-375“ F. When the ?brous in objectives. , sulation is immersedv in this hot molten saturant, 15 The present invention contemplates an im excessive moisture ‘in the ?brous material is proved apparatus for impregnating the ?brous promptly volatilized, frequently with explosive insulation of electric conductors and cables with violence. Under normal'atmospheric conditions, a hot saturant, particularly of the bituminous or the ?brous insulation usually contains 4-5% of asphaltic type. More particularly the invention moisture,’ vand when such ?brous insulation is 20 aims to provide an improved apparatus for seal immersed in the hot saturant a substantial pro ing the exit or rear end of a vacuum chamber in portion, if not all, of, this moistureis volatilized direct operative communication with a hot satu with» attendant objectionable ebullition and foam rant ‘bath beneath the surface thereof. In ac ing of the bath of hot saturant. The ?brousin cordance with the invention, the electric con sulation is frequently a hard, tough, dense mate 25 ductor surrounded by, or covered with ?brous rial such askraft paper, and evenwhen substan insulation is drawn through a die loosely sur tialy dry such materialis dif?cultly and often rounding it and positioned at the exit end of a incompletelyimpregnated with the saturant. In vacuumcham'ber into a bath of hot saturant ‘in ‘other cases the ?brous insulation isa'a compara tively soft porous paper, such as towelingstock, 30' direct communication with the vacuum chamber, and saturant drawn toward the die by the vacuum crumpled, and twisted about the conductor, and within the chamber is arti?cially chilled. The , characterized by a multiplicity of minute inter thus chilled saturant cooperates with the die and stitial spaces which are di?icultly ?lled with the the covered conductor traveling therethrough to saturant solely-by capillary action. ' eiic-ctively seal the exit end of the vacuum cham Bulk-drying of the ?brous insulation prior to ber. _The invention further contemplates a novel impregnation has heretofore been commercially combination of apparatus .for carrying out the l practiced. > In accordance with the customary practice, the conductor covered with the ‘?brous insulation is wound on reels and dried-for about 16 hours in a dry kiln at a temperature of about 200-2500 F. The covered wire is usually tightly wound on the reel to a radial thickness of about one foot. The inner turns on the reel are seldom satisfactorily dried, and frequently contain up- to 3% of moisture, Moreover, due to the physical discomfort in entering the drykiln, the workmen usually take out two or more reels at a time, and often appreciable moisture is 're-absorbed bythe ?brous material while the reel is exposed to the atmosphere awaiting to be .run ‘through the ' saturant. Vacuum oven drying has also been proposed for drying the ?brous insulation prior to impregg nation with the hot saturant, but this hasvproved foregoing improvements in impregnating ?brous insulation with a saturant. '. The foregoing‘ and other novel features of the invention will be better understood from the fol-' lowing‘ description taken in conjunction with the accompanying drawing, in which Fig. lgis. an elevation, partly in section, of a co-mbinationof apparatus embodying the inven tion,: and‘ particularly adapted for practicing the aforementioned improvements in impregnating ?brous insulation with a saturant, and ' Fig.2 is, an enlarged sectional elevation of the end‘of the Vacuum chamber, in theapparatus of Fig. Loommunicating with the saturant. The, drawing illustrates the impregnation of a layer of ?brous insulation 5 surrounding and covering an electric conductor 6, either stranded little, if any, better than simple kilndrying. - In 55 or solid, With ahot molten saturant l’, The cov~ ered conductor is drawn (in thedirection of, the 2,410,126 arrows) from an unwinding reel or the like (not shown) through the bath or saturant onto a wind ing-up reel or the like (not shown) in a substan tially continuous manner. Within the bath of 24 near the forward end of the device. The dies l3 and [9 may be of different sizes to accom modate different sizes of covered conductor. As previously stated, the covered conductor makes ~ saturant, several convolutions of the covered con ductor are drawn over the surface of a rotatably mounted drum 8. The drum 8 may, if desired, be ‘ appropriately driven by any suitable source of a tight fit in the die l3 and a loose fit in. the die l9. In practicing the invention the covered con ductor is drawn through the sealing die 13 into the vacuum chamber II. In its travel through power, or it may rotate freely and all the power 10 the vacuum chamber, air and other gases are required to draw the covered wire through the apparatus may be applied to the aforementioned winding-up reel. The rate of travel of the con ductor and the number of convolutions wound around the drum 3 are correlated to provide a sufficiently long immersion period to completely, and satisfactorily impregnate the ?brous insula almost completely removed from the interstitial spaces of the ?brous insulation. The evacuated covered conductor is drawn through the exit die IQ of the vacuum chamber and immediately con tacts the saturant which is drawn up the exten sion 11 into the prolong [6 as a result of the vacuum and the comparatively loose fit between the covered conductor and the die 19. However, the saturant will not pass beyond the die l9 into the vacuum chamber, because of the cooling ef tion. With a hot molten saturant of bituminous or asphaltic nature maintained at a temperature of about 350-375" F., immersion times of from 6 to 20 minutes are common. It is to be unden fect of the water jacket 20. The arti?cial cooling stood, however, that the invention is not limited at the exit end of the vacuum chamber chills to saturants of this nature, but is applicable to the saturant in the adjacent part of the prolong any kind of saturant for the ?brous insulation of IE to a very viscous and almost solid condition, electric conductors and cables. The saturant ‘i is and this chilled saturant cooperates with the die contained in a tank 9. A wiper I!) secured to one 25 19 and the traveling covered conductor to- ef side of the tank removes excess saturant from the fectively seal the exit end of the vacuum chamber. covered conductor as it is drawn from the tank. At the same time, the travel of the covered con It will be understood that the drum 8 is provided ductor through the die IE! keeps the die clear, and carries back into the hot saturant in the > with a “pusher” device of conventional construc tion for properly aligning the ?rst and last con prolong or extension any accumulation of chilled volutions of covered conductor thereon with the saturant that might otherwise tend to clog the respective points of supply and withdrawal. die. The exit end of the vacuumtube is thus In accordance with the embodiment of the in sealed by the die 19, and the traveling covered vention illustrated in the drawing, the covered conductor in conjunction with the chilled satur conductor is drawn through an'evacuating device 35 ant surrounding the covered conductor as it en immediately preceding its immersion in the bath ters the prolong I6. of hot saturant. The evacuating device comprises The invention provides a simple and effective an elongated vacuum chamber H connected by a apparatus for saturating or impregnating the pipe [2 to an air pump or other suitable means 40 ?brous insulation of electric conductors and ca (not shown) for maintaining as high a vacuum as bles with hot molten saturant. Evacuating and possible in the chamber, say approximating 30 impregnating are carried out in a substantially inches of mercury. In practice, the vacuum continuous and rapid manner. The sealing of chamber H may be from 3 to 5 feet in length, or the exit end of ‘the vacuum chamber by the even longer if necessary. It is preferably cylin chilled saturant in cooperation with the adjacent drical with a sectional diameter several times the die is simple, effective and automatic. The ap diameter of the largest covered conductor to be paratus is of simple construction and of suitable passed therethrough. A removable steel die I3 proportions for mill operations. The dies l3 and is mounted at the entrance or forward end of the vacuum chamber, and is secured in position by a 19 are readily changed, and no loss of time is involved in changing these dies to conform to threaded nut I4. The traveling covered conductor 50 covered conductors and cables of di?erent sizes. ?ts tightly in the die l3 and effectively seals this I claim: end of the vacuum chamber. The exit or rear end of the vacuum chamber has an inner shoulder l5 and a prolong Hi to which is coupled an extension I‘! extending below the sur face of the bath of saturant. The diameter of the prolong and extension may be somewhat less than the diameter of the vacuum chamber, but 1. The combination with means for holding a hot saturant bath for impregnating ?brous insu ) lationsurrounding an electric conductor, of an elongated vacuum chamber operatively commu nicating with said chamber and having a remov able die at each end thereof for sealing the ends of the chamber when the conductor with its cov still sufficient to freely accommodate the largest ering of ?brous insulation is drawn through the covered conductor to be passed therethrough. 60 chamber and the saturant in a substantially con The extension is coupled and secured to the pro tinuous manner. 2. In the combination of claim 1, a tubular long by a threaded nut 18. Aremovable steel die I!) abuts against the shoul extension communicating at one end with and der l5 and is ?rmly held in position by the travel ing covered conductor which ?ts loosely in this die. A water jacket or chamber 20 surrounds the die I9, and serves to arti?cially cool the die. Any other suitable means for arti?cially cooling the die l9 and the exit end of the vacuum chamber may be provided. An opening or manhole 2i and a cover 22 therefor are provided in the vacu um chamber near the exit end for permitting ac cess to the chamber when changing the die l9. removably attached to the vacuum chamber and extending at the other end into and beneath the surface of the saturant. 3. In the combination of claim 1, a tubular extension communicating at one end with and removably attached to the vacuum chamber and extending at the other end into and beneath the surface of the saturant, andv a man-hole in the vacuum chamber approximate the end attached to said extension for facilitating access to the The evacuating device is supported by a bracket 23 secured to the side of the tank 9 and a post 75 adjacent die, 2,410,126 4. In the combination of claim 1, arti?cial cool ing means associated with the die in that end of the vacuum chamber adjacent the saturant bath, >5. The combination with means for holding a hot saturant bath for impregnating ?brous insu lation surrounding an electric conductor, of an elongated vacuum chamber having one end in communication with the saturant bath beneath ' 6 8. The combination with means for holding a hot saturant bath forv impregnating ?brous insu lation surrounding an electric conductor, of an elongated vacuum chamber, a tubular extension communicating at one end with and removably attached to the vacuum chamber and extending at the other end into and beneath the surface of the saturant, a die at the forward end of the the surface thereof, a die at the forward end of 10 chamber adapted to ?t tightly about the covered conductor, a die at the rear end of the chamber the chamber adapted to ?t tightly about the cov adapted to ?t loosely about the covered con ered conductor, a die at the rear end of the ductor, and a water jacket operatively surround chamber adapted to ?t loosely about the covered ing the die at the rear end of the vacuum cham conductor, and arti?cial cooling means associated ber. with the die at the rear end of the chamber. 15 9. The combination with means for holding a 6. The combination of claim 5 in which each of the dies is removable. ' 7. The combination with means for holding a hot saturant bath for impregnating ?brous insu lation surrounding an electric conductor, of an elongated vacuum chamber, a tubular extension communicating at one end with and removably attached to the vacuum chamber and extending‘ at the other end into and beneath the surface of the saturant, a die at the forward end of the hot saturant bath for impregnating ?brous insu lation surrounding an electric conductor, of an elongated vacuum chamber, a tubular extension communicating at one end with and removably attached to the vacuum chamber and extending at the other end into and beneath the surface of the saturant, a removable die at the forward end of the chamber adapted to ?t tightly about the covered conductor, a removable die at the rear end of the chamber adapted to ?t loosely about chamber adapted to ?t tightly about the covered the covered conductor, a manhole in the vacuum conductor, a die at the rear end of the chamber chamber approximate the end attached to said adapted to ?t loosely about the covered con extension for facilitating access to the adjacent ductor, and arti?cial cooling means approximate the juncture of said extension and vacuum cham 30 die, and a water jacket operatively surrounding the die at the rear end of the vacuum chamber. ber for-chilling saturant drawn toward the adja cent die by the vacuum within the chamber. JOHN W. OLSON.