Патент USA US2112322код для вставки
March -29, 1938. K. s. wYA’TT 2,112,322 CABLE Filed Jan. 18, 1935 19 TEE/771757 Nif/7071279 2 \ Z , l 625 @M0706 for L15-2 24 ¿27g/EW DF mig? cw. n Patented Mar. 29, 1938 2,112,322 ~ ` UNITED STATES PATENT OFFICE 2,112,322 CABLE Kenneth S.'Wyatt, Detroit, Mich., assignor to The Detroit Edison Company, Detroit, Mich., a corporation of New York Application January 18, 1935, Serial No. 2,328 14 Claims. This invention relates to the insulation of elec l tric cables so‘that they are able to withstand . Kthe tremendous electrical stresses created during ` the use of the cable. More speciñcally this invention relates to the insulation of cables for electric current trans mission having one or more centrally arranged conductors enclosed in a lead sheath and having (Cl. 173-264) these products seems to be their ability to carry current, which, of course, increases the dielectric loss in the cable. Some of these products are un doubtedly deterioration or oxidation products and all of them impair the electrical characteristics 5 to some extent, particularly when they collect in large quantities. Although voids in cable insulation, occurring as insulating material surrounding the conductors . a result of expansion followed by unequal con 10 rendered active for the adsorption of such harm traction tend to facilitate the collection of large 10 ful products a`s maybe formed during the use masses of deterioration products, it is possible` of the cable or which may be present therein under some circumstances that any ionized mole when the cable is manufactured. cules present could collect in the vapor state Cables of the type above referred to are gen within the insulation, to form a gas pocket. 15 erally formed by wrapping one or more electric - current conductors with an insulating impreg 'natedmateriaL oils and various types of fibrous 9 materials such as paper tape being used for this purpose. The'tape is wound around the conduc tors to provide a pluralityof conductor insulat » inglayers, and one or more conductors, which may becoated with a metal shielding tape, are surrounded with a packing material such as jute. cellulose fiber, etc., the packed conductors then 25 being sheathed Within the customary lead cover ing in the well known manner. If desired an additional insulating belting may be wrapped around the jute or cellulose fiber packing and the so wrapped mass covered with the lead 30 sheath. In my copending application Serial No. 693,697, ñled October 16,-1933, which has matured to Patent 2,083,889 dated June 15, 1937 and en titled “Oxidation resistant cable” I have de 35 scribed how the harmful effects of oxidation of the insulating material can be prevented by the incorporation of anti-oxidants into the inner and outer windings of the insulation. It now appears that other products may have 40 Aa deleterious effect on cable operation, some of Other deterioration products, forming perhaps 15 around any catalyzer which may be present, also collect in relatively large continuous bodies. I propose to reduce the harmful effect of the several deterioration products by locating Within the insulating material agents adapted actively 20 to adsorb these products, and by preventing the collection of large bodies of these lharmful prod ucts, it is possible to minimize the amount of current which they carry and thus reduce their harmful effect on the insulating material. 25 These adsorbing agents, designed to adsorb the various harmful or deterioration products pres ent in the cable, may b_e used in'conjunction with theanti-oxidant material disclosed in my above referred to application, or they may be used by themselves, depending upon the type of product, which under various conditions, appears to be most harmful. _ The use of agents of this nature will permit the use of a poorer grade of paper or oil under certain circumstances, the cable insulation then undergoing what may be called a refining action in place. _ It is therefore an object of this invention to provide an electric cable with insulating material 40 these products perhaps being present in the cable 'which is protected against the inñuence of de as originally manufactured, and some products terioration products present in the cable. undoubtedly representing combinations of some A further object of this invention is to make of the original materials present, some of these l 45 combinations probably being formed as a result ofthe conditions .caused by operation of the cable. Among these harmful products may be listed moisture, hydrogen, carbon dioxide, carbon 50 monoxide, sulphur compounds, nitrogenous com pounds, hydro-carbon acids such as the substi tuted acetylencs, dispersed cellulose particles carrying electric charges, metal soaps, and ions of these or other substances formed by the 55 several forces present. 'I'he harmful effect of use of the adsorptive properties of certain ma terials for reducing the harmful effect due to 45 ionization of the insulating materials used in electric cables. A further object of this invention is to reduce the impairment of the insulating properties of cable insulating materials by dispersing active 50 adsorbing agents throughout said materials. Other and further objects of this invention will be apparent from the following detail descrip~ tion of the accompanying sheet of drawings which forms a part of this specification. - 55 2 2,112,322 ing use of the cable, or that are present originally. On the drawing: Figure 1 is a sectional view of a three-con ductor belted cable having paper insulation tape wound around the conductors with adsorbing agents dispersed between the layers of the wound tape, and with anti-oxidant material impregnated into the inner and outer windings of said tape. Figure 2 is a vertical cross-sectional view of a three-conductor H-type cable having oil im pregnated paper tape surrounding each conductor with adsorbing agents dispersed between the windings of the tape, and with anti-oxidant ma terial impregnated into the inner and outer wind ings of said tape. i ` Figure 3 is a vertical cross-sectional view of one of the insulated conductors shown in Figure l having oil impregnated paper tape wound there around with an adsorbing agent dispersed be tween the inner and outer layers only of the in sulation windings. Figure 4 is a vertical cross-sectional view of one of the conductors shown in Figure 1 having oil impregnated insulation paper tape wound there around with an adsorbing agent dispersed between each of the layers of tape. As shown on the drawing: ' In Figure l, the reference numerals Il, I I, and I2 indicate respectively the three sets of wires forming the three cable conductors. Each con ductor III, II, and I2 is surrounded with a cov ering of mineral oil impregnated paper tape I4 wound therearound. The ürst few inner wind ings IB of the paper tape I4 are treated with an anti-oxidant material such _ as hydroquinone, camphor or the like, in accordance with the in vention disclosed in my application Serial No. 693,697. 'I'he last few outer windings I6 are sim ilarly treated with anti-oxidant material. In accordance with this invention an active ad 40 sorbing agent such as activated charcoal, de hydrated silicic acid (silica gel), dehydrated fer- - ric hydroxide gel, exploded cellulose übers or sim~ ilar material I1 capable of adsorbing ions is dis persed between the windings of the paper tape I4. This adsorbing agent is readily applied, in dry comminuted form, to the oil impregnated in sulation tape by dusting the adsorbing agent over the oil soaked tape. The oil ülm on the tape acts as an adhesive and retains a sufiicient amount of 50 adsorbing agent thereon. Alternatively the übrous insulating tape itself may be made, in a dry atmosphere, of exploded cellulose fibre or other similar material capable of adsorbing ions and other deterioration prod 55 ucts. Instead of dusting the adsorbing agent over the tape, the agent may be mechanically entan gled in the über of the paper itself, this process also being carried on in the absence of moisture, the tape thereafter being immediately wound on 60 the conductor in order to minimize the adsorption of moisture by the agents. A üller material I8 such as jute or cellulose fiber is packed around the outside of the paper tape I4 and the entire mass is wrapped in an insulation 05 belting I9. A lead sheath 20 forms the outside of the cable and surrounds the insulation belting I9. . The cable disclosed in Figure 1 is thus composed of three conductors for electric current having 70 paper tape insulation to separate the conductors. The insulation is impregnated in the inner and outer windings with anti-oxidant material and an y adsorbing agent is dispersed between the wind ings of the tape to actively adsorb any ions or other deterioration products that are formed dur In Figure 2, the reference numerals 2i, 22, and 23 indicate respectively the wires forming the three conductors of an H-type cable. Each con ductor 2l, 22, and 23 is surrounded by an insula tion covering comprising a plurality of layers of oil impregnated insulation paper 24. The inner windings 25 of the insulation paper are treated with anti-oxidant material to minimize the harm ful eü'ects of oxidation of the paper or of the oil. Likewise the outer windings 2l are also im pregnated with an anti-oxidant material. In ac-V cordance with this invention materials capable of adsorbing deterioration products, such as ions etc., are dispersed between the windings of the paper insulation 24 as shown at 21. A copper shielding tape 2l is then wound around the paper insulations in each conductor and the three conductors are packed together in a lead sheathing 29. Filler material such as cellulose 20 fibers 3|! are provided to üll up the spaces between the insulated conductor and the outside lead sheath. The cable disclosed in Figure 2 is thus composed of three conductors having windings of paper in 25 sulation separating the same from each other. Anti-oxidant material is impregnated into the, in ner and outer insulation windings of each con ductor and an agent capable of adsorbing ions is dispersed between the windings of each paper in 30 sulation. A shielding tape then surrounds the windings of each conductor and the three conduc tors are packed together in a lead sheath. In Figure 3 the conductor 33 has wrapped there around a plurality of windings of paper insulation ~ 34. The ürst few inner windings li have dispersed therebetween an ion adsorbing material or agent 31 such as is described above. Likewise the last few windings 36 have the ion adsorbing material 31 dispersed therebetween. ’I'he insulation 24 40 thus has the adsorbing agent dispersed between the inner and outer windings only, since the ioni zation occurs more at these positions. In Figure 4 the reference numeral 4B indicates a conductor for electrical current having insula tion paper 4I wrapped therearound. Adsorbing material such as activated charcoal, hydrated silicio acid or exploded cellulose übers 42 are dis persed between the layers of the paper insulation 4I. These materials can be used alone or to gether in any manner required by the type of im 50 purities present. , From the above description of the drawing it is evident that cables can be prepared according to this invention with insulation tape wound around the conductors and having adsorbing agents irn- ' pregnated between some or all of the layers of the tape. In addition speciüc anti-oxidant mate rial can be incorporated or impregnated into the inner and outer windings of the insulaton tape as shown in Figures 1 and 2. . 60 These adsorbing agents as a class have extended surfaces capable of holding, by surface attraction, the ions and other particles of deterioration prod ucts. Substances having a high adsorptive ability coupled with a low power factor such as activated 65 charcoal, dehydrated silicio acid and dehydrated _ ferrie hydroxide, are suitable adsorbing agents for these materials. I also propose to use freshly exploded paper. pulp, or _textile übers. These materials are exploded in much the same manner as cereal grains are exploded to form the weli known puffed cereals. In other words the textile übers or pulp are-subjected to high steam pres sure and then shot into the atmosphere where they burst or expand and develop extended sur 3 2,112,322 faces. Other means, well known in the art for separating the micelles may also be used. The extended surfaces of these fibrous portions are capable of adsorbing ions and the other deteriora tion products mentioned above. By dlspersing the adsorbing agents between the layers of the insulation tape it is possible to ad sorb the ions in the layers of adsorbing agents as they are formed and prevent their accumulation in any given spot as might otherwise occur, such accumulation of the :fons Gauting breakdown of the cable insulation. When adsorbing agents are used with insulating paper or oil material which is rich in harmful 15 products, the agents will, by removing them from the ñber of the paper or from the oil, tend further to reñne the insulating material so that such ma terial can, in spite of impurities present in the original cable, yet give adequate service in oper 20 ation. Since the electrical stresses are greatest at the conductor and again in the vicinity of the sheath, ions in the liquid and solid phase occur in great est numbers at these points and consequently it 25 is desirable in some circumstances to concentrate ion adsorbing materials at these points. Ions in the gas phase, however, are formed in that zone of the cable insulation which, after operation, contains the most voids. Since the location of the 30 voids varies with the type and manufacture of the cable, although usually it occurs in the inner third of the insulation, adsorbers for ions in the vapor phase will be located in accordance with the requirements of the individual cable. y35 thereof. 5. In an insulated cable having a plurality of conductors for electric‘ current, oil impregnated insulation tape wound around said conductors, a non-conductor ion adsorbing agent dispersed be tween the layers of said insulation tape and a covering for said cable. 6. A cable comprising a plurality of conductorsfor electrical current, oil impregnated paper wound around each of said conductors, a non conductor ion adsorbing agent dispersed between the inner windings and between the outer wind ings of said tape, and means for covering the so insulated conductors. 7. A cable comprising a plurality of conductors for electrical current, insulating material wound around each of said conductors, activated char coal dispersed between the layers of said insulat ing material and a sheath for the so insulated conductors. 8. A cable comprising a, plurality of conductors for electrical current, insulation material wound around each of said conductors, dehydrated silicic acid dispersed between the layers of said insula 25 tion material and means for sheathing the so in sulated conductors. 9. A cable comprising a plurality of conductors for electric current, insulating material wound around each of said conductors, exploded ñbrous 30 material dispersed between the layers of said in sulation material and means for sheathing the so insulated conductors. I am aware that numerous details of the proc 10. A cable for transmitting electric current comprising three conductors, oil impregnated pa ess and apparatus may be varied through a wide per tape wound around each of said conductors range without departing from the principles of this invention, and I, therefore, do not propose limiting the patent granted hereon otherwise than .40 necessitated by the prior art. I claim as my invention: 1. A cable comprising conductors, insulation wound around each conductor and a non-con ductor ion adsorbing agent dispersed between the 45 windings of said insulation. 2. A cable comprising a conductor for electric current, insulating means wound around said con ductor and a non-conductor ion adsorbing agent dispersed between the windings of said insulating 50 adsorbing agent dispersed between the windings means. t 3. An electrical cable comprising an electrical conductor, layers of insulating material surround ing said conductor, a non-conductor ion adsorb ing agent dispersed between the layers of insu lating material and an outside covering for said cable. 4. In an insulated electrical cable, oil impreg nated paper tape insulation wound around the current conductors having a non-conductor ion to form a plurality of layers therearound, a non conductor ion adsorbing agent dispersed between said layers, a filler surrounding the insulation material and a lead sheathing enclosing the in sulated conduits. ll. A cable having a conductor for electric cur rent and a non-conductor ion adsorbing insulat ing means surrounding said conductor. l2. A cable comprising a conductor, insulating 45 material surrounding the conductor, and non conducting ion adsorbing insulation refining ma terial dispersed between adjacent portions of said insulating material, said refining material being insoluble in said insulating material. 50 13. The process of refining the insulating ma terial of a cable which includes the step of re fining said material after the assembly of said cable with a non-conducting ion adsorbing agent. 14. In an electrical cable having a plurality of 55 conductors, oil impregnated insulation tape wound around each of said conductors, and ac tivated charcoal disposed between the layers of said tape. KENNETH S. WYA'I'I’.