US3590141A - Electric cable having improved resistance to moisture - Google Patents

Electric cable having improved resistance to moisture Download PDF

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Publication number
US3590141A
US3590141A US799674A US3590141DA US3590141A US 3590141 A US3590141 A US 3590141A US 799674 A US799674 A US 799674A US 3590141D A US3590141D A US 3590141DA US 3590141 A US3590141 A US 3590141A
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layer
metal shield
cable
conductor
disposed
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Raymond C Mildner
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Dow Chemical Co
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Dow Chemical Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00—Communication cables or conductors
    • H01B11/18—Coaxial cables; Analogous cables having more than one inner conductor within a common outer conductor
    • H01B11/1869—Construction of the layers on the outer side of the outer conductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
    • H01B7/282—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable
    • H01B7/285—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable by completely or partially filling interstices in the cable
    • H01B7/288—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable by completely or partially filling interstices in the cable using hygroscopic material or material swelling in the presence of liquid

Definitions

  • the sheath is disposed within the cable between the protective metal shield and the outer plastic jacket such that the layer of hygroscopic material is in contact with the protective metal shield and the metal shield of the sheath is in contact with the outer plastic jacket.
  • This invention relates to electric cables.
  • this invention relates to electric cables having improved resistance to moisture.
  • this invention relates to coaxial and twisted pair cables wherein the insulating medium between the conductors is protected against the penetration of moisture into the cables.
  • More recent developments in cable construction employ a cylindrical protective metal shield interiorally of the plastic jacket to assist in preventing moisture from permeating into the working parts of the cable.
  • the cylindrical metal shield is formed from a strip of metal folded around the cable core such that the edges overlap to form a' longitudinal seam which is bonded together with an adhesive polymer.
  • the protective metal shield does reduce moisture permeation into the cable, and is probably sufficient in some types of cables such as those designed to transmit signals at low (audio) frequencies the adhesive polymer used to bond the longitudinal seam is not impervious and will permit minute quantities of moisture to pass into the cable where it will collect in the insulation between the conductors.
  • the insulation is of a type sensitive to moisture, such as a foamed plastic material, the presence of these minute quantities of moisture can produce disastrous results.
  • hermetic sheaths such as those fashioned from lead or aluminum can be employed to prevent moisture permeation in place of the pro tective metal shield having the longitudinal seam, this type of protection has many disadvantages in that it is much more expensive, the resulting cable is much heavier, and the cable loses its flexibility.
  • a sheath comprising, in combination, a layer of hygroscopic material disposed around the protective metal shield interiorly of the outer jacket to serve as a sink for absorbing moisture and a metal shield surrounding the layer of hygroscopic material and disposed between the hygroscopic material and the outer jacket.
  • the cable construction of this invention thus has the protective metal shield located as an inner shield relative to the sheath and the outer plastic jacket. Similarily, the metal shield of the sheath is located as an outer shield relative to the inner protective metal shield.
  • the hygroscopic layer and the metal shield surrounding the hygroscopic layer function in combination to prevent moisture from migrating into the working parts of the cable.
  • the metal shield between the hygroscopic layer and the outer jacket is formed by longitudinally folding a metal strip such that the edges thereof are in overlapping relationship to form a longitudinal seam which is bonded together by means of an adhesive polymer.
  • An important requirement of the sheath of this invention is that the metal shield element of the sheath be reasonably resistant to the permeation of moisture to obviate the necessity of having to use a very thick hygroscopic layer which would otherwise be necessary to accommodate large quantities of moisture.
  • the sheath of this invention is thus distinguishable from the concept of employing concentric plastic layers with a layer of moisture absorbent material between them. In the latter construction, the layer of absorbent material would have to be of considerable thickness in order to accommodate the large quantities of moisture which would pass through the outer plastic layer of the concentric plastic layers.
  • Another object of this invention is to provide a layer of hygroscopic material in a cable 'to serve as a sink for absorbing moisture.
  • a further object of this invention is to provide a cable which performs satisfactorily during exposure to moisture.
  • FIG. I is a partial section in isometric view of a cable constructed according to one embodiment ofthe invention.
  • FIG. 2 is a cross section of a cable constructed according to another embodiment of the invention.
  • FIG. 3 is a cross section of a cable constructed according to yet another embodiment of the invention.
  • a cable of the kind with this invention is concerned is one which comprises at least one conductor for transmitting electric signals, insulating means surrounding the conductor, a protective metal shield surrounding the insulating means, and an outer jacket of plastic material.
  • the objects of this invention are realized in the cable described above by the improvement which comprises a sheath comprising, the combination of, a layer of hygroscopic material disposed around the protective metal shield interiorly of the outer jacket to serve as a sink for absorbing moisture and a metal shield surrounding the layer of hygroscopic material and disposed between the layer of hygroscopic material and the outer plastic jacket.
  • the metal shield surrounding the layer of hygroscopic material is fashioned such that the edges thereof lie in overlapping relationship to form a longitudinal seam which is bonded together by means of an adhesive polymer.
  • a layer of plastic material such as a polyolefin or the like is disposed between the protective metal shield surrounding the insulating means and the layer of hygroscopic material.
  • hygroscopic material suitable to serve as a sink for absorbing moisture which migrates'through the outer plastic jacket and which migrates to a much less degree through the longitudinal seam of the metal shield can be used in the practice of the invention.
  • exemplary hygroscopic materials which can be used include paper, cloth, and blends of polymer material and compatible siccative drying agents such as calcium chloride, sodium sulfate, sodium chloride, and the like. Paper is generally preferred as the hygroscopic material because it is generally inert to moisture, relatively inexpensive, and freely available. Further, the paper is quite porous and thus can accommodate the moisture by swelling without imposing dangerous stresses on the cable.
  • Any suitable polymer having a comparatively low modulus which is capable of accommodatinglarge amounts of the siccative drying agent without becoming brittle can be used in the practice of the invention.
  • Exemplary polymer materials which can be blended with the siccative drying agent to form the hygroscopic material includes chlorinated polyethylene, copolymers of ethylene and isobutyl acrylate, and the like. Since a corrosive environment is likely to occur when the siccative drying agent absorbs moisture, a suitable corrosion inhibitor can be admixed with the polymer material and the siccative drying agent if desired.
  • siccative drying agent blended with the Polymer material is largely a matter of personal choice dictated by such factors as economics and the like, it is generally preferred that the drying agent by employed in an amount between about and about 80 weight percent based upon the total weight of the blend.
  • the metal shield surrounding the layer of hygroscopic material which functions in combination with the hygroscopic material to improve the resistance to moisture of the cables constructed in accordance with this invention is fashioned of any suitable metal such as, for example, aluminum, copper, bronze, steel, composites of two or more of the foregoing metals, and the like.
  • the metal shield can be of any suitable and convenient thickness such as, for example, between about 2 and about 20 or more mils.
  • the metal shield be adhesively bonded to the outer jacket by means of an adhesive disposed as a layer over substantially the entire area of contact between the metal shield and the outer jacket.
  • the protective metal shield be bonded to the plastic layer by means of an adhesive disposed as a layer over substantially the entire area of contact between them.
  • the optional layer of plastic material can contain the siccative drying agent and thus serve as the hygroscopic layer if desired.
  • any suitable adhesive can be used to bond the several elements of the cables together.
  • exemplary adhesives include polymers of an olefin such as, for example, ethylene, propylene, and the like, and an ethylenically unsaturated carboxylic acid having between 3 and 8 carbon atoms per molecule such as, for example, acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, isocrotonic acid, tiglic acid, angelic acid, senecioic acid, and the like.
  • Both random and graft copolymers of the olefin and the ethylenically unsaturated carboxylic acid can be used in the practice of the invention.
  • These adhesive copolymers can be obtained commercially or they can be prepared by processes well known in the art. While the invention is not to be bound by any particular technique for preparing the adhesive copolymers, one exemplary technique for producing random copolymers, one exemplary technique for producing random copolymers involves subjecting a mixture of the olefin monomers and acid monomers to a high pressure such as between about 500 and about 1000 atmospheres and to an elevated temperature such as between about 100 and about 400 C. in the presence of a suitable free radical initiator such as ditertiary butyl peroxide.
  • Reaction conditions can be varied to produce random copolymers having the desired molecular weight.
  • Exemplary techniques for producing the graft copolymers which can beused in the practice of this invention are outlined in US. Pat. Nos. 3,177,269 and 3,270,090, the disclosures of which are both specifically incorporated herein by reference.
  • a coaxial cable indicated generally by reference numeral 1 comprises a conductor 2 of copper or the like disposed substantially in the center of the cable and insulating means comprising a plurality of disc-shaped spacers 3 transverse to the conductor 2 and longitudinally spaced thereon.
  • a protective metal shield 4 fashioned of copper, aluminum, or the like and having a longitudinal seam 5 formed by overlapping the edges of a metal strip surrounds the insulating means.
  • protective metal shield 4 serves as a return conductor.
  • a plastic layer 7 of a polyolefin such as polyethylene, polypropylene, or the like surrounds the protective metal shield 4 and is optically bonded thereto by means of an adhesive layer 8 applied to the outer surface of the protective metal shield 4.
  • the plastic layer 7 is an optional feature of the cable construction illustrated in FIG. 1 and the coaxial cable 1 can be fabricated without it if desired.
  • a layer 9 of hygroscopic material fashioned of, for example, paper, textile cloth, blend of polymer material and siccative drying agent, or the like is disposed around the plastic layer 7 and can optionally be bonded thereto by means of an adhesive layer 11 coated on the outer surface of the plastic layer 7.
  • a metal shield 12 surrounds the layer 9 of hygroscopic material and is formed such that the edges thereof lie in overlapping relationship to form a longitudinal seam 13 which is bonded together by means of an adhesive polymer disposed as a bead or the like along the edges of the metal shield.
  • the metal shield 12 is fashioned of any suitable metal such as, for example, aluminum, copper, bronze, steel, composites of two or more of the foregoing metals, or the like.
  • the cable illustrated in FIG. 1 can be fabricated by suitable techniques well known in the art.
  • the disc-shaped spacers 3 are provided with radial slits (not shown) which allow then to be mounted on the conductor 2 as the conductor passes into a cable fabrication apparatus.
  • the protective metal shield 4 surrounding the spacers 3 is formed by longitudinally folding a metal strip and overlapping the edges thereof to provide the longitudinal seam 5 which is bonded together by an adhesive.
  • the optional plastic layer 7 is then extruded over the metal shield 4 by passing the same through a conventional extrusion apparatus.
  • the layer 9 of hygroscopic material is positioned around the plastic layer 7 by any suitable technique depending upon the nature of the hygroscopic material.
  • the hygroscopic material When paper or a textile cloth is employed as the hygroscopic material, it is hellcally wrapped or longitudinally folded over the plastic layer 7.
  • the hygroscopic material comprises a polymer blend and a siccative drying agent it is disposed around the plastic layer 7 by extrusion or the like.
  • the metal shield 12 is disposed around the layer 9 of hygroscopic material by longitudinally folding a metal strip to provide the longitudinal seam 13.
  • the outer plastic jacket 14 is then extruded upon the metal shield 12 by suitable extrusion apparatus.
  • the protective metal shield 4 and the metal shield 12 are provided with adhesive coatings to form a strong bond with their respective adjacent elements in the cable, such adhesive coatings can be applied by extruding the adhesive onto the metal surfaces, depositing the adhesive from solution or a latex, film lamination, or the like.
  • the disc-shaped spacers 3 are illustrated as the insulation means in FIG. 1, it is evident that other forms of insulation can be used such as a helical strip of insulating material or a foamed polyolefin such as foamed polyethylene, foamed polypropylene, or the like.
  • a foamed polyolefin it is preferable applied by passing the conductor 2 through an extruder which extrudes the polyolefin containing a blowing agent under conditions of temperature and pressure to allow the blowing agent toexpand the polyolefin upon leaving the extruder and thereby form a cellular layer.
  • the protective metal shield 4 in the cable structure illustrated in FIG. l is generally fashioned of a material such as copper or the like so that it serves as a conductor for transmitting electric signals.
  • FIG. 2 of the drawings illustrates a cable shown generally by reference numeral 21 comprising two coaxial cables shown generally by reference numerals 22 and 23 which are arranged in a generally parallel relationship.
  • Each of the coaxial cables 22 and 23 comprises a first conductor 24 for transmitting electric signals, insulating means 26 surrounding the first conductor 24, a second or return conductor 27 in a form ofa cylinder positioned around the insulating means 26 with the edges thereof in overlapping relationship to form a longitudinal seam 28 which is preferably bonded together by means of an adhesive, and an outer jacket 29 of plastic material surrounding the conductor 27.
  • Conductor 24 is coaxial cables 22 and 23 is preferably fashioned of copper or the like.
  • the insulation means 26 comprises a foamed polyolefin such as foamed polyethylene or the like.
  • the insulating means can optionally comprise the disc-shaped spacers 3 described in connection with FIG. 1 of the drawings.
  • the return conductor 27 in each of the coaxial cables 22 and 23 is preferably fashioned of a highly conductive material such as copper or the like.
  • the outer plastic jacket 29 in each of the coaxial cables is a suitable polyolefin such as, for example, polyethylene.
  • An optional layer 31 of plastic material which can be either unfoamed or foamed polyethylene or the like is disposed between the coaxial cables 22 and 23 and a layer 9 of hygroscopic material.
  • a metal shield 12 surrounding the layer of hygroscopic material has the edges thereof in overlapping relationship to form a longitudinal seam 13 which is bonded together by means of an adhesive polymer.
  • An outer jacket M of a suitable plastic material such as a polyolefin or the like surrounds the metal shield 12.
  • the several elements of the cable illustrated in FIG. 2 can be bonded together by means of an adhesive copolymer of an olefin and an ethylenically unsaturated carboxylic acid.
  • the return conductor 27 is optionally bonded to the insulation means 26 and the outer jacket 29.
  • the metal shield 12 is optionally adhesively bonded to the outer jacket 14 by means of the adhesive polymer.
  • While the cable 21 of FIG. 2 illustrates two coaxial cables 22 and 23 disposed within the hygroscopic layer 9 and the metal shield 12, it is within the spirit and scope of the invention to employ a plurality of coaxial cables arranged in a generally parallel relationship.
  • the layer 9 of the hygroscopic material, the metal shield 12, and the remaining elements of cable 21 are fabricated of the same materials described in connection with the cable illustrated in FIG. l.
  • Cable 21 is fabricated by employing well known cable forming apparatus including cable shield forming means, cable jacket extruders, and the like.
  • a twisted pair cable shown generally by reference numeral 32 in FIG. 3 comprises a pair of conductor 33 individually insulated with a layer 34 of foamed polyolefin such as polyethylene or the like which are twisted together to form a twisted pair having opposed helical valleys defined by the outer surfaces of the layers 34.
  • a layer 36 of a foamed polyolefin such as polyethylene surrounds the twisted pair and is disposed substantially throughout the helical valleys defined by layers 34 to provide a cylindrical cable core of foamed insulation.
  • A. protective metal shield 37 surrounds the layer 36 and has the edges thereof in overlapping relationship to form a longitudinal seam 33.
  • a layer 39 of solid plastic material such as a polyolefin is disposed between the protective metal shield 37 and a layer 9 of hygroscopic material.
  • the plastic layer 39 is optional and can be omitted from the cable construction illustrated in FIG. 3 is desired.
  • the layer 9 of hygroscopic material is in direct contact with the protective metal shield 37.
  • a metal shield 12 surrounds the layer 9 of hygroscopic material and is generally coextensive therewith.
  • the metal shield 12 is formed with the edges thereofin overlapping relationship to form a longitudinal seam 13 which is bonded together by means of the adhesive copolymer.
  • the metal shield 12 is fashioned of a suitable metal such as, for example, aluminum, copper, bronze, steel, composites of two or more of the foregoing metals, or the like.
  • An outer jacket 14 of plastic material surrounds the metal shield 12 and is fashioned of a suitable polymer material such as polyethylene, poly (vinylchloride), or the like.
  • the layer 9 of hygroscopic material is fashioned from any suitable material such as, for example, those materials described in connection with FIGS. 1 and 2 of the drawings.
  • an adhesive comprising a copolymer of an olefin and an ethylenically unsaturated carboxylic acid disposed as a layer over substantially the entire area of contact between layer 36 of foamed polyolefin and protective metal shield 37 and over substantially the entire area of contact between metal shield 12 and outer jacket 14.
  • the cable design illustrated by FIG. 3 is a twisted pair cable, it is within the spirit and scope of the invention to employ any number of twisted pairs or twisted quads.
  • the protective metal shield and the metal shield surrounding the layer of hygroscopic material it is generally preferred that some free space be provided between the protective metal shield and the metal shield surrounding the layer of hygroscopic material to allow the hygroscopic material to expand as an incident to the absorption of water.
  • paper in and of itself normally contains enough free space to accommodate this expansion.
  • the hygroscopic layer is fashioned of a blend of a polymer material and a siccative drying agent, the polymer material can be partially or completely foamed if desired.
  • longitudinal passages in the vicinity of the hygroscopic layer should be avoided to prevent longitudinal movement ofthe moisture.
  • the metal shield of the sheath can be constructed of any suitable metal, it is generally preferred to employ tin plated steel because of the better electromagnetic shielding which this material provides at low frequencies and because it is mechanically stronger than the softer metals such as copper or aluminum, so that it affords better mechanical protection to the cable.
  • Example illustrates the improved results obtained with the cable sheath of this invention. It must be understood that this Example is for illustration purposes only and should not be construed as limiting of the invention.
  • An air-spaced coaxial cable having an insulated center conductor, a return conductor, and a layer ofpolyethylene in the form of an inner jacket surrounding the return conductor is provided with a sheath comprising a layer of hygroscopic paper 20 mils thick and a metal shield surrounding the hygroscopic paper layer.
  • the metal shield is formed by longitudinally folding an 8-mil thick strip of aluminum around the layer of hygroscopic paper such that the edges of the strip overlap to form a longitudinal seam.
  • the strip of aluminum which forms the metal shield has a 2-mil thick coating of an adhesive copolymer of ethylene and acrylic acid on the surface of the strip which becomes the exterior surface of the metal shield.
  • the adhesive copolymer bonds the edges of the metal shield along the longitudinal seam and also bonds the metal shield to an outer jacket of polyethylene which is then extruded over the shield.
  • Table 1 The several elements of the cable are set forth in Table 1 below.
  • the permeability (P) of low density polyethylene is taken as l l cc. at standard temperature and pressure per centimeter per second per cm. of Hg. at C.
  • the calculations also employ an upper limit 50 percent relative humidity in the air space between the conductors. This upper limit may be accepted as the maximum tolerable relative humidity to avoid condensation within the air space when the temperature of the cable decreases.
  • the flow of moisture, F, through a layer of polyethylene in a cable, such as through the inner jacket or the outer jacket, is governed by the expression where: F cc of water/day/cm. of cable length P permeability of the polyethylene A p pressure differential across the polyethylene layer D Outer diameter of the polyethylene layer D inner diameter of the polyethylene layer in the several runs, the cable is immersed in water to provide an ambient relative humidity of 100 percent.
  • the flow of moisture (F) into a coaxial cable comprising only Elements 1, 2 and 3 of Table 1, except that the longitudinal seam of the return conductor is not bonded nor is the return conductor bonded to the inner jacket (i.e., the return conductor does not have an adhesive copolymer coating), is determined by the formula above to be 2.4 cc. per day per cm. of cable length. This corresponds to about 40 micrograms per day per'cm. of cable length.
  • the volume of air between the conductors is about 2 cubic centimeters per centimeter length of cable. Since the density of saturated water vapor is 17.3 micrograms /cc. at 20 C., the air space between the conductors would have a relative humidity of percent in less than one day for a water vapor flow of 40 micrograms per day. Control No. 2
  • a coaxial cable is made from elements 1, 2, 3, 5, and 6 only of Table 1 except no adhesive copolymer is employed in the construction (i.e., the same cable construction as outlined in control No. 1 except in this run the cable is provided also with an unbonded rnetal shield and an outer jacket).
  • the additional metal shield and outer jacket would serve to reduce moisture penetration by one-half.
  • the air space between the conductors in this construction would achieve about 100 percent relative humidity in about 2 days.
  • a coaxial cable is made from the elements in control 3 except the longitudinal seams in the return conductor and in the metal shield are bonded with adhesive copolymer.
  • the return conductor and metal shield are also adhesively bonded to their respective polyethylene elements.
  • the additional metal shield and outer jacket serves to reduce the penetration of moisture over the cable construction of Control No. 3 by one-half.
  • the air in the air space of this cable construction will reach a relative humidity of 50 percent in about days.
  • a cable constructed according to the invention and employing all of the elements identified in Table l utilizes a hygroscopic paper weighing about 0.3 grams per cm. of cable length.
  • the paper is of a type which will absorb water vapor equal to about 7.5 weight percent of its own weight when in equilibrium with air having a relative humidity of 50 percent or about 15 weight percent when in equilibrium with air havi-ng a relative humidity of 100 percent.
  • a sheath comprising, in combination:
  • a metal shield surrounding said layer of hygroscopic material and disposed between said layer of hygroscopic material and said outer jacket, said metal shield having the edges thereof in overlapping relationship to form a longitudinal seam bonded together by means of an adhesive polymer.
  • a cable according to claim 1 wherein said layer of hygroscopic material is fashioned of a material selected from the group consisting of paper, cloth, blends of polymer material and calcium chloride, blends of polymer material and sodium sulfate and blends of polymer material and sodium chloride.
  • a cable according to claim 1 wherein said metal shield surrounding said layer of hygroscopic material is fashioned of a metal selected from the group consisting of aluminum, copper, bronze, steel, and composites of two or more of the foregoing metals.
  • a cable according to claim 1 wherein said conductor is a single conductor of copper disposed substantially in the center of said cable, said insulating means comprises a plurality of disc-shaped spacers transversely positioned on said conductor and longitudinally spaced thereon, and said protective metal shield comprises a conductor fashioned of a material selected from the group consisting of copper and aluminum.
  • a cable according to claim 1 which includes a layer of plastic material disposed between said protective metal shield and said layer of hygroscopic material.
  • each of said coaxial cables comprising;
  • a second conductor in the form of a cylinder positioned around said insulating means characterized by having a longitudinal seam formed by overlapping the edges of a metal strip used to form said second conductor
  • a sheath comprising, in combination:
  • a metal shield surrounding said layer of hygroscopic material and disposed between said layer of hygroscopic material and said outer jacket, said metal shield having the edges thereof in overlapping relationship to form a longitudinal seam bonded together by means of an adhesive.
  • a cable according to claim 10 which includes a layer of plastic material disposed between said plurality of coaxial cables and said layer of hygroscopic material.
  • said second conductor in each of said coaxial cables is fashioned of a metal selected from the group consisting of aluminum and copper, and
  • said metal shield surrounding said layer of hygroscopic material is fashioned of a metal selected from the group consisting of aluminum, copper, bronze, steel, and composites of two or more of the foregoing metals.
  • a cable according to claim 10 wherein said layer of hygroscopic material is fashioned of a material selected from the group consisting of paper, cloth, blends of polymer material and calcium chloride, blends of polymer material and sodium sulfate, and blends of polymer material and sodium chloride.
  • a twisted pair cable comprising a pair of conductors individually insulated with a layer of foamed polyolefin and twisted together to form a twisted pair having opposed helical valleys defined by the outer surfaces of said layers of foamed polyolefin, a layer of foamed polyolefin surrounding said twisted pair and disposed substantially throughout the helical valleys therein, a protective metal shield surrounding said layer of foamed polyolefin and characterized by having a longitudinal seam formed by overlapping the edges of a metal strip used to form said protective metal shield, and an outer the improvement comprising a sheath comprising, in combination:
  • a metal shield surrounding said layer of hygroscopic material and disposed between said layer of hygroscopic material and said outer jacket, said metal shield having the edges thereof in overlapping relationship to form a longitudinal seam bonded together by means of an adhesive.
  • a twisted pair cable according to claim 15 which includes a layer of plastic material disposed between said protective metal shield and said layer of hygroscopic material.

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US (1) US3590141A (enrdf_load_stackoverflow)
BE (1) BE746016A (enrdf_load_stackoverflow)
DE (1) DE2005881B2 (enrdf_load_stackoverflow)
FR (1) FR2031461B1 (enrdf_load_stackoverflow)
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US3766309A (en) * 1970-07-14 1973-10-16 P Calzolari Electric cable with corrugated metallic sheath
US3935374A (en) * 1971-12-18 1976-01-27 Sumitomo Electric Industries, Ltd. Laminated sheathed cable
DE2754336A1 (de) * 1977-12-02 1979-06-07 Aeg Telefunken Kabelwerke Hochspannungskabel mit kunststoffisolierung
WO1980000895A1 (en) * 1978-10-27 1980-05-01 Nordiske Kabel Traad Power cable and method for the manufacturing of such cables
US4372043A (en) * 1980-11-14 1983-02-08 Westinghouse Electric Corp. Method of assembling a gas-insulated power transmission line with duter enclosure of carbon steel and aluminum
US6246006B1 (en) 1998-05-01 2001-06-12 Commscope Properties, Llc Shielded cable and method of making same
US6384337B1 (en) 2000-06-23 2002-05-07 Commscope Properties, Llc Shielded coaxial cable and method of making same
US6683256B2 (en) * 2002-03-27 2004-01-27 Ta-San Kao Structure of signal transmission line
US20070051450A1 (en) * 2003-07-25 2007-03-08 Fabrizio Donazzi Continuous process for manufacturing electrical cables
WO2011078865A1 (en) 2009-12-23 2011-06-30 Paul Cinquemani Flexible electrical cable with resistance to external chemical agents
US9459371B1 (en) * 2014-04-17 2016-10-04 Multi-Shot, Llc Retrievable downhole cable antenna for an electromagnetic system
US10385683B1 (en) 2018-02-02 2019-08-20 Nabors Drilling Technologies Usa, Inc. Deepset receiver for drilling application
EP3432318A4 (en) * 2016-09-22 2020-02-26 Yamagishi, Hiromitsu CABLE, DEVICE AND METHOD FOR POWER SUPPLY
US10726974B1 (en) * 2019-12-13 2020-07-28 American Fire Wire, Inc. Fire resistant coaxial cable for distributed antenna systems
US10760412B2 (en) 2018-04-10 2020-09-01 Nabors Drilling Technologies Usa, Inc. Drilling communication system with Wi-Fi wet connect
US11145440B2 (en) 2016-12-20 2021-10-12 American Fire Wire, Inc. Method of testing a fire resistant coaxial cable
CN116359598A (zh) * 2023-03-16 2023-06-30 华电(烟台)功率半导体技术研究院有限公司 一种耐高压高温高湿大电流采集系统
US11942233B2 (en) 2020-02-10 2024-03-26 American Fire Wire, Inc. Fire resistant corrugated coaxial cable

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DE2522000C2 (de) * 1975-05-15 1976-10-07 Siemens Ag Koaxiales hochfrequenzkabel
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US3766309A (en) * 1970-07-14 1973-10-16 P Calzolari Electric cable with corrugated metallic sheath
US3935374A (en) * 1971-12-18 1976-01-27 Sumitomo Electric Industries, Ltd. Laminated sheathed cable
DE2754336A1 (de) * 1977-12-02 1979-06-07 Aeg Telefunken Kabelwerke Hochspannungskabel mit kunststoffisolierung
WO1980000895A1 (en) * 1978-10-27 1980-05-01 Nordiske Kabel Traad Power cable and method for the manufacturing of such cables
US4372043A (en) * 1980-11-14 1983-02-08 Westinghouse Electric Corp. Method of assembling a gas-insulated power transmission line with duter enclosure of carbon steel and aluminum
US6246006B1 (en) 1998-05-01 2001-06-12 Commscope Properties, Llc Shielded cable and method of making same
US6384337B1 (en) 2000-06-23 2002-05-07 Commscope Properties, Llc Shielded coaxial cable and method of making same
US6683256B2 (en) * 2002-03-27 2004-01-27 Ta-San Kao Structure of signal transmission line
US20070051450A1 (en) * 2003-07-25 2007-03-08 Fabrizio Donazzi Continuous process for manufacturing electrical cables
AU2009356974B2 (en) * 2009-12-23 2015-02-05 Prysmian S.P.A. Flexible electrical cable with resistance to external chemical agents
WO2011078865A1 (en) 2009-12-23 2011-06-30 Paul Cinquemani Flexible electrical cable with resistance to external chemical agents
US9424962B2 (en) 2009-12-23 2016-08-23 Prysmian S.P.A. Flexible electrical cable with resistance to external chemical agents
US9459371B1 (en) * 2014-04-17 2016-10-04 Multi-Shot, Llc Retrievable downhole cable antenna for an electromagnetic system
EP3432318A4 (en) * 2016-09-22 2020-02-26 Yamagishi, Hiromitsu CABLE, DEVICE AND METHOD FOR POWER SUPPLY
US10600534B2 (en) * 2016-09-22 2020-03-24 Hiromitsu YAMAGISHI Cable, device and method of supplying power
US11145440B2 (en) 2016-12-20 2021-10-12 American Fire Wire, Inc. Method of testing a fire resistant coaxial cable
US10385683B1 (en) 2018-02-02 2019-08-20 Nabors Drilling Technologies Usa, Inc. Deepset receiver for drilling application
US10760412B2 (en) 2018-04-10 2020-09-01 Nabors Drilling Technologies Usa, Inc. Drilling communication system with Wi-Fi wet connect
US10726974B1 (en) * 2019-12-13 2020-07-28 American Fire Wire, Inc. Fire resistant coaxial cable for distributed antenna systems
US11881329B2 (en) 2019-12-13 2024-01-23 American Fire Wire, Inc. Method of manufacturing fire resistant coaxial cable for distributed antenna systems
US11942233B2 (en) 2020-02-10 2024-03-26 American Fire Wire, Inc. Fire resistant corrugated coaxial cable
CN116359598A (zh) * 2023-03-16 2023-06-30 华电(烟台)功率半导体技术研究院有限公司 一种耐高压高温高湿大电流采集系统

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Publication number Publication date
DE2005881A1 (de) 1970-08-27
DE2005881B2 (de) 1978-09-07
FR2031461B1 (enrdf_load_stackoverflow) 1974-09-06
GB1258221A (enrdf_load_stackoverflow) 1971-12-22
NL7001311A (enrdf_load_stackoverflow) 1970-08-19
BE746016A (fr) 1970-08-17
FR2031461A1 (enrdf_load_stackoverflow) 1970-11-20

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