Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
  • H01B13/32—Filling or coating with impervious material
  • H01B13/322—Filling or coating with impervious material the material being a liquid, jelly-like or viscous substance
• • 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
• • 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
  • H01B7/2855—Preventing penetration of fluid, e.g. water or humidity, into conductor or cable by completely or partially filling interstices in the cable using foamed plastic

Definitions

• the invention relates to a method for producing a longitudinally sealed electrical and / or optical cable, in particular a communication cable, by filling the cable core with a filling compound which consists of a mixture of a water-repellent, wax-like substance (e.g. petrolatum) with micro-small hollow bodies there is elastic plastic.
• a filling compound which consists of a mixture of a water-repellent, wax-like substance (e.g. petrolatum) with micro-small hollow bodies there is elastic plastic.
• the filling compound called petrolat which has a dielectric constant of about 2.3, increases the operating capacity of cables filled with it by about 20%.
• Particularly good results are achieved with a filling compound made of petrolatum and micro-small hollow bodies, in which the wall of the hollow body is made of an elastic one
• the hollow bodies can be compressed under the influence of greater forces to a volume which is less than half of the original volume and which, when these forces are no longer present, assume their original volume and shape again (DE-PS 31 50 909).
• the spatial extent of individual undeformed hollow bodies is less than 100 pm.
• Hollow bodies of this type are produced by means of special processes from plastics on the basis of polyvinylidene chloride copolymer, the process being carried out in such a way that isobutane as the propellant gas has entered the hollow bodies and the hollow bodies have an average spatial extent (diameter) of 10 pm.
• the foaming process in which the volume of the hollow bodies increases approximately 10 to 100 times, is then carried out with the supply of thermal energy.
• DE-OS 20 21 726 it is also known to mix the petrolatum with non-foamed hollow micro-bodies and to foam the hollow bodies only after the mixing process.
• High-pair cables continue to grow filled with pure petroleum jelly, the viscosity of which can be varied within wide limits due to temperature changes and which, when cooled - i.e. at room temperature - is as tough as wax.
• the pure petrolat liquefied by heating can penetrate well into all cavities of the cable core due to its then low viscosity.
• the viscosity increases sharply with increasing concentration of the filler (hollow body), especially in the case of a high proportion of hollow bodies, the liquefaction of the petrolate component alone means that the viscosity can no longer be brought up to those values which are necessary for the penetration of the filler into the cavities of high-pair souls.
• the invention is therefore based on the object of specifying a method for filling the mass of the type mentioned at the outset, which also allows filling of high-pair cables with this mass.
• a mixed with foamable plastic hollow bodies heated to a temperature below which triggers the foaming of the hollow bodies, water-repellent substance is filled into the cable core and the foaming of the hollow plastic bodies is effected there by supplying additional amounts of heat.
• the water-repellent, wax-like substance will be selected so that it releases propellant gas emerging from the hollow body during the expansion process. This prevents unwanted gas pockets in the filling compound.
• the invention thus conveys to the professional world the teaching that the water-repellent, wax-like substance should not be mixed with already foamed hollow bodies, but instead used hollow bodies which are still foamable and therefore have a much smaller volume than already foamed hollow bodies and are therefore also much easier let it mix with the water-repellent substance.
• a filling compound initially largely retains the physical properties, in particular the viscosity, of the pure substance, because the volume fraction of the expandable hollow bodies in the filling compound can overall remain very low. Similar to the pure substance, this filling compound can be brought into a practically liquid state by increasing the temperature, it being only necessary to note that when this compound is heated, the foaming temperature of the hollow body must not be reached.
• the unexpanded hollow bodies are also mechanically much more resistant than foamed hollow bodies, which is of great importance for the stresses when working, mixing and filling the mass; This is because the hollow bodies are subjected to high mechanical loads, particularly in the pump, especially when the mass is required. Such a high mechanical load also occurs in heat exchangers and during the actual filling process, especially when penetrating the narrow gaps in the cable core.
• the hollow bodies mixed with the water-repellent substance expand only after additional heat has been added.
• the cellular gas content of the filling compound is increased in such a way that at least as low values of the dielectric constant are achieved as in the previously mentioned known filling compounds of low dielectric constant.
• the point in time at which the hollow bodies expand, namely after the filling process has ended, can also be favorably influenced by counteracting the premature expansion tendency with the pressure to be applied during filling.
• the expansion of the hollow bodies within the cable core reliably fills all of their cavities.
• the expansion also leads to a residual pressure in the soul, which is suitable to compensate for any volume shrinkage of the filling compound when it cools down.
• the diameter of the cable core can be fixed by spinning with a holding spiral before adding the additional amount of heat.
• Filling with the new filling compound can also be carried out in such a way that the filling compound formed from the water-repellent substance and foamable hollow bodies is supplied under pressure shortly before filling with heat energy in the amount required to foam all the hollow bodies at atmospheric pressure and so heated mixture while maintaining the pressure in the cable core is filled.
• the supply of the required amount of heat is easier, and it is not necessary to pay strict attention to the fact that the filling temperature of the filling compound is not exceeded before filling.
• the method only presupposes that the storage containers in front of the actual filling system are constructed in such a way that they can also be put under increased pressure.
• the expansion of the hollow body will take place in this case, as in the previously mentioned method, when leaving the filling chamber due to the decrease in pressure caused thereby.
• the cable core will be preheated as a precaution to prevent the filling compound from cooling down when it is filled into the cable core.
• pure petroleum jelly as is usually used for the longitudinal sealing of cables, is mixed with expandable hollow bodies, the wall of which preferably consists of a polyvinylidene chloride-acrylonitrile copolymer, in an amount of 2-5 percent by volume.
• the filling material thus produced is brought to a temperature below the expansion temperature, e.g. B. heated to less than 85 ° C, placed in a practically liquid state and filled in this state with the help of known filling devices, usually under pressure, into the cable core passing through the filling device.
• the cable core can be preheated in a suitable manner immediately before entering the filling device in such a way that the heat energy supplied can cause the temperature of the filling compound to rise above the expansion temperature (for example about 100 ° C.).
• the time of the onset of expansion of the hollow body can be selected by the selected filling pressure of e.g. B. 5 to 15 bar until the thin liquid filling compound with the unexpanded hollow bodies has entered all the cavities of the cable core.
• the heat energy required for the temperature increase can also only after the filling process, for. B. can be supplied by applying RF energy to the filled cable core. It goes without saying that combinations of the possibilities mentioned here are also conceivable.
• the diameter of the cable core will be stabilized by applying a holding helix. With the help of suitable scrapers you will remove the excess mass before further processing the soul and, if necessary, for filling z. B. use low-pair cables.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Insulated Conductors (AREA)
• Manufacturing Of Electric Cables (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6227159

Family Applications (1)

Country Status (3)

Cited By (4)

Families Citing this family (2)

Citations (7)

Family Cites Families (1)

• 1984
  • 1984-02-06 DE DE19843404488 patent/DE3404488A1/de not_active Withdrawn
  • 1984-12-21 DE DE8484730151T patent/DE3464979D1/de not_active Expired
  • 1984-12-21 AT AT84730151T patent/ATE28530T1/de not_active IP Right Cessation
  • 1984-12-21 EP EP84730151A patent/EP0151900B1/fr not_active Expired

Patent Citations (7)

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