DEP0052630DA - Spraying process for sheathing electrical cables with thermoplastic insulating materials - Google Patents
Spraying process for sheathing electrical cables with thermoplastic insulating materialsInfo
- Publication number
- DEP0052630DA DEP0052630DA DEP0052630DA DE P0052630D A DEP0052630D A DE P0052630DA DE P0052630D A DEP0052630D A DE P0052630DA
- Authority
- DE
- Germany
- Prior art keywords
- insulating materials
- thermoplastic insulating
- spraying process
- electrical cables
- spray head
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011810 insulating material Substances 0.000 title claims description 8
- 238000000034 method Methods 0.000 title claims description 5
- 229920001169 thermoplastic Polymers 0.000 title claims description 4
- 239000004416 thermosoftening plastic Substances 0.000 title claims description 4
- 238000005507 spraying Methods 0.000 title description 3
- 239000004020 conductor Substances 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- 239000007921 spray Substances 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 230000008878 coupling Effects 0.000 claims description 2
- 238000010168 coupling process Methods 0.000 claims description 2
- 238000005859 coupling reaction Methods 0.000 claims description 2
- 238000002347 injection Methods 0.000 claims description 2
- 239000007924 injection Substances 0.000 claims description 2
- 239000004033 plastic Substances 0.000 claims 1
- 229920003023 plastic Polymers 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
Description
Bei der Herstellung von Ummantelungen von elektrischen Leitungen oder dergleichen mit thermoplastischen Isolierstoffen, insbesondere bei solchen mit hohem Wärmeausdehnungskoeffizienten, wurde beobachtet, daß nach Abkühlung des Isoliermaterials sich dieses vom Leiter unter Bildung von blasenförmigen Hohlräumen auf der Leiteroberfläche abgehoben hatte. Diese Hohlräume führten bei Spannungsbeanspruchungen zu erhöhten Verlusten, indem eine Isolierung stattfand, die schließlich zu einem Wärmedurchschlag führte. Diese Hohlräume entstehen dadurch, daß der thermoplastische Isolierstoff, insbesondere durch seinen hohen Wärmeausdehnungskoeffizienten beim Durchlaufen des Wasserbades nach dem Spritzen zunächst in der Außenschicht abgekühlt und fest wird. Die noch warmen inneren Schichten ziehen sich infolge der Abkühlung zusammen und lösen sich vom Innenleiter ab, da die äußeren, schon festen Schichten des Isoliermaterials nicht mehr nachgeben.In the production of sheaths for electrical lines or the like with thermoplastic insulating materials, especially those with a high coefficient of thermal expansion, it was observed that after the insulating material had cooled, it had lifted off the conductor with the formation of bubble-shaped cavities on the conductor surface. These cavities led to increased losses when stressed, in that insulation took place, which ultimately led to heat breakdown. These cavities arise from the fact that the thermoplastic insulating material, in particular due to its high coefficient of thermal expansion, is initially cooled and solidified in the outer layer when it passes through the water bath after spraying. The still warm inner layers contract as a result of the cooling and detach from the inner conductor, since the outer, already solid layers of the insulating material no longer yield.
Gemäß der Erfindung wird dieser Nachteil dadurch beseitigt, daß die aus dem Spritzkopf austretende Leitung unter Druck abgekühlt wird. Um dies zu erreichen, wird zweckmäßig unmittelbar an den Spritzkopf ein insbesondere mit Wasser gefülltes Kühlrohr angeschlossen, das unter einem Überdruck von einigen, insbes. 5 atü steht. Zweckmäßig wird das Kühlrohr mit dem Spritzenkopf durch ein teleskopartiges Rohr mit Kupplungsflansch verbunden. Durch den von außen wirkenden Druck wird das noch teigförmige Isoliermaterial auf dem Leiter verdichtet, und es kann einen Hohlraumbildung infolge Schrumpfens durch die Verdichtung nicht mehr stattfinden.According to the invention, this disadvantage is eliminated in that the line emerging from the spray head is cooled under pressure. In order to achieve this, a cooling pipe, which is filled with water and is under an overpressure of a few, in particular 5, atmospheres, is expediently connected directly to the spray head. The cooling tube is expediently connected to the syringe head by a telescopic tube with a coupling flange. The pressure exerted from the outside compresses the insulation material, which is still in the form of a dough, on the conductor, and the formation of cavities as a result of shrinkage as a result of the compression can no longer take place.
Bei einer beginnenden Schrumpfung des Isolierstoffes sofort nach Austritt aus dem Mundstück der Spritze kann die eventuell beginnende Hohlraumbildung zusätzlich noch mit aus der Spritzmasse nachfließendem Isoliermaterial ausgeglichen werden.If the insulating material begins to shrink immediately after it emerges from the mouthpiece of the syringe, any cavity formation that may begin can also be compensated for with insulating material flowing in from the injection compound.
Das erfindungsgemäße Verfahren ist bei allen thermoplastischen Materialien, insbesondere bei solchen mit hohem Wärmeausdehnungskoeffizienten, anwendbar.The method according to the invention can be used with all thermoplastic materials, in particular with those with a high coefficient of thermal expansion.
In der Zeichnung ist eine Vorrichtung zur Ausübung des erfindungsgemäßen Verfahrens schematisch dargestellt. An die Spritzmaschine (1) mit dem Mundstück (2) ist mittels eines Flansches (3) ein Zählrohr (4) angeschlossen, in welchem sich das Wasser befindet, das unter einem Druck von beispielsweise 5 atü steht und auf die ummantelte Leitung (5) einwirkt.In the drawing, a device for performing the method according to the invention is shown schematically. A counter tube (4) is connected to the spraying machine (1) with the mouthpiece (2) by means of a flange (3), in which the water is located, which is under a pressure of, for example, 5 atmospheres and is transferred to the jacketed line (5) acts.
Claims (3)
Family
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