DK142268B - Method of continuous manufacture of heat insulated conduit. - Google Patents

Method of continuous manufacture of heat insulated conduit. Download PDF

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Publication number
DK142268B
DK142268B DK253975A DK253975A DK142268B DK 142268 B DK142268 B DK 142268B DK 253975 A DK253975 A DK 253975A DK 253975 A DK253975 A DK 253975A DK 142268 B DK142268 B DK 142268B
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Denmark
Prior art keywords
plastic
foaming
continuous manufacture
foam
tube
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DK253975A
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Danish (da)
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DK142268C (en
DK253975A (en
Inventor
Gerhard Ziemek
Bernd Eilhardt
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Kabel Metallwerke Ghh
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Priority to DK253975A priority Critical patent/DK142268B/en
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Publication of DK142268B publication Critical patent/DK142268B/en
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Description

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Vp.a/ (11) FREMLÆGGELSESSKRIFT 142268 DANMARK <«>lm.CI.* B 29 O 27/00 • (21) Ansøgning nr. 2539/75 (22) Indleveret den 4. jun. 1975 (24) Løbedag 4. juTl. 1975 (44) Ansøgningen fremlagt og ^ fremlaggeteesskriftet offentliggjort den 5 · Okt. 1 98ΟVp.a / (11) PUBLICATION 142268 DENMARK <«> lm.CI. * B 29 O 27/00 • (21) Application No. 2539/75 (22) Filed on 4 June. 1975 (24) Race day 4 juTl. 1975 (44) The application submitted and the publication paper published on 5 · Oct. 1 98Ο

DIREKTORATET FORDIRECTORATE OF

PATENT-OG VAREMÆRKEVÆSENET (3°) Prioritet begæret fra den (71) KABEL- UND METALIWERKE GUTEHOFFNUNGSHUETTE AKTIENGESELLSCHAFT,PATENT AND TRADEMARKET (3 °) Priority requested from the (71) KABEL- AND METALIWERKE GUTEHOFFNUNGSHUTE AKTIENGESELLSCHAFT,

Yahrenwalder Strasse 271» 3000 Hannover, DE, (72) Opfinder: Bernd Eilhardt, Brandriede 2, 3001 Vinnhorst, DE: Ger= hard Ziemek, Harnisohstr. 6, 3000 Hannover, DE, (74) Fuldmægtig under segens behandling:Yahrenwalder Strasse 271 »3000 Hanover, DE, (72) Inventor: Bernd Eilhardt, Brandriede 2, 3001 Vinnhorst, DE: Ger = hard Ziemek, Harnisohstr. 6, 3000 Hanover, DE, (74) Plenipotentiary:

Firmaet Chas. Hude.The company Chas. Hude.

(54) Fremgangsmåde ved kontinuerlig fremstilling af varmeisolerede ledningsrør.(54) Method of continuous manufacture of heat insulated conduits.

Den foreliggende opfindelse angår en fremgangsmåde ved kontinuerlig fremstilling af varmeisolerende ledningsrør, og af den art der er angivet i kravets indledning.The present invention relates to a process for the continuous manufacture of heat insulating conduits, and of the kind set forth in the preamble of claim.

Bøjelige metalrør, som er forsynet med en bøjelig plastindhylning, f.eks. bøjelige kobberrør, der indelukkes i en sådan indhylning, benyttes overalt, hvor det kommer an på at beskytte stoffer, som er transporteret i røret, mod temperaturudveksling med omgivelserne.Flexible metal pipes which are provided with a flexible plastic casing, e.g. flexible copper tubes enclosed in such a casing are used wherever it is necessary to protect substances transported in the pipe against temperature exchange with the surroundings.

Rør, som er belagt med en plastindhylning af et skumstof, har sær- 2 142268 lige fordele i forhold til metalrør, hvis indhylninger er udformet kompakt. Kompakte indhylninger kan ganske vist omfatte langsgående kanaler til opnåelse af en stor varmeisolering, men disse langsgående kanaler kan ifølge indhøstede erfaringer være årsag til korrosionsdannelser, som angriber metalrørets yderflade. Dannelser af langsgående kanaler er dog udelukket, når man benytter en isolations indhylning af et egnet skumstof.Pipes coated with a plastic wrap of a foam have particular advantages over metal pipes whose casings are compactly designed. Compact envelopes may include longitudinal ducts to achieve a large thermal insulation, but these longitudinal ducts may, according to experience gained, cause corrosion formation which attacks the outer surface of the metal tube. However, formation of longitudinal channels is excluded when using an insulating envelope of a suitable foam.

Der kendes en fremgangsmåde til fremstilling af en varmeisolerende indhylning af bøjeligt skumstof på et blankt, bøjeligt metalrør, ved hvilket man ved hjælp af en extruder sprøjter et tyndt lag af op-skumbart plast på metalrøret, hvorpå plasten i tilslutning hertil bringes til opskumning. Denne fremgangsmåde arbejder meget økonomisk, dog udviser de efter denne fremgangsmåde fremstillede rør den ulempe, at isolationslaget ikke udviser tilstrækkelig styrke og tempera turbestandighed ved mange anvendelsesformål, jvf. beskrivelsen til tysk fremlæggelsesskrift nr. 1.504.632.A method is known for producing a heat-insulating envelope of flexible foam on a glossy, flexible metal tube, by which a thin layer of foamable plastic is sprayed onto the metal tube by means of which the plastic is subsequently foamed. This method works very economically, however, the tubes made according to this method exhibit the disadvantage that the insulation layer does not exhibit sufficient strength and temperature resistance for many applications, cf.

Fra beskrivelsen til tysk offentliggørelsesskrift nr. 1.960.932 kendes endvidere en fremgangsmåde til fremstilling af varmeisolerende ledningsrør, ved hvilken en afstandsholder spiralagtigt påføres metalrøret, og hvor en folie ved en langsløbende indføring formes til et opspaltet rør om denne dannelse, hvorefter der i den åbne spalte inddryppes en opskummelig plast, hvorpå til sidst folien svejses langs dens båndkanter. Efter foliens sammensvejsning begynder skumstoffet at skumme op og udfylder derved det ringformede rum mellem metalrøret og folien. Også for denne fremgangsmåde gælder det ovenfor anførte.Further, from the specification of German publication specification No. 1,960,932 there is known a method for producing heat-insulating conduit, in which a spacer is spirally applied to the metal tube and in which a foil is formed at a longitudinal insertion into a split tube about this formation, after which in the open slit is a foamable plastic, and the foil is finally welded along its ribbon edges. Following the welding of the foil, the foam material begins to foam up, thereby filling the annular space between the metal tube and the foil. This process also applies to the above.

Fra beskrivelsen til U.S.A. patentskrift nr. 3.649.730 kendes en fremgangsmåde til at belægge et metalrør med en kappe. Metalrøret føres gennem en extruderform, hvor en kappe bestående af en blanding af en syntetisk plast og et opskumningsmiddel extruderes på rørets ydre overflade og underkastes opskumning inden for formens begrænsning. Efterhånden som det kappeklædte rør kommer ud af formen, føres det gennem et ringformet organ med en indre diameter, der er lidt mindre end den opskummede kappes ydre diameter, således at kappens ydre overfladelag deformeres til et kontinuerligt glat lag, 3 142260 hvorefter det kappekladte rør køles. Ved denne kendte fremgangsmåde kan man kun opnå en relativ ubetydelig massefylde for den op-skummede plast på mellem o,2 og 0,4 g/cm . Såfremt man vil opnå en større opskumningsgrad, dvs. en lavere massefylde, skal plastsmelten gøres mere tyndtflydende. Dette betyder imidlertid, at smelten efter påføringen drypper ned fra dette, og at man ikke kan opnå et ensartet tykt skumplastlag. For overhovedet at kunne extrudere en opskummelig plastblanding er det da også ifølge denne kendte teknik nødvendigt at benytte forskellige foranstaltninger, der fordyrer fremgangsmåden. Det kræves f.eks., at man evakuerer mellemrummet mellem røret og extruderboringen for at sikre, at skumstofkappen lægger sig an mod røret. Endvidere må opskumningen allerede indledes i extruderen. Sker der ved denne fremgangsmåde af en eller anden årsag en afbrydelse, så kan opskumningen og den umiddelbart bagefter følgende hærdning ikke afbrydes, dvs., at smelten skummer op inden i extruderen og hærder der. Dette nødvendiggør, at extruderen tages ud af drift i længere tid for at rengøres.From the description to U.S.A. U.S. Patent No. 3,649,730 discloses a method of coating a metal tube with a sheath. The metal tube is passed through an extruder mold, wherein a sheath consisting of a mixture of a synthetic plastic and a foaming agent is extruded onto the outer surface of the tube and subjected to foaming within the confining of the mold. As the sheathed tube emerges from the mold, it is passed through an annular member having an inner diameter slightly smaller than the outer diameter of the foamed sheath such that the outer surface layer of the sheath is deformed into a continuous smooth layer, after which the sheathed tube cooled. By this known method, only a relatively insignificant density of the foamed plastic of between 0, 2 and 0.4 g / cm can be obtained. If a greater degree of foaming is achieved, ie. a lower density, the plastic melt should be made more thin liquid. However, this means that after the application the melt drips down from this and that a uniform thick foam plastic layer cannot be obtained. Therefore, in order to be able to extrude a foamable plastic mixture at all, it is also necessary according to this known technique to use various measures which expensive the process. For example, it is required to evacuate the gap between the tube and the extruder bore to ensure that the foam cover adheres to the tube. Furthermore, foaming must already be initiated in the extruder. If, for some reason, this process occurs, an interruption, then the foaming and the immediately following hardening cannot be interrupted, i.e., the melt foams inside the extruder and hardens there. This necessitates extruding the extruder for a longer period of time for cleaning.

Det er den foreliggende opfindelses formål at anvise en fremgangsmåde til kontinuerlig fremstilling af varmeisolerede ledningsrør med en skumplastisolering, som udviser en større temperaturbestandighed og en større mekanisk styrke end de hidtil kendte, og hvor der umiddelbart dannes en kappe, der ensartet omgiver røret, og hvor man får en stor opskumningsgrad.SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for the continuous manufacture of heat insulated conduits having a foam plastic insulation which exhibits a greater temperature resistance and greater mechanical strength than the prior art, and immediately forming a jacket uniformly surrounding the tube and wherein one gets a high degree of foaming.

Dette formål tilgodeses ifølge den foreliggende opfindelse ved, at den indledningsvist omtalte fremgangsmåde er ejendommelig ved det i den kendetegnende del af kravet anførte. Ved at overskride tværbindingsmidlets sønderdelingstemperatur indledes plastens tværbinding. Ved f.eks. en tværbindingsgrad på 10 til 20%, der er fremherskende, når opskumningsmidlets sønderdelingstemperatur nås, bliver plastsmelten så sej, at den ganske vist endnu godt lader sig extrudere - dvs., at dens flydeevne stadig er meget god - men dog optager de fra opskumningsmidlet frigjorte luftartblærer i en temmelig jævn fordeling i form af små hulrum.This object is met in accordance with the present invention in that the method mentioned in the preamble is characterized by the characterizing part of the claim. By exceeding the decomposition temperature of the crosslinking agent, the plastic crosslinking is initiated. For example, a crosslinking rate of 10 to 20%, which is prevalent when the decomposition temperature of the foaming agent is reached, the plastic melt becomes so cool that it is still extrudable - that is, its flowability is still very good - but still it absorbs from the foaming agent. vesicles in a fairly even distribution in the form of small cavities.

Sagt med andre ord opnår man ved tværbindingen, at smeltens viskositet forhøjes, således at der dannes en kappe, der på ensartet må- 142268 4 de omgiver røret, og hvor der ved en yderligere temperaturforhøjelse sker en sønderdeling af opskumningsmidlet, hvorved opskumningen indledes; viskositetens forøgelse bevirker endvidere, at de luftblærer, der frigøres af opskumningsmidlet forbliver inden for kappen og dermed bidrager til at opnå en høj opskumningsgrad. I praksis forløber fremgangsmåden ifølge den foreliggende opfindelse på en sådan måde, at smeltens temperatur forhøjes inden i extruderen så meget, at tværbindingsmidlets sønderdelingstemperatur overskrides, og at opskumningen indledes gennem en eventuelt udefra kommende temperaturpåvirkning, efter at plasten har forladt extruderens mundstykke.In other words, by the cross-linking, the viscosity of the melt is obtained, so as to form a sheath which uniformly surrounds the tube, and where, at a further temperature rise, the foaming agent decomposes, thereby initiating the foaming; Furthermore, the increase in viscosity causes the air vesicles released by the foaming agent to remain within the jacket and thus contribute to a high degree of foaming. In practice, the process of the present invention proceeds in such a way that the temperature of the melt is increased within the extruder to such an extent that the decomposition temperature of the cross-linking agent is exceeded, and that the foaming is initiated through any extraneous temperature influence after the plastic has left the extruder nozzle.

Som termoplast anvendes polyethylen, polyvinylchlorid, polybuten, polypropylen og copolymere af disse. Medens de hidtil benyttede skumstoffer af blødt polyethylen, polyurethan og så videre var bestandige indtil 90°C og i særlige tilfælde også indtil 100°C, muliggør fremgangsmåden ifølge den foreliggende opfindelse fremstilling af rør, der er bestandige indtil 120°C. Tværbindingsprocessen forhindrer derved, at plasten drypper ned fra det rør, der skal isoleres.Polyethylene, polyvinyl chloride, polybutene, polypropylene and copolymers thereof are used as thermoplastics. While the foam materials made of soft polyethylene, polyurethane, and so far have been resistant to up to 90 ° C and in special cases also up to 100 ° C, the process of the present invention enables the production of tubes resistant up to 120 ° C. The cross-linking process thereby prevents the plastic from dripping from the pipe to be insulated.

Ved udøvelsen af fremgangsmåden ifølge opfindelsen er det hensigtsmæssigt, at der før plastlagets extrudering på metalrøret anbringes en folie, der hænger ved eller bindes til skumplastlaget. Påføringen af folien på metalrøret forud for isoleringslagets påføring har den fordel, at røret senere til brug for forbindelse ved et tilslutningssted nemt kan afisoleres. Folien, der klæber sammen med skum-plastlaget, forhindrer endvidere, at skumretningen forløber i rørets længderetning.In practicing the method according to the invention, it is convenient that prior to the extrusion of the plastic layer, a foil which is adhered to or bonded to the foam plastic layer is applied. The application of the foil to the metal pipe prior to the application of the insulating layer has the advantage that the pipe can later be easily de-insulated for use for connection at a connection point. The foil adhering to the foam-plastic layer further prevents the foam direction from extending in the longitudinal direction of the tube.

Det har vist sig særlig fordelagtigt, at der på metalrøret extrude-res en blanding bestående af 100 dele hård polyethylen, 2 dele peroxid, 2 dele af et drivmiddel og 0,5 dele af et ældningsmodvirkende middel. Herved får man en kappe, der har en god bestandighed og der 3 er sikret en massefylde på 0,05 g/cm .It has been found particularly advantageous to extrude on the metal tube a mixture of 100 parts of hard polyethylene, 2 parts of peroxide, 2 parts of a propellant and 0.5 parts of an anti-aging agent. This gives a sheath having a good resistance and a density of 0.05 g / cm is ensured.

Opskumningen bør foretages ved en temperatur, der ligger lidt over tværbindingsmidlets dekomponeringstemperatur. Herved kan man fordelagtigt udnytte, at tværbindingen er en eksoterm reation, der opvarmerThe foaming should be done at a temperature slightly above the decomposition temperature of the crosslinking agent. Hereby one can advantageously take advantage of the fact that the cross-linking is an exothermic heating that heats

DK253975A 1975-06-04 1975-06-04 Method of continuous manufacture of heat insulated conduit. DK142268B (en)

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DK253975A DK142268B (en) 1975-06-04 1975-06-04 Method of continuous manufacture of heat insulated conduit.

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DK253975A DK142268B (en) 1975-06-04 1975-06-04 Method of continuous manufacture of heat insulated conduit.
DK253975 1975-06-04

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DK253975A DK253975A (en) 1976-12-05
DK142268B true DK142268B (en) 1980-10-06
DK142268C DK142268C (en) 1981-03-02

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DK253975A (en) 1976-12-05

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