DK157406B

DK157406B - PROCEDURE FOR PUTTING A PIPE PIPE FOR HOT MEDIA

Info

Publication number: DK157406B
Application number: DK150883A
Authority: DK
Inventors: Peter Huber
Original assignee: Meier Schenk Ag
Priority date: 1982-05-03
Filing date: 1983-04-05
Publication date: 1990-01-02
Also published as: SE8302461D0; DE3216477C2; DK150883D0; DE3216477A1; DK150883A; SE8302461L; NL8301360A; SE454456B; CH660221A5; DK157406C

Description

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DK 157406 BDK 157406 B

Opfindelsen angår en fremgangsmåde til nedlægning af en rørledning til varme medier, bestående af et medieførende inder-rør af metal, et inderrøret omgivende varmeisolationslag såvel som et ydre kapperør, ved hvilken fremgangsmåde de enkelte 5 rørledningsafsnit forbindes indbyrdes, og rørledningsstrengen forlænges ved hjælp af opvarmet damp og derefter fikseres i denne tilstand.BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method for laying a pipeline for hot media consisting of a metal conducting inner tube, an inner tube surrounding heat insulation layer as well as an outer casing tube, by which method each of the pipeline sections is interconnected and the pipeline string is extended by means of heated. steam and then fixed in this state.

Fra tysk offentliggørelsesskrift nr. 2.707.799 er det kendt at 10 forspænde en rørledning til transport af varme medier ved en fortemperering af rørledningen og en efterfølgende fyldning, idet der til fortempereri ngen ledes varm luft eller gas eller opvarmet væske gennem ledningen. En ulempe ved denne fremgangsmåde er, at energiforbruget til opvarmning af gasserne 15 eller væskerne er meget højt, eftersom der kræves store mængder opvarmet medium til tilvejebringelse af den nødvendige forspændingstemperatur af rørledningsstrengen. En temperatur af mediet på f.eks. den ønskede forspændingstemperatur giver et langvarigt opvarmningsfor 1øb. Selv om gassen afkøles under 20 tempereringen, afgives den fra rør 1 edn ingsstrengen med en temperatur, der ligger væsentligt over omgivelsernes temperatur.From German Publication No. 2,707,799, it is known to bias a pipeline for transporting hot media by an attenuation of the pipeline and a subsequent filling, by which hot air or gas or heated liquid is passed through the pipeline. A disadvantage of this method is that the energy consumption for heating the gases 15 or liquids is very high, since large amounts of heated medium are required to provide the required biasing temperature of the pipeline string. A temperature of the medium of e.g. the desired bias temperature provides a long-lasting heating run. Although the gas is cooled below the temperature, it is emitted from tube 1 of the sealing string at a temperature substantially above ambient temperature.

Hvis forvarmningsmedi et er opvarmet til en temperatur, der er højere end den ønskede forspændingstemperatur, bliver rørled-25 ningen ved indgangsenden udvidet meget stærkt og ved afgangsenden kun udvidet en smule.If the preheating medium is heated to a temperature higher than the desired bias temperature, the conduit at the input end is expanded very strongly and at the outlet end only slightly expanded.

Tysk patentskrift nr. 2.909.475 angår en forspænd ingsmetode til et varmeisoleret ledningsrør bestående af et medieførende 30 inderrør, et varmeisolerende lag og en yderkappe i form af et stålrør. Efter nedlænging af rørstrengen ledes mættet vanddamp gennem inderrøret, og inderrøret fikseres i forlænget tilstand til yderrøret. Vanddampen har ved denne metode en temperatur på 100 °C, hvorved der medgår forholdsvis meget energi til op-35 nåelse af den ønskede forspænding.German Patent No. 2,909,475 relates to a biasing method for a heat-insulated conduit consisting of a medium-conducting inner tube, a heat-insulating layer and an outer casing in the form of a steel pipe. After the pipe string is lowered, saturated water vapor is passed through the inner tube and the inner tube is fixed in an extended state to the outer tube. In this method, the water vapor has a temperature of 100 ° C, whereby relatively much energy is consumed to achieve the desired bias.

Formålet med opfindelsen er at anvise, hvorledes den nævnte fremgangsmåde kan forbedres, således at der kræves væsentligtThe object of the invention is to show how the said method can be improved so that substantial

DK 157406 BDK 157406 B

2 mindre energi til forspending, og rørledningen over den betragtede længde opvarmes ensartet og derved udvider sig ensartet.2 less energy for biasing, and the pipeline over the considered length is uniformly heated, thereby expanding uniformly.

5 Dette formål er ifølge opfindelsen opnået ved, at den ene ende af inderrøret først lukkes tryktæt, at det indre rum af inder-røret evakueres, og at der derefter indføres vanddamp i det indre rum af inderrøret. Den væsentlige fordel består i, at der gennem evakueringen af inderrrummet kan arbejdes med vand-10 damp på under 100eC. Vanddampen kondenserer ved den koldere væg af inderrøret og afgiver derved kondensationsvarme til inderrøret. En yderligere fordel er, at varmeovergangen under en kondensation er væsentligt mere intensiv end ved gennemføring af en opvarmet gas.This object is achieved according to the invention in that one end of the inner tube is first closed tightly, that the inner space of the inner tube is evacuated and then water vapor is introduced into the inner space of the inner tube. The main advantage is that through the evacuation of the inner room, it is possible to work with water-10 steam below 100 ° C. The water vapor condenses at the colder wall of the inner tube, thereby delivering condensation heat to the inner tube. A further advantage is that the heat transfer during a condensation is substantially more intense than that of a heated gas.

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Under udøvelse af fremgangsmåden bliver der til den frie ende af inderrøret tilsluttet en dampkedel, og inderrummet af dampkedelen og inderrøret evakueres, idet dampkedelen fyldes med vand, og vandet opvarmes til forspændingstemperaturen. Allere-20 de under indføringen af vandet i dampkedelen bliver en del af vandet fordampet, eftersom trykket i det indre af dampkedelen henholdsvis inderrøret er mindre end damptrykket af vandet ved omgivelsernes temperatur. Ved en opvarmning af vandet i det indre af dampkedelen, eksempelvis ved hjælp af en gasbrænder, 25 fordeles vanddamp af øget temperatur ensartet over hele rør længden, og vanddampen kondenserer ved den koldere væg af inderrøret. Oerved strømmer der hele tiden damp tilbage og opvarmer rørvæggen. Gennem en regulering af temperaturen i var-mekedelen bliver kondensationstemperaturen og dermed forspæn-30 dingstemperaturen over den samlede rørlængde nøjagtigt over holdt. Det opståede kondensat kan opsamles i egnede kondensatbeholdere eller det kan ved en passende hældning af rørledningen flyde tilbage til kedelen. 1During the process, a steam boiler is connected to the free end of the inner tube and the inner space of the steam boiler and the inner tube is evacuated as the steam boiler is filled with water and the water is heated to the biasing temperature. Already during the introduction of the water into the steam boiler part of the water is evaporated, since the pressure in the interior of the steam boiler and the inner tube, respectively, is less than the steam pressure of the water at ambient temperature. By heating the water in the interior of the steam boiler, for example by means of a gas burner, water vapor of increased temperature is uniformly distributed over the entire pipe length, and the water vapor condenses at the colder wall of the inner pipe. With this, steam constantly flows back and heats the pipe wall. By regulating the temperature of the heater part, the condensation temperature and thus the biasing temperature over the total pipe length is accurately maintained. The resulting condensate can be collected in suitable condensate containers or it can flow back to the boiler at an appropriate slope of the pipeline. 1

Der kan med fordel evakueres med et tryk på mellem 5 og 15 mbar.It is advantageous to evacuate with a pressure of between 5 and 15 mbar.

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Fremgangsmåden ifølge opfindelsen er især hensigtsmæssig til forspænding af termisk isolerede ledningsrør af den art, hvor der er fast forbindelse mellem inderrøret og yderkappen. Efter opnåelse af forspændingstemperaturen lægges rørene i et sand-5 bed.The method according to the invention is particularly suitable for biasing thermally insulated conduits of a kind where there is a fixed connection between the inner tube and the outer casing. After reaching the bias temperature, the tubes are laid in a sand-bed.

Opfindelsen skal nærmere forklares i det følgende under henvisning til tegningen, som illustrerer fremgangsmåden ifølge opfindelsen.The invention will be explained in more detail below with reference to the drawing which illustrates the method according to the invention.

10 1 er en rørledningsstreng, der f.eks. er sammensvejst af flere enkelte rørlængder. Rørledningsstrengen 1 består af et medieførende inderrør 2 af stål, en yderkappe 3, der fortrinsvis er af formstof, og et varmeisolationslag mellem inderrøret 2 15 og yderkappen 3. Dette varmeisolationslag kan med fordel bestå af opskummet polyurethan. Inderrøret 2 lukkes tryktæt i enderne, eksempelvis ved hjælp af en kappe 4. Den anden ende af inderrøret 2 er sluttet til en kedel 5, hvis inderrum 6 er forbundet med en evakueringspumpe 7. Ved hjælp af en skyder 8 20 kan evakueringspumpen 7 afkobles fra inderrummet 6. På kedelen 5 sidder der desuden en forrådsbeholder 9, hvis forbindelse til inderrummet 6 kan åbnes henholdsvis lukkes ved hjælp af en skyder 10. Kedelen 5 har desuden en varmespiral 11 til opvarmning.10 1 is a pipeline string which e.g. is welded by several single pipe lengths. The pipeline string 1 consists of a medium conducting inner tube 2 of steel, an outer sheath 3 which is preferably of plastic material, and a heat insulation layer between the inner tube 2 15 and the outer sheath 3. This heat insulation layer can advantageously consist of foamed polyurethane. The inner tube 2 is closed tightly at the ends, for example by means of a sheath 4. The other end of the inner tube 2 is connected to a boiler 5, the inner space 6 of which is connected to an evacuation pump 7. By means of a slider 8 the evacuation pump 7 can be disconnected from In addition, the boiler 5 has a storage container 9, the connection of which to the interior space 6 can be opened or closed by means of a slider 10. The boiler 5 also has a heating coil 11 for heating.

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Fremgangsmåden ifølge opfindelsen er følgende:The process according to the invention is as follows:

Efter tilslutning af kedelen 5 til inderrøret 2 bliver evakueringspumpen 7 indkoblet, og inderrummet 6 af kedelen og dermed 30 inderrøret 2 evakueres til et tryk på af størrelsesordenen 5 mbar. Derefter lukkes skyderen 8, og trykket i kedelens 5 inderrum 6 overvåges. Derved kan der foretages en tæthedsafprøvning af rørledningsstrengen 1. Derefter åbnes skyderen 10, og fra forrådsbeholderen 9 indføres der vand i inderrummet 6 af 35 kedelen 5. En del af vandet fordampes og fordeles ensartet i inderrummet 6 og i det indre af det medieførende rør 2. Ved en temperatur af omgivelserne på f.eks. 20° C indstiller der sigAfter connecting the boiler 5 to the inner tube 2, the evacuation pump 7 is switched on and the inner space 6 of the boiler and thus the inner tube 2 is evacuated to a pressure of the order of 5 mbar. The slider 8 is then closed and the pressure in the inner space 6 of the boiler 5 is monitored. This allows a leak test of the pipeline string 1. Then the slider 10 is opened, and from the storage container 9 water is introduced into the inner space 6 of the boiler 5. A part of the water is evaporated and distributed uniformly in the inner space 6 and in the interior of the media-carrying pipe 2. At a temperature of the environment of e.g. 20 ° C is adjusting

Claims

A method for laying a pipeline for hot media, consisting of a media conducting inner tube (2) of metal, an inner tube surrounding heat insulation layer as well as an outer cap tube (3), by which method the individual pipeline sections are interconnected, and the pipeline string is extended by means of heated steam and then fixed in this state, characterized in that one end of the inner tube (2) is first closed tightly, that the inner space of the inner tube (2) is evacuated and that water steam is then introduced into it. the inner space of the inner tube (2).

Method according to claim 1, characterized in that the free end of the inner tube (2) is connected to a steam boiler 30 (5), evacuating the inner space (6) of the steam boiler and the inner tube (2) and introducing water into the steam boiler (5). and the water is heated to the bias temperature.

Method according to claim 1 or 2, characterized in that evacuated to a pressure of between 5 and 15 mbar.

Use of the method according to any of the preceding claims for biasing thermally insulated conduits of DK 157406B 5 the kind in which there is a fixed connection between the inner pipe {23 and the outer casing (3) (connecting pipe).

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