CH655989A5

CH655989A5 - Collar connection for heat-insulated pipelines

Info

Publication number: CH655989A5
Application number: CH4689/82A
Authority: CH
Inventors: Albert Elbeshausen; Wolfgang Artschwager
Original assignee: Kabelmetal Electro Gmbh
Priority date: 1982-02-17
Filing date: 1982-08-04
Publication date: 1986-05-30
Also published as: DK12494A; DK325382A; DK171835B1

Abstract

Located around an inner pipe (5) which is carrying a medium is a heat-insulation layer (6) consisting of foamed plastic, and around this layer there is an outer sheath (7) consisting of plastic. Those ends of two inner pipes (5) from which the foam has been cleared are welded to one another. The actual sleeve body consists of a plastic strip (1) which is formed with an overlap (8) over the connecting point. This plastic strip (1) is welded to the outer sheath (7), by means of a heating strip which can be heated electrically, both in the region of the overlap (8) and in the region where it rests on the outer sheath (7). <IMAGE>

Description

       

  
 

**WARNUNG** Anfang DESC Feld konnte Ende CLMS uberlappen **.

 



   PATENTANSPRÜCHE
1. Muffenverbindung für wärmeisolierte Leitungsrohre, die aus einem mediumführenden Innenrohr (5), einer das Innenrohr (5) umgebenden Wärmeisolationsschicht (6) aus aufgeschäumtem Kunststoff und einem Aussenmantel (7) aus einem Kunststoffbestehen, wobei die von Schaumstoff freien Enden der Innenrohre (5) zweier Rohrschüsse miteinander verschweisst sind, die Verbindungsstelle durch eine auf den Aussenmantelenden aufliegende Muffe abgedeckt und der zwischen dem Innenrohr (5) und der Muffe befindliche Ringraum ausgeschäumt ist, dadurch gekennzeichnet, dass die Muffe aus einem mit Überlappungen (8) über die Verbindungsstelle geformten Kunststoffband (1) besteht und ein elektrisch beheizbares Heizband (2) angeordnet ist,

   mit welchem das Kunststoffband (1) sowohl im Bereich der Naht der Überlappung (8) als auch im Bereich der Auflage auf dem Aussenmantel (7) verschweisst ist.



   2. Muffenverbindung nach Patentanspruch 1, dadurch gekennzeichnet, dass das elektrisch beheizte Heizband (2) in Form eines Mäanders im Kantenbereich des Kunststoffbandes (1) angeordnet ist
Die vorliegende Erfindung betrifft eine Muffenverbindung für wärmeisolierte Leitungsrohre, die aus einem mediumführenden Innenrohr, vorzugsweise aus Stahl, einer das Innenrohr umgebenden Wärmeisolationsschicht aus aufgeschäumtem Kunststoff, vorzugsweise Polyurethan und einem Aussenrohr aus Kunststoff bestehen, wobei die von Schaumstoff freien Enden der Innenrohre zweier Rohrschüsse miteinander verschweisst sind, die Verbindungsstelle durch eine auf den Aussenrohrenden aufliegende Muffe abgedeckt und der zwischen dem Innenrohr und der Muffe befindliche Ringraum ausgeschäumt ist.



   Für den Transport erwärmter oder gekühlter Medien, insbesondere für den Transport von Fernwärme ist es bekannt, sogenannte Verbundrohre zu verwenden. Hierbei handelt es sich um werksseitig vorisolierte Rohre von z.B. 6 bis 12 m Länge, die an der Montagestelle zu dem eigentlichen Rohrstrang verbunden werden. Hierbei werden die vorstehenden Enden der Innenrohre miteinander verschweisst und die Verbindungsstelle wird durch eine auf den Aussenmänteln der verbundenen Rohre aufliegende Muffe abgedeckt, und der Ringraum zwischen der Muffe und dem Innenrohr wird mit einem Schaumstoff ausgeschäumt
Muffenverbindungen waren bislang immer die Schwachstelle dieser Art von Fernwärmeleitung, da die Feuchtigkeit z.B. aus dem Erdboden in den Ringraum zwischen dem Innenrohr und dem Aussenrohr eindringen konnte und den Schaumstoff zerstörte. Vielfach kam es auch zu einer Korrosion am Innenrohr.



   Bei der Verbindung von derartigen Verbundrohren ging man bisher so vor, dass über ein Rohrende zweier zu verbindender Rohrlängen ein Muffenrohr geschoben wurde, die Innenrohre miteinander verschweisst wurden, das Muffenrohr über die Verbindungsstelle geschoben, gegenüber den Aussenmänteln der Rohrlänge mittels Schrumpfschläuchen abgedichtet, und anschliessend der Ringraum ausgeschäumt wurde. Diese Muffenverbindung ist zwar über längere Zeit gesehen dicht, jedoch ist sie sehr aufwendig in der Herstellung und Montage.



   Die Erfindung bezweckt eine Muffenverbindung zu schaffen, die wesentlich kostengünstiger in der Herstellung und Montage und auch über einen längeren Zeitraum dicht, insbesondere gegen anstehendes Grundwasser, ist.



   Die erfindungsgemässe Muffenverbindung entspricht den kennzeichnenden Merkmalen des Patentanspruchs 1.



   Neben den sich aus der Aufgabenstellung direkt ergebenden Vorteilen, weist die erfindungsgemässe Muffenverbindung noch den Vorteil auf, dass auf ein relativ teures Muffenrohr verzichtet werden kann und statt dessen der Muffenkörper aus einem wesentlich preiswerteren Material erstellt werden kann. Bei der Auswahl des Kunststoffes sollte darauf geachtet werden, dass das Material für den Muffenkörper die gleiche Beschaffenheit wie das Material des Aussenmantels der wärmeisolierten Leitungsrohre hat. Vorteilhafterweise verwendet man ein Polyäthylenband, welches durchscheinend ist, so dass man beim abschliessenden Ausschäumen den Aufschäumungsvorgang beobachten und somit Lunkerstellen vermeiden kann.



     Zweckmässigerweise    ist das elektrisch beheizbare Band in Form eines Mäanders im Kantenbereich des Kunststoffbandes angeordnet. Beim Anschluss an eine Stromquelle heizt sich das Band aufgrund von Widerstandserwärmung auf und schmilzt dabei die angrenzenden Kunststoffschichten an, die miteinander verschweissen. Wesentlich ist dabei, dass sowohl im Bereich der Auflagefläche auf dem Aussenrohr als auch im Bereich der Überlappungsnaht ein leichter Anpressdruck vorherrscht.



   Nachfolgend wird anhand der Zeichnung ein Ausfüh   rungsbeispiel    des Erfindungsgegenstandes beschrieben.



   Fig. 1 zeigt das Kunststoffband,
Fig. 2 zeigt einen Schnitt durch die Muffenverbindung,
Fig. 3 zeigt die fertige Muffenverbindung.



   In der Fig. 1 ist ein Kunststoffband 1 dargestellt, in dessen Randbereichen ein Heizband 2 angeordnet ist.



   Das Kunststoffband 1 besteht zweckmässigerweise aus Polyäthylen und hat beispielsweise eine Dicke von etwa vier mm. Um den Heizdraht 2 zu erwärmen, werden die Enden 3 und 4 an eine nicht dargestellte Stromquelle angeschlossen.



  In Folge der Widerstandserwärmung des Drahtes 2 erweicht das Kunststoffmaterial im benachbarten Bereich des Drahtes und ist somit in den schweissfähigen Zustand überführt.



   In der Fig. 2 ist ein Schnitt durch die Muffenverbindung dargestellt. Hierin ist mit 5 das mediumführende Innenrohr, mit 6 die Wärmeisolationsschicht aus aufgeschäumtem Kunststoff, mit 7 der Kunststoffaussenmantel bezeichnet.



  Auf dem Kunststoffaussenmantel liegt das Kunststoffband 1, und zwar mit einer Überlappung 8. Das Kunststoffband 1 wird mittels einer Manschette 9 auf den Aussenmantel 7 gedrückt, wobei gleichzeitig der Bereich der Überlappung 8 zusammengedrückt wird. Zum Verspannen der Manschette 9 dient eine Schraubzwinge 10, deren Backen 11 und 12 hinter Abkantungen 13 und 14 der Manschette 9 greifen. Die Spannbacken 11 und 12 werden nach dem Umlegen der Manschette 9 mittels einer Gewindespindel 15 einander angenähert und dabei die Manschette 9 auf den Aussenmantel 7 gedrückt. Im vorgespannten Zustand wird der Heizdraht 2 aufgeheizt, und nach dem Schweissvorgang die Manschette 9 von der Muffenstelle entfernt.



   Die Fig. 3 zeigt die fertige Muffenverbindung, bei der das Kunststoffband 1 auf den Aussenmänteln 7 aufliegend um die Verbindungsstelle herumgelegt und im Bereich der schraffierten Flächen mit den Aussenmänteln 7 bzw. im Bereich der Überlappung 8 verschweisst ist.



   Eine gegebenenfalls vorgesehene Öffnung im Kunststoffband 1, die dazu dient, den Raum zwischen dem Innenrohr 5 und dem Kunststoffband 1 mit Schaumstoff auszufüllen, kann in entsprechender Weise durch Auflegen einer Kunststoffscheibe und Verschweissen der Kunststoffscheibe mit dem Kunststoffband 1 wie oben beschrieben abgedichtet werden. 



  
 

** WARNING ** beginning of DESC field could overlap end of CLMS **.

 



   PATENT CLAIMS
1.Socket connection for heat-insulated conduit pipes, which consist of a medium-conducting inner pipe (5), a heat insulation layer (6) surrounding the inner pipe (5) made of foamed plastic and an outer jacket (7) made of plastic, the ends of the inner pipes (5 ) two pipe sections are welded to one another, the connection point is covered by a sleeve resting on the outer jacket ends and the annular space between the inner pipe (5) and the sleeve is foamed, characterized in that the sleeve consists of a joint formed with overlaps (8) over the connection point Plastic tape (1) and an electrically heated heating tape (2) is arranged,

   with which the plastic band (1) is welded both in the area of the seam of the overlap (8) and in the area of the support on the outer jacket (7).



   2. Socket connection according to claim 1, characterized in that the electrically heated heating tape (2) is arranged in the form of a meander in the edge region of the plastic tape (1)
The present invention relates to a socket connection for heat-insulated conduit pipes, which consist of a medium-conducting inner pipe, preferably made of steel, a heat insulation layer surrounding the inner pipe made of foamed plastic, preferably polyurethane, and an outer pipe made of plastic, the ends of the inner pipes of two pipe sections free of foam being welded together are, the connection point is covered by a sleeve resting on the outer tube ends and the annular space located between the inner tube and the sleeve is foamed.



   It is known to use so-called composite pipes for the transport of heated or cooled media, in particular for the transport of district heating. These are factory-insulated pipes from e.g. 6 to 12 m in length, which are connected to the actual pipe string at the assembly point. Here, the projecting ends of the inner tubes are welded to one another and the connection point is covered by a sleeve resting on the outer jackets of the connected tubes, and the annular space between the sleeve and the inner tube is foamed with a foam
So far, socket connections have always been the weak point of this type of district heating pipe, as the moisture e.g. could penetrate from the ground into the annular space between the inner tube and the outer tube and destroyed the foam. In many cases there was also corrosion on the inner tube.



   When connecting composite pipes of this type, a procedure was previously used such that a sleeve pipe was pushed over one pipe end of two pipe lengths to be connected, the inner pipes were welded together, the sleeve pipe was pushed over the connection point, sealed against the outer jackets of the pipe length using shrink sleeves, and then the Annulus was foamed. This sleeve connection is tight for a long time, but it is very complex to manufacture and assemble.



   The invention aims to provide a socket connection which is considerably less expensive to manufacture and assemble and which is also leakproof over a longer period of time, in particular against groundwater present.



   The socket connection according to the invention corresponds to the characterizing features of patent claim 1.



   In addition to the advantages resulting directly from the task, the sleeve connection according to the invention also has the advantage that a relatively expensive sleeve pipe can be dispensed with and instead the sleeve body can be made from a much cheaper material. When selecting the plastic, care should be taken that the material for the socket body has the same properties as the material of the outer jacket of the heat-insulated conduit. Advantageously, a polyethylene tape is used, which is translucent, so that the foaming process can be observed during the final foaming and thus blowholes can be avoided.



     The electrically heatable band is expediently arranged in the form of a meander in the edge region of the plastic band. When connected to a power source, the strip heats up due to resistance heating and melts the adjacent plastic layers that weld together. It is essential here that a slight contact pressure prevails both in the area of the contact surface on the outer tube and in the area of the overlap seam.



   An exemplary embodiment of the subject matter of the invention is described below with reference to the drawing.



   1 shows the plastic band,
2 shows a section through the socket connection,
Fig. 3 shows the finished socket connection.



   1 shows a plastic strip 1, in the edge regions of which a heating strip 2 is arranged.



   The plastic band 1 suitably consists of polyethylene and has a thickness of about four mm, for example. In order to heat the heating wire 2, the ends 3 and 4 are connected to a power source, not shown.



  As a result of the resistance heating of the wire 2, the plastic material softens in the adjacent area of the wire and is thus converted into the weldable state.



   2 shows a section through the socket connection. Herein, 5 denotes the medium-carrying inner tube, 6 the heat insulation layer made of foamed plastic, 7 the plastic outer jacket.



  The plastic tape 1 lies on the plastic outer jacket, specifically with an overlap 8. The plastic tape 1 is pressed onto the outer jacket 7 by means of a sleeve 9, the area of the overlap 8 being compressed at the same time. A screw clamp 10 is used to clamp the cuff 9, the jaws 11 and 12 of which grip behind the folds 13 and 14 of the cuff 9. After the sleeve 9 has been folded over, the clamping jaws 11 and 12 are brought closer to one another by means of a threaded spindle 15 and the sleeve 9 is pressed onto the outer jacket 7. In the pretensioned state, the heating wire 2 is heated and, after the welding process, the sleeve 9 is removed from the socket point.



   3 shows the finished socket connection, in which the plastic tape 1 is placed on the outer sheaths 7 around the connection point and is welded to the outer sheaths 7 in the area of the hatched areas or in the area of the overlap 8.



   An optionally provided opening in the plastic band 1, which serves to fill the space between the inner tube 5 and the plastic band 1 with foam, can be sealed in a corresponding manner by placing a plastic disc and welding the plastic disc with the plastic band 1 as described above.

Claims

PATENT CLAIMS 1.Socket connection for heat-insulated conduit pipes, which consist of a medium-conducting inner pipe (5), a heat insulation layer (6) surrounding the inner pipe (5) made of foamed plastic and an outer jacket (7) made of plastic, the ends of the inner pipes (5 ) two pipe sections are welded to one another, the connection point is covered by a sleeve resting on the outer jacket ends and the annular space between the inner pipe (5) and the sleeve is foamed, characterized in that the sleeve consists of a joint formed with overlaps (8) over the connection point Plastic tape (1) and an electrically heated heating tape (2) is arranged,

with which the plastic band (1) is welded both in the area of the seam of the overlap (8) and in the area of the support on the outer jacket (7).

2. Socket connection according to claim 1, characterized in that the electrically heated heating tape (2) is arranged in the form of a meander in the edge region of the plastic tape (1) The present invention relates to a socket connection for heat-insulated conduit pipes, which consist of a medium-conducting inner pipe, preferably made of steel, a heat insulation layer surrounding the inner pipe made of foamed plastic, preferably polyurethane, and an outer pipe made of plastic, the ends of the inner pipes of two pipe sections free of foam being welded together are, the connection point is covered by a sleeve resting on the outer tube ends and the annular space located between the inner tube and the sleeve is foamed.

It is known to use so-called composite pipes for the transport of heated or cooled media, in particular for the transport of district heating. These are factory-insulated pipes from e.g. 6 to 12 m in length, which are connected to the actual pipe string at the assembly point. Here, the projecting ends of the inner tubes are welded to one another and the connection point is covered by a sleeve resting on the outer jackets of the connected tubes, and the annular space between the sleeve and the inner tube is foamed with a foam So far, socket connections have always been the weak point of this type of district heating pipe, as the moisture e.g. could penetrate from the ground into the annular space between the inner tube and the outer tube and destroyed the foam. In many cases there was also corrosion on the inner tube.

When connecting composite pipes of this type, a procedure was previously used such that a sleeve pipe was pushed over one pipe end of two pipe lengths to be connected, the inner pipes were welded together, the sleeve pipe was pushed over the connection point, sealed against the outer jackets of the pipe length using shrink sleeves, and then the Annulus was foamed. This sleeve connection is tight for a long time, but it is very complex to manufacture and assemble.

The invention aims to provide a socket connection which is considerably less expensive to manufacture and assemble and which is also leakproof over a longer period of time, in particular against groundwater present.

The socket connection according to the invention corresponds to the characterizing features of patent claim 1.

In addition to the advantages resulting directly from the task, the sleeve connection according to the invention also has the advantage that a relatively expensive sleeve pipe can be dispensed with and instead the sleeve body can be made from a much cheaper material. When selecting the plastic, care should be taken that the material for the socket body has the same properties as the material of the outer jacket of the heat-insulated conduit. Advantageously, a polyethylene tape is used, which is translucent, so that the foaming process can be observed during the final foaming and thus blowholes can be avoided.

The electrically heatable band is expediently arranged in the form of a meander in the edge region of the plastic band. When connected to a power source, the strip heats up due to resistance heating and melts the adjacent plastic layers that weld together. It is essential here that a slight contact pressure prevails both in the area of the contact surface on the outer tube and in the area of the overlap seam.

An exemplary embodiment of the subject matter of the invention is described below with reference to the drawing.

1 shows the plastic band, 2 shows a section through the socket connection, Fig. 3 shows the finished socket connection.

1 shows a plastic strip 1, in the edge regions of which a heating strip 2 is arranged.

The plastic band 1 suitably consists of polyethylene and has a thickness of about four mm, for example. In order to heat the heating wire 2, the ends 3 and 4 are connected to a power source, not shown.

As a result of the resistance heating of the wire 2, the plastic material softens in the adjacent area of the wire and is thus converted into the weldable state.

2 shows a section through the socket connection. Herein, 5 denotes the medium-carrying inner tube, 6 the heat insulation layer made of foamed plastic, 7 the plastic outer jacket.

The plastic tape 1 lies on the plastic outer jacket, specifically with an overlap 8. The plastic tape 1 is pressed onto the outer jacket 7 by means of a sleeve 9, the area of the overlap 8 being compressed at the same time. A screw clamp 10 is used to clamp the cuff 9, the jaws 11 and 12 of which grip behind the folds 13 and 14 of the cuff 9. After the sleeve 9 has been folded over, the clamping jaws 11 and 12 are brought closer to one another by means of a threaded spindle 15 and the sleeve 9 is pressed onto the outer jacket 7. In the pretensioned state, the heating wire 2 is heated and, after the welding process, the sleeve 9 is removed from the socket point.

3 shows the finished sleeve connection, in which the plastic tape 1 lies on the outer sheaths 7, lying around the connection point and is welded to the outer shells 7 in the area of the hatched areas or in the area of the overlap 8.

An optionally provided opening in the plastic band 1, which serves to fill the space between the inner tube 5 and the plastic band 1 with foam, can be sealed in a corresponding manner by placing a plastic disc and welding the plastic disc with the plastic band 1 as described above. ** WARNING ** End of CLMS field could overlap beginning of DESC **.