DE19652712C1 - Connection of double tubes with internally located conduit tube - Google Patents

Abstract

A welding sleeve is placed around each of the ends of the cover tube and has a number of heating wires. A shrink tube is pushed on, covering the intermediate space, and is shrunk. the ends of the cover tube and the shrink tube are welded to one another by heating the welding sleeve. The hollow space surrounded by the shrink tube is filled with a heat-insulating foam material and the filling aperture is closed. This filling aperture (12) is provided between the ends of the welding sleeve (7), arranged around the cover tube (3), where there is an intermediate space (9).

Description

The invention is concerned with the connection of double tubes that flow from an internal conduit for de media, a heat-insulating foam and a Jacket tube exist at the ends to be connected the ends of the line pipes are exposed and be welded together to form the ends of the jacket tube each a welding sleeve provided with heating wires a shrink tube covering the space is pushed on and shrunk on by heating the Welding sleeve the ends of the casing tubes and that Shrink tube are welded together by the Cavity surrounded by a cavity in the shrink tube existing filling opening with a heat-insulating foam stuffed and the fill opening is closed. Dop Pel tubes of this type can be found, for example, in district heating use.

In the case of a connection known from EP 0 075 901 A1, a placed between the casing tube and the shrink tube and with a Heating wire provided welding ring a tight weld bring about these pipe parts, and in DE 37 20 577 A1 a welding cuff is used, in which comb-like interlocking butt ends are provided, the one seamless welding over the entire scope of the ver secures welding pipe parts, even if their outer or The inside diameters differ greatly. Sweat rings can not be the deviating disadvantageous Outside and inside diameters can only be adjusted and adjusted difficult to attach. Have welding cuffs or bands the disadvantage that the heating resistance wires on their foreheads When softening the plastic mass, they end in Be can come and short circuit, so that the ange  sought sealing is not obtained. Has a disadvantage further out that the weld is not to the brim the casing tube is sufficient and therefore in this area between sheathed tube and shrink tube a narrow annular Space with gas bubble inclusions is formed can not be easily foamed. In a known way is used to foam the welded shrink tube enveloping cavity a filling opening approximately midway between or even further in front of the ends of the casing pipes Shrink tube incorporated. The pressed foam mass flows into the cavity, but also on the end faces the existing foam of the two double pipes air upholstery can arise, which can also be caused by additional Do not let ventilation openings be avoided. Air cushion however, due to the formation of moisture by con densation as well as for reasons of thermal insulation and also Stability of the pipe assembly can be avoided.

The object of the invention is therefore to create a verb which is simply a reliable and reproducible filling with foam, sealing and heat insulation allows.

This task is characterized by the in the characterizing part of the claim 1 specified features solved.

The one between the ends of the welding sleeve Gap initially prevents the heating wires when Softening come into contact with each other. The flipped Welding cuff is therefore even and when heated tightly with the casing tube and the previously shrunk Welded shrink tube. The foaming of the from Shrink tube enveloped cavity happens advantageously ter way from one end of the casing tube over the Mit te of the cavity towards the other end, so practical no air cushions can be formed. At the beginning Chen exposure of the conduit is in the double pipe existing foam expediently in the range of  Filling opening removed to fill the foam mass to allow in the cavity. The propellant can during of foaming escape without hindrance. In the end phase of the foaming is also the space between foamed the ends of the two welding sleeves. Finally, the two filling openings with one each Welding plugs welded gas and watertight and ver closed. A conical sweat plug is preferred used.

The integration of the new assembly steps leads to simpl cher way to a connection, the sealing and heat insulation is particularly reliable. That is alone very important because the seal between the man tele tubes and the shrink tube on the one hand and the expansion On the other hand, the degree of efficiency after assembly is not in practice or cannot be controlled non-destructively. The zuver The ease of this double pipe connection is a significant one che improvement because the emerging foam on the Pipe ends between the welding sleeves the optimal Displays the degree of filling.

An embodiment of the invention is in the drawing shown; it shows

Fig. 1 shows a connection of two double pipes, insulators with heat and the jacket tube, partially cut away in a top view,

Fig. 2 shows a part of the object of FIG. 1 in a longitudinal section with the welding tube shrunk and

Fig. 3 shows the subject of Fig. 1, in the left half with a filling opening and in the right half in the finished state.

The two double pipes 1 , each with an inner pipe Lei 2 for flowing media, a heat insulating foam 4 and an outer jacket tube 3 are next laid in a conventional manner butt to butt. The Lei pipes 2 can be made of a weldable plastic or a metallic material. Doppelrohrlei lines of this type are used for example in Fernheizleitun conditions. The jacket tubes 4 consist of a weldable plastic ver.

To connect the two conduits 2 , the ends of the double tubes 1 are first exposed by cutting or removing something from the telescopic tubes 3 and the foam 4 . The distance is chosen so that enough space remains between the exposed ends in order to be able to weld the two conduit pipes 2 to one another. Before laying the double tubes 1 via one of the double tubes 1 is pushed, a shrink tube 10 degrees. The weld seam is designated 5 . After welding the Lei pipes 2 is placed over the ends of the jacket tubes 3 each with heating wires 8 provided welding sleeve 7 , where the length of the welding sleeve 7 is chosen so that a gap 9 remains between the ends, as it is particularly left in Fig . 1 is shown. The gap 9 should be so large that when welding and softening the two welding sleeves 7 their heating wires 8 do not come into contact with safety. The welding sleeves 7 consist of a plastic which softens when the heating wires 8 are heated and which can be welded to both the jacket tubes 3 and the shrink tube 10 . The heating wires 8 are provided with connections for the electrical current. The shrink tube 10 is then pushed over the intermediate space or cavity 6 , with both welding sleeves 7 being covered. The shrink tube 10 is then heated and shrunk in a further step. By heating the welding sleeves 7 , a gas and watertight connection between the two jacket tubes 3 and the shrink tube 10 is then created (see also FIG. 2).

In order to be able to isolate the intermediate space 6 with a foam mass, a filling opening 12 is worked into each of the two intermediate spaces 9 , preferably drilled. The filling openings 12 lead, as shown in Fig. 3 on the left side, through the shrink tube 10 and the relevant casing tube 3 into a cavity extension 11 , which was incorporated in the initial exposure of the conduit 2 . Subsequently, the inter mediate space 6, including the two cavity extensions 11 , is foamed with a plastic mass which forms a heat-insulating foam after curing. The foam mass is expediently poured into one of the two filling openings 12 so that it flows over the center of the cavity to the other filling opening 12 . The optimal degree of filling is achieved when the foam mass emerges at both pipe ends.

After the filling of the cavity 6 and the cavity enlargements 11 , the fill openings are each grafted with a sweat 13, welded in a gastight and watertight manner and sealed. The welding plugs 13 are, as shown in FIG. 3, preferably conical before.

Reference list

1 double pipe
2 conduit
3 casing tube
4 foam
5 weld from 2
6 intermediate or cavity
7 welding sleeve
8 heating wires
9 space
10 shrink tube
11 cavity expansion
12 filling opening
13 welding plugs
14 vent

Claims (3)

1. A method for connecting double pipes with an internal pipe for flowing media, a heat-insulating foam and a jacket pipe, where at the ends of the double pipes to be connected, the ends of the pipe pipes are exposed and welded to each other around the ends of the jacket pipes welding sleeve provided with heating wires is placed, a shrink tube covering the space is pushed on and shrunk on, the ends of the jacket tubes and the shrink tube are welded together by heating the welding sleeve, the cavity surrounded by the shrink tube is filled with a heat-insulating foam through a filling opening in the shrink tube and the filling opening is closed ver, characterized in that a gap ( 9 ) is left between the ends of the welding sleeve ( 7 ) placed around the casing tube ( 3 ), a filling opening ( 12 ) in the region of the gap ( 9 ) through the Shrink tube ( 10 ) and the jacket tube ( 3 ) angeord net, which is filled up to the filling openings ( 12 ) expanded cavity ( 6 ) with the heat-insulating foam and the filling openings ( 12 ) with a sweat plug ( 13 ) gas and be sealed watertight. 2. The method according to claim 1, characterized in that when exposing the conduit ( 2 ) the foam ( 4 ) of the double tubes ( 1 ) is removed up to the area of the filling openings ( 12 ). 3. The method according to claim 2, characterized in that the filling openings ( 12 ) with a conical welding plug ( 13 ) closed and welded to who.