DE8427320U1 - Socket in a through or branch connection for heat-insulated conduits - Google Patents

Description

Kabelmetal electro
Company with limited liability

84-37 / R

September 13, 1984

Socket in a through or branch connection for heat-insulated line pipes _: _ ^

The innovation relates to a socket in a through or branch connection for heat-insulated conduit pipes, which consist of an inner pipe that preferably carries a heated medium, preferably made of metal, one coaxially to this arranged outer tube made of plastic and one A layer arranged between the pipes consists of foamed plastic, in which the inner pipes, which have been freed from foam, are fluid-tight are connected to one another and the outer pipes are offset from the inner pipes and by a socket pipe seated on both outer pipes are connected and the space between the inner pipes and the socket pipe is subsequently filled with foam.

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From DE-GM 7811209 a through sleeve for heat-insulated pipes is known, in which a sleeve pipe made of plastic rests on the plastic outer sheaths of the interconnected pipes. In order to prevent moisture from penetrating the space between the socket pipe and the inner pipes, shrink tubes are provided that seal the annular gap between the socket pipe and the outer casing of the pipeline by the shrink tubes resting on both the socket pipe and the outer jacket. This type of waterproofing has a number of drawbacks in underground district heating pipes. It can happen, especially in the area of expansion pads, where an increased temperature can occur in the area of the shrink tubing, that when the pipeline is pushed in the ground, both the shrink tubing and the socket pipe are displaced in the longitudinal axial direction of the pipeline. Furthermore, it can happen that during so-called pressure foaming, the shrink tubes can be inflated by an increased pressure. This increased pressure arises from the fact that the polyurethane foam usually used for foaming the annular space between the inner pipe and the socket pipe tends to post-gas. The gases then pass through the annular gap between the socket pipe and the outer casing pipe of the pipeline and are then applied to the shrink tubing. If the shrink tubes are then heated, for example due to the pretensioning as a result of an increase in temperature of the inner tube , the dreaded expansion of the shrink tubes can occur.

The object of the innovation is to provide a socket in which the socket pipe is so firmly connected to the outer jacket of the pipeline that longitudinal displacement is not possible. In addition, the connection should be so tight that an ingress of moisture from the outside into the socket area is definitely avoided.

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This object is achieved in that the inner diameter of the socket pipe is at least 5 mm larger than the outer diameter of the Outer pipe and that the annular gap between the outer pipe and the Mufftin pipe with a plastic tape laid in the circumferential direction is filled, in which an electrically heatable resistance wire is located. When a power source is applied to the ends of the resistance wire, it heats up and heats the material of the Plastic tape so far that it becomes liquid. The adjoining areas of the socket pipe and the outer casing pipe also become so wide heated »that an intimate welding of the plastic tape with the adjacent layers is achieved. Since at the same time pressure from the outside on the connection point, i. H. in the field of plastic straps, is applied, the plastic material of the tape is pressed into any cavities that may be present. Used with particular advantage a socket pipe which is reduced in diameter at its ends, at least in the area of the plastic strips. In order to be able to quickly apply the heat required for the melting process, it has to be done Proven to be expedient to use a plastic tape in which a meandering resistance wire is embedded. One An optimal welded joint is obtained when the socket pipe, the plastic band and the outer pipe are made from the same material, preferably from Polyethylene. The socket pipe has a filling opening for the the foaming causing foam components, which after foaming through a plastic stopper by means of mirror welding is locked.

The innovation is explained in more detail on the basis of the exemplary embodiments shown schematically in FIGS.

To connect two pipes 1 and 2, each consisting of one Inner tube 3 made of steel, an outer tube 4 made of thermoplastic material and a thermal insulation located between the tubes 3 and 4 layer 5 are based on polyurethane, the outer pipe 4 and the heat insulation from each pipe end are first

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layer 5 deposited over a certain length. There is no weaning Of course, when the inner tubes protrude from the foam layer 5, as is customary with prefabricated lengths.

A socket pipe 6 is pushed over one of the line pipes 1 or 2 and the inner tubes 3, preferably connected to one another in a fluid-tight manner by a weld 7. If necessary, a message header or a Signaling wire pair, which is not shown, in the area of the through connection tied together. After the inner pipes 3 have been welded, the socket pipe 6 is pushed over the connection point. According to the The innovation is the inner diameter of the socket pipe 6 by at least 5 mm larger than the outer diameter of the outer pipe 4. In the annular gap

• A plastic band 8 is placed between the socket pipe 6 and the outer pipe 4

ι inserted, in which a resistance wire 9 is embedded. This

Plastic tape 8 can already be attached to the inner wall of the socket pipe 6 at the factory, for example by tempering, or it can be delivered to the construction site in prefabricated lengths. The prefabricated lengths are then expediently attached to the intended location on the outer tube 4. Tensioning devices (not shown) are then attached around the socket pipe 6 in the area of the plastic straps 8 and press the socket pipe 6 firmly onto the surface of the pipelines 1 and 2. Optionally, it is advantageous for at least 6 to heat the socket pipe in its end regions before the actual welding process to over 80 ⁰ C. Due to the heat-induced shrinkage of the socket pipe 6, a sufficiently high pressure is built up for the later welding of the socket pipe 6, the plastic strip 8 and the outer pipe 4 to one another. Then current is sent through the resistance wire, which after a short time brings the material of the plastic strip 8 to soften and melt, so that it completely fills the annular gap between the outer pipe 4 and the socket pipe 6 and with the inner wall of the socket pipe 6 and the outer wall of the Outer tube 4 welded. In order to obtain a flawless weld seam, it is advantageous that both the socket pipe 6, the plastic strip 8 and the outer pipe 4 are made of the same material, preferably

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wise polyethylene. After completion of the welds ί '

the clamping devices removed and passed through a in the socket pipe 6 i>

See filler opening 10 a foamable plastic mixture, preferred |

wise on the basis of polyurethane, filled, which the annulus § '

between the inner pipes 3 and the socket pipe 6 completely fills. jf,

When the rising foam appears at the filling opening 10, j |

the filling opening 10 by means of a plastic stopper

Mirror welding tightly sealed.

In the embodiment of Figure 2, a socket pipe 6 is with compared to the socket pipe according to Figure 1 used larger diameter, which in a suitable manner before the start of the welding process on the Plastic tape 8 is formed down. For this purpose, a clamping device that can be heated can preferably be used. Can also The end regions of the socket pipe 6 are formed by means of warm air.

In the figure 3 the plastic strip 8 is shown, in which the resistance wire 9 is embedded in a meandering shape.

Figure 4 shows an embodiment in which the socket pipe 6 on its ends is widened so that the plastic strips 8 in the Annular gap are inserted between the outer tube 4 and the widenings can.

The main advantage of the innovation is that the Plastic band 8, the socket pipe 6 is intimately welded to the outer pipe 4, so that moisture can penetrate into the annular space between the inner pipe 3 and the socket pipe 6 or the outer pipe 4 is avoided with certainty. The weld is so tight that a Moving the socket pipe 6 on the outer pipe 4 is impossible.

The socket according to the innovation can be particularly advantageous for pipes with Use an outside diameter of up to 450 mm.

Claims (5)

kahelmetal electro limited liability company 84-37 / R September 13, 1984 claims for protection 1. Sleeve in a through or branch connection for heat-insulated conduit pipes, which consist of an inner pipe carrying a preferably heated medium, preferably made of metal, an outer pipe made of plastic coaxially to this and a layer of foamed plastic arranged between the pipes, in which the inner pipes freed from foam are connected to one another in a fluid-tight manner and the outer pipes are set off from the inner pipes and connected by a socket pipe seated on both outer pipes and the space between the inner pipes and the socket pipe is subsequently filled with foam, characterized in that the inside diameter of the socket pipe (6 ) is at least 5 mm larger than the outer diameter of the outer pipe (4) and that the annular gap between the outer pipe (4) and the socket pipe (6) with (11LF320) II ') »• II ItI * »» » * "· 2 -I I a plastic strip (8) laid in the circumferential direction is filled, in which an electrically heatable resistance wire (9) is located is. 2. Sleeve according to claim 1, characterized in that the sleeve pipe (6) at its ends at least in the region of the plastic strips (8) in the Diameter is reduced. 3. Sleeve according to claim 1 or 2, characterized in that a meandering resistance wire (9) is embedded in the plastic strip (8). 4. sleeve according to one or more of claims 1 to 3, characterized in that the sleeve tube (6), the plastic strip (8) and the outer tube (4) of the same material, preferably polyethylene exist. 5. sleeve according to one or more of claims 1 to 4, characterized in that the sleeve tube (6) has a filling opening (10) for the foaming causing foam components which is closed by a plastic plug by means of mirror welding after foaming. (11LF3Z0)