WO2001025677A1

WO2001025677A1 - Creation of a protective jacket during the laying of lines

Info

Publication number: WO2001025677A1
Application number: PCT/EP2000/009697
Authority: WO
Inventors: Franz-Josef Püttmann
Original assignee: Tracto-Technik Gmbh
Priority date: 1999-10-04
Filing date: 2000-10-04
Publication date: 2001-04-12
Also published as: AU7913400A; DE19947652C1

Abstract

The invention relates to a method and a device for creating a jacket around at least one line, whilst said line is pulled into the ground by a strip. The strip is shaped into a jacket which surrounds the line.

Description

"Protective jacket production when laying cables"

The invention relates to a method and a device for producing a protective jacket when laying and renewing underground lines.

When renewing old pipelines using the burst-lining method, the old pipe is continuously blown up with a bursting head and pressed into the surrounding earth, while a new pipe is drawn into the created channel behind the bursting head.

The neurotubes often consist of polyolefins, especially of polyethylene. Due to the chemical properties of the polyolefins, such pipes are suitable for carrying liquids or gaseous media, but also as protective lines for cables. In particular, pipes made of polyethylene have the considerable disadvantage that they can be damaged by sharp or pointed objects. If the soil relaxes after being pushed to the side during drilling, expansion or burst lining, the fragments of the old pipe or stones with the sharp and pointed edges are pressed into the new pipes. The fragments can be damaged particularly by high dynamic traffic loads on the floor above, or by pulsating flow cause damage to the pipe wall of the polyolefin pipe. This damage usually only occurs after a few years. This long-term damage is all the more significant that a gas high-pressure line, a drinking water line or the like can burst in the result.

Old pipe shards or stones can cause damage to the new pipes not only when the soil is pushed in. They can penetrate into the wall of the new pipe when the new pipe is pulled in, so that openings and cracks in the wall lead to leaks and leaks.

The German patent specification 41 24 825 describes pipes made from polyolefin which have a higher resistance to surface abrasion and at the same time have a higher ring strength and creep rupture strength. These improvements are achieved by using cross-linked polyethylene pipes, the outer skin of which has a layer of micro glass balls, the micro glass balls being arranged in a finely distributed manner in the polyolefin. Alternatively, the entire tube wall of the tube can consist of a mixture of polyolefin and micro glass balls. The mixture can be applied as a coating on a polyolefin tube provided with an aluminum jacket. The tube is also surrounded by a jacket for protection purposes.

The use of sheathed polyolefin pipes can limit the mechanical damage caused by old pipe shards or stones. However, since the jacket is not much harder than the actual core tube, there is no 100% protection against damage.

A further disadvantage of jacketed pipes is that the pipe consists of a large number of sections which are arranged with one another. Consequently, the jacket surrounding the pipe sections is not continuous, but rather interrupted at each of these joints. These points form weak points in the casing, since damage to the core tube due to sharp-edged fragments and stones can occur here.

The pipe joints, which are usually 6 to 12 meters long, are usually joined by butt welding using specially developed equipment. Attempts are sometimes made to cover the joints before moving in. In practice, however, this has not proven to be advantageous, since the weld seams represent a high resistance when pulling in with high earth friction.

A further disadvantage of jacketed pipes is that special clamping jaws are required for butt welding the pipes to be joined. In addition, the jacket in the area of the weld must be removed before butt welding.

If jacketed pipes are to be drawn into the ground, special attention should be paid to the liability of the jacket. On the one hand, the jacket must have a high level of adhesion to the core tube wall, so that it does not contract in the area of the joints when the tube is pulled in or pushes back like a wave Can be removed from the core tube again, for example by peeling. It is often necessary to remove the jacket from the core tube, e.g. if a supply line to a house connection must be retrofitted directly to the core pipe.

Another way to protect an underground pipe is to not pull the new pipe directly into the ground, but to lay a protective pipe beforehand. The actual line is then pulled or pushed into this protective tube. In addition to the annular space between the protective tube to be drawn in and the earth rich a second annulus, required between the protective tube and the actual conduit. Therefore, this process takes a lot of time and requires a relatively large hole.

Furthermore, this method requires a considerable amount of transport, since in addition to the actual pipes, the protective pipes also have to be transported to the place of use. This is particularly important because a very large volume has to be transported.

Instead of pulling in a jacketed pipe or a protective pipe, there is the option of pressing the generated annular space between the soil and the pipe to be pulled in. This can be done by pouring a hardening compound into the annular space before the drawing-in process. After curing, this mass creates the protective jacket. However, this method has the disadvantage that damage during retraction cannot be prevented.

A method for trenchless laying of a pipe in a protective pipe is known from German Offenlegungsschrift 198 08 478, in which a pilot hole is first drilled from a start to a target pit. A drill is then withdrawn from the target pit into the starting pit to widen the bore, to which both the product pipe to be laid and the protective pipe surrounding the pipe are fastened. Thus, the tube is drawn into the bore together with the protective tube surrounding it.

This method is cumbersome due to the large spatial extent of the protective tube, which can have a length of several meters, and requires large target pits. In addition, the transport to the place of use is complex and therefore expensive. German patent 36 03 238 describes a method for renewing sewage pipes, in which a hammer head drawn through the ground breaks an old pipe, presses the resulting fragments into the surrounding soil and pulls a new pipe into the old pipe immediately behind it. Connected to the hammer head are several metal strips which, together with the hammer head, are pulled through the old line in such a way that they come to rest within the fragments of the broken pipe. They cover the new pipe to be pulled in with an external reinforcement. In order to avoid that the strips move in the circumferential direction of the drawn-in tube during the pulling-in, the metal strips must be guided. This is done by a separate tape guide part at the insertion end of the line to be renewed, which has a ring with guides for the metal strips.

This procedure can reduce the risk of damage to the retracted new pipe by pushing back stones and fragments. However, damage is not reliably prevented since the outer reinforcement consists only of metal strips lying loosely on the pipe. The band guide part at the insertion end of the line to be renewed cannot reliably prevent the metal bands from moving. This is all the more true since there can be considerable distances between the insertion end and the front hammer head. In this way, old pipe shards or stones slide into the pipe between the metal strips.

The invention is therefore based on the object of providing a method and a device for producing a jacket when laying and renewing underground lines, which avoids the disadvantages mentioned above. In particular, a method is to be provided which enables the production of a reliable protective jacket at the place of use of the pipes to be drawn in. This object is achieved by a method according to claim 1. Advantageous further developments are in the subclaims.

The invention is based on the idea that a bursting tool is driven or pulled through the ground, which pulls a new line, preferably resting on a band, into the bore. However, the band can also lie above the pipe or laterally below. Preferably when entering the ground - or with an open construction in the empty trench - the band is reshaped and forced to enclose the new line as a jacket or to form a jacket of any cross-section.

This process can be used in various processes. In this way, the band can be reshaped during the bursting process and drawn into an old pipe or during drilling into the drilling route. It is also possible to pull the band into the widened opening during the widening. Alternatively, with the open design, it can be drawn into the empty trench or with re-lining into the old pipe. It can also be used when laying cables with a cable plow.

The method according to the invention is not limited to forming a protective jacket around individual pipes. Rather, tube bundles, cables and cable bundles can also be protected in this way. Any other cables connected to one another in a tensile manner, for example steel pipes or polyethylene pipes or PVC pipes and also short pipe modules, can be sheathed in this way, the sheath being able to fulfill a holding function instead of the protective function.

A particular advantage of the method according to the invention is that a long, continuous protective sheath, which completely surrounds the line over long distances, can be created which has no open or gaping joints or other connecting pieces over these distances. This is particularly advantageous for long lines. This end-to-end Sheathing also offers the advantage that, in addition to protecting the tube wall, the connecting pieces between the short tube modules, for example push-in sockets, which are preferably pulled in via a traction means such as a chain, rope or rod, are continuously protected but also held together. This additional protection and support makes it possible to use pipes of inferior quality, which otherwise cannot be used. This means considerable cost savings.

It can be particularly advantageous to have the jacket overlap at the axial ends in order to completely rule out the penetration of stones or broken glass. In special cases it is advantageous to connect the overlapping ends together. This can preferably be done by welding, for example by welding spots at a distance of 10 cm. Alternatively, a further reinforcement of the jacket formed from the band can be achieved if the edges of the band form a positive connection during the forming process. This connection can largely prevent the tube from opening.

The method according to the invention also has the advantage that the tensile force required for pulling in a tube can also be transmitted via the protective jacket. This reduces the tensile force acting on the pipe, which can fall below the permissible load for the pipe used. With the method according to the invention, pipes can therefore be used in trenchless laying technology, which would otherwise not be able to withstand the tensile load that arises.

The same applies to pipes - for example corrugated pipes or pipes with shoulders - whose outer surface increases the friction in the ground, so that the pipes as such are unsuitable for laying technology. Due to the However, the friction can be reduced so that such pipes can also be laid.

Another advantage of the method according to the invention is the reduction in the transport volume. This is especially the case when the tape rolls into a coil and rolls off the coil when the cable is laid at the leading end. This eliminates the need to transport large-volume protective sleeves or protective tubes. This has particular advantages, especially when drilling in a limited space, since the handling of large components is particularly difficult there and even partially. is impossible.

If the length of the line to be surrounded exceeds the length of the coil, the start of a new coil can be easily connected to the end of the old coil when it is pulled in. This connection is preferably done by spot welding. The forming of the band is not hindered, especially if the front band lies on the lower side of the connection and there is no protruding edge in the running direction.

In a preferred embodiment, the band is made of steel, into which stones, old pipe fragments or the like cannot penetrate. Furthermore, the skin friction when the tube is pulled in is reduced.

The skin friction can be reduced even further if the surface of the jacket is treated with friction-reducing agents, for example with hardening lubricants. For this, friction-reducing agents can be used, which are only applied on site at the construction site during the pulling in. The surface of a casing can also be designed in such a way that it has a minimized friction with respect to the surrounding earth or a surrounding liquid. For example, particularly low friction has aerodynamic surfaces. Advantageously, a split band can be used for the jacket directly in front of the coil. Slit strips are relatively inexpensive and are available in all strengths and widths.

In an advantageous embodiment, the supply of a drilling fluid, for example a bentonite suspension, and the removal of the cuttings through the annular space between the product line and the protective casing can take place. This has the advantage that a reduction in the amount of drilling fluid required is possible due to the limited washing space. In addition, the ecological problems of drilling suspension escaping into the surrounding soil along the drilling route are reduced.

The use of a jacket made of metal also has the advantage that the line can also be located in the ground afterwards, which is not possible with plastic pipes. This is done, for example, by inductive coupling.

The use of a metal sheath also has the advantage that live cables are always shielded. You can even ground the jacket and always use fuses to determine whether the cable is still completely insulated.

It is common to color-code cables or lines to distinguish them. In order to enable such a distinction to be made between the sheathed lines, the sheath can be colored to match the color of the line.

The strip is formed on a forming unit. In addition to a forming caliber, this preferably comprises a guide rail for the strip, which is arranged in front of the caliber in the direction of the insertion end. In a preferred embodiment, this guide rail can game consist of several shaping elements and can optionally be formed from roles. In the forming unit, the band is preferably under the line to be sheathed.

The caliber itself can be designed as a ring that surrounds the line in a form-fitting manner. It can be connected to the forming unit at one or more points. Any other cross-section of the caliber is possible according to this principle.

In an alternative embodiment, the caliber consists of rolls surrounding the line. This has the advantage of reducing the friction that occurs.

The method according to the invention is explained in more detail below with the aid of examples shown in the drawing. The drawing shows:

Fiq.1: a PE pipe when pulled into a pilot hole with a jacket from a coil;

Fiq.2: a bursting device when renewing an old line, while pulling in a line and during the sheathing process;

Fiq.3: a dynamic bursting device when renewing an old pipe and

Fig. 4: a schematic view of a forming unit.

When a PE pipe 1 is pulled through a pilot bore 2, a strip 3 is rolled off its coil 4 so that it rests on the PE pipe 1. The PE pipe 1 and the band 3 are connected to an expansion head 7, which pulls them behind them towards the end of the execution when the pilot hole is expanded and traversed. Both the PE pipe 1 and the band 3 is guided through a caliber 6 arranged in the forming unit 5. The forming unit 5 is located at the inlet opening of the bore. During the passage of the caliber 6, the band 3 is forced into the shape of the caliber 6 and at the same time forced to adapt to the PE pipe 1. The axial edges 8 and 9 of the band 3 are brought together and form the jacket 10.

If the method according to the invention is applied to a burst lining, a bursting head 12 with a bursting machine 11 is pulled on a winch rope 14 through an old pipe 13 from the insertion end to the winch assembly 15. The bursting head pulls the band 3 behind it, which rolls off the coil 4 at the insertion end. Here, too, the band 3 is forced through the caliber 6 so that it adapts to the PE pipe 1 and forms the jacket 10.

The fragments 17 of the blasted old pipe 13 are pushed laterally in the space between the PE pipe 1 and the ground during burst lining.

This process can also be combined with dynamic burst lining. The bursting sleeve 12 is pulled with the bursting machine 11 with the winch rope 14 via a deflection boom 16 towards the winch assembly 15. The line 1 is traversed by a supply line 26.

The forming unit 5 consists essentially of a frame 18, the caliber 6 and the guide elements 19, 20, 21, 22. The PE pipe 1 lies on the band 3. The caliber 6 is designed as a ring 25 and positively encloses the band 3 and the PE pipe 1, an annular gap 23 remaining between the PE pipe 1 enclosed by the band 3 and the caliber 6. The PE pipe 1 and the band 3 are connected to a tension head 24. In another embodiment, the strip 3 is formed by appropriately arranged rollers.

Claims

claims:

1. A method for producing a jacket around at least one line (1) when pulling into the ground with a band (3), characterized in that the band (3) is formed into a jacket (10) surrounding the line (1) when pulled becomes

2. The method according to claim 1, characterized in that the band (3) is forced by a forming caliber (6).

3. The method according to any one of claims 1 or 2, characterized in that the band (3) from a coil (4) unwinds.

4. The method according to any one of claims 1 to 3, characterized in that the friction of the belt (3) is reduced with friction-reducing means.

5. The method according to any one of claims 1 to 4, characterized in that the band (3) consists of metal.

6. The method according to any one of claims 1 to 5, characterized in that the band (3) consists of steel.

7. The method according to any one of claims 1 to 6, characterized in that the axial edges (8,9) of the strip (3) during forming for

Overlap.

8. The method according to any one of claims 1 to 7, characterized in that the axial edges (8,9) of the band (3) are positively connected or joined together.

9. The method according to any one of claims 1 to 8, characterized in that the line (1) is inserted into the soil when plowing with a cable plow.

10. The method according to any one of claims 1 to 8, characterized in that the line (1) is introduced into the soil during burst lining.

11. The method according to any one of claims 1 to 8, characterized in that the line (1) is laid in an open trench.

12. The method according to any one of claims 1 to 8, characterized in that a drilling suspension between the jacket (10) and the line (1) is guided.

13. The method according to claim 12, characterized by the removal of the cuttings between the casing (10) and the line (1).

14. A method for pulling a pipe into the ground, characterized in that the pipe is pulled into the ground on a jacket generated when pulling in.

15. forming unit (5) for producing a jacket (10) around a line (1), characterized by a caliber (6) surrounding the line (3) for shaping the jacket (10).

16. Forming unit (5) according to claim 15, characterized in that the caliber (6) from a line (1) surrounding ring (25) is formed with an annular gap (23).

17. Forming unit according to claim 15, characterized in that the caliber (6) is formed from rollers.

18. Forming unit according to one of claims 15 to 17, characterized by a guide (19, 20, 21, 22) of the strip.