DE19957334A1 - Replacing district heating lines without digging trenches involves removing old line sections at two holes, pulling out line or inner pipe between holes, pulling in new line or pipe between holes - Google Patents

Abstract

The method involves making a first opening hole in the heating line run, removing a first part of the old line, making a second hole, removing a second part of the old line, pulling out the old line or the inner heat transport pipe between the opening holes and pulling in a new line or inner pipe then insulating it or pulling in a new pipe with prefabricated insulation.

Description

Field of the Invention

The invention relates to a method for trenchless Exchange of district heating pipes with an insulating layer between an outer tube and at least one inner one Heat transfer pipe.

State of the art

Heat pipes have characteristic properties that make their handling for laying work complex. On the one hand, this stems from their at least three-layered Structure, consisting of at least one inner Heat transport pipe, some insulation Signal lines and an outer tube and the other from the necessary compensation points in the heat conduction system. Furthermore, district heating systems always require a preliminary and one return, thus two parallel lines. Because of of the at least three-layer pipeline structure and the The pipes are very thick-walled and require a lot of insulation usually very stiff.  

Old lines often have to be replaced by new district heating lines be replaced. The reasons for this are an aging population the line, a decrease in the insulation effect, so associated heat loss or none or defective Signal cable, or corrosion. The usual ones at the moment Exchange work is very complex and costly because extra wide trenches have to be dug and long, there are traffic opening obstacles. About that In addition, the recycling effort for the pipes is very high and a correct pipe bed renewal with a high Time involved. For all the reasons mentioned, it is Acceptance for such measures in the population right low. Since district heating pipes age relatively quickly, they often need to be renewed, which is usually the case has so far been a complete exchange.

Because of the general economic conditions Liberalization of the energy market is another Expansion of district heating systems can hardly be expected anymore because Transport and distribution of district heating partly more than is twice as expensive as with other energy sources.

Presentation of the invention

The invention has for its object a method for Exchange district heating pipes to propose that with can be carried out as little effort as possible.

This task is accomplished by a process with the characteristics of Claim 1 solved.

The invention is based on the idea of a method for to propose trenchless exchange of district heating pipes. A trenchless exchange of district heating pipes, similar to that Replacement of power cables, water or gas pipes was done So far not carried out because the material differences in District heating pipe are too large. The method according to the invention  involves creating first and second opening pits in the Course of the district heating pipe, being between the two Opening pits of the section to be renovated is located. In the Opening pits each become a piece of the old one District heating line separated and the old district heating line or the inner heat transfer pipe of the old district heating pipe pulled out and a new district heating line or a new one inner heat transfer pipe retracted. By this measure only need to create opening pits at larger intervals be, the distance between the opening pits according to the required and to be achieved traction at Pulling out the old district heating pipe measured.

Preferred embodiments are defined by the remaining claims characterized.

According to a preferred embodiment of the invention the step of pulling out the old district heating pipe and pulling in the new district heating line at the same time by the new district heating pipe with the old district heating pipe is coupled. This measure has the advantage that a Work step can be saved and the process for Replacing the district heating pipe can be done faster can. However, the train resistance increases Pull out the old district heating pipe so that this is one Influence on the selected distance between the Can have opening pits. Another advantage of this Measure is that if there is an unstable surrounding Soil structure does not pose the risk that after Pulling out the old district heating pipe the drilling walls collapse and pulling in a new district heating pipe is difficult.

In a preferred embodiment, the method comprises continue to pull out the old district heating pipe Step of coupling the old district heating line in the second opening pit with a pulling head. In this way  can be a carriage drill, as in the Horizontal drilling technology is used to pull out the use old district heating pipe.

In a preferred embodiment, the method comprises continue before pulling out the inner Heat transfer pipe of the old district heating line the step the passage of the insulating layer between the outer tube and the inner heat transfer pipe with a Pilot drilling device for producing a pilot borehole. This alternative method serves only the inner Exchange heat transfer tube while the outer tube in the Floor remains. Because through the surrounding insulating layer Bond between the inner heat pipe and the Outer tube exists, can be thinned through and partial or complete removal of the insulating layer Loosen inner heat transfer pipe so that this is easy can be pulled out.

According to a preferred embodiment, after Passing through the insulating layer through a cutting device pulled the pilot hole. This cutter that attached to the drill pipe instead of the pilot drill head can be used in a single step entire ring-shaped insulation layer if possible largely remove.

According to a preferred alternative embodiment, the Pilot drilling device wing cutter or a ring collar who has high pressure water jets or heaters. According to this alternative, the pilot drill head is not removed from the Drill rods released and one instead of the pilot drill head Cutting device attached, but has the Pilot drilling device already suitable facilities to the To remove the insulating layer. This can be wing cutters or but also be a ring wreath, which in turn either with High pressure water nozzles or heating devices is equipped, so  that the insulating layer is removed with high-pressure cutting jets or through the operation of the heating devices can be annealed or flamed out.

According to a preferred embodiment of the invention the process continues the step of removing the remaining insulation after pulling out the Heat transfer pipe. This step serves to Available volumes within the outer tube free of To make insulation material, so a new heat pipe with a surrounding insulating layer applied to it can be pulled back into the outer tube.

According to a preferred embodiment, when pulling in a centering device of the new heat transfer pipe used. This alternative method comes in particular then used when the new heat transfer pipe is not yet is surrounded by an insulating layer, but the Insulating layer only in a subsequent step should be introduced. In this case it is important that the heat transfer pipe in all directions with a is surrounded essentially the same thick insulating layer in order to keep the total heat loss as low as possible.

The old one is preferably pulled out Heat transport pipe with an internal pulling device, preferably spreading claws or compressed air packers. To this Way, the heat transfer pipe can be as possible pull out gently, because this is from a Puller transferred to the heat transfer pipe Distribute loads over a larger area and thus damage to the heat transfer pipe with it resulting difficulty in pulling out the tube do not occur.

The first opening pit and / or the second are preferably Opening pit in the area of a compensation device or  a side branch arranged. Must in these areas a pit will be created anyway, so the choice of individual renovation sections with due regard to the opening pits must be provided should. However, there is a large gap between two neighboring compensation devices conceivable that individual renovation sections of one District heating pipe located between opening pits not in the area of a compensation device or of a side branch.

Ways of Carrying Out the Invention

In the following, purely by way of example, using several Examples of the trenchless exchange method according to the invention and corresponding devices to be used for this purpose are explained in more detail.

In the following the description of the Variants between rigid and flexible District heating pipes can be distinguished. The Exchange opportunities are due to the clearer Structure, easier with rigid district heating pipes than with the flexible systems.

Most rigid district heating pipes have one insulated tubular steel outer jacket as well as one or two in Heat transfer tubes arranged inside the outer tube, the are embedded in the outer tube with an insulating layer.

In the simplest case of replacement, one is up to 15 meters long opening pit a piece of the old district heating pipe separated and the new line to be pulled in are the same Outside diameter and the same outer construction on the Separation cut welded on. All of them in more detail below exchange tasks are generally sought, District heating pipes through new pipes with the same  Flow cross-section to replace. In another Opening pit that is as economical as possible to the first opening pit and preferably at or next to a compensator or a compensation sheet is arranged, in turn a piece from the Old district heating pipe separated. The second opening serves for welding a drawing head to the old district heating pipe. This pulling head comes with a strong drill pipe or the Mounted to a horizontal drilling rig related on the tractive force to be achieved, the Pull out the old district heating pipe between the openings and the welded new district heating pipe from the first Opening pit to the second opening pit at the same time move in. To the large pulling forces required for this can perform the horizontal drilling machine during the drawing process drive backwards and possibly by another connected Towing vehicle are supported.

After driving through the line between the first Opening pit and the second opening pit can Old district heating pipe by a simple cut from the connection welding to the now pulled in new one District heating pipe to be separated.

As already explained above, the opening pits expediently with the compensators or side branches Household connections and the like arranged so that this Openings at the same time as assembly or exchange pits for the Compensators and side branches can be used.

Using the procedure for exchanging rigid district heating pipes will therefore be the entire District heating pipe replaced. Should the old one District heating pipe, however, not in accordance with the building regulations be sanded, but embedded with cohesive soil has usually been due to the very high Stiction does not pull out the outer tube.  

In this case, a different workflow prefers. With a horizontal drilling machine is between the in this case smaller opening pits and the ones here separated sections of the old district heating pipe Pilot hole in the insulating jacket of the old district heating pipe performed. Here, the smallest possible drill head used with different functional devices can be coupled, or this Functional devices already integrated. aim this measure is the crawl and partial or completely circumferential removal of the insulating layer, which in usually consists of PUR foam and between the inner Heat transfer tube and the outer tube is arranged. The The outer tube should remain consciously and unchanged in the ground. The insulating layer should at least be removed all around be that a complete pull out of the Heat transfer pipe is possible. In most Use cases exist only for this transport pipe real need for replacement, since the heat transfer pipe experiences the highest loads and strongest leaks. The plastic jacket pipe is a composite system that consists of the inner heat transfer pipe (steel pipe), insulation (e.g. PUR foam) and the one that acts as a protective jacket Outer pipe (e.g. PE pipe) exists. Damage to a of these components always leads to the impairment of Heat transfer and ultimately damage or Destruction of the district heating pipe.

The process of removing the insulating layer can occur different ways are done.

So with a thin pilot drill head and a corresponding drill pipe the insulation layer in Longitudinal direction on the entire exchange route between the pierced the first opening pit and the second opening pit become. After piercing it becomes a sharp one  Cutting device with a wide surrounding heat transfer pipe a beveled head shape backwards through the pilot hole drawn, the insulation lengthways circular cut open and the heat transfer pipe detached from the composite becomes. The heat transfer pipe can then after coupling a corresponding pulling head connected by a Drill pipe pulled out from a horizontal drilling rig become. The remaining insulation can be covered with a corresponding device, which is also by a Horizontal drill pipe is guided, annealed, flamed out, peeled out, milled out or z. B. cut out using rotating high pressure water jets become. If the ring cross-section is even, a the remaining outer cross-section remains in the bottom, the one on the outer tube is present. Then the new one with a pulling device Heat transport pipe with surrounding insulation layer pulled in. The pulling device is preferably monitored for tractive force and it a leading centering device can be used, so that the new heat transfer pipe adapted to the cross-section to be filled in the middle of the outer tube is located. In this way, the most important Functional part of a district heating pipe completely trenchless be replaced.

As an alternative to the procedure described above, the Pilot boring head itself with a suitable device be provided to separate the insulation. So he can Pilot boring head with curved wing cutters or one around ring cutter running around the heat transfer pipe be equipped so that through without rotation of the drilling rig the mere advance with the drill pipe already Isolation process in a forward motion can be executed. In a subsequent pulling process then becomes the inner tube in the manner described above removed, the remaining insulation may be removed and the new heat transfer pipe with a pulling device moved in.  

After another alternative procedure to the above described procedure, the pilot drill head can a have the ring around the heat transfer tube, the one with high pressure water jets and one in between arranged sharp teeth is provided, which is suitable to destroy, crush and remove the insulation. The old heat transfer pipe serves as Jacking pipe around which the ring collar Provided pilot drill head can rotate with rods.

According to a further alternative implementation of the The pilot drill head can have an annular ring, which is heatable, or open burner for dispensing Owns flames. This allows the insulation in Direction of burned out, burned out or be sublimed out. The corresponding pilot drill head will with this alternative process performed without rotation and the drill pipe has depending on the embodiment accompanying power cable for the operation of electrically heated Heating devices, or a hollow tube for Fuel gas supply on.

The two basic procedural alternatives of the whole Exchange of the old district heating pipe as well as only that Partial exchange of the heat transfer pipe Old district heating pipe can also be exchanged use flexible district heating pipes. However, at flexible district heating pipes the process of Insulation drilling, insulation cutting and the Removing the insulation layer is much more difficult than with rigid tubes. The advantage of the trenchless described Exchange process related to flexible District heating pipes is, however, that the size of the Opening pits in the street space can be made smaller.  

Flexible district heating pipes are mostly only used for cost reasons smaller dimensions used than rigid Plastic jacket pipes. From the smaller to the essential smaller diameter compared to rigid pipes follows, that the handling space in the isolation with flexible District heating pipes is much less. The Heat transfer pipe is either a metallic corrugated pipe or designed as a plastic tube. As Plastic materials are mostly polyethylene, polypropylene or cross-linked polyethylene. So they are Heat transport pipes neither very tensile, nor thermally high trained resilient. The outer tube also mostly consists of flexible plastic (polypropylene, polyethylene, cross-linked Polyethylene) and should also be neither mechanical nor be subjected to high thermal stress.

Nevertheless, there are several options when replacing flexible district heating pipes:
First of all, a complete exchange of the district heating pipe is possible, but due to the lower tensile strength, the exchange distances have to be kept shorter than with steel outer pipes. Polyethylene outer tubes or polypropylene outer tubes can also be welded with a suitable welding mirror apparatus and thus connected with tensile strength. Thus, the exchange process for the complete replacement of flexible district heating pipes is carried out analogously to the procedure described above for the complete exchange with rigid district heating pipes.

Alternatively, it is also conceivable to use only the heat transfer tube including the insulating layer or large parts of the insulating layer exchange. A pilot hole is also used here, over which the insulation is passed in the longitudinal direction. In the retreat of the pilot drill string, a Ring ring cutter, which is based on the outer tube and close applied to this, used in the manner described above  and destroy and remove the insulation layer. With this alternative method too, a High-pressure water ring nozzles provided for Get involved.

A cut through the insulation layer at forward driving is waiving Rotation also with a guided on the outer tube mechanical or hydromechanical ring cutter possible if the radii of curvature in the installation route of the flexible district heating pipe are not too tight. The Orientation on the outer tube is advantageous because the Heat transfer pipe, as explained above, as metallic corrugated pipe can be executed, and thus not suitable for guiding a ring ring. Should on the other hand, the outer tube can be designed as a corrugated tube, so is the use of a guided on the smooth inner tube Ring ring cutter advantageous.

The heat transfer pipe to be removed can be used a plastic pipe using an internal pulling device can be removed in the form of expanding claws. The Internal pulling device is preferably used with the drill pipe connected to a horizontal drilling rig so that a sufficient high pulling force for pulling out the heat transport pipe Available. In the case of a corrugated pipe material in the Old district heating pipeline is a cascading introduction of Compressed air packers are recommended as the compressed air Packer in a positive manner to the internal geometry adapt the corrugated pipe material and thus high tensile forces can transmit. Nevertheless, the corrugated pipe material can just pull clearly deformed. Because of yourself subsequent disposal of the withdrawn Heat transfer pipe, however, is not from Matter. One can also pull in new corrugated pipe material Packer chain used on an internal pull rod become. Here, however, is a permanent one  Tractive force monitoring during the pull-in process is required to ensure that Corrugated pipe material of the new heat transport pipe not in improperly deform or damage.

The process alternatives described above in which only the inner heat transfer pipe is replaced, generally represent the preferred variant. This applies especially for plastic jacket pipelines, which in Delivery lengths of 6 m and 12 m can be laid. The Connections of two line ends of the Plastic jacketed pipes are made via sleeves, which due to the assembly technology a little have a larger diameter than the outer tube jacket. This makes it difficult to pull out the entire old district heating pipe, especially for soils with a high density.

In general, when replacing the old heat transfer pipe is too note that the flow cross-section is usually the same must stay. In exceptional cases, however, can also be flexible District heating pipes in an existing outer pipe Old district heating pipe are pulled. However, consciously accepted that the flow cross-section of the heat transfer pipe reduced.

The method according to the invention can be used for the first time Replace district heating pipes in a cost-effective manner, by proposing a trenchless process.

Claims (12)

1. A method for the trenchless exchange of district heating pipes with an insulating layer between an outer pipe and at least one inner heat transport pipe, comprising the steps:

• a) creating a first opening pit in the course of the district heating pipe;
• b) cutting out a first piece of the old district heating pipe;
• c) creating a second opening pit in the course of the district heating pipe;
• d) cutting out a second piece of the old district heating pipe;
• e) pulling out the old district heating line or the inner heat transport pipe of the district heating line in the section between the first opening pit and the second opening pit; and
• f) pulling in a new district heating pipe or a new inner heat transport pipe of the district heating pipe with subsequent insulation or a new inner heat transport pipe with prefabricated insulation in the section between the first and second opening pit.

2. The method of claim 1, wherein step (e) of Pulling out the old district heating line and the Pulling in the new district heating pipe at the same time done by the new district heating pipe with the old one District heating pipe is coupled. 3. The method of claim 2, further comprising before the step of pulling out the old district heating pipe:
Coupling the old district heating pipe in the first opening pit with a pulling head. 4. The method of claim 1, further comprising the step before pulling out the inner heat transport pipe of the old district heating pipe:
Passing through the insulating layer between the outer tube and the inner heat transport tube with a pilot drilling device for producing a pilot borehole. 5. The method according to claim 4, characterized in that after passing through the insulating layer Cutting device is pulled through the pilot hole. 6. The method according to claim 4, characterized in that the pilot drilling device or a wing cutter Has ring ring, the water high pressure nozzles or Has heaters. 7. The method according to any one of claims 4 to 6, further comprising the step:
Remove the remaining insulation after pulling out the heat transfer pipe. 8. The method according to any one of claims 1, 4 to 7, characterized in that when pulling in the new heat transfer pipe Centering device is used. 9. The method according to any one of claims 1, 4 to 8, characterized in that pulling out the old heat pipe with an internal pulling device, preferably expanding claws or compressed air packers.   10. The method according to any one of the preceding claims, characterized in that the first opening pit and / or the second Opening pit in the area of a compensation device or a side branch is arranged. 11. The method according to any one of the preceding claims, characterized in that only part of the old insulation, however geometrically longitudinal axis ring-shaped, is separated and a new inner tube with a fitting partial insulation is drawn in. 13. The method according to any one of claims 1, 4 to 7, characterized in that when pulling in the new heat transfer pipe Tensile force measuring device is used.