FI98157C - Method for lining flues and pipelines - Google Patents

Description

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METHOD OF LINING FLUCKS AND PIPING

The invention relates to a method for lining various flues and pipelines with a layer of suitable material for repairing cracks or other defects in them for various reasons.

5 It is well known to repair variously damaged flues and pipelines internally without having to “open” or dig them out. This is especially the case when the flue or piping is installed in a place where it is difficult to completely replace it. This is the case, for example, with air-conditioning ducts related to underground sewers or house structures.

The repair is carried out by known methods, for example by inserting a new pipe into the old pipe or flue. The space between the old and the new pipe can still be filled with a suitable injectable mass on the one hand to improve the anchoring of the new pipe and on the other hand to provide additional rigidity to the new pipe.

It is also known to use a resin-impregnated fiber “woven” sock for lining, which after lining is cured to its final strength 20 and pressed against the wall of the old pipe by means of vapor pressure.

A third known principle is to spray a coating on the inner surface of an old pipe or flue, which is often a substance corresponding to the material of the old pipe.

All of the above methods have significant drawbacks which can be remedied by the method of the invention.

When using a liner pipe, a contradiction arises in that, on the other hand, the new pipe must be flexible so that it is possible to pass it in general in a flue or pipe which may have bends and possibly also a limited inlet space. The latter situation is especially true in the lining of underground sewer pipelines, in which case the lining has to be done through wells in the sewer line with a bending radius of even less than a meter.

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On the other hand, the pipe must be rigid enough in use to withstand, for example, ground pressure in the drain pipe and vacuum in the air conditioning pipe. When this is not the case, the intermediate space has to be injected with the filling mass to increase the stiffness, which causes additional costs and reduces the flow capacity due to the reduced inner diameter.

When using a resin-curable nonwoven tube or spray coating after installation, there is a problem in that the new surface follows the inner surface of the old tube, making it impossible to repair collapses and larger holes.

An additional problem is that the known liners are made of plastic, which often causes a fire safety restriction. This is especially the case for ventilation ducts in buildings; fire safety standards in many cases outright prevent the use of these methods.

The aforementioned fire safety problem is solved in the method according to GB application 2212605, in which the liner is used only as a mold to provide a new coating by injecting a curable mass between the mold tube and the old tube and removing the mold tube after drying. The problem then, however, is the removal of the mold tube; the longer and more tortuous the uniformly lined pipe or flue, the more difficult it is to remove the mold pipe.

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The method according to the invention has succeeded in eliminating all the above-mentioned drawbacks and has provided a simple and safe way of lining the widest possible range of flues and pipelines.

30 The starting point of the method is the same as in GB application 2212605, i.e. it is most advantageous from the point of view of adhesion, fire safety and strength to use the same type of material as the lining material from which the flue or pipe itself is made. In this case, mainly mineral-based materials such as concrete, brick or the like are involved.

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As previously stated, spraying such a substance onto the surface of an old flue or pipe does not correct collapses or other major discontinuities.

Thus, the method according to the new invention also uses a mold pipe which is lined inside an old flue or pipe and then injected into the intermediate space created by the liner, using pressure if necessary, whereby all free space between the pipes is filled, including collapses and other discontinuities.

5 However, once the mass has dried, the mold tube is not "pulled out" as in GB application, but is helically dismantled with the aid of a helical structure of the mold tube so that disassembly takes place along the weakest point of the mold tube.

10 While the unloading spiral is still being pulled out through the end of the mold tube which unloads last, the unloading can be effected without damaging the surface of the new liner, since the unloading spiral is in constant contact with the inner surface of the unloaded mold tube.

The invention will be described in more detail below with reference to the accompanying drawings, in which Figure 1 shows a cross-section of a profile from which a pipe is made, Figure 2 shows a partially sectioned mold pipe, Figure 3 shows a flue with typical flue defects and Figure 4 shows a flue with a mold pipe according to the invention.

In order to test the new method in practice, a profile according to Figure 1 was first made of thermoplastic polyurethane (TPU), which consists of the plastic part itself (1) and a steel wire reinforcement (2). The profile was shaped to form a short thinner base (3).

In the next step, the above-mentioned profile was spirally formed into a mold tube according to Fig. 2 with an outer diameter of 200 mm. The tubes were formed by spiral sealing with heat and pressure so that the joint 30 was formed at (1).

A square chimney according to Figure 3 was made of brick, with a cross-sectional area of 250x250 mm, on the surface of which typical chimney defects were intentionally made, for example leaving some bricks too small.

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Said flue was then lined with the above-mentioned mold tube as shown in Fig. 4. The concentration of the pipe in the flue was ensured by means of springs (1) so that the direction of the springs was opposite to the direction of lining. The positions of the springs had been measured in advance and fixed to the measured positions 40 before lining.

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In the next step, the space between the flue and the lined molded pipe at the lower end of the flue was closed using a pressure-expanding tubular bellows (2).

5 The space between the chimney and the mold pipe was then filled by injecting foam concrete with an average stone size of 3 mm and a density of about 600 kg / m3. The injection was made from the upper end of the flue.

After the foam concrete had hardened, the mold pipe was dismantled through the upper end, starting with 10 discharges from the lower end of the mold pipe.

The resulting concrete liner was finally photographed by driving a video camera through the chimney. The result was found to meet the requirements.

Next, the above experiment was repeated with the difference that before the mold tube was lined, its outer surface was treated with silicone oil. At that time, it was found that the force required to disassemble the mold tube was reduced by almost half.

In the third experiment, the corresponding formwork pipe was laid in an underground horizontal concrete drain with an inner diameter of 20,240 mm. The plating was done through a 800 mm diameter sewer.

The tubes were centered by springs and the intermediate space was injected with foam concrete, after which the mold tube was removed by spiral disassembly. Based on the video recordings, the result was found to be good.

The invention is characterized by what is set forth in claim 1, but its details, such as the materials used and the installation techniques, may vary widely within the scope of the claims.

Claims (3)

A method for lining various pipelines and flues, in which a flexible mold pipe made of a suitable material is inserted into an old flue or pipe, the space is filled with a curable mass and said mold pipe is removed after the mass has hardened, characterized in that the mold pipe is removed by spiral disassembly. Method according to Claim 1, characterized in that the surface of said molded pipe is treated with a release-promoting agent before installation. A method according to claim 1, characterized in that said mold tube is made of thermoplastic and spirally reinforced with a metal wire. B 98157