WO1998057094A1

WO1998057094A1 - Lining pipe and method of relining a pipeline

Info

Publication number: WO1998057094A1
Application number: PCT/SE1998/001136
Authority: WO
Inventors: Bygg Rolf Axelsson
Original assignee: Bygg Rolf Axelsson
Priority date: 1997-06-13
Filing date: 1998-06-12
Publication date: 1998-12-17
Also published as: SE509551C2; SE9702270D0; SE9702270L

Abstract

The invention relates to a hose-like lining pipe (1) for relining and consisting of at least two layers (2, 3, 4), of which an outer layer (2) is substantially fluidtight, whereby a dry binder is supplied between and/or in the layers (2, 3, 4). The invention also relates to a method of relining by means of such a relining pipe.

Description

Lining pipe and method of a pipeline

The present invention relates to a lining pipe and a method of attaching such a lining pipe to pipelines, such as water pipelines, sewers and the like normally being laid under ground, often below streets and roads, to recondition or renovate existing pipelines of the above mentioned kind by means of such lining pipes is called relining.

It constitutes a long known problem to be able to recondition, reline, existing pipelines without having to dig them up. A control of the condition of pipelines may be performed from ordinary manholes by means of for instance TV-cameras which are moved through the pipelines and by means of which the condition of the pipline in question may be seen on a viewing screen. Examinations may also be performed by means of mechanical detectors, by means of radioactive fluids which are allowed to flow through the pipes and the like. However, the examinations in themselves are no part of this invention.

In cases where the pipelines are in a relatively good condition, that is they maintain their normal round shape although for instance cracks are present, relining may be performed by pushing in so called "short pipes" from manholes and through the existing pipeline, and in this case said short pipes form a pipeline within the pipeline.

However, many times the existing pipelines are cracked or collapsed and the ends of the pipes are displaced radially from each other. Within certain limits the pipelines may in such cases be ground such that they are given substantially a constant diameter all along their length. Irrespective of the type of relining that is chosen, the existing pipelines must always be cleaned and freed from roots that have grown in and accumulations of junk and sediment, before performing the relining.

In order to avoid problems relating to lack of roundness, displaced edges at joints and cracks, and similar deficiencys of pipelines, it has recently become common to utilize flexible hoses which may be pulled through the existing pipelines or which may be extended therethrough in another manner. However, such hoses do not have any strength worth mentioning but may easily become compressed should the surrounding pipeline for instance collapse. For the purpose of providing a relining where also a strengthening of the existing pipeline is achieved, different methods and lining pipes have been developed. An example of such development is disclosed for instance in GB-A-2082285. According to said document a hose-like lining pipe is forced into an existing pipeline whilst a binder is simultaneously sprayed onto the inner wall of the existing pipeline, ahead of the lining pipe during its insertion, and fixes or binds the latter against the wall.

According to another method the hose-like lining pipe carries with it a binder binding the lining pipe to the inner wall of the existing pipeline. Said method is nowadays very common. However, it involves certain essential problems both regarding the technique and regarding the working environment.

The hose-like lining pipe consists of a layer of fluidtight material and one or more layers of feltlike material, which may be soaked with and may retain the binder. The binder thereby consists of a plastic, for instance epoxy. The plastics that may be used for the above puropose are on the one hand poisonous and allergy-causing and are on the other hand difficult to use. This means that the soaking of the feltlike material with the plastic must take place under such conditions that no worker may come to harm from the plastic, neither through contact with the plastic material in itself nor by contact with the gases emitted therefrom. Since the plastics that may be used for this purpose have relatively short curing time it would be desirable to be able to apply the plastic to the feltlike material in direct connection with the working site where the lining pipe is to be installed. For the above mentioned reasons the equipment for applying the plastic will be so complicated, expensive and bulky that it has to be stationary for reasons of conveniency.

Thus, the lining pipes are supplied with liquid plastic in a stationary equipment from which they will then be transported to the different sites where they are to be used. Such transports may take relatively long time in addition to the fact that it takes a certain time to perform the work. Thus, it may be a question of days between finishing the lining pipes and performing the laying of the pipes. In order to be able to maintain the plastic in a liquid condition for any ex- tended time, the lining pipes will have to be stored in refrigerated containers until they are laid. Even then the possible storagetime will be relatively restricted.

In connection with the laying of the pipes it is very difficult for the workers to avoid contact with the plastic and therefore allergy and other work-related injuries caused by the plastic are very common.

In view of the above discussed problems related to the technique used today, it is desirable to develop a lining pipe that may be stored in practically unlimited lengths during practically unlimited time, which is completely free from harmful agents and which may be put in order for laying at the site of laying by means of a simple and inexpensive apparatus. This object is achieved by means of the present invention, as it is defined in the enclosed patent claims which also specify that which particularly characterizes the invention.

The invention is described more closely below, in connection with the enclosed drawings, on which:

Fig.1 is a schematic, partially sectioned view of a portion of a lining pipe according to the invention,

Fig. 2 schematically illustrates how the laying of a conventional lining pipe is performed, and

Fig. 3 schematically illustrates how the laying of a lining pipe according to the invention is carried out.

The lining pipe 1 illustrated in Fig. 1 in the illustrated embodiment comprises an outer, fluidtight layer 2 and two inner layers 3 and 4 of felt-like or other fluid absorbing material. In this condition the lining pipe 1 is flexible and may be compared to a hose. The outer layer 2 may for instance consist of plastic, rubber or the like and is either a coating applied directly bnto the adjacent layer 2, or a separate unit. The inner felt-like layers 3 and 4, which on one hand are carriers of the binder and on the other hand also serve as reinforcement, are provided in a number depending upon the strength that is desirable to achieve for the lining pipe. These layers may consist of the same or different materials depending on the type of reinforcement that they are intended to be.

The lining pipe 1 is manufactured in a manner that is generally conventional. Thus, the different layers 2, 3, 4, which are initially in the shape of strips, are sewn together in a special machine to form tubes or hoses one outside the other and in continous lengths of several hundred meters. However, in accordance with the invention a pulverous binder, for instance cement, is applied between the different layers 2, 3, 4. This pulverous binder adheres to the surfaces of the layers and also penetrates layers.

The lining pipe manufactured in the described manner contains no poisonous, allergy-causing or otherwise environmentally harmful materials. As long as it is stored in a dry place it may be kept practically for ever without being damaged or without its properties deteriorating from the viewpoint of its intended use. Such a lining pipe according to the invention will be lighter than the conventional pipe containing plastic material, which means lowered transport costs. Said pipe will also be less expensive than the conventional one, since a binder such as cement is inexpensive, like water which is the fluid that is added, and not until immediately before the laying.

Fig. 2 illustrates how the laying of conventional lining pipes with plastic binder is performed. A feed pipe 6 is, by means of not illustrated means, mounted vertically in a manhole 5. The lower end 7 of the feed pipe 6 is angled towards the pipeline 8 to be relined. A lining pipe 1 is extended through the feed pipe 6 and its end 9 is turned inside out or turned back over the end 7 of the feed pipe 6, where it is sealingly and effectively fixed by means of for instance a strap. Through a hose 10 or other pipe water is supplied in the feed pipe 6, around the lining pipe 1. The height of the water column in the feed pipe 6 provides a pressure pressing against the portion 9 of the lining pipe 1 turned inside out and thereby causes the lining pipe 1 to move forwardly in the pipeline 8 to be relined, as is illustrated in the drawing. The pressure of the water also forces the lining pipe 1 outwardly towards the inner wall of the surrounding pipe- line, such that a secure binding is achieved between the inner wall of the pipeline 8 and the lining pipe. When it is desirable to speed up the curing of the plastic the water may be heated before use.

Fig. 3 schematically illustrates the laying of a lining pipe 1 according to the invention, which laying broadly corresponds to the laying illustrated in Fig. 2. A predetermined, calculated amount of water 1 1 is filled into the lining pipe 1, said amount primarily being determined by the length of the lining pipe, which may be several hundred meters, and by the amount of cement included therein. The bulge of the lining pipe 1 illustrated in Fig. 3 and caused by the amount of water 11, only has the purpose of elucidating the invention. In reality there occurs no bulging worth mentioning since the lining pipe 1 has very insignificant extensibility, if any. This supply of water is performed in connection with fixing the end 9 of the lining pipe 1 to the feed pipe 6. This fixing is preferably performed above ground, before lowering the feed pipe 6 into the manhole 5. At the same occasion the lining pipe 1 is threaded through a nip between a pair of rolls 12, where the spacing between the rolls is adjustable such that when the lining pipe 1 is pulled through the nip a certain amount of water will be able to accompany the lining pipe 1 and to wet the binder therein. This amount of water, which may pass, is then adapted to the amount of binder that is present between the layers 2, 3, 4 so that the correct mixing proportion is achieved. In certain cases the binder may contain ballast in the shape of for instance sand.

In order to improve the penetration of water into the binder between the layers of the lining pipe 1 in connection with the laying thereof, negative pressure or vacuum may also be applied to the lining pipe in the manner likewise indicated in Fig. 3. In this further developed embodiment the lining pipe 1 is positioned flat on a conveyor belt 13 between the rolls 12 and a supply, for instance the illustrated roll 14, of the lining pipe 1. In connection with laying the lining pipe 1 the outer layer 2 thereof is perforated at a position adjacent the end of the conveyor belt 13 being closest to the roll 14, whereby the perforations 15 are made in a suitable number corresponding to the width of the flat lining pipe 1, in a row transverse to the longitudinal direction of the lining pipe 1. Then, a corresponding number of suction cups 16, indicated in'Fig. 3, are brought into contact with the outer layer 2 of the lining pipe 1, over the perforations 15, whereupon a vacuum is applied to the suction cups by means of a suitable equipment that is not illustrated in the drawing.

By applying the vacuum the air is effectively sucked out from the lining pipe 1 and thereby the added water is likewise sucked back through the lining pipe, in a direction towards the suction cups and is thereby distributed evenly in the pipe 1. When the water approaches the position of the applied suction cups 16 the vacuum is disconnected therefrom and they are removed from the lining pipe 1. The perforations 15 are then sealed by vulcanisation of sealing pieces onto the pipe such that the outer layer 2 becomes fluidtight again. The lining pipe 1 is then inserted through the feed pipe 6 until the previously performed, now sealed perforations 15 are positioned at the opposite end of the conveyor belt 13, adjacent the rolls 12. Subsequently new perforations 15 are made at the first mentioned end of the conveyor belt, whereupon the cycle is repeated. The stepwise feeding of the lining pipe 1 for evacuating air therefrom is thereby preferably in the order of 10 meters.

In the described manner a very good distribution of the water in the lining pipe is achieved in connection with laying the same.

By then supplying water, as described, to the pocket formed by the lining pipe 1 where it is turned inside out such that the fluidtight layer 2 faces inwardly, the lining pipe 1 is first pushed downwardly and then into the existing pipeline to be relined. The binder then provides for a solid adhesion between the inner wall of the pipe line 8 and the lining pipe 1.

When comparing the previous system for laying lining pipes and the system according to the invention, it is obvious that the latter is environment-friendly and simple. Thus, it does not matter if workers come in contact with the binder, since it is not allergy-causing and since it does not emit any poisonous gases. If, for some reason, it is necessary to tear up a pipeline relined in accordance with the invention, the torn out material is harmless to the environment, which is not the case with the previous systems. The transports to the worksites may be performed with ordinary trucks and in larger amounts, since the fluid material to be added, to the binder does not have to be transported but is available at the worksite, thereby lowering the weight per unit of length of the lining pipe. This lowers the costs of the invention as compared to previous systems and results in less transport per unit of length which also spares the environment.

The invention has been described in connection with relining pipelines in the ground. However, it is obvious that the invention is also applicable within other areas, for instance with regard to reinforcing chimneys. In such a case the layer 2 initially being the outer layer may be loose such that after binding of the binder this layer may be removed by being pulled out. Since the strength of lining pipes according to the invention may be made very high, this may also be used for instance for strengthening tunnels, culverts and the like.

Claims

1. Hose-like lining pipe (1) for relining and consisting of at least two layers (2, 3, 4) of which an outer layer (2) is substantially fluidtight, characterized in that a dry binder is supplied between and/or in the layers (2, 3, 4).

2. Lining pipe according to claim 1, characterized in that the binder consists of cement.

3. A method of relining by laying hose-like lining pipes (1), which consist of at least two layers (2, 3, 4) which between and/or in themselves are provided with a binder, whereby the lining pipes, from a supply (14) are fed into an existing pipeline (8) through a feed pipe (6) and are turned inside out in the existing pipeline, characterized in that the lining pipe, to which is supplied a dry binder and which is provided with a substantially fluidtight outer layer (2), at a position before the feed pipe is supplied with an amount of water inside the lining pipe, whereupon the lining pipe is pulled through a nip between pairs of rolls (12) which nip allows a predetermined amount of water per unit of length to accompany the lining pipe, said amount of water wetting the dry binder.

4. A method according to claim 3, characterized in that in connection with laying the lining pipe an outer layer (2) thereof is perforated at a position at a distance before the pair of rolls (12), in that a vacuum is applied to the lining pipe (1) through the perforations, and during a limited time, and in that the perforations (15) are then sealed again, whereupon the lining pipe (1) is advanced a predetermined length and the sequence is repeated.

5. A method according to claim 4, characterized in that the lining pipe (1) between the supply (14) and the pair of rolls (12) is positioned flat on a conveyor belt (13) and is advanced with a distance of substantially 10 meters between each sequence of air evacuation.

6. A method according to claim 4 or 5, characterized in that suction cups (16) that are connected to a vacuum source are positioned over the perforations (15) for achieving the air evacuation from the lining pipe (1).