The present invention relates to a seal according to the preamble to claim 1, and a method of providing it.

Lining pipelines, so-called "relining", is a rapid and economical method of repairing such as leaking sewage or water pipes inthe ground.

An attractive relining method is to use relatively short lining tubes or liners, which have a length such that they can be taken down into an access chamber, for being connected together there, e.g. for insertion into a leaking sewage pipe which is to be repaired. In such a case, the ends of the liner are implemented such that the mentioned connection is enabled. The liners are usually made from a plastics material, but other materials are also conceivable, of course.

When the mentioned relining method is used, there are problems with achieving an effective seal between liner and surrounding pipe at the ends of a liner pipeline. This seal must be effective, so that the liquid which is to flow in the liner pipeline does not flow outside it and to a point of leakage.In addition, the seal must be made so that liquid flow is disturbed to the least possible extent on entry inτo and exit from the liner pipeline.

The seal shall also prevent such as extraneous ground or leakage water from undesirably ccming into the liner.

The object of the present invention is thus to provide an extremely effective seal that solves the above-mentioned problems, and this ob¬ ject is achieved by the seal having been given the characterizing fea¬ tures disclosed in the claims. Tne inventive seal can thus be used, e.g. at the ends of a connected-together string of liners, i.e. the free ends of the end liners in a string of liners are provided with the inventive seal. The latter is so effective that there are no problems in stopping off the liner where a service pipe connects to the outer pipe, a very

effective seal being made with the aid of the inventive seal on either side of the service pipe connection, resulting in that it is not neces¬ sary to excavate down to the service pipeconnection and renew it, or with the aid of some complicated type of remote operation take up, and arrange a new connection between the service pipe and the liner.

__he inventive seal is very advantageous, since it allows injecting fil¬ ler material into the seal when the liner provided with the seal is in place in the outer pipe, the seal effectively guiding the filler mater- ial so that it flows round the entire circumference of the liner and thus effectively locates the position of the liner in relation to the outer pipe surrounding it. The seal also has a deflecting lip, which has. a very positive effect on the entry and exit conditions of the liquid flowing in the liner pipeline.

Embodiment examples of the invention will now be described in more de¬ tail in the following, and with reference to the accαrpanying drawings, where Figure 1 is a longitudinal section of an end portion of a liner provided with the inventive seal, the seal being in an inactivated ϊnit- ial state; Figure 2 is a partial view according to the arrow II in Fig¬ ure 1; Figure 3 is a schematic, longitudinal section illustrating the inventive seal, where the proportions thereof have been somewhat altered for the purpose of clarity; Figure 4 is a longitudinal section showing a portion of a liner provided-with aninventive seal, the seal having been compressed into an inactive state by a tool; and Figure 5 is a lon- gi-tudinal section illustrating the inventive seal in an active state when it is expanded into engagement against an exterior pipe surround¬ ing the liner.

Figure 1 illustrates an end portion of a liner 1, made from such as plastics material. The liner 1 has at one end a sleeve-shaped seal 2 on its outside for the purpose of providing sealing engagement between the liner and a surrounding pipe 3. The inventive seal 2, e.g. made from rubber material, in an inactivated state has at one end a conical deflecting lip 10. The lip 10 is rela¬ tively -thick-walled and to advantage it has a waist 11 for obtaining the desired resiliency, the waist also positively affecting the ability of the lip to adjust itself into good engagement against the outer pipe.

The top lip has an end surface for sealing engagement against a sur- rounding pipe 3.

Suitably, there is also a shoulder surface 13 on the deflecting lip 10, intended to engage against the end surface of the liner 1 so that it can be visually ascertained that the seal is correctly mounted on the liner. This arrangement also improves the liquid flow through the liner, as well as improving this flow by the smoother junction between lip and liner.

The sleeve-shaped seal 2 has a cavity 14 defined by an inner wall 15 and an outer wall 16. The outer wall 16 has a fold 17 to enable desired expansion of the cavity 14.

The seal 2 further has an annular lip 18 inside the cavity 14, this lip covering a hole 19 arranged in the inner wall 15, the inner annular lip 18 functioning as a non-return valve when injecting filler in the cavity 14, since it can momentarily yield at its free end 20 from sealing en¬ gagement against the outer surface of the inner wall 15.

At its end remote from the deflecting lip the seal 2 has an outer annu- lar lip 21, which can be regarded as constituting an extension of the inner wall 15 since the lip 21, as well as the inner wall 15 engage tightly against the outer surface of a liner 1. The exterior lip 21 is intended to function as a non-return valve in connection with the poss¬ ible injection of filler in an area behind the seal 2, since the free end 22 of the lip 21 can resiliently move away from its tight engagement against the liner 1 under the action of a stream of filler.

For further improving the fixation of the sleeve-shaped seal 2 against a liner 1, it is preferably provided with one or more inwardly directed circumferential ribs 23 engaging in recesses 40 complementary to the ribs in the outer surface of the liner.

It will be understood that the diameter of the seal 2 is selected such that the seal tigfttly engages against the outer surface of the liner 1 after it has been fitted.

As will be seen, e.g. from Figure 1, the liner 1 is-provided with a hole 41 for injecting filler, the seal 2 being fitted to the liner so that ^• the hole 19 in the seal coincides with the hole 41 in the liner. It should be mentioned here that it is suitable to form the hole 19 in the rubber seal greater than the hole 41 in the liner wall to avoid injected filler coning between the seal and the tube instead of inside the cavity 14 of ^* the seal. In addition, it is suitable to make the hole 19 in the seal elongate, as will be seen from Figure 2, thereby to reduce the tol¬ erance requirement of the angular position of the seal in relation to the liner when fitting the seal to the liner.

It is of great importance that the seal 2 is evacuated : rom air before injecting filler, as illustrated in Figures 1 and 4, since air possibly enclosed in the cavity 14 after completed injection of filler can leak out from the seal after a time and thereby jeopardise the long-time function of the seal. The manufacturing process -used in manufacturing the seal ensures that it will be practically exhausted from air.

The liner 1 suitably has at the part of it carrying the seal a lesser outer diameter than its maximum outer diameter, resulting in that the seal before supplying filler is so compressible that a protective means 50 can be mounted over the seal for temporarily keeping the seal in a compressed state in conjunction with inserting the liner 1 provided the seal 2 into an outer pipe 3. By the mentioned diameter decrease of the part of the liner 1 carrying the seal, the outside perimeter of the tube 1 can be kept down in spite of the presence of the seal, which is valu¬ able, since the gap between the liner 1 and exterior pipe 3 is often relatively small.

It can be furthermore suitable to provide the liner 1 with at least one further injection hole 32 situated on the liner such that it is covered by the annularlip 21 of the seal 2, the lip 21 functioning as a non¬ return valve when filler is injected through the hole 42.

^o When a liner 1 provided with a seal 2 is inserted in an outer pipe 3, the seal is thus compressed with the aid of a protective means 50, and the deflection lip 10 is thus forced to assume the insertion position

illustrated in Figure 4. This results in that the liner 1 can be in¬ serted or drawn into the outer pipe 3, e.g. with the aid of a special tool, to a desired final position, the protective means 50 then being removed so that the deflecting lip 10 of the seal 2 can freely expand into engagement against the inner wall 4 of the outer pipe 3, as illus¬ trated in Figure 5. The next step will be to inject a suitable filler 60 into the cavity 14 of the seal 2 via the holes 41 and 19, e.g. with the aid of a remotely operated injection means, so that the cavity is forced to expand suffiently for the outer wall 16 of the seal 2 to be urged against the inner surface 4 of the outer pipe 3, whereby an effective seal between the liner 1 and pipe 3 is achieved. The presence of the cavity 14 in the seal results in that the filler 60 is forced to spread round the entire circumference of the liner 1, which advan¬ tageously contributes to centering the liner 1 relative the outer pipe 3.

As a non-restricting example of a suitable filler, may be mentioned a cement grout of the "type which expands somewhat on curing.

In connection with injecting filler 60 in the cavity 14 via the holes 41 and 19, the annularlip 18 functions on the seal 2 as a non-return valve and prevents the filler from flowing backwards through the holes 19 and 41.

Sometimes tnere is the desire of further locating the liner 1 to the outer pipe 3,and then filler can be further injected via the hole 42, the rearward annular, lip 1 serving as a non-return valve. Trie seal 2 thus prevents the filler leaking out past the free end of tne liner 1, and a corre∑sponding seal 2 in the other end of a group of interconnected linersprevents outwardleakage of the filler in this direction.

It will be understood that the inventive seal 2 can be fitted to other places along the liner than have been shown here, and it can sometimes be advantageous to arrange along an interconnected group of liners one or more seals 2 solely with the object of iπproving guidance of the liner 1 relative the surrounding pipe 3.

It will also be understood that there are large selection possibilities with regard to the type of filler.

The inventive seal can of course be used in connections other than the above-described relining method.

Manufacture of the inventive seal 2 suitably takes place on a cylin- drically shaped tool corresponding to the inner contour of the finished • seal, the number of required layers of so-called vulcanising rubber being applie . to the tool. In such a case it is important that each layer of rubber fits tightly, i.e. it is well stretched, against the previously laid layer, and that in the parts of the seal where integral vulcanisation is not desired between the different layers of rubber an aluminium foil or the like teπperature resistant material is laid so that such vulcanisation is prevented. This applies to the gaps 24- 26 in Figure 3, for example.

By stretching each layer laid on the tool well, there is obtained an ai_r-free seal which, as mentioned above, is extremely essential. Vul¬ canising the different rubber layers together in the parts where this is to take place is subsequently carried out, e.g. in an oven.

It should also be mentioned that a suitable grease, salve or powder can optionally be used instead of foil in the parts of the seal where integ¬ ral vulcanisation is to be inhibited.

The invention is not restricted to what has been shown and described, and amendments and modifications of it are conceivable within the scope ol ^' the following claims.