This invention relates to lining materials for the lining of pipelines and passageways, and such materials are constructed in accordance with the invention in a fashion which enables the lining materials in fact to be used to produce pipes which can be employed in general utilisation, as opposed as being used for the lining of pipelines and passageways.

The lining processes which are known for the lining of pipelines and passageways comprise the utilisation of a flexible lining tube which includes at least one resin absorbent layer. That resin absorbent layer is impregnated with a curable synthetic resin, and the tube whilst impregnated but whilst still flexible is then shaped to the pipeline or passageway surface using fluid pressure. Whilst the pressure is still applied, the resin is caused or allowed to cure forming a hard and rigid lining pipe on the pipeline or passageway surface. These lining processes are known as soft-lining processes.

The lining tube may simply be pulled into the pipeline or passageway and then inflated using fluid pressure, or alternatively the lining may be everted into and along the pipeline or passageway again using fluid pressure. The present invention applies to either method, but has best utility in the case where the lining tube is simply pulled into the pipeline or passageway. Also, the present invention applies where the lining tube is simply inflated in free space so as it takes up the form of a circular sectioned tube, and when the resin cures a f ee-standing and usable pipe is produced.

The known lining tubes comprise essentially one or more

layers of a fibrous felt to absorb the resin, and to the outside of the lining tube there may be an impermeable film to retain the resin inside the tube. The impermeable layer may be a coating bonded to the outermost layer of felt.

There is a demand for providing these lining tubes with reinforcement in order to provide greater hoop strength in the finished rigid lining or pipe, and the present invention is concerned with the provision of such reinforcement which is in accordance with the invention in the form of one or more layers of woven fibrous material wrapped around the inner layer or inner layers of resin absorbent material, said reinforcement layer(s) being simply wrapped and overlapped around the inner absorbent layer or layers, so that as the lining tube is inflated to size, the overlapped edges of the reinforcing layer or layers will slip relative to each other to enable said reinforcing layer(s) to expand.

Preferably the overlapped edges of the layer or layers of woven fibrous material are adhered by means of an adhesive substance such as a hot melt adhesive which loses its adhesion when the lining tube is impregnated with the resin or when the tube is heated.

It will be seen therefore that in the preferred case the reinforcing tubular layers are temporarily held in tubular form by the adhesive but can expand due to loss of adhesion during the inflation process.

Preferably, there will be two or three of said reinforcing layers which may be of synthetic fibres or glass fibres or the like, and the overlap positions of the respective layers will be angularly offset, for example by 90 degrees relative to each other in order to ensure that the overlap portions do not create an

excessively thick region in the lining tube.

In one embodiment of the invention, the tube comprises an inner layer of fibrous felt which is a web formed into tubular form with the free edges in butting contact, said edges being connected to each other by sewing extending across the butted edges. Around the absorbent layer are then placed the reinforcement layers and in the preferred case the adhesive or other temporary connection means applied to hold the fibrous layer in position. Second and third layers of reinforcement may be applied. Finally, to the outside of the reinforcement layer or layers may be applied a film of impermeable material or another felt layer with an outer impermeable coating.

When the interior of such a lining tube is impregnated with synthetic resin, the adhesive or other bond when provided between the overlapped edges of the reinforcement layers is lost, and when the lining is expanded to circular form, for example by everting a film tube into the centre of the lining tube, the reinforcement layers slip to the degree as necessary, but become embedded in the synthetic resin and the resulting inflated tube throughout its thickness becomes a homogeneous mass of resin with the reinforcement layers embedded therein and when the resin cures, a reinforced tubular structure results.

Typically the lining tube may be inflated after it has been impregnated and then placed inside the pipeline or passageway to be lined.

In one embodiment, the pipeline or passageway is slightly shorter than the length of the tube, so that the tube ends protrude from the pipeline or passageway and around such ends are placed formers in order to taper the ends

of the rigid lining when the resin has cured thereby enabling the placement on said ends of flange couplings which may be moulded components moulded from a similar synthetic resin so that the flange couplings can be adhered to the ends of the rigid lining tube to provide a means for connecting the rigid lining tube to for example another coupling or a similar tube.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings wherein,•-

Figs. 1, 2, 3 illustrate diagramatically a process for the lining of an underground sewer;

Fig. 4 is a cutaway perspective view of the lining tube which is used in the process of Fig. 1, and which is constructed according to an embodiment of the invention;-

Fig. 5 is a diagrammatic elevation of the end of the lining tube and a flange for fitting thereto; and

Fig. 6 is a sectional elevation of the flange and lining tube end when fitted together in conjunction with a steel flange.

Referring to the drawings in Figs. 1 to 3, an underground sewer pipe (10) is to be lined between a pair of manholes (12) and (14). The sewer (10) is lined using a lining tube (16) which is pulled into the pipe (10) as shown diagrammatically in Fig. 1 using a pre-lining flexible plastic tube (18) which is anchored at position (20) at the right hand end of the sewer and then is everted using fluid pressure, e.g. air or water, into the sewer (10) so as to pull the lining tube (16) into the position shown in Fig. 2. When the tube (16) is in

position as shown in Fig. 2 a second flexible plastic tube (19) connected to the trailing end of the tube (16) is everted into the tube (16) as shown in Fig. 3 to inflate the tube (16) against the surface of the sewer (10). The tube (16) is of a material which absorbs a curable synthetic resin, and such material is in fact impregnated with the synthetic resin. The synthetic resin is caused or allowed to cure when the tube is in the position shown in Fig. 3 so that when the resin cures, the resulting liner (16) becomes a hard lining pipe which is free-standing and lines the sewer surface.

The eversion of the second tube (19) into the tube (16) is also by means of fluid pressure such as air or water pressure.

As the lining (16) cures, the ends which project into the manholes (12) and (14) are formed so as to be tapered on the outside as shown by means of formers (22) and (24) which may be metal rings.

A formed rigid end of the tube (16) is shown in Fig. 5 and shown in conjunction therewith is a flange (26) which is adapted to be fitted to the tapered end (28) of the rigid tube (16). The inner surface (30) of the flange ring (26) may also be tapered as shown in Fig. 6 so that the flange can be securely fixed to the tapered end (28). The fixing may be by means of adhesive or simply by the bonding of the tube (16) to the flange (26) in that the flange (26) preferably is formed of the same synthetic resinous material. As shown in Fig. 6, the flange (30) is bonded to the rigid tube (16) and a coupling ring or plate (32) preferably of steel is mounted around the flange so as to serve as a means of coupling the pipe end to for example another pipe end or an appropriate coupling.

The construction of the lining tube (16) is shown in Fig.

4 and it will be seen to comprise an inner tube (34) which is a web formed into tubular form so that the butting edges (36) and (38) come together and they are connected by means of sewing stitches (40).

Around the tube (34) is a reinforcement tube (42) which is formed by wrapping a web of woven reinforcing material around the inner tube (34) until the edges (44) and (46) overlap. The tube (42) is preferably of a fibrous material, the fibres being synthetic fibres and/or glass fibres to give hoop strength to the resulting rigid pipe (16). Where the edges (44) and (46) overlap they may be temporarily connected as indicated by reference (48) by for example hot melt adhesive or other means which will be released when the tube is impregnated with the synthetic resin.

A further reinforcing tube (50) which is identical to tube (42) is applied around tube (42) except that the overlap (51) is angularly displaced relative to the overlap (44) , (46) .

Finally, around the tube (50) is applied an outer felt tube (52) which is similar to tube (34) except that it is provided with an outer impermeable coating (54). Where the butting edges are connected by sewing (56) there is applied a tape (58) to seal the stitches to prevent escape of the resin.

The tube (16) is impregnated with resin by pumping same into the interior of the tube as indicated by arrow (60), and by pressing the tube by means of nip rollers in order to ensure even distribution of the resin throughout the layers (34), (42), (50) and (52). As the resin impregnates these layers, so the adhesions spots, when provided (48) are released and the tubes (42) and (50)

are in fact free to expand under the inflation pressure when the tube (16) is inflated to the condition shown in Fig. 3.

Although the reinforcing tubes (42) and (50) are described as being of woven construction for strength, they could be of another textile material configuration.

It will be appreciated that the overlapped layers are dimensioned preferably so that the overlap is not completely lost as the tube expands. The fact that there is no positive connection between the overlapped layers does not affect the linings final strength as the reinforcement layers become embedded in the hard, cured resin.