GB2113608A

GB2113608A - Composite materials and internal lining sheaths for conduits or ducts made of such materials

Info

Publication number: GB2113608A
Application number: GB08301365A
Authority: GB
Inventors: Alain Renaud
Original assignee: Coopetanche SA
Current assignee: Coopetanche SA
Priority date: 1982-01-21
Filing date: 1983-01-19
Publication date: 1983-08-10
Also published as: CH656093A5; IT1160457B; GB8301365D0; GB2113608B; IT8319215A0

Abstract

A flexible integral composite material is formed by at least one assembly comprising on its upper portion a first non-woven fabric (1) and at least one flexible reinforcement (2) under at least a portion of said first non-woven fabric, while a second non-woven fabric (3) may be disposed on the lower portion of said assembly. A flexible, sealing sheet having a substantially smooth external face can be fixedly connected to the lower face of the second non-woven fabric. The invention also concerns lining sheaths made with the above- mentioned material, and the process for internally lining damaged conduits with said sheaths. <IMAGE>

Description

SPECIFICATION Composite material and internal lining sheaths for conduits or ducts made of such materials The present invention concerns flexible integral composite materials which can be used in particular for making internal lining sheaths for conduits or ducts which have suffered damage, for example. The invention also concerns such sheaths and processes for internally lining the conduits or ducts by means of sheaths made from said composite materials.

The materials used hitherto for internal lining sheaths for a damaged conduit for example are not provided with a reinforcing member therein. Thus, for conduits of substantial diameters, the thickness of the sheath becomes considerable in order to provide the necessary resistance to cracking and possible rupture. In addition, such composite materials generally comprise an external layer or the like, which is capable of absorbing an adhesive, with the external face of that layer being applied against the internal face of the conduit until the adhesive hardens, the conduit then being provided with a protective sheath.Now, as the thickness of the sheath necessarily increases in dependence on the section of the conduit to be lined, the thickness of the external absorbing layer also increases and consequently the amount of adhesive to be used in order to ensure that the sheath adheres to the conduit increases not only in dependence on the external surface area of the sheath (and therefore the section of the conduit) but also, and in a disproportionate manner, in dependence on the thickness of the adhesive-absorbing layer of the sheath.

This means that the sheath becomes excessively heavy and the pressures required for applying the sheath against the conduit become increasingly substantial, which makes it very difficult to insert the sheath into the conduit, apply it against the internal face of the conduit and maintain the application pressure until the adhesive hardens. Finally, the cost of the equipment involved and the lining operation becomes excessive.

The materials in accordance with the present invention are comparatively light and easy to handle, while enjoying considerable mechanical strength.

The present invention seeks to remedy the above-indicated disadvantages. In accordance with the present invention, the flexible, integral composite material is characterised in that it is formed by at least one assembly comprising on its upper portion a first non-woven fabric and at least one flexible reinforcement under at least a portion of said first nonwoven fabric, with or without a second nonwoven fabric disposed on the lower portion of said assembly; and with or without a flexible, sealing sheet having a substantially smooth external face fixedly connected to the lower face of said second non-woven fabric.

The above-defined material is also characterised in that said first non-woven fabric may be the same as said second non-woven fabric.

The layers of non-woven fabric are made of natural or synthetic fibres such as fibres of cotton or the like, polyester and the like, glass fibres and the like.

The reinforcement or reinforcements may be or are made of a strong flexible material such as glass fibres or the like.

The reinforcement or reinforcements may be or are made in the form of a woven fabric or a mesh or netting.

The flexible sheet is made of a natural or synthetic material such as rubber or the like, polyvinylchloride, polyethylenebutyl and the like.

In accordance with a first embodiment, said material is characterised in that it is formed by at least one assembly comprising on its upper portion a layer of a non-woven fabric and on its lower portion at least one flexible reinforcement, wherein a plurality of assemblies can be assembled upon each other, and by a layer of non-woven fabric, which is fixedly connected to the last reinforcement; a flexible, sealing sheet having a substantially smooth external face may optionally be fixedly connected to the lower face of the last layer of non-woven fabric.

In accordance with a first embodiment of the internal lining sheath for a conduit, which is damaged for example, the sheath is characterised in that it is made of a material formed by at least one assembly comprising a first layer of a non-woven fabric for example of polyester and at least one flexible reinforcement of a strong material such as glass fibres, and by a lower layer of a non-woven fabric forming the internal face of the sheath, all of which said layers can absorb an adhesive material such as a thermosetting resin.

In accordance with a second embodiment, the sheath for internally lining a conduit which is damaged for example is characterised in that it is made of a material formed by at least one assembly comprising a first layer of a non-woven fabric, for example of polyester, and at least one flexible reinforcement of a strong material such as glass fibres, and by a lower layer of a non-woven fabric and by a flexible, sealing, smooth sheet forming the internal face of the sheath, the layers of nonwoven fabric and the one or more reinforcements being capable of absorbing an adhesive material such as a thermosetting resin.

A A first process for internally lining a conduit or duct is characterised in that a sheath corresponding to the first embodiment referred to above is introduced into the conduit, that the internal face of the conduit and/or the external face of the sheath, which is made of a permeable material, is coated with an adhesive material, that an inflatable mould is introduced into the sheath, said mould being formed by a sheet or membrane of a material which does not adhere to the sheath under the action of the thermosetting resin such as polyethylene or polyvinylchloride, that said mould is inflated while possibly increasing the temperature to apply the sheath firmly against the internal face of the conduit, and that the mould is deflated and withdrawn after the resin has hardened.

That sheath, which corresponds to the first embodiment referred to above, is made from a a sheet of a material which is entirely permeable to the thermosetting resin, so as to assume a tubular shape, the outside diameter of which is slightly less than the inside diameter of the conduit; the ends of the sheet which is coated with the resin are connected by an overlap joint which permits one end to slide relative to the other as long as the resin has not set, so that the section of the sheath can increase under the effect of the pressure applied by the inflated mould until the sheath is perfectly and firmly applied by means of its external face against the internal face of the conduit.

A second process for internally lining a conduit is characterised in that a sheath corresponding to the second embodiment referred to above is introduced into the conduit so that at least one end of the sheath projects substantially beyond the end of the conduit, that the edges of the end of the sheath are brought together until they touch, that said edges are caused to adhere to each other, for example by welding, in order to seal said end of the sheath; that the internal face of the conduit and/or the external face of the sheath is or are coated with an adhesive material such as a thermosetting resin; that the sheath is then applied against the internal face of the conduit by applying a uniform pressure to the internal face of the sheath while possibly increasing the temperature within the sheath until the adhesive hardens, and that said pressure applying the sheath to the conduit is then reduced.

In accordance with a third embodiment of said material, it is characterised in that it comprises a first layer formed by a flexible, sealing sheet having a substantially smooth external face, a second layer formed by fibres forming a felt which is fixed to the internal face of said first layer, a flexible reinforcing member being embedded in said second layer so that, without friction between itself and said layer, it can follow any deformation of said second layer and said first layer which are intimately fixed to each other so as to form said flexible integral composite material.

Said first layer of the material is made for example in the form of a flexible, sealing sheet of a natural or synthetic material such as rubber or the like, polyvinylchloride, polyethylene, butyl and the like.

The second layer may be made of natural or synthetic textile fibres such as fibres of cotton and the like, polyester and the like, and glass fibres, said reinforcement being disposed substantially halfway through the thickness of said second layer. The reinforcement is made of a strong flexible material such as glass fibres and the like. The reinforcement may be made for example in the form of a mesh or netting. The dimensions of the warp of the mesh or netting may be larger than those of the weft.

The invention also concerns a sheath for internally lining a conduit which is damaged for example, characterised in that it is made of a material corresponding to said third embodiment described hereinbefore, wherein the internal face of said material is an integral part of said first layer and is smooth and impervious, the external face of said material is an integral part of said second layer which is provided with a reinforcement, and said second layer is capable of absorbing an adhesive material such as a thermosetting resin. The warps (or the wefts) of said reinforcement which is made in the form of a mesh or netting are disposed in the direction of the longitudinal axis of the sheath while the wefts (or the warps) are disposed perpendicularly to said warps.Or, alternatively, the warps and wefts are disposed diagonally with respct to the longitudinal direction of said sheath.

Finally, the invention concerns a process for internally lining a conduit, characterised in that a sheath is introduced into the conduit and that the internal face of the conduit and/or the second layer which is provided with a reinforcement is or are coated with an adhesive material such as a thermosetting resin; that the sheath is then applied against the internal face of the conduit, applying a pressure to the internal face of the sheath while possibly increasing the temperature within the sheath until the adhesive hardens, and that said pressure applying the sheath against the conduit is then reduced. Such a process may be in accordance with that filed in the form of a patent application in France on 19th April 1980 under the No 80 08679, which was published under the No 2 480 910.

Other advantages and features will be apparent from the following description which is given by way of example and from the drawings referring thereto, in which: Figure 1 shows a view in cross-section on an enlarged scale of a first embodiment of the composite material.

Figure 2 shows a view in cross-section and on an enlarged scale of a second embodiment of the composite material, Figure 3 shows a view cross-section on a small scale of a sheath made with the material shown in Fig. 1, Figure 4 shows a view in cross-section on a small scale illustrating installation of a sheath made with a material as shown in Fig. 2, in a conduit or duct, Figure 5 shows a view in cross-section of an embodiment of the material according to the invention, and Figure 6 is a perspective view on a larger scale of an embodiment of a member for reinforcing the material in accordance with the invention The material 1 0 shown in Fig. 1 comprises at least one assembly comprising a first layer 1 1 of a non-woven fabric, such as natural or artificial felt. Preferably, the layer 1 is made of polyester fibres.The layer 1 is followed by at least one strong flexible reinforcement 2 made for example of glass fibre cloth or a glass fibre mesh or netting. A number of reinforcements 2 may be disposed one upon the other: for example, a reinforcement comprising fabric may be combined with a reinforcement in the form of a mesh or netting, and so on. If the material has only a single assembly 1, 2, a layer 3 of a non-woven fabric is fixedly connected to the lower face of the layer 2 comprising at least one reinforcement. In that case, the thickness el of the layer 1 may be equal to the thickness e3 of the layer 3; however, that is not necessarily the case; the thicknesses e, and e3 may be so selected as to permit the most advantageous configuration of a material 10 for producing a sheath G1 for example.Likewise, the thickness e2 of the layer comprising at least one reinforcement is selected in dependence on the number of reinforcement members used and the flexibility and mechanical strength which is to be imparted to the material 10 which is to be used to make a sheath G1. The material 10 may comprise a plurality of assemblies: layer of non-woven fabric - reinforcement layer.

The example shown in Figure 1 comprises two assemblies: layers 1, 2 and layers 3, 4; however, the last layer 5 is preferably of a non-woven fabric; it is fixedly connected to the lower part of the last layer which comprises at least one reinforcement.

The thicknesses of the layers of non-woven fabric, as indicated at e, e3, e5 and the thickness of the reinforcement-bearing layers, as indicated at e2 and e4, are so selected as to impart the best possible qualities from the point of view of forming a sheath G, for example. Thus it can be assumed in regard to the material 10 shown by way of example in Fig. 1 that e, = e5, e3 > e, and e2 = e4. The method of assembling the layers to each other does not form part of the invention. It can be envisaged however for example that a strong integral material can be produced by projecting or spraying polyester fibres on to the glass fibre cloth. All the layers 1, 2, 3, 4, 5 are permeable to an adhesive such as a thermosetting resin. That procedure thus produces an integral, light, strong and easily handleable materal 10.Those qualities permit the material 10 advantageously to be used for producing sheaths G, for internally lining conduits. A sheet of the material 10 is rolled to form a tubular element, the outside diameter D of which is slightly less than the inside diameter of the conduit. The ends 10, and 102 of the sheet made from the material 10 form an overlapping joint, which makes it easy to determine the most advantageous diameter D for introducing the sheath G, into the conduit (see Fig. 3). Before it is introduced into the conduit, the sheath is coated with the adhesive which penetrates all the layers of the material 10. The ends 10, and 102 of the sheet can then slide relative to each other as long as the adhesive is still liquid.

When the adhesive-coated sheath G, is introduced into the conduit, a bag or the like which is at least of the same length as the sheath is also introduced into the sheath. The bag is made of a sheet of polyethylene, polyvinylchloride or the like. The adhesive cannot therefore cause that sheet of material to adhere to the sheath. The bag is inflated; the temperature is optionally increased. The sheet of polyethylene, polyvinylchloride or the like is then firmly applied against the lower face of the sheath (the layer 3 or the layer 5) and the sheath G, is firmly applied against the internal face of the conduit. The sheet forming the inflatable bag being smooth, the adhesive cannot flow away on the lower face of the sheath (layer 3 or layer 5) and the latter remains smooth and impervious after the adhesive has set and after the bag has been deflated and withdrawn.When the sheath is applied against the conduit under pressure, the diameter D of the sheath G1 increases, without the material 10 being subjected to stresses. That is made possible by the sliding movement of the ends 10, and 102 of the overlap joint relative to each other before the adhesive sets.

After the adhesive has set, the diameter D then substantially corresponding to the inside diameter of the conduit, the material 10 which is impregnated with hard, polymerised resin permits the formation of a light, strong and impervious sheath G,, the internal face of which is smooth.

The material 11 shown in Fig. 2 is similar to that shown in Fig. 1 except that, as the lower layer, it comprises a flexible, impervious sheet 6 which is fixedly connected to the layer 5 of non-woven fabric. The sheet 6 may be of polyethylene, polyvinylchloride, etc, as is already known from the present applicants' patent application No 82 00933 dated 21st January 1982. The material 11 may serve to form sheaths G2 for internally lining ducts or conduits C (see Fig. 4). At least one of the ends of the sheath G2 is extended into the bottom of the manhole P for access to the conduit or duct in the ground S, so as to project beyond the end of the conduit or duct C. The edges of the end of the sheath G2 are then pressed against each other and joined for example by welding. That therefore seals the sheath G, at one of its ends.The layers 1 to 5 of the material 11 forming the sheath G, are impregnated with an adhesive such as a thermosetting resin. The adhesive cannot penetrate into the layer 6 nor pass through the layer 6. When the sheath G2 has thus been prepared and introduced into the duct or conduit C, a fluid which is under pressure and possibly also heated acts directly or indirectly against the internal face of the sheath G2. The sheath is applied firmly at its external face against the internal face of the conduit C until the adhesive sets. The portion of the sheath G2, at which the edges are welded together and which projects beyond the end of the sheath or duct C, is cut in line with the wall 20 of the manhole P, for example. The sheath G2 is in position.

The material M shown in Fig. 5 is of a thickness e and comprses a first layer 100 whcih may comprise a flexible impervious sheet of a natural or synthetic material such as rubber, butyl, polyvinyl chloride, polyethylene, etc. The thickness of the layer 100 is e20.

In the case of a sheath for internally lining a conduit or duct, the sheet 100 forms the internal layer of the composite material; the free bottom face thereof is therefore preferably smooth in order to minimise friction between the fluid flowing in the conduit, and the lining. A second layer 110 which is of a thickness e10 is fixed to the first layer 100.

The second layer 110 is formed by a synthetic or natural felt provided with a flexible reinforcement 120 disposed substantially halfway through the thickness (at e10/2) of the layer 110. The felt is formed by cotton fibres for example or preferably polyester fibres which are for example flocked or applied under pressure in a hot condition (for example by calendering) to the upper face of the sheet or layer 110, the reinforcement 120 being set in position prior to the flocking or hot calendering operation for example. As the manner of producing the material M is not part of the present invention, it is not described herein.

The felt referred to above is intended to absorb and retain an adhesive when the lining sheath is applied under pressure against the internal face of the duct or conduit; it is in accordance with the scope of the present invention for the adhesive to be applied to the layer 1 10, to the internal face of the conduit or duct or to both (layer and conduit). The reinforcement 120 is preferably but not exclu- sively formed by a glass fibre mesh or netting for example. The mesh or netting shown in Fig. 2 has warps 122 and wefts 121 which are disposed perpendicularly relatively to each other. The dimensions of the warps 122 may be greater than those of the wefts 121 for example. In accordance with one embodiment of the sheath, the warps 122 are disposed in the direction of the longitudinal axis of the sheath.However, it is also possible for the reinforcement 120 to be embedded in the layer 110 in such a way that, when the material M is produced, the wefts 121 are disposed in the direction of the longitudinal axis of the sheath formed by said material M.

In accordance with another embodiment, the warps 122 and weft 121 of the reinforcement 1 20 may be disposed diagonally with respect to the longitudinal axis of the sheath.

As already mentioned above, the reinforcement 120 imparts increased strength to the assembly of the material M, the total thickness e of which will vary only within comparatively small proportions in dependence on the increase in diameter (or in section) of the conduit or duct which is to be provided with an internal lining sheath formed from said material M. Also, the amount of adhesive will increase only be a comparatively small amount, since the thickness e,0 of the layer 110 will increase only slightly. The total weight of the lining sheath comprising the adhesive still remains comparatively low; consequently, the pressure required for applying the sheath against the internal face of the conduit or duct increases only slightly in dependence on the diameters (or the section) of the conduit or duct.A saving in energy is therefore attained, reative to the known lining processes; the consumption of adhesive is lower than in the known processes; and the amount of material M is less than that required in the processes performed hitherto.

Also, the equipment required for generating the pressure for applying the sheath against the conduit and for applying the adhesive may be lighter than that used on existing sites.

There is therefore a saving of energy and in the amount of materials, and a reduction in the cost of the process.

Many improvements and modifications may be made without thereby departing from the scope of the invention. For example, the reinforcement may be of a different configuration from that of a mesh or netting, the thickness of the absorbing layer may be very small and the flexible impervious sheet may be in the form of a-thin membrane. It is also within the scope of the invention to use the material according to the invention for making sheaths which are of square, octagonal, oval, etc sections, to be applied against conduits or ducts or the same sections.

Claims

1. A flexible integral composite material formed by at least one assembly comprising on its upper portion a first non-woven fabric and at least one flexible reinforcement under at least a portion of said first non-woven fabric, with or without a second non-woven fabric disposed on th lower portion of said assembly; and with or without a flexible impervious sheet having a substantally smooth external face fixedly connected to the lower face of said second non-woven fabric.

2. A material according to claim 1, in which said first non-woven fabric is the same as said second non-woven fabric.

3. A material according to claim 1 or claim 2, in which the layers of non-woven fabric are made of natural or synthetic fibres such as fibres of cotton and the like, polyester and the like, glass fibres and the like.

4. A material according to claim 1, claim 2 or claim 3, in which the reinforcement or reinforcements is or are made of a strong flexible mterial such as glass fibres or the like.

5. A material according to claim 4, in which the reinforcement or reinforcements is or are made in the form of a woven fabric or a mesh or netting.

6. A material according to any one of the preceding claims, in which said flexible sheet is made of a natural or synthetic material such as rubber and the like, polyvinylchloride, polyethylene, butyl and the like.

7. A flexible integral composite material according to one of claims 1 to 6 characterised in that it is formed by at least one assembly comprising on its upper portion a layer of a non-woven fabric and on its lower portion at least one flexible reinforcement, wherein a plurality of assemblies can be assembled to each other, and by a layer of a non-woven fabric, which is fixedly connected to the last reinforcement; wherein a flexible impervious sheet having a substantially smooth external face may optionally be fixedly connected to the lower face of the last layer of non-woven fabric.

8. A sheath (G,) for internally lining a conduit or duct which is damaged for example, characterised in that it is made of a material (10) formed by at least one assembly comprising a first layer (1, 3) of a non-woven fabric, for example polyester, and at least one flexible reinforcement (2, 4) of a strong material such as glass fibres, and by a lower layer (3, 5) of a non-woven fabric forming the internal face of the sheath, all said layers being capable of absorbing an adhesive material such as a thermosetting resin.

9. A sheath (G2) for internally lining a conduit or duct which is damaged for example, characterised in that it is made of a material formed by at least one assembly comprising a first layer (1, 3) of a non-woven fabric, for example polyester, and at least one flexible reinforcement (2, 4) of a strong material such as glass fibres, and by a lower layer (3, 5) of a non-woven fabric and by a flexible, impervious and smooth sheet (6) forming the internal face of the sheath, the layers of non-woven fabric and the reinforcement or reinforcements being capable of absorbing an adhesive material such as a thermosetting resin.

10. A process for internally lining a conduit or duct characterised in that a sheath (G1) as set forth in claim 8 is introduced into the conduit or duct, that the internal face of the conduit or duct and/or the external face of the sheath, which is made of a permeable material, is coated with an adhesive material, that an inflatable mould is introduced into the sheath, said mould being formed by a sheet or membrane of a material which does not adhere to the sheath under the effect of the thermosetting resin, such as polyethylene or polyvinylchloride, that said mould is inflated, while possibly increasing the temperature, to apply the sheath firmly against the internal face of the conduit or duct (C), and tht the mould is deflated and withdrawn after hardening of the resin.

11. A process according to claim 10 characterised in that the sheath (G,) is made from a sheet of a material that is entirely permeable to the thermosetting resin so as to be capable of assuming a tubular shape, the outside diameter (D) of which is slightly less than the inside diameter of the conduit or duct; the ends of the resin-coated sheet are connected by an overlapping joint which permits one end to slide relative to the other as long as the resin is still not hard, so that the section of the sheath may increase under the effect of the pressure applied by the inflated mould until the sheath is firmly and perfectly applied by means of its external face against the internal face of the conduit or duct.

1 2. A process for internally lining a conduit or duct characterised in that a sheath (G2) as set forth in claim 9 is introduced into the conduit in such a way that at least one end of the sheath (G2) projects substantially beyond the end of the conduit or duct, that the edges of the end of the sheath are brought together until they touch, that said edges are caused to adhere to each other for example by welding in order to seal off said end of the sheath; that the internal face of the conduit or duct and/or the external face of the sheath is coated with an adhesive material such as a thermosetting resin; that the sheath is then applied against the internal face of the conduit or duct by applying a uniform pressure over the internal face of the sheath while optionally increasing the temperature within the sheath until the adhesive hardens, and that said pressure applying the sheath against the conduit or duct is then reduced.

13. A flexible integral composite material according to one of claims 1 to 6 characterised in that it comprises a first layer formed by a flexible impervious sheet and having a substantailly smooth external face, a second layer formed by fibres forming a sheet which is fixed to the internal face of said first layer, a flexible reinforcement member being embedded in said second layer in such a way that, without friction between itself and said layer, it can follow any deformation of said second layer and said first layer which are intimately fixed together so as to form said flexible integral composite material.

14. A material according to claim 13 characterised in that said first layer is made in the form of a flexible impervious sheet of a natural or synthetic material such as rubber and the like, polyvinylchloride, polyethylene, butyl and the like.

15. A material according to claim 13 or claim 14 characterised in that the second layer is made of natural or synthetic fibres such as fibres of cotton and the like, polyester and the like, said reinforcement being disposed substantially halfway through the thickness (e1/2) of said second layer.

16. A material according to one of claims 13 to 15 characterised in that the reinforcement is made of a strong flexible material such as glass fibres and the like.

17. A material according to claim 16 characterised in that the reinforcement is made in the form of a mesh or netting.

1 8. A material according to claim 17 characterised in that the dimensions of the warp of said mesh or netting are larger than those of the weft.

19. A sheath for internally lining a conduit or duct which is damaged for example characterised in that it is made of a material according to one of claims 13 to 18, the internal face of said material forming an integral part of said first layer and being smooth and impervious, the external face of said material forming an integral part of said second layer which is provided with a reinforcement, which second layer is capable of absorbing an adhesive material such as a thermosetting resin.

20. A sheath according to claim 19 characterised in that the warps (or wefts) of said reinforcement which is made in the form of a mesh or netting are disposed in the direction of the longitudinal axis of the sheath while the wefts (or the warps) are disposed perpendicularly to the warps.

21. A sheath according to claim 19 characterised in that the warps and wefts are disposed diagonally with respect to the longitudinal direction of said sheath.

22. A process for internally lining a conduit or duct characterised in that a sheath as set forth in one of claims 19 to 21 is introduced into the conduit or duct, that the internal face of the conduit or duct and/or the second layer which is provided with a reinforcement is coated with an adhesive material such as a thermosetting resin; that the sheath is then applied against the internal face of the conduit or duct by applying a pressure to the internal face of the sheath while optionally increasing the temperature within the sheath until the adhesive hardens, and that said pressure applying the sheath to the conduit or duct is then reduced.

23. A flexible integral composite material substantially as hereinbefore described with reference to Fig. 1, 2 or 6 of the accompanying drawings.

24. A sheath for internally lining a conduit or duct, substantially as hereinbefore described with reference to Fig. 3 or Fig. 4 of the accompanying drawings.