CA2230806A1

CA2230806A1 - Method and apparatus for the manufacture of a tube for lining pipelines and sewer systems

Info

Publication number: CA2230806A1
Application number: CA002230806A
Authority: CA
Inventors: Michael Henze
Original assignee: Rothenberger Rohrsanierung Gmbh; Michael Henze
Current assignee: Rothenberger Rohrsanierung GmbH
Priority date: 1997-03-07
Filing date: 1998-02-27
Publication date: 1998-09-07
Also published as: EP0863359A1; PL325190A1; JPH10272696A

Abstract

In the manufacture of a tube for lining pipelines and sewer systems from fiber materials which can be impregnated with a curable resin, the margins (6a, 6b) of fiber strips (6, 19) on the circumference of the tube are provided with at least one tightly bonded overlap area (7a, 7b) running lengthwise. To achieve a stable and elastic foreproduct for impregnation with resin, a) elastically expandable fiber materials are used for the fiber strips (6, 19),b) the margins (6a, 6b) of the fiber strips (6, 19) are bonded irreversibly to one another by a thermal process, by either b1) placing a curable resin between the margins (6a, 6b) and curing it by actinic radiation, or b2) the fiber materials are bonded to one another in the overlap area (7a, 7b) by superficial fusion and pressure. In this case the fiber materials have differentmelting temperatures on opposite faces and are heated at their surfaces in contact to a temperature that is between the melting temperatures of the two fiber materials.

Description

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METHOD AND APPARAl'US FOR THE MANUFACTURE OF A
TUBE FOR LINING PrPELINES AND SEWER SYSTEMS

The invention n lates to a method for manufacturing a tube for lining pipelines and sewer 5 systems with at least one inner layer concistin~ of a fiber material and impregnated with a curable resin, the ,-,ar~ s of which are provided with at least one overlap area running -lengthwise and 'bonded on the circumference of the tube by ~upe- i...position on an equal or another fiber strip, and which are then surrounded with an external film that is impermeable to the resin.
1() Such tubes are c:alled "liners." Both their manufacture and their installation in the repair of pipelines and sewer systems are complicated and time-concuming, especially when it is a question of the manufacture and processing of tubes of great length. After the layer of the impregn~ted fiber material formed into a tube has cured it is then the supporting element. To 15 achieve great strength the resin and fiber material must be free insofar as possible of voids which may form due to air inclusion but also due to insufficient impregnation of the fiber material. The curing of the resin can be performed either by heat or by visible light or ultraviolet light. A whole series of resin rnaterials are marketed for this purpose, and activators and accelerators can be added to them to accelerate curing. Also known are cold-setting resins 20 in which the curing is retarded, but in which a temperature rise occurs during the curing process.

Such tubes or liners can, for example, be drawn in the flat state into the repair area, and after the at~c~ment of so-called "end closers" they can be inflated by a medium under pressu.e and 25 urged against the walls to be repaired. Another method of installing the tube or liner consists in what is known as eversion, turning it inside out. In both cases, to facilitate handling the tube, the impre~n~ted fiber material is enveloped by a gas-impermeable outer layer of tubular film, which of course is also impermeable to resin. When such a tube is inflated, this external film comes in contact with the wall surface, and the impregnated fiber material is on the inside.
30 In order then the be able to transport radiation sources through such an inflated tube to cure it, a tubular interna~l film is pulled into this tube at the worksite. In the case of eversion this is unnecess~ry, sin,ce eversion brings the originally internal impregnated material to the outside, but the process of eversion and the subsequent transport of the radiation sources through the inside-out tube iis not easy to accomplish.

It is especially difficult in this case to pe,l'or", a uniform i",p,t;gnation, especially when at least one of the surfaces of the fiber material is provided with a film. As a rule, therefore, the procedure has b~een first to finish the tube or liner by performing the imbibing or i",preg,nalion at the worksite. In the eversion operation methods have even been used in which the fiber 10 material is impregnated with the resin first at the location of the eversion. This calls for the plepa,~ion of approp-,ate apparatus and their operation at the worksite, so that a permanent set-up of the app&,~ s is required.

In the manufacture of a repair liner for pipelines and sewer systems, German Patent 22 40 153 C2 and U.S. Pat,ent 4,009,063 have disclosed folding an impregnatable fiber strip, prior to hl,prey~llation with a curable resin, around an inner tube of film and binding the overlapping area thus formecl by stitching, cementing or welding. In the case of stitching or welding, however, sunken points develop which look like a quilting seam in cotton batting and detract from the strengt~h of the cured tube. This is especially the case when only a single fiber strip is 20 used, because then there is no random distribution of weak points. Nothing is said about the nature of the cernent or of the cementing process. Broad area cementing, however, interferes with the impregnation and the evacuation required before the impregnation; moreover, most cements do not penetrate deeply enough into the fiber strips, so that the danger exists that portions of the surface of the fiber strip wiill be torn out with the cement if tensile stresses 25 occur. Most glues contain solvents and/or plasticizers which produce voids in the finally applied impre n~tin~ resin by forming bubbles and thus create weak points. Lastly, many cements are softened by the impregn~ting resins later applied, and also they do not bond with the i",plegn~l;ng resins.

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European Patenlt 0 275 060 Al discloses i'or the same purpose wrapping a fiber strip, with an external film already applied, around an internal tube while abutting the edges of the fiber strip against one ano1:her and stitching them together. In order to seal and strengthen the seam which also pass~ s through the extemal fillm, a seam strip is then cemented on. In this case, 5 however, it is not possible to apply additional fiber strips because the external film would i"lel~re with the simultaneous evacuation and implegnalion of all fiber strips. The known tube is installed in the pipeline by a so-called "eversion process," such that the fiber strip will be on the outside and the external film on the inside. The purpose is to bond the i"~pr~s"ated fiber strip to the pipeline.
1() WO 91/18234 discloses a similar process wherein the non-overlapped seam is made by butt-welding the fiber strip already provided vvith an internal film. Then the sandwich of internal film and fiber strip is passed through two resin baths and impregnaled therein, and aftervvard provided vvith an external film, which is welded. Such a butt-welded seam, however, forms a lS decidedly weak point, so that a seam strengthening strip must be flame-applied to the seam.
This procedure calls for a very complicated impregnation appa,~ s.

In the cases lefer,ed to above, the ability of the tube to stretch radially is very limited, especially because the seam reinforcing sl:rip does not participate in the stretching and tends to 20 come off. Therefore such seam reinforcing strips have additionally been stitched onto the already impregn~ted tube, thereby causing perforations and leakage in the layered tube.

Through European Patent 0 510 306 A1, ]DE 41 30 459 A1, German Patent 44 27 633 C2 and DE 44 45 166 A2 it is knovvn to refrain from bonding overlapping areas of one or more fiber 25 strips together, s,o that repair tubes with especially good stretchability will be obtained. This has the disadvantage, however, that the overlaps must be made relatively broad so as not to lose the overlap when the tube is stretched. Since the stretching is performed by co",pressed air during installation, the adjacent strips iinle,rele with movement in the broad overlapping areas. Otherwise the margins of the fiber strips can shift, turn over or wrinkle during further Z~PER454-~L/ALT
processing and/or transportation.

In all the aforem~entioned cases there is a description of the manufacture of repair tubes which are already h~pregnated and necessitate very special impregnation methods and either call for S complicated adclitional treatment or they cause the described problems during further procçssing and during transportation due to their unstable structure.

The invention is addressed to the problem of devising a method of the kind described above which will lead to a stable and stretchable foreproduct for a final impregnation, and which will 10 be easy to practice.

The stated problem is solved according tc, the invention, in the process described above, in that:

15 a) a fiber mal;erial which is elastically stretchable in at least the circumferential direction of the tube is used for the at least one internal layer, and that b) before further procçssing the margi:ns of the inner layer are bonded irreversibly together continuously or section by section at junctions by a thermal process, and it is then wrapped in an external film impermeable to the resin, either by bl) placing a curable resin in the alea of overlap between the margins, and after its at least partial penetration into both margins it is cured by actinic radiation through the fiber material, or b2) the ~iber material of at least one of the margins is superficially melted in the overlap area, and the margins are then fused together by the application of pressure.
The invention thus contains - for the solution of the same problem - two alternative ideas for the purpose, wh;ich are based on the same mechanical principle, and both can be performed by a continuous process or also in a cinematic reversal of motion, and they result in sufficient shear strength oi-'the bond.

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In the method using feature bl), a continuous, uninterrupted, varying or meandering, preferably narrow, trail of resin is placed between the contact surfaces parallel to the surfaces ofthe fiber strips, which penetrates sufftciently deeply into the fiber strip, without destroying its fiber structure in the immediate surroundings of the resin trail or producing depressed 5 points, and which is acceptable or compal:ible in the final impregnation with the impregn~ting resin and does not interfere with the micro flows during the impregnation.

In the method using feature b2) at least one of the contact surfaces of the fiber strips is superficially softened with heat, to a suffil~ient depth, and is fused to the other surface by the 1() application of pressure, without completely destroying the fiber structure in the immediate surroundings of the fused area. The addition of foreign substances can be entirely dispensed with, so that the issue of compatibilitv does not arise at all.

Feature b2) is based on the consideration that the higher-melting fibers retain their structure 15 and interstices. In other words the fiber rmaterial does not "collapse" or "fall in." On the other hand, the low-melting fibers become soft or sticky and bond with the higher-melting fibers. It has surprisingly been found that the bond can be separated by great physical force perpendicular to the surfaces in contact, ~A/ith the tearing out of some fibers, but that the bond is quite resistant enough to tangential forc:es to survive the further processing Due to the fact 20 that the warming takes place beginning at the contact surface, i.e., from the inside out, a descending temperature gradient toward both sides takes place, so that by far the greatest part of the fiber struc:ture, even the low-melting fibers, remains intact.

Thus the ability both to sustain a vacuum and to be i,J,plegnated, as well as l,~nsparency to the 25 actinic radiation, even in the seam area, is maintained. The invention is based upon the common consideration of the fusion behavior of the low-melting fibers and their adhesion to the higher-melting fibers without substanfial loss of porosity, so that therefore no undesirable "collapsing" of the fiber strips at takes place at the junction areas. It can be assumed that the higher-melting fibers in this case perform a supporting role for the low-melting fibers.

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By means of the invention, foreproducts for final impregnation can be produced which are stretchable radia~lly, prevent undesirable shifting, tuming over of ~ ins and/or wrinkling of the fiber strip in transport and during furtl1er processing, and do not lead to porosity, capillaries (passage of vapors) and cross-sectional weakening by seams or welds (so-called quilting or 5 cotton-batting e:~ect). Consequently, the number of fiber strips, circul"ferenlially and in thickness, is unlimited. It is emph~ci7ed, however, that the invention also consists in the fact, and proves advantageous, when only one overlap is provided on a tube circumference of 360 degrees, and even if only one intemal layer is present.

10 Also, the resin of the cured resin strips does not soften or become sticky like, for example, an adhesive, which is a foreign substance, but enters into an inseparable bond with the resin of the final impregnation. Lastly, the resin strips do not interfere with the resin flow or the evacuation in the final impregnation. An irreversible process is involved, which cannot be undone.
Due to the elasticity of the intemal layer before the final impregnation is cured, not only is it made possible for the tube to adapt or confomm to irregularities in the pipeline by the action of a pressure medium, but also a bias develo~ps, which is "frozen" into the resin, and like pre~l,essed conc,rete results in an increase of strength and impemmeability, as well as in a static 20 predictability of the cured tube. Hot gases and steam as well as appropliately heated water can be used as press-ure media.

No separation ol'the overlap area~s develops due to unintentional transverse shifting ofthe fiber strips toward one another and/or stretchin~ and hence no weak spots occur, and instead 25 somewhat "seamless" inner layers 12 are formed, even if the overlaps are kept small, which promotes radial stretchability, since shifting of a plurality of inner layers against one another upon stretching is not necçc~ry. This crc,ss shi~ing of course, occurs in the state of the art because the unbonded film strips are not very stretchable themselves, and the overlaps must be staggered on the circumference to avoid bulges.

It is especially advantageous if the same n~sin is used as the curable resin for bonding the margins of the ilmer layer as is used for impregn~ting the rP.m?ining cross section of the inner layer.

5 An additional aclvantage results when the junction or junctions around the circumference of the tube are narrow in proportion to the width of the overlap.

In the case of relatively broad overlaps it is also possible and advantageous to produce at least one, or in the case of the widest overlap, rnore than one junction.
1~
Such a tube can be provided from the outset, in an especially advantageous manner, with an internal tube. This is accomplished by wrapping the at least one internal layer consisting of fiber material around an inner tube that is impermeable to the resin, and by curing the resin of the at least one overlap by actinic radiation after it has been applied.
lS
In this case the inner tube is helpful in prepa~ hlg the inner layer from the fiber material or fiber strips, and it is no longer necessary to pul:l still another inner tube in af'terward.

Manufacture can be performed with any desired number of overlapping zones on the20 circumference of the inner layer, namely by guiding the inner layer, with wall portions ~upelhllposed on at least one overlap, through a g~l1gin~ body, and after the curable resin has been placed in each of the overlaps it is cured.

If it is desired to perform the process on the horizontal it is especially expedient to proceed 25 such that the at least one inner layer consisting of fiber material is formed of two fiber strips of which one is wider than half of the circunrlference of the inner tube and the other has no more than the same width as half of the circumf'erence of the inner tube, that first the wider fiber strip is fed to a receiver and folded in at both its margins, and that the narrower fiber strip is deposited on the same receiver either before or after the wider fiber strip has been folded, ZAP~ R 454 - )EL/ALT
forming two overlap areas of the two margins, the curable resin being placed into both of the overlap areas, while either bl) in both overlap areas a curable resin is put between the margins and after at least partial penetration into the superimposed margins is hardened by ra~i~ting energy through the fiber material, or b2) the fiber material is heat-softened swperficially in each overlap area, whereupon the margins become fused together with the application of pressure.

The receiver can consist of a simple work table, or advantageously of a conveyor belt. The 1() depositing can a.lso be made indirectly - f'or example when an inner tube is lying on the recelver.

This method of production has the great advantage that the folding is performed only on the top of the receiver. Thus it is not necessary - as it is in the state of the art - to fold alternately 1 S from the bottom up and then from the top down around the previously formed tube sandwich.
This is because special problems are involved in folding on the bottom. The state of the art concerns itself also only with folding over without any bonding of the individual fiber strips.

An additional embodiment of the invention also permits the build-up of the inner layer from more than one ilmer layer of fiber material, namely by producing successively on the receiver at least two inner layers consisting of fiber material, and by turning the first inner layer 1~0 degrees before the application of the second and any additional inner layers.

To avoid thickness accumulations due to the multiple overlapping, it is especially advantageous if in the build-up of a tube of more than two inner layers of fiber material the layers of the overlap areas are distributed by the relative transverse shifting of fiber strips on the circumference of the tube.

In the application of the outer film, which must be resistant to the impregnating resin to be ZAPER454-~L/ALT
applied at the end and must be impermeable to it, it is especially advantageous to proceed by using an outer film with a width greater than the circumference of the last inner layer comi~ting of fiber material, and that the outer film, coming from underneath, is folded around the at least one inner layer with the formation of an overlap, and is welded in the overlap area.
';
In a process in which the fiber material on at least one of the margins is softened superficially with heat and then the margins are bonded together by the application of pressure it is advantageous to proceed such that a) the at least one fiber strip on conLo~ ing surfaces is chosen to at least 50% from di~relent 1() fiber materials with different melting te~,l,pe,~ res, b) in every overlapping area the margins of a fiber material with a lower te",pe,~ re and those of a fiber material with a higher melting temperature are placed one on the other, and that c) in every overlapping area at least one of the directly adjacent surfaces is heated beginning 1 S at their swfaces in contact to a temperature that is between the melting temperatures of the two fiber materials.

This is performed in an especially advantageous manner by blowing between the margins of the fiber strip a hot gas with a temperature~ that is between the melting temperatures of the two 20 fiber strips, espe cially by selecting the temperature of the hot gas such that the fiber material with the lower melting temperature fuses within a limited area and bonds with the nonmelting fiber material of the higher melting te",pe,~tllre.

The invention a]lso relates to a tube manui'actured by the method described above and variants 2~ thereof, the important features of this tube being described in claims 20 to 26.

The invention a];so relates to an appa,~ s for the production of a tube with at least one inner layer consisting of at least one impregnatable fiber strip for the lining of pipelines and sewer systems, with an at least substantially horizontal receiver and a conveyor system for carrying _g_ ZAPFR454-~L~ALT
the tube, with at least one supply roll, eac:h roll having an impregnatable fiber strip which can be delivered to the receiver, and with systems for folding the edges of the strips.

For the solution of the same problem such an appal~lus is characterized by:
~;
a) a guiding system for the forrnation c~f at least one overlap area ahead of the receiver by folding the Ill&lt ins of the at least one fiber strip, and by either bl ) at least one nozzle for the appl ication of at least one trail of a resin curable by actinic radiation exclusively in the at least one overlap area between the overlapping margins, as well as at least one curing lamp disposed opposite the resin trails for the formation of an irmer layer closed on its circumference, or by b2) at least one heating body which can be introduced into the at least one ovellapping area and by which the fiber material of at least one of the margins can be 1 c; superficially heat softened to produce a fusion bond, as well as by at least one pressing system for compressing the fusion bond, as well as Iby c) an enveloping system for enveloping the at least one inner layer in an external film.

2~ With such an apparatus, in the minimum case, each inner layer can be made from a single fiber strip. To produce each inner layer from two fiber strips, however, an apparatus is particularly well suited which has the following features:
a) two supply rolls with fiber strips of different width, the broader one of which can be fed from below, and 25 b) a guidance system for forming two overlap areas ahead of the receiver by folding the Illa.~,ins of'the broader fiber strip over the margins of the narrower fiber strip.

Pul ~uanl to still another embodiment of the invention, a design specification is applied to special advantage, in which the transport means consists of a conveyor belt, and in which the -IC~

Z~P~: R 454 - JEL~ALT
guidance systeml for folding the margins of the fiber strip consists of first rails disposed in mirror-image rel.ationship ahead of the conveyor belt, which are adjustable independently of one another transversely of the direction in which the conveyor belt is running.
Thus the transport means can be adapted not only to the manufacture of tubes of di~erent width ("width" r efers to the tube Iying flalt) but the possibilities of adjustment also lead to the fact that the ove:rlap areas can be offset from one another on the circumference. The individual possibilities wil:l be further explained in the detailed description.

Additional advantageous embodiments of the invention will be found in the appa-~lus claims, and their special advantages are also expLIined in the detailed description.

Embodiments o1fthe invention, the proces;s steps and different end products will be described below in conjunction with Figures 1 to 22, and at least the single process steps can be performed continuously.

~Figure 1 shows a first embodiment of a first variant of a first process step for an intermediate product with a resin coating according to Figure 5, showing an apparatus for same in a side view.
2~
Figure 2 is a top plan view of the subject of Figure 1.

Figure 3 is a perspective representation on an enlarged scale of the es.cçnti~l elements of Figures 1 and 2 with the feeding of resin onto the already folded margins of thewider fiber strip prior to the application of the narrower fiber strip.

:Figure 4 is a perspective representation of the essenti~l elements of Figures 1 and 2 with resin being fed onto the margins of the flat-lying narrower fiber strip, before the ,-,a,~,ins of the wider fiber strip are folded over.
-II-ZAPFR454-~L/ALT
~Figure 5 is a c,ross section through a first intermediate product of the process according to Figures 1, 2 and 3.

Figure 6 shows a cross section through a first intemmediate product of the process according 'i to Figures 1, 2 and 4.

Figure 7 sho~AJs a final process step before the impregnation, for wrapping intemmediate products from the processes according to Figures 1 to 4 in an extemal film according to Figures 9 or 10.
1() Figure 8 is a plan view of the subject oi'Figure 7.

Figure 9 is a cross section taken throug~h a first preliminary end product of the process according to Figures 1 to 3 after tuming 180 degrees and after wrapping in a second inner layer of a fiber material, and also after wrapping in an extemal film according to Figures 7 and 8.

Figure 10 is a cross section through a second preliminary end product ofthe process according to Figures 1, 2 and 4 after tuming 180 degrees and after wrapping in a2() seco:nd inner layer of fiber mal;erial, and after wrapping in an extemal film according to Figures 7 and 8 Figure 11 is a perspective representation of a second variant of the process for making a tube i'rom a single fiber strip, with l:he fommation of a central seam by a fusion method without additional material.

Figure 12 is an enlarged cross section through the overlap area of the margins before the seam is made along the line A-A in Figure 11.

Figure 13 is an enlarged cross section through the overlap area during the heating of the mar~iins in the seam area along the line B-B.

Figure 14 is an enlarged cross section through the finished seam area along the line C-C in S Figure 11 .

Figure 15 is a perspective view of a double wedge-shaped electric heater.

~Figure 16 is a perspective view of a double wedge-shaped heater similar to Figure l S, but with gas heating and gas discharge openings disposed flatly.

Figure 17 is a perspective view of a heater configured as a heating noz~le with a slot opening discharging the hot gas in the direction of movement of the tube according to Figure 1 1.
lC;
Figure 18 is a perspective view of a heater configured as a nozzle with a slot opening discharging the hot gas against the direction of movement of the tube.

Figure 19 is a perspective view of a second variant of the process for the production of a tube of two fiber strips of different width, with the formation of two ",a~ginal seams by a fusion process without additional material, with the margins of the narrower fiber strip on top.

Figure 20 is a perspective representation of third variant of the process for producing a tube fTom two fiber strips of different width, with the formation of two marginal seams by a fusion process without additional material, with the margins of the narrower fiber strip on the bottom.

Figure 21 is a c:ross section through an irnpregnatable tube with an internal tube of film, two ZAPFR4s4-~L/ALT
inner layers of fiber strips and one external film, each with two junctions in the dif~renl overlap areas, and ~igure 22 is a prerel.ed application of a l:ube with a cross section similar to Figure 21.

In Figures 1 and 2 there is shown a first supply roll 1 with an inner tube 2 of a l,~nsparent film which can be made with or without seam and is impermeable to curable resins and resistant to them. This inner tube 2 is fed Iying flat to a receiver 3 which is in the form of a continually running conveyor belt 14. The thicknesses shown are not to scale.
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Synchronously therewith, a first fiber strip 6, made firom a fiber material that can be i,l.plegnated with a curable resin and stretched circunlferenlially, is drawn firom a second supply roll 5. The two margins 6a and 6b are folded around the inner tube 2 thereby forming two overlap areaLs 7a and 7b. Into these areas a reactive resin is delivered firom a supply tank 8 15 by means of a proportioning pump and two nozzles 9 and can consist of the same resin that is later used for the impregnation. The resin application can be continuous, or ch~nging or intermittent. Th,e resin is applied in the form of so-called "resin trails" 23 in a width that is less than the width of the overlap areas 7a and 7b and it penetrates partially into the fiber material, which is indicated in Figure 3 by darkening.
Figures 1 and 2 show a horizontal performance of the process and an appa-~lus especially suited for the purpose, which requires little space and above all it can be adapted to different tube di~rneters and different spacing of the overlap areas 7a and 7b.

25 First the first fiber strip 6 is deposited from below onto the horizontal receiver 3, which is in the form of a conveyor belt 14; it comes fi om the supply roll 5 and its width is greater than one-half the ci~culllferellce or width of the inner tube 2 Iying flat. Guide rails 15, whose spacing and pos:ition relative to the receiver 3 can be adjusted independently of one another by hand wheels 16 and lead screws 17, fold the margins 6a and 6b inward around the inner tube 2.

The guide rails ilare funnelwise at their entry end. It is to be understood that an inner tube 2 is not absolutely necessary, so that the fiber strip 6 can be deposited on the receiver 3 and its ",argi~s 6a and l5b can be folded inward thereon, so that fiber material is laid upon fiber material.
s The resin from the supply tank 8 is applied by means of the two nozzles 9 to the upper side of the margins 6a and 6b. A second fiber strip 19 is drawn synchronously from an additional supply roll 18, ~1vhich is omitted from Figure 2; its width corresponds at most to one-half of the cir.;u,nl'elellce or width of the inner tube ,', and it is applied with both its margins down onto 10 the margins 6a a.nd 6b of the first fiber striip 6, resulting in an arrangement according to Figure 5.

Guidance is provided here again by additional guide rails 20 whose distance apart and position with respect to receiver 3 are adjustable independently of one another by hand wheels 21 and feed screws 22. Between the guide rails 20 and above the second fiber strip 19 is a "floating"
pressure plate 40 with a window 40a above which a curing lamp 11 is disposed which hardens the two resin trails 23 through the first fiber strip 6. The pressure plate 40, which is held loosely vertically but locked in horizontal directions, has the purpose of achieving a reliable wetting of the ",largins of the fiber strips 6 and 19, so that an inner layer 12 is formed which is 20 closed on the circun-rerence and forms tog,ether with the inner tube 2 a sandwich which can be transported continuously by conveyor belt 14 in the direction of the arrow 24.

To produce a plurality of inner layers 12 there is the possibility in this case too for passing the sandwich 13, after appropriate readjustment, again or repeatedly through the same apparatus, 25 or to place after it an additional similar apparatus which is already approp"ately adjusted.

It is in that case possible, but necessary only in exceptional cases, for the sandwich 13 of the inner tube 2 and at least one of the previously applied inner layers 12 to be turned 180 degrees before applying the next inner layer, as fo:r example in the upside-down position shown in ZAP~R4~-~L/ALT
Figure 9. Then a second, wider fiber strip 6-2 is applied to the receiver 3 undemeath the sandwich 13 and, after the application of two more resin trails 23-2, covered on top with an additional, narrower fiber strip 19-2 and h,ardened, until the structure shown in Figure 9 has formed, which ii a new sandwich 13-2, the position ofthe resin trails 23 and 23-2 being 5 shifted on the cif~ lference, which is vely clearly shown by Figure 9. The individual thicknesses are shown exaggerated.

Figure 3 shows by means of an enlarged perspective drawing the important elements from Figures 1 and 2 with resin being fed in the fomm of trails 23 by the nozzles 9 onto the already folded lllalgins 6a and 6b of the wider fiber strip 6 before the narrower fiber strip 19 is applied.
This application is perfommed by a guide roller 19a. The wavy shape of the resin trails 23 indicates a traversing movement of the nc~zzles 9 in the direction of the double arrow 9a. The supply roll S is omitted as well as the two guide rails l S and the front guide rail 20. The receiver 3 is represented simplified as a work table. Easily seen is how the lllal~ins 6a and 6b 15 are weighted down by the "floating" pressure plate 40 with the window 40a for admitting the ultraviolet radiation of the curing lamp 11 and upwardly curved leading edge 40b.

The resultant imtermediate product, the inside layer 12, is represented in section in Figure 5, but along with tlhe inner tube 2 which was omitted in Figure 3 and also is not always necessary.

Figure 4 shows, in a perspective similar to Figure 3, the essential elements from Figures 1 and 2, with resin being fed onto the margins, not numbered, of the flat-lying, narrower fiber strip 19 before the margins 6a and 6b of the wider fiber strip 6 are folded over. In Figure 4 the 25 system is prolonged leftward, and also the entrance end of the receiver 3 is shown in conjunction wit]h the supply roll 5 and another guide roller 5a. The procedure of folding the Illalghls 6a and ~Sb of the wider fiber strip 6 around the margins of the narrower fiber strip 19 is very clearly shown, and to some extent the margins 6a and 6b are continuously folded down onto the resin trails 23. The folding process is perfommed in Figure 3 on the left, outside the ZAPl~ R 454 - JEL~ALT
drawing. The guide rails 15 needed for this purpose, with their funnel-like entrance ends (Figures 1 and 2) are also omitted firom Figure 4 for the sake of clarity. The supply roll 18 was for this purpose shifted leftward with the guide roller 19a to the position 18' represented in broken lines, ahead of the nozzles 9, as seen in the direction of the entrance of the fiber strips 6 5 and 19.

The intermediate product resulting therefi om, the inner layer 12, is represented in section in Figure 6, along ~ith the inner tube 2 whic,h was omitted in Figure 4 and also is not always necessary.
It is then especially advantageous if, when an inner tube 2 is used, the latter is affixed to the directly adjacenlt surface of the fiber strip 6, 19, for example by cementing or welding. In this case it is a prefalbricated product which is used in this condition. In this case the inner tube 2 with the rest of 1he components of the cured tube remains in the pipe and does not have to be 15 withdrawn. This has the considerable advantage that the repair tube can be used also for water under pressure and especially for potable water, due to its special impermeability. This is because in the latter case no resin components, solvents, curing agents, accelerators or the like or other resin vapors are transferred to polable water.

20 Figures 7 and 8 .show how the intermedial:e products of Figures 5 and 6 can be wrapped in an exterior film 25 in a wrapping apparatus 37.

The sandwich 1:3 is fed firom the left, either firom a preceding apparatus or firom an intermediate roll not shown. Synchronously a band of initially flat-lying film 27, which is impermeable to 25 the resin and resistant to it, is delivered fn~m below from a supply roll 26 and deposited Oll a conveyor belt 28 under the sandwich 13. The film band has a width that is greater than the circumference or twice the width of the sandwich 13, and its margins are folded by a folding device or guide rails 29 around the sandwich 13 and laid flat, resulting in the formation of an overlap area 30. The guide rails 29 can also be adjusted against one ZAP~R454- ~L~ALT
another and/or in the same direction over the conveyor belt by hand wheels 31 and lead screws 32.

A pressure plate 33 with two central openings 33a and 33b "fioats" on the film band while 5 being held in the horizontal direction. The pressure plate 33 pursues the purpose of a wrinkle-free wrapping ol'the last inner layer 12 and of holding down the overlap area 30.

Beyond the presaure plate 33 is a portal 34 with a welding device 35 with four guide rollers 35a over which ;a welding band 35c is carried, which passes through two heating stations and produces a weld seam 36 (shown darkened in Figure 9). Ahead ofthe portal 34 and within the opening 33b the overlap area 30 is unfolded again over a short length in order to admit a welding shoe 35d which extends rightward underneath the welding band 35c and by which the overlap area 30 iis reclosed by a hold-down not visible. The welding shoe 35d serves to support the welding band 35c and the overlap area 30 of the external film 25. The drive parts 15 are contained in a housing 35e. A welding device of this kind is obtainable commercially and therefore is not iùrther described; its height is adjustable in the direction of the double arrow 38.

A final sandwich 13a is in this manner prepared and is deposited on a pallet 39 to be carried 2~ away.

It is stressed thal~ the inner layer 12 in this case is still "dry," i.e., with the exception of the resin trails 23 and 23-2, it is not impregnated with the curable resin and must be fed to an i".p,~~-a~ ;ng appa,~ s, here not shown, which can be done immediately afterward, or after 25 temporary storag~e, or at a worksite.

A method and an appa,~ s well suited for this purpose are described in DE 196 37 795 Al of the same applica.nt, wherein a complete tube, consisting of an inner tube, a fiber inner layer and an outer tube, is passed through a roller gap, and the still liquid resin is fed into its open end ZAPFR4~-~L/ALT
between the inner tube and the outer tube with the fiber inner layer and is spread through the roller gap. The tube is evacuated ahead o:f the roller gap and pulled in back of the roller gap by pinch rolls, resulting in an end product with a perfect and complete i...pregnalion.

Figure 10 shows a preliminary end product which has been produced in a reversal of the order in which the product in Figure S was prodluced. For this purpose the supply roll 18 was shifted ahead into posit;ion 18' in Figures 1 and 4. Thus the narrower fiber strip 19 was first laid onto the flat-lying inner tube 2 or onto the receiver 3, and then the margins 6a and 6b of the wider fiber strip 6 are fiolded over the margins 1 9a and 1 9b of the narrower fiber strip 19. To apply an additional imler layer, first the sandwich of Figure 6 was rotated 180 degrees, and then two additional fiber strips 19-2 and 6-2 were a.pplied in a manner similar to Figure 9. The intermedi~e prc,duct was then introduced again into an apparatus according to Figures 7 and 8 and wrapped in the outer film 25, so that the "dry" preliminary end product in Figure 10 was obtained.
Also in the following figures the same palts or parts with the same function are provided with the same reference numbers.

In Figure 11 the:re is shown a section of a receiver 3 which is designed as a work table. From a supply roll not shown, a flat-lying inner twbe 2 made of a film is fed to it, but it is not essential to the invention. From another supply roll, not shown, a flat fiber strip 6, initially flat outside of the field of the drawing, is fed and is folded around the two longitudinal edges 2a and 2b of the inner tube 2. Its width is such that, in approximately the middle, an overlap area 7 is formed from bot;h ~.-argins 6a and 6b (Figure 12) of the fiber strip. Between these two margins 6a and 6b there iis a heater 51 which is supplied through a line 60 with a heating gas. The effect involved in this is further explained with the aid of Figures 12 to 14. The portion ofthe fiber strip 6 that is beneath the film tube 2 is represented in broken lines, although it is visible through the film tube 2.

CA 02230806 l998-02-27 ZAPFR-~ALT
In the transport direction (arrow 57) a presser 55, configured as a roller, which can also be cooled if necess~ry, presses against the heated overlap area 7. Thus the fusion bond is solidified within the overlap area 7 without destroying the fiber structure. The work table is provided on bot:h sides with parallel guide rails 20 of which only the rear one is shown, and 5 which can be adjusted to the tube width by hand wheels 21 and feed screws 22.

Figure 12 shows the overlap area 7 with the initially still unbonded margins 6a and 6b of the fiber strip 6 (line A-A in Figure 1 1). The fiber strip 6 consists of two dirrerent fiber materials F1 and F2 with di~rellt fusion temperatures TS1 and TS2. For example, there can be a 10 polyester batting on one side and a glass fiber batting on the other side, which are bonded inseparably together by needling or quilting. In this case - in the overlap area 7 - a polyester batting lies on a glass fiber batting.

According to Figure 13, during transport l;he overlap area 7 rises up (see Figure 11, line B-B) 15 onto a heater 51 which consists of a double wedge-shaped hollow body with gas discharge openings 51 b airned upward and downward (upward in Figure 16). Across the length of the heater 51 there e xtends a gas discharge slot 51c which gives the heater the effect of a flat nozzle. Of course, the top and bottom gas discharge openings 51 b and the gas discharge slot 51 c need not be present together and may be used selectively or alternatively, depending on 20 the direction in ~which the greater part of the heat energy is to be aimed. The individual gas streams running into the depth of the fiber materials are indicated by arrows.

Figure 14 shows, the overlap area 7 after the two margins 6a and 6b have been united beyond the pressing me~ms 55 (roller body) at the line C-C in Figure 1. The bonding point 6g is 25 indicated by a broken rectangle which, however, is not necessarily to scale. Actually, this bonding zone is very thin and flat and is limited to the surface areas of margins 6a and 6b directly superimposed on one another witlhin the overlap area 7. The width "D" of the bonding area 6g is narrower than the overlap area 7. These bonding zones 6g can also be called "melt traces."

--~o--ZA*FR-~ALT
Figure 15 show~, a heater 50 of double-wedge shape whose upper side SOa is roof-like and whose bottom SOb is flat. Electric power lines SOd and a meter conductor SOe are brought through a tubular holder SOc for a thermocouple which is disposed within the heater 50 and connected to a controller. In this case regular contact heating is involved. At least the leading 5 edge SOf can also be rounded.

Gas heaters and air heaters are represented in the following figures.

Figure 16 shows" in a manner similar to Figure 15, the double wedge-shaped heater 51 already 10 ~li$cu$~ed in Figure 11, with gas discharge openings 51b arranged in a regular pattern on its upper side 50a.

Figure 17 shows a heater 52 configured as a heating nozzle with a nozzle slot 52a discharging the hot gases (arrows) in the direction of the movement of the tube.
Figure 18 shows a heater 53 configured as a heating nozzle with a nozzle slot 53a discharging the hot gases (arrow~s) against the direction of the movement of the tube.

The planes of symmetry of the nozzle slots 52a and 53a can be raised up or down with respect 20 to a plane paralh~l to the surfaces in contact ofthe ...algins 6a and 6b, in the direction ofthe double arrows "]P", in order to influence the distribution of energy. Thus it is possible, for example, for the fiber strip surface with the greater proportion of polymer fibers to be heated more strongly than the fiber strip surface with the greater proportion of mineral fibers.

The heaters 51, :52 and 53 assume from the gas temperature a surface temperaturecorresponding thereto, so that here in the overlap area 7 the gas heating results in contact heating. It has surprisingly been found that in none of the cases does adhesion occur between the heater and thle fiber material. If desired, thermally insulated spacers can also be provided between at least one of the fiber strips and. at least one of the heater surfaces.

ZAPF R - JEUALT
Figure 19 explains an additional variant of the conduct of the process for making a tube out of two fiber strips ~5 and 19 of different width, with the formation of two overlap areas 7a and 7b with the ,l,a,~;ins ofthe narrower fiber strip 19 on top. The margins 6a and 6b ofthe wider fiber strip are first folded around the film tube 2 as in Figures 1 and 2, but in this case they 5 leave a wide dis tance E between the inwardly facing cut edges 6e, 6f of the wider fiber strip 6.
The cut edges 1 9a and 1 9b of the narrower strip 19 which are Iying free on top are facing outward, so that the two heaters 51 enter i'rom the outside into the overlap areas 7a and 7b. In this case two pressers 55 and 56 in the form of rollers or wheels follow behind the two heaters 51.
lC~
Figure 20 explains an additional variant of the process for making a tube out of two fiber strips 6 and 19 of diffe:rent width, with the form;ation of two overlap areas 7a and 7b with the margins of the narrower filber strip 19 on the botto,m. In this case first the narrower fiber strip 19 is laid upon the film tube 2 and the wider fiber sltrip 6 is then folded around the film tube and the 15 narrower fiber sl:rip 19, but in this case ag'ain it again leaves a wide distance E between the inwardly facing cut edges 6e and 6f of the wider fiber strip 6. The cut edges 6e and 6f Iying free on top are turned inward so that the two heaters 51 are inserted from the inside into the overlap areas 7a and 7b. This creates the .advantage that the two heaters 51 can be supplied with hot air through a central supply line 61. Otherwise nothing is basically different in the 2~ procedure.

The process according to Figure 1 1 on the one hand and Figures 19 or 20 on the other can be combined with one another in order, for example, to be able to arrange a plurality of tubes concentrically without having the overlap areas coincide resulting in an undesired local and 25 additive thic~n-ing It is obvious thal: measures and designs according to Figures 1 to 4 on the one hand and Figures 11, 19 and 20 on the other can also be interchanged. Thus, in Figures 1 to 4, the resin nozzles 9 and the curing lamps 11 can be replaced with heaters 50 to 53 and pressers 55 and ZAPFR-~ALT
56, and in Figures 11, 19 and 20 the heaters 50 to 53 and the pressers 55 and 56 can also be replaced with resin nozzles 9 and curing lamps 11. Also, a wrapping appa,~l~ls 37 can be added to the appa.al.ls of Figures 1 1, 19 and 20 for a tube of film 25 according to Figures 7 and 8, so that the res.ult is again the products of Figures 9 and 10.

The adjustability of the guide rails 15 and 20 serve not only for adaptation to different widths of the flat-lying tube, but also for shifting it laterally with respect to the supply rolls 5, 18 and 18'. As an alten~ative, the supply rolls 5 and 18-18' can be made displaceable together or also cont-~, iwise in the transverse direction wiith respect to the receiver 3, or supply rolls of wider 10 or narrower fiber strips can be used. In this case additional fiber strips can be fed in order to build up a multiple inner layer 12, without the need for turning after the first sandwich 13 is made.

Figure 21 shows such an application: the fiber strips 6 and 19 were treated in a way similar to 15 the process either on an apparatus according to Figures 1 and 2 or on one according to Figure 20, which led to an intermediate product according to Figure 5, but with the difference that in both of the lateral overlap areas 7a and 7b two parallel bonds (resin or fusion traces) were applied. A sandwich of this kind can then be introduced without turning, instead of the inner tube 2, into an apparatus similar to Figures 7, 8 or 11. Only the fiber strip is then to be 20 replaced by a fiber strip 6-3 whose width is more than twice that of the flat-lying sandwich, so that a single bro;ad overlap area 7 is formed, which is likewise held together by two junctions 63.

The apparatus and the guidance of the material then appear somewhat like the left halves of 25 Figures 7 and 8. Only instead ofthe film ;and the welding device 35, there is again the fiber strip 6-3, a supply tank 8 with two resin nozzles 9 and a curing lamp 11 which in this case are disposed above lthe middle overlap area 7.

Alternatively, the bonding technology according to Figures 11 to 20 can be applied. It can ZAPFR-~ALT
easily be seen th,at the overlap areas 7, 7a and 7b with the junctions (resin or fusion traces) 62 and 63 are arranged offset from one another on the circumference, so that no bulges occur.
The intermediate product of Figure 21, wlhich is again a sandwich, can then be further worked by one of the already described methods, for example in appa,~ s according to Figures 7 and 8. In the latter t,he film tube 25 is applied with an overlap area 30 and two weld seams 64.

Figure 22 then shows a cross section through an egg-shaped sewer pipe with a repair tube 65 which when lying flat is very much the same as in Figure 21. A dash-dotted fold line 66 of the cross section is represented, and care must be taken that no junctions (resin or fusion traces) and, if possible no overlap areas 7, 7a, 7b, 30 lie on this fold line.

The following materials and dimensions are involved:

Inner tube 2 and outer film 25:
l S polyester, polyethylene, polypropylene, polyamide and l~min~tes thereof.
Thickness of the inner tube 2: 0.100 to 0.'200 mm Thickness of the outer film 25: 0.1'50 to 0.300 mm Elasticity/elastic: limit up to 30%.
Fiber strips 6, 6-2, 6-3, 19,19-2 batting, wovens, rovings, and cuttings thereof, fibers of polyester, polyethylene, polypropylene, acrylic, polyamide, glass, also in mixture and inlaid with threads.
Thickness: 1.0 to 8.0 mm, preferably 2.0 to 4.0 mm per inner layer Elasticity/elastic limit up to 15%.

Resins:
Polyester, epoxy and vinyl ester resins, for example "Palatal" of BASF in Ludwigshafen, " 4 ZAPF R - JEIJALT
Germany, with a~ctivators and accelerators for curing by ultraviolet light, resins curing cold and warm.

Diameter of the finished tube: up to more than 1200 mm.

Claims

1. Method for manufacturing a tube for lining pipelines and sewer systems with at least one inner layer (12) consisting of a fiber material impregnatable with a curable resin, the margins (6a, 6b) of which are provided with at least one overlap area (7, 7a, 7b) running lengthwise, fixedly bonded on the circumference of the tube by superimposition on an equal (6, 6-3) or another fiber strip (19, 19-2), and which is then surrounded with an external film (25) that is impermeable to the resin, characterized in that a) at least one fiber material elastically expandable in the circumferential direction is used for the at least one inner layer (12), and that b) the margins (6a, 6b) of the inner layer (12) are irreversibly bonded together either continuously or section-wise at junctions (6g, 62, 63) in the overlap area (7, 7a, 7b), either by b1) placing a curable resin in the overlap area (7, 7a, 7b) between the margins (6a, 6b) and, after at least partial penetration into both margins (6a, 6b), curing it by actinic radiation through the fiber material, or by b2) partially fusing the fiber material of at least one of the margins (6a, 6b) superficially in the overlap area (7, 7a, 7b), and then fusing the margins (6a, 6b) together with the application of pressure.

2. Method according to claim 1, characterized in that, as the curable resin for bonding the margins (6a, 6b) of the inner layer (12), the same resin is used as for the impregnation of the remaining cross section of the inner layer (12).

3. Method according to claim 1, characterized in that the junction(s) (6g, 62, 63) is/are narrow circumferentially of the tube in proportion to the width of the particular overlap area (7, 7a, 7b).

4. Method according to claim 1, characterized in that in at least one of the overlap areas (7, 7a, 7b) at least two junctions (6g, 62, 63) are produced.

5. Method according to claim 1, characterized in that the at least one inner layer (12) is placed around an inner tube (2) impermeable to the resin, and that after its application the resin of the at least one overlap area (7, 7a, 7b) is cured by actinic radiation.

6. Method according to claim 1, characterized in that the at least one inner layer (12) consisting of fiber material is formed of two fiber strips 96, 6-2, 19, 19-2) of which one is wider than half the circumference of the inner tube (2) and the other has no more than the same width as half the circumference of the inner tube 92), that first the wider fiber strip (6, 6-2) is delivered onto a receiver (3) and is folded inward with both its margins (6a, 6b), that the narrower fiber strip (19, 19-2), either before or after the folding of the wider fiber strip (6, 6-2) is laid upon the same receiver (3) with the creation of two overlap areas (7a, 7b) of the two margins (6a,6b), while either b1) a curable resin is placed between the margins (6a, 6b) in both overlap areas (7a, 7b) and, after the at least partial penetration into the superimposed margins (6a, 6b), it is cured by actinic radiation through the fiber material, or b2) the fiber material of each one of the margins (6a, 6b) is partially fused superficially, whereupon the margins (6a, 6b) are fused together with the application of pressure.

7. Method according to claim 1, wherein the fiber material of at least one of the margins (6a, 6b) is partially fused superficially in the overlap area (7, 7a, 7b), whereupon the margins (6a, 6b) are fused together with the application of pressure, characterized in that a) at least 50% of the at least one fiber strip (6, 6-2, 19, 19-2) on opposite surfaces is selected from different fiber materials (F1, F2) with different melting temperatures (TS1, TS2), b) in each overlap area (7, 7a, 7b) the margins (6a, 6b) of one fiber material (F1) with a lower melting temperature (TS1) and of one fiber material (F2) with a higher melting temperature are laid one on the other, and that c) in each overlap area (7, 7a, 7b) at least one of the directly adjacent surfaces is heated at its contact surfaces to a temperature that is between the melting temperatures (TS1, TS2) of the two fiber materials.

8. Method according to claim 7, characterized in that, between the margins of the fiber strips (6, 6-2, 19, 19-2), a hot gas is injected at a temperature that is between the melting temperatures (TS1, TS2) of the two fiber materials.

9. Method according to claim 7, characterized in that the temperature (TG) of the hot gas is selected such that the fiber material (F1) with the lower melting temperature (TS1) melts with local limitation to its surface and bonds itself to the non-melting fiber material (F2) with the higher melting temperature.

10. Method according to claim 7, characterized in that at least one fiber strip (6, 6-2, 19, 19-2) is used whose surface consists at least predominantly of thermoplastic fibers and whose other surface consists at least predominantly of mineral fibers.

11. Method according to claim 7, characterized in that at least one fiber strip (6, 6-2, 19, 19-2) is used, which consists of a sandwich of a first mat of plastic fibers from the group polyester fibers, polyamide fibers and acrylic fibers, and of a second mat of glass fibers.

12. Method according to claim 11, characterized in that at least one fiber strip (6, 6-2, 19, 19-2) is used in which the two mats are bonded together broadly by needling stitching or quilting.

13. Method according to claim 11, characterized in that a fiber strip (6, 6-2, 19, 19-2) is used in which the fibers of the glass fiber mat are provided with a resin-friendly surface coating.

14. Method according to claim 8, characterized in that, for the injection of the hot gas an at least single wedge-shaped heater (51, 52, 53) is used, which has at least in that surface (51a) gas discharge openings (51b) which is in contact with that surface of the fiber strip (6, 6-2, 19, 19-2) which has the component with the lower melting temperature (TS1).

15. Method according to claim 7, characterized in that the width "B" of the junction(s) (6g, 62, 63) is narrow in the circumferential direction of the tube in proportion to the overlap area (7, 7a, 7b).

16. Method according to claim 7, characterized in that the junctions (6g, 62, 63) of the tube are welded. in their flat-lying state and after welding are solidified by a pressing means (55, 56) whose mantle lines run parallel to the boundary surface between the flat-lying margins (6a, 6b).

17. Method according to claim 1, characterized in that at least two inner layers (12) consisting of fiber material are produced on the receiver (3), and that the first inner layer 912) is turned 180° before the application of the second and each additional inner layer (12).

18. Method according to claim 16, characterized in that, in the construction of a tube of more than two inner layers (12) of fiber material, the positions of the overlap areas (7, 7a, 7b) are distributed on the circumference of the tube by relative transverse shifting of fiber strips (6, 6-2, 19, 19-2).

19. Method according to claim 1, characterized in that for finishing the tube is enveloped in an external film (25) which has a width that is greater than the circumference of the last inner layer (12) consisting of fiber material, and that the external film (25) is folded around the at least one inner layer (12) with the formation of an overlap area (30), and is welded in the overlap area (30).

20. Tube for the impregnation and lining of pipelines and sewer systems, having at least one inner layer (12) consisting of a fiber material impregnatable with a curable resin, whose margins (6a, 6b) are provided with at least one overlap area (7, 7a, 7b) by superimposition on an equal (6, 6-2) or another fiber strip (19, 19-2) on the circumference of the tube and are surrounded by an external film (25) impermeable to the resin, characterized in that a) the at least one inner layer (12) consists of at least one fiber strip (6, 6-2, 19, 19-2) which is elastically expandable at least in the circumferential direction of the tube, and that b) the margins (6a, 6b) of the inner layer (12) are joined irreversibly together either continuously or by sections by a thermal process, while either b1) the overlap area (7, 7a, 7b) is bonded between the margins (6a, 6b) by a cured resin which has penetrated at least partially into both margins (6a, 6b), or b2) the fiber material of at least one of the margins (6a, 6b) is partially melted superficially in the overlap area (7, 7a, 7b) and is fused with the other margin(6a, 6b).

21. Tube according to claim 20, characterized in that the junction(s) (6g, 62, 63) is/are narrow in the tube's circumferential direction in proportion to the width of the overlap area (7, 7a, 7b).

22. Tube according to claim 20, characterized in that the at least one inner layer 912) consisting of fiber material is composed of two fiber strips (6, 6-2, 19,19-2), one of which is wider than half the circumference of the inner tube (2) and the other is of no more than the same width as half the circumference of the inner tube (2), that the narrower strips (19, 19-2) with its two margins either above or beneath the margins (6a, 6b) of the wider fiber strip and forms two overlap areas (7a, 7b).

23. Tube according to claim 20, characterized in that a) the at least one fiber strip (6, 6-2, 19, 19-2) consists on opposite surfaces of at least 50% of different fiber materials (F1, F2) having different melting temperatures (TS1, TS2), b) in each, overlap area (7, 7a, 7b) tlhe margins (6a, 6b) of one fiber material (F1) of a lower melting temperature (TS1) and of a fiber material (F2) with a higher melting temperature (TS2) are placed one on the other and bonded together.

24. Tube according to claim 23, characterized in that the one surface of the fiber strip consists at least predominantly of thermoplastic fibers and the other surface at least predominantly of mineral fibers.

25. Tube according to claim 23, characterized in that the at least one fiber strip (6, 6-2, 19, 19-2) consists of a sandwich material composed of a first mat of plastic fibers from the group polyester fibers, polyamide fibers and acrylic fibers and of a second mat of glass fibers.

26. Tube according to claim 25, characterized in that the two mats are bound face-to-face to one another by needling stitching or quilting.

27. Tube according to claim 20, characterized in that, if an inner tube (2) is used the latter is fixedly bonded to the directly confronting surface of the fiber strip (6, 19) in question.

28. Apparatus for manufacturing a tube with at least one inner layer (12) consisting of at least one impregnatable fiber strip (6, 6-2, 19, 19-2) for the lining of pipelines and sewer systems, having an at least substantially horizontal receiver (3) and a transport system for carrying the tube, having at least one supply roll (5,18) with an impregnatable fiber strip (6, 6-2, 19, 19-2) which can be fed to the receiver (3), and having systems for folding the strip margins (6a, 6b), characterized by a) a guidance system for the formation of at least one overlap area (7, 7a, 7b) lying above the receiver (3) by folding the margins (6a, 6b) of the at lest one fiber strip (6, 6-2) and by either b1) at least one nozzle (9) for the application of at least one resin trail of a resin curable by actinic radiation exclusively in the at least one overlap area (7, 7a, 7b) between the overlapping margins (6a, 6b), as well as by at least one actinicradiator (11) disposed opposite the resin trails (23) for the formation of an inner layer (12) closed on the circumference, or b2) at least one heating body (50, 51, 52, 53, 54), which is introducible into the at least one overlap area (7, 7a, 7b) and by which the fiber material of at least one of the margins (6, 6b) is partially fusible superficially to produce a fusion bond, as well as by at least one pressing system (55,56) for compressing the fusion bond, as well as by c) a wrapping apparatus (37) for wrapping the at least one inner layer (12) in an external film (25).

29. Apparatus according to claim 28 for producing a tube with at least one inner layer 912) consisting of two impregnatable fiber strips (6, 6-2, 19, 19-2), having a plurality of supply rolls (5, 18) with the impregnatable fiber strip (6, 6-2, 19, 19-2), characterized by a) two supply rolls (5, 18) with variously wide fiber strips (6, 6-2, 19, 19-2), of which the wider fiber strip (6,6-2) of which can be fed from below and the narrower fiber strip (19, 19-2) can be fed from above, b) a guidance system for the formation of two overlap areas (7a, 7b) lying above the receiver (3) by folding the margins (6a, 6b) of the wider fiber strip (6, 6-2) with respect to the margins of the narrower fiber strip (19, 19-2).

30. Apparatus according of claim 28, characterized in that the receiver (3) consists of a conveyor belt (14) and the guidance system for the folding of the margins (6a, 6b) of the wider fiber strip (6, 6-2) consists of first guide rails (15) which are disposed above the conveyor belt (14) and are adjustable independently of one another across the running direction of the conveyor belt (14).

31. Apparatus according to claim 30, characterized in that behind the first guide rails 915) two guide rails (20) are disposed above the conveyor belt (14), which are adjustable independently of one another across the running direction of the conveyor belt (14).

32. Apparatus according to claim 28, characterized in that the at least one nozzle (9) for the application of at least one resin trail (23) is disposed between the first (15) and the second guide rails (20).

33. Apparatus according to claim 31, characterized in that between the two guide rails (20), for the purpose of holding down the margins of the at least one fiber strip (6, 6-2, 19, 19-2) in the at least one overlap area (7, 7a, 7b) at least one pressure plate (40) with at least one window (40a) is disposed, above which at least one actinic radiator (11) for the at least one resin trail (23) is situated.

34. Apparatus according to claim 28, characterized in that the wrapping system (37) has a conveyor belt (28) above which guide rails are present in a mirror-image arrangement for the folding of a film strip (27) for bonding the margins (27a, 27b) of the external film (25) and are adjustable independently of one another across the running direction of the conveyor belt (28).

35. Apparatus according to claim 34, characterized in that between the guide rails (29) a pressure plate (33) is disposed for holding down the margins (27a, 27b) of the film strip (27) in the overlap area (30), and behind it a welding device (35) is situated for production of a welded seam (36) in the overlap area (30) of the conveyor belt (27).