Note: Descriptions are shown in the official language in which they were submitted.
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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,
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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
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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.
--6--
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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,
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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
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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_
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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< 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~
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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-
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~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.
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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
-I3-
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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.
1~
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.
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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
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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
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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
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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
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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.
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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--
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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.
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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
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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
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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
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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.
