DK172367B1

DK172367B1 - Method and apparatus for coating pipes

Info

Publication number: DK172367B1
Application number: DK082790A
Authority: DK
Inventors: Wayne Keith Buttimore; Douglas Thomas Mullen
Original assignee: British Pipe Coaters; Bredero Price Services
Priority date: 1987-10-14
Filing date: 1990-04-02
Publication date: 1998-04-20
Also published as: CA1318819C; GB2231511A; NO174458B; EP0380474A1; GB2231511B; NO174458C; GB9006509D0; DK82790A; NO901668D0; DK82790D0; NO901668L; EP0380474B1; WO1989003289A1

Description

i DK 172367 B1in DK 172367 B1

FREMGANGSMÅDE OG APPARAT TIL BEKLÆDNING AF RØRMETHOD AND APPARATUS FOR CLOTHING PIPES

Denne opfindelse vedrører beklædning af rør af den slags, der anvendes til underjordiske eller undervands-rørlednin-5 ger til transport af olie, gas, slam eller lignende materialer, der kan fremføres i rør fra en underjordisk kilde. Især vedrører den rør, ved hvilke en stålrørssektion belægges med en antikorrosionsbelægning og derefter med en opdriftsmodvirkende belægning af betonblanding (herefter kal-10 det betonbelægning). Sådanne rør har normalt en forskyd-ningskraftoptagende indretning i form af trådviklinger eller net anbragt om antikorrosionsbelægningen før pålægning af betonbelægningen. Dette modvirker betonbelægningens tendens til at glide eller springe af det antikorrosionsbelag-15 te rør under udlægningsarbejdet, hvilket kan give betragtelige bøjningsspændinger i røret.This invention relates to the lining of pipes of the kind used for underground or underwater pipelines for transporting oil, gas, sludge or similar materials which can be fed into pipes from an underground source. In particular, it relates to pipes in which a steel pipe section is coated with an anti-corrosion coating and then with an anti-buoyancy coating of concrete mixture (hereinafter referred to as concrete coating). Such pipes usually have a shear-absorbing device in the form of wire windings or nets placed on the anti-corrosion coating prior to application of the concrete coating. This counteracts the tendency of the concrete coating to slip or break off the anti-corrosion-coated pipe during the laying operation, which can cause considerable bending stresses in the pipe.

Der kan henvises til følgende patenter US 3 955 600 og GB 1 504 051/2, som er repræsentative for den kendte teknik.Reference is made to the following patents US 3,955,600 and GB 1,504,051/2, which are representative of the prior art.

2020

Typisk bringes hvert rør til at rotere om sin længdeakse og føres i længderetningen gennem en betonbeklædningsstation, hvori beton/tilslagsmateriale bringes til at ramme det roterende rør og derved opbygge et lag beton på røret, så det 25 danner en belægning. Normalt, når der bruges en vikling af trådnet (herefter kaldet tråd), er det nødvendigt at fastgøre en ende af tråden til rørets forreste ende, før det roteres og føres forbi betonbelægningsstationen. Når røret således føres frem, tilføres tråden på kontinuert måde i en 30 passende vinkel for at muliggøre, at rørets rotation bevirker opvikling af tråd over hele rørets længde. Når denne rørsektion er passeret igennem stationen, skal tråden afskæres og fastgøres til rørsektionens bageste ende. Dette har adskillige ulemper, som omfatter en produktionshastig-35 hed, der er mindre end ønskelig, på grund af behovet for at standse røret før og efter betonbelægningsstationen for at DK 172367 Bl 2 fastgøre tråden, som ellers ville udvise en "urfjeder-virkning" og frigøre sig selv under belægningen til en afslappet vikling uden den ønskede funktion. Endvidere kan processen ikke uden videre automatiseres på grund af behovet 5 for at have personale, der skal sørge for fastgørelsen af tråden ved begge ender af røret. Endvidere er det ikke ønskeligt at have en fri trådende, der direkte kontakter antikorrosionsbelægningen på stålrøret, eftersom den er tilbøjelig til ved slidende kontakt at gennemtrænge denne 10 belægning og forårsage korrosionsangreb, som kan svække og i sidste ende forårsage førtidige fejl og behov for ud skiftning af denne rørsektion.Typically, each tube is caused to rotate about its longitudinal axis and is passed longitudinally through a concrete cladding station, wherein concrete / aggregate material causes the rotating tube to hit and thereby build a layer of concrete on the tube to form a coating. Usually, when using a wire mesh winding (hereafter referred to as wire), it is necessary to attach one end of the wire to the front end of the pipe before it is rotated and passed past the concrete coating station. Thus, as the tube is advanced, the wire is fed in a continuous manner at a suitable angle to allow the rotation of the tube to effect winding of wire over the entire length of the tube. Once this pipe section has passed through the station, the thread must be cut off and attached to the rear end of the pipe section. This has several drawbacks which include a production rate less than desirable due to the need to stop the pipe before and after the concrete paving station in order to secure the wire which would otherwise exhibit a "clock spring effect" and freeing itself during the coating to a relaxed winding without the desired function. Further, the process cannot be automated simply because of the need 5 to have staff responsible for securing the thread at both ends of the tube. Furthermore, it is not desirable to have a free thread that directly contacts the anti-corrosion coating on the steel pipe, since it tends to penetrate this coating upon abrasion and cause corrosion attacks which can weaken and ultimately cause premature failure and need for replacement. of this pipe section.

Derfor er det et formål med denne opfindelse at undgå eller 15 formindske de forannævnte ulemper ved at frembringe en fremgangsmåde til belægning og et apparat til udførelse af fremgangsmåden, som frembyder flere fordele i forhold til kendt teknik, herunder muligheden for forøgelse af produktionshastigheden, muligheden for automatisering af belæg-20 ningsstationen, formindskelse af personalebehovet og minimering af trådkontakt med antikorrosionsbelægningen.Therefore, it is an object of this invention to avoid or mitigate the aforementioned disadvantages of providing a coating method and apparatus for carrying out the method which offers several advantages over prior art, including the possibility of increasing the production rate, the possibility of automating the coating station, reducing staffing requirements, and minimizing wire contact with the anti-corrosion coating.

Følgelig anviser denne opfindelse i sit bredeste aspekt en fremgangsmåde til belægning af rørsektioner, bestående i 25 fremføring af en serie rørsektioner gennem en betonbelægningsstation, hvilken har midler til at rotere og fremføre rørene i deres længderetning, og er kendetegnet ved, at der på stationen findes midler til kontinuerligt at fremføre en tråd til de roterende rørsektioner på en sådan måde, at li-30 nen, der er fremført til sektionerne, bringer tråden i en position til vikling omkring sektionerne og ligger over den viklede tråd over hele dens længde, og skæremidler, der samvirker med trådfremføringsmidlerne, til automatisk at overskære tråden ved forudbestemte tidsintervaller, hvorved 35 linen ved udførelse af fremgangsmåden først tilføres til forenden af det roterende rør og vikles om dette med til- DK 172367 B1 3 strækkelige vindinger til at fastgøre den, så trækkes tråd ind for at påbegynde viklingen omkring røret under påføringen af betonbelægningen i stationen, og tråden afskæres derefter, mens den fremføres, for at forhindre viklingen i 5 at strække sig ud over den betonbelagte del af rør sekt ionen, medens linen fortsætter med at blive viklet omkring den bageste ende af røret.Accordingly, this invention, in its broadest aspect, provides a method for coating pipe sections comprising passing a series of pipe sections through a concrete pavement station which has means for rotating and advancing the pipes in their longitudinal direction and characterized in that the station exists means for continuously feeding a wire to the rotating tube sections in such a way that the line advanced to the sections brings the wire into a winding position around the sections and is over the wound wire over its entire length, and cutting means cooperating with the wire feed means to automatically cut the wire at predetermined time intervals, whereby the line is first applied to the front end of the rotary tube and wound therewith with extensible windings to secure it, then pulled thread to begin winding around the tube during applications n of the concrete pavement in the station, and the wire is then cut off as it is advanced to prevent the winding from extending beyond the concrete-coated portion of the pipe section, while the line continues to be wound around the rear end of the pipe.

Således opnås formålet med opfindelsen ved, at linen tjener 10 til at fastgøre den forreste og den bageste ende af trådviklingen for at undgå at skulle binde tråden manuelt til røret, trådskæring opnås automatisk uden behov for at standse rørsektionernes fremføring, og fremgangsmåden egner sig umiddelbart til automatisering, hvorved fremføringsha-15 stigheden for tråden sammen med afskæringsintervallerne kan beregnes, og stationen indstilles til at vikle tråd under betonbelægningstrinnet. Dette har den fordel, at tråden følger linen under det indledende trin af betonbelægning, hvorved selve tråden ikke kommer i kontakt med rørsektio-20 nen, men bliver indlejret i betonen, der samler sig på røret for at udgøre vægtbelægningen.Thus, the object of the invention is achieved by the fact that the line serves to fasten the front and rear ends of the wire winding to avoid having to bind the wire manually to the tube, wire cutting is achieved automatically without the need to stop the tube sections feeding, and the method is immediately suitable for automation, whereby the feed rate of the wire together with the cut intervals can be calculated and the station set to wrap wire during the concrete coating step. This has the advantage that the wire follows the line during the initial stage of concrete coating, whereby the wire itself does not come into contact with the pipe section but becomes embedded in the concrete which collects on the pipe to constitute the weight coating.

Fortrinsvis omfatter fremgangsmåden anvendelse af trådformningsmidler til at muliggøre forformning af tråden og give 25 den en kurvning, så den let passer til rørsektionens omkreds. Dette letter vikling og tillader brug af billig line, eftersom det kræver mindre kraft til at fastgøre tråden til røret, så det er muligt at anvende forskellige syntetiske fibre eller forholdsvis fin, tynd tråd til dette for-30 mål.Preferably, the method comprises the use of wire forming means to enable preforming of the wire and to give it a curvature so as to easily fit the perimeter of the pipe section. This facilitates winding and allows the use of inexpensive line since it requires less force to attach the wire to the tube so that it is possible to use various synthetic fibers or relatively fine, thin wire for this purpose.

Fordelagtigvis føres hver rørsektion bort fra belægningsstationen med en accelereret hastighed i forhold til gennemgangshastigheden i belægningsstationen, hvorved linen 35 overrives mellem sektionerne.Advantageously, each tube section is moved away from the coating station at an accelerated rate relative to the throughput rate in the coating station, whereby line 35 is overlaid between the sections.

DK 172367 B1 4DK 172367 B1 4

Apparatet, der skal indbygges i en station til belægning af roterende rørsektioner med beton, består af en første fremføringsmekanisme til at afgive en line fra et passende, udskifteligt forråd af dette tilstrækkeligt til at give en i 5 det væsentlige kontinuerlig fremføring af line til rørene, der skal belægges i denne station; en anden fremføringsmekanisme anbragt nær ved den første og indrettet til at fremføre tråd fra et passende udskifteligt forråd af dette tilstrækkeligt til at sikre en kontinuerlig fremføring af 10 tråd på en måde, så den kommer i kontakt med linen, hvorved den efterfølgende bringes til at kontakte og danne en vikling omkring den roterende rørsektion, mens der pålægges beton derpå; og en skæreenhed til at begrænse længden af tråd, der skal vikles omkring rørsektionen.The apparatus to be built into a station for coating rotating pipe sections with concrete consists of a first feeding mechanism for dispensing a line from a suitable, interchangeable supply thereof sufficient to provide a substantially continuous feeding of line to the pipes. this station must be occupied; a second feed mechanism located adjacent to the first one and arranged to feed wire from a suitable interchangeable stock thereof sufficiently to ensure a continuous feed of 10 wire in contact with the line, thereby bringing it into contact forming a winding around the rotating pipe section while applying concrete thereon; and a cutting unit for limiting the length of wire to be wound around the pipe section.

1515

Skæreenheden kan være en guillotinekonstruktion.The cutting unit may be a guillotine construction.

Fortrinsvis samvirker trådfremføringsmekanismen med trådformningsmidler, som forformer tråden til en kurvet udform-20 ning, som passer til rørets omkreds.Preferably, the wire feed mechanism cooperates with wire forming means which preform the wire into a curved shape which fits the circumference of the tube.

Den første fremføringsmekanisme omfatter fortrinsvis også et antal ruller monteret i serie, mellem hvilke linen føres på serpentineagtig måde, og af hvilke mindst en kan bevæges 25 i forhold til de andre for at forøge eller formindske spændingen, der påføres på linen.Preferably, the first feeding mechanism also comprises a plurality of rollers mounted in series, between which the line is guided in a serpentine manner and at least one of which can be moved relative to the others to increase or decrease the tension applied to the line.

Den anden fremføringsmekanisme omfatter fortrinsvis et par modroterende ruller monteret parallelt og med gensidig af-30 stand for at tillade sammenhængende passage af tråd derimellem, af hvilke mindst en er drevet af en motor til at udgøre et middel til at fremføre tråd gennem fremføringsmekanismen; et yderligere par af samvirkende modroterende ruller med skæreelementer på overfladen, som muliggør, at 35 tråd, der passerer mellem rullerne, kan overskæres mellem skæreelementerne med forudbestemte intervaller; og et antal 5 DK 172367 B1 ruller anbragt således, at der fremkommer mindst en reaktionsflade, mod hvilken tråden kan formes i en kurve ved styret tryk, der udøves af mindst en yderligere rulle anbragt på den anden side af tråden.Preferably, the second feeding mechanism comprises a pair of counter-rotating rollers mounted in parallel and mutually spaced to permit continuous thread passage therebetween, at least one of which is driven by a motor to constitute a means for feeding thread through the feed mechanism; a further pair of cooperating counter-rotating rollers with cutting elements on the surface which allows threads passing between the rollers to be cut between the cutting elements at predetermined intervals; and a plurality of rolls arranged so as to provide at least one reaction surface against which the thread may be formed in a controlled pressure curve exerted by at least one additional roll placed on the other side of the thread.

5 I det mindste en rulle i hvert par kan forsynes med midler til at justere gensidig afstand mellem de sammenparrede ruller for tilpasning til forskellige trådtykkelser og for ændring af trykket, der påføres af rullerne.5 At least one roll in each pair may be provided with means for adjusting mutual distance between the mating rollers for adaptation to different thread thicknesses and for changing the pressure applied by the rollers.

1010

Det foretrækkes, at rullerne drives med kæde og kædehjulstransmission med elektromotorer. I tilfældet med skærerul-leindretningen er det nødvendigt at indsætte en kobling til at udkoble disse ruller under vikling af tråd over rørsek-15 tionens længde og begrænse skæreoperationen til kort før viklingen af tråd på rørsektionen afsluttes. Ved skærerullerne foretrækkes det også, at trækket transmitteres fra en rulle til den anden ved tandhjulsindgreb for at synkronisere skæreelementernes funktion. Skæreelementerne er for-20 trinsvis udformet og anbragt på rulleoverfladerne, så de giver en guillotineagtig skærefunktion.It is preferred that the rollers be driven by chain and sprocket transmission by electric motors. In the case of the cutting roller assembly, it is necessary to insert a clutch to disengage these rollers during winding of wire over the length of the pipe section and limiting the cutting operation to shortly before the winding of wire on the pipe section is terminated. At the cutting rollers, it is also preferred that the pull is transmitted from one roll to the other by gear engagement to synchronize the operation of the cutting elements. The cutting elements are preferably formed and arranged on the roller surfaces to provide a guillotine-like cutting function.

Opfindelsen vil nu blive forklaret nærmere med henvisning til de medfølgende tegninger på hvilke: 25The invention will now be explained in more detail with reference to the accompanying drawings, in which:

Fig. 1 er en skematisk sideprojektion af apparatet til at vikle en tråd på et rør ved en betonbelægningsstation, hvorved drivanordningen og understøtningskonstruktionen er udeladt for lettere at 30 kunne vise hovedkomponenterne i fremføringsmeka nismen; fig. 2 er en planprojektion af apparatet og viser detaljer af apparatets drivmekanismer; fig. 3 er et skematisk billede af den ene ende af et rør 35 DK 172367 B1 6 belagt ved fremgangsmåden ifølge opfindelsen; og fig. 4 er en planprojektion af et stykke af trådnettet, som kan pålægges med fremgangsmåden ifølge opfin-5 delsen.FIG. 1 is a schematic side elevation of the apparatus for wrapping a wire on a pipe at a concrete paving station, thereby omitting the driving device and the supporting structure for easier display of the main components of the feed mechanism; FIG. 2 is a plan view of the apparatus showing details of the apparatus's drive mechanisms; FIG. 3 is a schematic view of one end of a pipe coated by the method of the invention; and FIG. 4 is a plan view of a piece of the wire mesh which can be applied by the method according to the invention.

Med henvisning til fig. 1 og 2 beskrives nu et trådviklingsapparat til brug på en station til belægning af rør-sektioner 1, som allerede har fået en antikorrosionsbelæg-10 ning (som for eksempel epoxyharpiks), med beton, i hvilken disse sektioner føres i serie forbi en betonsprøjteindret-ning (ikke vist) på en dreven rulletransportør vist skematisk alene ved rullerne 2. Over denne sprøjteindretning er der anbragt en spole med trådnet og en spole med nylonline, 15 af hvilke ingen er vist, eftersom deres position ikke er væsentlig. En linefremføringsmekanisme omfattende et antal ruller 4, af hvilke i det mindste nogle er bevægelige i forhold til hinanden for at styre spændingen i linen 3, er anbragt over rørenes påtænkte bane og tilfører line 3 til 20 den side af rørene modsat betonsprøjteindretningen. Stødende op til linefremføringsmekanismen er der en trådfremføringsmekanisme bestående af et par gummibelagte ruller 6 monteret parallelt og drevet modsat roterende af en elektromotor 26 gennem en transmission bestående af drivkæde 27 25 og hjul 28. Rullerne er forsynet med justeringsskruemidler 29 til at bevæge rullerne mod hinanden eller fra hinanden for at justere trykket, der udøves på tråd, der passerer mellem dem, og for tilpasning til forskellig tykkelse tråd. Trådfremføringsmekanismen er beregnet til at give kontinu-30 erlig tilførsel af trådsektioner af en længde passende til at frembringe en vikling omkring rørsektionen, som ligger helt inden i betonbelægningen, der lægges på røret. Til dette formål er der en rulleskæreenhed i trådtilførselsmekanismen direkte i trådens 5 bane, når den kommer ud fra 35 drivrullerne 6. Denne skæreenhed omfatter et par ruller 7, der hver har et skæreblad 8, der strækker sig på langs af DK 172367 B1 7 rullens overflade. Disse ruller er monteret parallelt og er drevet af en elektrisk motor 46 over en kobling 47 og tandhjul 48, så rullerne 7 roterer modsat. Skæreenhedens drivanordning omfatter en kobling 49, der muliggør, at skæreen-5 heden kan frikobles for at tillade fri passage for en læng de tråd mellem rullerne 7.Referring to FIG. 1 and 2, there is now described a wire winding apparatus for use at a station for coating pipe sections 1, which have already received an anti-corrosion coating (such as epoxy resin), with concrete, in which these sections are passed in series past a concrete spray device. (not shown) on a driven roller conveyor shown schematically only by rollers 2. Above this spraying device is arranged a coil with wire mesh and a coil with nylon line, none of which are shown, since their position is not essential. A line feeding mechanism comprising a plurality of rollers 4, at least some of which are movable relative to each other to control the tension of the line 3, is disposed over the intended path of the tubes and supplies lines 3 to 20 to the side of the tubes opposite the concrete spraying device. Adjacent to the line feed mechanism, there is a wire feed mechanism consisting of a pair of rubberized rollers 6 mounted in parallel and driven counter-rotating by an electric motor 26 through a transmission consisting of drive chain 27 25 and wheels 28. The rollers are provided with adjusting screw means 29 to move the rollers toward each other or apart to adjust the pressure exerted on threads passing between them and for adaptation to different thickness threads. The wire feed mechanism is intended to provide continuous feed of wire sections of a length suitable to produce a wrap around the pipe section which lies completely within the concrete coating laid on the pipe. For this purpose, there is a roller cutting unit in the wire feed mechanism directly in the path of the wire 5 as it emerges from the drive rollers 6. This cutting unit comprises a pair of rollers 7, each having a cutting blade 8 extending longitudinally of the roller. surface. These rollers are mounted in parallel and are driven by an electric motor 46 over a clutch 47 and gears 48 so that the rollers 7 rotate opposite. The cutting device drive includes a coupling 49 which allows the cutting unit to be disengaged to allow free passage of a long dew between the rollers 7.

Denne udformning omfatter også i trådfremføringsmekanismen en trådformerenhed bestående af et antal ruller 9, 10, 11, 10 12, af hvilket to 10, 11 er monteret som par parallelt og drevet af en elektrisk motor 36 ved hjælp af kæde 37 og hjul 38 modsat hinanden for at medføre fremføring af tråden mellem dem. De andre to ruller 9, 12 er frit rullende på lejer 54, monteret således for at udgøre uafhængigt juster-15 bare midler til at påføre tryk på tråden, når den føres gennem rullerne 10, 11, hvorved den kan formes i en kurve, som letter påviklingen omkring røret 1.This embodiment also includes in the wire feed mechanism a wire forming unit consisting of a plurality of rollers 9, 10, 11, 10 12, of which two 10, 11 are mounted as pairs in parallel and driven by an electric motor 36 by means of chain 37 and wheels 38 opposite each other to cause the thread to pass between them. The other two rollers 9, 12 are freely rolling on bearings 54, mounted so as to constitute independently adjustable means for applying pressure to the wire as it passes through rollers 10, 11, thereby forming it in a curve which facilitates the winding around the tube 1.

Ved brug af apparatet til udførelse af fremgangsmåden iføl-20 ge opfindelsen trækkes linen 3 til igangsætning af forløbet i en serpentinebane gennem rullerne 4 og føres omkring den forreste ende af det første rør 1 i serien, som, fordi den roterer, vikler linen 3 omkring denne ende i et antal vindinger, som har vist sig tilstrækkeligt til at fastgøre den 25 til rørenden. Derefter behøver den ikke at røres, og den vil fortsætte med at blive trukket gennem fremføringsmekanismen på en uafbrudt, kontinuerlig måde, så længe der er line på spolen, og vil således kontinuerligt blive viklet omkring alle rør, der fremføres i serier gennem belægnings-30 stationen. På en forudbestemt tid, efter at linen er ført gennem apparatet til røret 1, startes trådnetfremføringen, hvorpå tråden skrider frem i kontakt med linen og således styres på rørsektionen. På dette tidspunkt aktiveres også betonsprøjteindretningen, så et betonlag begynder at blive 35 opbygget på det roterende rør, før tråden kommer i kontakt med det. Derefter fremføres line og tråd sammen, så at li- DK 172367 B1 8 nen ligger over den viklede tråd, indtil betonbelægningen er lagt på. I et forudbestemt øjeblik før fuldstændig belægning af røret aktiveres skæreenheden til at overskære tråden, og drivrullerne 6 standses momentant for at frem-5 bringe et mellemrum mellem enden af en trådvikling og be gyndelsen af den næste. På denne måde vikles tråden fuldstændigt indenfor betonbelægningens længde uden at komme i direkte kontakt med antikorrosionsbelægningen på røret. Fordi linen ikke overskæres, vikles den på flere omdrejnin-10 ger efter, at den afskårne ende af tråden er viklet på røret for at frembringe et middel, som har vist sig tilstrækkeligt til at imødegå en "urfjeder-virkning" i tråden inden i den stadig hærdende betonbelægning. Denne line overrives let ved virkningen af den accelererede fremføring af det 15 belagte rør bort fra stationen på en måde, der er kendt inden for fagområdet.Using the apparatus for carrying out the method of the invention, the line 3 for initiating the course of a serpentine web is drawn through the rollers 4 and passed around the front end of the first tube 1 of the series which, as it rotates, wraps the line 3 this end in a number of turns which have proved sufficient to secure it 25 to the pipe end. Thereafter, it does not need to be stirred, and it will continue to be pulled through the feed mechanism in an uninterrupted, continuous manner as long as there is line on the coil, and thus will be continuously wound around all tubes fed in series through coating 30. station. At a predetermined time, after the line is passed through the apparatus to the tube 1, the wire mesh feed is started, whereupon the thread progresses in contact with the line and thus is guided on the tube section. At this point, the concrete spraying device is also activated, so that a concrete layer begins to be built up on the rotating pipe before the wire comes into contact with it. Line and wire are then fed together so that the coating lies over the wound wire until the concrete coating is applied. At a predetermined moment before complete coating of the tube, the cutting unit is activated to cut the thread, and the drive rollers 6 are momentarily stopped to provide a space between the end of one wire winding and the beginning of the next. In this way, the wire is completely wound within the length of the concrete coating without coming into direct contact with the anti-corrosion coating on the pipe. Because the line is not cut, it is wound on several turns after the cut end of the wire is wound on the tube to produce a means which has been found sufficient to counteract a "clock spring effect" within the wire within it. still curing concrete paving. This line is easily overstated by the effect of the accelerated feeding of the coated tube away from the station in a manner known in the art.

Claims

A method for coating pipes with concrete, which comprises passing a series of pipe sections (1) through a concrete paving station, rotating a pipe section (1) about its longitudinal axis in the station, winding thread (5) around the section (1) and applying concrete on the outside of the pipe section (1) during its rotation, characterized in that a line (3) is fed to the rotating pipe (1) before the application of concrete 10 to form a fixed winding of line (3) around the pipe (1). forward end, then advancing a thread (5) together with the line (3) continuously to the rotating tube (1) to form a thread winding (5) overlaid by a winding of line (3) on the tube (1) below laying concrete on the rotating pipe (1) and cutting the wire (5) at a predetermined time before finishing and during the application of the concrete coating, while the pipe (1) is still rotating, thereby embedding the wire (5) into the concrete coating and continuing with advancing line (3) to d a rotary tube (1) after cutting the thread (5) so that the line (3) is wound around the rear end of the tube (1).

Method according to claim 1, characterized in that the thread (5) is formed in a curve before the winding on the tube 25 (1).

Method according to claim 1, characterized in that the line (3) is made of a synthetic fiber material or thin thread. 30

An apparatus for coating pipes with concrete, comprising means for conveying a series of pipe sections (1) through a concrete coating station, means for rotating the pipe section (1) about its longitudinal axis in the station, means for feeding wire (5). ) to the section (1) and means for applying concrete to the exterior of the pipe section (1) during its rotation, characterized in that a line feeding mechanism for continuous feeding of a line (3) to the rotating pipe (1) is disposed close to a wire feed mechanism (6-12) for continuous feeding of a wire length (5) to 5 a rotating pipe section (1) below the concrete coating, said wire feed mechanism (6-12) comprising a cutting unit (7, 8) for limiting the length of thread (5) to be wound around the tube section (1) during its coating. 10

Apparatus according to claim 4, characterized in that the thread feeding mechanism (6-12) further comprises a thread forming unit (11-12) for preforming the thread (5) into a curved shape to facilitate winding on a pipe section (1).

Apparatus according to claim 5, characterized in that the thread forming mechanism (11-12) consists of a plurality of rollers (11, 12), of which at least one roll (11) forms a reaction surface over which the thread (5) is passed. and against which (11) the thread (5) can be formed by exerting pressure on at least one other roller (12) under which the thread (5) is guided.

Apparatus according to claim 4, characterized in that the cutting unit consists of a pair of rollers (7), each having a cutting blade (8) extending longitudinally of the surface of the roll (7) and mounted parallel and driven. of an electric motor (46) over a transmission system (47, 48) which rotates the rollers (7) in the opposite direction and can interrupt the cutting operation to allow thread (5) to pass through.

Apparatus according to claim 4, characterized in that the line feeding mechanism consists of a plurality of rollers (4) mounted in series, through which the line (3) is guided in a serpentine-like manner, of which rollers (4) can be moved relative to one another. to the others to enable the voltage applied to the line (3) to change to DK 172367 B1 11.

Apparatus according to Claim 4, characterized in that the wire feed mechanism (6-12) consists of a pair of rubber-coated rollers (6) mounted in parallel and driven in a counter-rotating manner by an electric motor (26) over a mechanical transmission (27, 28) for passing thread (5) through the mechanism (6-12), these rollers (6) having a screw adjustment mechanism for moving the rollers towards each other or 10 from each other; a roller cutting unit (7, 8) arranged directly in the path of the wire (5) as it emerges from the driven rubber rollers (6) and having a pair of rollers (7) each having a cutting blade (8) extending along the surface of the cutting roller (7), these cutting rollers (7) being mounted in parallel 15 and driven by an electric motor (46) through a mechanical transmission (47, 48) providing opposite rotation of the cutting rollers (7), which transmission (47, 48) comprises a coupling (47) which enables the cutting mechanism (7, 8) to be disengaged to allow free passage of a length of thread (5) 20 between the cutting rollers (7); a filament assembly consisting of a plurality of rollers (6-12), a pair (6) mounted in parallel and driven by an electric motor (26) through a mechanical transmission (27, 28) opposite each other to effect threading (5) between and other rollers (11, 12) mounted such that they constitute independently adjustable means for applying pressure to the thread (5) as it is passed through this pair of rollers (11, 12) whereby it can be formed in a curve which facilitates the winding of a pipe section (1).