DE102011012198A1 - Method for welding plastic pipe at e.g. pipe branches in mine operations, involves welding pipe pieces over pipe connection piece, and canceling clamping process according to cooling of weld zone at pipe pieces and pipe connection piece - Google Patents

Abstract

The method involves displacing a pipe connection piece (2) in a rotating movement. Boundary regions of contours are heated at face surfaces up to plasticization of the boundary regions. The plasticization of the boundary regions is optimized by controlling and regulating rotational speed, contact pressure and temperature. Pipe pieces (3) actuated with one another are welded over the pipe connection piece by quick stop of rotation of the pipe connection piece. A clamping process is canceled according to cooling of a weld zone at the pipe pieces and the pipe connection piece. An independent claim is also included for a device for welding plastic pipes of equal diameter.

Description

The invention relates to a method and apparatus for welding plastic pipes of the same diameter, which are frictionally connected to each other via a rotatable pipe connector by friction welding.

It is known that the connection, in particular of plastic pipes made of the material HDPE takes place either with the mirror welding or the Heizwendelschweißmuffentechnik. In the mirror welding technique, a trench welding machine is used, which must be positioned in the trench and which requires a considerable trench depth and width. The welding process requires a time of at least 30 to 80 minutes depending on the respective nominal pipe diameter, whereby the pipes must not be moved during this time. Due to the long time required for the respective welding process, high costs are incurred due to considerable energy consumption, because of the device blocking an almost total standstill of the laying work, non-utilization of the workforce and thus high time and labor costs. Another undesirable disadvantage of this method is the formation of beads on the inner and outer surfaces of the welds, which may have a height of up to 1 cm. On the inner walls of the pipe, the bead is a flow obstacle for the future medium and in the inliner is also the outer bead a disadvantageous phenomenon, because the beading outside the insertion of the tubes severely hindered and the beads inside must be removed by additional operations with sophisticated robotics. Because of this high labor time and material costs, the actually high-quality HDPE pipe in sewer pipe construction has not yet prevailed. The, for an economic application, necessary longer pipe shots are not applicable because of the usual in the civil engineering Rohrtaktlängen 3-6 m. A further disadvantage is that the trench installation lengths are very short and crossing lines and cables often make the use of larger pipe lengths impossible.

When Heizwendelmuffenschweißverfahren fall to the, approximately similar wage u. Equipment costs such as in mirror welding, also considerable material costs for the purchase of prefabricated Heizwendelmuffen. Therefore, the cost of both of the above methods is about the same. The choice of the connection technology depends essentially on the site conditions and the specification by the client. While the use of the electrofusion method does not produce an internal weld bead, the processing times are somewhat shorter and a cheaper, handy welding machine with less energy consumption can be used. However, the method results in a disadvantageous lower welding factor and in inliner construction it requires, because of the very high-order raised Heizwendelmuffe, a higher space requirement, which is why the method for inliner technology is not usable.

From the DE 37 08 705 A1 a method and apparatus for welding tubular plastic parts is known which is intended to avoid the formation of beads on the welds. The object is achieved in that the parts to be connected aligned, after impact of heat abutting each other and are welded together at the abutting surfaces. For this purpose, the abutting surfaces of the pipe ends to be joined in the direction of the pipe interior are undercut or beveled such that the edge formed by the inner surface of the pipe ends and the abutting surface to be recessed relative to the edge formed by the outer surface of the parts and the abutment surface, the parts to be joined softened equally deep in the axial direction, then pushed and thereby welded together. The joint is contacted with a heating element provided with abutment surfaces corresponding to the undercut or fluted joints of the pipe ends. The softened abutment surfaces are pushed together. The heating element is preferably designed as an electrical resistance heater and at the same time allows centering and calibrating the pipe ends. The method and apparatus is not automatically practicable, the construction and procedures are time consuming and costly and complicated and prone to rough handling in trenches on-site in terms of handling requirements.

In the DE 24 08 120 C3 Also disclosed is an apparatus for joining two tubular members by friction welding. Their object is a device with a frame on which a rotatably driven, central chuck, which carries an intermediate piece between the surfaces to be joined of the tubular elements and outer chuck for holding the tubular elements and axial force thrust cylinder, with which the tubular elements with adjustable contact pressure can be brought into contact with the intermediate piece. The object is achieved by a device in which a Axialschubkraftzylinder between the two tubular elements and another Axialkraftschubzylinder between the frame and the central chuck works, characterized in that the rotatably driven central chuck and the outer chuck are each designed as a total of two-piece assembly whose parts are hinged about an axis parallel to the axis of the chuck. The tensioning organs of the central chuck have drives that work together with centering devices. The clamping members of the central chuck and the outer chuck are designed as self-tightening and self-centering cam grippers. For deburring the welded joints of the tubular elements, one or more, along the axis of the tubular elements, movable tools are provided which have a cutter, a rotary brush and reamers. In a further variant, the central chuck and its actuators and the outer chucks are arranged inside the tubular elements and the intermediate piece and the central chuck deburring tools and a set with a metal brush and Spanabstreifscheiben are provided to deburr the welds outside. For internal deburring a complex robotics is required. The process is a pure and very center-consuming butt welding technique with a complex post-processing.

This device is a complex and complicated construction. It requires large excavation depths because the fixture frame must be installed in the laying trench and stiffened and stabilized with support columns and struts for the apparatus to operate. Another major disadvantage is that the parts to be joined are welded in the warmed-up state to shock with high contact pressure, whereby Schweißwulste arise that must be removed by various, structurally complex Entgratungsvorrichtungen.

Also the DE 21 27 663 B2 , discloses a friction welding method in which a, between the faces of two elements to be welded metal or thermoplastic material, axially movable arranged intermediate piece is rotated while the elements are pressed against the intermediate piece, characterized in that directly on the intermediate piece an additional, due comparative measurements at the two welds controlled axial force is applied.

The additional axial force is controlled by temperature measurements at the joints in the plasticized state of the boundary areas during the welding process, gradually approached by the pipe section and spacer in the heated state and depending on the different temperature conditions at the seams gradually different and pressed and then cool, before the device can be removed. In a preferred embodiment of the method, the intermediate piece is first brought to its normal rotational speed and only then are the elements to be joined brought together with the intermediate piece. The additional axial pressure according to the invention must be maintained until the welds have cooled.

The device for carrying out the method is permanently installed on a frame and is transported below the pipes to be connected movably in a trench. The assembly of the device requires several workers and a considerable installation effort.

Finally she sees DE 10 2006 026 275 A1 a device for deforming, positioning and processing of pipelines for integration into an underground or water-laid pipeline transport system with at least one clamp, each consisting of several coupled peripheral sections, wherein the peripheral sections for fully encompassing a pipeline are mutually movable. The peripheral sections or their respective two clamps must be closed with a bolt below the pipeline. Laterally, the clamps are coupled according to claim 9, with at least one tool carrier. According to claim 12, the device provides that a welding device and / or a cutting tool, a sawing tool, a chamfering tool, a testing device or a Nachumhüllungsvorrichtung is coupled to at least one tool carrier. The tool carrier requires the circular rotation of the tool around the respective pipe ends or around an intermediate piece and the two pipe ends adjacent thereto. A friction welding is not feasible with this device, since the tools must be rotated around the tubes and the intermediate piece. In claim 13 it is provided that the device is held on a mounting frame which is mounted on a vehicle. Although this device allows the deformation, positioning and processing of pipelines, a friction welding would be with the arrangement of one or more tool carrier assembly and time-consuming. The fully encompassing clamping means increase the considerable installation effort with several workers.

It was therefore an object of the invention, a method and an apparatus for welding plastic pipes of the same diameter, so educate, that they provide a Reibschweißverbindung with individually producible on the site, pipe lengths, pipe spacers, pipe branches and pipe bends, in which no Schweißwulste arise and in the the tubes are flush with the wall both inside and outside, that they allow short processing times and largely automated protocolable workflows without disability or work stoppage, saving wages, equipment, materials and energy and that they are an optimal effort for the excavation of a Laying trench or for a ground-level installation, increase the propulsive power and can be used both in pipeline construction, in pipelines and general civil engineering, as well as in workshop and plant construction.

The object is achieved by a method having the features of claim 1.

To emphasize is the inventive method in which an already buried and / or ground-mounted first pipe section, a pipe connector with assembled in opposite faces contours and a second cut pipe section independently in a horizontal axis to grab and held in the end faces of the two axially held pipe sections on both sides and at the same time a contour is to be milled, which form the counterpart to the in the end faces of the pipe connector, prefabricated contours, in order in the axial direction of the first contoured end face of the pipe connector to the, with the counterpart milled contour provided end face of the first pipe section and the opposite, assembled with the contour end face of the pipe connection piece the end face with, milled as a counterpart contour of the second pipe section in axial direction in alignment with each other to be connected by the interlocking contours self-centering and at the same time ovalisierungsgleichgleichend mechanically firmly, and to put the pipe connector in rotary motion, the mechanically merged boundary regions of the contours on the faces to heat plasticizing, by control and regulation the rotational speed, the contact pressure and the temperature to optimize the plasticization is to be welded together by a quick stop of the rotation of the pipe sections via the pipe connector and the gripping operation on the pipe sections and the pipe connector after cooling the weld zones is to lift.

Of particular importance is the milling of the different contours, according to claim 2. The contours and contours, depending on the material thickness, the material and the intended use, in an acute angle at a 45 ° angle centric and eccentric, at different acute angles to the pipe sections and the Pipe coupling centric and eccentric, with and without Schweißgut-Vorratsfase on the outer edges of the pipe sections, centric frusto-conical and mirror-image, centric and eccentric wavy with and without Schweißgut-Vorratsfase on the pipe sections and circular segment with symmetrical and asymmetric radius and with and without weld metal Vorratsfase on the end faces of the pipe ends and the pipe connector are to be used when merging the pipe sections with the pipe connector of the mechanical centering and ovalization compensation of the pipe ends before the welding process. Moreover, in the welding operation with the various shapes of contours on the end faces, the heat generation and the centrifugal expulsion of the plasticized material components in the boundary regions of the parts to be joined is better controlled. For example, with an eccentric acute-angled contour, heat is generated first in the eccentric tip and then continuously outward and inward, and the plasticized material is propelled outward by the centrifugal force over the longer path. By the contours resulting larger run lengths, which lead to an enlargement of the weld contact surface and the friction surface. In this way, the material is not pushed beyond the tube outer circumference and inner circumference and no weld bead is produced. Also, at the outer edges of the pipe sections milled weld stock chamfers can absorb the expelled plasticized material and thus prevent the formation of weld beads.

Each of the selected contours has a shape characteristic which ensures mechanical self-centering and ovalization compensation at the tube ends prior to the welding operation and the prevention of internal and external weld beads during the friction welding process. Subsequent and expensive milling work to eliminate annoying inner and outer beads on the welds omitted, the device structure simplifies. The mechanical interlocking of the contours saves complex centering devices, which make the device structurally complicated and require a higher material, time and cost.

Particularly noteworthy is the apparatus for performing the method according to claim 4, which is equipped as an attachment for mobile and / or stationary machines with lifting function and with Eletro- and hydraulic connection, has a corresponding connector, which have three gripping devices, each with two partially gripping jaws and which is fully automatic, SPC controlled and therefore to be used inside and outside a trench. The device can thus be lowered within or outside a laying trench to the workplace and automatically reach and hold the aligned pipe sections and therebetween a pipe connector with prefabricated contours on the end faces, by means of a plurality of independently operable gripping devices.

Particularly advantageous is the gripping device for the pipe connector, which is equipped with a, on both sides and peripherally, independently of the gripping means of the pipe sections, vertically raised and lowered in the work area, milling device. This is to move out of the work area after completion of the milling work, without having to solve the gripping means of the pipe sections and the pipe connector. The milling process is arbitrary to repeat.

In accordance with claim 5, a variety of contours can be attached to the end faces of the pipe sections to be connected on site and with a, arranged on the milling device, separate drive, the rotation of the pipe connector with the ready-made end faces generated and regulated and between two pipe sections and the pipe connector friction welding be performed.

The lifting function as well as the power and hydraulic supply of a mobile or stationary machine, for example an excavator, are thus usable for the control of the device in which they can be easily coupled with the mobile or stationary machine and fully automatic, SPC-controlled inside or outside a laying trench is to be operated. This has the advantage that the device, which consists essentially of an assembly, does not have to be self-erected and anchored, no additional labor to attach the device to the pipe sections and the pipe connector are required and no additional energy and hydraulic sources are needed.

The connectors can be assembled prior to installation and cut the pipe sections according to required installation lengths, channel holding lengths and hindering line crossings regardless of delivery lengths on site and their faces are processed on site with the milling device according to the invention.

After the welding operation, the device can be lifted out of the laying trench or away from the ground-level working place, the workers can carry out the next excavation or laying cycle without lengthy work obstruction or even standstill, carry out the positioning of the next pipe joint and the next pipe section and perform the welding process repeat described. There are considerable time savings and shortening of tunneling times.

The basic structural design of the device according to claim 6 and 7, is particularly simple, to the effect that at least four orthogonally along a longitudinal edge adherent arranged parallel spaced bearing elements and at the opposite longitudinal edge at least four parallel spaced bearing elements are arranged on the connecting part, in whose free ends each a continuous support shaft is mounted. In this case, a cylinder for axial movement of the gripping means is arranged on the support shaft between the two parallel Teilumgreifenden jaws of the gripping devices for the pipe sections and the terminal device has between the first support shaft and the second support shaft at the bearing points of the parallel teilumgreifenden clamping jaws, transverse to the advancing direction, respectively a clamping cylinder for opening and closing the gripping means.

It should also be emphasized that essentially only one central support shaft is required to accommodate all the essential parts of the device, via which the axial displacement of the gripping devices, de independent gripping functions, the rotational movement for the friction welding and the operation of the milling on both sides of the gripping device for the pipe connector, are feasible. This allows a structurally simple, easy-to-use and cost-effective device.

Of course, the method and the device both in piping and general civil engineering, as well as in pipeline construction and workshop and plant construction can be used.

The invention is described below with reference to an embodiment. The drawings show in

1 Side view of a laying trench,

2 the front view of the attachment,

3 the side view of 2 .

4 a sectional view through a junction of a Reibschweißverbindung between two pipe sections via a pipe connector.

5 the presentation of a selection of side views of possible contour shapes,
the same parts are marked with the same numbers.

1 shows the side view of a basic representation of the process sequence according to the invention in a laying trench. In the laying trench is a piece of pipe 3 already laid and buried, in the distance is a pipe connector in the axial direction 2 and then a new piece of pipe to be laid 3 to recognize. In the advancing direction is outside the trench, on the not yet excavated soil, such as a conventional excavator on which a device according to the invention 1 , in the form of an attachment, coupled and lowered into the laying trench. The device 1 is connected to the energy and hydraulic supply of the excavator and fully automatic with SPC control by means of a gripping device 5 the already buried pipe section 3 with a middle gripping device 4 the pipe connector 2 and with the third gripping device 5 the new piece of pipe to be laid 3 independently of each other. The pipe connector 2 is on both ends 2.1 preferably with a contour, according to 4 , made to fit into the ditch before insertion. The middle gripping device 4 is with a, not shown in the drawings, on both sides and circumferentially, can be raised and lowered in the radial direction milling device 4.1 and a drive 4.2 fitted. The milling device 4.1 is now working at the front ends 3.1 the two pipe sections 3 lowered and milled the mating contours to those of the pipe connector 2 in the frontal areas 3.1 the pipe pieces 3 one. Then the milling device 4.1 back out of the work area without the gripping devices 4 and 5 to have to solve. Now you can with the help of an axially movable cylinder 6 that between the clamps 5.1 the gripping device 5 is arranged, the end face 3.1 of the newly laid pipe section 3 to one of the faces 2.1 of the pipe connector 2 and the second end face 2.1 of the pipe connector 2 to the face 3.1 of the already buried pipe section 3 be merged in the axial direction. The prefabricated contours of the pipe connector grip 2 on both sides in the fresh milled counter contours of the pipe sections 3 initially mechanically, the pipe sections 3 and the pipe connector 2 are centered in alignment, engage in each other in an ovalization-compensating manner and are held together mechanically with a controlled contact pressure. Now with the help of the drive 4.2 the gripping device 4 the pipe connector 2 set in rotation, with the boundary areas of the faces 2.1 and 3.1 uniformly heated on both sides, plasticized and non-positively welded together by friction welding. After a short cooling time, the welded composite has cooled and stabilized so far that the device 1 can be detached from the pipe assembly with the help of the excavator and lifted out of the laying trench. The workers can make the new excavation stroke in the direction of advance, a new pre-assembled pipe connector 2 and another piece of pipe 3 in the laying trench and the welding process can be repeated as described. Of course, this procedure is also applicable at ground level, for example when laying a pipeline or in stationary workshop and plant construction.

2 and 3 show the principal front and side view of the device according to the invention 1 as an attachment, for example, for an excavator. The device 1 has a connection part 1.1 with along its one longitudinal edge, for example, four rectangular and parallel spaced, non-positively arranged bearing elements 1.2 and along its opposite longitudinal edge four parallel spaced bearing elements 1.3 on. In the free ends of the bearing elements 1.2 is a holding wave 1.4 and in the ends of the bearing elements 1.3 a support shaft 1.5 stored in a conventional manner. On the support shaft 1.4 are preferably a gripping device in the order 5 with two jaws 5.1 , a gripping device 4 preferably with two jaws 4.3 and a second gripping device 5 with two jaws 5.1 and between the jaws 5.1 for example, in each case an axially movable cylinder 6 stored. Between the two support shafts 1.4 is at the bearings of the jaws 5.1 and opposite to the support shaft 1.5 transverse to the direction of advance in each case a clamping cylinder 7 arranged, which is the gripping function of the jaws 5.1 the gripping devices 5 guaranteed. At the gripping device 4 is a, not shown in the drawings, on both sides and peripherally, radially raised and lowered, milling device 4.1 arranged, with the help of which the end faces 3.1 the two, to be welded together pipe sections 3 be provided with a counter contour and a pipe connector 2 with end faces 2.1 can be welded with prefabricated contours. In addition, the gripping device has 4 via a drive 4.2 with which the rotation of the pipe connector 2 to perform and regulate for the friction welding process.

In 4 the section is represented by a welded joint with a preferred contour. However, there are other contour features, such as in 5 shown applicable.

LIST OF REFERENCE NUMBERS

1

Device in the form of an attachment,

1.1

Connector,

1.2

Bearing elements,

1.3

Bearing elements,

1.4

Holding shaft,

1.5

Holding shaft,

2

prefabricated pipe connector,

2.1

Faces,

3

Pipe section,

4

middle gripping device,

4.1

milling device,

4.2

Drive,

4.3

Jaws

5

right and left gripping device,

5.1

Jaws

5.2

annular pressure surfaces,

6

axially displaceable cylinders,

7

clamp cylinders

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3708705 A1 [0004]
• DE 2408120 C3 [0005]
• DE 2127663 B2 [0007]
• DE 102006026275 A1 [0010]

Claims (7)

Method for welding plastic pipes of the same diameter, in which a rotatable pipe connector ( 2 ) by friction welding two pieces of pipe ( 3 ) are positively connected to each other, characterized in that an already buried and / or ground-mounted first tube piece ( 3 ), a pipe connector ( 2 ) with, in opposite end faces ( 2.1 ) prefabricated contours and a second cut piece of pipe ( 3 ) are independent of each other in a horizontal axis to grip and hold that in the end faces ( 3.1 ) of the two axially held pipe pieces ( 3 ) on both sides and at the same time a contour is milled, which is the counterpart to the in the end surfaces ( 2.1 ) of the pipe connector ( 2 ), prefabricated contours form, that in the order in the axial direction, the first contoured with the contour face ( 2.1 ) of the pipe connector ( 2 ) to the, provided with the counter-milled contour contour face ( 3.1 ) of the first pipe section ( 3 ) and the opposite, with the contour, prefabricated end face ( 2.1 ) of the pipe connector ( 2 ) the end face ( 3.1 ) with the counter-milled contour of the second pipe section ( 3 ) in the axial direction to each other in alignment, by the interlocking contours self-centering and at the same time ovalization compensating mechanically firmly connected and that the pipe connector ( 2 ) to set in rotation, the mechanically merged boundary regions of the contours on the end faces ( 2.1 and 3.1 ) to heat to plastification and to optimize by controlling the speed of rotation, the contact pressure and the temperature of the plasticization, whereby by a quick stop the rotation of the pipe connector ( 2 ) the pipe pieces ( 3 ) via the pipe connector ( 2 ) are non-positively welded together and the clamping operation after cooling of the weld zone on the pipe sections ( 3 ) and the pipe connector ( 2 ) is to be lifted. Method for welding plastic pipes of the same diameter, according to claim 1, characterized in that the end faces ( 2.1 and 3.1 ) are to be provided with contours depending on the thickness of the material, the material and the intended use, which at a 45 ° angle at an acute angle centric and eccentric, at different acute angles to the pipe sections ( 3 ) and the pipe connector ( 2 ) centric and eccentric, with and without weld material Vorratsfase on the outer edges of the pipe sections ( 3 ), centrically frustoconical and mirror-inverted, centric and eccentric undulating with and without Schweißgut-Vorratsfase on the pipe sections ( 3 ) as well as circular segment with symmetrical and asymmetrical radius and with and without weld material Vorratsfase are to be executed, which is to produce a uniform axial and radial heating and plasticization of the boundary regions and a bead-free weld in a short time. Method for welding plastic pipes of the same diameter, according to claim 1, characterized in that instead of the pipe connector ( 2 ) a branch pipe branch is used. Contraption ( 1 ) for carrying out the method according to claim 1, comprising a plurality of gripping devices ( 4 and 5 ) with two parallel jaws ( 4.3 and 5.1 ), a plurality of cylinders to be displaced in the axial direction ( 6 ) and several clamping cylinders ( 7 ), characterized in that the device ( 1 ) is designed as an attachment for mobile and / or stationary machines with lifting function and with eletro- and hydraulic connection, via a connecting part ( 1.1 ), the three gripping devices ( 4 and 5 ) in each case two teilumgreifende jaws ( 4.3 and 5.1 ) and the device ( 1 ) is fully automatic, SPC-controlled and is to be used inside and outside a laying trench and that the gripping device ( 4 ) of the device ( 1 ) with a double-sided, independent of the gripping devices ( 4 and 5 ), vertically in the work area raised and lowered milling device ( 4.1 ), the milling device ( 4.1 ) is to be moved out of the working area after completion of the milling operations, without the gripping devices ( 4 and 5 ) and that the process must be repeated. Device for carrying out the method according to claim 4, characterized in that with the milling device ( 4.1 ) various contours on end faces ( 3.1 ) to be connected pipe pieces ( 3 ) and with one, at the milling device ( 4.1 ), separate drive ( 4.2 ) the rotation of the pipe connector ( 2 ) with the prefabricated end faces ( 2.1 ) and between two pipe sections ( 3 ) a friction welding is to be performed. Device for carrying out the method according to one of the preceding claims, characterized in that the connecting part ( 1.1 ) at least four perpendicularly along a longitudinal edge frictionally arranged parallel spaced bearing elements ( 1.2 ) and at the opposite longitudinal edge at least four mutually parallel spaced bearing elements ( 1.3 ), in whose free ends in each case a continuous support shaft ( 1.4 ) and ( 1.5 ) is stored. Device for carrying out the method according to one of the preceding claims, characterized in that on the support shaft ( 1.4 ) between the two parallel Teilumgreifenden clamping jaws ( 5.1 ) of the gripping devices ( 5 ) a cylinder ( 6 ) for the axial movement of the gripping devices ( 5 ) and for generating the contact pressure is arranged and the terminal device ( 1.1 ) between the support shaft ( 1.4 ) and the support shaft ( 1.5 ) at the bearing points of the parallel partially gripping jaws ( 5.1 ), transversely to the direction of advance, in each case one of the clamping cylinders ( 7 ) for opening and closing the gripping devices ( 5 ) having.

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