DE4432199A1 - Welding of plastic socket onto plastic pipe - Google Patents

Abstract

In a process for connecting a plastic socket (12) onto a plastic pipe (11), both pieces (11,12) are mfd. separately and the opposing faces of both pipe (11) and socket (12) correspond to each other. An electrically heated welding mat (1) is introduced between the faces to be welded and when current is applied to the mat (1) the opposing faces of the components (11,12) are pressed together.

Description

The invention relates to a method for connecting a plastic tube with a plastic sleeve according to the preamble of claim 1.

For the production of pipe connections it is generally advisable that the pipe sections are provided with a sleeve that is fixed to the Pipe is connected, because on the one hand sealing rings and on the other Raw materials can be saved. This is particularly the case with sewer pipes important, where relatively short pipe sections are used will.

Simple pipes, i.e. H. Solid wall pipes, which are not composite pipes, can be made of PVC. Such pipes can be retrofitted be called up, d. H. the end portion of a pipe is heated and then expanded on a mandrel. This method is from EP 0 271 598 A2 also known for composite pipes, that is, a smooth inner pipe and have a corrugated outer tube. Problems arise to this extent than the risk of damage to the corrugated outer tube when the connection is made fen, i.e. when expanding. This is very time consuming slow warm-up process ahead. If the polyolefin pipes, for example, polyethylene, then the subsequent up do not have to because of the so-called memory effect of these plastics or only possible to a very limited extent. If such pipe sleeves subsequently that are heated, they return to their original geometry. The sleeves are therefore not dimensionally stable.  

It is known from EP 0 231 446 B1 (corresponding to US Pat. No. 4,779,651) that to manufacture a sleeve on a composite pipe online on the molding machine len. Since polyolefins require a high cooling capacity, this is the pro production speed on the molding machine is relatively low, what this Type of forming a sleeve on a composite pipe makes it uneconomical.

From US-PS 3 897 090 it is known to have a sleeve on the molding machine molded onto a simple corrugated pipe.

To the problems that arise when connecting composite pipes avoid, it is known from EP 0 271 598 A2, at the end of a Injection molding a sleeve. This leads to satisfactory Results, however, is complex, since the pipe also corresponds to one appropriate injection mold must be included. The Apparative Auf So wall is significant.

The invention has for its object a method of genus moderate way so that a plastic sleeve in a simple manner is reliably connected to a plastic pipe, and also, if both are made of polyolefin.

This object is achieved by the features in the characterizing part solved part of claim 1. By the measure according to the invention all types of pipes can be used and without separate ap parative effort can be provided with a sleeve. The procedure can on solid wall pipes or according to claim 3 on corrugated pipes or after Claim 4 can be applied to composite pipes. The sleeve can go through Injection molding or extrusion. When the sleeve through Injection molding is made, then injection molding can already the welding mat can be integrated into the sleeve. The welding mat can therefore already in the injection mold when manufacturing the sleeve be inserted. Welding with a welding mat is possible quickly. Details of this can be found in the subsection sayings 2 to 11. According to claims 12 and 13, the fiction Proper procedures can also be used to make up two identical sleeves  by means of a very short pipe section, a double push-in socket put.

Further features, details and advantages of the invention emerge from the description of exemplary embodiments with reference to the drawing.

It shows

Fig. 1 is a welding mat in top view,

Fig. 2, the welding mat in cross section along the line II-II in Fig. 1,

Fig. 3 shows a sleeve and a composite tube in a preassembled condition prior to welding,

Fig. 4 weld the composite tube and the sleeve of FIG. 3 according to the Ver.

Fig. A welded with a composite pipe sleeve, said Ver composite pipe is provided with an additional cladding tube 5,

Fig. 6 approximately form a composite pipe with a socket in a modified exporting,

Fig. 7 is a composite pipe having a socket with a modified exporting approximate shape of the welded joint in a preassembled condition,

Fig. 8 was the composite tube and the sleeve of FIG. 7 in welded to,

Fig. 9 is a composite pipe with a cylindrical sleeve,

Fig. 10 is a comparison with FIG. 9 added embodiment,

Fig. 11 is an embodiment corresponding to FIG. 9 with a composite pipe with a sheath tube,

Figure 12 is a composite pipe form. With a sleeve in a modified execution,

Fig. 13 is a composite tube with prefabricated sleeve in comparison with FIGS. 3 and 4, a slightly modified embodiment,

Fig. 14 is a sleeve in an embodiment according to FIGS. 3 and 4 mounted in to a solid-wall pipe state,

Figure 15 fen. A composite short-tube portion with two welded MUF

Fig. 16 shows a short massive pipe section with two welded sleeves and

Fig. 17 shows a short section of a composite pipe with two welded sleeves.

Fig. 1 and 2 show a so-called welding mat 1, the metrical from an elec resistance heating wire 2 is provided with a plastic order sheathing, which is identical to the plastic together to ver welded parts or at least ver with these is weldable. This provided with a plastic sheath 3 heating wire 2 is meandering, so that the individual straight sections 4 are parallel to each other and without any gaps. In this way, the welding mat 1 shown in FIGS . 1 and 2 is formed. It can be bent parallel to the longitudinal direction 5 of the sections 4 . It is also bendable about the main longitudinal direction 6 of the welding mat 1 . The two longitudinal directions 5 and 6 lie in the main plane of the welding mat 1 corresponding to the plane of the drawing in FIG. 1 . Finally, the welding mat 1 can also be deformed by an accordion-like pulling apart on the main plane formed by the drawing plane of FIG. 1, this pulling apart taking place about an axis not shown in the drawing and perpendicular to the drawing plane. Here, the Bogenab lying on a longitudinal side sections 7 are in a certain distance from each other placed, while the opposite arc sections 8 to each other remain close together. The straight sections 4 extending in the longitudinal direction 5 are then no longer exactly parallel to one another. The two end sections 4 are bent at the two ends of a welding mat 1 of the length required for an application and then serve as power connections 9 , 10 . Such welding mats 1 are known in principle, for example from EP 0 146 775 B1.

Fig. 3 shows a composite pipe 11 to which a sleeve 12 is to be attached. The composite tube consists of a smooth, that is, cylindrical inner tube 13 and a corrugated outer tube 14 , which is welded to the inner tube 13 at the bottom 15 of its corrugation 16 . The corrugation 16 has flanks 17 , 18 and outer ring webs 19 connecting them. The production of such composite pipes 11 is generally known and is shown and described, for example, in EP 0 065 729 B1 (corresponding to US Pat. No. 4,492,551). The sleeve consists essentially of a cylindrical portion 20 , whose inner diameter d₂₀ is slightly larger than the outer diameter d₁₁ of the composite pipe 11 , so that an identical to the composite pipe 11 composite pipe can be pushed into the sleeve 12 ge. The sleeve 12 also has at one end of the cylindrical portion 20 an inward, that is to say the central longitudinal axis 21 of the composite pipe 11 and the sleeve 12 open annular chamber 22 for receiving me a sealing ring. So that such a seal reliably comes to rest against at least one annular web 19 of the corrugation 16 , the extension a of the annular chamber 22 in the direction of the axis 21 is greater than the outer distance b between two adjacent corrugations 16 or two adjacent annular webs 19 . In practice, sealing will take place against a solid wall tube inserted into the sleeve 12 or a composite tube with a sheathing tube. At the annular chamber 22 is followed by a funnel-shaped insertion opening 23 for a tube with the same Ver 11 tube.

At the end of the sleeve 12 opposite the insertion opening 23 , a welding flange 24 is formed, which has a frustoconical section 27 running parallel to the facing flank 17 of the corrugation 16 and a cylindrical section 26 running parallel to the adjacent section 25 of the base 15 of the corrugation 16 . The welding flange 24 is connected by means of a transition section 28 to the cylindrical section 20 of the sleeve, this transition section 28 connecting to the cylindrical section 26 .

As can be seen in FIG. 3, on the section 25, an approximately L-shaped deformed welding mat 1 is pushed on in the manner described above, which has a cylindrical section 26 resting on section 25 and a frustoconical section 27 resting against the flank 17 . The heating wires 2 run such that an originally straight-line section 4 lies in the plane of the drawing. They therefore run over section 25 and flank 17 and then vice versa. The inner diameter d₂₆ of the cylindrical portion of the welding flange 24 is twice the thickness c of the welding mat 1 larger than the outer diameter d₁₅ of the portion 25 of the bottom 15 of the corrugation 16th The sleeve 12 is made in one piece by injection molding and consists of the same polyolefin as the composite pipe 11 .

As is apparent from Fig. 4, the sleeve 12 and the composite tube to be compressed in the direction of the central longitudinal axis 21 11, so that the weld flange 24 firmly abuts the portions 26 and 27 of the welded mat 1, which in turn firmly against the flank 17 and section 25 are depressed. Current is supplied via the power connections 9 , 10 and the welding mat 1 is thereby heated, so that its plastic sheathing 3 and the adjacent areas of the welding flange 24 and the flank 17 and the section 25 are melted. If sufficient melting has taken place, the current is switched off, so that the molten plastic cools and a permanent weld between the sleeve 12 and the composite pipe 11 is generated.

In the description of all the following exemplary embodiments  identical parts with identical reference numbers and functionally the same, constructively but slightly different parts with identical reference numbers and one or more superscript dashes without it each requires a new description.

As can be seen in FIG. 5, the composite tube 11 'on its outer side can also be provided with an additional sheathing tube 29 to significantly increase the ring rigidity. The welding of the sleeve 12 with the composite pipe 11 'is carried out in the same manner as in the embodiment of FIGS. 3 and 4.

Fig. 6 shows a sleeve 12 ', the cylindrical portion 20 ' is still provided with ribs 30 so that the sleeve 12 'has the same rigidity as the composite pipe 11 . Here, too, the type of welding between the sleeve 12 'and the composite pipe 11 is identical to the exemplary embodiments shown in FIGS . 3 to 5.

FIGS. 7 and 8 show a composite tube 11 which is identical to Figs. 3, 4 and 6. The sleeve 12 '' differs from the one described above in the design of the welding flange 24 ''. The welding flange 24 '' has a cylindrical portion 26 '', the inner diameter d''₂₆ is approximately equal to the outer diameter d₁₅ of the section 25 . The frustoconical section 27 '' runs parallel to the flan ke 17 and has cylindrical outer sections 31 at its outer end. The welding mat 1 is bent approximately in a C-shape and lies on the annular web 19 of the corrugation and at least partially against the flanks 17 , 18 of the corrugation 16 . While Fig. 7 shows a pre-assembled position of the sleeve 12 '' and shows the composite pipe 11, in Fig. 8, the state after the welding of the sleeve 12 '' with the composite tube 11 provides Darge. Also here are during welding, ie when the Stromanschlüs se 9 , 10 are supplied with current, the sleeve 12 '' and the composite pipe 11 in the direction of the axis 21 , and / or radially pressed together to the axis 21 .

Fig. 9 to 11 show the attachment of a sleeve 32 to a composite pipe 11. The sleeve 32 is made of a ring-cylindrical solid wall tube, as is customary for the sleeve area of solid wall tubes. Solid wall tubes of this type are produced by extrusion. The inner cylindrical surface 33 of the sleeve 32 is accommodated in the with the composite tube 11 to connecting portion 32 a by machining on an inner diameter d₃₃, of the outer diameter of the annular webs D₁₁ 19 of the undulation 16, so the composite tube 11, plus c two times the thickness of the Welding mat 1 corresponds. The welding mat 1 is bent into an annular section 34 about the axis 21 and lies firmly on the ring webs 19 of two adjacent corrugations 16 . When the current connections 9 , 10 are supplied with current, the ring webs 19 are welded to the associated section of the inner surface 33 of the sleeve 32 . The area 32 b of the sleeve 32 which is not welded to the composite pipe 11 has an inner diameter which is smaller than the inner diameter d 3 3, so that at the transition from the area 32 b to the area 32 a an annular collar 32 c is formed, which is also more flush Can serve for the annular section 34 of the welding mat 1 , which can be inserted into the area 32 a.

In order to avoid excessive deformation of the composite tube 11 in the region of the ring web 19 forming the wave crest, in the embodiment according to FIG. 10 a divided or slotted ring 35 with a cross section is inserted into the space between the two adjacent corrugations 16 , which roughly corresponds to the base 15 and the two flanks 18 , 17 that border these. This ring 35 lies approximately flush on the outside with the adjacent ring webs 19 .

In the embodiment according to FIG. 11, a composite tube 11 'with a sheathing tube 29 is used, as is also provided in the embodiment according to FIG. 5. In this case, the area 32 'a of the sleeve 32 ' has an inner diameter d'₃₃ of its inner surface 33 ', which corresponds to the outer diameter d'₁₁ of the casing tube 29 plus two times the thickness c of the welding mat 1 . In the embodiments according to FIGS. 9 to 11, the area 32 a or 32 'a is pressed radially from the outside to the axis 21 against the composite pipe 11 or 11 ' during welding.

Fig. 12 shows the connection of a sleeve 12 '''with a composite pipe 11th The cylindrical portion 20 of the sleeve 12 '''is pushed over the ring web 19 of the first corrugation 16 of the composite pipe 11 . At the cylindri's section 20 is also an annular cylindrical welding flange 24 ''', the inner surface 33 merges with an annular collar 33 a in section 20 . The formed as an annular portion 34 welding mat 1 is in the welding flange 24 '''against the collar 33 a and is flush with the cylindrical portion 20th You can in the manufacture of the sleeve 12 '''by injection molding firmly with the sleeve 12 ''' a related party by inserting it into the injection mold before injection molding. Here, too, the welding flange 24 '''is pressed radially to the axis 21 against the composite pipe 11 during welding.

FIG. 13 shows an embodiment which corresponds to FIGS. 3 and 4, only the welding mat 1 being already firmly connected to the welding flange 24 of the sleeve 12 . For this purpose, it has been inserted into the injection mold in a preformed form.

Fig. 14 shows an embodiment with a sleeve 12 '', as shown in FIGS. 7 and 8. In this case, a solid wall tube 41 is connected to the sleeve 12 '', the end face 42 of the course of the welding flange 24 '' of the sleeve 12 '' is adapted.

In the embodiment of FIG. 15 are two identical couplers 12 which are arranged mirror-symmetrically to one another, connected to a segment 36 of a composite pipe 11. This segment 36 has a wel development 16 and the associated area of the inner tube 13 . The connection of the mirror-symmetrically arranged sleeves 12 with this segment 36 is carried out as in the exemplary embodiment according to FIGS. 3 and 4. The welding flange 24 of the sleeve 12 shown on the left in the drawing is cut by means of the welding mat 1 with the flank 17 and from 25 of the base 15 is welded, while the welding flange 24 of the other sleeve 12 is welded to the flank 18 of the corrugation 16 and a section 37 of the base 15 . In this way, a double push-in socket is produced.

In the embodiment of FIG. 16 again two mirror-symmetrically arranged sleeves 12 are welded ver with a circular ring 38 , which has an inner pipe section 39 and an outer pipe section 40 with flanks 17 ', 18 '. In the area in which the welding mats 1 abut with their respective cylindrical section and their respective frustoconical section against the pipe sections 39 , 40 , these have dimensions as described above for the exemplary embodiment according to FIGS. 3 and 4. The outer Rohrab section 40 comes to the function of the corrugation. In this way too, a double push-in sleeve can be produced from two identical sleeves 12 .

In the embodiment according to FIG. 17, two sleeves 12 '''arranged in mirror symmetry with respect to one another, as are already known from FIG. 12, are connected to one another with a composite tube 11 having three corrugations 16 in the same way as applies to FIG. 12 . In this way too, two identical sleeves 12 '''can be used to produce a double push-in sleeve which can be used in particular for connecting composite pipes 11 . Here, a welded mat 1 is used as an annular section 34 , which is pushed over the section of the composite tube 11 . Then the sleeves 12 '''are attached.

Claims (17)

1. A method for connecting a plastic tube with a plastic sleeve, characterized in that a fully formed sleeve ( 12 , 12 ', 12 '', 12 ''', 32 , 32 ') is used with a welding surface that a tube ( 11 , 11 ', 36 , 38 , 41 ) is used with a counter surface for the welding surface, the welding surface and counter surface are adapted to each other that a ge according to the welding surface and the counter surface formed electrically heatable welding mat ( 1 ) between the welding surface and the counter surface is brought and that the welding mat ( 1 ) is supplied with current and at least a part of the sleeve ( 12 ''', 32 , 32 ') against the pipe ( 11 , 11 ') or the sleeve ( 12 , 12 ' , 12 '') and the tube ( 11 , 36 , 38 , 41 ) are pressed against each other. 2. The method according to claim 1, characterized in that a welding mat ( 1 ) is used, which consists of an electrical resistance heating wire ( 2 ) with a plastic sheath ( 3 ) which with the plastic of the sleeve ( 12 , 12 ' , 12 '', 12 ''', 32 , 32 ') and the plastic of the tube ( 11 , 11 ', 36 , 38 , 41 ) is weldable, the heating wire ( 2 ) being laid to a mat. 3. The method according to claim 1 or 2, characterized in that a corrugated tube ( 11 , 11 ', 36 , 38 ) is used, the corrugation ( 16 ) of two flanks ( 17 , 18 , 17 ', 18 ') and a ring web ( 19 ) connecting them is limited, two adjacent corrugations ( 16 ) being connected to one another by means of a shaft base ( 15 ). 4. The method according to claim 3, characterized in that a composite tube ( 11 , 11 ') is used which has a smooth inner tube ( 13 ) which is surrounded by a corrugated tube ( 14 ). 5. The method according to claim 3 or 4, characterized in that the welding mat ( 1 ) bears at least against a flank ( 17 , 18 , 17 ', 18 ') of a corrugation ( 16 ). 6. The method according to any one of claims 3 to 5, characterized in that the welding mat ( 1 ) bears against a section ( 25 ) of a shaft base ( 15 ). 7. The method according to claim 5 or 6, characterized in that the welding mat ( 1 ) is approximately L-shaped in cross section. 8. The method according to any one of claims 3 to 7, characterized in that the welding mat ( 1 ) is applied at least against an outer ring web ( 19 ) of a corrugation ( 16 ). 9. The method according to claim 5 and 8, characterized in that a cross-sectionally approximately C-shaped, a corrugation ( 16 ) übergrei fende welding mat ( 1 ) is used. 10. The method according to any one of claims 1 to 4 and 8, characterized in that a welding sleeve ( 32 , 32 ') is used with a cylindrical welding surface and that a cylindrically shaped welding mat ( 1 ) between the welding surface and at least one ring web ( 19 ) a corrugation ( 16 ) is arranged. 11. The method according to claim 10, characterized in that a support ring ( 35 ) is arranged between two adjacent corrugations ( 16 ). 12. The method according to any one of claims 1 to 9, characterized in that an annular tube section ( 36 , 38 ) is used as the tube, to which two sleeves ( 12 ) are welded. 13. The method according to claim 12, characterized in that a segment ( 36 ) of a composite tube ( 11 ) with at least one corrugation ( 16 ) is used as the tube. 14. The method according to any one of claims 1 to 13, characterized in that the sleeve ( 12 , 12 ', 12 '', 12 ''') is made by injection molding. 15. The method according to any one of claims 1 to 13, characterized in that the sleeve ( 32 , 32 ') is produced by extrusion. 16. The method according to claim 14, characterized in that the welding mat ( 1 ) during injection molding with the sleeve ( 12 , 12 ', 12 '', 12 ''') is firmly connected. 17. The method according to claim 1, characterized in that part of the sleeve ( 12 ''', 32 , 32 ') is pressed radially against the tube ( 11 , 11 ') during welding.