DE2532406A1 - METHOD AND DEVICE FOR MANUFACTURING PIPES FROM STRIPS OF FOAM - Google Patents

Description

OZ no .: 75063

DYNAMIT NOBEI, AKTIENGESELLSCHAFT Troisdorf Bez. Cologne

Method and method of making tubes from strips

made of foam

The subject matter of the invention relates to a method and a device for the production of pipes from strips of a thermoplastic and deformable foam, ζ.3. V / calibration PVC, crosslinked or uncrosslinked polyethylene foam through Forming the strip to the pipe cross-section and closing the Butt seam "for example by welding or gluing,

Pipes made of foam, thin-walled or thick-walled with smaller or larger diameters, are used in particular for insulation corners against cold or heat, e.g. for the entire sanitary installation such as hot water, cold water, waste water, heating pipes, cold pipes, etc. Such pipes can either be extruded directly from Schaxunstoff. However, it is also possible to produce such tubes from foam strips. The latter is particularly suitable for foams that cannot be extruded directly, such as, for example, crosslinked polyethylene foams. The foam strip is produced as a single product either by extrusion with replicas or in the coating process, the latter for example in the case of soft PVC foam.

It is known to make pipes from strips of deformable thermoplastic Manufacture foams by the fact that the foam strips are bent and folded flat v / ground, with the butt joint is welded or glued. The resulting hollow cross-section is then pressed on. The on this However, tubes made from strips have none round cross-section, but tend to be one

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oval cross-section, which turns out to be particularly disadvantageous when, in a later slitting of the shaped tubes, - as Assembly aid the slot seam diverges, i.e. is not form-fitting. There is also the risk that due to the tensions remaining in the tube formed in the Glued or welded seam partly opens again, partly not form-fitting connected is.

The invention is based on the object of a tube made of strips of Schaura fabric to create that after the completed shaping is also tension-free, so that the form-fit is retained even when the pipe is subsequently further processed and in use remain.

This object is achieved according to the invention in that the Strip on its later inner side of the pipe before reshaping and after the butt seam has been closed after reshaping the outside of the pipe briefly bj s in the thermoela.stischen or thermoplastic state is heated. These heat treatments, which correspond approximately to a tempering, v / grounding carried out so that the heating in each case only over a part of the thickness of the cross-section of the strip penetrates, the plr.stiffening is only pushed so far that the foam structure is not destroyed. The heating temperature and the heating time depend on the material of the foam and the foam thickness. The stepwise heat treatment provided according to the invention leads to a stress-free tube, which also after its later cutting open (longitudinal slitting) no longer has the tendency to return to its original strip foria. Furthermore, with the method according to the invention, forming in the thermoelastic / thermoplastic state is possible, also relatively to shape hard foams into tubular bodies with relatively small inner diameters or thick walls for small ones Pipe diameters.

In a further development of the method according to the invention, it is provided that the strip passes through a shaping tube after reshaping and is thereby cooled. The intended first heat treatment not only does the later inside of the pipe

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tension-free, but at the same time facilitates forming into the Pipe cross-section. After forming into the pipe cross-section, cooling is carried out at the same time, so that the formed Tube can solidify when passing through a mold and become dimensionally stable. Y / pus is provided that the reshaped and by cooling re-solidified tube is pressed into an oval cross-section, with the long axis of the ellipse horizontal and on The upper end of the vertical short axis of the ellipse is the butt seam to be connected by welding or gluing. In this way, the butt seam is perfectly aligned lengthways allows their entire area and thus a perfect connection can be achieved.

Since the first heat treatment carried out leads to a relative softening of the foam strip, a further one is required Feature of the invention provided that the strip including up to the closure of the butt seam continuously with a conveyor belt with a roughened surface is moved, wherein the strip adheres to the rough surface. To this This avoids lengthening or stretching the foam strip and ensures even transport.

According to the invention, a further process step is provided: that the pipe welded or glued at the butt joint is cooled after the external heat treatment, and preferably at a point that does not form the butt seam, is slit again in the longitudinal direction. To close this slot you can a slide fastener or tape with an overlap can be attached to the pipe. The pipe produced in this way is suitable advantageous for use for insulation purposes, where the slot means an assembly aid and the attached fasteners allow easy closing after assembly of the pipe. The pipe produced according to the invention is in its final state tension-free and form-fitting.

To carry out the method according to the invention, a device is proposed which is characterized in that an endless belt with a rough surface for transport

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of the continuously tapering strip by a heating device, a molding funnel, a molding tube equipped with a cooling device, a device for closing the butt seam and a pressing device is provided. Here ¹ , the shaped tube can be designed with a guide slot on the top side at least at the inlet and outlet end, in that a guide rail can be inserted into the butt seam of the shaped tube. To establish a proper connection of the! Butt joint means, for example hold-down plates, are provided for deforming the pipe into an oval cross-section in the area of the device, for closing the butt joint. In this way becomes; achieved that the surfaces of the butt joint perfectly! and lateral pressure is exerted on the butt joint.

I In a further development of the device it is provided that the pressing device a heating acting on the outside of the pipe; device is downstream to which a cooling section is attached. ; closes. Next is a slitting knife for slitting the j heat-treated and cooled tube provided, so that in I the continuous manufacturing process at the end of the finished ■ and ready-to-use pipe is available in the desired lengths.

; The invention is shown in the drawing using an exemplary embodiment and is explained in more detail below on the basis of this. ; Show it

Figure 1 is a schematic representation of a device for ^; Manufacture of pipes from foam strips,

Figure 2 shows a schematic cross section through the heating device according to section A-A of Figure 1,

Figure 3 is a schematic view of the shaped tube after section B-B according to Figure 1,

FIG. 4 shows a schematic view through the connecting device according to section C-C of Figure 1 and

Figure 5 is a schematic view of the pressing device, Section D-D according to Figure 1.

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With the device shown in FIG. 1, foam strips are grounded 2 made of a thermoplastic and deformable material, which are wound up on supply rolls 1, to form tubes processed. The strip 2 runs from the supply roll 1 over the wrapping roll 3 onto the work table 4 on which, for example, a gluing device 5 is provided. This gluing device 5 is required for endless joining of the strips 2 when changing rolls. From the work table 4, the strip 2 runs through the Guide roller pair 6, where it runs onto the endless belt 8. The belt 8 takes over the driver function for the strip 2, the tape is used for this purpose. 8 has a very rough upper side, e.g. as with emery belt with any grain. This tape 8 v / e has good mechanical adhesion to the strip 2. This is important because during the subsequent heat treatment the Strip loses mechanical strength and otherwise there would be the risk that it is not transported evenly or but would stretch. The endless belt 8 is guided along the strip 2 through the various devices and is at the end deflected by the pressing device 20 and returned to the guide rollers 6 via the tensioning roller 17. The drive for the belt 8 takes place via the drive roller 22.

After the strip rests on the belt 8 and is transported, the strip passes through the Heizvorr.i "HTUR ■ 7» see also schematic cross section according to Figure 2. The heating device can with air, radiators were operated ^etc:. '~ N When. The strip is traversed on one side, ie uiu seii later. Rohrinnenceite erwsruit and in the i, Ι) ν;. "Λτ.ορ.1ίΓλ '.- ΐίρ · ..Ί ,. η to ⁱ iana, with ci.is warming just so wait üu> rc: -m nod (■■■ · .., "■ -.- section of the strip penetrates that the uüc Lsc -." ■ - <? , the ^ yo ■■ \ -ir- KohrauSeite, practically still cold and prim ^ st; xi.z.ier t bieiut unci the mechanical transport and dit Km i-tuug uut "oe;: · P ^ uin β erraog] j . .cht vie heating temperature and the Heizv.eit "· outlaw on the properties of the foam and the thickness of the St rc ons if this is a total of a Plast.i · Iz.i - *. '.mg, d, h, a heating up to the therriioelastic 07λ ·. Übe · ang in the? j thermoplastic state up to etv / n to the holding o- thickness of the strip wish- · -. ■ -:., where ^ u- fins ti.fixier ^ ■■ .; koiuf.-vf, -Ί1 a

} 3 / ί; V.

may go so far * that the foam structure is destroyed. This heat treatment applied to the strip as it passes through the Heating device 7 experiences, corresponds approximately to tempering. That Conveyor belt 8 runs here over the worktop 13. The The boiler room is shielded by the side shielding plates 9, so that even heating of the strip in the edge areas is ensured.

The partially heated up to the plasticization strip 2 is after ■ ferHassai the heating device 7 of the device for reshaping in the Pipe cross-section fed. Here the strip 2 runs into the Form funnel 10, which reshapes it to the pipe cross-section. The forming tube 14 directly adjoins the forming funnel 10, However, the top side at least in the inlet area and also ejn The outlet end is formed with the guide slot 14a, such as can also be seen from the schematic cross section according to FIG. This guide slot 14a engages at least in the inlet area the guide rail 12, which at the same time engages in the butt seam of the strip formed into the tube 2a and this marked, so that a twisting of the formed tube after - ^ - subsequent further transport is avoided. The forming tube 14 is further provided with the cooling device 11, cooling air being blown into the forming tube 14. That way is ensured that the strips formed into the tube 2a at Passing through the shaped tube 14 cools back to room temperature and solidifies. The band 18 is also inserted into the forming tube 14 introduced and adapts to the curvature of the shaped tube, whereby a pressure of the shaped tube 2a on the conveyor belt 8 is exercised, so that perfect transport takes place despite the friction in the forming tube. The width of the band 8 can be much smaller than the width of the strip 2, for example a quarter to a third of the same. Guide rollers 16 can also be arranged at the end of the shaping tube 14, but this is not absolutely necessary and depends on the foam tube to be produced. However it is also useful to have a guide rail on the top in the run-out area 15 to be provided, which engages in the butt seam of the shaped pipe 2a and prevents twisting of the pipe.

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253240b

j -7-

This is also important so that the butt seam of the pipe always leaves the molded pipe at the same point and in ι this position of the following device for locking the butt seam can be fed.

The still open formed pipe 2a can now be ^{subjected to further treatments 1} , such as welding the butt seam, gluing the butt seam, wrapping with a film with an adhesive edge, welding on a slide fastener, etc. In the embodiment shown, a welding device 19 closes for welding the butt seam of the shaped tube 2a, as can also be seen from the cross section according to FIG. In order to achieve perfect welding of the butt joint, the preformed tube 2a is guided between an upper and lower hold-down plate 18a, b, which press the tube into an oval cross-section, the long axis of the ellipse being arranged horizontally. The butt joint of the shaped tube 2a is on the top side, so that the heating blade 19 engages in the butt joint and plasticizes the surfaces so that they weld. Furthermore, laterally adjustable guide supports 36 are provided as side delimitation. In this compressed oval cross-sectional shape, the pipe 2b welded shut at the butt joint is inserted directly into the pressing device 20, which holds the pipe in the predetermined position over a predetermined distance until the weld is solidified. At the end of the pressing device, the tape 8 is pulled off the pipe 2b and returned to the exit, while the pipe 2b is transported further to the subsequent heating device 24 by means of the guide rollers 23.

In the figure 5 is a cross section through the pressing device 20, wherein the oval cross-section of the pipe 2b welded shut at the butt seam 35 can be seen, on the one hand through the lateral adjustable limit 21 and on the other hand held by the upper and lower belt 20a, b of the pressing device 20 v / ird.

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The guide rollers 23, which are arranged downstream of the pressing device 20, can at the same time take on the task of rounding the oval tube up again by applying pressure. Then follows ^! second heating device 24, which carries out the external heat treatment of the pipe 2b I. When passing through the heating device 24 this will be! Tube heated on its outer surface until the outer skin is plasticized, but only for a short time, so that the foam structure is retained. This heat treatment removes the last remaining stresses in the pipe in the outer layer; annealed so that no tensions remain in the pipe which would want to restore it to the flat strip. After leaving the heating device, the tube is cooled down again, it being guided through the cooling tube 27, for example. The cooling tube 27 can be operated, for example, by means of cooling air which is returned via the inlet 26. In front of the cooling pipe 27, a screen 25 is expediently arranged, which ensures a perfect supply of the cooling air. The cooling tube 27 can be exchangeable and its diameter can be adapted to the respective tubes to be produced. The further removal of the pipe takes place via the take-off rollers 29, which are driven by the drive 31 and the swiveling driver roller 28 on the upper side a point that does not correspond to the butt joint, slit in the longitudinal direction. To cut the slotted tube 2c to length, the guide 32, for example a guide bushing, is provided, to which the transverse cutting knife 33 is connected. The deflected pipe sections are placed on the tilting device 34 for storage

brought.

With the method according to the invention, a stress-free and form-fitting tube is made on the device described Foam strips can be produced, the subsequent slitting has a form-fitting slot which, for example, glued or glued over the outside or with during later use. can be provided with a slide lock or source welded.

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Claims (11)

Patent claims: 1. Method of making tubes from strips of a thermoplastic and deformable foam, e.g. soft PVC, crosslinked or uncrosslinked polyethylene foam, by reshaping the strip to form a pipe cross-section and closing it the seam, for example by welding or gluing, characterized in that that the strip is on its later Rchrinnseite before reshaping and after the closing of the butt seam on its pipe outside following the reshaping briefly up to the thermoelastic or thermoplastic state is heated. 2. The method according to claim 1, characterized in that the strip passes through a shaped tube after reshaping and thereby is cooled. 3. The method according to claim 1 or 2, characterized in that the welded or glued pipe at the butt seam the external heat treatment is cooled and preferably at a point that does not form the butt seam, again in the longitudinal direction is slotted. 4. The method according to claim 3, characterized in that a slide fastener or an adhesive tape to close the slot is attached to the pipe with an overlap. 5. The method according to any one of claims 1 to 4, characterized in that that the strip, including up to the closing of the butt seam, is continuously roughened with a conveyor belt Surface is moved, with the strip adhering to the rough surface. 6. The method according to any one of claims 1 to 5, characterized in that that the reshaped tube, which has solidified again by cooling, is pressed into an oval cross-section, where- 609883/0721 with the long elliptical axis horizontally and at the upper end of the vertical short elliptical axis that by welding or gluing butt seam to be connected is arranged. 7. Device for performing the method according to one of claims 1 to 6, characterized in that an endless Circumferential belt with a rough surface for transporting the continuously running strip through a heating device, a molding funnel, a molding tube equipped with a cooling device, a device for closing the butt joint and a pressing device is provided. 8. Apparatus according to claim 7, characterized in that the shaped tube at least at the inlet and outlet ends on the top is formed with a guide slot, in which a guide rail up into the butt seam of the molded Tube is insertable. 9. Apparatus according to claim 7 or 8, characterized in that means, e.g. hold-down plates, for deforming the Tube are provided in an oval cross-section in the area of the device for closing the butt seam. 10. Device according to one of claims 7 to 9 »characterized in that the pressing device has one on the Subordinate heating device acting on the outside of the pipe, which is followed by a cooling section. 11. Device according to one of claims 7 to 10, characterized in that a longitudinal cutting knife for slitting of the heat-treated and cooled tube is provided. Troisdorf, July 14, 1975
MG / Rl. OZ no .: 75063 & 098837077Ϊ