DE2654879C2 - Process for the continuous production of a pipe provided with an insulating sleeve made of foam plastic - Google Patents

Description

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The object of the invention relates to a method for continuously producing a with an insulating sleeve made of preferably closed-pore thermoplastic foam plastic tube, wherein the insulating sleeve from a flat strip of foam plastic by deforming transversely to it Longitudinal extension around a continuously inserted pipe and sealing of the butt seam by welding or gluing is obtained.

Insulating sleeves made of foam plastic, thin-walled or * thick-walled with smaller or larger diameters are especially used for insulation purposes against cold or heat, e.g. B. for the entire sanitary installation such as hot water, cold water, sewage, heating pipes, Cold pipes etc. used. Such insulating sleeves can either be extruded directly from foam will. However, it is also possible to make them from strips of foam. The latter is particularly useful for foams that cannot be extruded directly, such as crosslinked polyethylene foams. The foam strip is produced in the form of a sheet product either by extruding it with Nach * foam or manufactured in a coating process, the latter z. B. with soft PVC foam, from DE-OS 15 768 it is known to produce insulating sleeves made of strips of deformable thermoplastic foams make that the foam strips

bent and folded flat, with only the longitudinal edges forming the butt seam at welding temperature heated and then welded or glued. With this cold deformation process In particular, insulating sleeves with larger diameters and thin walls can be produced because with thicker walls or smaller diameters, the resilience of the foam is disadvantageous noticeable b? w. Wrinkles in the shawls be molded.

Also from DE-GM 75 09 227 is an insulating sleeve made of a closed-cell foamed plastic known for the pipe insulation, which is slotted in the longitudinal direction and in which this slot through a The welded slide lock is lockable.

These known insulating sleeves are then pushed onto the pipes to be insulated and subsequently then the longitudinal slot is then closed, for example by welding, gluing or by means of the above-mentioned slide lock.

The invention reads the object that To simplify the manufacture of the insulated pipe and to make it easier to assemble for installation. Of In addition, the insulating sleeve should be form-fitting and true to shape, as well as the production of insulation allow small diameters and thick walls at the same time.

The object is achieved in that the strip of foam plastic on its die The side that later forms the inside of the insulating cover briefly extends to the thermoelastic or thermoplastic side State heated and then preformed to the insulating sleeve cross-section, then this insulating sleeve preform is cooled somewhat and inserted through the open butt seam of the insulating sleeve preform and the tube then the butt seam of the insulating sleeve is closed.

The aforementioned short-term heating of the later inner side of the insulation up to the thermoelastic or thermoplastic state causes an increase in flexibility, so that even small pipes or small Tube bundles can be provided with a relatively thick insulating sleeve. But this also causes warming at the same time a lowering of the tensile strength of the foam strip, so that when the insulating sleeve is deformed as a result of unavoidable friction with device parts, unwanted longitudinal and transverse deformations were created. However, this is achieved by a circulating conveyor belt with a rough surface prevents the transport of the strip, especially when it is heated. This avoids the pre-stretching of the insulating sleeve. Tube or tube bundles and insulating sleeves are practical of equal length. When an insulated tube bundle is later cut off, the Insulation against the inner tube or the inner tubes avoided.

According to the invention, the production of the insulating sleeve from a flat foam plastic strip combined with the continuous introduction of the pipes to be insulated and subsequent closing the butt seam of the insulating sleeve. In the method proposed according to the invention, the isolated Pipes can be cut to length from a supply roll directly or for the supply store as required. It is possible, not only to enclose one pipe with an insulating sleeve, but at the same time two or more pipes that are too a tube bundle are combined with a

to surround a single insulating sleeve at the same time. With the method according to the invention it is also possible to provide more than one insulating sleeve, since the insulated tube or tube bundle can be surrounded again with a further insulating sleeve. Must be sen the advantage over the known methods in which the need to be plugged to be insulated pipes, either in sections in the already closed insulating sheaths in the longitudinal direction or in which this slot each ^f in slotted insulation sleeves closed-ÜR the individual insulated pipe '° is obviously .

Since in the method according to the invention no fixed Connection between the insulating sleeve and the pipes located inside is established, there is the advantage during assembly that the insulating sleeve is pushed back at the coupling ends can be and thus the pipe ends are exposed during assembly, after completion of the assembly however, the coupling point through the insulating sleeve again covered and thus automatically isolated.

It is also possible, after closing the butt seam of the insulating cover around the pipes, to place the insulated pipe or the isolated dysentery bundles again briefly on the outside of a heat treatment (tempering), if necessary with subsequent cooling, to be subjected to residual stresses from the insulating cover remove.

In a further development of the method according to the invention, it is also proposed that, in the case of several pipes to be enveloped, the butt seam of the insulating sleeve is laid in the area between two pipes where the insulating sleeve does not come into contact with the pipes. In this way, a good compression of the insulating sleeve in the area of the butt joint and thus a secure closure is possible without z. B. ^ the pipes inside can be damaged by a welding wedge.

The inventive method for the continuous wrapping of pipes at the same time Manufacture of the insulating sleeve is for both pliable and +0 can also be used for rigid pipes. As flexible tubes for the method according to the invention in particular Plastic pipes made of radiation-crosslinked polyethylene are proposed. | But it is also possible to be rigid Pipes, e.g. B. to isolate copper pipes with the method according to the invention.

When using flexible Rohi s it is proposed that in a horizontal production of the insulating sleeve, a flexible tube is inserted from above at an acute angle into the insulating sleeve w ^ .- d. It is also possible here to supply several flexible tubes parallel to one another to the insulating sleeve from several supply rolls, which are, for example, anchored next to or on top of one another. If several tubes are fed individually to the insulating sleeve in parallel to one another and are arranged in a tube bundle, it is possible to fix them in sections, for example using an adhesive tape that is folded over on the outside, and thus to insert them into the insulating sleeve. This means that their position in relation to one another is also more ^{clearly defined within the b0} insulating sleeve.

Furthermore, it is advantageous that after closing the insulating sleeve around the pipe or pipes a external heat treatment, briefly reaching the plasticizing temperature of the foams, is carried out, With this post-curing, stresses are released from both the insulating sleeve and possibly removed from the enclosed pipe.

The invention is shown in the drawing using an exemplary embodiment and is based on this explained in more detail below. It shows

F i g. I a schematic representation of the method v process on a device for the production of pipes insulated with foam strips,

2 shows a schematic cross section through the device according to section AA in Fi g. I ₁

F i g. 3 shows a schematic cross section of the device according to section BB in FIG. 1,

4 shows a schematic cross section through the Device according to section C-Cin F i g. 1 and

5 shows a cross section through an insulated tube bundle.

F i g. 6 shows a cross section according to DD in FIG. 1.

With the in FIG. 1 device shown, foam strips 2 made of a thermoplastic and deformable material, which are wound on supply rolls 1, processed into insulating sleeves. B. a welding device 5 is provided t * \. This device 5 is required for the endless joining of the ends of the strips 2 when changing rolls. From the work table 4 the strip 2 runs through the pair of guide rollers 6, where it runs onto the endless conveyor belt 8. B. as with emery tape with any grain size. This conveyor belt 8 exhibits good mechanical adhesion to the strip 2. This is important because the strip loses its mechanical strength during the subsequent heat treatment and there would otherwise be the risk that it would not be transported uniformly or would be stretched. The endless conveyor belt 8 is guided with the strip 2 through the various devices and deflected at the end of the pressing device 20 and returned to the pair of guide rollers 6 via the tensioning roller 17. The drive for the conveyor belt 8 takes place via the an'nebs rollers 22.

After the strip rests on the conveyor belt 8 and is transported, the strip passes through the heating device 7, see also the schematic cross section according to FIG. Z The heating device 7 can operated with air emitters etc. When passing through the strip becomes one-sided, i. H. on his later heated inside and put in the thermoplastic state, the heating just so that the back penetrates far into the strip. - the later outside - that remains practically still cold and unplasticized and the mechanical transport and the adhesion on the conveyor belt 8 is made possible. The heating temperature and the heating time depend on the properties of the foam and the thickness of the strip. This is a total of plasticization, i. H. a heating up to the thermoelastic or transition to the thermoplastic state up to about half of the peck of the strip is desirable, whereby the plasticization must not go so far, that the Schaumstoffsllruklur is destroyed. This heat treatment applied to the strip when passing through the heating device 7 experiences corresponds approximately to tempering. The conveyor belt 8 runs here over the Countertop 13th De. ”The heating room is through the side Shielding plates 9 shielded, so that even heating in the strip in the edge regions

rich is assured.

The strip 2, which is partially heated to the point of plasticization, is fed to the device for reshaping into the insulating sleeve cross-section after it has left the heating device 7. Here, the strip 2 runs into the forming funnel 10, which reshapes it into the desired cross section. The shaped tube 14 directly adjoins the shaped funnel 10, the inner contour of which can be round, oval or otherwise largely correspond to the desired cross section of the insulating sleeve. [This cross section can advantageously be adapted to the shape of a tube or tube bundle. The shaped tube is, however, formed with the guide slot 14a on the upper side at least in the inlet area and also at the outlet end, as can also be seen from the schematic cross section according to FIG. In this guide slot 14a, at least in the inlet area, the guide rail 12 engages and simultaneously marks the butt seam of the strip formed into the insulating sleeve preform 2a, thus avoiding twisting of the preform 2a during subsequent further transport. The shaped tube 14 is also provided with the cooling device 11, with cooling air preferably being blown into the shaped tube 14. In this way it is ensured that the preform 2a cools down again as it passes through the molding tube 14 and solidifies somewhat. The conveyor belt 8 is also inserted into the mold tube 14 and adapts to the inner contour of the mold tube, whereby a pressure of the preform 2a is exerted on the conveyor belt 8, so that perfect transport takes place despite the friction in the mold tube. The width of the conveyor belt 8 can be significantly smaller than the width of the strip 2, for example a quarter to a half of the same. At the end of the shaped tube 14, guide rollers 16 can also be arranged, but this is not absolutely necessary and depends on the insulating sleeve to be produced. However, it is also advisable to provide a guide rail 15 on the top side in the outlet area, which engages in the butt seam 39 of the preform 2a and prevents it from twisting.This is also important so that the butt joint 39 of the preform 2a always leaves the molded tube at the same point The position of the following device for closing the preform 2a is now the tube 38 or the tubes 38a, b. c is drawn off from one or more supply rolls 37 and introduced from above, tapering at an acute angle, through the open butt seam into the insulating sleeve preform 2a

The tube 38 coming from one or more supply rolls 37 or the tube bundles 38a, b, c are expediently passed over roller guides 40 or differently designed guides in order to ensure precise introduction into the insulating sleeve preform and precise feed for the connection described below, e.g. B. by welding the insulating envelope edges to ensure. Spreading, not shown here, in the area of the introduction of the pipe or the pipes into the insulating sleeve preform also contribute to a precise, trouble-free workflow.

The preform 2a which is still open is now closed, for example

Approximately example follows a welding device 19 for welding the butt seam 39 of the preform 2a, as can also be seen from the cross section according to FIG. In order to achieve a perfect welding of the butt seam, the preform 2a with the tubes 38a, b is guided between an upper and lower low hall sheet I8a, b , which press the preform 2a into an approximately oval cross-section, the long axis being arranged horizontally Butt joint 39 is on the top, so that the welding device 19, which can be designed as a heating blade, 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 cross-sectional shape, the insulating sleeve 2b welded shut at the butt seam is inserted directly into the pressure device 20, which holds the insulating sleeve 2b in the predetermined position over a predetermined distance until the weld seam solidifies is. At the end of the pressing device 2ö, the conveyor belt 8 transporting the insulating sleeve 2b is pulled off and returned to the exit, while the insulating sleeve 2b with the pipes 38a, b is transported to a subsequent heating device 24 by means of the guide rollers 23

The pressing device 20 can also be designed in a different way to fulfill the functional tasks will. FIG. 6 shows the cross section of a pressing device. Profiled rollers 41 ω and possibly smooth rollers 42, which are in axial Direction can be arranged multiple times one behind the other, fix and transport the insulating sleeve 2a during the hardening of the butt seam 39. The conveyor belt 8 is placed on the roller cross-sections correspondingly to the insulating sleeve, which in turn is partially supported on the pipe 38

A pressing device which simultaneously transports conveyor belt 8. Tube 38 or tube bundle 38a, b, c and insulating sleeve 2a while the connection seam is hardening can, however, also be designed in different ways.

The guide rollers 23, which can be arranged downstream of the pressing device 20, take on the task of guiding the pipe. Then, if necessary, the second heating device 24 follows, which carries out the external heat treatment of the insulating sleeve 2b of the insulating sleeve in the outer layer of the remaining tensions are annealed so that no tensions remain, which want to reset them to a flat strip. This tempering process also leads to the reduction of the longitudinal stresses and thus also contributes to the fact that the tube or tube bundle is of the same length as the insulating sleeve. After leaving the heating device 24, the insulating sleeve with the tubes is cooled down again, being guided through the cooling tube 27, for example. The iili

Cooling pipe 27 can be operated, for example, by means of cooling air by welding the βί, which is supplied via the inlet 26

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Enveloping with a film with adhesive edge, welding 25 arranged the proper feeding of the a sliding lock etc. In the execution shown, cooling air ensures the cooling pipe 27 can be exchanged

be bar and in its inner form the respective
Isolierhiilleii to be produced are adapted. Of the
further removal takes place via the take-off rollers
29. In the case of flexible, insulated pipes, then
then the insulated tube or tube bundle z. B.
be wound up on a supply roll. At stare
insulated pipes are cut to length.

Will require rigid pipes instead of flexible pipes, e.g. B.
Isolate Kupferronre, so it is appropriate to this

To transport pipes in one level, while the elastic and deformable insulating sleeve under one at an acute angle is fed to the straight pipe. It is also possible to do this directly from a Fastening process coming pipes, z. B, in front of the extruder coming extruded plastic pipes with an insulating sleeve according to the method according to the invention Mistake;

On this .1 Bliitt Zcichmiimen

Claims (4)

Patent claims: 1. A method for continuously producing a with an insulating sleeve from preferably closed-cell thermoplastic foam plastic provided tube, the insulating sleeve from a flat strip of foam plastic by deforming it transversely to its longitudinal extension around a continuously inserted pipe and sealing the butt seam by welding or Gluing is obtained, characterized in that that the strip of foam plastic on its inner side which will later form the insulating cover Page briefly heated up to the thermoelastic or thermoplastic state and then is preformed to the insulating jacket cross-section, then this insulating jacket preform is cooled somewhat the pipe is inserted through the open butt seam of the insulating sleeve preform and then the fabric seam of the insulating sleeve is closed. 2. The method according to claim 1, characterized in that in one in a horizontal plane ongoing production of the insulating sleeve in a flexible tube from above at an acute angle the insulating sleeve is inserted. 3. The method according to claim 1 and 2, characterized in that with several to be enveloped Pipes the butt seam of the insulating sleeve is laid in the area between two pipes where none Contact of the insulating sleeve with the pipes takes place. 4. The method according to claim 3, characterized in that a plurality of tubes guided separately and / u arranged in a tube bundle, optionally in sections, for example dt -ch an externally folded adhesive tape, are inserted into the insulating sleeve. 10