FI91374C - Method for continuous fabrication of a thermally insulated pipeline with a plastic sheath - Google Patents

Description

i 91374

A method for the continuous manufacture of a thermally insulated pipe with a plastic sheath.

The present invention relates to a method for the continuous transfer of liquids for the continuous manufacture of a thermally insulated pipeline with a plastic protective jacket, wherein the pipe to be foamed around it is continuously fed fastened in place with foam and fitted with a plastic cover.

Methods for the continuous as well as intermittent fabrication of thermally insulated pipelines with an external plastic sheath are known.

Various known continuous manufacturing methods comprise passing a pipeline with intermediate bridges together with a plastic film hose acting as a shield through a fixed mold tube, whereby the joining of the plastic strip and welding to the plastic hose takes place shortly before the fixed mold tube is inserted. The foamable plastic mixture is usually applied shortly before the overlapping edges of the plastic film strip formed in the plastic hose are joined and welded to the plastic film tape. During the transit time of the fixed mold tube, the annular space between the pipeline and the tubular outer sheath is then filled with foam. In connection with this method, it is possible to use an aluminum foil coated with copolymers on both sides instead of a plastic film hose, whereby the protective sheath after the foamed pipeline 30 is polished through a fixed mold tube is extruded by a DE (DE).

However, this continuous method has not been used in connection with larger diameter pipelines, because the frictional forces depending on the foam pressure present between the outer jacket 35 and the fixed mold pipe become too large even through the open pipe 2 of the fixed pipe. .

Instead of these continuous methods, a discontinuous method has been used, especially in the case of pipelines with a length of 6-12 m and a diameter of 20-60 mm 5, in which the pipeline is first provided at predetermined distances with foam-spaced gaps. The conductor structure thus formed is then gradually foamed in an inclined position. The thickness of the plastic hose is determined according to the foam pressure present in connection with this method, since its purpose is not only to form the outer sheath, but also to act as a "mold". In addition, the plastic hose must be strong enough to withstand the foam pressure. The disadvantage of this method 15 is therefore not only the necessity of using a thick plastic hose, but also the fact that flotation in an inclined position does not produce a uniform foam and, in addition, that the resulting foam has a specific gravity. Such an intermittent method is also not economically advantageous.

The object of the present invention is thus to provide a method by means of which it is also possible to produce pipelines with larger diameters in a continuous and economically advantageous manner while saving the material of the outer jacket 25 and forming a smaller layer of heat-insulating foam.

The object of the present invention is achieved in that a) thermally insulated pipelines are used as rigid, non-flexible pipelines with a larger diameter, preferably 20-60 mm and a length of 6-18 m, which are connected to each other by means of pipe connections and which are connected through a belt device, wherein the pipe fittings are cylindrical, which at their opposite ends are veu * Btet * u with axial gripping bores.

91374 3 wherein the diameter of the gripping boreholes corresponds to the outer diameter of the tubes and the outer diameter of the cylinders to the inner diameter of the mold channel of the double mold chain belt device, and 5 b) the foamable plastic mixture is made so that 10 c) an annular foamed, high specific gravity plastic sheath is extruded into the circumferentially foamed pipeline after it has left the double-molded chain belt device with a possibly cooled vacuum calibrated extruder.

15

The double molded chain belt device used according to the invention is known per se and is described, for example, by the continuous production of longitudinally cut foam insulation pipes according to DE-AS 12 66 485 continuous manufacture of pipe halves as a device for use.

Particular difficulties were caused in the continuous production of longitudinally slit foam plastic insulation pipes according to DE-AS 12 66 25 485 by holding the casting core over the entire length of the mold channel formed by both movable mold block chains and required for forming the foam insulation pipe. Namely, it has been found that although the core is firmly attached in both ends, the pressure exerted by the foam on the mold channel is so strong that the core cannot be held centrally in its entire length. In order to avoid such positional deviations, the core was additionally provided with a load-bearing fastening plate along its entire length, which extends in the direction of the rain in the mold channel between the opposite mold blocks.

The same drawback with respect to the positional deviation of the casting core also occurs in another known device, in which a fixed spindle pin is used as the internal core, which is attached only to the feeding head of the device and protrudes freely into the fixed or rotating outer mold. In this case, only a one-sided spindle pin is not able to provide sufficient stability to receive the pressure associated with the foam without a positional deviation. In this connection, reference is made to the structures according to the above-mentioned publication DE-PS 25 03 425, column 3, lines 49. Due to said problem with the spindle pin deviation, it has thus been proposed in connection with another known device according to DE-AS 21 65 584 to monitor the spindle pin deviation by means of a laser beam and to carry out the correction by means of harvesting and control elements.

However, with the aid of this auxiliary device, it is difficult to carry out the trouble-free repair of the solid inner core (spindle) simply because the device in question is very complex and prone to disturbance.

In accordance with the experience gained in connection with the use associated with the manufacture of foam insulation pipes cut in the longitudinal direction of said double molded chain belt devices. It has been surprisingly found that in connection with the method according to the invention, foam pipes insulated with foam are obtained by using a double-molded chain belt device, whereby the foam is also attached to the pipes of the largest diameter without concentrating the foam.

35 5 91374

The continuous method made possible by the use of a double-molded chain belt device allows continuous flotation of the pipelines, which has the advantage that the foam filler comprises a similar cell structure along its entire length without better specific gravity bubbles, thus achieving uniform mechanical resistance.

In addition, by means of the extruder connected after the double mold chain belt device and the associated calibration device 10, it is possible to economically achieve a foam jacket according to a model with a high specific gravity and a smooth outer surface. In connection with the method according to the invention, the foam-plastic jacket can also be made considerably thinner compared to the intermittent method described above, since the pressure present in the formation of the heat-insulating foam layer no longer has to be taken into account in the foam jacket. Thus, in the case of the method according to the invention, the effect of the foam jacket is reduced in relation to the diffusion-tightness and the protection afforded to prevent damage during transport and installation. The foamed protective cover reduces weight and price as well as increases flexibility. This jacket mainly comprises foamed polyethylene, polypropylene, polyvinyl chloride or a similar jacket with a specific gravity of preferably 3 to 500-800 kg / m 3.

Since the device used in the method according to the invention is arranged in such a way that the pipelines are automatically positioned concentrically - i.e. centrally - with respect to the outer jacket, the use of any baffles or centering supports which are only the most common in the present methods can be avoided. . In this way, the additional advantage is also achieved that several "cold bridges" are eliminated, whereby the thermally insulating pipeline prepared in accordance with the invention becomes further substantially better and cheaper.

The method according to the invention is suitable for use in connection with all heat-insulating pipelines, such as copper, steel or plastic pipes. Copper and plastic pipes can be supplied in rolls with a smaller sheet size, for example 22 mm sheet length, wound on rolls 50 m long or longer, after attaching the pan.

In the case of larger plastic pipes, this is best achieved by means of extrusion immediately before the use of the device according to the invention, whereby the treatment step of the pipes is omitted. After leaving the device according to the invention, the pipelines, which are no longer wound on a roll, are cut into thermally insulating pipelines of the desired length.

20 Rigid pipes, for example steel pipes or other metal pipes, are used in pieces of 12-18 m in length, which are connected to the device according to the invention shortly before feeding by means of special plastic sleeves as an "uncoated wire" and foamed. ". After the jacket coating, the pipes are again separated from each other by means of a special saw in the area of the sleeves, i.e. the pipe fittings. The pipe fittings are arranged in such a way that, after their removal, the ends of the pipes remain in the mucous foam insulation during installation of the insulating pipes, so that the pipes can be connected in an insulated manner tightly and permanently to each other with conventional pipe fittings.

35 7 91374 Any suitable plastic material provided with a blowing agent can be used for the thermally insulating foam layer using the corresponding output components forming each plastic material.

5 Depending on the intended use, the plastic material of the heat-insulating layer may be more flexible or stiffer. The use of flexible foams is recommended, for example, when "endless" thermally insulated pipelines are wound on a roll after leaving a device 10 according to the invention. In contrast, it may be advantageous to use hard foam in connection with rigid pipes.

Suitable foam materials are mainly polyurethane, polyisocyanurethane, polyolefin and in particular polyethylene or polypropylene foams or foams of their corresponding copolymers, as well as poly-styrene foam foams.

Polyurethane foams, both more flexible and Jay-grade grades, require a separating film which, together with the conduit, is fed to the double mold chain belt device so that it comes next to the mold blocks. The reno-like space between the separating membrane and the pipeline is then foamed.

As the separating film, any film sheet 25 can be used, such as a paper, plastic or metal film. To achieve the separating effect, it is sufficient to use a paper or plastic film as a separating film. If, on the other hand, additional effects are desired, such as thermal reflection or vapor barrier, it is preferable to use a metal film, for example an aluminum film coated on one or both sides with paper or plastic.

On the other hand, in the case of certain types of foam, such as polyethylene or polystyrene, it may not be necessary to use a separating film, since it may be sufficient for the mold block chains to be treated with a conventional mold release agent in connection with the return movement. If these mold-block chains are additionally cooled during the return movement, a relatively solid and almost homogeneous surface coating can be obtained in connection with a suitable method, in which case even the outer plastic sheath can possibly be dispensed with.

The placement of the foamable mixture in the annular space 10 between the guide tube and the separating film or the mold block chains takes place in a conventional manner, as described, for example, in the aforementioned DE-OS 33 07 865, whereby the foamable mixture is applied to the separating film before being connected to the film. The setting of the foamable plastic, in particular the components for forming the polyurethane foam, takes place in such a way that, after feeding the tubularly formed separating film with a slightly foamable mixture, the annular space between the guide tube and the separating film is simultaneously by means of a foam which has become load-bearing. The necessary measures are familiar to the person skilled in the art or can be carried out without difficulty.

If desired, when foaming the conduit, one or more detector leads may also be placed inside the foam at a certain distance from the conduit. These detector wires indicate and locate the moisture that has penetrated the foam layer.

The method according to the invention, of course, also allows the foaming of a plurality of mutually insulated conduits, which are then surrounded by a common plastic sheath. In this case, it is recommended to place the two conduits in one plastic sheath and to insulate these conduits with respect to each other, so that the cross-section of such a connecting structure is not at least circular, but oval. This arrangement can be used, for example, as a branch line from the main line to the consumers, in which case the supply and return water line is placed in one structural unit, which can be used to reduce transmission and installation costs.

Particularly preferred non-limiting embodiments of the present invention will now be described with reference to Figures 1-4.

Figure 1 schematically shows a bale view of a core part of a device according to the invention.

Fig. 2 schematically shows a cross-section of the mold blocks (5a, 5b, 5a / and 5b ') forming the double mold chains of the belt device (5) taken along the line 15A-A in Fig. 1.

Figure 3 shows a cross-section of a thermally insulated conduit 7 according to the invention.

Figure 4 shows a cross-section of the pipe connection piece 12.

In Figures 1-4 and later, the following numerals have the following meanings: 1 guide tube 2 separating film storage roll 3 separating film 25 4 flotation machine 5 formed mold channel 9 rack for control of mold block chains 10 thermally insulating foam layer 35 10 11 foamed plastic protective sheath 12 pipe connection piece

The double mold-chain belt device 5 schematically shown in Fig. 1 comprises two mold halves 5 divided longitudinally into individual mold blocks 5af 5b, 5a 'and 5b'f As these mold halves move in a straight line at a uniform speed. The individual mold blocks 5a, 5b form the required mold channel in a tightly compressed manner and are turned and guided outside the manufacturing area as separate mold blocks 5a ', 5b # (see Fig. 2) to the guide stand 9 in a manner known per se. The mold blocks 5a, 5b can be changed to accommodate the respective diameter of the conduit tube or the resulting thermal insulating foam jacket.

According to a preferred embodiment of the present invention, a flexible copper or plastic pipe is fed as a pre-sensitive from the storage roll via a guide and holding device to the directing device mixture and formed into a tube. After leaving the double mold chain-25 belt device 5, a guide tube 1 with a foam layer 10 is fed to an extruder 6 inside a vacuum calibration device, where the actual high-density foamed foam jacket 11 and brought to the site of use where it is wound from a roll to use.

According to another preferred embodiment of the present invention, rigid, non-rigid, 35 91374 11 m in diameter and 6 to 18 in. by holding the holding-5 device together with the separating film 3 and the foamable mixture as described above. In order to guarantee the operation of the JAT image, the insulated conductor pipes 1 are connected in series together by means of the pipe fittings 12 shown in Fig. 4 and are passed as a seemingly endless pipe 10 through a double mold chain belt device 5. The outer and inner diameters of the pipe fittings are adapted to each conduit 1 and the desired heat-insulating foam layer 10. After leaving the extruder 15 6 equipped with the vacuum calibration device and attaching the plastic sheath 11, the invisible pipe fittings 12 are sawn by means of a guided saw transversely transversely to the longitudinal axis. The thermally insulated conduits thus re-separated are led via a support bracket to a packaging or bundling unit. The cut-through pipe fittings are preferably connected to the thermally insulated conduits until installation and are only removed shortly before the installation of the conduits.

Of course, the pipe fittings 12 can also be removed directly from the thermally insulating conduits 7 leaving the vacuum calibration device of the extruder 6, whereby these intact pipe fittings 12 can be removed by a separator with a plastic protective jacket 11 on top of them. The thermally insulating conduits 7 without the pipe fittings 12 can then be provided with other types of protective sheaths until the installation of the transport handles, if desired.

Another advantage provided by the pipe fitting 12 used in accordance with the invention is that, after removal of the pipe fitting 12, the ends of the pipeline are immediately free of the usual durable and tight pipe socket connection 5 required for myohemrain.

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Claims (4)

91374 A method for the continuous production of a liquid-insulated pipeline with a plastic sheath for transferring liquid or gaseous, heated or cooled intermediates, wherein the pipeline to be foamed around it is continuously fed to the pipeline by means of a parallel-line, double-molded chain belt device. 10 and provided with a plastic sheath, characterized in that a) rigid, non-flexible pipelines with a relatively large sheet size, preferably 20-60 mm and a length of 6-18 m and 13 with pipe fittings (12) are used as heat-insulated pipelines (1) connected to each other and guided as a visually unattached conductor through the double mold chain belt device (3), the pipe fittings being cylinders provided with axial 20 feartuin bores at opposite ends, and (b) the foamable plastic composition is made to harden at least to such an extent that it supports the pipeline (1) at the latest when the pipeline (1) due to its weight, and c) the double molds in the circumferentially ventilated pipeline (1) are extruded with 30 possibly cooled vacuum calibrated extruders (6) by means of a ring nozzle. A method according to claim 1, characterized in that the difference between the mold blocks (5a, 5b) of the tube sleeve (1) and the double mold chain belt device (5) is set before the flotation of this selection space in the double mold chain belt device (5). film (3), preferably made of paper, plastic or paper-coated aluminum film or plastic, and that the wall-like space of the pipeline (1) and the separating film (3) is foamed only after this. Method according to Claims 1 and 2, characterized in that the ferrous state of the pipeline (1) and the separation film (3) is foamed with a release mixture forming a polyurethane foam. Method according to Claims 1 and 2, characterized in that a polyolefin with a blowing agent, in particular polyethylene or PUC, is used for the production of the foamed plastic protective sheath (11). 91374