DK150237B - PROCEDURE FOR CONTINUOUS PREPARATION OF A PIPE OR PIPE BASED WITH A FOAM SHOULDER INSULATOR - Google Patents

Description

150237 i

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for the continuous manufacture of a tube or tube bundle with a thermoplastic foam molding insulation sheath which is of the kind specified in the preamble of claim.

5 It is known, cf. DE Publication No. 1,915,768, to produce tubes of foam molding strips by deforming a cold foam fabric strip, wherein only the longitudinal edges are heated to welding temperature so that they can be welded together. This heating of the edges intended for welding is done only after the strip in cold condition has been folded into tubular form.

Therefore, this prior art can only be used for strips of a limited thickness in relation to the pipe cross-section and in relation to the elasticity of the foam material in question. Thus, in the known technique of the insulation, only insulating layers of very low thickness can be produced, in which the stress of the deformation creates stresses which seek to push the strip back from the folded state when the folding as in this known technique is done without prior heating the foam strip itself.

Accordingly, it is the object of the invention to provide a method of the kind mentioned in the first, wherein, in order to avoid said stresses, it is possible to produce tubes or tubes with insulating sheaths of a considerably greater thickness than heretofore, and this object is achieved by a method which according to the invention is characterized by the steps specified in the characterizing part of the claim. The short-term heating of the strip in the manner indicated allows the strip to be deformed across its longitudinal direction without creating any significant internal stresses.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail below with reference to the exemplary embodiment of the method according to the invention illustrated in the drawing. 1 schematically shows the process of the process on an apparatus for making foam insulated tubes; FIG. 2 is a schematic cross section through the apparatus along line 5A-A in FIG. 1, FIG. 3 is a schematic view of the apparatus according to section B-B according to FIG. 1, FIG. 4 is a schematic view through the apparatus of section C-C of FIG. 1, 10 FIG. 5 is a cross-section through an insulated tube bundle; and FIG. 6 is a cross section D-D of FIG. First

By means of the device shown in FIG. 1, a foam strip 2 of a thermoplastic and deformable material rolled up on a supply roll 1 is processed into an insulating cap. The strip 2 runs from the stock roll 1 via a deflection roll 3 onto a work table 4, on which e.g. there is a welding apparatus 5. This apparatus 5 is needed for joining an endless strip 2 when changing rollers. From the workbench 4, the strip 2 runs to a pair of guide rollers 6, 20 where it enters an endless band 8. The band 8 assumes the carrying function of the strip 2, and for this purpose the band 8 has a very rough upper surface, e.g. as with arbitrary grain size arbitrary. The strip 8 has a good mechanical adhesion to the strip 2. This is important as the strip at the subsequent heat treatment loses mechanical strength and otherwise there would be a danger that it would not be co-transported uniformly or would be stretched. The endless belt 8 is passed through the strip 2 through various apparatus, deflected at the end of a pressing mechanism 30 20 and returned to the guide rollers 6 again via a tension roller 17. The belt 8 is driven by a drive roller 22.

As the strip 2 is mounted and transported by the belt 8, it passes a heating means 7, see also the schematic cross-section according to FIG. 2. The heater can work 35 with air or rays. Upon passage, the strip is heated on one side, namely on its later inside, and thereby brought locally into the thermoplastic state; the heating in the cross-sectional thickness of the strip may only penetrate so far that the back, the later outside, remains practically cold and unplasticized, enabling the mechanical transport and adhesion on the belt 8. The heating temperature and the heating time depend on the properties of the foam and the thickness of the strip. A plasticization is desirable, i.e. heating until the thermoplastic state or transition into the thermoelastic state, which enters 10 to approx. the middle of the strip thickness, the plastic ring being in no case allowed to go so far as to destroy the foam structure. The heat treatment or tempering obtained by the strip at the passage of the heating means 7 is approximately similar to the annealing known from metal treatment. Consequently, the conveyor belt 8 runs over a work plate 13. The heating compartment is shielded by means of side shield plates 9, so that even in the edge regions a uniform heating of the strip 2 is ensured.

The strip 2, which is partially heated until plastic, is fed, 20 after leaving the heating element 7, to an apparatus which reshapes the strip so that the cross-section corresponds to that of the insulating jacket. In addition, the strip 2 runs into a mold funnel 10 which transforms it to the desired cross-section.

To the mold hopper 10 is directly connected a mold tube 14, the inner contour of which can be round, oval or other, which corresponds as far as possible to the desired cross-section of the insulating jacket. This cross-section is preferably adapted to the tube or tube bundle shape. However, the mold tube is at least at the top in the inlet region and also at the outlet end formed with a guide slot 14a, as can also be seen from the schematic cross section according to FIG. 3. In this guide slot 14a, at least in the inlet region, a guide rail 12, which simultaneously engages the shock assembly of the strip formed for the insulating jacket blank 2a and engages it so as to avoid twisting of the blank during the subsequent forward transport. The mold tube 14 is furthermore provided with a cooling means 11, preferably cooling air is blown into the mold tube 14. In this way, the workpiece 2a is again cooled and solidified as it passes through the mold tube 14. The belt 8 is also inserted into the mold tube 14 and adapts to the inner contour of the mold tube, so that pressure is also exerted by the conveyor belt 8 on the blank 2a, and despite the rubbing in the mold tube, a faultless transport takes place. The width of the strip 8 may be substantially smaller than the width of the strip 2, e.g. one-fourth to one-half of this width. At the end of the mold tube 14 additional guide rollers 16 may be arranged, but this is not necessarily necessary and depends on the insulating jacket to be manufactured. However, it is also convenient to place at the top of the outlet area a guide rail 15 which engages the impact assembly 39 of the blank 2a and prevents twisting thereof. This 15 is also important for the impact assembly of the workpiece to always leave the mold tube at the same location, and in this position comes to the subsequent apparatus for closing the workpiece 2a.

A tube 38 or more tubes 38a, b and c are then taken from one or more supply rollers 37 and inserted from above at a 20-point angle, through the open bump assembly into the insulating jacket blank 2a.

The tube 38 coming from one or more supply rollers 37 or tube bundles 38a, b and c, respectively, is conveniently guided over roll guide 40 or otherwise configured guide to provide a precise insertion into the insulating jacket blank and a precise feed to the closure described below. , eg. by welding the insulation jacket edge. The scattering means not shown in the drawing at the supply area of the pipe or tubes in the insulating sheath blank also contribute to a disturbance-free, precise operation.

The still open item 2a is then closed, e.g. by welding or bonding the shock assembly, possibly also by wrapping with a foil with adhesive edge or welding a slide closure. In the illustrated embodiment, a welding apparatus 19 is used to weld the blank 2a of the butt joint 39, as can also be seen in the cross section of FIG. 4. In order to obtain a flawless welding of the butt joint, the blank 2a is passed with the pipes 38a, b between an upper and lower flat clamping plate 18a, b which presses the blank to a roughly oval cross-section so that the major axis is horizontal. The shock assembly 39 is at the top so that the heating sword 19 engages the shock assembly and plasticizes the surfaces for welding. Furthermore, adjustable guide supports 36 are available on the sides as a side restriction. In this compressed cross-sectional form, the insulating sheath 2b welded to the butt joint is inserted directly into a holding pressure mechanism which, at a predetermined distance, holds the insulating sheath 2b in the predetermined position until the weld joint has become fixed. At the end of the pressing mechanism 15, the strip 8 conveying the insulating sheath 2b is then discharged and returned to the entrance, while the further transport of the insulating sheath 2b with the pipes 38a, b to a subsequent heating means 24 is effected by guide rollers 23.

The pressing mechanism 20 may also be designed in a different way to fulfill functional tasks. In FIG. 6 is a cross-sectional view of a pressing mechanism. Profiled rollers 41 and optionally smooth rollers 42, which may be arranged in axial direction several times in succession, fix and transport the insulating sheath 2a during the curing of the butt joint 39. The conveyor belt 8 takes shape after the rolling cross section corresponding to the insulating sheath which in part supports the tube 38.

However, a pressing mechanism simultaneously conveying conveyor belts 8, tubes or tubular bundles 38 and 38a, b, c and insulating sheath 2a during the curing of the connector assembly may also be designed in various other ways.

The rollers 23, which may be arranged according to the pressing mechanism 20, take over the task of the pipe guide. Then, optionally, another heating means 24 which performs the outer tempering of the insulating sheath 2b follows. Upon passage of the heating means 24, the insulating jacket is heated on its outer surfaces until plasticizing the outer skin, but only briefly, so that the foam structure is maintained.

5 Through this heat treatment, the last remaining stresses in the outer layer of the insulating jacket are tempered, so that no stresses remain which tend to return the jacket to planar strips.

This tempering step also leads to the breakdown of the longitudinal stresses and thus also contributes to the insulating sheath being as long as the pipe or pipe bundle. Upon subsequent truncation of a pipe section, there is thus virtually no shrinkage of the insulating jacket relative to the insulated pipe or pipe bundle. After passage of the heating means, the insulating jacket is cooled with the pipes again, for example, it is passed through a cooling pipe 27. The cooling pipe 27 can, for example, be driven by cooling air supplied via the inlet 26. In front of the cooling pipe 27, there is suitably a ring shield 25 which ensures a faultless supply. of cooling air. The cooling pipe 27 may be interchangeable and in its inner form adapted to the particular insulating jacket to be manufactured. The further away transport is via exit rollers 29. For flexible insulated pipes, the insulated pipe or pipe-25 can then be rolled up on e.g. a supply roll. In the case of rigid, insulated pipes, on the other hand, a cut-off occurs.

By means of the method according to the invention, a voltage-free and mold-closed insulation of a foam strip on pipes can be produced on the described apparatus. 1

By the method of the present invention, insulated tubes or tubes are produced in one line of work such that:

the subsequent mounting or subsequent application of insulating jacket to the pipes, respectively, the pipe bundles will lapse.