DE3235635C2 - Method and device for the continuous production of thick-walled multilayer insulating pipes from thermoplastic foam strips - Google Patents

Abstract

Process for the continuous production of thick-walled insulating tubes from several thermoplastic foam strips, which are brought together and heated one after the other in the order of the insulating layers from the outside to the inside parallel to their longitudinal extension, preferably in the middle, within the width of the respective preceding foam strip, with a not yet heated foam strip in each case a heated foam strip is placed and the two foam strips are welded to form a narrow seam.

Description

50

The object of the invention relates to a process for the continuous production of thick-walled multilayer insulating pipes made of thermoplastic foam strips, the width of which depends on the respective Isolation tube diameter and the thickness of the foam strip is matched, with the foam strip in the order of the insulating layers from the outside to the inside parallel to their longitudinal extension one after the other are brought together, the later forming the insulating tube inside briefly to the thermoelastic or the thermoplastic state and then the foam strip transversely to its longitudinal extension is deformed to the pipe cross-section and connected along the side edges.

The invention also relates to a device for carrying out the method with a revolving belt for transporting the foam strips that run continuously over a pulley, each with a heating device assigned to a foam strip, a molding funnel with a cooled one Form tube and a welding device for closing the butt seam of the side edges.

Such a method and a device is known from DE-OS 26 54 879, for example

In the course of energy-saving measures, thicker and better insulation for heat-carrying lines, in particular hot water pipes, heating cables etc. required in the usual installation area If the pipe diameter to be insulated is predominantly smaller than 45 mm, the required insulation thickness corresponds approximately to a pipe diameter of 30 mm, that an insulation pipe made of foam with a thickness of 30 mm has an inner diameter of about 30 mm and an outer diameter of 90 mm Es it is very difficult to form an insulating tube with such small inner diameters from thick foam strips, without upsetting and wrinkling of the foam are avoided.

De 'invention is only based on the object Production of thick-walled insulating tubes in a continuous process with foam strips avoiding them from wrinkling and especially for smaller pipe diameters, such as those in installation insulation are common. The invention is based on thick-walled insulating tubes, which consist of several one above the other arranged foam strips are constructed.

Based on the method according to DE-OS 26 54 879, it is proposed according to the invention, in each case to place a not yet heated foam strip on a heated foam strip and weld the two foam strips together to form a narrow seam. Because of the engagement several foam strips for producing the thick-walled insulating tube is achieved that the continuous Manufacturing process can be done quickly because thin foam strips are essential can be heated faster than thick and thus the method for producing the insulating tube with short Heating times can be carried out. It is possible, according to the method according to the invention, for to process the insulating tubes of foam strips of different thicknesses together, in particular thinner layers can be chosen for the inner part of the insulating tube with the small diameters and thicker foam layers for the outer part of the insulating tube. In addition, foam strips can also be used different qualities are used, with more heat-resistant qualities being the inner layer of the insulating tube can form and, for example, weather-stable or more flame-resistant foam qualities the outside of the insulating tube. The inventive method also has the advantage that the heat of the already heated foam strips on the following, not yet heated foam strips transfers, but also on the underside, which as a result of the even heating of the Foam strip a kind of tempering, d. H. Stress-relieving occurs and the insulating tube formed later is very dimensionally stable and low in tension.

According to the method of the invention, the layers formed from the foam strips are first only connected by welding along a narrow seam, so that the foam strips slightly opposite each other when forming the insulating tube

which can be moved, which enables easy shaping and good adjustment the connection of the side edges of the insulating tube to the closed insulating tube then occurs at an opposite one Make another connection seam. The insulating tube is then used for assembly purposes slit open again at a point outside of the two connecting seams mentioned. Hisr also remains then a certain mobility of the individual insulating layers against each other, since they are in these areas are not connected to each other, which makes the assembly is facilitated.

In a further development of the method according to the invention it is provided that the foam strips during the heating along the side surfaces are cooled. This is an exact alignment of the foam strips possible, and at the same time the side edges are also protected from overheating; this applies in particular , for the protruding edges of the wider ones below Foam strips, which are also covered during the heating of the top foam strip be cooled with chilled guide rails on the top.

In an advantageous embodiment of the device according to the invention for carrying out the method are coolable and adjustable guide strips for the side surfaces or Side edges of the foam strips arranged and in the transport direction in front of the deflection and pressure roller a welding device for the narrow weld seam

This makes it possible to use a known device for carrying out the method, as is shown, for example, in FIG the German patent specification 25 32 406 is described, and also to supplement similar facilities economically, in order to continuously produce thick-walled insulating pipes from several foam strips.

The invention is explained in more detail in the drawing using an exemplary embodiment

It shows

F i g. 1 shows a schematic overall view of a device for producing insulating pipes from foam strips,

F i g. 2 shows an enlarged section in a schematic representation for the merging area the foam strip,

F i g. 3 the section AA according to FIG. 2,

F i g. 4 the section BB according to FIG. 2,

F i g. 5 the section CC according to FIG. 2,

F i g. 6 the view D according to FIG. 2,

F i g. 7 the assignment of the foam strips, FIG. 8th the formation of the insulating tube in cross section

F i g. 9 and FIG. 10 two insulating tube cross-sections,

F i g. 11 shows an insulating tube cross-section with a slide lock.

With the in F i g. 1 can be made of foam strips made of thermoplastic foam, for example polyolefin foams, such as crosslinked polyethylene foams, insulating tubes 22. Foam strips 2, 5 are applied here from a supply roll and a further supply roll, not shown, via deflection rollers 3 to an endlessly circulating conveyor belt 8. An adhesive point 4 can also be provided here for endless joining of the foam strips when changing rolls. First, the foam strip 5 runs through a heating device 9, for example an infrared heater, the top of the foam strip being heated up to the thermoelastic or thermoplastic area. The next foam strip 2 is then fed onto the top of the foam strip 5, the deflection roller 3 simultaneously taking on the task of the pressure roller. After passing through a second heating device 7, the foam strips run into a molding funnel 10 and are then guided through a molding tube 14 with cooling by means of rollers 16 with further cooling and drawn off, and at point 19, for example, by means of a welding device with a heating blade the butt seam is closed along the length of the edges of the insulating tube, and after passing through a pressing and pulling device 20, the insulating tube 22 leaves the system. A slitting device for slitting the insulating tube for the subsequent assembly and a winding device can also be arranged downstream here. In the area 19, instead of welding the insulating tube, a slide lock can be welded on along the two edges of the insulating tube.

In the F 'g. 2 is the design of the device for Schematically connecting several foam strips and producing thick-walled insulating pipes from them Depending on the thickness of the insulation tube, two, three or more foam strips can be used with a corresponding number of heating devices and supply devices to an insulating tube connected and shaped. In the example shown, there are only insulating tubes made of two foam strips 2.5 shown with two heating devices 7.9. From FIG. 7 it can be seen that the foam strips 5, 2 have different lengths according to their thickness and the insulating tube diameter, Preferably, the foam strips 2, 5 are brought together in the middle and in the middle area by means of a weld seam 1 stapled together. In the manufacturing direction, which is indicated by the arrow 24, according to FIG. 2 first of all the foam strips 5 when passing through the heating device 9, for example infrared radiators its upper side is heated to plasticity. The second, narrower foam strip 2 is then applied, the via a guide device 15, 17 and the deflection and pressure roller 3 on the foam strip 5 is applied. In the feed and connection area between deflection and pressure roller 3 and foam strips 5, the hot air device 6 is arranged whereby the two foam strips 2, 5 in small width to form the weld seam 11 are welded together. Then the two run Foam strips 5, 2 further into the second heating device 7, in which the surface of the foam strip 2 is heated up to the plastic state. Depending on the desired thickness of the insulating tube now a further feed of a further foam strip and a further heating device downstream until the foam strips have reached the desired thickness of the insulation be fed to the shaping.

For the production of the thick-walled insulating pipes from several foam strips, it is very important to that these are perfectly guided parallel to each other and in the desired position. For this reason it is provided that the foam strips fed to the heating device are already in the feed

area-oriented; this is, for example, as shown in FIG. 6 shown, the side Guidance through adjustable delimitation strips is provided as a guide device 15, 17. Even when walking through of the heating devices 7, 9, it is necessary to properly guide the foam strips. The F i g. 3 shows the cross section AA through the heating device 9, in which a foam strip has to be guided first. Here the orientation of the foam strip 5, as in 3 shown by means of guide strips 12, 13 along causes the longitudinal edges of the foam strip. These guide strips 12, 13 are cooled, for example with running cooling water, and are - what is not detailed - in width and height adjustable. is

The F i g. 5 shows the cross section CC through the heating device 7 with the guide for several foam strips. Here guide strips 18, 19a are also adjustable in height and width and with cooling designed so arranged that they cover laterally protruding edges 5a of the lower foam strip and thus protect against overheating. At the same time, they form the guide for the edges of the upper foam strip 2.

The F i g. 4 shows a schematic cross section according to section BB according to FIG. 2 in the area of the deflection and pressure roller 3. The merging of the foam strips 5 and 2 and the formation of the weld seam 11 is shown; The foam strips are continuously carried on by the conveyor belt 87. Preferably, the strips 2, 5 are aligned centrally one above the other, parallel to their longitudinal extent. This can be useful, for example, if the multilayer insulating tube to be produced is to be equipped with a slide lock, as exemplified in FIG. 11 shown in cross section Since a butt seam 20ö is not welded when a slide fastener 2i is provided, a more airtight seal is obtained if the butt seams 20a, 20b of the two layers 2, 5 are used as in FIG. 11 shown offset from one another so that a kinked butt joint is formed

In FIG. Fig. 8 is a schematic of the formation of each other Foam strips 5, 2 connected linearly along the weld seam 11 to the pipe cross-section Since the foam strips 2.5 can still be moved easily against each other, is a very slight deformation to the cross-section possible. Even for insulating pipes with very small inner diameters and large wall thicknesses, it is according to the invention Process possible to produce these without internal compression folds. Are preferred for the inner Layers of the insulating tube used thinner foam strips and for the outer thicker, such as shown in Fig. 10 In the event that the insulating tube with a weld 20c is closed in the longitudinal direction, the tube is subsequently slotted see slot 23, for the assembly enable. This slot can later be closed with a sticky tape, it can however, they can also be left open, since the insulating tube produced by the method is dimensionally stable and dimensionally true and the slot 23 is not open

F i g. 9 shows a variant of the shaped insulating tube 22. Insulating tubes of the type described have opposite single-layer insulating pipes have the advantage of greater flexibility when opening and are easy to handle.

In addition 5 sheets of drawings

Claims (4)

Patent claims: 1. Process for the continuous production of thick-walled multilayer insulating pipes from thermoplastic Foam strips, their width on the respective insulating tube diameter and the thickness of the foam strip is matched, the foam strips in the order of the insulating layers merged one after the other from the outside to the inside parallel to their longitudinal extent the side that will later form the inside of the insulating tube briefly extends into the thermoelastic resp. thermoplastic state and then the foam strip transversely to its longitudinal stretch is kung to the pipe cross-section ve * -formed and along the Side edges is connected, characterized in that in each case a not yet heated Foam strip is placed on a heated foam strip and the two Foam strips are welded to form a narrow seam. 2. The method according to claim 1, characterized in that the foam strips during the Heating along the side surfaces are cooled. 3. The method according to claim 1 or 2, characterized in that the protruding edges of the wider foam strips at the bottom while the top foam strip is being heated be cooled by covering with chilled guide strips on the top. 4. Device for carrying out the method according to one of claims 1 to 3 with a circulating belt for transporting the foam strips continuously running over a deflecting roller, a respective heating device assigned to a foam strip, a forming funnel with a cooled forming tube and a welding device for closing the butt seam of the side edges , characterized in that in the area of the heating devices (7, 9) coolable and adjustable guide strips (12, 13) for the side surfaces or side edges (5a, Sb) of the foam strips (2,5) are arranged and in the transport direction in front of the deflection and pressure roller (3) a welding device (6) for the narrow weld seam (11) is arranged.