DE19638715C2 - Process for welding plastic pipelines together and mat-like heat exchangers produced by the process for cooling and / or heating purposes - Google Patents

Description

The present invention relates to a method for together welding of plastic pipelines. Further concerns the Invention a mat-like manufactured by the method Heat exchanger for cooling and / or heating purposes, consisting of a Plurality of heat exchange lines from a cooling or Heating medium can be flowed through, which heat exchange lines each because are connected to a supply or return distribution line.

Such heat exchangers are used in particular for cooling rooms instead of conventional air conditioning systems. Man speaks of chilled ceilings in that a so-called. Mat is attached by water-carrying plastic tubes. The cooling water is due to the large number of plastic tubes spread over a large area. This mat can be invisible, for example under ceiling elements. This Heat exchange mats are also used for heating purposes settable.

In the manufacture of such heat exchangers, the many  almost parallel, flexible art fabric tubes with approx. 2 mm inner diameter, each on their one end with a flow distribution pipe and at the other Connect the end with a return distribution line.

According to a known manufacturing process, the connection between the plastic tubes and the flow or return Distribution line manufactured as follows: After the tubes have been summarized in their final arrangement, the respective Sprayed on distribution line. The main disadvantage of this The process lies in the fact that the necessary injection unit can hardly be bigger than 30-50 cm, otherwise un relatively high costs arise. That means that on only small mats can be produced in this way. Become bigger Mats required, then several small mats have to correspond large mat to be welded together.

The second manufacturing option is welding Plastic tubes to the distribution lines. This is one Tube inner diameter of only 2 mm is not without problems feasible, since the small tube cross-section in the loading rich in welded joints due to the melting plastic inevitably diminished, if not clogged at all. One of the Art manufactured heat exchanger is in its function be restricted and, in the worst case, can be completely unusable his.

In order to counter this disadvantage, a method of manufacturing has been developed  development of mats made of plastic tubes proposed first extruded the distribution line and into the still soft Plastic openings for connecting the tubes become. The plastic tubes are then placed in these openings introduced, whereby a fusion of the Tube ends with the distribution line. To sweat clogging or deforming the tube ends prevent, a movable plunger is in during the procedure the manifold is inserted which has a plurality of thorns on it points, which determined to intervene in the tube ends are. It goes without saying that the insertion of the push sels and pushing the thorns in and out of the tubes ends relatively cumbersome and for continuous production the heat exchanger mat is unfavorable.

EP 0 140 069 A2 describes a method for the tight connection of Pipe ends known in tube sheets. But there won't be two here Pipelines connected to each other. Rather, it will End of a pipe inserted into a hole in the tube sheet and connected to the hole wall. For secure anchoring in the The bottom of the tube becomes the tube end from the other side of the tube welded by means of a conical sonotrode. The resulting material displacement forms on the free Tube bulge a bead surrounding the hole. This bead is not a problem in a tube sheet and can if necessary, also be ground away. Such a process is for welding two plastic tubes together not suitable for the reasons described above. And you would  could somehow accomplish this, then the would Welding material expulsion in a harmful way pressed the cross section of the second plastic tube. The pro At best, blem would be shifted from one tube to the other been.

The formation of gutters serving as welding ridge storage, such as this from DE 42 44 017 A1 when welding size together Ren, thick-walled plastic parts is known, can not to be connected here, thin-walled plastic tubes be considered.

The present invention therefore has as its object Process for welding plastic pipelines specify, in particular in the small plastic tube Diameter to a distribution line provided with openings can be welded on without a cross-sectional vere or blockage can occur and without Welding process tools into the interior of the distribution line are pushing.

The method according to the invention corresponds to Features of claim 1. A ago by this method provided, mat-like heat exchanger for cooling and / or heating purpose corresponds to the features of the patent Proverbs 15

Exemplary embodiments of the  Subject of the invention described in more detail.

Fig. 1 shows a first variant of the connection heat exchange line / distribution line of a mat-like heat exchanger;

Fig. 2 shows a second variant of the same connection point;

Fig. 3 shows a third variant of the same connection point;

Fig. 4 shows a view of the mat-like Wärmetau clipper.

The method for producing a plastic pipe connection is explained using one of the connection points of a mat-like heat exchanger for cooling and / or heating purposes. This consists of a plurality of heat exchange lines 1 , of which one end 2 can be seen in each case to be connected to a distribution line, ie a forward or return line. For the sake of simplicity, only one wall of the distribution line 3 can be seen, in which an opening 4 is already present. The heat exchange line 1 should be connected to the distribution line 3 such that the cooling or heating medium, for. B. water, can flow freely through the opening 4 from the distribution line 3 in the heat exchange Lei device 1 or vice versa.

The most important part of the connection point is a connec tion element 5th It is a sleeve provided with an annular flange-like formation 6 which is to be connected to the end 2 of the heat exchange line 1 . The purpose of the ring flange-like formation 6 is not primarily to create a larger contact surface or contact surface between the end 2 of the heat exchange line 1 and the wall of the distribution line 3 . Rather, it is a matter of creating a region of the pipe cross section 7 of the heat exchange line end 2 , or of the connecting element 5 which extends this end, and the part line opening 4 surrounding annular recess 8 . This is formed by an annular web 9 , which surrounds the said pipe cross-section or opening area coaxially with from stood. This recess 8 is used to collect the molten pool produced when the plastic parts are welded together, ie the material expulsion of melting plastic. The material expulsion takes place in the connection area between the end face 10 of the annular web 9 and the corresponding counter surface 11 of the outer wall of the distribution line 3 when the two parts are joined or welded together according to arrow 12 .

As has been shown in practical tests, surprisingly even the vibration welding technique can be used due to the above-described formation of the connection area or the joining surfaces. Vibration welding is based on the principle of frictional heating of the joining surfaces. The parts are moved against each other under a certain pressure and vibration path. Vibration welding is a very economical method, but it is usually only suitable for welding larger areas with large casting tolerances, where a large amount of material is not important. A welding of the heat exchange line end 2 , i.e. a tube end with a 2 mm internal cross section, to the distribution line opening 4 would therefore normally be completely impossible with the vibration welding, since the small tube cross section would inevitably be welded due to the resulting material expulsion. In the connecting element 5 according to the invention, however, the material expulsion melts safely and easily in the annular recess 8 provided there . A further expansion of the material expulsion in the direction of the cross-sectional opening to be kept free, as has been shown, does not take place.

As for the connection between the heat exchange line end 2 and the connecting element 5 , there are various possibilities. Two examples are ersicht Lich from Figs. 1 and 2. The parts are not shown in the fully welded position, but rather in the term of assembly.

According to the first variant according to FIG. 1, the heat exchange line 1 is welded to the inner wall 13 of the sleeve-like part of the connecting element 5 . For this purpose, a welding edge 14 is formed on this inner wall 13 . The welding edge 14 is a cross-sectional taper of the inner cross-section of the connecting element 5 , this cross-section is reduced from a measure which enables the short insertion of the heat exchange line 1 to an approximately the inner cross-section of the heat exchange line 1 corresponding mass. For welding, the end 2 of the heat exchange line 1 is pressed against the welding edge and welded in this position. So that no air pockets can occur here, the welding edge 14 is not designed as a step but as a bevel. After the welding, as indicated by dashed lines, there is an approximately even transition from the inner wall of the heat exchange line 1 to the inner wall 13 of the connecting element 5 .

The situation is different in the variant according to FIG. 2. Here, the end 2 of the heat exchange line 1 is pushed into the connecting element 5 until it projects beyond its other end, ie the flange-like area. The inner wall of the connecting element 5 is thus completely covered by the heat exchange line 1, which fits just inside. As indicated by dashed lines, the end 2 of the heat exchange line 1 is expanded and flanged into the area of the annular recess 8 for welding. Of course, the recess 8 is dimensioned so large that it can then still perform its previously described function of collecting the melt pool. On the inner wall of the connecting element 5 , a weld-like cross-sectional widening 15 can be seen , however, in the opposite direction to the variant according to FIG. 1.

In both variants described, the welding between the heat exchange line end 2 and the Verbindungsele element 5 is preferably carried out by ultrasonic welding. With ultrasonic welding, ultrasonic vibrations are converted into extremely fast mechanical vibrations. The resulting high temperatures melt the plastic material and enable a high-quality welded joint. A sonotrode which can be inserted into the tube cross section 7 of the heat exchange line end 2 is used for the welding process. In particular in the variant according to FIG. 2, the sonotrode is preferably approximately designed as a stepped cylinder. It has a first part that can be inserted into the pipe cross section 7 and is adapted to this inner cross section, while a second part covers the flanged end 2 of the heat exchange line 1 and therefore has approximately the inner cross section of the recess 8 delimited by the annular web 9 .

The third variant according to FIG. 3 corresponds to that according to FIG. 2 as far as the connection of heat exchange line / connecting element is concerned . The difference lies in the annular recess serving to catch the melt pool. The recess 16 is here not formed on the connecting element 5 , but on the wall of the distribution line 3 . This can either by a shaped as a lowering wall thickness reduction or, as is shown, by forming an annular web 17 gene gene, which surrounds the opening 4 at a distance coaxially.

It should be mentioned here, finally, that it would also be possible in the context of the invention to inject 5 on the heat-exchange line end 2 the connecting element.

The method according to the invention for producing a plastic pipe connection, here between a heat exchange line 1 and the distribution line 3 , essentially comprises the following steps:

• - In the wall of the distribution line 3 , an opening 4 is introduced, for. B. by drilling.
• - A connecting element 5 is produced with a ring-shaped formation 6 . Note: The connecting element 5 can either be formed directly on the heat exchange line 1 , molded on this or first manufactured as a separate part.
• - Either in the region of the annular flange-shaped formation 6 of the connecting element 5 or in the opening 4 surrounding the area of the wall of the distribution line 3 , an annular recess 8 or 16 is formed.
• - If the connecting element 5 was produced as a separate part, the cut end 2 of the heat exchange line 1 and the connecting element 5 are connected to one another, preferably by ultrasonic welding.
• - The connecting element 5 and the distribution line 3 are welded together, preferably by vibration welding, with the material expulsion being generated being caught in the annular recess 8 or 16 .

This process creates a continuous, automated Allows production of plastic pipe connections. In particular special can be mat-like heat exchangers that have a variety of Have heat exchange lines, each with a preliminary or Return distribution line are to be connected in a considerable Working speed and in excellent quality in series production become.

In the mat-like heat exchanger according to Fig. 4, can be seen lines heat exchanger 1 comprises a plurality of U-shaped, both ends of which 2 are each connected by means of connecting elements 5 with a distribution line. 3 In this example, before run and return are combined in a double chamber tube, so that only one distribution line 3 can be seen in the drawing. Of course, two separately arranged supply and return lines are also conceivable, which run on two opposite sides of the mat-like heat exchanger.

In terms of production technology, it is in any case advantageous if the distribution line 3 is formed with a rectangular cross section, so that the connection elements 5 can be welded to a flat surface. But it is also possible, with a correspondingly curved design of the contact surface of the connec tion elements 5 , to be welded to a distribution line 3 with a circular cross section. The bend of the contact surface, ie the ring flange-like formation 6 , must correspond to the radius of the bend of the pipe surface of the distribution line 3 .

Claims (16)

Gen 1. A method for welding together plastic Rohrleitun, characterized in that the end (2) is provided at least one connecting element of two lines to be connected (1) with a Sal (5) which Verbindungsele element (5) in the connecting region to the second Line ( 3 ) has a pipe cross-section widened with respect to the pipe cross-section ( 7 ) of the first line ( 1 ), the cross-section widening of the material expulsion occurring when the plastic pipe lines ( 1 , 3 ) are welded together by the connecting element ( 5 ) to melt the plastic is caught. 2. The method according to claim 1, characterized in that the end ( 2 ) at least one line ( 1 ) with a connec tion element ( 5 ) is provided, which forms this end ( 2 ) flange-like, with on the end face ( 10 ) of this formation or on the corresponding counter surface ( 11 ) a recess ( 8 , 16 ) expanding the inner cross section is formed. 3. The method according to claim 2, characterized in that for welding one of a first line ( 3 ) branch off the second line ( 1 ), an opening ( 4 ) is made in the first line ( 3 ) and that in the area of this opening ( 4 ) end ( 2 ) of the second line ( 1 ) to be welded on is provided with a connecting element ( 5 ) which expands it end ( 2 ) in a flange-like manner, with an approximately annular recess ( 8 ) on the end face ( 10 ) of this expansion. is formed, which recess ( 8 ) during the welding process coaxially around the opening ( 4 ) of the first Lei device ( 3 ). 4. The method according to claim 2, characterized in that for welding one of a first line ( 3 ) branch off the second line ( 1 ), an opening ( 4 ) is made in the first line ( 3 ) and that in the area of this opening ( 4 ) the end ( 2 ) of the second line ( 1 ) to be welded on is provided with a connecting element ( 5 ) which expands this end ( 2 ) in a flange-like manner, on the surface ( 11 ) or wall of the opening ( 4 ) surrounding the opening first line ( 1 ), an approximately annular recess ( 16 ) is formed, for example by shaping an annular web ( 17 ) which gives the opening ( 4 ) at a distance coaxially around. 5. The method according to claim 3, characterized in that the recess ( 8 ) on the end face ( 10 ) of an approximately ring flange-like shape ( 6 ) of the connecting element ( 5 ) is formed such that the area of the pipe cross section ( 7 ) of the end ( 2 ) of the second line ( 1 ), or of this end ( 2 ) extending connecting elements ( 5 ), ring-shaped surrounding pipe cross-section expansion, which is formed by an annular web ( 9 ) which forms the opening area of the pipe cross-section coaxially surrounds at a distance. 6. The method according to claim 3, characterized in that the flange-like expansion of the connecting element ( 5 ) is formed so curved that it can be applied to the surface of a line ( 3 ) with, for example, a circular cross-section, the curvature of the flange-like expansion Radius of curvature of the pipe surface of the line 3 is selected accordingly. 7. The method according to any one of claims 1-6, characterized in that the connecting element ( 5 ) in the region of the end ( 2 ) of the line ( 1 ) is welded, for example by ultrasonic welding. 8. The method according to any one of claims 1-6, characterized in that the connecting element ( 5 ) in the region of the end ( 2 ) of the line ( 1 ) is injection molded. 9. The method according to any one of claims 1-8, characterized in that the connection between the region of the cross-sectional expansion of a connecting element ( 5 ) fastened at the end ( 2 ) of a first line ( 1 ) and the other line ( 3 ) Vibration welding takes place. 10. The method according to any one of claims 1-9, characterized in that the connecting element ( 5 ) to be fastened at the end ( 2 ) of a line ( 1 ) is at least partially sleeve-like, the sleeve-like part of the connecting element ( 5 ) can be pushed over the line end ( 2 ) and fastened there. 11. The method according to claim 10, characterized in that on the inner wall ( 13 ) of the sleeve-like part of the connecting element ( 5 ), a welding edge ( 14 ), ie a cross-sectional taper of the inner cross section of the connecting element ( 5 ) is formed to the To facilitate welding of the line end ( 2 ) in the connecting element, this cross section preferably being reduced from a dimension which enables the cable ( 1 ) to be pushed in tightly to a dimension corresponding approximately to the inner cross section of this line ( 1 ). 12. The method according to claim 11, characterized in that the welding edge ( 14 ) is formed as a bevel. 13. The method according to claim 10, characterized in that the end ( 2 ) of the line ( 1 ) is pushed so far into the connecting element ( 5 ) until it te on its other side, which is the second line ( 3 ) to be turned , protrudes, and for welding the line end ( 2 ) is flanged into the area of an annular recess ( 8 ) which enlarges the internal cross section ( 7 ) of the connecting element ( 5 ) on this side, the recess ( 8 ) is dimensioned such that, in addition to the flanged cable end ( 2 ), it can also absorb the material expulsion that occurs when the connecting element ( 5 ) is welded together with the other line ( 3 ). 14. The method according to claim 13, characterized in that on the inner wall of the connecting element ( 5 ) in the area in front of the annular recess ( 8 ) arranged, welded edge-like cross-sectional widening ( 15 ) is provided, ie that the cross section only by this cross-sectional widening ( 15 ) is enlarged and then again around the annular recess ( 8 ). 15. mat-type heat exchanger for cooling and / or heating purposes, produced according to claim 1, consisting of a plurality of heat exchange lines ( 1 ) through which a cooling or heating medium can flow, which heat exchange lines ( 1 ) each with a pre or Rücklaufverteilleitung (3) are connected, characterized in that the end (2) (1) is at least one of two pipes to be connected is provided with a connecting element (5) which Verbin-making element (5) in the connecting region to the second line (3 ) Compared to the pipe cross-section ( 7 ) of the first line ( 1 ) has expanded pipe cross-section, wherein in this cross-section widening formed by the connecting element ( 5 ) of the plastic pipes ( 1 , 3 ) resulting from the material expulsion of melting plastic is caught. 16. Mat-like heat exchanger according to claim 15, characterized in that a supply / return distribution line unit ( 3 ) is provided, for example in the form of a two-chamber hollow profile, in which the supply line and the return line are combined, the heat exchange Lines ( 1 ) are each bent approximately into a U-shape and are connected with their two ends ( 2 ) to the supply / return distribution line unit ( 3 ) in such a way that one end ( 2 ) to the supply line and the other end ( 2 ) is led to the return line.