EP1725351B1 - METHOD FOR PRODUCING A FLUID CONDUIT, IN PARTICULAR A FLUID CONDUIT IN A CO sb 2 /sb REFRIGERATING PLANT - Google Patents

Abstract

The invention relates to a method for producing a fluid conduit, in particular a fluid conduit for a CO2 refrigerating plant. The aim of said invention is to develop a quick and inexpensive method. For this purpose, several pipes (5-9) are simultaneously supplied by means of at least one roller (11) which is provided with peripheral grooves (14) and are helically wound in a parallel direction with respect to each other, wherein each pipe (5-9) is guided along a helical line and the helical lines of all pipes (5-9) are parallel to each other.

Description

The invention relates to a method for producing a fluid line, in particular a fluid line in a CO ₂ refrigeration system, according to the preamble of claim 1.

Such a procedure is from the document US-A-3646599 known.

In many technical installations, e.g. Refrigeration systems or hydraulic systems, a fluid is transported under high pressure and / or high temperatures. The lines used for this purpose are usually made of metallic materials and have relatively high wall thicknesses. If one wishes at the same time flexible lines, e.g. To meet requirements for vibration resistance, these cables are often wrapped around their longitudinal axis. However, such wound lines can be made only with a limited cross-section. If you want a larger flow rate, then split the line into several individual tubes. The individually produced wound tubes are subsequently pushed into each other. This method is relatively expensive and requires tight tolerances with respect to the pitch and diameter of the turns.

A refrigeration system usually consists of several components. These include a compressor, two heat exchangers and a valve. These components must be connected by cables. In particular, in mobile applications, such as refrigeration systems, which are used for cooling in motor vehicles, they must Pipes in addition to corrosion resistance and vibration resistance also have some flexibility. On the other hand, such a pipe, especially if CO ₂ (carbon dioxide) is used as a refrigerant, must have a considerable compressive strength. As a result, such a line is relatively expensive.

The invention has for its object to provide a fast and inexpensive method for producing a fluid line.

This object is achieved by the method according to claim 1.

With this configuration, you can use relatively thin pipes. The effective cross section of the fluid line then results from the sum of the cross sections of all pipelines. Pipelines with a comparatively thin cross section have inherently a relatively high compressive strength, ie the expense which one must exert for compressive strength can be kept to a minimum. Due to the helical arrangement of the individual pipes also gives a certain flexibility. The production is particularly cost-effective, that you wrap several pipes simultaneously and in parallel. As a result, you reach a virtual automatic one Arrangement of the pipes such that the pipes are adjacent or at a predetermined distance from each other. Subsequent mounting of individual pipelines into one another, or adjustment can be omitted. With the winding of the pipelines a large part of the manufacturing process is completed. The method is in principle suitable for the production of fluid lines, eg for hydraulic or refrigeration systems. However, the process is of particular importance for installations which operate with a refrigerant which is under a higher pressure, for example CO ₂ (carbon dioxide). It leads to the piping via at least one roller, which is provided with circumferential grooves. With this role, the desired lateral alignment of the pipes relative to each other can be ensured in a simple manner. If one uses several roles of the same kind, then you can achieve a relatively accurate positioning of the individual pipes relative to each other over the circumference of the individual turns of the helix. Once the pipes have been bent over an initial angle of, for example, 10 °, a guide with rollers is no longer essential, because the turns once formed no longer bend on its own.

In this case, it is preferred that the pipes are cut in succession after the turns have been produced, and that the bundle formed by the pipes is rotated by a predetermined angle between each cutting operation. This takes into account the fact that the individual pipes later, ie when the windings have been completed, all at about the same axial position of the "screw" should end. By a sequential cutting and twisting of the tube bundle it is achieved that the cutting process can always be done in the same place. This results in the correct length of the individual pipes almost automatically.
With this method, in principle, lines of any length and various lengths can be produced continuously. It is therefore ideal for mass production, but at the same time meets the requirements for a fast type conversion.

Preferably, after winding, the ends of the pipes are bent parallel to the axis of the helix. This makes it easier to mount a connection for the pipes. The subsequent assembly process is simplified.

Preferably, the line is embedded in a plastic, at least in the region of its helical turns. By "plastic" should also be understood here a rubber. The plastic stabilizes the "corpus" of the pipe, but at the same time ensures that the pipe has a certain flexibility. The plastic sheath not only produces mechanical stabilization. It also causes an increased thermal resistance to the environment, so that heat losses can be kept low. In addition, the embedding provides corrosion protection for the piping, especially when used in aggressive environments.

Preferably, before embedding, the ends of the conduit are twisted at a predetermined angle counter to the direction of winding, holding them in place in the twisted position and releasing them after embedding. For example, you can twist the ends by about 10 ° to each other. This results in small distances between adjacent turns in which the plastic can penetrate. The embedding with the plastic can be done for example in an injection molding process. The spaces between the individual windings filled by the plastic prevent the pipes from touching each other and causing them to chafe or rub against each other during the operation of the refrigeration system due to the vibrations that occur. Thus, unwanted noise is avoided, as well as a risk of possible leaks due to wear of the pipes at the points of contact is reduced. If you let go of the ends after injection molding (or other embedding), then the turns of the helix of all pipes are under a certain bias. This helps to improve the strength of the line.

In a preferred embodiment, it is provided that you keep a core inside the turns when embedding the line. The plastic is thus designed as a hollow cylinder. The hollow interior saves weight. By leaving the interior or core free, the flexibility of the conduit is improved. Finally, if desired, ancillary equipment, For example, electrical lines or the like, lead through the interior of the line.

Preferably, one provides associated ends with a common fitting. This facilitates subsequent assembly of the conduit in a technical facility, e.g. in a refrigeration system.

It is preferred that one connects the fitting with the plastic. This gives over the entire length of the line improved compressive strength. There are no positions where shear forces could act on the piping. Overall, this improves the strength of the line.

It is preferred that one presses the fitting against the plastic and welded to the plastic. This gives a very strong connection between the fitting and the plastic. The pipes get after releasing the contact pressure a small increased bias in the axial direction of the helix.

Preferably, the ends of the pipelines are passed through the connection piece and a supernatant forming thereby separates. This ensures that the pipes terminate flush with the end face of the fitting. The guidance of the refrigerant is then taken over exclusively by the pipelines, which are preferably formed from a suitable metal, for example aluminum. The plastic only has a supporting function.

It is preferred that one uses a laser for separating. The laser is able to separate the supernatants flush with the end face of the fitting.

Preferably, at least one deflection roller is provided, whose axis of rotation encloses an acute angle relative to the axis of the roller. The deflection roller causes a lateral deflection movement of the supplied pipes and thereby controls the slope of the helix.

In accordance with the Invention leads the pipes against a deflection surface, which includes with the feed direction a first angle in a feed plane and a second angle with the feed plane. The pipes are thus deflected twice, so that they bend on the one hand in the circumferential direction of the helix, on the other hand, but also receive an axial feed, so that the helix results.

Fig. 1

eine schematische Darstellung zur Erläuterung der Herstellung einer Fluidleitung,

Fig. 2

eine Anordnung von Rohrleitungen,

Fig. 3

die Darstellung nach Fig. 1 von oben,

Fig. 4

eine genutete Umlenkrolle,

Fig. 5

eine Leitung nach dem Herstellen der schraubenlinienförmigen Windungen,

Fig. 6

die Leitung nach Fig. 5 mit ausgerichteten Enden,

Fig. 7

ein Anschlußstück,

Fig. 8

eine zweite Ausbildungsform eines Anschlußstücks,

Fig. 9

eine Leitung mit Anschlußstücken und

Fig. 10

eine abgewandelte Ausführungsform einer Leitung in perspektivischer Darstellung.

The invention will be described below with reference to preferred embodiments in conjunction with the drawings. Herein show:

Fig. 1

a schematic representation for explaining the preparation of a fluid line,

Fig. 2

an arrangement of pipelines,

Fig. 3

the representation after Fig. 1 from above,

Fig. 4

a grooved guide pulley,

Fig. 5

a lead after making the helical turns,

Fig. 6

the line after Fig. 5 with aligned ends,

Fig. 7

a fitting,

Fig. 8

a second embodiment of a fitting,

Fig. 9

a line with fittings and

Fig. 10

a modified embodiment of a conduit in perspective view.

Fig. 9 shows a line 1 with two connecting pieces 2, 3 and a body 4, the production of which is to be explained below.

The body 4 is formed by five pipelines which are in Fig. 1 from the side, in Fig. 2 from the front and in Fig. 3 are shown from above. The wall thickness of these pipes 5-9 is in Fig. 2 shown exaggeratedly big. The wall thickness must be chosen to be high enough to withstand pressure generated in the hollow interior 10 of each conduit 5-9 when the conduit 5-9 is later used in a refrigeration system using CO ₂ (carbon dioxide) as the refrigerant is working. Such pressures can certainly reach a magnitude of several 100 bar. However, pipes 5-9 with a smaller cross-section are relatively more resistant to pressure than pipes with a larger cross-section but the same wall thickness. Of course, the line 1 thus produced is also applicable to other refrigerants, including those which operate at lower pressures.

Like from the Fig. 1 and 3 can be seen, the pipes 5-9 are guided in a plane next to each other over three pulleys 11-13. The pulleys 11-13 are the same. The guide roller 11 is in Fig. 4 shown enlarged. It has five circumferential grooves 14. The number of circumferential grooves, which are evenly distributed in the axial direction of the guide roller 11, of course, depends on the number of simultaneously to be wound pipes 5-9.

The two pulleys 11,12 are shown fixed here. The guide roller 13 is movable in the direction of a double arrow 15, ie perpendicular to the plane in which the pipes 5-9 are arranged during feeding.

Of course, the pulleys 11, 12 may be movable, if this should be necessary for an insertion.

The pipes 5-9 are fed in a feed direction 16. They can be handled by supply spools, not shown. Means by which the feed is generated are known per se and become therefore not shown in detail. For example, you can use this role pairs that act from opposite sides on the pipes 5-9 and cause by means of a frictional force driving on the pipes 5-9.

In the feed direction 16 behind the last deflection roller 13, a deflection surface 17 is arranged. This deflection 17 closes with her in Fig. 1 Direction component shown an angle not equal to 90 ° with the plane in which the pipes 5-9 are supplied. The deflection 17, more precisely the in Fig. 1 recognizable component causes, together with the last deflection roller 13, that the pipes 5-9 are bent annularly, so that in the in Fig. 1 represented view, so to speak, a circular shape of the bend results.

How out Fig. 3 can be seen, the deflection 17 includes, however, with the feed direction 16 an angle not equal to 90 °, so that the supplied pipes 5-9 are deflected not only on a circular path, but also receive a deflection perpendicular to the feed direction 16 during deflection. Accordingly, the pipes 5-9 are guided on a helix. The last guide roller 13 may have to support this deflection movement relative to the other two guide rollers 11, 12 has an axis of rotation, which is no longer aligned parallel to the axes of the guide rollers 11, 12, but with these forms an acute angle. Also, the guide roller 12 may be disposed at an acute angle to the guide roller 11 to the slope of the To control helix. The deflection surface 17 serves to adjust the slope with a relatively high accuracy.

As is clear from the FIGS. 3 and 5 results in the pipes 5-9 so wound helically, whereby even when winding the orientation of the pipes 5-9 is maintained parallel to each other. After winding, the pipes 5-9 are still at each other. The turns thus produced form a hollow cylinder.

The pipes 5-9 now have ends that project "obliquely" from the body 4. So they have a radial and an axial direction component. However, they are all at least substantially the same length. This is achieved by not severing the individual pipes 5-9 at once when the body 4 has reached its desired length, but sequentially. Thus, after reaching the predetermined length, first a pipeline, for example the pipeline 5, is disconnected, then the body 4 continues to rotate until the pipeline 6 reaches the position of the previously separated pipeline 5 and then separates the pipeline 6. This process is repeated, i. between the cutting of the individual pipes 5-9 is always a rotation through an angle corresponding to 360 ° by the number of pipes.

In a further production step, the ends 18-22 are now bent and parallel to the axis of the body. 4 aligned. Thereafter, it is possible to postpone the connector 3 to the ends 18-22. The connector 3 has for this purpose a number of holes 23, which corresponds to the number of pipes 5-9.

Fig. 7 shows a first embodiment of a fitting 3 with a circular shape. Fig. 8 shows a modified embodiment of a connecting piece 3 'with a hexagonal shape and in Fig. 8a as a side view and in Fig. 8b as a front view. The shape of the fitting 3, 3 'depends on the later desired use.

Before or after the sliding of the connector 3, the body 4 is still with a in Fig. 9 provided plastic 24 provided. The plastic 24 may also be natural rubber, which is introduced for this purpose in a vulcanized form. The production of the plastic is advantageously carried out by injection molding. The body 4 is introduced for this purpose in an injection mold. Before the introduction, however, the ends of the body 4 are rotated against each other against the winding direction. This should be represented by the arrows 25, 26. The angle of rotation is relatively small. It is for example 10 °. By this measure, there is a small distance between adjacent turns of the body 4, in which then during injection of the plastic 24 of the plastic can occur. By a core ensures that the hollow interior of the body 4 is not completely filled by the plastic 24, but a hollow cylinder remains. After spraying the plastic 24, the tension with which the ends of the body 4 against each other twisted or "wound up", loosened again, so that the wound pipes 5-9 remain in the plastic 24 with a certain bias.

After the body 4 has been embedded in the plastic 24, the two connecting pieces 2, 3 are pressed under pressure against the plastic 24. This is indicated by arrows 27, 28. Of course, the corresponding forces are directed so that the connecting pieces 2, 3 abut the entire surface of the end face of the plastic 24. Thereafter, the connecting pieces 2, 3 are welded or glued to the plastic 24, so that overall results in a quasi-monolithic block in which a flow path for the carbon dioxide refrigerant is formed in the interior of the helically curved pipes 5-9.

The ends 18-22 of the pipes 5-9 are so long that they, as shown in the connector 3, can be passed through the connector 3 and protrude with a small projection from the connector 3. This supernatant is separated by means of a laser cutter 29. This ensures that you can make the ends 18-22 flush with the end face of the connector 3.

The production of the line 1 has been described so far with five pipes 5-9. Out Fig. 10 a modified embodiment of a pipe 1 can be seen, in which a total of ten pipes are helically wound to connect between two terminals 2, 3 to create. The cavity which forms inside the body 4 is represented by a circular cylinder 30.

Claims (12)

1. Method of manufacturing a fluid pipe, particularly a fluid conduit in a CO₂ refrigeration system, in which several pipes (5-9) are simultaneously supplied via at least one roller (11), which is provided with circumferential grooves (14), the pipes (5-9) being wound in parallel to each other in a helical line shape, each pipe (5-9) being guided along a helical line and the helical lines of all pipes (5-9) extending in parallel to each other, characterised in that the pipes (5-9) are guided towards a deflection face (17), the deflection face (17) enclosing a first angle with the supply direction (16) in a supply plane, and a second angle with the supply plane.
2. Method according to claim 1, characterised in that after making the windings, the pipes (5-9) are cut to length one by one, the bundle (4) formed by the pipes (5-9) being twisted by a predetermined angle between the individual cutting processes.
3. Method according to claim 1 or 2, characterised in that after winding the ends (18-22) of the pipes (5-9) are bent over in parallel to the axis of the helical line.
4. Method according to one of the claims 1 to 3, characterised in that at least the helically shaped winding area of the conduit (1) is embedded in a plastic material (24).
5. Method according to claim 4, characterised in that, before the embedding, the ends (18-22) of the conduit (1) are twisted by a predetermined angle in relation to each other against the winding direction, are held in the twisted position during the embedding and are released after the embedding.
6. Method according to claim 4 or 5, characterised in that during embedding of the conduit a core within the windings is kept free.
7. Method according to one of the claims 4 to 6, characterised in that ends (18-22) belonging together are provided with a common connecting piece (2, 3).
8. Method according to claim 7, characterised in that the connecting piece (2, 3) is connected to the plastic material (24).
9. Method according to claim 8, characterised in that the connecting piece (2, 3) is pressed against and welded onto the plastic material (24).
10. Method according to one of the claims 7 to 9, characterised in that the ends (18-22) of the pipes are guided through the connecting piece (2, 3) and an occurring excess length is cut off.
11. Method according to claim 10, characterised in that the cutting is made by means of laser (29).
12. Method according to one of the claims 1 to 11, characterised in that at least one guide roller (13) is provided, whose rotational axis encloses an acute angle in relation to the axis of the roller (11).

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