PRODUCTION OF A PIPE WITH A FUNCTIONAL LAYER ON A CORE AND A PIPE

Abstract

For producing a pipe, a core is provided and a functional material, a fiber composite material and a shrink material forming a shrink tube are applied radially externally to the core. The pipe is thermoformed by heating of the pipe with application of radially inward pressure to the fiber composite material and radially outward pressure to the functional material, this in turn by radially inward thermal contraction of the shrink tube and/or radially outward thermal expansion of the core. At the same time consolidation of the functional material together with the fiber composite material form the pipe, and cooling to a cold temperature and demolding of the consolidated pipe from the shrink tube and from the core. The functional material has such a media resistance with respect to the medium that for a planned usage period it is less damaged by the medium than the fiber composite material.

Claims

1. A process for producing a pipe extending along a central longitudinal axis and having a tubular main body composed of a fiber composite material and the tubular main body having an inside firmly connected to a tubular functional layer composed of a functional material and the tubular function layer having an inner wall surrounding an interior of the pipe, the pipe in a fabricated state being intended to accommodate a defined medium in the interior, which comprises the steps of: providing a core extending along the central longitudinal axis and having an outer wall forming a bearing face for the inner wall of the tubular functional layer; applying the functional material radially externally to the core; applying the fiber composite material radially externally to the functional material; applying a shrink material, which at least in a course of the process forms a shrink tube, radially externally to the fiber composite material; thermoforming the pipe by: heating the core, the functional material, the fiber composite material and the shrink material to a hot temperature; at a same time, applying pressure radially against one another by a radially inward pressure to the fiber composite material and a radially outward pressure to the functional material: by radially inward thermal contraction of the shrink tube; and/or by radially outward thermal expansion of the core; at a same time, consolidating the functional material together with the fiber composite material to define a consolidated pipe with the functional layer and the tubular main body; cooling the consolidated pipe to a cold temperature and demolding the consolidated pipe from the shrink tube and from the core; and selecting the functional material such that at least in the fabricated state the consolidated pipe has such media resistance with respect to a medium that at least for a planned usage period the consolidated pipe is less damaged by the medium than the fiber composite material if the fiber composite material were to be equally exposed to the medium.

2. The process according to claim 1, wherein on radially external application to the core, the functional material is already in a form of a completed functional tube.

3. The process according to claim 1, which further comprises applying the functional material radially externally to the core by being wound onto the core.

4. The process according to claim 1, which further comprises applying the fiber composite material radially externally to the functional material by being laminated over and/or wound round.

5. The process according to claim 1, which further comprises applying the shrink material radially externally to the fiber composite material by being wound round.

6. The process according to claim 1, wherein the core has an outer wall, the core in relation to the outer wall has a greater radial thermal contraction between hot temperature and the cold temperature than the consolidated pipe.

7. The process according to claim 1, wherein during a production of the pipe: introducing a metal layer as part of the tubular functional layer into the pipe; and/or before, during or after production, metallizing the tubular functional layer to form the metal layer.

8. A pipe, comprising: a tubular main body extending along a central longitudinal axis, composed of a fiber composite material, and having an inside wall; and a tubular functional layer composed of a functional material and having an inner wall, said inner wall of said tubular functional layer surrounding and defining an interior of the pipe, the pipe being intended to accommodate a defined medium in said interior, said tubular functional layer is firmly connected to said inside wall of said tubular main body, wherein said functional material is consolidated together with said fiber composite material to form the pipe, wherein said functional material is selected such that at least in a fabricated state said functional material has such media resistance with respect to the defined medium that at least for a planned usage period said functional material is less damaged by the defined medium than said fiber composite material if said fiber composite material were to be equally exposed to the defined medium.

9. The pipe according to claim 8, wherein the pipe which in operation carries the defined medium in a form of coolant in a cooling circuit of a fuel cell or the defined medium in a form of hydrogen of the fuel cell.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0047] FIG. 1 is an exploded, cross-sectional view of a pipe during its production with a core and a shrink tube;

[0048] FIG. 2 is a perspective view of a provision of the core in the production process;

[0049] FIG. 3 is a perspective view of an application of the functional material, metal layer and fiber composite material;

[0050] FIG. 4 is a perspective view of the application of a shrink material and the fabrication of the pipe in an oven in a schematic sectional representation;

[0051] FIG. 5 is a perspective view of the pipes taken out of the oven, with the core and the shrink tube;

[0052] FIG. 6 is a perspective view showing a demolding of the pipe from the core; and

[0053] FIG. 7 is a perspective view showing metallization of the pipe, completed to this point.

DETAILED DESCRIPTION OF THE INVENTION

[0054] Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a pipe 2 of the invention during its production in an exploded representation in cross-section. The pipe 2 extends along a central longitudinal axis 4 in the form of a straight line. In FIG. 1, the central longitudinal axis 4 is perpendicular to the plane of the page. The pipe 2 radially internally (reference always to the central longitudinal axis 4) contains a tubular functional layer 6 composed of functional material 8. Radially outwardly, the functional layer 6 is surrounded by a tubular main body 10 composed of a fiber composite material 12. The latter material is indicated presently in the form of two concentric plies of prepregs (in actual fact they are implemented as overlapping one another with one or more plies), which are laminated over or wound around the functional layer 6. At its inside 14, the main body 10 is connected firmly to an outside 16 of the functional layer 6.

[0055] FIG. 1 shows the pipe 2 while a process for its production is being implemented. Accordingly, the arrangement composed of the functional layer 6 and the main body 10 is applied on a radially internal core 18, which likewise extends along the central longitudinal axis 4. The core is fabricated from a sleeve 30 composed of plastic with a metal reinforcement 32 in the interior for improving the dimensional stability.

[0056] The overall arrangement composed of the core 18, the functional layer 6 and the main body 10 is surrounded radially externally by a shrink tube 20.

[0057] The pipe 2 or the functional layer 6 radially internally has an inner wall 22, with which the pipe 2 surrounds an interior 24 within the pipe 2. The pipe 2 is equipped/intended, after fabrication, i.e. when in its fabrication state FZ in its operation B, to accommodate and carry a medium 26 in its interior 24. The operation B and fabrication state FZ and also the medium 26 are to be understood as indicated only symbolically in FIG. 1; in operation B and fabrication state FZ, the core 18 and the shrink tube 20 are then removed.

[0058] In the example, all of the structuresthe core 18, the functional layer 6, the main body 10 and the shrink tube 20are circular cylinders/sheaths.

[0059] Described below is a process for producing the pipe 2.

[0060] FIG. 2 in this regard shows how first the core 18 is provided. It again depicts the metallic inner core in the form of the reinforcement 32 and the outer core 30 applied radially externally to this inner core 32, in the form of the sleeve 30 composed of plastic. An outer wall 34 of the core 18 forms a bearing face for the inner wall 22 of the pipe 2 and hence for the functional layer 6 and the functional material 8.

[0061] FIG. 3 shows, in the next step, the application of the functional material radially externally to the core 18 or to its outer wall 34. In this case, the functional material 8 is wound onto the core 18, as a comparatively wide (therefore more of a cloth material) tape material 36. This takes place manually by an individual not further elucidated, who is indicated by way of their hands.

[0062] As soon as the functional material 8 has been wound completely onto the core 18, the fiber composite material 12here also in the form of cloth or tape material 36is applied in the same way to the functional material 8. This takes place in the same way as just explained for the functional material 8 and is therefore indicated in dashed form in FIG. 3.

[0063] FIG. 3 also shows in dashed form an alternative for the application of the functional material 8 to the core 18, when the latter, indeed, is not wound as tape material 36 but is instead pulled on/applied to the core 18, in the direction of the arrow 62, as a pre-prepared functional tube 60.

[0064] FIG. 3 shows in dashed form how optionally a metal layer 70 is introduced into the pipe 2 during the production of the latter, specifically by the metal layer 70 being wound as tape material 36 likewise onto the core 18 or functional layer 6 or functional material 8 in an intermediate step between application of the functional material 8 and of the fiber composite material 12.

[0065] FIG. 4 shows how subsequently a shrink material 40 is radially externally applied to the fiber composite material 12 (and therefore, lying beneath, to functional material 8 and core 18). This too takes place by wrapping, in this case with a comparatively narrow and therefore less cloth-like shrink tape 42. The result of this, after complete application, is the shrink tube 20 composed of the shrink material 40, which surrounds the fiber composite material 12. The componentscore 18, functional material 8, fiber composite material 12 and shrink material 40together form a pipe arrangement 46. For the purpose of wrapping, a winding device is indicated, though not further elucidated in the figure, and the pipe arrangement is mounted in rotation in this device.

[0066] In a further step, indicated only symbolically in FIG. 4, the pipe arrangement 46 is heated to a hot temperature WT in this case in an oven 50. In the oven 50 or by means of the oven 50, then, heating to the hot temperature WT takes place. Taking place accordingly is the actual thermoforming of the pipe 2 composed of functional material 8 and fiber composite material 12 of the pipe arrangement 46. In this procedure there is radial application of pressure by functional material 8 and fiber composite material 12 against one another.

[0067] This is accomplishedindicated in FIG. 1first by radially outward pressure 52 to the functional material 8 by radially outward thermal expansion of the core 18, indicated by arrows. And, secondly, by radially inward pressure 54 to the fiber composite material 12 by radially inward thermal contraction of the shrink tube 20, indicated by arrows.

[0068] The corresponding pressure and also the heat of the hot temperature WT in accordance with FIG. 4 lead to consolidation of the functional material 8 together with the fiber composite material 12 to give the pipe 2, containing the main body 10 and the functional layer 6 connected to it.

[0069] FIG. 5 shows two pipe arrangements 46 after withdrawal from the oven 50 and therefore containing completed pipes 2 on cores 18, surrounded by shrink tubes 20. The pipe arrangements 46 are then cooled down to a cold temperature KT. Also indicated are hangers 48, which serve to allow the pipe arrangements 46 to be suspended in the oven and for cooling.

[0070] The functional material 8 is selected such thatat least in the fabrication state FZ, i.e. when it has formed the functional layer 6it has such media resistance with respect to the medium 26 indicated in FIG. 1 that it is less damaged by the medium 26, at least for a planned usage period ED, than the fiber composite material 12 or the main body 10 would theoretically or hypothetically be damaged if it were equally exposed to the medium 26. The different extents of damage are represented symbolically in FIG. 1 by different-sized arrows 56 (comparatively little damage to functional layer 6) and 58 (comparatively high level of notional damage to main body 10).

[0071] FIG. 6 shows the following: provided as core 18 in FIG. 2 is a core which in terms of its outer wall 34 or its diameter, has a greater radial thermal contraction between hot temperature WT and cold temperature KT than the pipe 2 or its internal diameter at the inner wall 22. As a result of this, the core 18 can be easily pulled out of the fabricated pipe 2, in the direction of the arrow 64 from the pipe 2.

[0072] FIG. 7, finally, as an alternative to FIG. 3, shows in symbolically indicated form how, after the production of the pipe 2 fabricated to this point, the metal layer 70 is introduced, by the functional layer 6 being metallizedthat is, coated metallically. Here, strictly speaking, the metal layer 70, which is understood here as part of the functional layer 6, forms the inner wall 22 of the pipe 2.

[0073] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0074] 2 pipe [0075] 4 central longitudinal axis [0076] 6 functional layer [0077] 8 functional material [0078] 10 main body [0079] 12 fiber composite material [0080] 14 inside (main body) [0081] 16 outside (functional layer) [0082] 18 core [0083] 20 shrink tube [0084] 22 inner wall (pipe) [0085] 24 interior (pipe) [0086] 26 medium [0087] 30 sleeve [0088] 32 reinforcement [0089] 34 outer wall (core) [0090] 36 tape material [0091] 40 shrink material [0092] 42 shrink tape [0093] 46 pipe arrangement [0094] 48 hanger [0095] 50 oven [0096] 52 pressure (radially outward, core) [0097] 54 pressure (radially inward, shrink tube) [0098] 56 arrow (damage to functional layer) [0099] 58 arrow (notional damage to main body) [0100] 60 functional tube [0101] 62 arrow (application of functional tube) [0102] 64 arrow (extract of core) [0103] 70 metal layer [0104] B operation [0105] FZ fabrication state [0106] WT hot temperature [0107] KT cold temperature [0108] ED usage period