DE29502262U1 - Multi-layer - multi-channel plastic pipe - Google Patents

Description

Deutsche Tecalemit GmbH

TECALAN

Karl-Oldewurtel-Strasse

33659 Bielefeld

PO Box 120128

33651 Bielefeld

Germany

Phone: 0049 521 4049 Fax: 0049 521 4049

Bielefeld, 04.02.95 Dr. Hu/ck-9512-5dfk

Multilayer - multi-channel plastic pipe

The invention relates to a plastic pipe whose wall and/or wall parts consist of several layers on the one hand and which consists of several pipe channels on the other. Single-layer plastic pipes made of polyamide for automotive construction are state of the art and are used in a wide variety of ways, e.g. for brake, hydraulic, fuel, cooling and pneumatic lines; see German standard DIN 73 378 "Polyamide pipes for motor vehicles". They must be chemically, thermally, mechanically and hydraulically safe to operate under the conditions encountered in practical use, e.g. as fuel lines.

Single-layer pipes do not adequately meet the requirements under certain operating conditions, e.g. with fuels that contain alcohols (e.g. methanol) and/or aromatic hydrocarbons (e.g. benzene). This can lead to swelling, a reduction in strength and dimensional changes in the pipe, as well as increased diffusion of the fluids that are transported in them through the pipe wall and thus a burden on the environment. Increasingly stricter legal regulations force a reduction in emissions and thus in particular in diffusions.

." Anits|erichäBlelefe!d fc#!B 7.1%8 Head of Department: Klaus Straszewski

DIVISION

Deutsche Tecalemit GmbH

04.02.1995

In addition, for cost reasons, cable bundles are increasingly being used in vehicle construction. These consist of several pre-assembled individual cables that are run parallel and are assembled very cost-effectively in one operation during the final assembly of the vehicle on the assembly line. The main effort for these cable bundles therefore lies in the production of the individual cables and their pre-assembly at the supplier. The additional task is therefore to achieve significant cost savings in production (e.g. through co-extrusion at the supplier) and final assembly (at the car manufacturer) by running several cable ducts in parallel in one pipe.

At the same time, there are stricter requirements for the active and passive safety of vehicles. In the event of a vehicle fire, this means ensuring for as long as possible that the fuel in the fuel lines does not ignite as a result of rapid melting and/or burning of their walls.

Attempts were therefore made to overcome these disadvantages of single-layer plastic pipes by multi-layer pipes for diffusion behaviour (DE 35 10 395, DE 37 15 251, DE 38 21 723,

DE 39 38 497, DE 40 01 125, DE 43 15 117) the flame retardant (DE 38 17 841,

DE 24 53 238, DE 21 40 806, DE 20 25 351) or multi-channel (DE 26 00 859,

DE 26 44 349, DE 26 60 524, DE 28 14 595, DE-G 86 31 085; EP 03 18 434, EP 05 96 507) to be solved. Although some individual successes were achieved for the diffusion behavior (DE 43 09 829,

DE 43 10 884) and flame retardancy (DE 38 40 750); a practical and closed solution to the triple task of diffusion reduction, flame retardancy improvement and multi-channel capability is still lacking.

DIVISION

Deutsche Tecalemit GmbH

04.02.1995

The object of the invention is therefore to create a multi-layer, multi-channel plastic pipe whose properties, e.g. as a plastic pipe system when installed in a motor vehicle, are: low diffusion, sufficient fire protection, parallel transport of fluids, good dimensional stability, good mechanical and technical resilience, good chemical properties, good temperature change behavior, low manufacturing price. The solution to this problem leads to a multi-layer pipe that has the following layer structure from the inside to the outside: inner layer (body), adhesive layer, diffusion layer, foam layer, outer layer, which, however, do not necessarily have to be arranged parallel and concentrically to one another in their layer structure.

In particular, the geometric arrangement of the individual parallel channels, preferably circular, is of considerable additional importance both for functionality and for the manufacturing price. The axes of these channels can be arranged on any geometric line, but preferably a straight line or, if there are more than two channels, on a partial circle. Two adjacent channel walls can be connected directly or, somewhat further apart, by an intermediate web. This intermediate web can be attached on the inside, middle or outside of the arrangement on a partial circle. In all practical applications, the different expansion behavior of the plastics and the generally metallic line connections must be taken into account, which can lead to leaks in the line system in temperature change operation in the border area.
- 40 ⁰ C to + 120 ⁰ C in the vehicle.

The structure of the pipe is based on the geometric arrangement and the manufacturing options. The body of the multi-channel pipe is crucial in terms of strength. On top of this, the diffusion-inhibiting layer is built from further inside to the outside, as well as the flame-retardant layer on the very outside.

·

division

Deutsche Tecalemit GmbH

04.02.1995

The formation of at least one foam layer, preferably with the molding compound polyamide (PA), preferably cross-linked, in the outer covering area of all channels with at least one foam-forming additive whose reaction temperature is higher than the processing temperature, significantly improves the flame protection of the entire pipe. On the one hand, the foaming layer leads to a high level of thermal insulation of the inner layers containing the flammable fluids, with the result that the high temperature only seriously affects the inner layer after a comparatively long exposure time. On the other hand, the foaming leads to the inner layer being effectively protected against the ingress of oxygen for a particularly long time.

In the event of fire, the foam layer requires mechanical reinforcement or additional fire-retardant improvements on the outside. This improvement through the outer layer is achieved by the molding compound preferably consisting of cross-linked polyamides with additional fire-retardant additives.

The mechanical bond between the supporting inner layer, which is preferably made of polyamide and forms the body of the pipe, and the diffusion layer must be ensured by a particularly thin adhesive layer. Due to their frictional connection in the interfaces of these adjacent layers (inner layer to diffusion layer), they prevent them from separating and are responsible for the mechanical stability (e.g. in the event of vibrations or shocks). The selection of the molding compound or molding compound mixture used for this adhesive layer is therefore of considerable functional importance. According to the invention, it can consist of polymeric polyamide plus copolymeric polyacrylic acid esters or of polymeric polyvinylidene fluoride (PVDF) plus copolymeric polymethyl methacrylates.

T£ttALEMlt DIVISION

Deutsche Tecalemit GmbH

04.02.1995

The multilayer pipes are manufactured in a known manner, preferably cost-effectively on coextrusion systems. The individual molding compounds can be cross-linked chemically or by blasting. Further features of the invention emerge from the claims.

The drawing shows in detail, as an example, m channels with preferably the same circular cross-section, as well as η layers:

Figure 1: A cross section through a 4-channel 5-layer pipe in the arrangement

a partial straight line for the channels (m = 4, η = 5).

Figure 2: A cross section through a 4-channel 5-layer pipe in the arrangement

a partial straight line for the channels and with 2 webs each (m = 4, η = 5).

Figure 3: A cross section through a 4-channel 5-layer pipe in the arrangement

a pitch circle for the channels (m = 4, η = 5).

Figure 4: A cross section through a 4-channel 5-layer pipe in the arrangement

a pitch circle for the channels and with 2 webs each (m = 4, η = 5).

Figure 5: A cross section through a 5-channel 5-layer pipe in the arrangement

a partial circle for 4 channels and a central channel as well as one bridge each (m = 5, η = 5).

DIVISION

Deutsche Tecalemit GmbH

04.02.1995

Figure 6: A cross section through a 4-channel 5-layer pipe in the arrangement

a partial circle for the channels and an outer web on the enveloping circle of the channels (m = 4, η = 5).

Figure 7: A cross-section through a section of the pipe according to Fig. 6 under

point flame exposure (m = 4, η = 5).

Figure 8: A cross section through a 4-channel 5-layer pipe in the arrangement

a pitch circle for the channels and an inner web (m = 4, η = 5).

Figure 9: A cross section through a 3-channel 5-layer pipe in the arrangement

a pitch circle for the sector-shaped channels (m = 3, η = 5).

Figure 10: A cross-section through a 4-channel 5-layer pipe in the arrangement of a partial circle for the segment-shaped channels and a central axis for the central, circular channel (m = 4, η = 5).

Figure 1 shows a pipe (15) with four channels (13), which preferably have an identical circular cross-section and whose channel axes (12) are arranged on a division line (17). The individual adjacent channels (13) touch each other directly in the contact zone (18). A closed geometric curve in the form of an enveloping circle (10) fictitiously encloses the pipe (15); an ellipse can also be used as the enveloping circle, the major axis of which corresponds to the outer width of the pipe (15). The layer structure is as follows from the inside to the outside: The inner layer (1) represents the supporting body of the entire pipe (15) and its channels (13). The entire outer

^TEbALEIVHT DIVISIOIM

Deutsche Tecalemit GmbH

04.02.1995

The casing of this body (1) is formed by the adhesive layer (2), the diffusion layer (3), the foam layer (4) and the outer layer (5).

Figure 2 shows a pipe (15) with four channels (13), which preferably have an identical circular cross-section and whose channel axes (12) are arranged on a division line (17). The individual adjacent channels (13) are each connected to one another by two tube webs (6); this leads to hollow channels (19) that have no direct function. A closed geometric curve in the form of an enveloping circle (10) fictitiously encloses the pipe (15); this curve could also be an ellipse, the major axis of which corresponds to the outer width of the pipe (15). The further layer structure is analogous to Figure 1: inner layer (1), adhesive layer (2), diffusion layer (3), foam layer (4), outer layer (5).

Figure 3 shows a pipe (15) with the pipe axis (11) and with four channels (13), which preferably have an identical circular cross-section and whose channel axes (12) are arranged on a partial circle (9). A channel (13) is touched by two adjacent channels (13) in each contact zone (18); this leads to a hollow channel (19) that has no function whatsoever. A closed geometric curve in the form of an enveloping circle (10) fictitiously encloses the pipe (15). The further layer structure is analogous to Figure 1: inner layer / body (1), adhesive layer (2), diffusion layer (3), foam layer (4), outer layer (5).

Figure 4 shows a pipe (15) with four channels (13), which preferably have an identical circular cross-section and whose channel axes (12) are arranged on a partial circle (9). A channel (13) is connected by two adjacent channels (13), each with an inner web (16) and an outer web (14). This leads to four hollow channels (19) each between the inner (16) and outer web (14) and a central hollow channel (19), the

division

Deutsche Tecalemit GmbH

04.02.1995

Axis is identical to the pipe axis (11); these hollow channels (19) have no function whatsoever. A closed geometric curve in the form of an enveloping circle (10) fictitiously encloses the pipe (15). The further layer structure is analogous to Figure 1: inner layer / body (1), adhesive layer (2), diffusion layer (3), foam layer (4), outer layer (5).

Figure 5 shows a pipe (15) with five channels (13), which preferably have an identical circular cross-section and whose four channel axes (12) are arranged on a partial circle (9), or the axis of the inner channel (20) is identical to the pipe axis (11).
One of the four channels (13), whose channel axes (12) are located on the pitch circle (9), is connected to two analogous channels (13), each with an outer web (14), and inside with a wall section (21) of the inner channel (20) as a contact zone; this leads to four hollow channels (19) that have no direct function. A closed geometric curve in the form of an enveloping circle (10) fictitiously encloses the tube (15). The further layer structure is analogous to Figure 1: inner layer / body (1), adhesive layer (2), diffusion layer (3), foam layer (4), outer layer (5).

Figure 6 shows a pipe (15) with four channels (13) which are preferably connected to one another by four pipe webs (6), in the present case designed as outer webs (14). These pipe webs (6) have the function of ensuring the unrestricted expansion behavior of the individual channels (13) when they are installed as pipelines in a motor vehicle during temperature changes from - 40 ⁰ C to + 120 ⁰ C. These requirements of the webs (6) and channels (13) in relation to one another ensure the tightness of the channels (13) in connection with the usually metallic channel connections in operational lines, the thermal expansion behavior of which differs significantly from that of plastics and must therefore be taken into account geometrically. The elastic expansion behavior of the plastics would not be sufficient in this case due to plastic deformation.

DIVISION

Deutsche Tecalemit GmbH

04.02.1995

The envelope circle (10) defines the outer diameter of the pipe (15) in which it is tangent to the outer surface lines of the four pipe channels (13) and the four outer webs (14); the central pipe axis (11) represents the center of the envelope circle (10) in a vertical cutting plane through its axis (11). The channel axes (12), related to the same cutting plane, lie on the pitch circle (9), the center of which is the pipe axis (11).

The pipe (15) is constructed in different layers from the inside to the outside as follows: The inner layer (1) represents the body of the pipe with its four channels (13); this layer determines the strength of the pipe. This inner layer (1) is covered by an adhesive layer (2), which creates the force-locking mechanical bond between the inner layer (1) and the diffusion-inhibiting diffusion layer (3); this adhesive layer (2) is matched to the molding compounds of the two adjacent layers (1) and (2). The external flame protection of the pipe (15) is provided by the two further layers, which form the external structure of the channels (13) and the outer webs (14) on the enveloping circle (10); these are the foam layer (4) and the outer layer (5). The foam layer (4) contains at least one foaming additive whose reaction temperature is higher than the processing temperature of the pipe during extrusion; the outer layer (5) contains at least one flame-retardant additive. The preferential cross-linking of the layers (3), (4) and (5) provides additional stability, which has an advantageous effect in the event of external flame or heat exposure.

Figure 7 shows the external point-like flame effect (7) on the pipe (15) or in relation to a channel (13). As soon as the reaction temperature is higher than the processing temperature, the foam layer (4) foams (8) and good thermal insulation is formed against the fluid in the channel (13), e.g. fuel. At the same time, at least one additive in the outer layer (5) inhibits the properties of the

TECALEMIT DIVISION

Deutsche Tecalemit GmbH

04.02.1995

fire of this layer, which is set to be self-extinguishing. Additional cross-linking, either chemical or by radiation, in the foam layer (4) and the outer layer (5) increases the flame retardant effect considerably.

Figure 8 shows a pipe (15) with four channels (13) which are connected by four pipe webs (6), in this case designed as inner webs (16). The function of these pipe webs (6) is the same as described in Figure 1. The enveloping circle (10) is tangent to the outer surface lines of the four channels (13). The arrangement of the pipe axis (11) and the four channel axes (12), as well as the design and function of the layers (1), (2), (3), (4), (5) is analogous to Figure 1 to Figure 6. Due to the geometric design of the pipe (15), the layers (2) to (5) largely envelop the entire channels (13) as well as the outer contour of the inner webs (16); the surface of the entire pipe is correspondingly larger.

Figure 9 shows a circular pipe (15) with m = 3 sector-shaped channels (13) of the same cross-section, the channel axes (12) of which lie on a partial circle (9). The wall sections (21) of two adjacent channels (13) are pipe webs (6) directed radially outwards. The inner layer (1) forms the supporting body of the entire pipe (15); its outer geometric shape is preferably circular. The adhesive layer (2), the diffusion layer (3), the foam layer (4) and the outer layer (5) are arranged radially outwards on top of this. The outer enveloping circle (10) is identical to the outer diameter Da of the pipe (15) with the pipe axis (11).

Deutsche Tecalemit GmbH

04.02.1995

Figure 10 shows a circular pipe (15) with m = 4 channels (13) of the same cross-section, whereby three channels (13) are segment-shaped and one inner channel (20) is circular. The axis of the inner channel (20) is also the pipe axis (11); the channel axes (12) of the segment-shaped channels (13) lie on a partial circle (9). The contact zones (18), which are also wall sections (21), of two adjacent segment-shaped channels (13) are radially outward-facing pipe webs (6); the wall sections (21) of the inner channel (20) to the segment-shaped channels (13) are identical to its wall. The inner layer (1) simultaneously forms the supporting body of the entire pipe (15); its external geometric shape is circular. Arranged radially outwards are the adhesive layer (2), the diffusion layer (3), the foam layer (4) and the outer layer (5). The outer enveloping circle (10) is identical to the outer diameter Da of the pipe (15).

Derived from Figures 6 and 8 with the extreme layers of the pipe webs (6) as outer (14) or inner webs (16), numerous further layers of such webs (6) are now conceivable, e.g. in intermediate layers; further designs m > / = 3 with l=/<n = /<6 layers can also be realized for the number m of channels (13). Likewise, certain layers can be combined in their function, e.g. the diffusion layer (3) with the molding compound C and the foam layer (4) with the molding compound D in a new layer (3/4) with the new molding compound F,

Claims (29)

Multi-layer, multi-channel plastic pipe, consisting of m fluid-carrying channels and η layers (m > 1, η > 1; each integer), preferably with circular channel cross-sections, dimensionally determined by its main dimensions (channel inner diameter, pipe outer diameter, number of channels, number of layers, channel wall thickness, web thickness, channel division), manufactured using the coextrusion process, used in the automotive sector for brake, compressed air, hydraulic, fuel and cooling lines, the wall of which has at least one load-bearing, diffusion-reducing, force-fitting, foamable and flame-retardant layer or at least one combination of at least two relevant layer features, characterized in that the tube (15) and/or its elements are constructed as follows; &bull; materially from the inside to the outside, the inner layer (1) made of a molding compound A of a thermoplastic polymer, the adhesive layer (2) made of a molding compound mixture B with a minimum 50% mass fraction of a thermoplastic polymer and a maximum 50% mass fraction of thermoplastic copolymers, the diffusion layer (3) made of a molding compound C of a thermoplastic polymer, the foam layer (4) consists of a molding compound D of a thermoplastic polymer, preferably cross-linked, which contains at least one blowing agent-containing additive whose reaction temperature is higher than the processing temperature, TECAl ₁ EIVHT Deutsche Tecalemit GmbH 04.02.1995 the outer layer (5) made of a molding compound E of a thermoplastic polymer, preferably cross-linked, which contains at least one flame-retardant additive; geometrically, the division on which the axes (12) of the channels (13) are arranged is located on at least one geometrically defined division line, the pipe envelope represents a geometrically defined curve, preferably an envelope circle (10), and the areas of the cross sections of the m channels (13) are preferably identical. 2. Multi-layer, multi-channel plastic pipe according to claim 1) characterized in that the geometric dividing line is preferably a dividing line (17). 3. Multi-layer, multi-channel plastic pipe according to claim 1), characterized in that the geometric dividing line is closed and preferably forms a partial circle (9). 4. Multi-layer, multi-channel plastic pipe according to claim 1) to 3) characterized in that the walls of adjacent channels (13) touch each other in a contact zone (18). 5. Multi-layer, multi-channel plastic pipe according to claim 1) to 3) characterized in that the walls of adjacent channels (13) are connected by at least one pipe web (6). SIEBE TECÄL:i=IV!!T ÖEV3SIOM Deutsche Tecalemit GmbH 04.02.1995 6. Multi-layer, multi-channel plastic pipe according to claim 1) to 5) characterized in that the pipe web (6) is designed as an inner web (16). 7. Multi-layer, multi-channel plastic pipe according to claim 1) to 5) characterized in that the pipe web (6) is designed as an outer web (14) and preferably in its outer contour is tangent to the enveloping circle (10) of the pipe (15). 8. Multi-layer, multi-channel plastic pipe according to claim 1) to 7) characterized in that the pipe web (14) is designed as an outer web (14) plus an inner web (16). 9. Multi-layer, multi-channel plastic pipe according to claim 1) to 8) characterized in that the inner layer (1) has a layer thickness Sl of at least Sl > / = 0.5 mm. 10. Multi-layer, multi-channel plastic pipe according to claim 1) to 9) characterized in that the adhesive layer (2) has a layer thickness S2 of less than S2 < 0.1 mm. 11. Multi-layer, multi-channel plastic pipe according to claim 1) to 10) characterized in that the diffusion layer (3) has a layer thickness S3 of at least S3 > / = 0.1 mm. Deutsche Tecalemit GmbH 04.02.1995 12. Multi-layer, multi-channel plastic pipe according to claim 1) to 11) characterized in that the foam layer (4) has a layer thickness S4 of at least S4 > / = 0.3 mm. 13. Multi-layer, multi-channel plastic pipe according to claim 1) to 12) characterized in that the outer layer (5) has a layer thickness S5 of at least S5 > / = 0.2 mm. 14. Multi-layer, multi-channel plastic pipe according to claim 1) to 13) characterized in that the main dimensions of the channels (13) with outer web (14) for the inner layer inner diameter Dis, the inner layer outer diameter Das, layer thicknesses (Ss = S) and their tolerances correspond to the German standard DIN 73 378 for the diameter range Da > / = 4 mm and the wall thickness range S > / = 0.75 mm, or Da > / = 6 mm and S > / = 0.5 mm. 15. Multi-layer, multi-channel plastic pipe according to claim 1) to 13) characterized in that the main dimensions of the channels (13) with inner web (16) for the channel inner diameter Dik, the channel outer diameter Dak, channel thickness Sk=Sl+S2+S3+S4+S5 and their tolerances correspond to the German standard DIN 73 378 for the outer diameter range Da > / = 6 mm and the wall thickness range S > / = 1.5 mm. 16. Multi-layer, multi-channel plastic pipe according to claim 1) to 15) characterized in that the moulding compound A of the inner layer (1) consists of polyamide. Deutsche Tecalemit GmbH 04.02.1995 17. Multi-layer, multi-channel plastic pipe according to claim 1) to 16) characterized in that the molding compound mixture B of the adhesive layer (2) consists of polymeric polyvinylidene fluoride and copolymeric polymethyl methacrylates. 18. Multi-layer, multi-channel plastic pipe according to claim 1) to 17) characterized in that the molding compound mixture B of the channel adhesive layer (2) consists of polymeric polyamide and copolymeric polyacrylic acid esters and their derivatives. 19. Multi-layer, multi-channel plastic pipe according to claim 1) to 18) characterized in that the molding compound C of the diffusion layer (3) consists of polyvinylidene fluoride. 20. Multi-layer, multi-channel plastic pipe according to claim 1) to 19) characterized in that the molding compound D of the foam layer (4) consists of polyamide. 21. Multi-layer, multi-channel plastic pipe according to claim 1) to 20) characterized in that the molding compound E of the outer layer (5) consists of polyamide. 22. Multi-layer, multi-channel plastic pipe according to claim 1) to 21) characterized in that the chemical molding compound E of the outer layer (5) contains a physical mass fraction of max. 15% conductive carbon black. &iacgr; 1 TEC AILEIVI IT DI VISION » &bgr; Deutsche Tecalemit GmbH 04.02.1995 23. Multi-layer, multi-channel plastic pipe according to claim 1) to 22) characterized in that the molding compound mixture C is cross-linked with the diffusion layer (3). 24. Multi-layer, multi-channel plastic pipe according to claim 1) to 23) characterized in that the molding compound mixture A is cross-linked with the inner layer (1). 25. Multi-layer, multi-channel plastic pipe according to claim 1) to 5), 7) to 24) characterized in that the outer web (14) is preferably a component of the adhesive layer (3), the diffusion layer (3), the foam layer (4) and the outer layer (5). 26. Multi-layer, multi-channel plastic pipe according to claim 1) to 5), 7) to 25) characterized in that the inner web (16) preferably consists of the 5 layers (1), (2), (3), (4) and (5). 27. Multi-layer, multi-channel plastic pipe according to claim 1) to 26) characterized in that the surfaces of the channels (13) form a circular cross-section. 28. Multi-layer, multi-channel plastic pipe according to claim 1), 3) to 13) and 16) to 26) characterized in that the surfaces of the channels (13) form a sector-shaped cross-section. division Deutsche Tecalemit GmbH 04.02.1995 29. Multi-layer, multi-channel plastic pipe according to claim 1), 3) to 13) and 16) to 26) characterized in that the surfaces of the channels (13) each partially form several segment-shaped and one circular cross-section. 30, Multi-layer, multi-channel plastic pipe, according to claim 1) to 29) characterized in that the chemical molding compound A of the inner layer (1) contains a physical mass fraction of max. 15% conductive carbon black.