CA2126246A1 - Plastic fluid duet, in particular for convecting a vehicle fuel tank to the vehicle engine - Google Patents

Abstract

2126246 9410491 PCTABS00166 The invention relates to a fluid pipe made of plastic material, in particular for connecting the fuel tank of a vehicle to the engine of said vehicle. In accordance with the invention, the pipe consists of an outer tubular wall (110) made of a multi-layer material, with an internal layer (113) with low permeability to the fluid concerned and an external protective layer (114), and by an internal partition (112, 120) arranged inside this external tubular wall (110) to delimit a plurality of passages, said partition being in turn made of single-layer material compatible with said fluid.

Description

WO94 / 10491 21 ~ 6 2 4 6 PCT / FRg3 / 01060 ~ Fluid pipe re ~ made of plastic .
¦ The invention relates to fluid pipes made of plastic, in particular but not exclusive-the pipes used to connect the storage tank i fuel from a vehicle to the engine of this vehicle.
The invention relates more particularly to fluid lines (liquid or liquid state) gas) fitted to motor vehicles and one can cite, in addition to the fuel lines, the lines tions associated with various fluids in the liquid state or mixtures liquids (lubricants, coolant, liquid windshield washer, etc .... ~, or gaseous (cooling gas for air conditioning ~ ion for example).
Although one of the very particular technical areas directly concerned either that of vehicles (vehicles automobiles or more generally motorized type vehicles any). The invention is however also applicable to the area of fixed installations in which it is néces ~ area to transport various fluids by pipelines tions, for example generators. The term fuel must also be understood in a general sense, covering various types of fuels used for the supply of internal combustion engines (gasoline, diesel, etc ...) ~
For dozens of years, we have equipped ~
! 25 plastic pipe motor vehicles I ~ produced in the form of a single flexible single-layer tube, therefore easy and inexpensive to manufacture. Performance at look at the fuel permeability are however appeared increasingly insufficient in view of the requirements these in the matter. As an indication, the permeability currently authorized in rance must not exceed 2,5 g / m2 / hour.
This has led manufacturers to study fuel lines made of mu-lti- material layers, in order to assign to the internal layer (s) the : "~
2121i ~

function of ensuring the desired low permeability, and has the outer layer the function of providing mechanical protection, especially resistance to gravel or sharp objects.
This teaching is for example illustrated by the documents ; 5 DE-C-4 001 125, DE-C-4 006 870 and JP-A-4 171 382.
These materials offer very high performance ~ interesting, but they have the disadvantage of ~ being ! much more expensive than traditional materials of the type single layer.
In addition, it may be necessary, for example example for petrol or diesel injection engines, d having to channel two separate fuel flows, with a feed flow to the injection rail of the engine and a return flow of excess fuel (the pump injection ~ both at constant flow) flowing in direction reverse to the tank. For engines ~ injection to gasoline, we can find in addition a flow of vapors of fuel to be recovered ~ rer ~ However, each line must then individually present the characteristics required, both in terms of permeability and in terms of mechanical resistance. Therefore, the use of materials multi-layer is practically excluded in such an applica-- tion, due to the prohibitive price of a double or triple pipeline made with such materials.
One solution may be to juxtapose conventional piping and hand them ~ enir with a common protective sheath, as illustrated in the document EP-AO 235 9S9.
However, this solution appears to be very contra-inconvenient insofar as the assembly obtained lends itself poorly to bending: this is particularly the case for canali-fluid sations mounted on vehicles because they are often conformed with complicated elbows and in directions which are imposed by geometric constraints specific to each vehicle. Furthermore,. the sheathed assembly is `W094 / 1049l 2126 ~ 16 PCT / FR93 / 01060 bulky, and its manufacturing cost is high.
Another solution is to provide a wall to internal partitioning defining passages, the whole being single-layer and of the same thickness, as described in documents FR-A-2 293 652 and FR-A-2 511 747. This set is better for bending, but its performance in terms of permeability remains limited, and an assembly produced in multi-layer material would be both complex to manufacture and very expensive.
It therefore appears a need to be able to have fluid pipes made of plastic, which are both efficient and low manufacturing cost tion.
To resolve this problem, those skilled in the art have more generally from various lessons he can find in existing liquid and / or gas pipelines, these lessons being either directed towards an approach of pipe type with multi ~ layer outer wall and without partitioning (reference may be made to documents JP-A-3 097 531 and DE-U-81 33466), possibly in a juxtaposed set held by a band (FR-E-75 632) or in a sheath (US-A-2 971 538, assuming that the protective film constitutes a layer) ~ either directed towards a pipe type approach with one-layer exterior wall internally partitioned ( may refer to documents US-A-4,236,953, EP-A-0,207 102, EP-A-0 264 102, DE-U-78 21145, and in document GB-A-2 258 694 observing, however, that this document has been published after the priority dates currently claimed quées ~.
; 30 The technological background can be supplemented by mentioning essentially metallic pipes, possibly coated with an insulation coating or protection (documents DE-A-4 021 563, DE-C-387 330, CH-A-539 809), or other even more distant pipes of the domain concerned (documents US-A-4,784,104 and US-A-2,475 WO94 / 1049l PC ~ / FR93 / 01060 21262 ~

635). Document WO-A-91/14124 can finally be cited for illustrate a channel ~ ion made of fiber composite material glass or carbon, the interior passages of which are coated with a sealing skin when fluid must to borrow, to compensate for the porosity of the partitioning in fibers, and the outer wall of which is coated with a fine protective layer: this teaching of a whole diapers is practically inapplicable in the field of flexible fluid lines fitted to vehicles automobiles, due to its structure and cost prohibitive.
The object of the invention is to design a channel ~
: tion of fluid which is both efficient and low manufacturing cost, while lending itself particularly well in the case of fuel for vehicles equipped with a _ injection, petrol or diesel.
It is more particularly a pipe fluid r ~ made of plastic, especially for .- connect the fuel tank of a vehicle to the engine . 20 of said vehicle, characterized in that it consists of an outer tubular wall made of a multi-material I layers, said material comprising an internal layer ¦. low fluid permeability ~ affected and an outer layer ¦ of protection, and by an interior partitioning arranged at the interior of this outer tubular wall to delimit ter a plurality of passages, said partitioning being meanwhile made of a material. compatible single layer 'with said fluid.
In accordance with a particular embodiment, the : 30 multi-layer material constituting the outer wall additionally has a layer of adhesive between the layers internal and external of said external wall.
In accordance with another particular embodiment bind, the multi-layer material constituting the wall outer layer has a barrier layer 212 62 4 ~ ", with regard to at least one of the components of the fluid concerned.
Advantageously then, the constituent multi-layer material the outer wall also has a layer of adhesive between the intermediate barrier layer and the layer external protection. The inner and outer layers of the outer wall can for example be made in polyamide.
Advantageously, the single-layer material constitutes If tif of internal partitioning 1r is chosen from the group ¦ 10 comprising polyamides, polyethylene, polypropylene, and recycled materials from p ~ quoted materials.
It is further possible to provide that the mono- material component layer of the interior partitioning comprises in addition to additional charges, such as a charge of graphite to make this interior partitioning conduc-electricity generator.
In accordance with another particular characteristic ~ ~ lière, the interior partitioning is at least partly - ~ unitary integral with the inner layer of the wall . 20 outdoor.
According to a first variant, the internal partitioning ,., j rieur consists of an inner tubular wall I held coaxially in the outer tubular wall by spacers which extend radially along the axis common to the two walls.
According to another variant, the internal partitioning Laughter is constituted by a transverse internal veil.
According to another type of variant, the partitioning interior is constituted ~ by three sails extending radially-30 ment from the axis of the outer wall. In accordance to a particular characteristic of this variant, the ~ three sails meet at the axis of the wall exterior, and define ~ three dihedral whose angles are neighbors of 116, 116 and 128 respectively, or define three dihedrons of the same angle.

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21f ~ 624 ~

According to another variant, the internal partitioning laughing consists of an inner tubular wall with transverse internal veil maintained coaxially in the outer tubular wall by spacers which extend radially along the axis common to the two walls.
According to yet another variant, the interior partitioning consists of two distant internal walls, one of the other and delimiting, with the outer tubular wall, two side passages and a central passage.
Preferably then, each internal wall is : connects directly to a partial internal layer of the outer wall, so as to form a continuous wall aya ~ t in section a substantially circular shape, the parts residual of this outer wall then forming two . 15 connecting fabrics which are made of multi-layer material.
- Other characteristics and advantages of the invention will emerge more clearly from the description which will follow and attached drawings, concerning an embodiment ¦ particular, in r ~ reference to the figures where:
1 20 - Figure l is a schematic overview an installation that equips a motor vehicle for , connect the fuel tank to the fuel injection engine ', this vehicle, said installation comprising a pipeline according to the invention, allowing both, and on the main length of the route concerned, the passage of the feed fuel and return fuel;
- Figures 2a and 2b illustrate in cross-section versal (section along II-II in Figure l), and to a scale very enlarged, two possible variants of pipes according to the invention, respectively with fins spacing integral with the outer wall (which has three layers here), or with space fins-integral with the inner wall, the outer wall comprising in this case four layers;
- Figures ~ c and 2d are other sections according to 21 2 ~ 2 1 ~

II-II illustrating two other variants including the partitioning interior is defined by a transverse internal veil;
- Figures 2e and 2f illustrate two more other variants, with interior partitioning consisting of three radial sails, the angular arrangement of which is here intended for the case where the fuel is diesel;
- Figure 3 is a schematic overview an installation which differs slightly from that of the figure l, insofar as the fuel line allows plus the passage of fuel vapors from the tank see ;
- Figures 4a and 4b illustrate in cross-section versal (section according to IV-IV of Figure 3), and to a scale j very enlarged, two possible variants of pipes, respectively with an outer wall ~ three layers and four layers;
~ - ~
- Figures 4c and 4d are other sections according to IV-IV illustrating two other variants including the partitioning interior is different;
- Figures 4e and 4f illustrate two more other variants, with internal partitioning consisting of two internal walls distant from each other, in the form d2mi-circular.
~ ~ Figure l illustrates an installation intended for -1 25 to equip a motor vehicle, to connect the tank of fuel lO to the engine ~ injection ll of this vehicle. The representatisn of this installation, most of which components are already known, mainly for the purpose of locate the fuel line l00 used in this installation, which pipeline has a structure particular, according to the invention, which will be described more further referring to Figures 2a to 2f.
It goes without saying, however, that this application particular, both with regard to the type of fluid and with regard to of the field of use concerned, must in no way be : `~

21 ~ .624 ~. .` -. ~.

considered limiting in the context of 1 ~ invent ~ ion.
To simplify, we will only speak of a channeling of fuel in the following description.
The fuel tank 10 thus comprises a ; 5 fuel pump 12, fitted with a suction plate 13 to which two portions of pipe 14 are connected and 15, one of which is used to power the engine with the fuel sucked in, and the other when the fuel is returned excess exiting downstream of the injection rail of this engine.
One succeeds in using a single line 100, which ! is connected to sections 14 and 15 by a suitable connector lOl.
At the other end of the fuel line 100, there is finds a similar connection 102, from which two sections leave of pipes 16 and 17, the first serving for food of the engine into fuel, and the other when fuel returns excess. In this case, the pipe section 16 is equipped of a fuel filter 18, but it goes without saying that such filter could as well be arranged on the section of departure 14 near the reservoir. Downstream of the filter fuel 18, there is an injection ramp 19, of which distinguishes certain injectors 20. At the downstream end of this injection rail 19, there is finally a regulator of pressure 21, from which the pipe section 17 starts, which ensures the return of excess fuel towards the tank lO.
We have also illustrated other components that complete the above installation, these components being of conventional type, so that they do not will not be described in detail. There is thus an equipment carburan vapor recovery ~, with a recuperator vapors 22 to which leads a pipe 23 starting from a non-return valve 24. This valve 24 is connected to the motor.
by a nozzle 25, and to the tank by a pipe associated 26 leading to a non-return valve 27, downstream from which there are a plurality of air hoses W094 ~ 1049l PCT / FR93 / 01060 624 ~

free 28. There is also associated classic equipment when filling the tank, with a filling tube 29, at the entrance of which is provided a cap housing filling 30, this tubing being further here equipped of a backdraft hose 31.
Thus, the fuel sucked by the pump 12 of the tank 10 passes through the pipe section 14, then enters line 100, to finally reach the feed section 16 leading to the injection rail of the engine. For excess return fuel, the liquid follows the trunk 17, then, from the fitting 102, passes also in the aforementioned line 100, finally out of it, downstream of the associated fitting 101, opening into the return section 15 connected to the suction plate 13 and finally in the tank 10.
We will now describe in more detail different modes of execution of the structure of the pipeline fuel 100 above, with reference to FIGS. 2a to 2f, ~ ueIles illustrate as examples six variants of execution according to the invention.
In FIG. 2a, the pipe 100 is made up : killed by two tubular walls 110 and 120, which are essentially coaxial and kept at a distance from one The other by spacers 112 (here the number of three). These two tubular walls 110 and 120 are here circular section, but this does not naturally constitute as an example, and other forms of sections preferably admitting a center of symmetry. The axis common to the two walls 110 and 120 is here referenced X. The inner wall 120 thus delimits a central passage 121, and the outer wall 110 delimits, with this wall interior, an annular passage 111, passages 121 and 111 thus delimited allowing to channel two different flows fuel. The inner tubular wall 120 and the spacing fins 112 thus define a partitioning :;

2 ~ 2 ~ i246 interior, which is made of compatible single-layer material with the fluid concerned.
In this case, the spacing fins 112 are integral with the outer wall llO, and extend radially-ment along the axis X so as to ensure, by their free edge 112.1, the maintenance of the inner wall 120 in the wall outdoor llO. The inner wall 120 is therefore here desoli-; dar ~ isée of ~ the unitary assembly constituted by the outer wall IlO and the ~ spacing fins 112, which is 10 ~ interesting ~ when it comes to bending the pipe, in the extent that ~ the radial fibers ~ ement ~ outer fins spacing and the outer wall are subjected to lower tensile forces in the case of radius of weak ~ neck ~ rbure.`The ~ free edge lI2.1 of ~ fins 112 may 15 ~ be ~ straight ~, or alternatively have undulations which constitute ~ openings ~ of communication between c ~ es ~ annu ~ laires ~ adjacent6 defined ~ s by ceæ fins, ce which ~ `pe ~ ~ then ~ to balance the pressures between these 20 ~ Conformémént ~ a one ~ caract ~ ristique ~ of the invention, the ~ wall ~; ~ outside ~ llO ~ is ~ additionally r ~ made of a material ; multi-layers, ~ c ~ that is to say ~ constituted ~ by at least two co w hès`, ~ with ~ an ~ inner layer; low permeability to fluid ~ con ~ c ~ ern ~ and a ~ outer ~ protective layer ~.
25 ~ In the ~ representation do ~ nn ~ e in Figure 2a, the material ~ iau ~ multi-layer ~ thus has an internal layer 113 at ~ low permeability ~ to the fuel concerned and a layer 'external 114 intended ~ e to ensure mechanical protection and ; ~~ eventuLlement ~ also chemically. It will be possible to predict ~ if ~ the ~ barrier ~ function is exclusively provided by the inner layer) between the inner layer 113 and the layer external ~ ll4, a layer of adhesive (variant not shown).
x ~ ~ We have illustrated ~ in Figure 2a another special case where it between layers 113 and 114, an intermediate layer is provided ,, ~ -35 diaire 115 forming a barrier with regard to at least one of the , ~

, ,, ~,.

`, 212624 ~

components of this fuel. The outer wall 110, gr ~ ce à
its multi-layered structure, thus ensures for the pipe 100 at a time the low permeability to the gaze fuel, and mechanical resistance to attack outside. In addition, the intermediate layer forming barrier 115 is protected by adjacent layers, both against attacks by fuel (through the wall 113), that against external aggressions, of mechanical type or chemical t by wall 114). We can thus use, as constituent material of the intermediate layer forming barrier, a material of the type commonly used in the food sector, because this material is in no case direct contact with fuel. The choice of material constituting the other layers may allow them to be made perform an additional barrier function ~ especially at ~ - look at other fuel components) It is particularly advantageous to provide that the inner layer 113 and the outer layer 114 of the wall exterior 11O are made of polyamide. For the diaper internal 113, provision may in particular be made of a polyamide 6, 6-6, 11 or 12, and for the outer layer 114, a polyamide 12 or - ~ 11. Although it is not shown here, it goes without saying that we can also provide a varnish or a layer protective exterior, forming a cladding surrounding the outer layer 114, for example in a rubber material teux, which allows in the case of such an application to further improve the temperature resistance (which is particularly interesting when the pipeline from fuel passes in the vicinity of the engine), that with regard to anti-shock qualities of this pipe.
As illustrated here, we can plan that the spacing fins 112 are integral unitary-ment of the inner layer 113 of the outer wall, this solidarity advantageously resulting from the coextrusion itself of the corresponding profile. These fins are then produced .
~ 12624 ~

polyamide.
The inner wall 120 has the sole function of constitute a partition, delimiting the passage central 121 and the annular passage 111. These passages are both borrowed by the same fuel, so that we has managed to completely free itself from all constraints of permeability for the interior wall 120 of the pipe ~ 100. This interior wall is also completely protected ¦ by the above-mentioned outer wall llO, so that one 1 10 overcomes any mechanical strength constraint. Of ¦ it is therefore possible to use less materials "noble" to achieve this interior wall 120. It will be particular possible to use a single layer material such than polyamide, high density polyethylene, polypro-pylene, or a recycled material from materials cited above. We can easily understand that the unit cost of such a pipeline is considerably reduced due to the fact of the few constraints for the interior wall 120 of this pipe, which wall should only have one sufficient fuel resistance, which is easy to obtain with the aforementioned materials.
In some cases, it may be interesting to provide that the material of the interior wall 120 also includes additional charges, such as graphite charges aimed at making this wall integrated electricity conductor. In this case, the wall ¦ interior 120 provides an additional anti-¦ static for the fuel line.
The absence of rigid constraints for the realization tion of the inner wall 120 also makes it possible to provide a wall of small thickness, notably smaller than the thickness of the outer wall llO which is about it made of a multi-layer material. In particular, we may use a thickness of no more than 0.5 mm to the inner wall 120, while the outer wall 110 - '2126241 ~

will present in practice a thickness close to 1 mm.
So yue that is easy to understand, the wall interior 120 behaves more like a central ~ me for the outer wall llO, so that this wall interior also helps to effectively combat any risk of "cracking" of the pipe in the event of pipe bending with very small radii curvature. Such a risk of crunching was particularly sensitive in the context of conventional pipelines mono-layer type, and the possible cladding with two pipes juxtaposed did not eliminate this risk.
Although it is possible to use one or the other passages 111 and 121 for the two fluid flows, there may in certain cases prove to be interesting to prefer a passage rather than the other. This is so for example in the present case where the line 100 is used to connect the ; fuel tank of a vehicle to the engine of said vehicle ! the, using the central passage 121 to channel the fuel supply, and the annular passage 111 for the '20 return of excess fuel to the reser ~ oir. Indeed, we knows that some fuels are sensitive to low levels thermal, so ~ ue the annular passage borrows by heated air bubbles and / or fuel (due to direct vicinity of the engine) constitutes a true thermal protection for the central passage which is used by the supply fuel.
In FIG. 2b, a variant of this has been illustrated.
mode of carrying out the invention. According to this variant, the spacer fins 122 are now secured to the 30 interior wall 120, and extend as before radially along the X axis so as to ensure by their edge free 122.1 the maintenance of the interior wall 120 in the exterior wall llO. Such an embodiment is perhaps be more delicate in terms of manufacturing the whole unit consisting of the inner wall 120 and its ~?
21 ~ 62B ~ i) - protruding fins 122, but an advantage is not obtained negligible since these spacers are then made of a little "noble" material, in particular that used to make the interior wall 120.
The variant illustrated in Figure 2b differs also from the previous variant insofar as the ~ multi-layer material constituting the outer wall llO
! here has an additional layer of adhesive 116 between the j intermediate layer 115 forming a barrier and the layer j 10 external 114 of protection. Such a layer of adhesive may Intéressante prove to be interesting in certain cases, for example when the constituent materials of the layer 115 forming a barrier and the outer layer 114 are hardly compatible - wheat.
Again, we can use, for layers internal 113 and external 114 a material such as polyamide, while the material constituting the interior wall 120 may be a single-layer material of the type of materials previously indicated for the already described variant ~. In in addition, it will still be possible to provide a thickness at more equal to Ot5 mm for the inner wall, and for associated spacers, while the outer wall rieure llO will generally have a thickness close to l mm.
The above examples are intended to show that 1 we can consider a low (two) or large number (four or more) of layers for the material of the outer wall of the fuel line.
The use of polyamide for this wall exterior ensures the low permeability of the whole of the pipeline to the outside, as well as its mechanical and possibly also chemical resistance against external aggressions. The fact that no characteristic binding of permeability or mechanical resistance does required for the inner wall allows the use of 2 1 2 6 2 4 it?

much less expensive materials, which has the effect significantly lower the manufacturing cost of the pipeline.
Finally, there are other advantages to be mentioned.
appendices added to the advantages already mentioned more top: due to the uniqueness of the pipeline, we decrease side clutter effect, and forming is made possible together in one operation, which allows both to lower the time and cost of assembly, and also to halve the number of fittings required.
In FIGS. 2c and 2d, the pipe 100 is constituted by an outer tubular wall 110 of axis X, with the interior of which is arranged a transverse internal veil sal 212: the wall 110 and the internal veil 212 define - 15 thus two adjoining passages 211.1, 211.2 which allow channel two different fuel flows ~ This internal veil - 212 thus defines another interior partitioning, which is ! made of single-layer material compatible with the fluid concerned.
The internal veil 212 constitutes a partition of se ~ paration, and this partition may be diametrical or not.
In this case, the internal veil 212 is arranged at a distance not zero, denoted d, of the axis X of the outer wall llO. A
such particular mode of execution will be particularly suitable in case the fluid is diesel: indeed, we will use then the larger section 211.1 for diesel feed, and passage 211.2 of smaller section ~; for the return of excess diesel to the tank, the distance d then being determined in such a way that these passages have respectively the same section as the two pipes (single-pipe type with circular section) usually used for feeding and returning diesel.
For example, if the pipe according to the invention is planned to replace the assembly consisting of a ., WO94 / l0491 PCT / FR93 / 0l060 2126 2 4 ~
. .

8 mm internal diameter single-tube pipe (for diesel supply) and a 6-pipe single-pipe mm inside diameter (for the return of excess diesel), we can choose a 10.5 mm diameter pipe interior, and an internal veil positioned at a distance d of 1.5 mm from the X axis.
The outer wall llO is again produced in a multi-layer material, with an internal layer 113 to low permeability to the fluid concerned and an outer layer protective (with possibly a layer between them `` adhesive). Here we find the additional barrier layer 115 (Figures 2c and 2d) and the adhesive layer 116 (Figure 2d), with the same functions and the same advantages as those i mentioned above.
15As illustrated here, we can plan that the internal veil 212 is unitary unitary of the inner layer 113 of the outer wall 110, this solida-rite advantageously resulting from the very coextrusion of the corresponding profile. This single-layer internal veil is then advantageously made of polyamide.
'Passes 211.1 and 211.2 are both taken from ~ ted by the same fluid, so that one is as pr ~ cédem-Libre ment free of any permeability constraint for the veil I internal 212 corresponding.
¦ 25The absence of rigid constraints for the realization tion of the internal veil 212 also makes it possible to provide a thin wall, that is to say of appreciable thickness-slightly weaker than that of the outer wall llO which is as for it made of a multi-layer material. In particular, a thickness close to 0.8 may be used mm for the internal wall 212, while the external wall In practice, it will present a thickness close to 1 mm.
By choosing in addition an internal diameter close to 10 mm, we get a pipe that provides the same flow possibilities than a conventional two-set W094J1049l PCT / FR93 / 01060 ~ .12 ~ Z4 ~.

independent tubes with internal diameters 6 and 8 mm respectively (the outside diameters being 8 and 10 mm): the outer surface is therefore considerably reduced.
It should also be noted that the veil intermediate 212 forming a partition between passages 211.1 and 211.2 authorizes a heat exchange for the fluid: the passage 211.2 used here by air bubbles and / or heated fuel (after passing near the engine) makes it possible to reheat the fuel for which is interesting if you use fuels sensitive to low thermal levels (diesel in particular link).
In Figures 2e and 2f, the line 100 is constituted by an outer tubular wall 110 of axis X, with inside which are arranged three internal sails 312 extending radially from the X axis, from this Extérieure outer wall. The outer wall 110 and the three sails , 312 thus delimit three contiguous passages 311.1, 311.2 and ! 20 311.3, which channel two different flows of fluid: in fact two passages are used (here the passages 311.1, 311.2) to channel a first flow, while the third pass (here pass 311.3) allows to channel a second stream. These three radial sails 312 define thus another interior partitioning, which is carried out in single-layer material compatible with the fluid concerned.
The three sails 312 here constitute partitions separation radials which meet at the axis X of the outer wall 110, and these partitions may be arranged to ~ d ~ finish three dihedral angles ~ predeter-undermined. In this case, the sails 312 are arranged so as to define three dihedrons whose angles a, b, and c are neighbors of 116, 116 and 128 respectively. Such a mode particular execution will be especially suitable in case where the fuel is in diesel: indeed, we will then use WO94 / 1 ~ 91 PCT / FR93 / 01060 ~ 21f ~ 62 ~ ~ 18 the two passages 311.1, 311.2 of smaller section (an ~ les a and b) for diesel fuel, and passage 311.3 of larger section ~ angle c) for the return of diesel fuel excess to the tank, so as to obtain the same passages , 5 sections than the two pipes (of the mono-tube type with circular section) usually used for food tion and return of diesel.
For example, if the pipe according to the ihvention is planned to replace the assembly constituted by a single-pipe 8 mm inside diameter tpour diesel fuel supply) and a 6-pipe single-pipe mm inside diameter (for the return of excess diesel), we can choose a pipe of 10.8 mm in diameter interior, with radial sails whose thickness is close to 0.8 mm.
The outer wall llQ is again produced in a multi-layer mat ~ riau, with an inner layer 113 to low permeability to the fluid concerned and an outer layer protective (with possibly a layer between them adhesive). Here we find the additional barrier layer 115 (Figures 2e and 2f) and the adhesive layer 116 (Figure 2f), with the same functions and advantages as above.
As illustrated here, we can plan that the radial sails 312 be unitary integral with the inner layer 113 of the outer wall 110, this solidarity advantageously resulting from coextrusion even of the corresponding profile. These single-layer internal sails are then advantageously made of polyamide.
Passages 311.1, 311.2 and 311.3 are all three borrowed by the same fluid, so that one is in fact free of any permeability constraint for sails internal 312 correspondents.
The absence of rigid constraints for the realization tion of the internal sails 312 also makes it possible to provide thin walls-, that is to say of significant thickness-: "

'19 ment lower than that of the outer wall llO qul estquant to it made of a multi-layer material. In particular, a thickness close to 0.8 may be used -mm for radial sails 312, while the outer wall rieure llO will present in practice a neighboring thickness of lmm.
It should also be noted that the two sails internal 312 delimiting passages 311.1 and 311.2 of a hand, and the passage 311.3 on the other hand (that is, ~ say the two sails corresponding to the corner dihedral c) allow a heat exchange for fuel: passage 311.3 borrowed by heated air bubbles and / or fuel (after their passage in the vicinity of the engine) allows indeed to heat the fuel supply coming from the passages 311.1 and 311.2, which is interesting if we _ uses fuels sensitive to low thermal levels (diesel in particular).
~ We will now describe other modes of execution : 'of the invention in the same field of application, according to which the fuel line is arranged for in addition allow the passage of fuel vapors to recover.
The installation of figure 3 thus differs from that of FIG. 1 by the presence of a section of canali-:: ~ 25 station 32 provided for the recovery of ~ fuel fears coming from the tank ~ we find the check valve turning 27 and the vent pipes 28). The lOO pipeline now connects to the three sections 14, 15, 32 by its connector 101, and the three sections 16, 17, 30 26 start from the fitting 102, the section 16 serving as pre ~ demment to the fuel supply to the engine, the section 17 on return of excess fuel, and section 26 serving as previously to channel the vapors of fuel coming from the tank to the recuperator 22 via the non-return valve 24. For the rest, the installation is ._., 212i ~ 241i `

identical to the previous one. Now the vapors of fuel from the tank lO are therefore directed by the section 32 towards the lOl connection, to also penetrate into this pipe 100, to come out of it by the fitting 102 then by section 26, and finally be directed towards the steam recovery unit 22.
In FIGS. 4a and 4b, the line 100 is constituted by an outer tubular wall 110 inside laughing which are arranged three sails 412 s ~ extending radially from the X axis of this outer wall.
The sails 412 and the wall 110 thus delimit three adjoining passages 411.1, 411.2 and 411 ~ 3, which allow channel different flows of fluids, for example two different streams of liquid fuel and a stream of vapors from fuel: passage 411.1 pellt be used to channel - supply fuel, passage 411.2 for return excess fuel to the tank, and passage 411.3 for - recovery of fuel vapors from the - ~ ~ ~ tank. These sails 412 thus define another partition-:
interior, which is made of single-layer material compatible with the ~ fluid concerned.
- In this case, the three sails 412 meet at level of the X axis of the outer wall, but we can variant to leave the sails of a central core more wide, solid or hollow. Furthermore, these three sails 412 here define three dihedrons of the same angle (i.e.
120), so that the three adjoining passages 411.1, 411.2, '411.3 are then of the same section. It goes without saying that may provide a different angular arrangement for these three sails. However, the regular distribution illustrated here has the advantage of imparting mechanical strength to crushing and a bendability which do not depend not the layout of the pipeline.
The outer wall llO is again produced in a multi-layer material, with an internal layer 113 to WO94 / 10491 PCT ~ FR93 / 01060 21262 ~ ~

low permeability to the fluid concerned and an ext ~ rne layer 114 intended to provide mechanical protection and possible also chemical (with possibly between these a layer of adhesive). As before, we illustrated the case particular where it is provided, between layers 113 and 114, an intermediate layer 115 forming a barrier with regard to at least one of the components of this fluid (Figures 4a and 4b) and a layer of adhesive 116 (FIG. 4b), with the same functions benefits and advantages than those mentioned above.
As illustrated here, it is advantageous to provide that the radial sails 412 are integral unita-irely of the inner layer 113 of the outer wall 110, this solidarity resulting for example from coextrusion even of the corresponding profile. These radial sails made of material mono-layer are then advantageously made of polyamide.
Passages 411.1 and 411.2 are both borrowed ted by the same fluid, so that one is actually free any permeability constraint for the radial web 412 corresponding.
We have thus succeeded in considerably reducing the surface changes with the outside: if we compare a conventional set of three independent tubes with a pipeline according to the invention each passage of which has a equivalent passage section, we see that the agency-ment according to the invention reduces by more than 40% the exchange surface.
The absence of rigid constraints for the realization tion of the radial sails 412 also makes it possible to provide thin sails, that is to say of considerable thickness-ment weaker than that of the outer wall llO which estquant to it made of a multilayer material. We will be able to for example use a thickness close to 0.5 mm for each of the radial sails 412, while the outer wall 110 will in practice have a thickness close to 1 mm.

W094 ~ 10491 PCT / FR93 / OtO60 21 '~ 6246 By further choosing an internal diameter close to 10 mm, a pipe is obtained which provides the same flow possibilities as a conventional assembly at three independent tubes with internal diameters and outside are 6 and 8 mm respectively:
exterior is therefore again considerably reduced.
¦ It should also be noted that the veil ¦ intermediate 412 forming a partition between passages 411.1 and ', 411.2 authorizes a heat exchange for the fluid: the j 10 passage 411.2 used here by the air bubbles and / or the heated fuel (after passing near the moteu ~) makes it possible to reheat the fuel of ~
tation.
¦ In FIGS. 4c and 4d, the pipe 100 is ~ ¦ 15 constituted by two tubular walls 110 and 520, which are essentially coaxial and kept at a distance one of the other by 512 spacing fins (Figure 4c) or 522 (Figure 4d ~, here three in number. The two tubular walls-res 110 and 120 are here of circular section, and the wall interior 520 has a transverse internal web 521, which is in this case a diametrical veil passing through the axis X, of - so that this inner wall has two passages contiguous 523, 524 whose sections are identical here, and the outer wall ~ 110 delimited with this inner wall 520 an annular passage 511. The three passages 523, 524, 511 thus delimited allow to channel different flows fluids, e.g. ~ mple here two different fuel flows liquid and a fuel vapor stream from the tank, vapors that can be recovered.
The inner wall 520 with its internal veil transverse 521 and the spacer fins 512 or 522, thus define another interior partitioning which is made of single-layer material compatible with the fluid concerned.
In FIG. 4c, the spacing fins 512 W094 / l0491 PCT / FR93 / 01060 ~, 2 1 2 S 2 4? ~

¦ are integral with the outer wall llO, and extend ¦ radially along the X axis so as to ensure, by their edge ¦ free 512.1, maintaining the interior wall 520. The interior wall 520 is therefore separated from the exterior wall llO, which is interesting when it comes to bending the pipeline. The free edge 512.1 of the fins 512 may be straight, or alternatively have undulations which constitute openings of communication between adjacent annular chambers (here three in number) defined by these fins and constituting the annular passage 511, which then makes it possible to balance the pressures between these bedrooms.
In FIG. 4d, the spacing fins 522 are integral with the inner wall 520, these fins further extending as previously radially along the X axis so as to ensure by their respective free edge ~ 522.1 the maintenance of this inner wall. Such a mode of ! realization is perhaps more delicate in terms of - manufacturing, but a significant advantage is obtained in the extent that all of these spacers can be so r ~ made in a little "noble" material, in particular that used to make the inner wall 520 and the inner sail 521 thereof.
The notion of spacers needs more generally be understood in a broad sense as part of the invention: in particular, provision may be made, at the place ribs extending parallel to the X axis illustrated here, axially interrupted support means, for example in the form of protruding pins or else rings, arranged at predetermined intervals (possibly-chosen according to the particular bending of the . pipeline).
The outer wall llO is again produced in a multi-layer material, with an internal layer 113 to low permeability to the fluid concerned and an outer layer !

212 ~ 2 ~. 24 114 intended to provide mechanical protection and possible also chemical (with possibly between these a adhesive layer). We find here, between layers 113 and 114, a couc ~ e in ~ erm intermediary 115 forming a barrier to viewing at least one of the components of this fluid (Figures 4c and 4d), and a layer of adhesive 116 (FIG. 4d), with the same functions and advantages than before. The outer wall 110, thanks to its multi-layer structure, allows to ensure for line 100 at a time the low fuel permeability, and resistance mechanical and chemical to external aggressions. In addition, the barrier intermediate layer 115 is protected by the adjacent layers, both against attack by fuel vapors (by layer 113) and by fuel liquid (through layer 113 and through the intermediate wall 520) J that against external aggressions, of the mechanical and chemical (by layer 114).
As illustrated in Figure 4c, we may provide that the spacer fins 512 are integral with the inner layer 113 of the wall ext ~ rieure 110, this solidarity resulting advantageously from the same coextrusion of the corresponding profile. These fins 512 will then be made of polyamide.
The inner wall 520 has the sole function of constitute a partition of separation, delimiting by its internal veil 521 the two adjoining passages 523, 524. These two passages ~ 523, 524 are preferably assigned to the ali-statement and return of liquid fuel: said passages are therefore both borrowed by a same fluid, from on both sides of the internal veil 521, so that one is managed to completely free itself from all constraints of permeability for the inner wall 520 of the pipeline The interior wall S20 is also completely protected by the aforementioned outer wall 11O, so that one practically freed from any significant constraint 'WO94 / 10491 PCT / FR93 / 01060 `` 2 ~ .62 ~ fi of mechanical resistance. Therefore, it is possible to ut ~
use less "noble" materials to make the wall interior 520 and the internal veil 521 thereof. He will be in particular possible to use a single-layer material such as polyamide, high density polyethylene, polypropylene, or a recycled material from aforementioned materials.
The absence of rigid constraints for the realization tion of the inner wall 520 and the inner wall 521 of this also makes it possible to provide walls of small thickness, i.e. significantly smaller thickness that of the outer wall llO which is itself made of a multi-layer material. In particular, we may use a thickness of not more than 0.8 mm for the inner wall 520 and its internal veil 521, ~ andis that the outer wall llO will present in practice a thickness close to 1 mm.
¦ Although it is possible to use either passages 511, 523 and 524 for the two fuel streams ! 20 liquid and the fuel vapor stream it will in some cases should be interesting to prefer a passage l ~ more than the other. This is so for example in the case ! where the line 100 is used to connect the r ~
; fuel from a vehicle to the engine of said vehicle, in use sant one of the adjoining passages (for example passage 523) - to channel the supply fuel, and the other adjoining passage (passage 524) for the return of fuel in excess towards the tank, thus reserving the passage ring 511 for fuel vapors from the tank. Indeed, we know that certain fuels (the diesel in particular) are sensitive to low levels thermal: in this case, passage 524 used by heated air bubbles and / or fuel (due to direct vicinity of the motor) provides a protective effect thermal for the passage which is used by the fuel W094 / 1049l PCT / FR93 / 01060 ~ 12624 ~

d feed, which passage is further maintained ~ to distance from the outer wall 110 thanks to the fins 512 spacing. In addition, an accidental shutdown of the Extérieure outer wall 110 does not risk causing a leak 15 liquid fuel, since the inner wall 520 forms a Séparée separate partition containing the liquid.
Regarding the sizing of the pipeline tion, this will in practice be determined according to desired passage sections. So, for example, if we wish to have the same passage sections as with three independent pipes of 6 mm inside diameter, it just choose an inner wall 9 mm in diameter interior and an exterior wall 12.3 mm in diameter interior ~ the interior wall then having a thickness 0.8 mm).
In FIGS. 4e and 4f, the pipe 100 is constituted by an outer tubular wall 110 inside ~
of which two internal walls 620, 630 are arranged distant from each other. The internal walls 620, ~ 30 . 20 delimit, with the outer wall 110, two passages side 621, 631, as well as a central passage 611, the three . passages thus defined making it possible to channel flows different fluids, for example two different flows of liquid fuel as well as a flow of fuel vapors whose recovery is planned.
These two internal walls 620, 630 thus define another interior partitioning, which is made of material '' single layer compatible with the fluid concerned.
The two internal walls can be arranged multiple ways, since the three adjoining passages are delimited and individually present the section desired. We can thus foresee that these internal walls are present in the form of sails which substantially connect perpendicular to the outer wall at their end edges. In this case, the outer wall, which is : - ~ WO94 / 10491 PCT / FR93 ~ 01060 ~ 62 ~ ~

here again made of multi-layer material, presents the same thickness over its entire periphery.
In the present case, another mode of execution has been illustrated.
.tion, according to which each internal wall 620, 630 is connected directly to a partial inner layer respectively 113, 623 of the outer wall 110, so as to form a continuous wall which here has a substantially shaped section circular, the residual parts of this outer wall re, referenced 625 and 635, then forming two canvases of bond which are there also in multi-layer material.
Thus, in Figures 4e and 4f, there are two circular walls, the interior space of which forms each lateral passage 621, 631, these two walls being enveloped laterally (on their half-circumference facing the exterior) by the other layers forming the exterior wall : rieure llO, and being connected by the two connecting fabrics - 625, 635 with which they delimit the central passage 611.
Such an embodiment is not only advantageous for manufacturing, because the pipeline can be produced directly by coextrusion, with perfect watertightness for side passages 621, 631 since there is no has no connection (by thermal welding or the like) likely to be a weakness if worn for : 25 the desired waterproofing! but also for the realization of end fittings (fittings lO1 and lO ~ in Figure 1).
In practice, we will choose two link 625, 635 whose width, noted L, is determined by in such a way that the section of the central passage 611 corresponds ~ 30 to that of a single-pipe pipeline of circular section usually used to recover vapors from fuel. In particular, if one wishes to obtain three passages of the same section, with a section corresponding to the circular section of an individual pipeline of inner diameter D, this value D will be chosen for .

W094 / 1049l PCT / FR93 / 01060 - 212624 ~

two walls defining the lateral passages 621, 631, and a value L close to 1.6 D for the central passage 611.
The outer wall llO is l ~ still made of a multi-layer material, with an internal layer 113 to low permeability to the fluid concerned and an outer layer 114 intended to provide mechanical protection and possible also chemical (with possibly between these a layer of adhesive). We find here, between these layers 113 and 114, an intermediate layer 115 (FIGS. 4e and 4f) forming , 10 barrier to at least one of the components of this ¦fluid, and a layer of adhesive 116 (figure 4f), with the same functions and advantages as before. Wall exterior 110, thanks to its multi-layer structure, allows still ensure for the 100 line both the low fuel permeability, and resistance mechanical and chemical to external aggressions. Here again, the intermediate barrier layer 115 is protected by the adjacent layers, both against attack by the fuel (by layer 113), only against aggressions exterior, mechanical type (by layer 114).
As illustrated in Figures 4e and 4f, each internal wall 620, 630 is integral with the unit of the corresponding partial internal layer 113, 623 of the outer wall 110, this solidarity resulting for example of the same coextrusion of the corresponding profile. These walls interns are then advantageously made of polyamide.
The lateral passages 621, 631 are preferably here borrowed by the fuel (supply and return) and the central passage 611 by the vapors to be recovered.
The absence of rigid constraints for the realization tion of the internal walls 620, 630 also makes it possible to provide thin walls ~ ur, that is to say thick significantly lower than that of the outer wall 11O.
We could for example use an individual thickness close to 0.5 mm for each of the internal walls, while ¦ WO94 ~ 10491 PCT / FR93 / 01060 212S2 ~ "

that the outer wall llO, which here is of essential section bi-circular, will in practice present a thickness close to 1 mm.
Finally, there are other advantages to be mentioned.
appendices in addition to the advantages already mentioned more top: due to the uniqueness of the pipeline, we decrease not only 1 ~ lateral dimensions, but also overall forming possible in a single operation, which both reduces the time and cost of assembly, and also to divide by three the number of fittings required res. We can thus save on weight and on the material cost of around lS%, compared to known assemblies with three independent 6 mm pipes inside diameter. Finally, the pipeline according to the invention lS tion comprising, for comparable flow rates, less plastic than conventional three-piece assemblies independent tubes, we have an additional advantage for the recycling the pipe after use.
The invention is not limited to the embodiments tion which have just been described, but on the contrary encompasses any variant using, with equivalent means, the ~ i essential characteristics ~ not mentioned above.

Claims (25)

1. Fluid pipeline made of material plastic, especially for connecting the fuel tank of a vehicle with the engine of said vehicle, characterized in that that it is constituted by an outer tubular wall (110) made of a multilayer material, said material comprising an internal layer (113) with low permeability to fluid concerned and an outer protective layer (114), and by an internal partitioning (120, 112; 120, 122; 212;
312; 412; 512, 520, 521; 520, 521, 522; 620, 630) arranged inside this outer tubular wall (110) for delimit a plurality of passages, said partitioning being made of a single layer material compatible with ble with said fluid. 2. Pipe according to claim 1, character-laughed at in that the multi-layered material constituting the outer wall (110) further comprises an intermediate layer diary of adhesive between the inner (113) and outer layers (114) of said outer wall. 3. Pipe according to claim 1, character-laughed at in that the multi-layered material constituting the outer wall (110) has an intermediate layer (115) forming a barrier against at least one of the components of the fluid concerned. 4. Pipe according to claim 3, character-laughed at in that the multi-layered material constituting the outer wall (110) further includes a layer of adhesive (116) between the intermediate layer (115) forming a barrier and the outer protective layer (114). 5. Pipe according to claim 3 or the claim 4, characterized in that the inner layers (113) and outer (114) of the outer wall (110) are made of polyamide. 6. Pipe according to one of claims 1 to 5, characterized in that the constituent single-layer material interior partitioning (120, 122; 212; 312; 412; 520, 512, 521; 620, 630) is chosen from the group comprising the polyamides, polyethylene, polypropylene, and recycled materials from the above materials. 7. Pipe according to claim 6, character-laughing at the fact that the single-layer material constituting the interior partitioning (120, 122; 212; 412; 520, 521, 522; 620, 630) additionally includes additional charges, such as a graphite charge to make this partition-interior conductor of electricity. 8. Pipe according to one of claims 1 to 7, characterized in that the interior partitioning (112;
212; 312; 412; 512; 620, 630) is at least partly integral with the inner layer (113) of the wall exterior (110). 9. Pipe according to one of claims 1 to 8, characterized in that the interior partitioning is consisting of an inner tubular wall (120) maintained coaxially in the outer tubular wall (110) by spacing fins (112; 122) which extend radially along the axis (X) common to the two walls, said partitioning and said outer wall thus delimiting a passage central (121) and an annular passage (111) which allow channel two different fluid flows, in particular the fuel supply and return of excess fuel. 10. Pipe according to claim 9, character-in that the outer (110) and inner walls (120) are of circular section, and have respective-a thickness close to 1 mm and 0.5 mm. 11. Pipe according to one of claims 1 to 8, characterized in that the interior partitioning is constituted by a transverse internal veil (212), said partitioning and the outer wall (111) thus delimiting two adjoining passages (211.1; 211.2) which allow channel two different fluid flows, in particular from fuel supply and return of excess fuel. 12. Pipe according to claim 11, characterized in that the internal veil (212) is arranged at a non-zero distance (d) from the axis (X) of the external wall superior (110). 13. Pipe according to claim 12, in which the fluid is a diesel, characterized in that the distance (d) is determined in such a way that the two adjoining passages (211.1, 211.2) respectively present the same section as two single-pipe type pipes usually used for feeding and returning excess diesel, in particular a distance (d) close to 1.5 mm. 14. Pipe according to one of claims 11 to 13, characterized in that the outer wall (110) is of circular section, with a thickness close to 1 mm and an internal diameter close to 10 mm, while the internal veil (212) has a thickness close to 0.8 mm. 15. Pipe according to one of claims 1 to 8, characterized in that the interior partitioning is consisting of three sails (312; 412) extending radially from the axis (X) of the outer wall (110), said partitioning and said outer wall thus delimiting three adjoining passages (311.1, 311.2, 311.3; 411.1, 411.2, 411.3) allowing to channel different flows of fluids, including supply fuel and return excess fuel, and possibly a vapor stream of fuel to recover. 16. Pipe according to claim 15, characterized in that the three sails (312) meet at the axis (X) of the outer wall (110), and define three dihedrons whose angles (a, b, c) are respectively 116 °, 116 ° and 128 ° neighbors. 17. Pipe according to claim 16, in which fluid is diesel, characterized in that the two passages of smaller section (311.1, 311.2) are used for diesel fuel, and the passage of more large section (311.3) for the return of excess diesel, from so as to obtain passages of the same sections as two single-tube type pipes usually used for fuel supply and return. 18. Pipe according to claim 15, characterized in that the three sails (412) meet at the axis (X) of the outer wall (110), and define three dihedrons of the same angle. 19. Pipe according to 1 one of claims 15 to 18, characterized in that the outer wall (110) is of circular section, with a thickness close to 1 mm and an internal diameter close to 10 mm, while the radial sails (312; 412) have a similar thickness from 0.5 to 0.8 mm. 20. Pipe according to one of claims 1 to 8, characterized in that the interior partitioning is constituted by an inner tubular wall (520) with sail transverse internal (521) held coaxially in the outer tubular wall (110) by space fins-ment (512; 522) which extend radially along the axis (X) common to both walls, said partitioning and said wall exterior thus delimiting two adjacent central passages (523, 524) and an annular passage (511) which allow channel different flows of fluids, in particular the supply fuel and excess fuel return, and a flow of fuel vapors to be recovered. 21. Pipe according to claim 20, characterized in that the outer walls (110) and interior (520) are of circular section, and have a thickness close to 1 mm for said outer wall, and at most close to 0.8 mm for said internal wall and its transverse web (521). 22. Pipe according to one of claims 1 to 8, characterized in that the interior partitioning is consisting of two internal walls (620, 630) distant one on the other and delimiting, with the outer tubular wall (110), two side passages (621, 631) and one passage central (611) which allow to channel different flows fluids, including fuel and return of excess fuel, and a vapor flow of fuel to be recovered. 23. Pipe according to claim 22, characterized in that each internal wall (620 to 630) is connects directly to a partial internal layer (113;
623) of the outer wall (110), so as to form a continuous wall having a substantially shaped cross section circular, the residual parts of this outer wall then forming two connecting fabrics (625, 635) which are in multi-layer material. 24. Pipe according to claim 23, characterized in that the two connecting fabrics (625, 635) have a width (L) which is determined in such a way that the section of the central passage (611) corresponds to that of a usual single-section pipe of circular cross-section Also used to recover fuel vapors. 25. Pipe according to claim 23 or the claim 24, characterized in that the outer wall (110) is of essentially bi-circular section and has a minimum thickness close to 1 mm, while the internal walls (620, 630) have a thickness individual close to 0.5 mm.