REINFORCED THERMOPLASTIC PIPE

Abstract

A pipe intended to be mounted in a fluid circuit of an aircraft, the pipe comprising a tube and two connection ends, the tube being made of a thermoplastic material and having a cylindrical shape, the tube defining an internal surface, intended to be in contact with the fluid, and an external surface opposite the internal surface, the pipe comprising at least one reinforcement band extending longitudinally on the external surface of a longitudinal portion of the tube, so as to form a reinforced portion of the tube.

Claims

1-8. (canceled)

9. A method of manufacturing a pipe intended to be mounted in a fluid circuit of an aircraft, the pipe comprising a tube and two connection ends, the tube being made of thermoplastic material and having a cylindrical shape, the tube defining an internal surface, intended to be in contact with the fluid, and an external surface opposite the internal surface, the manufacturing method, comprising: a step of determining at least two portions to be reinforced of the tube, a step of determining at least one portion to be bent, the portion to be bent being positioned between the at least two portions to be reinforced, a step of positioning at least one reinforcement band extending longitudinally over the external surface of the at least two portions to be reinforced, the portion to be bent being free of the reinforcement band, then a step of bending the portion to be bent.

10. The method of manufacturing according to claim 9, wherein the reinforcement band comprises reinforcement fibers impregnated with a thermoplastic resin.

11. The method of manufacturing according to claim 10, wherein the thermoplastic resin of the reinforcement band is identical to the thermoplastic material of the tube.

12. The method of manufacturing according to claim 11, wherein the thermoplastic resin of the reinforcement band and the tube is polyaryletherketone.

13. The method of manufacturing according to claim 10, wherein the reinforcement fibers are unidirectional fibers.

14. The method of manufacturing according to claim 9, wherein, in a cross-sectional plane, the reinforcement band(s) extend over an angular range of between 28 and 58 at the periphery of the reinforced portion.

15. The method of manufacturing according to claim 9, wherein the reinforced portion comprises at least three reinforcement bands distributed angularly over the external surface of the reinforced portion and positioned equidistant from each other.

16. The method of manufacturing according to claim 9, wherein the reinforcement band has a thickness of between 0.1 and 0.4 mm.

17. A method of manufacturing a pipe for use on an aircraft, the pipe comprising a thermoplastic cylindrical tube section having two connection ends, the tube section having an internal surface and an external surface opposite the internal surface, the manufacturing method, comprising: positioning one or more reinforcement bands over the external surface of the tube section at two spaced apart portions of the tube section to define two spaced apart portions of the tube section to be reinforced in a positioning step; bending a portion of the tube section at a location between the two spaced apart portions of the tube section to be reinforced to define a bent section in a bending step; and wherein the bent section is free of the one or more reinforcement bands and is formed after the positioning step.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The invention will be better understood upon reading the following description, given as an example, and by referring to the following figures, given as non-limiting examples, wherein identical references are given to similar objects.

[0045] FIG. 1 is a schematic representation of a pipe intended to be mounted in a fluid system.

[0046] FIG. 2 is a schematic representation of a reinforced pipe according to a first embodiment of the invention.

[0047] FIG. 3 is a schematic representation of a cross-sectional view of the reinforced pipe of FIG. 2.

[0048] FIG. 4 is a cross-sectional view of a reinforced pipe according to a second embodiment of the invention.

[0049] FIG. 5 is a schematic representation of a reinforcement band intended to be mounted on the reinforced pipe according to the invention.

[0050] FIG. 6 is a cross-sectional view of the reinforcement band in FIG. 5.

[0051] FIG. 7 is a schematic representation of the steps of a method for manufacturing a reinforced pipe according to an embodiment of the invention.

[0052] FIG. 8 is a schematic representation of the step of simultaneously attaching a plurality of reinforcement bands onto a thermoplastic tube.

[0053] FIG. 9 is a cross-sectional view of the step of simultaneously attaching the plurality of reinforcement bands to the thermoplastic tube.

[0054] It should be noted that the figures set out the invention in detail in order to implement the invention, said figures may of course be used to better define the invention if necessary.

DETAILED DESCRIPTION

[0055] The invention relates to a pipe intended to be mounted in a fluid circuit of an aircraft, for example a drinking water circuit. As described previously, a fluid circuit comprises a plurality of pipes mechanically and fluidically connected to each other and wherein a fluid circulates.

[0056] As previously described, each pipe 1 has a predetermined profile to follow for example the curvatures of the aircraft structure or bypass equipment. To do this, each pipe 1 may be bent locally. Also, in this application, distinguished are an initial state of the pipe 1 before bending, i.e. the pipe 1 extends longitudinally over its entire length, and a final state after bending, i.e. a state wherein the pipe 1 has one or more curved portions.

[0057] In the initial state, shown in FIG. 1, the pipe 1 extends longitudinally along an X axis, transversely along an axis Y and vertically along an axis Z, so as to form a system of coordinates (X, Y, Z).

[0058] Each pipe 1 comprises a tube 2 and two connection ends 3. It goes without saying that the tube 2 comprising two connection ends 3 may be part of an assembly comprising one or more connection fittings, as is known. The connection ends are in themselves known to those skilled in the art, so they will not be further described in this document.

[0059] The tube 2 has a cylindrical shape and defines an internal surface SI, intended to be in contact with the fluid, and an external surface SE opposite the internal surface SI (FIGS. 3 and 4). Preferably, the section is circular.

[0060] According to the invention, the tube 2 is made of a thermoplastic material, i.e. it is entirely made of thermoplastic material, allowing the use of a light material. In other words, the tube 2 does not comprise any reinforcing fibers in the thickness of its wall. Preferably, the tube 2 is made of polyaryletherketones (PAEK). It goes without saying that tube 2 may be made of a different thermoplastic resin, for example polyetherimide (PEI).

[0061] Still in reference to FIG. 1, the tube 2 preferably has a length L2 of between 500 and 3000 mm in the initial state. The tube 2 also has a thickness Ep2 (shown in FIG. 3) preferably between 0.8 and 1.3 mm. The pipe 1 is therefore light and easy to handle when installed in a fluid circuit.

[0062] As shown in FIG. 1, the tube 2 according to the invention comprises one or more portions known as portion to be reinforced 21. In this example, the tube 2 comprises two portions to be reinforced 21A, 21B, extending longitudinally along a U-portion axis. When the pipe 1 is in the initial state, the U-portion axis is confounded with the longitudinal axis X.

[0063] In this example, the tube 2 also comprises a portion known as a portion to be bent 22. Preferably, the portion to be bent 22 is positioned between the two portions to be reinforced 21A, 21B, as shown in FIG. 1. Such a portion to be bent 22 corresponds to a portion of the tube 2 which is not to be reinforced and more precisely which must not be reinforced, as will be described in more detail later.

[0064] Preferably, the tube 2 comprises a plurality of portions not to be reinforced. In particular, the portions not to be reinforced correspond to the portions to be bent 22 and the end portions 23, intended to be connected to a connection end 3. This document presents the example of a tube 2 of pipe 1 comprising two portions to be reinforced 21A, 21B and a portion to be bent 22. However, it goes without saying that the tube 2 may comprise a different number of portions to be reinforced 21 and portions to be bent 22.

[0065] FIG. 2 shows a tube 2 in its final state. In this state, the tube 2 comprises two reinforced portions 4A, 4B (corresponding to the two portions to be reinforced 21A, 21B of the initial state), each extending along an axis of portion UA, UB, and a bent portion 5 (corresponding to the portion to be bent 22 of the initial state), positioned between the two reinforced portions 4A, 4B. In other words, the portions to be reinforced 21A, 21B make it possible to form in the final state the reinforced portions 4A, 4B and the portion to be bent 22 makes it possible to form in the final state the bent portion 5.

[0066] In reference to FIG. 2, the pipe 1 according to the invention comprises one or more reinforcement bands 6 extending longitudinally on the external surface SE of each portion to be reinforced 21A, 21B of the tube 2, so as to ultimately form a reinforced portion 4, as will be presented in more detail later. Subsequently, the term portion to be reinforced 21A, 21B refers to the portions of tube 2 intended to receive one or more reinforcement bands 6, and the term reinforced portion 4 refers to the portions of tube 2 to which reinforcement bands 6 are applied.

[0067] Preferably, the pipe 1 comprises at least one reinforcement band 6 on each reinforced portion 4 of tube 2. Preferably, the reinforced portions 4 of a same tube 2 are associated with the same number of reinforcement bands 6.

[0068] In a first embodiment, in reference to FIG. 3, representing a cross-sectional view of the pipe 1, the latter comprises three reinforcement bands 6 on each reinforced portion 4, the three reinforcement bands 6 being distributed angularly on the external surface SE of the tube 2 and being positioned equidistant from each other. In a second preferred embodiment, shown in FIG. 4, the pipe 1 comprises four reinforcement bands 6 on each reinforced portion 4, the four reinforcement bands 6 being distributed angularly on the external surface SE of the tube 2 and being positioned equidistant from each other.

[0069] It goes without saying that the number of reinforcement bands 6 could be different, it is preferably even. In addition, the reinforcement bands 6 are preferably arranged symmetrically in order to limit buckling in two opposite directions.

[0070] In a preferred embodiment, each reinforcement band 6 extends, in a cross-sectional plane (Y, Z), over an angular range a ranging from 28 to 58, shown in FIG. 4. Such an angular range a depends on the radius of the tube 2. In other words, each reinforcement band 6 preferably extends over an angular perimeter A6 of between 31% and 64% of the external perimeter of the tube 2.

[0071] In reference to FIGS. 5 and 6, each reinforcement band 6 extends longitudinally along an axis I, transversely along an axis J and vertically along an axis K, so as to form a system of coordinates (I, J, K). When the reinforcement band 6 is positioned on the external surface SE of the tube 2, the longitudinal axis I of the reinforcement band 6 is confounded with the longitudinal axis X of the pipe 1.

[0072] Each reinforcement band 6 has a lower surface 63, intended to be in contact with the external surface SE of the tube 2, and an upper surface 64 opposite the lower surface 63.

[0073] In a preferred embodiment, each reinforcement band 6 comprises reinforcement fibers 61 impregnated with a thermoplastic resin 62. Preferably, the thermoplastic resin 62 of the reinforcement band 6 is identical to the thermoplastic material of the tube 2, so as to allow effective and homogeneous attachment between each portion to be reinforced 21A, 21B of the tube 2 and the reinforcement band 6. The thermoplastic resin 62 of the reinforcement band 6 is preferably polyaryletherketone (PAEK). It goes without saying that the reinforcement band 6 may be made of a different thermoplastic resin, e.g. polyetherimide (PEI) compatible with polyaryletherketone (PAEK).

[0074] Each reinforcement band 6 is configured to be attached to the external surface SE of the tube 2 preferably by welding bonding. Such a bonding method is known per se for joining thermoplastic parts. It goes without saying that the reinforcement bands 6 may be mechanically connected to the external surface SE of the tube 2 by any other means, for example, by applying adhesive.

[0075] Preferably, the reinforcement fibers 61 are unidirectional fibers extending longitudinally along the axis I, as shown in FIG. 5. Such unidirectional fibers are advantageous for reducing buckling according to the direction of said fibers. In addition, the reinforcing fibers 61 are preferably glass fibers, carbon or aramid fibers. Alternatively, each reinforcement band 6 may comprise a stack of several layers of unidirectional reinforcement fibers 61 to enable even greater reinforcement of the tube 2.

[0076] In this example, still in reference to FIGS. 5 and 6, each reinforcement band 6 has a width L6 along the axis J of between of an inch, i.e. 3.2 mm and of an inch, i.e. 12.7 mm. Preferably, such a width L6 is substantially equal to inch (6.35 mm), so as to cover 31%, 43% or 64% of the external surface SE of the tube 2, respectively for a tube with a diameter of 1 inch (25.4 mm), inch (19.05 mm) or inch (12.7 mm). Each reinforcement band 6 also has a length M6 along the axis I previously defined according to the length of the portion to be reinforced 21A, 21B to which the reinforcement band 6 is intended to be applied. The length M6 is thus preferably between 450 and 700 mm, so as to apply a reinforcement band 6 over the entire length of each portion to be reinforced 21A, 21B. Preferably, the reinforcement band 6 is packaged in rolls and cut to the desired length.

[0077] Preferably, each reinforcement band 6 has a thickness Ep6 of between 0.1 and 0.4 mm. Such a thickness Ep6 of the reinforcement band 6 limits the increase in the total thickness of the tube 2, which prevents any impact on the production chain of the pipes 1, by allowing the use of machines known and already used in this field. In other words, even with one or more reinforcement bands 6 deposited on the external surface SE of tube 2, the latter may be mounted in machines of the existing production line and in particular in existing bending machines. In summary, each reinforced portion 4 has a thickness close to the thickness of the non-reinforced portions, which makes it possible not to impact the industrial manufacturing process of the pipe 1.

[0078] A method for manufacturing a pipe 1 according to an embodiment of the invention, in reference to FIGS. 7 to 9, will now be described. At the beginning of the manufacturing method, the pipe 1 is initially in its initial state, shown in FIG. 1 and wherein the tube 2 extends fully along the longitudinal axis X.

[0079] The method first comprises a step of determining E1 of one or more portions to be reinforced 21 of the tube 2. Preferably, the operator also determines, in a second step of determining E2, one or more portions to be bent 22 of the tube 2. In this example, the operator determines two portions to be reinforced 21A, 21B and a portion to be bent 22, the portion to be bent 22 being positioned between the two portions to be reinforced 21A, 21B, as shown in FIG. 1.

[0080] In this example, the operator then positions, in a step of positioning E3, four reinforcement bands 6 on the external surface SE of the first portion to be reinforced 21A of the tube 2. The reinforcement bands 6 are positioned so as to be distributed angularly over the external surface SE of the tube 2, being positioned equidistant from each other, as shown in FIG. 4. It goes without saying that the number of reinforcement bands 6 positioned on the external surface SE of the tube 2 could be different. The operation is then repeated for the positioning in this example of four reinforcement bands 6 on the external surface SE of the second portion to be reinforced 21B. In this step, no reinforcement band 6 is positioned on the external surface SE of the portion to be bent 22, which is then only made of thermoplastic material.

[0081] In a preferred embodiment, the operator then places, in a step of positioning E4, four pressure members R on the external surface SE of the tube 2. The four pressure members R are preferably distributed angularly at the periphery of the tube 2, equidistant from each other. More preferably, as shown in FIGS. 8 and 9, the four pressure members R are positioned at the periphery of the tube 2 so as to be centered on each reinforcement band 6, allowing effective and optimal application of the reinforcement bands 6. This document presents the example of four pressure members R, however, it goes without saying that the number of pressure members R may be different, as long as the pressure members R are evenly distributed at the periphery of the tube 2, so as to ensure uniform pressure over the periphery of the tube 2 and thus avoid any deformation of the tube 2, as described in more detail below.

[0082] In this example, each pressure member R has the form of a roller which rotates about an axis V (shown in FIG. 9) and which moves along the longitudinal axis X of the tube 2, to enable the reinforcement bands 6 to be applied along their entire length M6. It goes without saying that each pressure member R in the form of a roller could also be fixed.

[0083] The method then preferably comprises a simultaneous step of heating E5 by a heating device S (shown in FIG. 8) of the external surface SE of the first portion to be reinforced 21A of the tube 2 and the lower surface 63 of each reinforcement band 6, so as to allow bonding welding of the reinforcement band 6 on the first portion to be reinforced 21A to form the first reinforced portion 4A. It goes without saying that in this step of heating E5, only the external surface SE of the tube 2 or only the lower surface 63 of each reinforcement band 6 could be heated. By way of example, the heating device S may be of the radiative (e.g. infrared, laser), conductive (heating wire), convective (hot air), inductive or mechanical (ultrasonic friction) type.

[0084] In a step of applying E6, each pressure member R then simultaneously applies an identical radial pressure force P to the upper surface 64 of each reinforcement band 6 positioned on the external surface SE of the first portion to be reinforced 21A of the tube 2, as shown in FIGS. 8 and 9. Such a step makes it possible to deposit all the reinforcement bands 6 at the same time. The distribution of the pressure members R and the application of the same pressure force P allow uniform application of pressure to the periphery of the tube 2, so as to avoid any risk of deformation of the tube 2. The steps of heating E5 and applying E6 of a force allow assembly by welding of the reinforcement bands 6 onto the tube 2.

[0085] Preferably, in these two steps of heating E5 and of applying E6 a pressure force P, the heating device S and the pressure members R move successively and progressively along the longitudinal axis X of the tube 2, as shown in FIG. 8, so as to gradually deposit the reinforcement bands 6 along the entire length of the first portion to be reinforced 21A. This document shows an example of a fixed tube 2 along which the pressure members R are moved in the form of rollers; however, it goes without saying that each pressure member R, as well as the heating device S, could also be fixed. The tube 2 would then move longitudinally along its axis X in order to deposit the reinforcement bands 6 along the entire length of the first portion to be reinforced 21A in a similar way to the steps of heating E5 and of applying E6 described previously.

[0086] The reinforcement bands 6 are thus attached to the external surface SE of the first portion to be reinforced 21A of the tube 2, thus forming the first reinforced portion 4A, shown in FIG. 2. The steps of heating E5 and applying E6 a pressure force P are then repeated for the second portion to be reinforced 21B, so as to form the second reinforced portion 4B.

[0087] The manufacturing method then comprises a step of bending E7 the portion to be bent 22, so as to form the bent portion 5. Thanks to the prior determination of the portions to be reinforced 21 and the portions to be bent 22 and the thin thickness and material of the reinforcement bands 6, this bending step E7 may easily be carried out by known and commonly used production machines. No fibers are bent, which is advantageous.

[0088] Thanks to the reinforcement according to the invention, the production chain of the pipe is not impacted and the pipe is locally reinforced, which allows it to resist buckling.