Fluid circuit comprising a connecting fitting for double-walled pipes and associated method

Abstract

A fluid circuit (CF), in particular for an aircraft, comprising a connecting connector (3) made of thermoplastic material, for sealingly connecting two pipes (A, B), the connecting connector (3) comprising: an inner connecting conduit (33) configured to fluidically connect a tube (TA) of the first pipe (A) and an inner tube (TI-B) of the second pipe (B), and a single-piece outer connecting conduit (34) configured to cooperate with an outer tube (TE-B) of the second pipe (B), the inner connecting conduit (33) being trapped in the outer connecting conduit (34) and being mounted at a determined position in the outer connecting conduit (34) to allow a connection of the inner connecting conduit (33) with the inner tube (TI-B) of the second pipe (B) in a blind manner during the connection of the outer connecting conduit (34) with the outer tube (TE-B) of the second pipe (B).Abstract Figure: Figure 4.

Description

Title of the invention: Fluid circuit comprising a connecting fitting for double-walled pipes and associated method Technical field

[0001] The present invention relates to the field of fluid circuits in an aircraft, for example, a drinking water circuit, waste water, drainage, etc. The invention relates in particular to the connection of pipes of such a fluid circuit.

[0002] In a known manner, a fluid circuit comprises a plurality of pipes mechanically and fluidically connected to each other. When installing a fluid circuit in an aircraft, the pipes are independently secured to the structure of the aircraft and then fluidically connected to each other. To connect a first pipe to a second pipe, it is known to use a connecting fitting which must be mounted at the interface between the first pipe and the second pipe in order to ensure a sealed connection. Connecting fittings which allow three pipes to be connected and which are known under the name "T-fitting" are also known.

[0003] In order to reduce the weight of an aircraft, pipes are increasingly manufactured from a thermoplastic material, and more particularly from a polymer known under the designation PEEK (meaning polyetheretherketone), which allows the manufacture of semi-rigid, light and robust pipes. Such a pipe also has a low thickness.

[0004] In practice, in an aircraft, the drinking water circuit is mounted in the structure of the aircraft and may pass through areas comprising electrical devices. To avoid any risk of water leaking into the electrical network, it is necessary for the pipes to be doubled. Such a pipe is commonly referred to as a "double-walled pipe" and as such comprises an outer tube and an inner tube mounted in the outer tube.

[0005] With reference to [Fig. 1], a connecting connector 101 is known in the prior art which makes it possible to connect a first double-walled pipe A to a second double-walled pipe B, each being made of thermoplastic material. Such a connecting connector 101 comprises a connecting member 102 which connects the inner tubes TI of the two pipes A, B and an outer casing 103 which connects the outer tubes TE and makes it possible to guarantee sealing in the event of a leak in the connecting member 102. [Fig. 2] similarly shows the connection of three pipes A, B, C by means of a T-shaped connecting connector 101 of the prior art. a significant mass. It is equipped with several clasps 104 which must be manipulated by the operator during closing. In practice, to ensure the tightness of the connection, the connecting member 102 must be firmly locked, which requires the application of a significant tightening torque to each clasp 104 using tools, which increases the difficulty for operators. In addition, the use of tools is impractical, particularly in an aircraft fluid circuit which may require several hundred connecting fittings. In addition, handling tools presents a risk for the operator who is working in a confined space.

[0007] Furthermore, as described above, to ensure the sealing of the connecting connector 101, an outer casing 103 is added and makes it possible to connect the outer tubes TE of the pipes A, B. Such an outer casing 103 comprises two half-shells which are sealed by means of resin, which again has the disadvantage of being time-consuming and complex to implement. In addition, the outer casing 103 significantly increases the size of the connecting connector 101, which is not desirable in an aircraft in which space is limited and each connection is difficult to access.

[0008] In summary, the installation of the connecting fitting is time-consuming, impractical and increases the cost of installing a fluid circuit. There is currently no lightweight and space-saving connecting fitting that allows the connection of double-walled pipes made of a thermoplastic material.

[0009] The invention thus aims to eliminate at least some of these drawbacks by proposing a lightweight and space-saving connecting fitting, which makes it possible to connect two double-walled pipes made of thermoplastic material in a simple, rapid and practical manner. The invention aims in particular at the connection of at least two thermoplastic pipes, at least one of which is a double-walled pipe. PRESENTATION OF THE INVENTION

[0010] The invention relates to a fluid circuit, in particular for an aircraft, comprising: • at least one first pipe made of thermoplastic material comprising a connection end comprising a connector, hereinafter “first connector”, the first pipe comprising at least one tube, • at least one second pipe made of thermoplastic material comprising a connection end comprising a connector, hereinafter “second connector”, the second pipe comprising an outer tube and an inner tube mounted in the outer tube, the first pipe and the second pipe extending along a longitudinal axis, and • a connecting fitting made of thermoplastic material, for sealingly connecting the two connection ends, comprising: • at least one first connection end configured to be mechanically connected to the first connector, • at least one second connection end configured to be mechanically connected to the second connector, • an internal connecting conduit configured to fluidically connect at least the tube of the first pipeline and the internal tube of the second pipeline, • an external connecting conduit configured to cooperate with at least the external tube of the second pipeline, the external connecting conduit being in one piece, • the inner connecting conduit being trapped in the outer connecting conduit so as to prevent any separation of the inner connecting conduit and the outer connecting conduit, the inner connecting conduit being mounted at a determined position in the outer connecting conduit so as to allow a connection of the inner connecting conduit with at least the inner tube of the second pipe in a blind manner when connecting the outer connecting conduit with at least the outer tube of the second pipe.

[0011] By the expression "imprisoned" is meant that the inner conduit is mounted in the outer conduit in a captive manner. In other words, the inner connecting conduit and the outer connecting conduit are inseparable.

[0012] The connecting fitting according to the invention makes it possible to connect two pipes made of thermoplastic material, at least one of which is a double-walled pipe, in a simple and practical manner. The inner and outer tubes of the double-walled pipe can be connected simultaneously to the connecting fitting, allowing blind connection of the inner connecting conduit of the connecting fitting with the inner tube of the pipe when connecting the outer connecting conduit with the outer tube of the pipe, which are visible to the operator. In other words, unlike the prior art, it is not necessary to connect the inner conduits and the outer conduits successively and independently, which allows a significant saving of time. This is particularly advantageous in a fluid circuit of an aircraft which comprises a large number of connecting fittings.

[0013] A single-piece connecting fitting comprising an inner connecting conduit and an outer connecting conduit secured to each other is advantageously space-saving, also allowing a single part to be stored and handled, which is practical.

[0014] The thermoplastic material connection fitting has the advantage of being light and easily handled by an operator. In addition, a thermoplastic fitting can easily be fixed manually by an operator without requiring special tools, which limits its arduousness. This also presents a significant advantage in an aircraft, in which space is limited and connection fittings are often difficult to access. In addition, its cost is significantly reduced, which is advantageous.

[0015] In one embodiment, the fluid circuit comprises at least one spacer mounted between the inner connecting conduit and the outer connecting conduit, so as to connect them mechanically, the connecting fitting forming a single-piece assembly. The spacer makes it possible to precisely position the connecting ends of the connecting member opposite the tubes of each pipe, without the inner connecting conduit risking moving in the outer connecting conduit. In other words, the spacer makes it possible to place the inner connecting conduit at a predetermined relative position with respect to the outer connecting conduit, which allows the simultaneous connection of the inner tube and the outer tube of a double-walled pipe.

[0016] Preferably, the fluid circuit comprises a plurality of spacers mounted between the inner connecting conduit and the outer connecting conduit, the spacers of the plurality of spacers being distributed around the inner connecting conduit to allow stable and balanced support.

[0017] Preferably, the connecting fitting is made of a thermoplastic material chosen from: polyetheretherketone and polyamides filled with glass fibers, which allows a connecting fitting for double-walled pipes that is lightweight and which limits the strain on operators. Preferably, the connecting fitting is made of polyetheretherketone or a polyamide filled with 30% glass fibers, allowing a connecting fitting that is both lightweight and robust.

[0018] In one embodiment, the tube of the first pipeline being an inner tube, the first pipeline comprising an outer tube, the inner tube being mounted in the outer tube, the inner connecting conduit of the connecting fitting is configured to fluidly connect the inner tube of the first pipeline and the inner tube of the second pipeline, and the outer connecting conduit is configured to connect the outer tube of the first pipeline and the outer tube of the second pipeline.The connecting fitting can thus advantageously connect two double-walled pipes simply and quickly by allowing both a simultaneous connection of the inner connecting pipe and the outer connecting pipe respectively with the inner tube and the outer tube of the first pipe and a simultaneous connection of the inner connecting pipe and the outer connecting pipe respectively with the inner tube and the outer tube of the second pipe. In summary, the connecting fitting allows two double-walled pipes to be connected in . thermoplastic material in a simple and practical way.

[0019] In one embodiment, the fluid circuit comprising a third pipe made of thermoplastic material extending along a lateral axis orthogonal to the longitudinal axis, the third pipe comprising at least one tube, the third pipe comprising a connection end comprising a connector, hereinafter "third connector", the connecting fitting comprises a third connection end configured to be mechanically connected to the third connector, the inner connecting conduit being configured to fluidically connect the tube of the first pipe, the inner tube of the second pipe and the tube of the third pipe. The connecting fitting makes it possible to connect three pipes of which only one, two or all three pipes are double-walled pipes made of thermoplastic material in a simple and practical manner.In the case of the connection of three double-walled pipes, the inner connecting pipe and the outer connecting pipe are advantageously connected simultaneously respectively to the inner tube and to the outer tube of each pipe.

[0020] Preferably, the inner connecting conduit and the outer connecting conduit have a "T" shape in which the inner connecting conduit is trapped in the outer connecting conduit. The connection of three thermoplastic pipes can be carried out in a practical manner and the connection can be easily put in place in a fluid circuit of an aircraft whose environment is cluttered.

[0021] The invention also relates to an aircraft comprising at least one fluid circuit as described previously.

[0022] Finally, the invention relates to a method for connecting at least a first pipe and a thermoplastic material connecting fitting of a fluid circuit as described previously, the method comprising at least the steps of: • connecting the external connecting conduit of the connecting fitting with at least the external tube of the second pipe, and • simultaneously, blindly connect the inner connecting pipe with at least the inner tube of the second pipe. PRESENTATION OF FIGURES

[0023] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0024] [Fig.l] is a schematic representation of a connecting fitting according to the prior art for connecting two pipes.

[0025] [Fig. 2] is a schematic representation of a connecting fitting according to the art previous for the connection of three pipes.

[0026] [Fig. 3] is a schematic representation in exploded view of a fluid circuit according to one embodiment of the invention.

[0027] [Fig.4] is a sectional view of a schematic representation of a connecting fitting according to one embodiment of the invention for connecting a single-walled pipeline and a double-walled pipeline.

[0028] [Fig.5] is a sectional view of a schematic representation of a connecting fitting according to one embodiment of the invention for connecting two double-walled pipes.

[0029] [Fig.6] is a schematic representation of a connecting fitting according to one embodiment of the invention for connecting three double-walled pipes.

[0030] [Fig.7] is a close-up sectional view of the connecting fitting of [Fig.6].

[0031] [Fig.8] is a diagram of the steps of a method of connecting two pipes according to an embodiment of the invention.

[0032] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0033] A fluid circuit according to the invention will be presented, intended to be mounted in an aircraft, in particular for the transport of water, however it goes without saying that the fluid circuit could just as easily allow the transport of a different fluid, such as fuel or gases.

[0034] As is known, a fluid circuit comprises a plurality of pipes which are connected to each other in order to guide a fluid. The invention will be presented initially for the connection of two pipes of a fluid circuit. However, the invention also applies to the connection of more than two pipes, as will be described later.

[0035] With reference to [Fig. 3], there is shown an exploded view of a fluid circuit CF according to one embodiment of the invention. The fluid circuit CF comprises a first pipe A, a second pipe B, mounted opposite each other, and a connecting connector 3, intended to be mounted at the interface between the first pipe A and the second pipe B, in order to fluidically connect them.

[0036] In this example, the first pipe A and the second pipe B extend longitudinally along an X axis, laterally along a Y axis and vertically along a Z axis, so as to form an orthogonal reference frame (X, Y, Z). Also, the term "vertical" describes an object extending in the (Y, Z) plane and the term "horizontal" means an object that extends in the (X, Y) plane. Similarly, the terms "front" and "back" refer to the longitudinal axis X that extends from the first pipe A to the second pipe B from back to front, according to the direction of flow of a fluid from back to front.

[0037] According to one aspect of the invention, the first pipe A and the second pipe B are made of a thermoplastic polymer material. In this example, each pipe A, B is preferably made of polyetheretherketone, commonly referred to by the acronym PEEK (meaning PolyEtherEtherKetone in English).

[0038] With reference to [Fig. 4], showing a longitudinal sectional view of the assembled fluid circuit CF, the first pipe A comprises, in this example, a tube TA, forming a single-walled pipe. The second pipe B comprises an outer tube TE-B and an inner tube TLB, mounted in the outer tube TE-B. The inner tube TLB and the outer tube TE-B are concentric and form a double-walled pipe. Each tube TA, TE-B, TLB extends along the longitudinal axis X. A first example is described in which the first pipe A is a single-walled pipe. In a second embodiment shown in [Fig. 5], the first pipe A also comprises an outer tube TE-A and an inner tube TLA mounted in the outer tube TE-A, the inner tube TLA and the outer tube TE-A of the first pipe A being concentric and forming a double-walled pipe.In other words, the connecting connector 3 according to the invention makes it possible to connect at least two pipes A, B, at least one of which is a double-walled pipe.

[0039] In this example, each tube TA, TE-B, TLB has a cylindrical shape. Preferably, the tubes TA, TE-B, TLB have the shape of a right circular cylinder, as shown in the figures. However, it goes without saying that the tubes may have a different shape, for example the shape of a cylinder with a square or rectangular base. Each tube TA, TE-B, TLB comprises a cylindrical inner surface which extends radially inwardly of said tube TA, TE-B, TLB and a cylindrical outer surface which extends radially outwardly of the tube TA, TE-B, TLB. In this example, the inner surface of the inner tube TLB of the second pipe B and the inner surface of the tube TA of the first pipe A are intended to come into contact with the fluid.

[0040] As shown in [Fig.4], to allow the connection, the inner tube TI of each double-walled pipe A, B has a length along the longitudinal axis X greater than the length of the outer tube TE.

[0041] In this embodiment, each pipe A, B has a connection end Al, Bl. The two connection ends Al, B1 are intended to be connected via the connecting connector 3. More specifically, as shown in Figures 3 and 4, each connection end A1, B1 comprises a connector 1, 2 which cooperates with the connecting connector 3. Subsequently, for the sake of clarity, the connector 1 mounted on the connection end A1 of the first pipe A will be designated “first connector” 1 and the connector 2 mounted on the connection end B1 of the second pipe B will be designated “second connector” 2.

[0042] Still with reference to Figures 3 and 4, each connector 1, 2 has a tubular shape and is configured to cooperate by complementarity of shapes respectively with each pipe A, B. In this example, each connector 1, 2 cooperates respectively with the outer surface of the tube TA of the first pipe A and with the outer surface of the outer tube TE-B of the second pipe B. In practice, each connector 1, 2 has dimensions adapted to cooperate with the pipe on which it is mounted. In other words, the first connector 1 and the second connector 2 have similar shapes with a diameter adapted to fit on the connection end A1, B1 of a single-wall pipe or a double-wall pipe.

[0043] In this respect, in this example, the first connector 1 mounted on the single tube TA of the first pipe A has a diameter DI smaller than the diameter D2 of the second connector 2 mounted on the outer tube TB of the second pipe B. In the case of the connection of two double-walled pipes A, B, the two connectors 1, 2 are identical to the second connector 2, as shown in [Fig. 5]. The two connectors 1, 2 then preferably have identical dimensions.

[0044] In particular, each connector 1, 2 comprises a fitting portion 11, 21, mounted on the connection end A1, B1 and a connecting portion 12, 22 configured to cooperate with the connecting connector 3. The connecting portion 12, 22 is configured to cooperate with the connecting connector 3 for example by fitting. In this example, the connecting portion 12 has an external radial diameter D12 shown in [Fig.4].

[0045] With reference to Figures 3 and 4, each connector 1, 2 comprises, in this example, a connection collar 13, 23, which extends in radial projection from the connecting portion 12, 22. The connection collar 13, 23 is configured to allow a connection with the connecting connector 3, as will be described in more detail later. In this example, the connection collars 13, 23 have a diameter De.

[0046] Preferably, each connector 1, 2 comprises on the connecting portion 12, 22 a radial groove 15, 25 for receiving a sealing gasket J (shown in [Fig.4]), configured to be sandwiched between the connector 1, 2 and the connection of connection 3, so as to limit any risk of leakage in the connection.

[0047] To connect each pipe A, B to the connecting fitting 3, each connector 1, 2 comprises a locking member 5 and a securing member 6.

[0048] The locking member 5 is configured to perform axial locking along the longitudinal axis X of the connector 1, 2 and the connecting fitting 3 relative to the connection end A1, B1 of the pipe A, B. In this example, the locking member 5 is configured to lock the connector 1, 2 and the connecting fitting 3 by clipping, as will be described in more detail later. It goes without saying that the locking could be performed in a different manner, for example by screwing.

[0049] The securing member 6 is configured to prevent any removal of the locking member 5 and thus avoid any untimely disconnection of the connecting fitting 3 and the pipe A, B. In this example, the securing member 6 is configured to be connected to the locking member 5 by clipping to allow a simple and rapid connection. It goes without saying that the securing of the connection could be carried out in a different way, for example by screwing.

[0050] As described previously, the connecting connector 3 makes it possible to connect in a sealed manner the connection end A1 of the first pipe A via the first connector 1 and the connection end B1 of the second pipe B via the second connector 2.

[0051] According to one aspect of the invention, the connecting connector 3 is made of a thermoplastic material, which makes it possible to limit its mass and its cost. In particular, the connecting connector 3 is preferably made of polyetheretherketone, commonly designated by the acronym PEEK (meaning PolyEtherEtherKetone in English). Such a PEEK material is a thermostable semi-crystalline thermoplastic having high mechanical characteristics and resistant to high temperatures. Alternatively, the connecting connector 3 is made of polyamide filled with glass fibers and in particular of polyamide filled with 30% glass fibers.

[0052] As described above, [Fig.4] shows a sectional view of the connecting fitting 3 for connecting a first single-wall pipe A and a second double-wall pipe B. Similarly, [Fig.5] shows a sectional view of the connecting fitting 3 for connecting two double-wall pipes A, B.

[0053] The connecting connector 3 comprises a first connecting end 31, configured to be mechanically connected to the first connector 1, and a second connecting end 32 configured to be mechanically connected to the second connector 2. The connecting connector 3 extends longitudinally along the axis X for the connection of two pipes A, B. For the connection of three pipes A, B, C (as shown in Figures 6 and 7), the connecting connector 3 comprises also a third connection end 37 configured to cooperate with a third connector 4 mounted on a connection end C1 of a third pipe C. In this embodiment, the connection fitting 3 preferably has a T shape, as will be described in more detail later.

[0054] According to one aspect of the invention, with reference to [Fig. 4], the connecting connector 3 comprises an outer connecting conduit 34 and an inner connecting conduit 33 mounted in the outer connecting conduit 34. Preferably, the inner connecting conduit 33 and the outer connecting conduit 34 are concentric. Hereinafter, for the sake of brevity, the inner connecting conduit 33 will be designated “inner conduit 33” and the outer connecting conduit 34 will be designated “outer conduit 34”.

[0055] In this example, the inner conduit 33 is configured to fluidly connect the tube TA of the first pipe A and the inner tube TI-B of the second pipe B. The outer conduit 34 is configured to be connected to the outer tube TE-B of the second pipe B. At the first connection end 31, the outer conduit 34 is in this example blind, since the first pipe A is a single-walled pipe. In the case of the connection of two double-walled pipes (as shown in [Fig. 5]), the outer conduit 34 is configured to be connected to the outer tube TE-A of the first pipe A and to the outer tube TE-B of the second pipe B to fluidly connect them. The inner conduit 33 and the outer conduit 34 form a double-walled connection fitting 3 which makes it possible to guarantee safety even in the event of a leak in the inner conduit 33.

[0056] In practice, the outer conduit 34 is connected to the outer tube TE-B of the second pipe B via the second connector 2 and the inner conduit 33 is connected to the tube TA of the first pipe A via the first connector 1. The inner conduit 33 is, moreover in this example, connected directly to the inner tube TLB of the second pipe B. In this example, the inner conduit 33 is mounted by fitting around the inner tube TLB of the second pipe B. As such, the inner conduit 33 preferably has an inner diameter D33 substantially equal (i.e. to within a mounting clearance) to the outer diameter DB of the inner tube TLB of the second pipe B (as shown in [Fig. 4]). Preferably, a seal J (shown in [Fig. 4]) is sandwiched between the inner tube TLB of the second pipe B and the inner conduit 33 of the connecting connector 3, so as to form a sealed connection.

[0057] In this example, the inner conduit 33 and the outer conduit 34 have a tubular shape. Preferably, the connecting conduits 33, 34 have the shape of a right circular cylinder, so as to cooperate by complementarity of shape with one of the connectors 1, 2 and / or the inner tube TLB of the second pipe B. It goes without saying that the connecting conduits 33, 34 could alternatively have a different shape, for example the shape of a cylinder with a square or rectangular base.

[0058] The inner duct 33 is preferably a single piece. In this example, the inner duct 33 is manufactured by molding, that is to say by injecting thermoplastic into a press. It goes without saying that the manufacturing method could be different.

[0059] According to a characteristic of the invention, the outer conduit 34 is a single piece. In this example, the outer conduit 34 is manufactured by overmolding thermoplastic material onto the inner conduit 33.

[0060] According to one aspect of the invention, the inner conduit 33 is trapped in the outer conduit 34, so as to prevent any separation of the inner conduit 33 and the outer conduit 34. By the term "trapped", it is meant that the inner conduit 33 is trapped in the outer conduit 34, that it is mounted in a captive manner in the outer conduit 34. In other words, the inner conduit 33 and the outer conduit 34 are inseparable.

[0061] Still with reference to [Fig. 4], the inner conduit 33 and the outer conduit 34 are mounted precisely relative to each other. More precisely, the inner connecting conduit 33 is mounted at a determined position in the outer connecting conduit 34 so as to ensure the connection of the inner conduit 33 with the inner tube TLB of the second pipe B when the outer conduit 34 is connected with the outer tube TE-B of the second pipe B via the second connector 2. In other words, thanks to the precise positioning between the inner conduit 33 and the outer conduit 34, the inner conduit 33 is configured to automatically fit around the inner tube TLB of the second pipe B when the outer conduit 34 and the outer tube TE-B are connected.

[0062] In the case of the connection of two double-walled pipes, the precise positioning of the inner conduit 33 in the outer conduit 34 makes it possible to guarantee the connection of the inner conduit 33 with the inner tube TLA of the first pipe A and with the inner tube TLB of the second pipe B during the connection of the outer conduit 34 respectively with the outer tube TE-A of the first pipe A and with the outer tube TE-B of the second pipe B.

[0063] For this, as shown in [Fig. 4], the connecting connector 3 comprises, in one embodiment, a spacer 8 mounted between the inner conduit 33 and the outer conduit 34, so as to connect them mechanically. The spacer 8 makes it possible, in the case of a connection of two double-walled pipes, to form a single-piece connecting connector 3. In this example, the spacer 8 has a height h, defined between the inner conduit 33 and the outer conduit 34 of between 12.7 and 25.4 x 103 m, so as to center the inner conduit 33 in the outer conduit 34 to allow a homogeneous flow in the outer conduit 34. Preferably, the connecting connector 3 comprises a plurality of spacers 8 distributed circumferentially tightly around the inner duct 33, to ensure optimal support.

[0064] For the connection of a single-walled pipe with a double-walled pipe, the outer pipe 34 being preferably blind, the latter is connected to the inner pipe 33, forming a single-piece assembly, as shown in [Fig. 4]. In this embodiment, one or more spacers 8 can also be added.

[0065] As described above, the first connection end 31 is configured to be mechanically connected to the first connector 1 and the second connection end 32 is configured to be mechanically connected to the second connector 2. For this, each connection end 31, 32 has a cylindrical shape to cooperate by shape complementarity with the connecting portion 12, 22 of the connector 1, 2 mounted opposite. It goes without saying that the shape of the connection end 31, 32 could be different to cooperate with a connector 1, 2 which would have a different shape, the important thing being that the connecting portion 12, 22 of the connector 1, 2 and the connecting end 31, 32 opposite have complementary shapes.

[0066] In particular, each connection end 31, 32 defines an inner cylindrical surface intended to be in contact with an outer surface of the connecting portion 12, 22 of the connector 1, 2. Indeed, still with reference to [Fig. 4], each connection end 31, 32 is configured to be mounted on the connecting portion 12, 22 of the connector 1, 2 opposite by interlocking. In other words, the first connection end 31 preferably has an inner diameter D31 substantially equal to the outer diameter D12 of the connecting portion 12, 22 of the connector 1, 2 to allow them to cooperate while limiting the risk of leakage. By "substantially equal" is meant here that the internal diameter D31 of the first connecting end 31 is slightly greater than the external diameter D12 of the connecting portion 12, 22 of the connector 1, 2 to allow the two parts to fit together, without there being too much play between the two.A connection by interlocking is described, however, it goes without saying that each connection end 31, 32 could cooperate with the connection portion 12, 22 of the connector 1, 2 opposite in a different manner.

[0067] In this example, the free end of each connection end 31, 32 comprises a connection collar 35, 36 which extends in radial projection. The connection collar 35, 36 is configured to be pressed along the longitudinal axis X against the connection collar 13, 23 to mechanically connect each connection end 31, 32 to each respective connector 1, 2. For this, the connection collars 35, 36 have a diameter Dr (shown in [Fig. 3]) similar to the diameter De of the connection collars 13, 23.

[0068] To lock the connecting fitting 3 with each connector 1, 2, the locking member 5 mentioned above is configured in this example to jointly lock each connecting collar 35, 36 with the connecting collar 13, 23 mounted opposite each other to prevent any axial movement. In this example, the locking is achieved by clipping. The securing member 6 is configured, in this example, to prevent the collars from becoming detached. Preferably, the securing member 6 is configured to radially cover the locking member 5 to prevent accidental unclipping. It goes without saying that the locking of the connecting fitting 3 on each connector 1, 2 and the securing of the connection could be achieved in a different manner.

[0069] In one embodiment, as described above, the fluid circuit CF comprises a first pipe A, a second pipe B, a third pipe C and a connecting fitting 3 intended to be mounted at the interface between the three pipes A, B, C to fluidically connect them. The three pipes A, B, C and the connecting fitting 3 are made of a thermoplastic material.

[0070] In this example shown in [Fig.6], the third pipe C extends longitudinally along the vertical axis Z, so as to be positioned perpendicular to the first pipe A and the second pipe B which are themselves mounted opposite each other.

[0071] In this example, each pipe A, B, C comprises an outer tube TE-A, TE-B, TE-C and an inner tube TLA, TLB, TLC, mounted respectively in each outer tube TE-A, TE-B, TE-C. It goes without saying that the connecting fitting 3 could just as easily connect three pipes, only one of which would be a double-walled pipe, the other two being single-walled pipes. The invention also applies to the connection of two double-walled pipes and one single-walled pipe. Similarly, it goes without saying that the connecting fitting 3 could also allow the connection of four pipes, at least one of which would be a double-walled pipe.

[0072] In a similar manner to the first pipe A and the second pipe B, the third pipe C has a connection end C1 which comprises a connector 4, designated “third connector” 4. The third connector 4 is similar to the second connector 2 described previously, configured to be mounted at one end of a double-walled pipe.

[0073] In this example, the connecting fitting 3, a close-up sectional view of which is shown in [Fig.7], has a “T” shape and comprises a first connecting end 31 configured to cooperate with the first connector 1 mounted on the connecting end A1 of the first pipe A, a second connecting end 32 configured to cooperate with the second connector 2 mounted on the connection end B1 of the second pipe B and a third connection end 37 configured to cooperate with the third connector 4 mounted on the connection end Cl of the third pipe C.

[0074] In a similar manner to the connection of two pipes A, B, the connecting fitting 3 is preferably a single piece. In other words, the inner conduit 33 which has a T shape is mounted in a trapped manner in the outer conduit 34 which also has a T shape.

[0075] The third connector 4 then comprises a locking member 5 and a securing member 6 for locking the third pipe C and the third connection end 37 of the connecting connector 3.

[0076] A method for connecting a first pipe A and a second pipe B will now be described, with reference to [Fig. 8], according to an embodiment of the invention. In this example, the first pipe A and the second pipe B are double-walled pipes. The first connector 1 is fixedly mounted on the connection end A1 of the first pipe A and the second connector 2 is fixedly mounted on the connection end B1 of the second pipe B.

[0077] The method will be described firstly for the connection of the connecting fitting 3 to the first pipe A.

[0078] In a first step E1, an operator positions the first connection end 31 of the connecting connector 3 opposite the connection end A1 of the first pipe A. More precisely, in this step E1, the inner connecting conduit 33 is substantially aligned with the inner tube TLA of the first pipe A and the outer connecting conduit 34 is substantially aligned with the first connector 1 mounted on the outer tube TE-A of the first pipe A.

[0079] The operator then moves, in a second step E2, the connecting connector 3 along the longitudinal axis X towards the connection end A1 of the first pipe A. In this example, the external conduit 34 is guided by the connector 1 to align it substantially with the external tube TE-A of the first pipe A.

[0080] In a third step E3, the outer conduit 34 is manually fitted onto the first connector 1 so as to connect the outer conduit 34 with the outer tube TE-A of the first pipe A. In this step, the inner conduit 33 is blindly connected with the inner tube TLA of the first pipe A. In other words, the connecting connector 3 makes it possible to simultaneously connect each conduit 33, 34 respectively with the two inner tubes TLA and outer TE-A of the first pipe A. A seal J preferably positioned between the inner conduit 33 and the inner tube TLA makes it possible to guarantee the tightness of the connection.

[0081] In a preferred embodiment, the connecting collar 35 of the connector connecting member 3 is pressed against the connection collar 13 of the connector 1. These are blocked by clipping by the locking member 5 which thus prevents any disconnection of the connecting connector 3 and the first pipe A. The operator then moves the securing member 6 onto the locking member 5 to prevent it from being unlocked involuntarily. In this example, the securing member 6 is also connected to the locking member 5 by clipping. It goes without saying that the locking and securing could be carried out in a different way.

[0082] All of the steps are then repeated for the connection of the connecting connector 3 to the second pipe B. In the first step E1 of positioning the second connecting end 32 opposite the second pipe B, the inner conduit 33 of the connecting connector 3 is positioned opposite the inner tube TLB of the second pipe B and the outer conduit 34 of the connecting connector 3 is positioned opposite the second connector 2 mounted on the outer tube TE-B of the second pipe B.

[0083] When the operator moves the connecting connector 3 along the longitudinal axis X, the inner connecting conduit 33 is fitted blindly onto the inner tube TL B of the second pipe B when connecting the outer connecting conduit 34 with the outer tube TE-B of the second pipe B via the second connector 2. A seal J preferably positioned between the inner connecting conduit 33 and the inner tube TLB makes it possible to guarantee the tightness of the connection.

[0084] When the connecting connector 3 is a T-shaped connector comprising three connecting ends 31, 32, 37, for connecting three pipes A, B, C, all of the steps are repeated to connect the third pipe C. Alternatively, a T-shaped connecting connector 3 can only allow the connection of two pipes A, B. In this case, a closure member (not shown) is in this example put in place to plug the third connecting end 37 and avoid any risk of leakage.

Claims

Claims

1. Fluid circuit (CF), in particular for aircraft, comprising: • at least one first pipe (A) made of thermoplastic material comprising a connection end (Al) comprising a connector (1), hereinafter “first connector”, the first pipe (A) comprising at least one tube (TA), • at least one second pipe (B) made of thermoplastic material comprising a connection end (B1) comprising a connector (2), hereinafter “second connector”, the second pipe (B) comprising an outer tube (TE-B) and an inner tube (TI-B) mounted in the outer tube (TE-B), the first pipe (A) and the second pipe (B) extending along a longitudinal axis (X), and • a connecting connector (3) made of thermoplastic material, for sealingly connecting the two connection ends (Al, Bl), comprising: • at least one first connection end (31) configured to be mechanically connected to the first connector (1), • at least one second connection end (32) configured to be mechanically connected to the second connector (2), • an internal connecting conduit (33) configured to fluidically connect at least the tube (TA) of the first pipe (A) and the internal tube (TI-B) of the second pipe (B), an external connecting conduit (34) configured to cooperate with at least the external tube (TE-B) of the second pipe (B), the external connecting conduit (34) being in one piece, the inner connecting conduit (33) being trapped in the outer connecting conduit (34) so ​​as to prevent any separation of the inner connecting conduit (33) and the conduit external connecting conduit (34), the internal connecting conduit (33) being mounted at a determined position in the external connecting conduit (34) so ​​as to allow a connection of the internal connecting conduit (33) with at least the internal tube (TI-B) of the second pipe (B) in a blind manner when connecting the external connecting conduit (34) with at least the external tube (TE-B) of the second pipe (B).

2. Fluid circuit (CF) according to claim 1, comprising at least one spacer (8) mounted between the inner connecting conduit (33) and the outer connecting conduit (34), so as to connect them mechanically, the connecting connector (3) forming a single-piece assembly.

3. Fluid circuit (CF) according to one of claims 1 to 2, in which the connecting connector (3) is made of a thermoplastic material chosen from: polyetheretherketone and polyamides loaded with glass fibers.

4. Fluid circuit (CF) according to one of claims 1 to 3, wherein the tube (TA) of the first pipe (A) is an inner tube (TI-A), the first pipe (A) comprising an outer tube (TE-A), the inner tube (TI-A) being mounted in the outer tube (TE-A), the inner connecting conduit (33) of the connecting connector (3) is configured to fluidically connect the inner tube (TI-A) of the first pipe (A) and the inner tube (TI-B) of the second pipe (B), and the outer connecting conduit (34) is configured to connect the outer tube (TE-A) of the first pipe (A) and the outer tube (TE-B) of the second pipe (B).

5. Fluid circuit (CF) according to one of claims 1 to 4, comprising a third pipe (C) made of thermoplastic material extending along a lateral axis (Y) orthogonal to the longitudinal axis (X), the third pipe (C) comprising at least one tube (TC), the third pipe (C) comprising a connection end (Cl) comprising a connector (7), hereinafter "third connector", the connecting fitting (3) comprises a third connection end (37) configured to be mechanically connected to the third connector (7), the internal connecting conduit (33) being configured to fluidically connect the tube (TA) of the first pipe (A), the tube

6.

7.

8. interior (TI-B) of the second pipe (B) and the tube (TC) of the third pipe (C). Fluid circuit according to claim 5, in which the inner connecting conduit (33) and the outer connecting conduit (34) have a "T" shape in which the inner connecting conduit (33) is trapped in the outer connecting conduit (34). Aircraft comprising at least one fluid circuit according to one of claims 1 to 6. Method for connecting at least a first pipe (A) and a connecting fitting (3) made of thermoplastic material of a fluid circuit (CF) according to one of claims 1 to 6, the method comprising at least the steps consisting of: connecting the outer connecting conduit (34) of the connecting fitting (3) with at least the outer tube (TE-B) of the second pipe (B), and simultaneously, blindly connecting the inner connecting conduit (33) with at least the inner tube (TI-B) of the second pipe (B).

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