FLUID CIRCUIT AND METHOD FOR CONNECTING PIPES OF SUCH A FLUID CIRCUIT

A fluid circuit, in particular for an aircraft, comprising at least one first duct (1) and a first connecting member (5), at least one second duct (2) and a second connecting member (6), a connector piece (3), for joining the two connection ends of the ducts (1, 2) in a leaktight manner, comprising a central sleeve (4) configured to cooperate, at a first end, with the first connecting member (5) and, at a second end, with the second connecting member (6), the central sleeve (4) having a plurality of flexible teeth (41) in order to correct any error in alignment between the first axis (X1) and the second axis (X2).

TECHNICAL FIELD

The present invention relates to the field of fluid circuits in an aircraft, for example, a drinking water, wastewater, drainage circuit, etc. The invention also relates to the connection of pipes of such a fluid circuit.

In a known manner, a fluid circuit comprises a plurality of pipes mechanically and fluidically linked to each other. When setting up a fluid circuit in an aircraft, the pipes are independently made integral with the structure of the aircraft and then fluidly connected to each other. In other words, the pipes are not movable relative to each other, but fixed when connected. Pipes are subject to thermal expansion. In practice, a small axial clearance can be contemplated to take account of relative deformations or movements between the pipes and the surrounding supporting structure. To connect a first pipe to a second pipe, it is known to use a linking connector that has to be mounted at the interface between the first pipe and the second pipe in order to ensure a sealed connection.

As an example, with reference toFIGS.1and2, a first pipe101and a second pipe102are represented which extend longitudinally along an axis X and which are sealingly linked by a connector103capable of translating axially on the first pipe101to cooperate with the end of the second pipe102. Each pipe101,102comprises a connection end111,121to which a connection element112,122is mounted.

In practice, with reference toFIG.3, when the pipes101,102are positioned, it is difficult to guarantee that their connection ends111,121are perfectly rectilinear due to manufacturing tolerances, pre-bending steps, mounting tolerances, etc. Misalignment is even more likely to occur when the pipes101,102are made of thermoplastic material. Due to this misalignment, it is difficult to position the linking connector103and ensure sealing.

An immediate solution would be to provide a high rigidity connector103which would stress the connection ends111,121of the pipes101,102in order to align them axially. A high rigidity connector103would require applying significant forces to the pipes101,102during mounting and would not allow absorbing the expansion effects axially. It is known from document U.S. Pat. No. 3,596,934 a tube coupling system according to prior art.

Thus, the invention aims to eliminate at least some of these drawbacks.

SUMMARY

The invention relates to a fluid circuit, in particular for aircraft, comprisingat least one first pipe comprising a first connection end, extending along a first axis and defining an internal surface and an external surface, the first connection end comprising a first peripheral connection element as well as a first linking member translationally and rotationally free about the first axis,at least one second pipe comprising a second connection end, extending along a second axis and defining an internal surface and an external surface, the second connection end comprising a second peripheral connection element as well as a second linking member translationally and rotationally free about the second axis, the connection ends of the pipes being fixed and spaced apart by an axial connection clearance,a linking connector, to sealingly link the two connection ends, comprising:a central sleeve comprising a peripheral casing adapted to slide along the second axis, the central sleeve being configured to cooperate, at a first end, with the first linking member and, at a second end, with the second linking member,the central sleeve comprising a plurality of flexible teeth configured to cooperate with the second peripheral connection element in order to correct a possible misalignment between the first axis and the second axis.

By means of the invention, the central sleeve can be conveniently manufactured and then linked to the linking members later. Advantageously, the flexible teeth allow the central sleeve to be guided while allowing its tilt during connection, which makes it possible to conveniently compensate for any misalignment.

Preferably, the flexible teeth of the central sleeve are circumferentially distributed. Thus, cooperation is optimum for any type of misalignment.

Preferably, the second linking member comprises a plurality of flexible teeth configured to cooperate with the second connection end in order to correct a possible misalignment between the first axis and the second axis when the second linking member cooperates with the central sleeve. The teeth of the second linking member also make it possible to compensate for misalignment. Thus, forces related to misalignment are optimally distributed to limit the risk of failure and breakage.

Preferably, the first linking member comprises a plurality of flexible teeth configured to cooperate with the first connection end in order to correct a possible misalignment between the first axis and the second axis when the first linking member cooperates with the central sleeve. Preferably, the flexible teeth are circumferentially distributed.

Preferably, the first linking member comprises a corrugated linking portion linking the flexible teeth. Such a linking portion provides flexibility to the teeth and allows for clearance.

According to a preferred aspect, the first linking member comprises openings, preferably cylindrical, formed in the corrugated linking portion, to spread the flexible teeth apart. In addition to improved flexibility, such openings reduce mechanical stresses in the first linking member.

Preferably, the linking portion has an external elbow having a first radius of curvature and an internal elbow having a second radius of curvature less than the first radius of curvature so as to ensure flexibility and damping making it possible to compensate for misalignments without generating stresses.

According to one aspect, each flexible tooth is tilted towards the first axis by an angle of between 2° and 5° in order to ensure progressive contact with the first pipe while limiting the mounting forces.

Preferably, the flexible teeth of the second linking member are circumferentially distributed.

According to one aspect of the invention, the first linking member and the second linking member are identical. This facilitates industrialization. In addition, the forces applied to the connector are analogous at both ends.

Preferably, at least one end of the central sleeve comprises a clamping device configured to cooperate with a linking member. A clamping device allows axial clamping to guarantee the durability of the connection.

According to a preferred aspect, the clamping device comprises at least one guide slot, preferably, so as to allow quarter-turn clamping. Advantageously, an axial clamping is conveniently carried out by guided rotation of a linking member. A bayonet-type clamping is quick and convenient.

According to one aspect of the invention, the linking connector comprises a first sealing member and a second sealing member configured to cooperate respectively with the first connection end and the second connection end in the connection position. Thus, sealing is guaranteed.

Preferably, the sealing members have different diameters. When the sleeve is made by thermoplastic injection, a relief angle is provided so as to allow demolding the same. The sealing members have different diameters in order to ensure optimum sealing taking account of this relief angle.

The invention also relates to an aircraft comprising a fluid circuit as set forth previously, wherein the first pipe and the second pipe are made integral with a structure of the aircraft, the connection ends of the pipes being fixed and spaced apart by an axial connection clearance.

The invention also relates to a method for connecting at least a first pipe and a second pipe by means of a linking connector of a fluid circuit as set forth previously, the connection ends of the pipes being fixed and spaced apart by an axial connection clearance, the linking connector extending over a connection end of a pipe, the method comprising a step of moving the central sleeve of the linking connector between the connection ends, the flexible teeth of the central sleeve cooperating with the second peripheral connection element in order to correct a possible misalignment between the first axis and the second axis.

Preferably, the method comprises a step of cooperating the second linking member with the central sleeve so as to lock the linking connector.

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 where applicable.

DETAILED DESCRIPTION

A fluid circuit according to the invention intended for aeronautical use, in particular, for the transport of fuel, water and oxygen, air, fire-retardant gas, refrigeration, etc., will now be set forth.

In this example, the fluid circuit comprises a plurality of pipes that are coordinated with each other in order to guide a fluid. For an aeronautical application, the individual pipes are firstly made integral with a structure of the aircraft, and then secondly connected to each other.

Subsequently, the invention will be set forth for the connection of two pipes of a fluid circuit. Nonetheless, the invention also applies to the connection of more than two pipes, in particular three pipes.

With reference toFIG.4, one embodiment of a fluid circuit according to the invention is represented which comprises a first pipe1, a second pipe2and a linking connector3mounted at the interface between the first pipe1and the second pipe2, in order to fluidically connect the first pipe1to the second pipe2.

In this embodiment, each pipe comprises a tubular body which is terminated at each end by a connection end. The tubular body of each pipe preferably comprises bent portions so as to allow the fluid circuit to conveniently link different pieces of equipment by overcoming positioning restrictions. In addition, each pipe defines an internal surface, in contact with the fluid to be conveyed, and an external surface, opposite to the internal surface.

With reference toFIG.5, the first pipe1comprises a first connection end11, extending along a first axis X1and defining an internal surface and an external surface. The first connection end11comprises a first connection element12, in particular, an L-shaped peripheral connection ring.

Analogously, still with reference toFIG.5, the second pipe2comprises a second connection end21, extending along a second axis X2and defining an internal surface and an external surface. The second connection end21comprises a second peripheral connection element22, in particular, a connection ring. The axes X1, X2are preferably aligned but can be offset by an angular offset of up to 10° or a vertical/lateral offset of up to 10 mm.

Preferably, the connection rings12,22are split rings, still preferably, each connection ring12,22has an L-shaped cross section. Pipes1,2have analogous structures to enable industrialization at lower costs. It goes without saying that the connection elements12,22could be in other forms, in particular a castellated crown or a lug. Preferably, each connection element12,22has an axial thickness in the order of 2 mm and a radial length of between 4 mm and 8 mm relative to the axis X1, X2.

In this embodiment, as illustrated inFIG.5, the distance between the first connection element12and the end edge of the first pipe1is greater than the distance between the second connection element22and the end edge of the second pipe2. This advantageously makes it possible to pre-mount the linking connector2between the first peripheral connection element12and the end edge of the first pipe1as will be set forth later. Thus, it is sufficient to translate the linking connector3housed on the first pipe1to ensure sealing with the second pipe2.

It goes without saying that each connection end11,21could also be formed by a connection end cap which would be mounted in an add-on manner with its connection element21,22.

As illustrated inFIG.5, the connection ends11,21of the pipes1,2are fixed and spaced apart by an axial connection clearance Jx, of between 5 mm and 10 mm, which is filled by the movement of the linking connector3as will be set forth later.

Each pipe1,2has a tubular body which comprises one or more bent portions. The diameter of the tubular body and/or of each connection end is preferably between 12.7 mm and 50.8 mm. Preferably, each pipe1,2is made of plastic material, but it goes without saying that other materials may be suitable, for example, a metal material. For a metal design, the linking connector3preferably comprises a metallization in order to ensure electrical conductivity. Preferably, the central sleeve4, the flexible teeth41and the linking members5,6comprise a metallization, for example, at least one metallization strip.

InFIG.5, the axes X1, X2are oriented from right to left. As will be set forth in the example implementation, the linking connector3allows the two pipes1,2which are spread apart to be placed in fluid communication.

The first pipe1further comprises a first linking member5, translationally and rotationally free about the first axis X1, configured to cooperate with a first end of the linking connector3. Analogously, the second pipe2further comprises a second linking member6, translationally and rotationally free about the second axis X2, configured to cooperate with a second end of the linking connector3. In other words, the linking members5,6allow immobilizing and securing the position of the linking connector3. The linking members5,6are not positioned between the connection elements12,22but externally to the latter. Preferably, the linking members5,6are mounted captively to the connection ends11,21so as to avoid their loss when handling a pipe1,2. Thus, the first linking member5is mounted to the left of the first connection element12while the second linking member6is mounted to the right of the second connection element22. The structure and function of the linking members5,6will be set forth later.

As will be set forth later, the first linking member5and the central sleeve4are pre-mounted to the first pipe1while the second linking member7is pre-mounted to the second pipe2. The first linking member5is linked to the central sleeve4during premounting, in particular in the workshop, while the second linking member6is linked to the central sleeve4in situ, in particular in an aircraft.

Still with reference toFIG.5, the fluid circuit comprises a linking connector3configured to mechanically link the two connection ends11,21. The linking connector3comprises a central sleeve4, a first sealing member71, a second sealing member72, a first spreader8and a second spreader9.

In this exemplary embodiment, the central sleeve4is configured to extend externally to the connection ends11,21in order to ensure a fluidic connection between the pipes1,2. The central sleeve4is configured to compress the sealing members71,72in order to ensure sealing between the connection ends11,21. The central sleeve4has an internal diameter slightly smaller than that of the sealing members71,72, so as to compress the same radially.

As illustrated inFIGS.5and6, the central sleeve4is in the form of a peripheral casing that axially extends along the first axis X1. In the mounted position, the central sleeve4is adapted to slide along the first axis X1on the connection end11of the first pipe1. With reference toFIG.6, the central sleeve4comprises a first portion4A intended to extend to the side of the first pipe1in the locked position and a second portion4B intended to extend to the side of the second pipe2in the locked position.

The central sleeve4comprises, at the second portion4B, a plurality of flexible teeth41configured to cooperate with the second connection element22in order to correct a possible misalignment between the first axis X1and the second axis X2. The flexible teeth41extend in parallel to the first axis X1and have the same axial position so as to form a castellated crown. In this example, with reference toFIG.7, each flexible tooth41has a length of between 2 mm and 20 mm, in order to allow angular clearance of less than or equal to 10°. The flexible teeth41are spread apart from each other, in particular in a distributed manner.

With reference toFIG.5, the flexible teeth41are aligned radially with the second sealing member72so as to allow the flexible radial teeth41to move the second sealing member72during a longitudinal movement of the central sleeve4towards the first pipe1.

The central sleeve4comprises, at the second portion4B, a radial crown42extending externally to the flexible teeth41and advantageously enabling the central connector4to be handled without damaging the flexible teeth41.

With reference toFIGS.5and6, the first portion4A of the central sleeve4is linked to the second portion4B by a substantially cylindrical sheath43in which the sealing members71,72and the spreaders8,9are housed.

The central sleeve4comprises, at each portion4A,4B, a clamping device46configured to cooperate with a linking member5,6. In this example, with reference toFIG.6, each clamping device46comprises a plurality of guide slots47, formed at the periphery of the clamping device46, to allow axial blocking following angular rotation of a linking member5,6, especially quarter-turn clamping. It goes without saying that other clamping means may be suitable, in particular, a screw pitch.

The central sleeve4further comprises a first locking member48configured to cooperate with the first linking member5and a second locking member49configured to cooperate with the second linking member6. Such locking devices48,49make it possible to prevent any unintentional removal of the linking members5,6.

As illustrated inFIGS.5and6, the locking members48,49extend longitudinally along the first axis X1radially externally to the sleeve43. The locking members48,49are linked by a radial wall44to the sheath43allowing each locking member48,49to be able to tilt towards the center of the central sleeve4relative to the first axis X1in order to cooperate with a linking member5,6. The locking members48,49respectively comprise, at their free ends, locking teeth481,491radially protruding outwards so as to be able to be introduced into a through-hole of a linking member5,6.

Preferably, the central sleeve4is unitary, that is, formed as one-piece, which makes it possible to dispense with a mechanical hinge that could wear out or represent a fragile zone. Preferably, the central sleeve4is made of a thermoplastic material.

In this embodiment, with reference toFIG.5, the linking connector3comprises a first sealing member71and a second sealing member72to ensure sealing with the central sleeve4respectively with the first connection end11and the second connection end21. Each sealing member71,72has a toric shape and is made of an elastic material.

In this example, the first sealing member71has a larger diameter than the second sealing member72so as to allow tilting of the linking connector3with respect to the first axis X1.

Still with reference toFIG.5, the linking connector3comprises a first spreader8, positioned between the first linking member11and the first sealing member71and a second spreader9positioned longitudinally between the two sealing members71,72.

The first spreader8and the second spreader9advantageously make it possible to hold the sealing members71,72and move them together when moving the central sleeve4. To this end, the longitudinal ends of the second spreader9are curved so as to fit closely the shape of sealing members71,72of circular cross section.

When moving the central sleeve4to the right (towards the second pipe2), the first linking member5moves the first spreader8which moves the first sealing member71which moves the second sealing member72by means of the second spreader9. Thus, the sealing members71,72are moved concomitantly, which ensures optimum sealing when setting up or removing the linking connector3.

In order to hold the linking connector3in the connection position between the connection ends11,21, the linking members5,6lock the central sleeve4. In this embodiment, the linking members5,6are identical and only the first linking member5will be set forth later for clarity and conciseness.

With reference toFIGS.8and9, the first linking member5comprises a plurality of flexible teeth51configured to cooperate with the external surface of the first pipe1in order to correct a possible misalignment between the first axis X1and the second axis X2. The flexible teeth51extend in parallel to the first axis X1and have the same axial position. In this example, the flexible teeth51are substantially analogous to the flexible teeth41previously set forth and are arranged to form a crown.

With reference toFIG.8, the flexible teeth51are spread apart by cylindrically shaped openings54in order to avoid stress concentration.

The flexible teeth51are linked to an external annular crown52via a linking portion53. In this example, the linking portion53has a corrugated cross section, preferably S-shaped, so as to increase flexibility and allow relative tilt between the flexible teeth51(which align with the first axis X1) and the external annular crown52which aligns with the central sleeve4along the second axis X2.

Preferably, the openings54are formed in the linking portion53configured, on the one hand, to make an elastic link in order to withstand strains and, on the other hand, to ensure sufficient rigidity to allow realignment of the axes X1, X2. With reference toFIG.9, to this end, the linking portion53has a thickness in the order of 1 to 2 mm, an external elbow53ehaving a radius of curvature of between 2 mm and 3 mm and an internal elbow53ihaving a radius of curvature of between 1 mm and 2 mm. Preferably, each flexible tooth51is tilted towards the axis by an angle of between 2° and 5° so as to come into contact with the external surface of the first pipe1and correct its orientation by putting a strain on the linking portion53.

The external annular crown52has a through-hole521for receiving the locking tooth481of the first locking member48of the central sleeve4. The external annular crown52further comprises a plurality of internal radial fingers522, angularly distributed, configured to be guided into the guide slots47of the guide device46formed on the central sleeve4in order to allow axial clamping.

Analogously, the second linking member6comprises a plurality of flexible teeth61configured to cooperate with the external surface of the second pipe2. The flexible teeth61extend in parallel to the second axis X2.

The linking connector3according to the invention comprises a very limited number of elements in this embodiment, which reduces its cost. Furthermore, advantageously, each element can be made at low cost, in particular by plastic injection, which especially reduces its mass.

According to a preferred aspect of the invention, the linking connector3is pre-mounted at the connection end11of the first pipe1by means of the first linking member5as illustrated inFIG.10. The second linking member6is not connected. In this pre-mounting position, the sealing members71,72are in contact with the first connection end11and the first linking member5is positioned very far to the left of the first connection element12.

Such pre-mounting is very advantageous as it avoids the need for an operator to use add-on parts to connect the two pipes1,2. The first pipe1can thus be easily handled with its linking connector3. Indeed, the linking connector3can be closed and secured directly. Pre-mounting advantageously allows the linking connector3to be positioned when the pipes1,2are attached to an aircraft structure, which provides significant time savings. However, it goes without saying that linking connector3could be retrofitted.

A method for connecting a first pipe1and a second pipe2by means of a linking connector3according to one embodiment of the invention will now be set forth. In this example, the pipes1,2have been previously made integral with a structure of an aircraft and are not movable with respect to each other.

With reference toFIG.10, the connection ends11,21of the pipes1,2are fixed and spaced apart by an axial connection clearance Jx, the linking connector3is pre-mounted to the connection end11of the first pipe1as explained previously.

In order to make a connection, with reference toFIG.11, the method comprises a step of axially moving E1the linking connector3along the first axis X1until it extends to the interface between the two connection ends11,21of the pipes1,2. Advantageously, this movement can be carried out by an operator using only one of their hands, which is convenient. Such a motion is simple to carry out since the operator only needs to move the central sleeve4to the right so as to move the first sealing member71and the second sealing member72to ensure sealing with the first connection end11and the second connection end21by means of the spreaders8,9.

Following the translational movement along the first axis X1, the flexible teeth41of the central sleeve4cooperate with the second connection element22of the second pipe2which extends along the second axis X2. Advantageously, any misalignment is compensated for by the flexible teeth41.

Finally, with reference toFIG.11, the second linking member6is moved to the left (step E2) so as to cooperate with the central sleeve4by quarter-turn screwing (step E3) in order to make a pull of the central sleeve4to the right in order to immobilize the linking connector3stably between the connection elements12,22(FIG.5). The locking tooth491of the second locking member4of the central sleeve4cooperates with the through opening621of the second linking member6. Advantageously, the flexible teeth61of the second linking member6also make it possible to compensate for misalignment between the central sleeve4and the second pipe2.

Advantageously, even if the pipes1,2are not perfectly rectilinear, they can still be connected sealingly and durably. By means of the invention, two pipes1,2can be connected physically and fluidly by an operator without risk of error and conveniently.