FR3002612A1 - Sealed connection system for double skin pipes of aircraft's fuel circuit, has external connection device for connecting external tube and equipped with tightening unit to connect external rings, where one of rings is attached to tube - Google Patents

Abstract

The system has an internal connection device for connecting an internal tube (11) equipped with a male connection (31) and a female connection (32). The male connection is inserted into the female connection according to longitudinal direction (X). The connection device includes an internal seal to assure sealing between the connections. One of the connections is attached to the tube. An external connection device (40) for connecting an external tube (12) is equipped with external rings (41, 42) and a tightening unit (50) to connect the rings. One of the rings is attached to the external tube.

Description

The present invention relates to a sealed connection system for a double-skinned pipe, and a hydraulic circuit provided with this system. More particularly, the invention lies in the technical field of means for connecting double-skinned pipes of a fuel circuit, such as a fuel system of an aircraft for example. Indeed, a fuel leak in a fuel system 10 may lead to ignition risks. To minimize these risks, it is known to use double-skinned pipes, sometimes called "double-skinned" or "double-walled". Such a double skin hose thus has an inner tube 15 housed in an outer tube, each tube thus representing a "skin" or an "envelope" or a "wall" according to the vocabulary used. The fuel then circulates within the inner tube under normal conditions. If this fuel leaks from the inner tube, the fuel remains nevertheless confined in the pipe, between the inner tube and the outer tube. In addition, a fuel system of an aircraft may comprise a plurality of rigid hoses or flexible hoses connected to each other. The installation of rigid pipes requires an isostatic mounting to overcome the deformations of the entire fuel circuit due for example to the forces undergone and temperature variations. Isostatic mounting is also required to take into account the angular tolerances to be respected and the relative position of the pipes to be connected.

Conversely, flexible hoses can easily be manipulated and overcome these constraints. In this context, the use of flexible hoses with double skin seems interesting, especially in the context of a fuel system of an aircraft. These double-skinned hoses, however, cause difficulty. Unlike a pipe with a single tube, connecting two double-skinned pipes can be complex to ensure the required seal.

There is known a device provided with a connector secured to one end of the inner tube of a flexible hose with double skin. This connection is provided with a fastener that can be screwed. In addition, the device is provided with a flexible sock tightened around the outer tube of the pipe.

Therefore, to fix the pipe to a tank for example, it screws the fastener to the tank, then the sock is fixed around the fitting on a tip through a clamp if necessary. The flexibility of the sock gives the device a certain freedom of movement. In addition, the sock can be rolled up to access the inner tube during maintenance steps. Despite its simplicity and interest, this device poses some difficulties. During assembly and maintenance phases, access to the various connection devices is sometimes difficult. Handling socks and putting them in place can be tricky and time consuming in a tight environment.

In addition, the mounting operation may involve a double seal check. The operator fixes the inner tube of a pipe through a fitting and checks its tightness, then installs the sock and checks its tightness.

In addition, each sock has a limited life. FR 2 849 151 discloses a "double skin" circuit comprising two rigid or semi-rigid outer tubes connected by an external connection and two flexible inner tubes connected by an internal connection.

Each connection has ferrules interconnected by a sheath. A nut is then screwed onto the sleeve to close the connection. Document FR 2 639 702 discloses a system for connecting two rigid double-skinned pipes. This connection system includes an internal connection device of the two inner tubes of the two pipes, and an external connection device of the two outer tubes of the two pipes. The internal connecting device comprises two rings attached to the ends of the inner tubes. The two rings are surrounded by a ring cooperating with two nuts. Therefore, the external connection device is provided with a sleeve, a first end is sealingly attached to an outer tube, by means of a nut on a half-connection welded to the outer tube. The second end of the sleeve can slide tightly on the other outer tube. Document US Pat. No. 8,172,272 discloses a system implementing a double-walled socket cooperating with a coupling partially housed between the two walls of said socket.

The present invention therefore aims to provide a sealed connection system of a double-skinned alternative hose to particularly facilitate its use, and limit the use of premature wear materials.

The invention therefore relates to a sealed connection system of a double skin hose provided with an inner tube housed in an outer tube. This system is provided with: - an internal connection device for connecting the inner tube provided on the one hand with a female connector and a male connector extending in a longitudinal direction, said male connector being insertable into said female connector in the longitudinal direction, and secondly at least one internal seal sealing between said female connector and said male connector, one of said connectors being securable to said inner tube, - a device external connecting device for connecting the outer tube provided with a first outer ring and a second outer ring, said external connecting device having a clamping means for connecting the first outer ring to the second outer ring, one of said outer rings can be secured to said outer tube. It will be understood that "internal" means cooperating with an inner tube and "external" cooperating with an outer tube. Therefore, and to connect the pipe to a reservoir, the inner pipe of the double skin pipe is secured to a connection of the internal connection device. One can then fix the other connection to a single pipe immersed in the tank Similarly, an outer ring is secured to the outer tube of the double skin hose. The other outer ring can be attached to a connection board to open into a drained compartment To connect the tube to another double skin tube, the inner tube of a double skin tube is secured to a connection of the internal connection device , the outer tube of this double skin hose being attached to an outer ring. The other connector and the other outer ring are then secured to the inner tube and to the outer tube of the other double skin hose, respectively. This connection system can therefore both connect a double skin hose to another double skin hose, such as a tank for example. In addition, the connection system can be applied to both flexible double skin hoses and rigid double skin hoses. Regardless of which element to connect to a double skin hose, the connection system is easy to use. Indeed, an operator first connects the inner tube of the pipe by plugging the male connector into the female connector. The internal seal then seals the internal connection device, and therefore that of the first skin of the circuit. Therefore, the operator connects the outer tube by securing the outer rings to one another with the clamping means.

The external connection device then ensures the sealing of the second skin of the circuit and the fixing as such of the pipe. It will be seen later that an external sealing device can be implemented to maximize the sealing of the external connection device.

This system is therefore simple to implement, involving a single clamping operation. In addition, the system does not require the use of socks degrading over time. The connection system further has a bulk and a mass tending to be minimized. This connection system may further include one or more additional features that follow. Thus, the connection system may comprise at least one spacer ring intended to be interposed between the outer tube and the inner tube, this spacer ring having a plurality of longitudinal grooves allowing the passage of a fluid through the tube. the spacer ring. Each spacer ring keeps the inner tube of an outer tube of a double-skinned hose at a distance. Nevertheless, the presence of at least one groove makes it possible to guarantee the circulation of a fluid between the inner tube and the outer tube despite the internal exiguity of the system. In case of leakage of the inner tube, the leaking fluid can flow between the inner tube and the outer tube to be driven to a location intended to accommodate it. Furthermore, the internal connection device may comprise at least one circular internal groove of revolution formed in at least one of said female and male connectors, an internal seal being partially housed in said internal groove. For example, two internal seals may be disposed in two internal grooves of a fitting. It is understood that each internal seal protrudes from the internal groove which receives it to ensure the required seal.

For example, the internal connection device comprises at least one circular internal groove of revolution formed in an outer surface of the male connector facing the female connector, a seal being housed in said internal groove.

Conventional clamping devices may furthermore be used. According to a first embodiment, the external connection device is of the type known as the "olive fitting" in the French language.

Thus, the clamping means comprises a nut disposed around one of said first and second outer rings and being longitudinally blocked by at least one protrusion of this outer ring, this nut being screwed to a thread of the other outer ring.

Thus, an outer ring may extend from a fixed end secured to an outer tube for example towards a free end. This free end then has a protrusion acting axial stop cooperating with the nut. It is also possible to provide an external sealing device provided with external seals, or a sealing tape wound on the thread of the outer ring screwed to the nut. According to a second embodiment, each outer ring comprises at least one circular projection of revolution directed towards a medium external to the pipe, the external connection device comprising a sleeve enclosing the circular projections, said clamping means comprising at least one collar of tightening tightening said sleeve.

An operator then arranges the sleeve around the outer rings, then tightens the clamp to secure the assembly. Optionally, the sleeve comprises two half-sleeves, the clamping collar clamping said half-sleeves against each other. The two half-sleeves can be hinged to each other. Therefore, at least one outer seal is disposed between each outer ring and the sleeve. For example, at least one outer seal is disposed between each half-sleeve and said outer ring 10 as appropriate. In addition or alternatively, at least one outer seal is disposed between the outer rings. The invention further relates to a hydraulic circuit provided with a first pipe having a first inner tube housed in a first outer tube. The circuit comprises a sealed connection system according to the invention for connecting the first pipe, this system being provided with: an internal connection device provided on the one hand with a male connector and a female connector which is extend in a longitudinal direction, the male connector being insertable into said female connector in the longitudinal direction, and on the other hand at least one internal seal sealing between said male connector and said female connector, one of said connectors being secured to the first inner tube; - an external connection device provided with a first outer ring and a second outer ring, one of said outer rings being able to be secured to said inner tube, said external connecting device having clamping means for connecting the first outer ring to the second outer ring. The invention applies in particular to a fuel system and in particular an aircraft fuel system. This circuit may in particular comprise two double-skinned pipes to be connected to one another by a connection system. Therefore, the circuit may have a first double-skinned hose having a first inner tube housed in a first outer tube. In addition, the circuit includes a second double-skinned hose having a second inner tube housed in a second outer tube. To equip the double skin pipes, the male connector is then secured to an inner tube and the female connector is secured to the other inner tube. In addition, the first outer ring is secured to the first outer tube and the second outer ring is secured to the second outer tube. To connect the double-skinned pipes to one another, an operator first connects the inner tubes together by plugging the male connector into the female connector. Therefore, the Operator connects the outer tubes together by joining the outer rings to one another with the clamping means. The invention and its advantages will appear in more detail in the following description with exemplary embodiments given by way of illustration with reference to the appended figures which represent: FIG. 1, a connection system according to a first embodiment embodiment connecting a double skin pipe to a reservoir, - figure 2, a section explaining a spacer ring, - figure 3, a section of a connection system according to a first embodiment connecting two double pipes. 4, a section of a connecting system according to a first embodiment connecting two double-skinned pipes and being provided with spacing rings, FIGS. and 6, sections of a connection system according to a second embodiment connecting two double-skinned pipes and being provided with spacer rings.

The elements present in several separate figures are assigned a single reference. Note that three directions X, Y and Z orthogonal to each other are shown in some figures. The first direction X is called longitudinal. The term "longitudinal" is relative to any direction parallel to the first direction X. The second direction Y is said to be transverse. Finally, the third direction Z is said in elevation. Figure 1 shows a compartment 2 housing a fuel tank 3, such as a compartment of an aircraft 1. This compartment 2 is provided with drainage holes 2 '.

The aircraft 1 is further provided with a fuel pipe 4 capable of conveying the fuel contained in the tank 3 to another organ. For this purpose, the aircraft comprises a double skin hose 10 extending the fuel piping.

The present invention therefore relates to a system 20 for connecting the double skin hose 10, for example to a tank according to FIG. 1 or to another double skin hose according to FIGS. 3 to 5. With reference to FIG. a double-skinned hose 10 includes an inner tube 11 running through an outer tube 12. The inner tube represents a first skin channeling the fuel as part of a fuel system. Thus, the outer tube 12 represents a second skin channeling the fuel escaping unduly from the first skin.

The connection system 20 is provided with an internal connection device 30 for connecting the inner tube 11 to another member. This internal connection device 30 has a male connector 31 and a female connector 32 extending in a longitudinal direction X. The male connector 31 is sized to be plugged into the female connector 32 by being pushed in the longitudinal direction. In addition, the internal connection device 30 is provided with at least one internal seal 33 to seal 25 between the female connector 31 and the male connector 32. For this purpose, a circular inner groove 35 of revolution is formed in the male connector 31 or the female connector 32. An internal seal 33 is thus partially housed in the internal groove 35.

According to the example of FIG. 2, two circular internal grooves 35 of revolution are made on an external surface 36 of the male connector 31, this external surface 36 being opposite a female connector 32. Therefore, two seals In addition, the connection system 20 is also provided with an external connection device 40 for connecting the outer tube 12 of a double-skinned hose 10. This external connection device 40 has a first outer ring 41 secured to the outer tube 12 and a second outer ring 42. Therefore, the external connection device 40 is equipped with a clamping means 50 operable by an operator to fix the first outer ring 41 to the second outer ring 42.

According to the first embodiment of Figures 1 to 4, the clamping means 50 comprises a nut 51. The nut 51 is thus disposed around one of the outer rings. The nut 51 can slide longitudinally along this outer ring between two extreme positions for example.

Thus, the longitudinal displacement of the nut may be circumscribed on the one hand by a protuberance 41 'of a free end of an outer ring and, on the other hand, by the outer tube connected to a fixed end of this ring. external. The clamping means 50 then additionally includes a thread 42 'provided on one free end of the other outer ring. To fix the outer tube, an operator then moves the nut 51 against the protrusion 41 ', then screws the nut to the thread 42'.

Optionally, the external connection device 40 comprises an external sealing device such as an outer seal and / or a sealing strip placed on the thread 42 'cooperating with the nut 51. Such an outer seal may be placed between the nut 51 and the outer ring provided with the protrusion, and / or between the nut 51 and the outer ring without the protuberance, and / or the outer rings. According to the second embodiment of FIGS. 5 to 6, said external connection device 40 comprises a sleeve 70. The sleeve 70 cooperates with a clamping type clamping means 50 clamping this sleeve 70. According to this second embodiment of FIG. embodiment and with reference to Figure 5, each outer ring 41, 42 comprises at least one projection 44 circular revolution. Each protrusion extends from an outer ring to an external EXT medium to the tube 10. The sleeve 70 then encloses the projections 44 of the outer rings to secure an outer ring to the other outer ring, the sleeve 70 being tightened by minus one clamp 52. Optionally, the external connection device 40 comprises an external sealing device. This external sealing device may comprise at least one outer seal 45 disposed between each outer ring 41, 42 and the sleeve 70. For example, each outer ring has two circular projections defining longitudinally between them an external groove. An outer seal is then partially housed in the outer groove. Alternatively or additionally, the external sealing device may comprise at least one outer seal 46 which is arranged between the outer rings 41, 42.

Furthermore and with reference to Figure 6, the sleeve 70 advantageously includes two half-sleeves 71 to facilitate its implementation, the clamping collar 52 clamping the half-sleeves 71 against each other.

Independently of the embodiment and with reference to FIG. 2, the connection system 20 optionally comprises at least one spacer ring 60. This spacer ring 60 is intended to be interposed between the outer tube 12 and the inner tube 11. a double-skinned hose to maintain a minimum gap between these tubes. This spacer ring has a particular advantage when the inner and outer tubes are flexible, and therefore likely to deform. Each spacer ring 60 is then provided with a plurality of longitudinal flutes 61 so as not to obstruct the flow of fluid between the inner and outer tubes of a double-skinned hose. A spacer ring may be inserted for example between an inner tube and an outer tube, between an inner tube and the outer ring of an outer tube, between a male or female connector of an inner tube and the outer tube, or between a male or female connector of an inner tube and an outer ring of an outer tube. For connection to a reservoir and according to FIG. 1, a connection of the internal connection device 30 is secured to an inner tube 11 of a double skin pipe 10, in this case a male connector. The other connector is attached to the fuel line 4. In the example of Figure 1, the female connector is attached to the fuel line 4.

In addition, an outer ring of the external connection device 40 is attached to the outer tube of the pipe 10. A spacer ring may further be inserted between the inner tube 11 and the outer tube 12 of the pipe 1.

The other outer ring is integral with a plate fixed on the compartment 2, this other outer ring surrounding the connection attached to the fuel pipe 4. Thus, a spacer ring can be inserted between the other outer ring and the pipework. of fuel 4.

To secure the hose 10, an operator operates the hose to insert the male connector into the female connector. When the male connector is properly plugged into the female connector, the operator finalizes the installation by operating the clamping means. According to the first embodiment, the operator then tightens the nut 51. According to the second embodiment, the operator positions the sleeve 70 and clamps each clamp. With reference to FIG. 3, a hydraulic circuit may comprise two double-skinned pipes to be connected to each other. A first pipe 10 thus has a first inner tube 11 which is housed in a first outer tube 12. The second pipe 15 has a second inner tube 16 which is housed in a second outer tube 17. Therefore, the internal connection device 30 comprises a male connector 31 secured to the first inner tube 11, and a female connector 32 secured to the second inner tube 16. At least one inner seal 33 seals between the male connector 31 and the female connector 32, and in particular two seals in FIG.

The external connection device 40 is provided with a first outer ring 41 secured to the first outer tube 12 and a second outer ring 42 secured to the second outer tube 17. In addition, the external connection device 40 is provided with a clamping means 50. To connect the first pipe 10 to the second pipe 15, an operator operates these pipes to insert the male connector into the female connector. When the male connector is properly plugged into the female connector, the operator finalizes the installation by operating the clamping means. According to the first embodiment, the operator then tightens the nut 51. According to the second embodiment, the operator positions the sleeve 70 and clamps each clamp. Naturally, the present invention is subject to many variations as to its implementation. Although several embodiments have been described, it is well understood that it is not conceivable to exhaustively identify all the possible modes. It is of course conceivable to replace a means described by equivalent means without departing from the scope of the present invention.

Claims (11)

REVENDICATIONS1. System (20) for sealing a double-skinned pipe (10) having an inner tube (11) housed in an outer tube (12), characterized in that said system (20) is provided with: an internal connecting device (30) for connecting the inner tube (11) provided on the one hand with a male connector (31) and a female connector (32) extending in a longitudinal direction (X), said male connector (31) being insertable into said female connector (32) in the longitudinal direction, and secondly at least one inner seal (33) sealing between said male connector (31) and said female connector (32), one of said connectors (31) being securable to said inner tube (11), - an external connecting device (40) for connecting the outer tube (12) provided with a first outer ring (41) and a second outer ring (42), said external connecting device (40) having a clamping means (50) for connecting the first ring external (41) to the second outer ring (42), one of said outer rings (41, 42) being securable to said outer tube (12). 2. System according to claim 1, characterized in that this system (20) comprises at least one spacer ring (60) intended to be interposed between the outer tube (12) and the inner tube (11), said ring spacer (60) having a plurality of longitudinal splines (61) for fluid passage through said spacer ring (60). 3. System according to any one of claims 1 to 2, characterized in that said internal connection device (30) comprises at least one inner circular groove (35) of revolution formed in at least one of said male connectors (31) and female (32), said inner seal (33) being partially housed in said internal groove (35). 4. System according to claim 3, characterized in that said internal connection device (30) comprises at least one inner circular groove (35) of revolution formed in an outer surface (36) of said male connector (31) facing said connector female (32), said inner seal (33) being housed in said internal groove (35). 5. System according to any one of claims 1 to 4, characterized in that said clamping means (50) comprises a nut (51) disposed around one of said first and second outer rings (41) and being locked longitudinally by at least one protrusion (41 ') of this outer ring (41), said nut (51) being screwable to a thread (42') of the other outer ring (42). 6. System according to any one of claims 1 to 4, characterized in that each outer ring (41, 42) comprises at least one projection (44) circular revolution directed towards a medium (EXT) external to the pipe (10). , said external connecting device (40) having a sleeve (70) enclosing said circular projections (44), said clamping means (50) comprising at least one clamp (52) clamping said sleeve (70). 7. System according to claim 6, characterized in that said sleeve (70) comprises two half-sleeves (71), said clamping collar (52) clamping said half-sleeves (71) against each other. 8. System according to claim 6, characterized in that at least one outer seal (45) is disposed between each outer ring (41, 42) and said sleeve (70). 9. System according to any one of claims 6 to 8, characterized in that at least one outer seal (46) is disposed between the outer rings (41, 42). 10. Hydraulic circuit (5) provided with a first pipe (10) comprising a first inner inner tube (11) housed in a first outer tube (12), characterized in that said circuit (5) comprises a system (20) sealing connection according to any one of claims 1 to 9 for connecting the first pipe (10), this system (20) being provided with: - an internal connection device (30) provided with a male connector (31) ) and a female connector (32) extending in a longitudinal direction (X), said male connector (31) being insertable into said female connector (32) in the longitudinal direction (X), at least one joint internal seal (33) sealing between said male connector (31) and said female connector (32), one of said connectors (31) being secured to said first inner tube (11), - a connecting device outer member (40) provided with a first outer ring (41) and a second outer ring (42), one of said outer rings ( 41, 42) attachable to said inner tube (11), said external disconnecting device (40) having a clamping means (50) for connecting the first outer ring (41) to the second outer ring (42). 11. Circuit (5) according to claim 10, characterized in that this circuit (5) comprising a second pipe (15) having a second inner tube (16) housed in a second outer tube (17): - said male connector ( 31) is secured to an inner tube (11) and said female connector (32) is secured to the other inner tube (16), - the first outer ring (41) is secured to the first outer tube (12) and the second outer ring (42) is secured to the second outer tube (17).