Connection pipe for aircraft tank and tank comprising at least one such pipe

Abstract

The invention relates to a connection tube (2) for an aircraft tank, the tube (2) comprising a base (20) intended to be fixed to a tank wall (1), a connection part (22) comprising a through conduit (220) for the passage of a fluid, the connection part (22) being connected to the base (20) by a deformable connecting part (24), the connecting part (24) comprising at least one fold (26) forming a projection from a first surface (200) of the base (20) and configured to deform to allow movement of the connection part (22) relative to the base (20), the fold(s) (26) being configured to delimit a path (C) allowing a fluid to flow from the first surface (200) of the base (20) to the through conduit (220) of the connection part (22). Figure 4.

Description

Title of the invention: Connection tube for aircraft tank and tank comprising at least one such tube Technical field

[0001] The present invention relates to the field of aeronautics. It relates more particularly to a connection tube for an aircraft tank, such as a flexible tank on board a helicopter. State of the art

[0002] Aircrafts have one or more tanks for storing fluids necessary for the operation of their engines. These may be fuel tanks or lubricant tanks. An aircraft tank has connection pipes for transferring the fluid contained therein to the outside of the tank and pipes for venting the tank, i.e., in particular, extracting the air present in the tank when it is being filled.

[0003] Some tubing is said to be extensible. This is the case, for example, of the tubing equipping the flexible tanks found on board certain helicopters. A known ventilation tubing is shown in [Fig. 1]. Such a tubing comprises a base B and a tubular part T, intended to be connected to a connection element. The tubular part T is connected to the base B by a deformable part D formed by flexible folds and making it possible to obtain axial movement of the tubular part T (the latter being able, by deformation of the folds of the deformable part D, to move along its longitudinal axis in the direction of the arrow F), and angular movement of the tubular part T (the latter being able to move angularly on either side of its longitudinal axis, also by deformation of the folds of the deformable part D). When the tubing of [Fig.l] is installed in the upper part of a tank (the free end of the tubular part T then being directed upwards, as shown in [Fig.l]), the difference in height H between the base B and the lower end of the deformable part D has the effect of trapping a layer of air located against the upper wall of the tank, at a height close to the height H. This volume of air therefore penalizes the optimal filling of the tank, since the volume occupied cannot be occupied by fuel or lubricant.

[0004] Furthermore, the design of known drainage pipes, similar to that of the ventilation pipe of [Fig.l], also generates disadvantages. Indeed, the folds of the deformable part define a space around the tubular part, which when the pipe is installed in the lower part of a fuel tank, cannot be emptied when draining the fuel. So, when the tank is empty, fuel stagnates in this space, which is best avoided.

[0005] The objective of the present invention is to propose an extensible tube making it possible to overcome the drawbacks of the state of the art, and in particular the drawbacks described above. Statement of the invention

[0006] For this purpose, the invention relates to a connection tube for an aircraft tank, the tube comprising a base intended to be fixed to a tank wall, a connection part comprising a through conduit for the passage of a fluid, the connection part being connected to the base by a deformable connecting part, the connecting part comprising at least one fold forming a projection from a first surface of the base and configured to deform to allow movement of the connection part relative to the base, the fold(s) being configured to delimit a path allowing a fluid to flow from the first surface of the base to the through conduit of the connection part.

[0007] Thus, by providing a configuration of the fold(s) of the connecting portion which defines a path allowing a fluid to flow, without encountering obstacles, from the first surface of the base to the through conduit of the connecting portion, it is ensured that no quantity of fluid can remain trapped inside a tank due to the shape of the tubing. In the case of a ventilation tubing, all of the air contained in the tank will be free to escape, thus avoiding creating a dead volume within the tank. In the case of a drainage tubing, no quantity of fuel or lubricant risks remaining trapped and stagnating within the tank.

[0008] In one embodiment, the tubing comprises at least two folds of generally circular shape centered around a central axis of the tubing, the folds being concentric and spaced apart, each fold being interrupted by at least one passage zone allowing a fluid to pass through the corresponding fold.

[0009] In one embodiment, each fold has a section of evolving height, the height being minimal at the level of the corresponding passage zone, and maximal at the level of a part of the fold diametrically opposite the passage zone.

[0010] In one embodiment, the passage zones of two adjacent folds are diametrically opposed.

[0011] In one embodiment, the tubing comprises at least one fold of generally spiral shape, the fold extending between a first end and a second end, forming one or more non-contiguous turns around the conduit passing through the connection part.

[0012] In one embodiment, the fold has a height relative to the first surface of the base which is zero or almost zero at each of the first and second ends, the height of the fold increasing from each of the first and second ends to reach a maximum height at least at an intermediate portion located between the first and second ends.

[0013] In one embodiment, the spiral formed by the fold comprises between 1 and 2 turns, and for example 1.5 or 2 turns.

[0014] In one embodiment, the tubing comprises a single fold of generally spiral shape.

[0015] In one embodiment, the fold(s) are configured to allow axial movement of the connection portion, along a central axis of the tubing, and / or angular movement relative to the central axis of the tubing.

[0016] In one embodiment, the axial displacement travel of the connection part is between 50 and 100 mm, and preferably between 70 and 80 mm.

[0017] In one embodiment, the angular movement of the connection part is between 60° and 120°, and preferably greater than or equal to 90°.

[0018] In one embodiment, the tubing is either a ventilation tubing whose connection part is tubular in shape with an axis coincident with a central axis of the tubing, or a drainage tubing whose connection part is annular in shape with an axis coincident with a central axis of the tubing.

[0019] The invention also relates to a tank for an aircraft, in particular a flexible tank, comprising at least one tube as defined above, the tube being fixed to a lower wall or to an upper wall of the tank.

[0020] The invention also relates to an aircraft comprising at least one tank conforming to that defined above. Brief description of the drawings

[0021] [Fig-1] [Fig.l], already described, is a perspective view of a known tubing.

[0022] [Fig.2] [Fig.2] is a perspective view of a tank equipped with connection pipes in accordance with the invention.

[0023] [Fig.3] [Fig.3] is a top view showing a drainage tube according to the invention.

[0024] [Fig.4] [Fig.4] is a perspective view of the tubing of [Fig.3].

[0025] [Fig.5] [Fig.5] is a sectional view in plane AA of [Fig.3].

[0026] [Fig.6] [Fig.6] is a view similar to [Fig.5], showing the tubing in a extension position.

[0027] [Fig.7] [Fig.7] is a top view showing a ventilation tube according to the invention.

[0028] [Fig.8] [Fig.8] is a perspective view of the tubing of [Fig.7].

[0029] [Fig.9] [Fig.9] is a perspective view of the tubing of [Fig.7] showing the first surface of the base.

[0030] [Fig. 10] [Fig. 10] is a sectional view in plane AA of [Fig.7].

[0031] [Fig.11] [Fig.11] is a view similar to [Fig.10], showing the tubing in a extension position.

[0032] [Fig. 12] [Fig. 12] is a top view showing a ventilation manifold according to the invention.

[0033] [Fig.13] [Fig.13] is a perspective view of the tubing of [Fig.12].

[0034] [Fig. 14] [Fig. 14] is a perspective view of the tubing of [Fig. 12] showing the first surface of the base.

[0035] [Fig. 15] [Fig. 15] is a sectional view in plane AA of [Fig. 12].

[0036] [Fig. 16] [Fig. 16] is a view similar to [Fig. 15], showing the tubing in a extension position.

[0037] [Fig. 17] [Fig. 17] is a top view showing a drainage tube according to the invention.

[0038] [Fig. 18] [Fig. 18] is a perspective view of the tubing of [Fig. 17].

[0039] [Fig. 19] [Fig. 19] is a sectional view in plane AA of [Fig. 17].

[0040] [Fig.20] [Fig.20] is a top view showing a drainage tubing in accordance with the invention.

[0041] [Fig.21] [Fig.21] is a perspective view of the tubing of [Fig.20].

[0042] [Fig.22] [Fig.22] is a sectional view in plane AA of [Fig.20]. Detailed description

[0043] [Fig. 2] represents a tank 1 equipped with connection pipes 2 according to the invention. In the example, the tank 1 is a flexible fuel tank for a helicopter, but the connection pipes according to the invention can be fitted to all types of aircraft tank. In the example of [Fig. 2], the tank 1 comprises two drainage pipes 2, arranged in the lower part of the tank 1 and fixed to a lower wall 10 thereof, and two ventilation pipes 2, arranged in the upper part of the tank 1 and fixed to an upper wall 12 thereof.

[0044] Figures 3 to 6 illustrate a first example of tubing 2 according to the invention, forming a drainage tubing.

[0045] As visible in [Fig. 3], which is a top view, the tubing 2 comprises a base 20 intended to be fixed to a tank wall, in the example the lower wall 10 of the tank 1 of [Fig. 2]. The base 20 advantageously has a symmetrical shape of revolution around a central axis X of the tubing, in the example an annular shape. The tubing 2 comprises a connection part 22, intended to be connected to a connection element, in the example an annular connector 3a. The connection part 22 comprises a through conduit 220 for the passage of a fluid, centered around an axis coincident with the central axis X. The through conduit 220 passes through the connection part 22 and therefore the tubing 2. Thus, the through conduit 220 opens, on the one hand, on the side of a first surface 200 of the base 20, intended in the example to be oriented towards the interior of the tank 1 when the tubing is in the operating configuration, and, on the other hand, on the side of a second surface 202 of the base 20 opposite the first surface 200. Thus, when the tubing 2 is in the operating configuration, the through conduit 220 is capable of putting the interior of the tank 1 into fluid communication with any (external) pipe connected to the tubing 2. The annular connector 3a comprises a through conduit 30 centered around an axis coincident with the central axis X and which is in fluid communication with the through conduit 220 of the tubing 2.

[0046] The connection part 22 is connected to the base 20 via a deformable connecting part 24. The connecting part 24 comprises for this purpose at least one deformable fold 26, the or each fold 26 forming a projection from the first surface 200 of the base 20. In the example, the or each fold 26 has a “U”-shaped section (inverted “U” shape in the examples of FIGS. 3 to 6), the branches of the “U” being connected to the first surface 200 of the base 20. Advantageously, the height of the or one fold 26 is not constant over the entire fold, and is scalable over at least a portion of the or each fold, as detailed below.

[0047] In the example of Figures 3 to 6, the tubing 2 comprises two folds 26 of generally circular shape, the two folds being concentric and spaced apart from each other (each fold 26 being centered around the central axis X). Each fold 26 is interrupted over at least part of its contour by a passage zone 260 allowing the passage of a fluid. Thus, each passage zone 260 constitutes a gap in the corresponding fold 26, allowing a fluid to pass through this fold 26. The connecting part 24 has, at the level of each passage zone 260, a zero or almost zero height relative to the first surface 200 of the base 20. As can be seen in particular in [Fig.4], the passage zones 260 make it possible to define, with the folds 26, a path C allowing a fluid (such as a fuel or a lubricant) to flow from the first surface 200 of the base 20 towards the through conduit 220 without encountering obstacles, and therefore without risk of being trapped in a part of the tubing 2 and stagnating there. More precisely, the fluid is likely to take the path C, this path first passing through the passage zone 260 of the first fold 26, or outer fold, then passing around the second fold 26, or inner fold, and finally passing through the passage zone 260 of the second fold 26 to reach the through conduit 220.

[0048] In the example, the height of each fold 26 increases regularly from the corresponding passage zone 260 to a diametrically opposite part having a maximum height hm, identical for the two folds 26. The passage zones 260 of each fold 26 are preferably diametrically opposite, so that the parts of maximum height are also diametrically opposite, thus allowing better travel of the connection part 22, as visible in FIGS. 5 and 6, since the travel of the connection part is directly dependent on the height of the folds 26.

[0049] Figures 5 and 6 are sectional views along plane AA of [Fig. 3], respectively in a normal configuration and an extended configuration of the tubing 2. As seen in [Fig. 5], in the normal configuration of the tubing 2, the connection portion 22 is in a normal position, or retracted position. In the example, the connection portion 22, which has an annular shape, is, in its normal position, located substantially at the same level as the base 20. The connection portion 22 may, however, not be located at the same level as the base 20. Furthermore, in the normal configuration of the tubing 2, the folds 26 have their normal shape, or retracted shape. In the extended configuration of the tubing 2, the connection portion 22 is in an extended position. The connection portion 22 moves from its normal position ([Fig. 5]) to its extended position ([Fig.6]) by an axial movement, in a direction substantially parallel to the central axis X, away from the base 20, and more precisely in a direction opposite to the orientation of the first surface 200 of the base 20 (direction indicated by the arrow F). As visible in [Fig. 6], this extension movement, of travel c, is permitted by the deformation of the connecting part 24, and more particularly of the folds 26, these being at least partially extended to allow the movement of the connection part 22. The deformation of the connecting part 24 also allows an angular movement of the connection part 22 relative to the central axis X, whether the connection part 22 is in its normal position or in its extended position. As shown in [Fig. 5], the connecting part 24 allows an angular movement of the connection part 22 relative to the central axis X by an angle equal to twice the angle a.

[0050] Figures 7 to 11 illustrate a second example of tubing 2 according to the invention, forming a ventilation tubing.

[0051] As can be seen in [Fig.7], which is a top view, the tubing 2 comprises, like the tubing of figures 3 to 6, a base 20, a connection part 22 and a connecting part 24. The base 20 is intended to be fixed to a tank wall, in the example the upper wall 12 of the tank 1 of [Fig.2]. The connection part 22 is in the example of tubular shape. It is also intended to be connected to a connection element, in the example a tubular connector 3b. The tubular connector 3b comprises a through conduit 30 centered around an axis coincident with the central axis X.

[0052] As visible in Figures 7 to 11, the connecting part 24 comprises two folds 26 of a configuration similar to the folds 26 of Figures 3 to 6. Thus, the folds 26 form a projection from the first surface 200 of the base 20, and delimit a path C (Figures 7, 9) allowing a fluid to flow in a manner similar to that described in relation to the previous embodiment. As this is a ventilation tube arranged in the upper part of a tank, the path C facilitates the evacuation of gas, in particular air when it is expelled from the tank when it is filled.

[0053] As visible in Figures 10 and 11, which are sectional views along the plane AA of [Fig.7], respectively in the normal configuration and the extension configuration of the tubing 2, the connection part 22 can, as described previously, be moved into its extension position thanks to the deformation of the connecting part 24. As described previously, the deformation of the connecting part 24 also allows an angular movement of an angle α of the connection part 22 relative to the central axis X, whether the connection part 22 is in its normal position or in its extension position.

[0054] Figures 12 to 16 illustrate a third example of tubing 2 according to the invention, forming a ventilation tubing.

[0055] The tubing 2 shown in Figures 12 to 16 differs from the tubing of Figures 7 to 11 by the configuration of its connecting part 24. Indeed, as visible in [Fig. 12], which represents the tubing 2 seen from above, and in Figures 13 and 14, which represent the tubing 2 seen in perspective, the tubing 2 comprises a single fold 26 of general spiral shape. Thus, the fold 26 extends between a first end 261, or inner end, and a second end 262, or outer end, forming one or more turns (not touching) of a spiral extending around the through conduit 220 of the connection part 22. This spiral configuration of the fold 26 makes it possible, as for the previous examples of tubing in accordance with the invention, to define a path C allowing a fluid to flow from the first surface 200 of the base 20 towards the through conduit 220 without encountering any obstacles.The fluid can follow path C (Figures 12 and 14), which first passes between the second end 262 of the fold 26 and the adjacent turn of the fold 26, then passes within the space located between the turns formed by the fold 26, to the through conduit 220.

[0056] As can be seen in Figures 15 and 16, which are sectional views along plane AA of [Fig. 12], respectively in the normal configuration and the extension configuration of the tubing 2, the connection part 22 can, as previously described, be moved into its extension position thanks to the deformation of the connecting portion 24. As previously described, the deformation of the connecting portion 24 also allows angular movement of an angle α of the connecting portion 22 relative to the central axis X, whether the connecting portion 22 is in its normal position or in its extended position.

[0057] In the example of Figures 12 to 16, the fold 26 extends between the first end 261 and the second end 262 so as to form a spiral comprising 1.5 turns. The number of turns may be different, for example equal to two as detailed below. Preferably the number of turns is greater than or equal to 1.

[0058] Advantageously, the fold 26 has a cross-section in the shape of an inverted “U” similar to that described above. Advantageously, the fold 26 has a zero or almost zero height at each of the first and second ends 261, 262, and comprises an evolving cross-section having a maximum height hm at least at an intermediate part located between the first and second ends 261, 262. Thus, the curve followed by the free end of the fold 26 forms on a first part an ascending helical spiral and on a second part a descending helical spiral.

[0059] Figures 17 to 19 illustrate a fourth example of tubing 2 according to the invention, forming a drainage tubing.

[0060] The tubing 2 of figures 17 to 19 is a drainage tubing similar to the tubing of figures 3 to 6, but comprising a spiral-shaped fold 26 similar to the fold of figures 12 to 16.

[0061] Figures 20 to 22 illustrate a fifth example of tubing 2 according to the invention, forming a drainage tubing.

[0062] The tubing 2 of figures 20 to 22 is a drainage tubing similar to the tubing of figures 17 to 19, with the difference that the spiral formed by the fold 26 has two turns.

[0063] Advantageously, for all the examples of tubing according to the invention described above, the connecting part 24 will be configured to allow axial movement of the connection part 22, i.e. the travel c of the connection part 22 between its normal position and its extended position, which is greater than or equal to 50 mm. Preferably, the axial movement is between 50 and 100 mm, or between 70 and 80 mm. Furthermore, the connecting part 24 will be configured to allow angular movement of the connection part 22, i.e. the total angular travel of the connection part in a plane comprising the axis X (therefore corresponding to twice the value of the angle a), which is greater than or equal to 30°, and preferably greater than or equal to 60°. Preferably, the angular movement will be between 60° and 120°, and for example close to or equal to 90°.

[0064] It is specified that the pipes described above as being arranged in the upper part of a tank may in certain applications be arranged in the lower part of a tank. Similarly, the pipes described above as being arranged in the lower part of a tank may in certain applications be arranged in the upper part of a tank.

[0065] The tubing according to the invention can advantageously be produced by assembly or by molding, for example from an elastomer material or a reinforced elastomer material.

Claims

Claims

1. Connection tubing (2) for a tank (1) for an aircraft, the tubing (2) comprising a base (20) intended to be fixed to a wall (10, 12) of the tank (1), a connection part (22) comprising a through conduit (220) for the passage of a fluid, the connection part (22) being connected to the base (20) by a deformable connecting part (24), the connecting part (24) comprising at least one fold (26) forming a projection from a first surface (200) of the base (20) and configured to deform to allow movement of the connection part (22) relative to the base (20), the fold(s) (26) being configured to delimit a path (C) allowing a fluid to flow from the first surface (200) of the base (20) to the through conduit (220) of the connection part (22) connection (22).

2. Tubing (2) according to the preceding claim, comprising at least two folds (26) of generally circular shape centered around a central axis (X) of the tubing (2), the folds (26) being concentric and spaced apart, each fold (26) being interrupted by at least one passage zone (260) allowing a fluid to pass through the corresponding fold (26).

3. Tubing (2) according to the preceding claim, in which each fold (26) has a section of varying height, the height being minimal at the level of the corresponding passage zone (260), and maximal at the level of a part of the fold (26) diametrically opposite the passage zone (260).

4. Tubing (2) according to the preceding claim, in which the passage zones (260) of two adjacent folds (26) are diametrically opposite.

5. Tubing (2) according to claim 1, comprising at least one fold (26) of generally spiral shape, the fold (26) extending between a first end (261) and a second end (262) forming one or more non-joining turns around the through conduit (220) of the connection part (22).

6. Tubing (2) according to the preceding claim, in which the fold (26) has a height relative to the first surface (200) of the base (20) which is zero or almost zero at each of the first and second ends (261, 262), the height of the fold (26) increasing from each of the first and second ends (261, 262) to reach a maximum height (hm) at least at an intermediate portion located between the first and second ends (261, 262).

7. Tubing (2) according to one of claims 5 and 6, in which the spiral formed by the fold (26) comprises between 1 and 2 turns, and for example 1.5 or 2 turns.

8. Tubing (2) according to one of the preceding claims, in which the fold(s) (26) are configured to allow axial displacement of the connection part (22), along a central axis (X) of the tubing (2), and / or angular displacement relative to the central axis (X) of the tubing (2).

9. Tubing (2) according to the preceding claim, in which the axial displacement travel of the connection part (22) is between 50 and 100 mm, and preferably between 70 and 80 mm, and / or in which the angular movement of the connection part (22) is between 60° and 120°, and preferably greater than or equal to 90°.

10. Tank (1) for aircraft, comprising at least one tube (2) according to one of the preceding claims, the tube (2) being fixed to a lower wall (10) or to an upper wall (12) of the tank (1).

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