Connecting pipe for aircraft tank and tank including at least one such pipe

Abstract

The invention relates to a connecting pipe (2) for an aircraft tank, the pipe (2) comprising a base (20) for attachment to a tank wall (1), a connecting portion (22) comprising a through-conduit (220) for the passage of a fluid, the connecting portion (22) being connected to the base (20) by a deformable connecting portion (24), the connecting portion (24) comprising at least one fold (26) projecting from a first surface (200) of the base (20) and configured to deform to allow displacement of the connecting portion (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 connecting portion (22). Figure 4.

Description

Title of the invention: Connecting pipe for aircraft tank and tank comprising at least one such pipe. Technical field

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

[0002] Aircraft 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 connecting pipes for transferring the fluid contained within to the outside of the tank and pipes for venting the tank, that is to say, in particular, the extraction of air present in the tank during its filling.

[0003] Some tubing is said to be extensible. This is the case, for example, with the tubing used in the flexible tanks found on board some helicopters. A known ventilation tube is shown in [Fig. 1]. Such a tube has a base B and a tubular portion T, intended to be connected to a connecting element. The tubular portion T is connected to the base B by a deformable portion D formed by flexible folds, allowing axial movement of the tubular portion T (which, by deformation of the folds of the deformable portion D, can move along its longitudinal axis in the direction of arrow F), and angular movement of the tubular portion T (which can move angularly on either side of its longitudinal axis, also by deformation of the folds of the deformable portion D). When the tube 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, over a height close to the height H. This volume of air therefore penalizes the optimal filling of the tank, since the occupied volume cannot be filled by fuel or lubricant.

[0004] Furthermore, the design of known drainage pipes, analogous to that of the ventilation pipe in [Fig. 1], also generates drawbacks. 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. during fuel drainage. Thus, 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 that overcomes the disadvantages of the prior art, and in particular the disadvantages described above. Description of the invention

[0006] For this purpose, the invention relates to a connecting tube for an aircraft tank, the tube comprising a base intended to be fixed to a tank wall, a connecting part comprising a through conduit for the passage of a fluid, the connecting 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 a displacement of the connecting 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 connecting part.

[0007] Thus, by providing a configuration for the fold(s) of the connecting section that 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 section, it is ensured that no fluid can remain trapped inside a tank due to the shape of the tubing. In the case of a venting tube, all the air contained in the tank will be free to escape, thus preventing the creation of a dead volume within the tank. In the case of a draining tube, no fuel or lubricant is likely to become trapped and stagnate within the tank.

[0008] In one embodiment, the tubing has at least two folds of general 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 maximum at the level of a part of the fold diametrically opposite to the passage zone.

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

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

[0015] In one embodiment, the fold(s) are configured to allow axial displacement of the connecting part along a central axis of the tubing, and / or angular displacement with respect to the central axis of the tubing.

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

[0017] In one embodiment, the angular deflection of the connecting 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 connecting part is tubular in shape with an axis coinciding with a central axis of the tubing, or a drainage tubing whose connecting part is annular in shape with an axis coinciding with a central axis of the tubing.

[0019] The invention also relates to an aircraft tank, in particular a flexible tank, comprising at least one tube as defined above, the tube being fixed to a lower or 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] The [Fig.1], already described, is a perspective view of a known tube.

[0022] [Fig.2] Fig.2 is a perspective view of a tank equipped with connecting pipes according to the invention.

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

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

[0025] [Fig.5] The [Fig.5] is a cross-sectional view in plane AA of the [Fig.3].

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

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

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

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

[0030] [Fig. 10] The [Fig. 10] is a cross-sectional view in plane AA of the [Fig.7].

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

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

[0033] [Fig.13] The [Fig.13] is a perspective view of the tubing of the [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] The [Fig. 15] is a cross-sectional view in plane AA of the [Fig. 12].

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

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

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

[0039] [Fig. 19] The [Fig. 19] is a cross-sectional view in plane AA of the [Fig. 17].

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

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

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

[0043] Figure 2 shows a tank 1 equipped with connecting pipes 2 according to the invention. In the example, the tank 1 is a flexible fuel tank for a helicopter, but the connecting pipes according to the invention can be fitted to all types of aircraft tanks. In the example of Figure 2, the tank 1 has two drain pipes 2, located in the lower part of the tank 1 and attached to a lower wall 10 thereof, and two vent pipes 2, located in the upper part of the tank 1 and attached 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 can be seen in [Fig. 3], which is a top view, the tube 2 has a base 20 for being fixed to a tank wall, in this example the lower wall 10 of the tank 1 in [Fig. 2]. The base 20 advantageously has a symmetrical shape of revolution about a central axis X of the tube, in this example an annular shape. The tube 2 has a connecting portion 22 for being connected to a connecting element, in this example an annular fitting 3a. The connecting section 22 includes a through-conduit 220 for the passage of a fluid, centered around an axis coinciding with the central axis X. The through-conduit 220 passes through the connecting section 22 and therefore through the pipe 2. Thus, the through-conduit 220 opens, on one side, onto a first surface 200 of the base 20, intended in this example to be oriented towards the interior of the tank 1 when the pipe is in its operating configuration, and, on the other side, onto a second surface 202 of the base 20 opposite the first surface 200. Thus, when the pipe 2 is in its operating configuration, the through-conduit 220 is capable of establishing fluid communication between the interior of the tank 1 and any (external) pipe connected to the pipe 2. The annular fitting 3a includes a through-conduit 30 centered around an axis coinciding with the central axis X. and which is in fluidic communication with the conduit traversing 220 of the tubing 2.

[0046] The connecting portion 22 is connected to the base 20 via a deformable linking portion 24. The linking portion 24 comprises, for this purpose, at least one deformable fold 26, the fold or folds 26 projecting from the first surface 200 of the base 20. In the example, the fold or folds 26 have a U-shaped cross-section (an inverted U-shape in the examples of Figures 3 to 6), the arms of the U being connected to the first surface 200 of the base 20. Advantageously, the height of the fold or folds 26 is not constant along the entire fold, and varies over at least a portion of the fold or folds, as detailed below.

[0047] In the example of Figures 3 to 6, the tubing 2 has two folds 26 of generally circular shape, the two folds being concentric and spaced apart (each fold 26 being centered around the central axis X). Each fold 26 is interrupted on at least part of its contour by a passage zone 260 allowing the passage of a fluid. Thus, each passage zone 260 constitutes a breach 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 height of zero or almost zero with respect to the first surface 200 of the base 20. As can be seen in particular in [Fig.[4] The flow zones 260, together with the folds 26, define a path C allowing a fluid (such as a fuel or lubricant) to flow from the first surface 200 of the base 20 to 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 path C, this path first passing through the flow 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 flow zone 260 of the second fold 26 to reach the through conduit 220.

[0048] In the example, the height of each fold 26 is regularly increasing from the corresponding passage zone 260 to a diametrically opposite part having a maximum height hm, identical for both 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 a better deflection of the connecting part 22, as seen in figures 5 and 6, since the stroke of the connecting part is directly dependent on the height of the folds 26.

[0049] Figures 5 and 6 are cross-sectional views along plane AA of [Fig. 3], respectively in a normal and an extended configuration of the tubing 2. As can be seen in [Fig. 5], in the normal configuration of the tubing 2, the connecting portion 22 is in its normal, or retracted, position. In the example, the connecting portion 22, which has an annular shape, is, in its normal position, located substantially at the same level as the base 20. The connecting 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 are in their normal, or retracted, shape. In the extended configuration of the tubing 2, the connecting portion 22 is in an extended position. The connecting portion 22 moves from its normal position ([Fig. 5]) to its extended position ([Fig. 6]).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 arrow F). As seen in [Fig. 6], this extension movement, of stroke c, is made possible by the deformation of the connecting part 24, and more particularly of the folds 26, these being at least partially extended to allow the displacement of the connecting part 22. The deformation of the connecting part 24 also allows an angular movement of the connecting part 22 with respect to the central axis X, whether the connecting part 22 is in its normal position or in its extended position. As shown in [Fig. 5], the connecting part 24 allows an angular displacement of the connecting part 22 with respect to the central axis X of 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, like the tubing in Figures 3 to 6, comprises a base 20, a connecting portion 22, and a connecting portion 24. The base 20 is intended to be fixed to a tank wall, in this example the upper wall 12 of tank 1 in [Fig. 2]. The connecting portion 22 is tubular in shape in this example. It is also intended to be connected to a connecting element, in this example a tubular fitting 3b. The tubular fitting 3b includes a through conduit 30 centered around an axis coinciding with the central axis X.

[0052] As can be seen in Figures 7 to 11, the connecting portion 24 has two folds 26 with a configuration similar to the folds 26 in Figures 3 to 6. Thus, the folds 26 project from the first surface 200 of the base 20 and define a path C (Figures 7, 9) allowing a fluid to flow in a manner similar to that described in relation to the previous embodiment. Since this is a ventilation pipe located at the top of a tank, the path C facilitates the evacuation of gases, in particular air when it is expelled from the tank during its filling.

[0053] As can be seen in Figures 10 and 11, which are cross-sectional views along plane AA of [Fig.7], respectively in the normal and extended configurations of the tubing 2, the connecting part 22 can, as described previously, be moved into its extended position by deformation of the connecting part 24. As also described previously, the deformation of the connecting part 24 also allows an angular movement of an angle α of the connecting part 22 with respect to the central axis X, whether the connecting part 22 is in its normal position or in its extended 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 in Figures 7 to 11 by the configuration of its connecting part 24. Indeed, as can be seen in [Fig.12], which shows tubing 2 viewed from above, and in Figures 13 and 14, which show tubing 2 viewed in perspective, tubing 2 has 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 contiguous) of a spiral extending around the conduit 220 through the connecting part 22. This spiral configuration of the fold 26 allows, as for the previous examples of tubing according to the invention, to define a path C allowing a fluid to flow from the first surface 200 of the base 20 towards the conduit 220 through without encountering obstacles.The fluid can follow path C (figures 12 and 14), which passes first between the second end 262 of the fold 26 and the adjacent turn of the fold 26, then passes within the space between the turns formed by the fold 26, up to the conduit through 220.

[0056] As can be seen in Figures 15 and 16, which are cross-sectional views along plane AA of [Fig. 12], respectively in the normal and extended configurations of the tubing 2, the connecting part 22 can, as described above, be moved into its extended position by means of 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 a of the connecting part 22 with respect to the central axis X, whether the connecting part 22 is in its normal position or in its extended position.

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

[0058] Advantageously, the fold 26 has an inverted U-shaped cross-section analogous to that described above. Advantageously, the fold 26 has a zero or near-zero height at each of the first and second ends 261, 262, and has 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 an ascending helical spiral in a first part and a descending helical spiral in a second part.

[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 having 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] Tubing 2 in Figures 20 to 22 is a drainage tubing similar to tubing in Figures 17 to 19, except that the spiral formed by the fold 26 has two turns.

[0063] Advantageously, for all examples of tubing according to the invention described above, the connecting portion 24 will be configured to allow an axial deflection of the connecting portion 22, i.e., the stroke c of the connecting portion 22 between its normal position and its extended position, which is greater than or equal to 50 mm. Preferably, the axial deflection is between 50 and 100 mm, or between 70 and 80 mm. Furthermore, the connecting portion 24 will be configured to allow an angular deflection of the connecting portion 22, i.e., the total angular stroke of the connecting portion in a plane including the X-axis (corresponding therefore to twice the value of angle a), which is greater than or equal to 30°, and preferably greater than or equal to 60°. Preferably, the angular deflection 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 located in the upper part of a tank may, in certain applications, be located in the lower part of a tank. Similarly, the pipes described above as being located in the lower part of a tank may, in certain applications, be located in the upper part of a tank.

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

Claims

Demands

1. Connecting pipe (2) for an aircraft tank (1), the pipe (2) having a base (20) for attachment to a tank wall (10, 12), a connecting portion (22) having a through-conduit (220) for the passage of a fluid, the connecting portion (22) being connected to the base (20) by a deformable connecting portion (24), the connecting portion (24) having at least one fold (26) projecting from a first surface (200) of the base (20) and configured to deform to allow displacement of the connecting portion (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 connecting portion (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, wherein each fold (26) has a section of evolving height, the height being minimal at the level of the corresponding passage zone (260), and maximum at the level of a part of the fold (26) diametrically opposite the passage zone (260).

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

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-contiguous turns around the conduit through (220) of the connecting part (22).

6. Tubing (2) according to the preceding claim, wherein 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 extremities (261, 262) to reach a maximum height (hm) at least at the level of an intermediate part located between the first and second extremities (261, 262).

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

8. Tubing (2) according to any one of the preceding claims, wherein the fold(s) (26) are configured to permit axial displacement of the connecting part (22), along a central axis (X) of the tubing (2), and / or angular displacement with respect to the central axis (X) of the tubing (2).

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

10. Aircraft tank (1), comprising at least one tube (2) according to any 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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