Fuel storage device, an aircraft, and a method

Abstract

A fuel storage device (10) having at least one tank (15), the tank (15) having a casing (20) extending upwards from a bottom (21) to a top wall (22). The storage device (10) is provided with at least one inflatable bag (25) arranged inside said casing, said device including inflation/deflation means (35) for inflating each inflatable bag (25) at least in part so as to reach an inflated volume prior to filling the tank, and for deflating said inflatable bag after filling in order to guarantee the presence of an expansion volume inside said tank.

Claims

1. A storage device for storing fuel, the device having at least one tank, the tank having a casing extending upwards from a bottom to a top wall, wherein the storage device is provided with at least one inflatable bag arranged inside the casing, the storage device including inflation/deflation means inflating each inflatable bag at least in part so as to reach an inflated volume prior to filling the tank, and for deflating the inflatable bag after filling in order to guarantee an expansion volume inside the tank, wherein the at least one inflatable bag is fastened to the bottom of the casing in order to provide the expansion volume and also to provide at least one slope having a variable angle of inclination to direct the fuel towards a predetermined zone of the tank by gravity, wherein the at least one inflatable bag is compartmentalized so as to present a first compartment for inflating/deflating the expansion volume, and a second compartment in order to provide the at least one slope.

2. A device according to claim 1, wherein the storage device includes measurement means for measuring a volume of fuel and connected to the inflation/deflation means in order to adjust the angle of inclination of the at least one slope automatically as a function of the volume of fuel.

3. A device according to claim 1, wherein the storage device includes a measurement system for measuring flight duration, and wherein the storage device includes a pressure sensor.

4. A device according to claim 1, wherein the storage device includes manual control means for the inflation/deflation means, and wherein the storage device is provided with display means for displaying information relating to the slope.

5. A device according to claim 1, wherein the storage device is provided with a gauging system for measuring a depth of fuel in the tank, and the gauging system includes a gauging relationship for each authorized angle of inclination of the slope, each gauging relationship providing a volume of fuel as a function of the depth.

6. An aircraft, including a storage device according to claim 1.

7. A method of storing fuel in a storage device, the storage device having at least one tank, the tank having a casing extending upwards from a bottom to a top wall, wherein the storage device is provided with at least one inflatable bag arranged inside the casing, the storage device including inflation/deflation means inflating each inflatable bag at least in part so as to reach an inflated volume prior to filling the tank, and for deflating the inflatable bag after filling in order to guarantee an expansion volume inside the tank, the method comprising inflating the at least one inflatable bag to a predetermined volume in order to provide an expansion volume in the tank prior to filling the tank with fuel, filling the tank with fuel while the at least one inflatable bag is at the predetermined volume, and then deflating the at least one inflatable bag after filling the tank with fuel.

8. A method according to claim 7, further comprising inflating the at least one inflatable bag when the volume of fuel in the tank is less than a predetermined threshold after filling the tank with fuel in order to provide a slope at the bottom of the tank enabling fuel contained in the tank to be directed by gravity towards a predetermined zone of the tank as a function of fuel level.

9. A method according to claim 7, wherein in order to provide a slope enabling fuel contained in the tank to be directed by gravity towards a predetermined zone, the following steps are performed: when fuel volume is greater than a predetermined threshold after filling the tank with fuel, inflating the at least one inflatable bag once the volume of the fuel drops below the predetermined threshold; and when fuel volume does not reach the predetermined threshold on filling the tank with fuel, inflating the inflatable bag at the end of filling.

10. A method according to claim 9, further comprising determining a gauging relationship to provide a volume of fuel as a function of a depth of fuel in the tank, and modifying the gauging relationship when the slope is modified.

11. A method according to claim 7, further comprising providing the storage device on an aircraft having at least one engine, and deflating the at least one inflatable bag when the engine is stopped.

12. A method according to claim 7, wherein the at least one inflatable bag is deflated at the end of filling the tank with fuel if the level of fuel exceeds a predetermined threshold level.

13. A method according to claim 7, wherein the at least one inflatable bag is deflated at the end of filling the tank with fuel, and the inflating and deflating of the inflatable bag taking place while the inflatable bag is on the ground.

14. A method according to claim 7, wherein the at least one inflatable bag is deflated immediately after filling the tank with fuel.

15. A method according to claim 7, wherein the inflatable bag is immersed in fuel when filling the tank with fuel.

16. A method of storing fuel in a storage device in an aircraft, the method comprising: providing an aircraft having a fuel tank and an inflatable bag disposed within, and connected to, the fuel tank, the inflatable bag communicating with an inflation source to be inflatable between an inflated state, wherein the inflatable bag is inflated to a predetermined volume, and a deflated state, wherein the inflatable bag is deflated; inflating the inflatable bag to the predetermined volume; filling the fuel tank with fuel while the inflatable bag is inflated to the predetermined volume; and after filling the fuel tank with fuel, deflating the inflatable bag from the predetermined volume to the deflated state to provide a free volume inside the fuel tank to provide an expansion volume for the fuel in the fuel tank.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The invention and its advantages appear in greater detail from the following description of embodiments given by way of illustration and with reference to the accompanying figures, in which:

(2) FIG. 1 is a view of an aircraft provided with a storage device in a first embodiment;

(3) FIGS. 2 to 5 are views explaining the method implemented in the first embodiment;

(4) FIG. 6 is a view of an aircraft having a storage device in a second embodiment;

(5) FIG. 7 is a fragmentary view of a storage device in the second embodiment; and

(6) FIGS. 8 to 17 are views explaining the method of the invention implemented in the second embodiment.

(7) Elements present in more than one of the figures are given the same references in each of them.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1 shows a vehicle 1 in a first embodiment of the invention. By way of example, the vehicle is an aircraft, such as an aircraft having a rotary wing.

(9) The aircraft 1 possesses a storage device 10. The storage device 10 may in particular be a system for storing fuel for feeding to a power plant 9.

(10) The other members of the aircraft are not shown in order to avoid overcrowding FIG. 1.

(11) Independently of the embodiment, the storage device is provided with at least one tank 15 arranged in a compartment 5 of the vehicle 1. The tank 15 has a casing 20 defining a storage space.

(12) The casing 20 thus extends in elevation from a bottom 21 to a top wall 22, which are spaced apart by side walls 23.

(13) Furthermore, the storage device 10 includes a fuel transfer pipe 6 opening out into a predetermined fuel transfer zone 100 of the tank 15. This pipe 6 may comprise either at least one fuel transfer pipe 7, or else as in the example shown at least one fuel transfer pipe 7 and a booster pump 8.

(14) The storage device may also comprise a vent system 300 and a filler system 200, such as a gravity filler system.

(15) The storage device then comprises a system for arranging an expansion volume in the tank 15. The storage device 10 is provided with at least one bag 25 arranged inside the casing 20.

(16) In addition, inflation/deflation means 35 are connected to each bag 25 in order to inflate each inflatable bag 25 using a predetermined method. The inflation/deflation means 35 may include a pressure generator 36 communicating with at least one inflatable bag 25 via a hose pipe and a valve 38. The inflation/deflation means 35 may be activated manually or automatically via a control unit that applies a procedure defined by the manufacturer.

(17) Any reversible system for inflating/deflating a bag may be used.

(18) In addition, the device is optionally fitted with warning means for indicating the state of each bag to crew.

(19) The inflation/deflation means 35 inflate each bag at least in part in order to reach an inflated volume prior to filling the tank, and deflates said inflatable bag after filling in order to guarantee that an expansion volume is present in said tank.

(20) In a first embodiment, each inflatable bag is fastened inside the tank to the top wall 32 of the casing, possibly by reversible means.

(21) With reference to FIG. 2, at least one inflatable bag is inflated at least in part before filling the tank.

(22) In the first embodiment, each inflatable bag is inflated completely by the inflation/deflation means 35.

(23) The fuel tank is filled while in this condition, as shown in FIG. 3.

(24) The level of fuel in the tank rises and may immerse the inflatable bag, as shown in FIG. 4.

(25) Thereafter, at the end of filling, each inflatable bag is deflated by the inflation/deflation means 35.

(26) With reference to FIG. 5, this results in a drop in the level of the fuel, thereby enabling an expansion volume 500 to be created within the tank.

(27) In the second embodiment of FIG. 6, the storage device comprises a system for providing both an expansion volume and also variable slopes at the bottom 21 of at least one tank, and in particular at the bottom of a tank including a predetermined fuel transfer zone 100.

(28) The storage device 10 then has at least one inflatable bag 25 capable of being inflated on request, in particular so as to provide a slope 30 at the bottom of a tank. This slope 30 thus enables fuel contained in the tank to be directed by gravity towards the predetermined zone 100.

(29) Thereafter, the storage device 10 is provided with inflation/deflation means 35 to inflate/deflate the inflatable bag 25 of at least one tank. By inflating or deflating an inflatable bag, the inflation/deflation means 35 enable the angle of inclination of the slope 30 as generated by the inflatable bag to be adjusted between a minimum position and a maximum position, and also to generate an expansion volume.

(30) With reference to FIG. 7, each inflatable bag may be placed inside the casing 20 of a tank.

(31) Each inflatable bag is optionally fastened to the casing by reversible fastener means 26. By way of example, such reversible fastener means comprise a self-gripping strip making use of one layer provided with hooks and of another layer provided with loops.

(32) For example, only the face 25 of an inflatable bag that is remote from the generated slope 30 is fastened to the casing of the tank. The inflatable bag may then be fastened on the bottom 21 of the casing.

(33) In another variant, each inflatable bag is fastened in irreversible manner to the casing.

(34) The inflation/deflation means 35 may also comprise at least one pressure generator 36.

(35) A pressure generator 36 then communicates with at least one inflatable bag 25 via at least one hose pipe and a valve 38.

(36) More precisely, a first pipe 37 connects a valve 38 to the pressure generator, and a second pipe 39 connects the valve to an inflatable bag.

(37) The valve may occupy three positions so as to be connected to a fluid discharge pipe 37 for deflating an inflatable bag. The fluid discharge pipe 37 may be directed towards a pressure generator.

(38) A single pressure generator may be used for inflating/deflating some of the inflatable bags, or indeed or all of the inflatable bags, for example.

(39) Any device for conveying fluid from a pressure generator to an inflatable bag may also be envisaged.

(40) Optionally, each inflatable bag may have two independent compartments. The inflation/deflation means are then connected to each compartment. By way of example, the inflation/deflation means co-operate with a first compartment for generating an expansion volume in the tank, and with the second compartment for arranging a slope in the tank.

(41) The inflation/deflation means 35 inflate or deflate the inflatable bags as a function of the stage of flight and as a function of the quantity of fuel present in the tank.

(42) The internal storage space INT is reduced by inflating the inflatable bag. The invention thus proposes inflating the inflatable bags in predetermined situations both for the purpose of creating an expansion volume and also for the purpose of arranging slopes that enable fuel to be directed towards a predetermined zone.

(43) Depending on the variant, the storage device is then provided with means for measuring the volume of fuel 40 contained in the tank, and/or a measurement system 45 for measuring flight duration, and/or manual control means 50 for controlling said inflation/deflation means 35.

(44) In a first variant, the measurement means 40 for measuring the volume of fuel are connected to the inflation/deflation means 35 in order to adjust the angle of inclination of the slopes in the tank automatically as a function of the volume of fuel present in the tank.

(45) The measurement means 40 may include a sensor 41 that changes state when the depth of fuel in the tank crosses a threshold. The sensor 41 may be connected to each valve 38 of inflation/deflation means 35, or indeed to processor means for analyzing the state of the sensor in order to control each valve 38, where appropriate.

(46) The measurement means 40 optionally include a gauge system 42.

(47) The gauge system 42 optionally comprises a fuel gauge 43 co-operating with a processor unit 44. By way of example, the fuel gauge 43 measures the depth of fuel in the tank.

(48) The processor unit 44 deduces the volume of fuel contained on the basis of at least one gauging relationship for converting fuel depth into fuel volume.

(49) The processor unit communicates with each of the valves 38 of inflation/deflation means 35, or indeed with processor means for analyzing the information coming from the processor unit in order to control each of the valves 38, where appropriate.

(50) In a second variant, the storage device is provided with a measurement system 45 for measuring flight duration.

(51) By calculation, the manufacturer can determine a flight duration for which it can be guaranteed that the inside space as reduced as a result of inflating the inflatable bags in flight is sufficient for containing the stored fuel.

(52) The measurement system 45 then co-operates with the inflation/deflation means 35, optionally via a processor system 46.

(53) In a third variant, the storage device includes manual control means 50 for controlling the inflation/deflation means 35, e.g. connected to each of the valves 38.

(54) The valve may be provided with a position indicator 38.

(55) These variants may optionally be combined.

(56) Furthermore, the storage device may include at least one pressure sensor 55 for estimating the pressure of the fluid contained in an inflatable bag.

(57) The pressure sensor may co-operate with a pipe 39 of the inflation/deflation means 35.

(58) The sensor serves to deliver information representative of the state of at least one inflatable bag, and under such circumstances it is representative of the angle of inclination of the slope generated by the inflatable bag.

(59) For example, a low pressure indicates that an inflatable bag is deflated, whereas a high pressure indicates that an inflatable bag is inflated.

(60) The pressure sensor may be associated with display means 60 displaying information relating to said slope and/or to warning means 65 for warning an individual that said bag is inflated, via a visible or audible alarm.

(61) The display means and the warning means may be arranged in the same piece of equipment.

(62) In addition, when the storage device 10 is provided with a gauging system 42 for measuring the depth of fuel in the tank 15, the gauging system 42 may include a gauging relationship for each angle of inclination that is authorized for the slopes in the tank.

(63) Thus, by way of example, the storage device may apply one gauging relationship when the inflatable bags are deflated, and another gauging relationship when the inflatable bags are inflated.

(64) FIGS. 8 to 17 explain the method implemented by this storage device.

(65) With reference to FIG. 8, while on the ground and prior to filling, the inflatable bags are inflated, at least in part. Information may be forwarded to the crew to indicate that the bags are inflated, at least in part.

(66) The tank may then be filled with fuel, with filling being represented by arrow F.

(67) At the end of filling, the level of fuel in the tank may reach a level P0. At this point, the bags 25 are deflated so as to lower the level of fuel to a level P1.

(68) The tank then presents an expansion volume corresponding at least to the volume of the bags prior to the beginning of filling.

(69) Two situations may then arise. The free surface of the fuel may then either reach a threshold Q set by the manufacturer, or it may remain below the threshold Q. The threshold is defined by the manufacturer to guarantee that an expansion volume is present when the bags are inflated.

(70) With reference to FIG. 9, when the free surface of the fuel reaches said threshold Q at the end of filling, the inflatable bags remain deflated.

(71) In contrast, and with reference to FIG. 10, the consumption of fuel by the engines of an aircraft, for example, leads to the level of fuel in the tank dropping, as represented by arrow F1.

(72) Thereafter, and with reference to FIG. 11, when the level of fuel drops below the threshold Q, inflation of the inflatable bags is triggered.

(73) FIG. 12 shows the inflation of the inflatable bags. Each inflatable bag then defines a slope 30 that slopes towards a predetermined zone 100. Each slope thus presents an angle of inclination relative to the bottom wall of the casing of the tank.

(74) Under such circumstances, the level of fuel in the tank increases as represented by arrows F2. This level may go back above the threshold Q. Nevertheless, it should be understood that the inflatable bags then remain inflated.

(75) The gauging relationship applied by a gauging system is then advantageously modified.

(76) FIG. 13 shows a tank with inflatable bags that are fully inflated.

(77) With reference to FIG. 16, the inflatable bags are deflated after a flight and on the ground, at the request of the crew, or indeed on stopping the engines, for example.

(78) FIG. 17 then shows the state of the inflatable bags as a result of being deflated.

(79) FIGS. 14 and 15 show the method in the event of a partial fill. FIGS. 14 and 15 may also apply to an intermediate stage of flight.

(80) Consequently, when the fuel level does not reach the threshold Q at the end of filling, the inflatable bags are inflated at the end of filling. In other words, there is then no need to deflate the bags at the end of filling. If the bags have been inflated in part only, the bags may then be inflated completely. Deflation of the bags may also be inhibited in this configuration, e.g. by computer type inhibit means.

(81) Depending on the variant, it can be understood that the threshold Q may for example represent a depth of fuel in the tank, or a volume of fuel, or indeed a duration of flight.

(82) Naturally, the present invention may be subjected to numerous variations as to its implementation. Although several embodiments are described, it will readily be understood that it is not conceivable to identify exhaustively all possible embodiments. It is naturally possible to envisage replacing any of the means described by equivalent means without going beyond the ambit of the present invention.

(83) By way of example, the first embodiment and the second embodiment may be combined.