Safety device for a hazardous fluid transport circuit, aircraft and associated process

Abstract

A securing device (3) for a portion (100P) of a transport circuit (100) in which a fluid at risk flows from upstream to downstream for an aircraft, the securing device (3) comprising a conditioning bag (4) which is flexible and configured to be mounted around the portion (100P) of the transport circuit (100), the conditioning bag (4) defining a sealed enclosure when in use, the conditioning bag (4) comprising a first sealing element (40A), a second sealing element (40B), an access opening (41) configured to allow access to the portion (100P) of the transport circuit (100), the access opening (41) being resealable in a hermetic manner, the securing device (3) comprising a discharge valve (5) connected to the conditioning bag (4) and configured to discharge a fluid outside the conditioning bag (4). Figure from the summary: Figure 2

Description

Title of the invention: Device for securing a circuit for transporting a fluid at risk, aircraft and associated method Technical field

[0001] The present invention relates to the field of securing an installation in which hazardous fluids circulate, for example a flammable or detonating fluid when they are present in the air above a predetermined concentration, for example dihydrogen or methane. The invention finds a particularly interesting application for securing an aircraft fuel transport circuit.

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various States. In particular, an ambitious standard applies both to new types of aircraft and those in circulation requiring the implementation of technological solutions in order to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0003] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work covers new generations of aircraft engines, the lightening of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as essential complements to technological progress, aeronautical biofuels.

[0006] It has been proposed to power an aircraft turbine engine with a fuel, for example, dihydrogen or methane. The fuel is stored in a tank cryogenic and is conveyed to the turbine engine by a fuel circuit. For example, dihydrogen, like hydrogen, is a flammable gas if its volume concentration in air is between 4% and 75%. If its volume concentration in air is between 30% and 35%, the gas becomes detonating.

[0007] In order to secure the use of hydrogen for an aeronautical application, it is necessary to control the generation of hydrogen leaks in the air, as well as its possible effects. To this end, several systems for securing hydrogen leaks are known in the prior art, in particular, in fixed infrastructures used in industry.

[0008] It is known to use a helium sweep safety system which makes it possible to inert any hydrogen leak. The use of helium is known in the space sector but is not suitable for use in the aeronautical sector on a large scale due to its rarity and cost.

[0009] It is known to use a security system by packaging in sealed boxes in which the transport circuit extends. Such a solution is not applicable in the aeronautical field, due to: • the heavy congestion, in particular, near the turbine engines, • a significant supply of air into the environment of the turboshaft engine to ensure its cooling, • access requirements for turbine engine maintenance.

[0010] The installation of boxes is thus impractical. The invention thus aims to eliminate at least some of these drawbacks by proposing a system for securing a circuit for transporting a fluid at risk which can be installed in a constrained environment, that is to say, having a large footprint, a significant air supply and which must be accessible for maintenance. PRESENTATION OF THE INVENTION

[0011] The invention relates to a device for securing a portion of a transport circuit in which a fluid at risk circulates from upstream to downstream for an aircraft, the securing device comprising: • A packaging pouch that is flexible and configured to be mounted around the portion of the transport circuit, the packaging pouch defining a sealed enclosure when in use, the packaging pouch comprising: • a first sealing member configured to be mounted at an upstream end of the portion of the transport circuit • a second sealing member configured to be mounted at a downstream end of the portion of the transport circuit, • an access opening configured to allow access to the portion of the transport circuit, the access opening being closable in a sealed manner, • a discharge valve connected to the packaging bag and configured to discharge a fluid outside the packaging bag.

[0012] A sealed packaging bag advantageously allows for a reduced size when it is placed under vacuum. The packaging bag is deformable, in particular, to match the shape of the portion of the fuel circuit. This makes it possible to secure a portion of the transport circuit in a constrained environment, in particular, near a propulsion turbine engine of an aircraft. In the nominal configuration, the packaging bag is configured to be placed under vacuum, which limits its size and thus allows free circulation of air, which is advantageous for a propulsion turbine engine which must be cooled with an air flow.

[0013] According to one aspect, the discharge valve comprises a check valve configured to prevent any introduction of fluid into the packaging bag. This makes it possible to prevent any introduction of air into the packaging bag, which would increase the explosive risk.

[0014] In one aspect, the check valve is configured to automatically open if the internal pressure is greater than a safety pressure. This allows excess gaseous fuel to be automatically drained in the event of a leak.

[0015] According to one aspect, the safety device comprises a pressure sensor configured to measure an internal pressure in the packaging bag. Such a pressure sensor makes it possible to monitor the vacuum in the packaging bag but also any fluid leakage.

[0016] According to one aspect, the safety device comprises a rupture member configured to rupture if the internal pressure in the packaging bag exceeds a predetermined rupture pressure. Such a rupture member makes it possible to control an overpressure before a rupture of the packaging bag.

[0017] According to one aspect, the access opening comprises a sealed closure system. This allows access to the portion of the transport circuit to carry out maintenance operations.

[0018] According to one aspect, the securing device comprises a service member which is rigid and mounted to the packaging bag, the discharge valve being connected to the service member.

[0019] According to one aspect, the service member belongs to a nacelle of an aircraft.

[0020] An aircraft comprising at least one propulsion turbine engine is also presented. powered by a fuel circuit in which fuel circulates from upstream to downstream, the aircraft comprising a securing device, as presented previously, mounted around a portion of the fuel circuit.

[0021] According to one aspect, the aircraft comprising a nacelle in which the propulsion turbo-engine is mounted, the safety device is mounted in the nacelle.

[0022] Also presented is a method of mounting a securing device, as presented previously, for securing a portion of the transport circuit of a fluid at risk, the portion being fluidically disconnected from the transport circuit, the method comprising steps consisting of: • Position the portion of the transport circuit in the packaging pocket via the access opening, • Mount the first sealing member at an upstream end of the portion of the transport circuit, • Mount the second sealing member at a downstream end of the portion of the transport circuit and • Fluidly connect the portion to the transport circuit.

[0023] A method of using a securing device, as presented previously, is also presented to secure a portion of the transport circuit of a fluid at risk, the packaging bag being sealed, the method comprising steps consisting of: • Create a vacuum in the packaging bag via the discharge valve, then • Measure an internal pressure in the packaging bag and • Issue an alarm if the internal pressure in the packaging bag is greater than a predetermined leakage pressure. PRESENTATION OF FIGURES

[0024] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0025] [Fig.l] is a schematic representation of an aircraft comprising a fuel circuit supplying propulsion turbine engines.

[0026] [Fig.2] is a schematic representation of a safety device mounted on a portion of a fuel circuit in a nacelle.

[0027] [Fig. 3] is a schematic representation of an example of mounting the safety device on a portion of a fuel circuit.

[0028] [Fig.4] is a schematic representation of the securing device in mounted position before putting into service.

[0029] [Fig.5] is a schematic representation of the safety device in the mounted position when it is put into service.

[0030] [Fig.6] is a schematic representation of the safety device when a leak occurs.

[0031] [Fig.7] is a schematic representation of the safety device during emptying.

[0032] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0033] With reference to [Fig. 1], there is shown an aircraft A comprising a plurality of propulsion turbine engines T which are powered by a fuel circuit 100 connected to a fuel tank R. The invention applies to the aeronautical field but also to space.

[0034] In this example, the fuel is dihydrogen but it goes without saying that the invention applies to any type of high-risk fuel, in particular methane. Generally speaking, the invention applies to any circuit for transporting a high-risk fluid both on board and on the ground.

[0035] With reference to [Fig. 2], a fuel circuit 100 is schematically represented which is configured to convey fuel from upstream to downstream to a propulsion turbine engine T. In this example, the fuel circuit 100 comprises a portion 100P capable of generating fuel leaks which must be contained to ensure the safety of the aircraft A. In this example, the portion 100P comprises several pieces of equipment such as a drive pump 101, a control valve 102, etc. It goes without saying that the portion 100P could comprise a variety of pieces of equipment.

[0036] In this example, with reference to figures 1 and 2, the aircraft A comprises a nacelle 2 in which the propulsion turbine engine T is mounted. The portion 100P to be secured extends into the nacelle 2, in particular, into an enclosure comprising a fire barrier 20 as illustrated in [Fig.2].

[0037] The environment of a nacelle 2 is very constrained in terms of size due to the presence of the propulsion turbine engine T, the need for air ventilation of said propulsion turbine engine T. In addition, the propulsion turbine engine T must be accessible in the event of maintenance. The propulsion turbine engine T is itself equipped with numerous hydraulic, pneumatic, electrical or control systems.

[0038] With reference to [Fig.2], the portion 100P of the fuel circuit 100 is secured by a securing device 3 which will now be presented in detail.

[0039] As illustrated in [Fig.2], a safety device 3 is schematically represented for securing the portion 100P of the fuel circuit 100 in which fuel circulates from upstream to downstream.

[0040] The securing device 3 comprises a packaging bag 4 which is flexible and configured to be mounted around the portion 100P of the fuel circuit 100, the packaging bag 4 defining a sealed enclosure during its use. Preferably, the packaging bag 4 is made of a polymer-type material (single layer, multilayer, composite or other), for example, TFE (or Teflon®), natural or synthetic rubber, silicone, etc. In order to increase its mechanical strength, the packaging bag 4 may comprise a reinforcement (a composite mesh, a belt or other), for example, with polyester, nylon, aramid or steel. The packaging bag 4 is deformable, in particular, to match the shape of the portion 100P of the fuel circuit 100.

[0041] The dimensions of the packaging pocket 4 are determined to correspond to the portion 100P to be secured.

[0042] In this example, with reference to [Fig.2], the packaging bag 4 comprises a first sealing member 40A mounted at an upstream end 100A of the portion 100P of the transport circuit 100 and a second sealing member 40B mounted at a downstream end 100B of the portion 100P of the transport circuit 100. It goes without saying that if the portion 100P has a complex shape with several upstream / downstream ends, the packaging bag 4 comprises as many sealing members 40A, 40B.

[0043] By way of example, each sealing member 40A, 40B is in the form of an elastic ring inside which one end 100A, 100B of the portion 100P of the fuel circuit 100 can extend. It goes without saying that a sealing member 40A, 40B could be in a different form, for example, in the form of a clamp, in particular, forming an integral part of a flange between two components of the fuel circuit 100.

[0044] With reference to [Fig. 2], the packaging bag 4 comprises an access opening 41 configured to allow access to the portion 100P of the fuel circuit 100. The access opening 41 is resealable in a sealed manner. Preferably, the access opening 41 comprises a sealed closure system 42 which may take various forms, for example, a zipper closure, a roll closure with, in certain cases, a clamping or position-holding member via a clamp system.

[0045] The access opening 41 is preferably sized to allow the removal of equipment from the portion 100P or the complete removal of the portion 100P.

[0046] In the closed position, the packaging bag 4 is configured to withstand a maximum pressure Pmax which is between 0.11 MPa and 0.5 MPa. Preferably, the packaging bag 4 is configured to withstand a temperature above 200°C.

[0047] With reference to [Fig. 2], the securing device 3 comprises a service member 8 which is rigid and mounted on the packaging pocket 4. The service member 8 belongs in this example to the nacelle 2 of an aircraft A so as to be accessible by an operator from outside the nacelle 2 in order to carry out maintenance. The service member 8 is in this example in the form of a rigid plate but it goes without saying that it could be in another form.

[0048] As illustrated in [Fig.2], the safety device 3 comprises a discharge valve 5 connected to the packaging bag 4 and configured to discharge a fluid outside the packaging bag 4. In this example, the discharge valve 5 comprises a non-return valve 50 configured to prevent any introduction of fluid inside the packaging bag 4. In other words, the discharge valve 5 allows unidirectional circulation of fluid towards the outside of the packaging bag 4. The discharge valve 5 is connected to the service member 8 to be easily accessible by an operator as will be presented later.

[0049] Preferably, the non-return valve 50 is configured to open automatically if the internal pressure P4 is greater than a safety pressure PS which corresponds, for example, to the atmospheric pressure on the ground. This makes it possible to automatically drain excess gaseous fuel in the event of a leak. Preferably, the sealed closure system 42 has a pressure resistance greater than the setting of the non-return valve 50, i.e., the safety pressure PS.

[0050] The safety device 3 further comprises a pressure sensor 6 configured to measure the internal pressure P4 in the packaging bag 4. In this example, the pressure sensor 6 is mounted on the service member 8 to facilitate maintenance and access to the pressure measurements. Preferably, the pressure sensor 6 is connected to a computer so as to read the internal pressure P4 as will be presented later. According to a preferred aspect, the pressure sensor 6 is used to carry out a relative pressure measurement, in particular by coupling to a pressure sensor located outside the packaging bag 4, to adjust the alarm thresholds as a function of the flight altitude and / or the speed of the propulsion turbine engine T.

[0051] The securing device 3 further comprises a rupture member 7 configured to rupture if the internal pressure P4 in the packaging bag 4 exceeds a predetermined rupture pressure PR. Preferably, the predetermined rupture pressure PR is lower than the maximum pressure threshold Pmax of the packaging bag. packaging 4 so as to promote a controlled rupture of the rupture member 7 before uncontrolled damage to the packaging bag 4. Thus, the rupture member 7 is in the form of a safety device in the event of removal as will be presented later. In this example, the rupture member 7 is mounted on the service member 8 to facilitate maintenance. The rupture member 7 is preferably in the form of a rupture disc known to those skilled in the art under the English designation “Burst disc”. The rupture member 7 can also be reversible and be in the form of a valve having a setting greater than the non-return valve 50.

[0052] According to one aspect, the safety device 3 could also comprise a fuel sensor, in particular a hydrogen sensor, to detect any leak as will be presented later.

[0053] With reference to [Fig. 3], there is shown schematically an assembly of the securing device 3 for securing the portion 100P of the fuel circuit 100. Initially, the portion 100P is fluidically disconnected from the fuel circuit 100.

[0054] The assembly method comprises steps consisting of: • Position the portion 100P of the fuel circuit 100 in the packaging pocket 4 via the access opening 41, • Mount the first sealing member 40A at an upstream end 100A of the portion 100P of the fuel circuit 100, • Mount the second sealing member 40B at a downstream end 100B of the portion 100P of the fuel circuit 100 and • Fluidly connect the portion 100P of the fuel circuit 100 by connecting the ends 100A, 100B to the fuel circuit 100.

[0055] The packaging bag 4 can then be closed so that it is watertight. It goes without saying that the assembly could be carried out differently, in particular, by keeping the portion 100P fluidly connected to the fuel circuit 100 when installing the packaging bag 4.

[0056] With reference to figures 4 and 5, a commissioning of the safety device 3 is shown schematically. The packaging bag 4 is sealed on the portion 100P of the fuel circuit 100 as illustrated in [Fig.4],

[0057] The commissioning method comprises a step of creating a vacuum in the packaging bag 4 via the discharge valve 5 as illustrated in [Fig. 5]. In this example, a vacuum pump 51 is mounted on the discharge valve 5 to suck air into the packaging bag 4. The non-return valve 50 advantageously allows such suction of the air contained in the packaging bag. 4. Preferably, the method comprises a step of measuring the internal pressure P4 in the packaging bag 4 in order to ensure a sufficient vacuum in the packaging bag 4. Preferably, in nominal conditions following commissioning, the internal pressure P4 is less than 0.1 Pa, preferably less than 0.0001 Pa. The lower the internal pressure P4, the more the explosive risk is reduced.

[0058] The conditioning pocket 4 thus occupies a restricted volume and can adapt to the size of the other equipment present in the nacelle 2. The conditioning pocket 4 thus does not hinder the circulation of air necessary for cooling the propulsion turbine engine T. Furthermore, advantageously, the vacuum created in the conditioning pocket 4 makes it possible to reinforce the thermal insulation of the portion 100P of the fuel circuit 100, which guarantees that the propulsion turbine engine T is supplied with fuel having an optimal pressure and temperature.

[0059] With reference to figures 6 and 7, there is shown schematically a securing of the portion 100P of the fuel circuit 100 following the appearance of a leak F. For example, with reference to [Fig.6], a leak F is detected at the level of the drive pump 101 and gaseous fuel begins to fill the conditioning bag 4, which increases the internal pressure P4.

[0060] The safety method comprises a step consisting of measuring the internal pressure P4 in the packaging bag 4 and issuing an alarm if the internal pressure P4 in the packaging bag 4 is greater than a predetermined leak pressure PF. Preferably, the leak pressure PF is lower than the safety pressure PS and the burst pressure PR. Preferably, the leak pressure PF is adapted according to the flight altitude and / or the speed of the propulsion turbine engine T.

[0061] The internal pressure P4 is measured by the pressure sensor 6 and can be used by a computer to issue an alarm, in particular, an alarm for the pilot. Preferably, countermeasures are implemented following the issue of the alarm, for example, stopping the circulation of fuel in the portion 100P of the fuel circuit 100.

[0062] If the pressure rise is too rapid, for example due to a significant leak, the non-return valve 50 opens at the safety pressure PS and directs the fuel out of the conditioning bag 4, for example, to a recovery tank or into the ambient environment. In the event of a malfunction, the rupture member 7 advantageously fulfills its function if the internal pressure P4 reaches the rupture pressure PR.

[0063] Advantageously, with reference to [Fig.7], the fuel present in the conditioning bag 4 can be drained via the discharge valve 5 by means of a suction pump 52, in particular, compatible with an explosive atmosphere. According to one aspect, the same suction pump can be used for commissioning and for draining. According to one aspect, when draining the fuel, an inert gas GI (nitrogen or other) can be mixed with the fuel to lower the fuel concentration during its draining and thus reduce the explosive risk. Once the fuel has been drained, the conditioning bag 4 can be opened to treat the origin of the leak and allow a return to service. Since the service plate 8 is positioned on the nacelle 2 and is accessible from outside the nacelle 2, the return to service is convenient.

[0064] Thanks to the invention, the portion 100P of the fuel circuit 100 can be secured in a practical manner in a constrained environment having a large footprint and not having to be obstructed to allow circulation of air intended for the propulsion turbine engine T.

Claims

Claims

1. Device (3) for securing a portion (100P) of a transport circuit (100) in which a fluid at risk circulates from upstream to downstream for an aircraft (A), the securing device (3) comprising: • A packaging bag (4) which is flexible and configured to be mounted around the portion (100P) of the transport circuit (100), the packaging bag (4) defining a sealed enclosure during its use, the packaging bag (4) comprising: • a first sealing member (40A) configured to be mounted at an upstream end (100A) of the portion (100P) of the transport circuit (100) • a second sealing member (40B) configured to be mounted at a downstream end (100B) of the portion (100P) of the transport circuit (100), • an access opening (41) configured to allow access to the portion (100P) of the transport circuit (100), the access opening (41) being tightly closable,• a discharge valve (5) connected to the packaging bag (4) and configured to discharge a fluid outside the packaging bag (4).,

2. Securing device (3) according to claim 1, in which the discharge valve (5) comprises a non-return valve (50) configured to prevent any introduction of fluid inside the packaging bag (4).

3. Securing device (3) according to one of claims 1 to 2, comprising a pressure sensor (6) configured to measure an internal pressure (P4) in the packaging pocket (4).

4. Securing device (3) according to one of claims 1 to 3, comprising a rupture member (7) configured to rupture if the internal pressure (P4) in the packaging bag (4) exceeds a predetermined rupture pressure (PR).

5. Securing device (3) according to one of claims 1 to 4, comprising a service member (8) which is rigid and mounted on the pocket conditioning (4), the discharge valve (5) being connected to the service member (8).

6. Securing device (3) according to claim 5, in which the service member (8) belongs to a nacelle (2) of an aircraft (A).

7. Aircraft (A) comprising at least one propulsion turbine engine (T) powered by a fuel circuit (100) in which fuel circulates from upstream to downstream, the aircraft (A) comprising a safety device (3) according to one of claims 1 to 6 mounted around a portion (100P) of the fuel circuit (100).

8. Aircraft (A) according to claim 7, comprising a nacelle (2) in which the propulsion turbine engine (T) is mounted, the safety device (3) is mounted in the nacelle (2).

9. Method for mounting a securing device (3) according to one of claims 1 to 6 for securing a portion (100P) of the transport circuit (100) of a fluid at risk, the portion (100P) being fluidically disconnected from the transport circuit (100), the method comprising steps consisting of: • Positioning the portion (100P) of the transport circuit (100) in the packaging bag (4) via the access opening (41), • Mounting the first sealing member (40A) at an upstream end (100A) of the portion (100P) of the transport circuit (100), • Mounting the second sealing member (40B) at a downstream end (100B) of the portion (100P) of the transport circuit (100) and • Fluidly connecting the portion (100P) to the transport circuit (100).

10. Method for using a securing device (3) according to one of claims 1 to 6 to secure a portion (100P) of the transport circuit (100) of a fluid at risk, the packaging bag (4) being sealed, the method comprising steps consisting of: • Creating a vacuum in the packaging bag (4) via the discharge valve (5), then • Measuring an internal pressure (P4) in the packaging bag (4) and Issue an alarm if the internal pressure (P4) in the packaging bag (4) is higher than a predetermined leak pressure (PF).

Images