Aircraft comprising a propulsion assembly and a fire extinguishing system for the propulsion assembly

Abstract

The invention relates to an aircraft comprising a propulsion assembly and a fire extinguishing system thereof, the fire extinguishing system comprising two fire extinguishing agent tanks, a control element associated with each tank and a detection element, the control element being actuated by the pilot to open the tanks, the detection element detecting a fire and, if appropriate, issuing a fire warning signal, the propulsion assembly comprising a first compartment and a second compartment, each compartment comprising at least one fire zone, the fire extinguishing system comprising a bypass valve controlled by a positioning unit, a set of pipes connecting each tank to each fire zone via the bypass valve, the positioning unit detecting a fire in a fire zone in the first compartment and, if appropriate, controlling the bypass valve so that the bypass valve adopts a first state, otherwise adopting a second state, in which in the first state, after activation of the control element, the fire extinguishing agent in the tank is discharged towards the fire zone in the first compartment, and in the second state, after activation of the control element, the fire extinguishing agent in the tank is discharged towards the fire zone in the second compartment.

Description

Technical Field

[0001] The invention relates to an aircraft comprising a propulsion assembly and a fire extinguishing system dedicated to said propulsion assembly for detecting a possible fire in the propulsion assembly and extinguishing the fire. Background Art

[0002] In a known manner, an aircraft has at least one propulsion assembly fastened under each of its wings and a fire extinguishing system dedicated to each propulsion assembly, which makes it possible to detect the occurrence of a fire in the propulsion assembly and to extinguish it.

[0003] Figure 1 is a schematic representation of a prior art fire extinguishing system 1 dedicated to a propulsion assembly 2. The propulsion assembly 2 comprises a plurality of fire zones Z1, Z2 of different sizes, which are closed by walls and fireproof seals in order to prevent the fire from spreading outside the fire zones and thus also from spreading from one fire zone to the other.

[0004] In each fire zone Z1, Z2, the fire extinguishing system 1 comprises at least one detection circuit 3 equipped with at least one fire sensor for detecting a fire. All detection circuits 3 are electrically connected to a detection unit 4 configured to trigger an audible or visual fire alarm in the cockpit intended for the pilots if a fire is detected by the fire sensor of the fire zone Z1, Z2.

[0005] After the fire alarm has been triggered, the pilot follows a procedure that causes him or her to actuate a first control C1 located in the cockpit to trigger the discharge of a volume of extinguishing agent contained in a first reservoir R1 towards each fire zone Z1, Z2. If the fire persists, the pilot actuates a second control C2 located in the cockpit to repeat the same actions, but this time using the second reservoir R2.

[0006] According to the design, since the detection unit 4 cannot detect exactly which fire zone Z1 , Z2 is on fire, each reservoir R1 , R2 contains a certain volume of extinguishing agent necessary to supply all fire zones Z1 , Z2 with enough extinguishing agent to extinguish the fires therein.

[0007] Such fire extinguishing systems are completely satisfactory; however, the demands that prevail in aircraft construction for reducing mass and / or volume have led to the need to find fire extinguishing systems that provide the same efficiency with reduced mass and / or volume. Summary of the Invention

[0008] The present invention is intended to meet all or part of this need and relates to an aircraft comprising a cockpit, at least one propulsion assembly and a fire extinguishing system dedicated to each propulsion assembly, each fire extinguishing system comprising two reservoirs containing a fire extinguishing agent, a control associated with each reservoir, and a detection assembly configured to detect a fire in the propulsion assembly to which the fire extinguishing system is dedicated and, if appropriate, emit a fire warning signal intended for a visual or acoustic transducer located in the cockpit, characterized in that the propulsion assembly comprises a first compartment and a second compartment, each compartment comprising at least one fire zone, and characterized in that The fire extinguishing system comprises a bypass valve controlled by a positioning unit, a set of pipes connecting each reservoir to each of the fire zones via the bypass valve, the positioning unit being configured to detect a fire in the one or more fire zones in the first compartment and, if appropriate, to control the bypass valve so that the bypass valve adopts a first state, referred to as a controlled state, otherwise the bypass valve is controlled to adopt a second state, referred to as a default state, in which, after activating the control associated with the reservoir, the fire extinguishing agent in the reservoir is discharged toward the one or more fire zones in the first compartment, and in which, after activating the control associated with the reservoir, the fire extinguishing agent in the reservoir is discharged toward the fire zones in the second compartment.

[0009] According to the present invention, in the event of a fire, the fire extinguishing system is able to determine whether the first compartment is on fire and, if so, to direct the spread of the fire extinguishing agent only towards one or more fire zones in the first compartment, or otherwise towards one or more fire zones in the second compartment. Thus, the volume of fire extinguishing agent in each reservoir can be reduced compared to the prior art, since it is no longer necessary to contain a volume sufficient to extinguish fires in all the fire zones of the propulsion assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above-mentioned and other features of the present invention will appear more clearly after reading the following description of exemplary embodiments, which description is given with reference to the accompanying drawings, in which:

[0011] [ Figure 1 ] Figure 1 is a schematic representation of a prior art fire suppression system, which has been described;

[0012] [ Figure 2 ] Figure 2 is a schematic representation of an aircraft according to the invention comprising a propulsion assembly and a fire extinguishing system dedicated to said propulsion assembly;

[0013] [ Figure 3 ] Figure 3 and Figure 1 Similar, yes Figure 2 Schematic representation of the fire extinguishing system of the aircraft shown in FIG. DETAILED DESCRIPTION

[0014] refer to Figure 2 and Figure 3 , an aircraft A has at least one propulsion assembly 10 attached below each of its wings W. Each propulsion assembly 10 has a nacelle 11 enclosing an engine (not shown), and an engine fastening pylon 12 fastened below the aircraft wing W, and the engine is attached below the engine fastening pylon.

[0015] The propulsion assembly 10 is divided into a first compartment K1 and a second compartment K2. Each compartment K1, K2 includes at least one fire zone Z1, Z2. The fire zones Z1, Z2 of the propulsion assembly 10 are separated from each other by walls and fire seals (not shown) to contain any fire within the boundaries of one fire zone and prevent the fire from spreading to another fire zone.

[0016] It should be noted that in Figure 3 In the example shown in FIG, two fire zones Z1, Z2 are shown, wherein one fire zone Z1 belongs to the first compartment K1 and one fire zone Z2 belongs to the second compartment K2. In the remainder of the description, unless otherwise stated, this embodiment will be described in which each compartment K1, K2 comprises a single fire zone Z1, Z2.

[0017] The aircraft A comprises a fire extinguishing system 20 dedicated to each propulsion assembly 10 , which serves to detect any fire that may occur and to extinguish it by delivering an extinguishing agent.

[0018] Conventionally, the fire extinguishing system 20 of the propulsion assembly 10 comprises two reservoirs R1, R2 (for example of the same capacity), each containing a certain volume of extinguishing agent, a set of pipes (lines shown in the figure) connecting the reservoirs R1, R2 to all the fire zones Z1, Z2, a detection assembly 21 for detecting a fire and, if appropriate, triggering a fire warning in the cockpit of the aircraft A, and two activation controls C1, C2 located in the cockpit, which can be actuated by the pilot to trigger the discharge of extinguishing agent towards the fire to be extinguished, in particular when a fire warning is issued and the pilot hears it.

[0019] Each reservoir R1 , R2 , located for example in the pylon 12 of the propulsion assembly 10 or in the fuselage 13 , is equipped with an opening and a triggering system.

[0020] For example, the opening and triggering system includes a discharge head Rd1, Rd2 screwed onto the reservoir and a pyrotechnic cartridge (not shown) disposed within the discharge head Rd1, Rd2, opposite a seal (not shown) adjacent to the reservoir. The pyrotechnic cartridge of the first reservoir R1 is ignited by actuating a first activation control C1, thereby breaking the seal and releasing pressurized fire extinguishing agent from the first reservoir R1. Similarly, the pyrotechnic cartridge of the second reservoir R2 is ignited by actuating a second activation control C2, thereby breaking the seal and releasing pressurized fire extinguishing agent from the second reservoir R2. For example, the first control C1 and the second control C2 are buttons or levers.

[0021] The detection assembly 21 includes, for example, a detection unit 22 located in the fuselage 13, and a plurality of detection circuits L ( Figure 3 Only one detection circuit is shown in FIG. 1 ). Each detection circuit L comprises at least a portion dedicated to a fire zone Z1, Z2 of the propulsion assembly 10, i.e. for each fire zone Z1, Z2 in each compartment K1, K2, there is at least a portion of the detection circuit L. A portion of the detection circuit L comprises, for the fire zone Z1, Z2 to which it is dedicated, at least one fire sensor 23, 24 arranged in said fire zone Z1, Z2. Figure 3 In FIG. 1 , the single detection circuit L shown comprises a portion with a fire sensor 23 dedicated to the fire zone Z2 in the second compartment K2 and a portion with a fire sensor 24 dedicated to the fire zone Z1 in the first compartment K1 .

[0022] The detection unit 22 continuously measures the electrical value of the circuit formed by each detection loop L and issues a fire warning signal S_Fire when the measurement result of the electrical value indicates a fire. The fire warning signal S_Fire is received by at least one visual and / or acoustic transducer 25 located in the cockpit to trigger a fire warning intended for the pilots and warn them of the fire in the propulsion assembly 10.

[0023] In the case where the measured electrical value is resistance (in this case, equivalent impedance measurement), the detection unit 22 issues a fire warning signal S_Fire when the resistance value measured on at least one detection circuit L falls within a predetermined range.

[0024] According to the present invention, the fire extinguishing system 20 is capable of determining, in the event of a fire, whether the fire zone Z1, Z2 in the compartments K1, K2 is on fire and is capable of directing the diffusion of the fire extinguishing agent only toward the compartments K1, K2 including the fire zone Z1, Z2 on fire, or otherwise toward another compartment K1, K2.

[0025] To this end, the fire extinguishing system 20 according to the invention comprises:

[0026] - a bypass valve 26 having an inlet 26a and two outlets 26b, 26c. The inlet 26a of the bypass valve 26 is connected via a pipe to each reservoir R1, R2, whereas the first outlet 26b opens via a pipe into the fire zone Z1 in the first compartment K1 and the second outlet 26c opens via a pipe into the fire zone Z2 in the second compartment K2.

[0027] A positioning unit 27 to which both the detection circuit or circuits L dedicated to the fire zone Z1 in the first compartment K1 and the bypass valve 26 are electrically connected.

[0028] The bypass valve 26 is configured to be commanded to adopt two states, namely a first state, referred to as the controlled state, in which a fluid path extends through the valve from the inlet 26a to the first outlet 26b leading to the first compartment K1, and a second state, referred to as the default state, in which a fluid path extends through the valve from the inlet 26a to the second outlet 26c leading to the second compartment K2.

[0029] In one embodiment, the bypass valve 26 is, for example, of an electromechanical type and comprises a body (not shown) having an inlet to which the discharge head of each of the two reservoirs R1 and R2 is fluidically connected, for example, by a Y-connector, and two fluid outlets 26b-c, one of which opens via a pipe into the fire zone Z1 in the first compartment K1, and the other of which opens via another pipe into the fire zone Z2 in the second compartment K2. The bypass valve 26 comprises an actuator (not shown) electrically connected to a positioning unit 27, which allows for movement of a movable gate (not shown) in the body of the bypass valve 26. The movable gate can be positioned in one of two positions to direct the extinguishing agent entering the body of the bypass valve 26 via the fluid inlet 26a: a first position corresponding to the controlled state of the bypass valve 26, and a second position corresponding to the default state of the bypass valve 26.

[0030] The locating unit 27 is configured to measure the electrical value of the circuit formed by one or more parts of the detection circuit L dedicated to the first compartment K1 and to send a control signal S_Com to the bypass valve 26 to command the valve to adopt its controlled state if the measured value indicates a fire; otherwise the bypass valve 26 remains in its default state.

[0031] For example, the measured electrical value is resistance (equivalent impedance measurement). In this case, the positioning unit 27 sends the control signal S_Com when the measured resistance value is within a predetermined value range.

[0032] If there is a fire in the fire zone Z1 in the first compartment K1, the detection logic implemented by the fire extinguishing system 20 is as follows:

[0033] 1) The positioning unit detects a fire in fire zone Z1 and sends a control signal S_Com to the bypass valve 26 to position the bypass valve in its controlled state. Simultaneously, the detection unit 22 detects a fire in the propulsion assembly 10 and issues a warning signal S_Fire. The warning signal S_Fire is converted by a suitable transducer 25 located in the cockpit into a visual and / or audible warning intended for the pilot.

[0034] 2) The pilot then activates the fire procedure and actuates the first control C1 : the extinguishing agent in the first reservoir R1 is released towards the first compartment K1 to extinguish the fire detected in the fire zone Z1 .

[0035] 3) In case the fire alarm in the cockpit is still active a few seconds after activation of the first control C1 , the pilot actuates the second control C2 and the extinguishing agent in the second reservoir R2 is released and discharged towards the first compartment K1 .

[0036] If there is a fire in the fire zone in the second compartment K2, the detection logic implemented by the fire extinguishing system 20 is as follows:

[0037] 1) The positioning unit 27 does not detect a fire in the first compartment K1; the bypass valve 26 remains in its default state. In contrast, the detection unit 22 detects a fire in the propulsion assembly 10 and issues a warning signal S_Fire. The warning signal S_Fire is converted by a suitable transducer 25 located in the cockpit into a visual and / or audible warning for the pilot.

[0038] 2) The pilot then initiates the fire procedure and actuates the first control C1 : the extinguishing agent in the first reservoir R1 is released towards the second compartment K2 .

[0039] 3) After a few seconds, while the fire alarm is still active, the pilot actuates the second control C2 and the extinguishing agent in the second reservoir R2 is released and discharged towards the second compartment K2.

[0040] Preferably, the logic is designed so that once the bypass valve 26 has been positioned in its controlled state and control C1 or control C2 has been actuated, only operator maintenance on the fire suppression system 20 can return the bypass valve 26 to its default state.

[0041] In the case where each compartment K1 , K2 of the propulsion assembly 10 contains a single fire zone Z1 , Z2, the amount of extinguishing agent contained in each reservoir R1 , R2 of the fire extinguishing system 20 according to the invention is limited to the amount necessary to extinguish the fire in the most important of the fire zones Z1 and Z2.

[0042] The design of the fire extinguishing system according to the invention therefore makes it possible to reduce the quantity of extinguishing agent contained in each reservoir R1 , R2 and therefore to reduce the mass on board the aircraft A, compared to the prior art.

[0043] In the case where the propulsion assembly 10 has more than two fire zones, for example if one or both compartments each include multiple fire zones, the fire detection system 20 is modified as follows for this case as described above: if the first compartment includes multiple fire zones, the first fluid outlet 26b of the bypass valve 26 is connected to each fire zone in the first compartment K1 via a pipe, and if the second compartment includes multiple fire zones, the second fluid outlet 26c of the bypass valve 26 is connected to each fire zone in the second compartment K2 via a pipe.

[0044] Furthermore, in this case, the locating unit 27 is also connected to the bypass valve 26, to one or more parts of the detection circuit L dedicated to the fire zone in the first compartment K1 (and therefore to the fire sensor of the detection circuit). The locating unit 27 measures the electrical value of the circuit formed by said one or more parts and sends a control signal S_Com to the bypass valve 26 in order to control said valve 26 so that if the signal has a value indicative of a fire in the first compartment K1, the valve adopts its controlled state.

[0045] In the latter case, the amount of extinguishing agent contained in each reservoir R1, R2 of the fire extinguishing system 20 according to the invention is limited by the amount necessary to extinguish the fire in the most important compartment, i.e. the compartment that, based on the fire simulation (e.g. taking into account the flammable liquid lines passing through the compartment, the larger volume or the greater ventilation), requires the most extinguishing agent to extinguish the fire therein. Here again, the design of the fire extinguishing system 20 according to the invention thus makes it possible to reduce the amount of extinguishing agent contained in each reservoir R1, R2 and therefore reduce the onboard mass compared to the prior art.

[0046] The choice between the first compartment K1 and the second compartment K2 for the controlled / default state of the bypass valve 26 can be arbitrary. In another example, taking into account the architecture of the propulsion assembly (type of flammable fluid, number of pipes conveying the flammable fluid, environmental conditions such as those close to the engine and its hot parts), the controlled state of the bypass valve is selected so that the extinguishing agent is delivered to the fire zone or zones with the highest probability of fire risk compared to the other compartment K2, K1.

Claims

1. An aircraft (A) comprising a cockpit, at least one propulsion assembly (10) and a fire extinguishing system (20) dedicated to each propulsion assembly, each fire extinguishing system (20) comprising two reservoirs (R1, R2), a control (C1, C2) associated with each reservoir (R1, R2), each reservoir containing a fire extinguishing agent, the control being actuatable by the pilot to open the reservoir in order to release the fire extinguishing agent from the reservoir, and a detection assembly (21) configured to detect a fire in the propulsion assembly (10) to which the fire extinguishing system (20) is dedicated and, if appropriate, emit a fire warning signal (S_Fire) intended for a visual or acoustic transducer (25) located in the cockpit, characterised in that The propulsion assembly (10) comprises a first compartment and a second compartment (K1, K2), each compartment comprising at least one fire zone (Z1, Z2), and is characterized in that the fire extinguishing system (20) comprises a bypass valve (26) controlled by a positioning unit (27), a set of pipes connecting each reservoir (R1, R2) to each of the fire zones (Z1, Z2) via the bypass valve (26), the positioning unit (27) being configured to detect a fire in the one or more fire zones (Z1, Z2) in the first compartment (K1) and, if appropriate, to control the bypass valve (26) so that the bypass valve adopts a first state, referred to as the controlled state, otherwise the bypass valve (26) is controlled to adopt a second state, referred to as the default state, in which, upon activation of the control element ( C1, C2), the fire extinguishing agent in the reservoir (R1, R2) is discharged toward the one or more fire zones in the first compartment (K1), and in the second state, after the control element (C1, C2) associated with the reservoir (R1, R2) is activated, the fire extinguishing agent in the reservoir (R1, R2) is discharged toward the fire zone in the second compartment (K2), wherein the bypass valve (26) includes an inlet (26a) connected to each of the reservoirs (R1, R2), and two outlets (26b, 26c), wherein the first outlet (26b) is connected to a pipe leading to the one or more fire zones (Z1, Z2) in the first compartment (K1), and the second outlet (26c) is connected to a pipe leading to the one or more fire zones (Z1, Z2) in the second compartment (K2).

2. The aircraft (A) according to claim 1, characterized in that The detection assembly (21) comprises a detection unit (22) to which a plurality of detection circuits (L) are connected, wherein each detection circuit (L) comprises at least one portion dedicated to each of the fire zones (Z1, Z2) in the propulsion assembly (10), and wherein each portion comprises at least one fire sensor (23, 24).

3. The aircraft (A) according to claim 2, characterized in that The detection unit (22) is configured to measure an electrical value of a circuit formed by each of the detection circuits (L) and to issue a warning signal (S_Fire) if the measured value has a value indicating a fire.

4. An aircraft (A) according to any one of claims 2 and 3, characterized in that The locating unit (27) is electrically connected to one or more parts of the detection circuit (L) dedicated to the fire zone (Z1, Z2) in the first compartment (K1).

5. The aircraft (A) according to claim 4, characterized in that The locating unit (27) is configured to measure the electrical value of the circuit formed by the one or more parts of the detection circuit (L) dedicated to the fire zone (Z1, Z2) in the first compartment (K1) and to send a control signal (S_Com) to the bypass valve (26) to control the valve (26) so that if the signal has a value indicating a fire in the first compartment (K1), the valve adopts its controlled state.

6. The aircraft (A) according to claim 3 or claim 5, characterized in that The electrical value is the resistance.

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