Curved fire extinguisher for an engine

Abstract

The invention relates to a fire extinguisher (1) comprising at least: - a body forming a container extending longitudinally between a first end (2b) and a second end (2c) and enclosing a storage chamber (4) and a pressurization chamber (3) separated by a piston (5) adapted to slide within said body (2) between the first end (2b) and the second end (2c) of said body (2), an extinguishing agent being present in the storage chamber (4), and the storage chamber (4) comprising at least one outlet orifice (10), and - a gas generator adapted to generate a gas in the pressurization chamber (3). The piston (5) comprises the gas generator, and the body (2) has a longitudinally curved shape between its first end (2b) and its second end (2c), the piston (5) having a curvilinear stroke between the first end (2b) and the second end (2c) of the body (2).

Description

Technical Field

[0001] The present invention relates to an engine fire extinguisher comprising an extinguishing agent. Prior art

[0002] Extinguishing engine fires is a problem encountered particularly in the aeronautical field, for example when trying to extinguish a fire in an aircraft engine.

[0003] Aircraft engine fire extinguishers are typically equipped with systems such as cylinders of extinguishing agent pressurized to approximately 200 bar. Such systems are kept away from the engine, outside the nacelle. The extinguishers are typically held in position by fasteners and connected to the engine compartment by hoses, to limit the extinguishers' direct exposure to the high thermal stresses of the engine environment.

[0004] These systems traditionally use Halon gas as an extinguishing agent, removing oxygen to contain the fire. Halons have the advantage of ensuring satisfactory extinguishment while maintaining a reduced mass. However, Halons are polluting products, which have a high ozone depletion potential (ODP) and whose use is subject to increasingly strict regulatory bans. The use of Halons as an extinguishing agent therefore represents an environmentally unsatisfactory temporary solution that should be replaced. Halons also have the disadvantage of having a high global warming potential.

[0005] This gaseous agent is stored in tanks positioned in the mast of each engine. Metal pipes are connected to them. They separate into several injection points in the upper part of the nacelle. The injection is therefore carried out in an untargeted manner and floods the entire engine.

[0006] It is possible to replace existing fire extinguishers with pyrotechnic fire extinguishers using a non-polluting extinguishing agent in liquid form, but with a mass of agent required to achieve the desired concentration that is twice that of Halon. An example of this type of fire extinguisher is known from document US 2021 / 101036 A1. Statement of the invention

[0007] The aim of the invention is to provide a pyrotechnic extinguisher using a non-polluting extinguishing agent in the liquid state which can be integrated into the nacelle of an engine to act as close as possible to the engine and thus extinguish a fire without flooding the engine and limiting as much as possible the masses of the extinguisher accessories, but limiting to a minimum the aerodynamic disturbances of the air flow circulating in the vein of the engine in which the extinguisher is integrated.

[0008] An object of the invention provides a fire extinguisher comprising at least: a body forming an enclosure extending longitudinally between a first end and a second end and enclosing a storage chamber and a pressurization chamber separated by a piston capable of sliding in said body between the first end and the second end of said body, an extinguishing agent being present in the storage chamber, and the storage chamber comprising at least one outlet orifice, and a gas generator capable of generating a gas in the pressurization chamber.

[0009] According to a general characteristic of the invention, the piston comprises the gas generator, and the body has a longitudinally curved shape between its first end and its second end, the piston having a curvilinear stroke between the first end and the second end of the body.

[0010] The longitudinally curved shape of the body allows it to match the shape of the external wall of the vein where the extinguisher will be installed in the engine and thus to limit as much as possible the disturbances of the air flow in the vein.

[0011] Integrating the extinguisher into the engine's air stream thus maximizes extinguishing efficiency and reduces the volume of extinguishing agent required for extinguishing.

[0012] By placing the gas generator in the piston, it is protected by the air or gas present in the pressurization chamber, which acts as a thermal insulator. The gas generator is therefore protected from thermal stresses external to the fire extinguisher by being inserted between a gaseous canopy of the pressurization chamber and the extinguishing agent of the storage chamber. The extinguishing agent has a strong endothermic power, which makes it an excellent thermal insulator. Thus, the extinguisher is very compact, and can be integrated as close as possible to the engine, which limits the number of fasteners and pipes required, and thus lightens the overall device. In particular, such a fire extinguisher placed near the engine is still operational after 15 minutes of fire in the engine.

[0013] In a first aspect of the fire extinguisher, the piston may have a shape without central symmetry, such as an oblong shape or a figure eight shape.

[0014] The shape without central symmetry prevents any rotation of the piston around its axis and thus eliminates the risk of the piston getting stuck in the body enclosure.

[0015] In a second aspect of the fire extinguisher, the piston may have a longitudinally curved profile corresponding to the longitudinal curvature of the body.

[0016] The curved shape of the piston in the longitudinal direction makes it easier to slide the piston in the body enclosure in the longitudinal direction between the first end and the second end of the body.

[0017] In a third aspect of the fire extinguisher, the body may include a plurality of outlet ports.

[0018] The multiple outlet ports allow for precise targeting of different areas of the engine, and faster filling of the volume.

[0019] In a fourth aspect of the fire extinguisher, the extinguisher may further comprise at least one injection ramp coupled to an outlet port.

[0020] The injection ramp allows the extinguishing agent to be delivered more quickly to areas remote from the extinguisher without waiting for the cavity to be treated to be filled.

[0021] In a fifth aspect of the fire extinguisher, at least one injection ramp may comprise at least one tube pierced with a plurality of spray orifices.

[0022] The tubes can have a circular, square or other shape.

[0023] In a sixth aspect of the fire extinguisher, each spray orifice of a tube is provided with a spray nozzle or orifice acting as a nozzle.

[0024] In one variant, the piston may comprise a thermal insulation housing in which the gas generator is present, the housing being inserted between the pressurization chamber and the storage chamber, the housing opening into the pressurization chamber.

[0025] The thermal insulation housing defines a protruding portion into the storage chamber and the gas generator is surrounded by the extinguishing agent.

[0026] The housing in which the gas generator is located is in this case insulated on all sides, thus further improving the resistance of the gas generator in a fire environment.

[0027] According to another embodiment of the invention, the gas generator is a pyrotechnic gas generator.

[0028] The use of a pyrotechnic gas generator is advantageous over the use of a pressurized gas cylinder in order, on the one hand, to limit the temperature sensitivity of the generated pressure and, on the other hand, to obtain an extinguishing agent pressure profile as a function of time making it possible to obtain extinguishing agent concentration values as a function of time as close as possible to the minimum necessary extinguishing agent concentration values, thus further improving extinguishing efficiency in an engine environment.

[0029] The invention further relates to an aircraft engine equipped with at least one fire extinguisher as described above.

[0030] According to a particular embodiment of the aircraft engine, the engine is an aircraft engine comprising a nacelle, the fire extinguisher being integrated into the nacelle.

[0031] By integrating the extinguisher(s) directly into the nacelle, the number of fasteners and pipes required to install the extinguisher(s) is limited, and the total mass of the extinguisher is thus limited. This allows the extinguisher(s) described above to be positioned as close as possible to the engine.

[0032] According to a particular embodiment of the aircraft engine, at least one tube of an injection rail is fixed to the nacelle using metal supports and extends in the engine in a direction parallel to an axis of revolution of the engine.

[0033] According to a particular embodiment of the aircraft engine, at least one tube of an injection rail can be fixed to the nacelle using metal supports and extend around the engine forming a ring.

[0034] The invention also relates to a method for extinguishing a fire in an aircraft engine using at least one fire extinguisher as described previously. Brief description of the drawings

[0035] [ Fig. 1 ] There figure 1 is a schematic perspective view of an example of a fire extinguisher according to a first embodiment of the invention. Fig. 2 ] There figure 2 is a schematic longitudinal sectional view of the fire extinguisher of the figure 1 . [ Fig. 3 ] There figure 3 is a schematic perspective view of the piston 5 of the fire extinguisher of the figure 1 . [ Fig. 4 ] There figure 4 is a schematic side view of the piston 5 of the fire extinguisher of the figure 1 . [ Fig. 5 ] There Figure 5 is a schematic longitudinal sectional view of an aircraft engine provided with fire extinguishers according to a second embodiment. Fig. 6 ] There figure 6is a schematic longitudinal sectional view of an aircraft engine provided with fire extinguishers according to a third embodiment. Description of the embodiments

[0036] THE Figures 1 and 2 illustrate a perspective view and a sectional view of an example of a fire extinguisher 1 according to a first embodiment of the invention.

[0037] The fire extinguisher 1 comprises a body 2 extending longitudinally between a first end 2b and a second end 2c. The body 2 is hollow and forms an enclosure 2a enclosing a pressurization chamber 3 and a storage chamber 4. The body 2 also encloses a piston 5, which separates the pressurization chamber 3 and the storage chamber 4.

[0038] The enclosure 2a formed by the body 2 extends along the curvilinear longitudinal axis CX represented by the axis line on the figure 2and surrounds the storage chamber 4 and the pressurization chamber 3. The piston 5 slides in the body 2 in contact with the enclosure 2a of said body 2. The body 2 further comprises a first bottom wall 21 at its first end 2b as well as a second bottom wall 22 at its second end 2c. The first and second bottom walls 2b and 2c longitudinally delimit the body 2.

[0039] The first bottom wall 21 delimits the pressurization chamber 3 while the second bottom wall 22 delimits the storage chamber 4, the pressurization chamber 3 and the storage chamber 4 being separated from each other by the piston 5. The pressurization chamber 3 is therefore located between the piston 5 and the first bottom wall 21. The storage chamber 4 is located between the second bottom wall 22 and the piston 5. Consequently, the pressurization chamber 3 is delimited by the enclosure 2a of the body 2, by the first bottom wall 21 and by the piston 5, and the storage chamber 4 is delimited by the enclosure 2a of the body 2, by the second bottom wall 22 and by the piston 5.

[0040] The piston 5 is able to slide longitudinally in the body 2 between the first end 2b and the second end 2c. The sliding of the piston 5 in the body 2 makes it possible to vary the volume of the pressurization chamber 3 and the storage chamber 4. The piston 5 can slide along a curvilinear displacement axis coinciding with the curvilinear longitudinal axis CX of the body 2.

[0041] In the example illustrated on the Figures 1 and 2 , the second bottom wall 22 comprises an outlet orifice 10 configured to eject extinguishing agent outside the body 2. In a variant, the second bottom wall 22 may comprise several outlet orifices 10.

[0042] As illustrated in the figure 1, in a section plane orthogonal to the direction of the curvilinear longitudinal axis CX of the body 2, the enclosure 2a formed by the body 2 has a shape without axial symmetry, and more particularly the enclosure 2a has an overall shape of eight. In other words, a pinched shape in the middle. This shape without axial symmetry in a section plane orthogonal to the curvilinear longitudinal axis CX of the body 2 and therefore orthogonal to the curvilinear axis of movement of the piston 5 makes it possible to prevent the piston from getting stuck during its movement in the enclosure 2a.

[0043] THE Figures 3 and 4 respectively present a perspective view and a side view of the piston of the fire extinguisher 1 of the Figures 1 and 2 .

[0044] As illustrated in 3 and 3, the piston 5 comprises a first wall 51 and a second wall 52 distant from the first wall 51 and connected to the first wall 51 via a third wall 53 extending between the first wall 51 and the second wall 52. The piston 5 thus forms a closed polyhedron.

[0045] The first wall 51 of the piston 5 faces the pressurization chamber 3 and faces the first bottom wall 21 of the body 2. The second wall 52 of the piston 5 faces the storage chamber 4 and faces the second bottom wall 22 of the body 2.

[0046] As illustrated in the figure 4 , the piston 5 has a curved shape along the curvilinear longitudinal axis CX. The third wall 53 therefore does not have any notable symmetry. On the figure 4, the portion of the third wall 53 which is at the bottom is shorter than the portion of the third wall 53 which is at the top when measuring the lengths of the portions between the first wall 51 and the second wall 52.

[0047] Furthermore, as illustrated in the figure 3 , in a section plane orthogonal to the direction of the curvilinear longitudinal axis C, the piston 5 has a shape without axial symmetry, and more particularly an overall shape of eight, that is to say pinched in the middle. This shape without axial symmetry in a section plane orthogonal to the curvilinear axis of movement of the piston 5 makes it possible to prevent the piston from getting stuck during its movement in the enclosure 2a.

[0048] The piston 5 is configured to sealably separate the pressurization chamber 3 from the storage chamber 4. The piston 5 extends over the entire internal section of the storage chamber 4. The piston 5 preferably comprises a sealing system 54 for providing a seal between the pressurization chamber 3 and the storage chamber 4. The sealing system 54 prevents the extinguishing agent from entering the pressurization chamber 3, and prevents air or gases present in the pressurization chamber 3 from entering the storage chamber 4. The sealing system 54 illustrated in the Figures 3 and 4 comprises two seals 55 arranged continuously between the piston 5 and the body 2 and extending over the entire outer perimeter of the third wall 53 to form a sealed barrier in a plane perpendicular to the curvilinear longitudinal axis CX.

[0049] The piston 5 may be made of a metallic material, for example aluminum. Advantageously, the piston 5 may be made of a single material in order to simplify the manufacturing process of the fire extinguisher 1.

[0050] An extinguishing agent is present in the storage chamber 4. The extinguishing agent may be present in a liquid state. The extinguishing agent may be present in a gaseous state. The extinguishing agent may be FK-5-1-12 or Novec ™< 1230. For example, Novec ™< 1230 lowers the temperature of the fire in the engine environment by vaporizing at the outlet of the extinguisher and lowers the oxygen level. Novec ™< 1230 also has the advantage of being dielectric and leaving no residue.

[0051] The extinguisher comprises a gas generator which can be housed in the piston 5 and in communication with the pressurization chamber 3 to generate the movement of the piston 5 towards the second end 2c of the body 2.

[0052] The extinguisher 1 may further comprise a shutter sealingly closing the outlet orifice 10 and configured to allow the extinguishing agent to exit the body 2 when the pressure in the storage chamber 4 exceeds a predefined value. In other words, the shutter is configured to prevent, when in a first configuration, the extinguishing agent from exiting the body 2. The shutter is further configured to move into a second configuration when the pressure in the storage chamber 4 exceeds a predefined value, this second configuration of the shutter allowing the extinguishing agent to exit the body 2. The shutter may, for example, be in the form of a membrane configured to yield when the pressure in the storage chamber 4 exceeds a predefined value. In this case, the shutter may, for example, be a membrane made of aluminum or an alloy of the Inconel ® type.

[0053] The method of distributing the extinguishing agent will now be described in connection with the figure 2 . The gas generator is first actuated in order to pressurize the pressurization chamber 3. This overpressure created in the pressurization chamber 3 is transmitted by the piston 5 to the extinguishing agent present in the storage chamber 4. Once a predefined value has been reached for the pressure in the storage chamber 4, the shutter of the outlet orifice 10 passes into a second configuration allowing the exit of the extinguishing agent outside the body 2 through the outlet orifice 10. The piston 5 is set in motion towards the second bottom wall 22 in order to cause the extinguishing agent to be dispensed. The piston 5 is then set in motion along the curvilinear longitudinal axis CX. The extinguishing agent can be dispensed outside the extinguisher 1.

[0054] During the dispensing of the extinguishing agent, the volume of the pressurizing chamber 3 increases and the volume of the storage chamber 4 decreases. The sum of the volume of the pressurizing chamber 3 and the volume of the storage chamber 4 is constant during the dispensing of the extinguishing agent. The piston 5 is configured to move without deforming during the dispensing of the extinguishing agent. The first wall 51 of the piston 5 is subjected to the pressure of the generated gas, this pressure is communicated to the second wall 52 of the piston 5 in order to allow the dispensing of the extinguishing agent outside the body 2. The piston 5 causes, during its movement, the dispensing of the extinguishing agent outside the body 2 in the manner of a syringe.

[0055] Fire extinguisher 1 is particularly useful for extinguishing fires in an aircraft engine.

[0056] There Figure 5illustrates an example of an aircraft engine 100 comprising fire extinguishers 1 according to a second embodiment of the invention. The example of an aircraft engine 100 is a twin-spool, twin-flow aircraft turbomachine comprising, from upstream to downstream, in the direction of flow of the air flow, a fan 200, a low-pressure compressor 300, a high-pressure compressor 400, a combustion chamber 500, a high-pressure turbine 600, and a low-pressure turbine 700. However, the invention can be applied to a turbomachine having a different structure. The primary flow is delimited by an inner casing 800, and the secondary flow is delimited by the inner casing 800 and by an outer casing 900. The outer casing 900 comprises the fan casing.

[0057] The fire extinguisher(s) 1 may be arranged on the internal face of the external casing 900, or on the external face of the casing 800, close to the combustion chamber 500 or the compressors 300, 400, the external casing forming part of the nacelle of the aircraft engine 100.

[0058] On the Figure 5 the fire extinguisher 1 further comprises an injection ramp 58 coupled to the outlet orifice 10 and comprising a tube extending into the aircraft engine 100 in a direction parallel to the axis of revolution of the aircraft engine.

[0059] There figure 6 illustrates an example of an aircraft engine 100 comprising fire extinguishers 1 according to a third embodiment of the invention. This embodiment differs from that of the Figure 5in that the fire extinguisher 1 comprises an injection ramp 59 coupled to the outlet orifice and comprising a tube extending into the aircraft engine in a circumferential direction around the axis of revolution of the aircraft engine.

[0060] In both embodiments of the Figures 5 and 6 , the tubes of the injection rails 58 and 59 comprise a plurality of spray orifices which can each be provided with a spray nozzle to define a precise spray jet shape.

[0061] The invention thus makes it possible to provide a pyrotechnic extinguisher using a non-polluting extinguishing agent in the liquid state which can be integrated into the nacelle of an engine to act as close as possible to the engine and thus extinguish a fire without flooding the engine and limiting as much as possible the masses of the extinguisher accessories, but limiting to a minimum the aerodynamic disturbances of the air flow circulating in the vein of the engine in which the extinguisher is integrated.

Claims

1. A fire extinguisher (1) comprising at least: - a body (2) forming an enclosure extending longitudinally between a first end (2b) and a second end (2c) and enclosing a storage chamber (4) and a pressurization chamber (3) separated by a piston (5) capable of sliding in said body (2) between the first end (2b) and the second end (2c) of said body (2), an extinguishing agent being present in the storage chamber (4), and the storage chamber (4) comprising at least one outlet orifice (10), and - a gas generator capable of generating a gas in the pressurizing chamber (3), characterized in that the piston (5) comprises the gas generator, and the body (2) has a longitudinally curved shape between its first end (2b) and its second end (2c), the piston (5) having a curvilinear stroke between the first end (2b) and the second end (2c) of the body (2).

2. The fire extinguisher (1) according to claim 1, wherein the piston (5) has a shape without central symmetry.

3. The fire extinguisher (1) according to one of claims 1 or 2, wherein the piston (5) has a longitudinally curved profile corresponding to the longitudinal curvature of the body (2).

4. The fire extinguisher (1) according to one of claims 1 to 3, wherein the body (2) comprises a plurality of outlet orifices (10).

5. The fire extinguisher (1) according to one of claims 1 to 4, further comprising at least one injection rail (58, 59) coupled to an outlet orifice (10).

6. The fire extinguisher (1) according to claim 5, wherein said at least one injection rail (58, 59) comprises at least one tube pierced with a plurality of spray orifices.

7. The fire extinguisher (1) according to claim 6, wherein each spray orifice of a tube is provided with a spray nozzle.

8. An aircraft engine (100) equipped with at least one extinguisher (1) according to any one of claims 1 to 7.

9. The aircraft engine (100) according to claim 8, said engine being an aircraft engine comprising a nacelle, the extinguisher (1) being incorporated into the nacelle.

10. The aircraft engine (100) according to claim 9, comprising an extinguisher (1) according to one of claims 5 to 7, and wherein at least one tube of an injection rail (58) is attached to the nacelle using metal supports and extends in the engine in a direction parallel to an axis of revolution of the engine.

11. The aircraft engine (100) according to one of claims 9 or 10, comprising an extinguisher (1) according to one of claims 5 to 7, and wherein at least one tube of an injection rail (59) is attached to the nacelle using metal brackets and extends around the engine forming a ring.

12. A method of extinguishing a fire in an aircraft engine (100) using at least one extinguisher (1) according to any one of claims 1 to 7.

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