FR3137371A1 - PROPULSIVE ASSEMBLY OF AN AIRCRAFT INCLUDING A FIRE-FIGHTING SYSTEM WITH AN EXTINGUISHING AGENT DISTRIBUTION LINE. - Google Patents

Abstract

PROPULSIVE ASSEMBLY OF AN AIRCRAFT COMPRISING A FIRE-FIGHTING SYSTEM WITH AN EXTINGUISHING AGENT DISTRIBUTION LINE The invention relates to a propulsion assembly comprising a fire-fighting system comprising two extinguishing agent tanks under pressure and a distribution line (10 ) connecting each of the tanks to at least one nozzle, the distribution line (10) having at least one low point (21) and for each low point (21), a drainage valve (30) comprising a hollow body (31) connected at one of its ends to the distribution line (10) and provided with a bottom (31b) at its free end, said free end being provided with at least one drainage hole (33) communicating with the exterior, the drainage valve (30) comprising a closing device (34) arranged in the body (31), the closing device (34) being an elastically deformable element (36, 36a), made of elastomeric material, movable relative to the body (31) between a rest position in which a fluid circulates from the distribution line (10) towards the at least one drainage hole (33) and a stress position, in which said deformable element is deformed by compression and pressed against the bottom (31b) and closes all of the drainage holes, the stress position being reached when the pressure in the distribution line (10) is greater than or equal to a predetermined pressure. Fig. 3

Description

PROPULSIVE ASSEMBLY OF AN AIRCRAFT INCLUDING A FIRE-FIGHTING SYSTEM WITH AN EXTINGUISHING AGENT DISTRIBUTION LINE.

The present invention relates to an aircraft propulsion assembly comprising a fire-fighting system with a distribution line for distributing a pressurized extinguishing agent.

In known manner, a propulsion assembly fixed under the wing of an aircraft comprises a turbomachine, a mast for fixing the turbomachine to the aircraft as well as a fire-fighting system for detecting and extinguishing a fire occurring on the assembly propulsive.

The fire-fighting system contains two extinguishing agent tanks with controlled opening which are arranged in the mast, a distribution line, in the form of piping, connecting the tanks to the fire zones of the turbomachine, and a detection and control assembly. activation to detect a fire and control the opening of the tanks in order to trigger the emission of extinguishing agent from the tanks towards the fire zones through the distribution line.

The space available in the mast for the passage of the fire-fighting system distribution line is limited and constrained by the presence of a plurality of systems. On certain aircraft, it is not possible to route the extinguishing agent distribution line without locally generating at least one low point.

The distribution line being a standby line, it is filled with ambient air which enters from the fire zones. This air contains moisture which condenses and accumulates at the low points of the distribution line, and freezes when the aircraft flies at high altitude, thereby preventing the proper functioning of the fire-fighting system. A drainage valve is arranged at each low point to evacuate, by gravity, any water that could accumulate there.

Patent application EP3933183 describes a drainage valve which comprises a hollow body arranged under the distribution line and in communication with the interior of the distribution line through a hole made on the distribution line. A shutter mechanism, of the metal leaf spring type riveted inside the hollow body or of the stem valve type coupled to elastic return means arranged in the hollow body, is movable under the effect of the pressure prevailing in the distribution line, between a rest position in which the closing mechanism allows the passage of fluid out of the body towards the outside and a constraint position in which the closing mechanism closes the fluid passage. The shutter mechanism takes its constraint position when the pressure in the distribution line becomes greater than or equal to a predetermined pressure, resulting from the opening of one of the extinguishing agent tanks.

Such a drainage valve is advantageous in that it allows the water which could accumulate at the low point of the distribution line to be drained and limits the loss of extinguishing agent from the fire-fighting system as long as the extinguishing agent flows, with sufficient pressure, in the distribution line towards a fire zone.

An objective of the invention is to find a drainage valve having advantages similar to that described above, but which has a simpler design in order to be more easily installed or uninstalled by operators.

The invention aims to respond in whole or in part to this need and relates to a propulsion assembly comprising a turbomachine attached to a mast, and a fire-fighting system, the turbomachine comprising a plurality of fire zones, the fire-fighting system comprising two tanks of extinguishing agent under pressure located in the mast and a distribution line connecting each of the tanks to at least one nozzle located in each of the fire zones, the distribution line having at least one low point between the tanks and the nozzles, and for each low point, a drainage valve comprising a hollow body connected at one of its ends to the distribution line and provided with a bottom at its free end, said free end being provided with at least one communicating drainage hole with the outside, the drainage valve comprising a device for closing off the circulation of fluid arranged in the body, the closing device being constituted by an elastically deformable element, made of elastomeric material, movable relative to the body between a rest position in which a fluid circulates from the distribution line towards the at least one drainage hole and a stress position, in which the elastically deformable element is deformed by compression and pressed against the bottom of the body and closes all of the drainage holes, the stress position being reached when the pressure in the distribution line is greater than or equal to a predetermined pressure.

The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings, among which:

there , is a schematic representation of a propulsion assembly of an aircraft which comprises a pressure extinguishing agent distribution line according to the invention;

there is a sectional view of a drainage valve of the distribution line of the in a rest position, according to a first embodiment of the invention;

there is a view similar to the of a drainage valve of the distribution line of the in a constrained position, according to a first embodiment of the invention.

there is a sectional view of a drainage valve of the distribution line of the in a rest position, according to a second embodiment of the invention;

there is a view similar to the of the drainage valve of the distribution line of the in a constrained position, according to a second embodiment of the invention;

there is a sectional view of the drainage valve of the distribution line of the in a rest position, according to a third embodiment of the invention;

there is a view similar to the of the drainage valve of the distribution line of the in a constrained position, according to a third embodiment of the invention.

With reference to Figures 1 to 3, a propulsion assembly 1 is hung under the wing of an aircraft (not shown) and comprises a turbomachine 2 comprising a nacelle 3 surrounding an engine 4, a mast 5 fixed to the wing and under which the turbomachine 2 is attached, as well as a fire-fighting system 6.

The turbomachine 2 comprises a plurality of fire zones Z1, Z2, separated from each other by walls and fire joints (not shown) to contain a fire within the limits of a fire zone and prevent its propagation towards another fire zone.

The fire-fighting system 6 is designed to detect and extinguish, by sending an extinguishing agent, any fire that could occur in one of the fire zones. Conventionally, the fire-fighting system 6 contains two tanks R1, R2 with controlled opening and each containing a volume of extinguishing agent under pressure, a distribution line 10 of extinguishing agent connecting each of the tanks R1, R2 to at least a extinguishing agent ejection nozzle (not shown) located in each of the fire zones Z1, Z2, and a detection and activation unit 11 for detecting a fire and controlling the opening of the tanks.

Each tank R1, R2 is located in mast 5 and is equipped with an opening system to release the extinguishing agent out of the tank. The opening system (not shown) is for example a butterfly valve type, or a percustable pyrotechnic type.

The detection and activation unit 11, of the central unit type, is connected to a plurality of fire sensors located in the fire zones Z1, Z2 and configured to detect a fire in the latter, to the tank opening systems for control its opening, as well as the aircraft controls. When a fire is detected, the detection and activation unit 11 sends a fire alarm signal to the pilots who can act on the controls to send a signal to open the tanks. When a tank is opened, the released extinguishing agent moves under pressure in the distribution line 10 and is expelled into the fire zones Z1, Z2 through the ejection nozzles.

The distribution line 10 comprises piping made up of pipes 20 and other hydraulic connection elements (fittings, etc.) connected to each other to ensure the circulation of the extinguishing agent inside the distribution line 10. The distribution line distribution 10 includes one or more low points 21 (only one shown). A low point 21 is a point on the distribution line 10 where fluids tend to accumulate, under the effect of gravity, due to the lower height of this point compared to the points on the distribution line 10 directly located upstream and downstream of the low point 21. The terms upstream and downstream being chosen according to the direction of flow of the extinguishing agent in the distribution line 10, that is to say from the tanks R1, R2 towards the nozzles.

In known manner, the distribution line 10 comprises a drainage valve 30 arranged at each low point 21. The drainage valve 30 comprises, particularly visible in Figures 2 and 3:

- a hollow body 31, of cylindrical shape and whose longitudinal axis X is oriented orthogonally to the ground. The body 31 is connected at one of its ends 31a to the distribution line 10 and has a bottom 31b at the opposite end, i.e. the free end. One or more drainage holes 33 are arranged at the free end of the body 31, where fluids (e.g. water) tend to accumulate under the influence of gravity to allow fluids to flow towards the outside of the body 31. A fluid passage P is thus defined between the distribution line 10 and the outside of the body 31, this fluid passage P traveling through the distribution line 10, the body 31 and the drainage hole(s) 33 of the body;

- a device 34 for closing the fluid passage P, arranged inside the body 31.

Here, the distribution line includes a connector for fixing the hollow body 31, which is here screwed onto the connector. In detail, the side wall 31c of the body is screwed, over only part of its height, to the distribution line. A space is thus defined between the bottom 31b of the body and the distribution line 10.

According to the invention, the shutter device 34 is constituted by a single elastically deformable element 36, made of elastomeric material. The elastically deformable element 36 is movable relative to the hollow body 31 between a rest position in which a fluid circulates from the distribution line 10 towards the at least one drainage hole 33 and a stress position, in which the element elastically deformable 36 is deformed by compression and pressed against the bottom 31b of the body and closes all of the drainage holes 33 to prevent the circulation of the fluid, the stress position being reached when the pressure in the distribution line 10 is greater than or equal to at a predetermined pressure.

In a first embodiment of the invention illustrated in relation to Figures 2 and 3, the drainage holes 33 of the body 31 take the form of a plurality of perforations, arranged at the junction of the bottom 31b and the side wall 31c of the body, to allow the evacuation of liquids to the outside. The perforations take, for example, the form of slots.

The elastically deformable element 36 is an elastomer bellows 36a constituted by a hollow part of revolution composed of a central part 37 comprising a plurality of turns placed end to end along the longitudinal axis of the central part 37 which coincides with the longitudinal axis , facing the bottom of the body 31, and which closes the bellows 36a at this end.

The end piece 38 is hollow, cylinder-shaped and includes a collar at its free longitudinal end. The collar is inserted into a circular groove arranged on the interior surface of the distribution line 10 (here, more precisely, on the interior surface of the connector on which the body 31 is fixed) then fixed to the latter by gluing or any other means equivalent, to join the bellows and the distribution line. The connection between the end piece 38 and the distribution line 10 is airtight and watertight.

The central part 37 is dimensioned (number of turns, heights of turns in the rest position and thickness of the walls of the central part) to extend from its rest position, parallel to its longitudinal axis, when a force is exerted on its second end to move it away from its first end. The central part 37 can extend to a maximum of an extension distance d from its rest length.

The partition 39 is slightly curved and the bottom 31b of the body is on the convex side of the partition 39. The partition 39 is provided with a through hole 40, arranged at the lowest point of the partition 39, here at the level of the longitudinal axis of the bellows 36a when the latter is in the rest position. The through orifice 40 has a diameter greater than 1 millimeter, typically a diameter of the order of 1 to 6 millimeters, to allow the passage of fluids and therefore the evacuation of fluids from the bellows 36a by gravity.

The fluid passage P passes through the interior of the bellows 36a.

The bellows 36a is positioned and dimensioned such that in its rest position, the smallest distance between the partition 39 and the bottom 31b of the body is less than the elongation distance d, for example half the distance d elongation d.

The partition 39 forms a narrowing, and therefore an obstacle, for the passage of air from the distribution line 10 to the outside of the body 31 through the perforations 33. The pressure of the air in the distribution line 10 exerts a force on the partition 39 which tends to lengthen the central part 36 of the bellows by bringing the partition 39 closer to the bottom 31b of the body.

In the nominal case, when the distribution line 10 is filled with ambient air (normal configuration where there is no percussion of one of the tanks R1, R2), the value of this force is negligible. In this case, the bellows 36a takes its rest position, in which it is not deformed and the partition 39 is located at a distance from the bottom 31b of the body. The fluid passage P is open and a fluid, such as water, can flow from the distribution line 10 to the outside passing through the through hole 40 of the bellows partition and the perforations of the body.

When a tank R1, R2 is open, the pressure in the distribution line 10 temporarily takes a value of around 1000 psi until the tank empties. In this case, the force exerted by the pressure wave which moves in the distribution line 10 and coming from the sudden expansion of the gases released from the open tank R1, R2, exerts a force on the partition 39 of the bellows 36a and the latter which takes its constrained position and has just pressed against the bottom 31b of the body, thereby closing the fluid passage P.

When the pressure in the distribution line decreases (that is to say when all of the extinguishing agent from a hit tank has been released in the fire zones), the force exerted on the partition 39 decreases and the bellows 36a returns to its rest position. The fluid passage P is opened again for the evacuation of fluids other than the extinguishing agent.

The drainage valve 21 according to the invention comprising only one part is simple to install and uninstall. In particular, after separation from the body of the distribution line, the sleeve 36a can be removed or replaced easily, without the need for complex operations.

With reference to Figures 4 and 5, and in a second embodiment of the invention, the drainage holes 33 of the body 31 take the form of a plurality of perforations, arranged on its bottom 31b and arranged in a circle around the center of the bottom 31b, to allow the evacuation of fluid to the outside. These perforations 33 take, for example, the shape of an orifice with a minimum diameter of 1 millimeter.

The elastically deformable element 36 is here an elastomer membrane 36b, having at rest a curved pre-stressed shape with an outer circumferential edge 41 fixed to the distribution line 10. In detail, the outer circumferential edge 41 of the membrane is inserted into a circular groove arranged on the distribution line (here, the connector onto which the body is screwed) then fixed to the latter by gluing or any other equivalent means to secure the membrane 36b and the distribution line. The connection between the membrane 36b and the distribution line 10 is watertight and airtight.

The membrane 36b extends between the bottom 31b of the body and the distribution line and the bottom 31b is on the convex side of the membrane 36b when the latter is in the rest position. In the rest position of the membrane 36b, there is a space allowing the passage of fluid between the membrane 36b and the bottom 31b of the body.

The membrane 36b is provided with a through orifice 42, arranged at the lowest point of the membrane in the rest position, that is to say directly above the center of the bottom 31b. The through orifice 42 has a diameter greater than 1 millimeter, typically a diameter of the order of 1 to 6 millimeters, which allows the passage of fluids and therefore their evacuation from the membrane by gravity. The edge of the through hole 42 forms the inner circumferential edge of the membrane 36b.

The passage of fluid P passes through the through orifice 40 of the membrane 36b.

The membrane 36b forms a constriction, and therefore an obstacle, for the passage of air from the distribution line 10 to the outside of the body 31 through the perforations 33. The pressure of the air in the distribution line 10 exerts a force on the membrane 36b which tends to deform it by bringing its inner circumferential edge closer to the bottom 31b of the body.

The membrane 36b is positioned and dimensioned such that in its rest position, the smallest distance between its inner circumferential edge and the bottom 31b of the body is less than the maximum distance d to which the membrane 36b can extend from from its rest position.

In the nominal case, when the distribution line 10 is filled with ambient air (normal configuration where there is no opening of one of the tanks), the value of the force exerted by the pressure on the membrane 36b is negligible. In this case, the membrane 36b takes its rest position, in which it is not deformed and its lower circumferential edge is located at a distance from the bottom 31b of the body, at least 1 millimeter from the bottom 31b. The fluid passage P is open since a liquid can flow from the distribution line to the outside passing through the through orifice 42 of the membrane 36b and the perforations 33 of the body 31.

When a tank R1, R2 is open, the force exerted by the pressure wave which moves in the distribution line 10, coming from the sudden expansion of the gases released outside the impacted tank, exerts a force on the membrane 36b. Due to this force, the membrane 36b swells, which has the effect of deforming it. In its stressed position, the deformation of the membrane 36 is such that the part of the membrane 36b comprising the through orifice 42 is pressed against the bottom 31b of the body, thereby closing the perforations 33. The fluid passage P is therefore closed.

When the pressure in the distribution line 10 decreases (that is to say when all of the extinguishing agent from an open tank has been released in the fire zones Z1, Z2), the force exerted on the membrane 36b decreases and the latter returns to its rest position. The fluid passage P is opened again for the evacuation of fluids other than the extinguishing agent.

The drainage valve 21 according to this second embodiment is simple to install and uninstall. In particular, after separation from the body of the distribution line, the membrane 36b can be removed or replaced easily, without the need for complex operations.

With reference to Figures 6 and 7, and in a third embodiment of the invention, the bottom 31b of the body comprises a through orifice 43, called central orifice, arranged in its center.

The hollow body 31 comprises a plurality of drainage holes 33 in the form of perforations arranged on the bottom 31b and arranged in a circle around the central orifice 43, to allow the evacuation of fluids to the outside. Each of the perforations takes, for example, the shape of an orifice with a minimum diameter of 1 millimeter.

The elastically deformable element 36 is here an umbrella valve 36c which comprises a veil 36c1 supported by a rod 36c2. The 36c1 veil and the 36c2 stem are made in one piece, with an umbrella shape.

The rod 36c2 is force-fitted into the central orifice 43 of the bottom 31b of the body in order to secure the umbrella valve 36c to the bottom 31b of the body.

The 36c1 web is pre-loaded so as to have, in the rest position, a curved disc shape. The bottom 31b of the body is on the concave side of the veil 36c. The dimensions of the 36c umbrella valve are such that:

- in the rest position, the outer circumferential edge 45 of the veil is located at a distance from the bottom 31b of the body, at least several millimeters, and at a distance from the side wall 31c of the body, in order to allow the passage of fluid; And

- in the constrained position, the web 36c is located directly above the perforations 33 of the bottom 31b of the body and the outer circumferential edge 45 of the web 36c is entirely in contact with the bottom 31b of the body, thereby closing the fluid passage P.

The veil 36c forms an obstacle for the passage of air from the distribution line 10 towards the outside of the body 31 through the perforations 33. The pressure of the air in the distribution line 10 exerts a force on the veil 36c which tends to deform it by compressing it towards the bottom 31b of the body. During this deformation, the outer circumferential edge 45 approaches the bottom of the body.

In the nominal case, when the distribution line 10 is filled with ambient air (normal configuration where there is no opening of one of the tanks R1, R2), the value of the force exerted by the pressure of the The air on the veil 36c is negligible. In this case, the web 36c takes its rest position, in which it is not deformed. Fluid passage P is open.

When a tank R1, R2 is open, the force exerted by the pressure wave which moves in the distribution line 10, coming from the sudden expansion of the gases released outside the open tank, exerts a force on the veil 36c which takes its constrained position and presses it, at the level of its outer circumferential edge 45, against the bottom 31b of the body, thereby closing the air passage P.

When the pressure in the distribution line 10 decreases (that is to say when all of the extinguishing agent from an open tank has been released into the fire zones), the force exerted on the veil 36c decreases and this last returns to its rest position. The fluid passage P is opened again for the evacuation of fluids other than the extinguishing agent.

The drainage valve 21 according to the third embodiment is simple to install and uninstall. In particular, after separation of the body from the distribution line, the rod 36c2 can be easily removed from the body by disconnecting it from the central orifice 43. The reverse operation is just as simple for operators.

In the embodiments described above, the elastomeric material used is for example fluorosilicone which is resistant to solvents, oils and other contaminants.

Claims (4)

Propulsion assembly (1) comprising a turbomachine (2) attached to a mast (5), and a fire-fighting system (6), the turbomachine (2) comprising a plurality of fire zones (Z1, Z2), the fire-fighting system fire (6) comprising two tanks (R1, R2) of extinguishing agent under pressure located in the mast (5) and a distribution line (10) connecting each of the tanks (R1, R2) to at least one nozzle located in each fire zones (Z1, Z2), the distribution line (10) having at least one low point (21) between the tanks (R1, R2) and the nozzles, and for each low point (21), a drainage valve (30) comprising a hollow body (31) connected at one of its ends to the distribution line (10) and provided with a bottom (31b) at its free end, said free end being provided with at least one drainage hole (33) communicating with the outside, the drainage valve (30) comprising a device (34) for closing off the circulation of fluid arranged in the body (31), characterized in that the closing device (34) is constituted by an elastically deformable element (36, 36a-c), made of elastomeric material, movable relative to the body (31) between a rest position in which a fluid circulates from the distribution line (10) towards the at least one drainage hole (33) and a stress position, in which the elastically deformable element (36) is deformed by compression and pressed against the bottom (31b) of the body and closes all of the drainage holes, the stress position being reached when the pressure in the distribution line (10) is greater than or equal to a predetermined pressure. Propulsion assembly (1) according to claim 1, characterized in that the body (31) is of cylindrical shape with a side wall (31c) of circular section fixed to the distribution line (10) and comprises a plurality of drainage holes (33) arranged at the junction of the bottom (31b) and the side wall (31c) of the body (31), the elastically deformable element (36) is a bellows (36a) arranged between the bottom (31b) of the body and the distribution line (10), the bellows (36a) taking the form of a hollow part of revolution composed of a central part (37) extending longitudinally parallel to a longitudinal axis (X) of the body (31) and comprising a plurality of turns placed end to end, a tip (38) located at a first end of the central part (37) and fixed to the distribution line (10) and a partition (39) provided with a through orifice (40) located at a second end of the central part (37), facing the bottom of the body (31b), and in that, in the rest position of the bellows (36a), a space separates the bottom (31b) of the body of the partition (39) and the smallest distance between the partition (39) and the bottom (31b) of the body is less than a maximum elongation distance of the bellows (36a). Propulsion assembly (1) according to claim 1, characterized in that the body (31) is of cylindrical shape with a side wall (31c) of circular section fixed to the distribution line (10), and comprising a plurality of holes drainage (33) arranged on the bottom (31b) of the body and arranged in a circle around the center of the bottom (31b) of the body (31), the elastically deformable element (36) is a membrane (36b) arranged between the bottom ( 31b) and the flange (35), the membrane (36b) having an outer circumferential edge fixed to the distribution line (10), the membrane (36b) having in the rest position a pre-stressed curved shape with the bottom (31b) of the body located on the convex side of the membrane (36b), the membrane (36b) being provided with a through orifice (42) arranged at the lowest point of the membrane (36b) and directly above the center of the bottom ( 31b) of the body, and in that, in the rest position of the membrane (36b), a space separates the bottom (31b) of the body of the membrane (36b) and the smallest distance between the membrane (36b) and the bottom (31b) of the body is less than a maximum elongation distance of the membrane (36b). Propulsion assembly (1) according to claim 1, characterized in that the body (31) is of cylindrical shape with a side wall of circular section fixed to the distribution line (10), and comprising a through orifice (43), called central orifice, arranged in the center of the bottom (31b) of the body and a plurality of drainage holes (33) arranged on the bottom (31b) of the body and arranged in a circle around the central orifice (43), the deformable element elastically (36) is an umbrella valve (36c) comprising a sail (36c1) supported by a rod (36c2) inserted in the central orifice (43) and secured to the bottom (31b) of the body, the sail (36c1) having a curved disc shape in the rest position and the bottom (31b) of the body being on the concave side of the veil (36c), and in that in its rest position, the veil (36c1) is located directly above the holes drainage (33) and an outer circumferential edge of the veil (36c1) is at a distance from the side wall (31c) and the bottom (31b) of the body (31).