Check valve for the gas distribution system of an aircraft, corresponding system

Description

[0001] The invention relates to an aircraft gas distribution system comprising a non-return valve. BACKGROUND OF THE INVENTION

[0002] In aircraft, for safety reasons, it is common practice to connect an inerting gas distribution system to one or more of the aircraft's fuel tanks. This inerting gas distribution system, also called an inerting system, generates an inert gas (nitrogen, carbon dioxide, etc.) which is then injected into the tank(s) to reduce the risk of explosion.

[0003] The inerting system includes at least one pipe running between the gas generator of said system and the tank(s) intended for the circulation of the inerting gas. Such a pipe is usually equipped with a non-return valve 106 as illustrated in the figure 1 Such a non-return valve 106 thus comprises a valve 109 equipped with a control rod 110, valve 109 sliding between: a closed position where the valve 109 rests on a seat 111 of a body of the check valve 106, and an open position where the valve 109 is offset from the seat 111.

[0004] A spring 112 is also arranged so that its first end is connected to the valve 109 and its second end to the body of the check valve 106 in order to keep the valve 109 in the closed position.

[0005] Thus, the non-return valve 109 allows the inerting gas to flow towards the tanks but limits the risk of fuel vapor flowing back from the tanks to the gas generator. Unfortunately, the passage of the inerting gas through the non-return valve 109 tends to generate oscillations within the valve, which consequently wears out quickly and requires regular replacement for obvious safety reasons. A similar non-return valve has been known since DE 203 00 159 U1.

[0006] On another note, climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by different countries. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively contributing to the fight against climate change for several years now. Technological research efforts have already led to significant improvements in the environmental performance of aircraft.The Applicant takes into consideration the factors impacting all phases of design and development in order 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.

[0007] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity. SUBJECT OF THE INVENTION

[0008] One aim of the invention is therefore to provide a non-return valve for an aircraft gas distribution system that wears out less quickly. SUMMARY OF THE INVENTION

[0009] For this purpose, a gas distribution system for an aircraft is provided, comprising a non-return valve, the valve comprising a valve equipped with a valve control rod, the valve being intended to slide along a first axis between a closed position where the valve cooperates in service with a seat of the distribution system and an open position where the valve is offset from the seat, the valve comprising at least a first spring arranged outside the control rod and tending in service to hold the valve against the seat.

[0010] According to the invention, the valve comprises an assembly including at least one weight and at least one second spring, which are arranged at least partially inside the control rod. The spring is connected at one of its two ends to the control rod and at the other of its two ends to the weight. A recess is provided in the control rod such that it opens at a first axial end at the level of a first end of the control rod, opposite the end connected to the valve, and is blind at a second axial end opposite the first axial end.

[0011] The assembly formed by the valve and the first spring constitutes a primary mass / spring system that tends to oscillate as gas passes through it. Advantageously, the assembly formed by the weight and the second spring creates a secondary mass / spring system that can also oscillate, but in opposite phase to the primary mass / spring system. This significantly reduces the overall movement of the check valve (excluding the main movements between the open and closed positions).

[0012] As a result, the non-return valve of the invention wears out less quickly.

[0013] The non-return valve of the invention is thus more reliable. Advantageously, the non-return valve is easier to manufacture.

[0014] Furthermore, it is possible to adapt existing check valves by hollowing out at least part of their control stem.

[0015] Furthermore, the invention prevents the check valve from wearing out too quickly, thus limiting the frequency of replacement. The invention therefore contributes to improving the performance of aircraft equipped with such a check valve and, in this respect, helps reduce the environmental impact of said aircraft. Optionally, the control rod is only partially hollowed out.

[0016] Optionally, the control rod extends longitudinally along the first axis, the housing extends coaxially to this first axis.

[0017] Optionally, the second spring is fixed at its first end to a face of the control rod which has as its normal the axis along which the control rod extends longitudinally.

[0018] Optionally, the check valve includes means for guiding the weight relative to the control rod.

[0019] Optionally, the check valve includes means for guiding the weight relative to the control rod in translation along a longitudinal axis of the control rod.

[0020] Optionally, the guiding means include at least one guide ring arranged inside the control rod and through which the weight moves relative to the control rod.

[0021] Optionally the weight and control rod are shaped to allow air lamination between the weight and control rod when the weight moves relative to the control rod.

[0022] The invention also relates to an aircraft gas distribution system comprising a valve as described above. Optionally, the distribution system is an inerting gas distribution system.

[0023] Other features and advantages of the invention will become apparent from the following description of a particular and non-limiting embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Reference will be made to the attached drawings, including: There figure 1 has already been introduced and schematically illustrates a prior art check valve. The figure 2 schematically represents a system for distributing an inerting gas in an aircraft according to a particular embodiment of the invention. figure 3 schematically illustrates a non-return valve of the system shown in the figure 2 the non-return valve being in the closed position. figure 4 schematically illustrates the valve shown in the figure 3 with the non-return valve in the open position. figure 5 schematically illustrates a variant of the non-return valve shown in the figure 3 . DETAILED DESCRIPTION OF THE INVENTION

[0025] There figure 2 illustrates a system 1 for generating a gas in an aircraft. System 1 is, for example, a system for generating an inerting gas.

[0026] System 1 is associated with at least one fuel tank of an aircraft to inject an inert gas such as, for example, a gas of or based on: nitrogen, carbon dioxide...

[0027] As is known per se, system 1 includes an inerting gas generator 2 comprising an oxygen-depleted air circuit to generate nitrogen-enriched inerting gas. For this purpose, system 1 includes air supply means 3 connected to at least one inlet 4 of the generator 2, the air being purge air diverted from at least one aircraft engine and / or air from a passenger cabin of the aircraft and / or air outside the aircraft. Furthermore, system 1 includes means 5 for distributing the inerting gas to the fuel tank(s), said means being connected to at least one outlet 7 of the generator 2.

[0028] Such a generator 2 is well known from prior art and will not be detailed here.

[0029] Furthermore, the distribution means 5 include at least one pipe 8 through which the inerting gas is intended to circulate. The pipe 8 is equipped with at least one non-return valve 6.

[0030] With reference to figures 3 et 4 , the non-return valve 6 includes a valve 9 equipped with a control rod 10 for the valve 9.

[0031] The control rod 10 extends straight along a first axis X. The control rod 10 is here shaped into a cylinder of revolution of height extending along the first axis X.

[0032] The valve 9 extends straight ahead coaxially with the control rod 10 along the first axis X.

[0033] Optionally, the check valve 6 is arranged in the pipe 8 so that the first axis X is parallel and optionally coincides with the straight axis A along which extends the portion of the pipe 8 in which the check valve 6 is arranged.

[0034] Valve 9 is arranged to slide along the first X axis between: a closed position where the valve 9 cooperates in operation with a seat 11 of system 1 (for example by resting on the seat 11) to close the line 8 and thus prevent fuel (especially in the form of vapors) from flowing back from the tank(s) to the generator 2 (as illustrated in the figure 3 ), and an open position where the valve 9 is offset from the seat 11 and allows the passage of inerting gas from the generator 2 to the fuel tank (as illustrated in the figure 4 ).

[0035] For example, seat 11 is a seat of the pipe 8 or seat 11 is a seat of a body 20 of the non-return valve 6.

[0036] In the latter case, the valve 9 is arranged in the body of the check valve 6 so as to slide along the first axis X between: the closed position where the valve 9 cooperates in service with the seat 11 of the body 20 (for example by resting on the seat 11), and an open position where the valve 9 is offset from the seat 11.

[0037] The control rod 10 is preferably associated with one or more translational guide elements of the control rod 10 (not shown here) and for example associated with one or more guide bearings and / or one or more guide rings.

[0038] This makes it easier for valve 9 to slide between the two positions mentioned above.

[0039] Furthermore, the check valve 6 includes a first spring 12 arranged outside the control rod 10. The first spring 12 extends so as to surround the control rod 10 by extending longitudinally along the first axis X. The first spring 12 is arranged so that its first end is connected to the valve 9 and its second end to the body 20 and / or to the pipe 8.

[0040] Typically the first end of the first spring 12 rests on the face of the valve 9 to which the control rod 10 is already attached. Typically the first end of the first spring 12 is attached to said face of the valve 9 to which the control rod 10 is already attached.

[0041] The first spring 12 is arranged to constrain the valve 9 to its closed position. Thus, the equilibrium position of the valve 9 is the closed position. Only the circulation of the inerting gas can temporarily oppose the action exerted by the first spring 12 on the valve 9, thereby moving it from its closed position to its open position.

[0042] It is noted that the first spring 12 has an influence on the pressure differential applied to the check valve 6 causing the opening of the valve 9 (i.e. its passage from the open position to the closed position) and / or has an influence on the flow of gas passing through the check valve 6 and therefore on the oscillations of the valve 9. We can thus choose the first spring 12 in particular to define at what pressure differential exerted on the valve 9 it should open.

[0043] Furthermore, the control rod 10 has at least one hollow portion. Typically, the control rod 10 has at least one hollow section.

[0044] Preferably, the control rod 10 is not hollow along its entire length (considered along the first X axis).

[0045] It is therefore understood that the control rod includes a solid portion 22. Typically the solid portion 22 is shaped in the form of a solid section.

[0046] The said solid portion 22 is shaped so that preferably the said solid portion 22 has a length (considered along the first axis X) which is significantly greater than the thickness (also along the first axis X) of at least the end face of the valve 9 bearing against the seat 11. For example, the control rod 10 is solid at least at its first end 14 of attachment to the valve 9 and is hollow at least at its second end 15 opposite to that of attachment to the valve 9.

[0047] The control rod 10 thus has a housing 13 opening at a second axial end 16 (along the first axis X) at the level of the second end 15 of the control rod 10 and blind at its first axial end 17 opposite its second axial end 16.

[0048] The non-return valve 6 also includes a weight 18 arranged in the housing 13 and preferably entirely arranged in the housing 13. The weight 18 is therefore invisible from outside the control rod 10. The weight 18 is for example formed in a block, such as a block of metallic material.

[0049] The non-return valve 6 also includes a second spring 19, which is also arranged in the housing 13 and preferably entirely within the housing 13. The second spring 19 is therefore invisible from outside the control rod 10. The second spring 19 is arranged so as to be integral with the weight 18 at one end and with the control rod 10 at the other. The second spring 19 thus also extends longitudinally along the first axis X.

[0050] It is therefore understood that the first spring 12 and the second spring 19 extend coaxially between each other and to the control rod 10 and to the first axis X.

[0051] More specifically here, the second spring 19 is fixed at its first end to the solid portion 22 of the control rod 10 and at its second end to the weight 18. Typically the second spring 19 is fixed at its first end to a face of the solid portion 22 having normal to the first axis X.

[0052] The weight 18 is optionally arranged in the check valve 6 further away from the valve 9 than the second spring 19.

[0053] We can thus conclude that the weight 18 is arranged in the extension (along the first X axis) of the valve 9. In particular, the valve 9 and the weight 18 extend coaxially with each other and with the first X axis.

[0054] It is also noted that the non-return valve 6 is such that the weight 18 is offset from an internal cylindrical wall of the housing of the control rod 10.

[0055] With reference to the figure 2 When the inerting gas forces the valve 9 open, the first assembly, consisting of the valve 9 and the first spring 12, can begin to oscillate. However, the second assembly, consisting of the weight 18 and the second spring 19, can also begin to oscillate, but in opposite phase to the first assembly, so as to partially or completely cancel the oscillations of the first assembly, and in particular those of the valve 9.

[0056] We note that the weight 18 oscillates mainly according to a translational movement along the first axis X.

[0057] In particular, the second assembly oscillates (at least predominantly) relative to the pipe 8 in the same axis (here the first X axis) as the valve 9 but in opposite phase with respect to it.

[0058] It is therefore understood that the reduction of oscillations in the check valve 6 is achieved by generating at least one mechanical force applied to the valve 9 by the second assembly. The inerting gas itself has little or no influence on the reduction of oscillations. Preferably, the second assembly is defined (for example, the stiffness of the second spring 19 and / or the mass of the weight 18) so that the force applied by the second spring 19 on the valve 9 is substantially the same as the force applied by the gas flow in the pipe 8 on the valve 9 (also called the excitation force).

[0059] Preferably, the second set (for example the stiffness of the second spring 19 and / or the mass of the weight 18) is defined so that the time constant characteristic of the oscillations of the second set is substantially identical to the time constant characteristic of the oscillations of the first set.

[0060] By "substantially identical" we mean "identical" to the other value or "as close as possible" to the other value. Preferably, by "substantially identical" we mean that a first value is identical to the second value within 5%.

[0061] It is therefore understood that the definition of the second assembly (in particular the stiffness of the second spring 19 and / or the mass of the weight 18) is directly linked to the characteristics of the first assembly (in particular the stiffness of the first spring 12 and / or the mass of the valve 9).

[0062] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0063] In particular, a greater number of check valves can be arranged in the pipe.

[0064] The check valve may have more springs and / or weights than specified. For example, the check valve may have two weight / spring assemblies arranged in series or parallel inside the control stem. Alternatively, the check valve may have another spring arranged similarly to the first spring to ensure redundancy. This second spring will have one end connected to the valve and the other to the pipe or the body of the check valve. The radial clearance between the weight and the inner wall of the control stem may differ from that described.For example, the radial clearance can be reduced so that the weight is guided in translation along the first X-axis by the inner wall. Alternatively, the weight and the inner wall can be configured to allow for airflow between them as the weight slides relative to the control rod. Typically, the weight can be externally shaped in the same way as the inner wall, resulting in a very thin and uniform gap between the weight and the inner wall.

[0065] Although here the weight / second spring assembly counteracts (at least partially) the oscillations of the valve / first spring assembly, the weight / second spring assembly can also be shaped to dampen at least one movement of the weight / second spring assembly. As indicated above, the check valve can thus be shaped to ensure a compression of the air circulating between the valve and the inner wall. The valve can also include means for guiding the weight within the control rod. figure 5This illustrates a variant of the invention in which the weight 18 is associated with guiding means 21 for the weight 18 within the control rod 10. The guiding means may be a specific fit between the weight and the control rod as described above (allowing, for example, air compression) and / or may include at least one mechanical guiding element within which the weight moves, such as a bearing or a bushing. This would limit the risk of influencing the cracking pressure value of the check valve.

[0066] The check valve will be shaped so that, preferably, the weight moves as much as possible in a translational motion along the first X-axis, just like the valve. Preferably, the guiding means will be shaped to allow only translation of the weight inside the control rod along the first X-axis.

[0067] Although here the check valve is arranged in the pipe so that the first axis X is parallel to and coincides with axis A, the check valve can be arranged differently in the pipe and for example: so that the first X axis is parallel but not coincident with the A axis, so that the first X axis is inclined with respect to the A axis.

[0068] Within a single check valve, a different number of springs than specified may be present. The weight may be positioned in the check valve closer to the valve than the second spring. Although here the gas distribution system is a system for distributing an inerting gas associated with at least one aircraft tank, the invention is applicable to many other applications. The gas distribution system could thus be an aircraft oxygen supply system, an aircraft ventilation system, a system for pressurizing at least one aircraft fuel tank, etc.

Claims

1. A gas distribution system of an aircraft comprising a check valve, the valve comprising a valve body (9) provided with a control rod (10) of the valve body, the valve being intended to slide along a first axis (X) between a closed position in which the valve engages in use with a seat (11) of the distribution system and an open position in which the valve body is moved away from the seat, the valve comprising at least one first spring (12) arranged outside the control rod and tending in use to hold the valve body against the seat, the valve comprising an assembly comprising at least one weight (18) and at least one second spring (19) which are arranged at least partially inside the control rod, the second spring being connected at a first of its two ends to the control rod and at a second of its two ends to the weight, a housing (13) being provided in the control rod (10) so as to open at a first axial end at a first end of the control rod, opposite to that connected to the valve body, and so as to be blind at a second axial end opposite to the first axial end.

2. The system according to Claim 1, wherein the control rod (10) is only partially hollowed out.

3. The system according to Claim 1 or Claim 2, wherein the control rod (10) extends longitudinally along the first axis (X), the housing (13) extends coaxially to the first axis.

4. The system according to any one of Claims 1 to 3, wherein the second spring (19) is fixed at its first end to one side of the control rod (10), the side whose normal is the axis along which the control rod extends longitudinally.

5. The system according to any one of the preceding claims, comprising means of guiding (21) the weight (18) relative to the control rod (10).

6. The system according to Claim 5, wherein the guiding means comprise at least one guiding ring arranged within the control rod (10) and through which the weight (18) moves relative to the control rod.

7. The system according to any one of the preceding claims, wherein the weight (18) and the control rod (10) are shaped to allow laminar air flow between the weight and the control rod when the weight moves relative to the control rod.

8. The system according to any one of the preceding claims, wherein the distribution system is a system for distributing inerting gas.