Check valve for aircraft gas distribution system and corresponding system

Abstract

The invention relates to a check valve for an aircraft gas distribution system, comprising a valve part (9) provided with a lever (10) for the valve part, intended to slide along a first axis (X) between a closed position, in which the valve part is in use engaged with a seat (11) of the distribution system, and an open position, in which the valve part is in use engaged with the seat (11) of the distribution system. The valve member moves away from the seat, the valve comprising a first spring (12) arranged outside the control rod and tending in use to retain the valve member against the seat, the valve comprising an assembly comprising at least one counterweight (18) and a second spring (19) arranged at least partially inside the control rod, the spring is connected at a first end of both ends thereof to the lever, and at a second end of both ends thereof to the weight portion. The invention also relates to a corresponding system.

Description

Technical Field

[0001] The invention relates to a non-return valve intended to be arranged in a gas distribution system of an aircraft, such as an airplane, a helicopter.

[0002] The invention also relates to a gas distribution system for an aircraft comprising such a non-return valve. Background Art

[0003] In aircraft, for safety reasons, it is known to associate an inert gas distribution system with one or more fuel tanks of the aircraft. An inert gas distribution system, also called an inert system, thereby produces an inert gas (nitrogen, carbon dioxide, etc.) which is then injected into the tank(s) to reduce the risk of explosion.

[0004] The inert system comprises at least one pipe running between the gas generator of said system and the tank(s) intended for the circulation of the inertizing gas. Such pipe is usually equipped with a non-return valve 106, as shown in FIG1 . Such non-return valve 106 thus comprises a valve body 109 provided with a control rod 110, the valve body 109 sliding between the following positions:

[0005] a closed position in which the valve body 109 rests on the seat 111 of the body of the non-return valve 106 ; and

[0006] An open position in which the valve body 109 is moved away from the seat 111 .

[0007] The spring 112 is also arranged with its first end connected to the valve body 109 and its second end connected to the body of the check valve 106 to hold the valve body 109 in the closed position.

[0008] The non-return valve 109 thus allows the inert gas to pass through the tank, but limits the risk of fuel in vapor form rising from the tank to the gas generator.

[0009] Unfortunately, the inert gas passing through the check valve 109 tends to create oscillations within the check valve 109, so the check valve 109 wears rapidly, requiring periodic replacement for obvious safety reasons.

[0010] According to another aspect, climate change has proven to be a major concern for many legislative and regulatory bodies around the world. In fact, countries have, are or will adopt a wide range of carbon emission restrictions. Specifically, an ambitious standard applies both to new aircraft and to aircraft in use that need to implement technical solutions to comply with existing regulations. For several years, civil aviation has been contributing to the fight against climate change.

[0011] Technological research has led to significant improvements in the environmental performance of aircraft. Applicants must consider the influencing factors at all stages of design and development in order to obtain more energy-efficient and environmentally friendly aviation components and products, whose integration and use in civil aviation have moderate environmental consequences, thereby improving the energy efficiency of aircraft.

[0012] Therefore, the Applicant has been working to reduce the environmental footprint of its activities by using benign methods and manufacturing processes to reduce its negative impact on the climate and to minimize greenhouse gas emissions. Summary of the invention

[0013] One of the objects of the present invention is therefore to provide a non-return valve for an aircraft gas distribution system which wears slowly.

[0014] To this end, a non-return valve is provided for an aircraft gas distribution system, the non-return valve comprising a valve body provided with a valve body control rod, the valve body being intended to slide along a first axis between a closed position, in which the valve body engages with a seat of the distribution system in use, and an open position, in which the valve body moves away from the seat, the non-return valve comprising at least one first spring, which is arranged on the outside of the control rod and which tends to hold the valve member against the seat in use.

[0015] According to the present invention, the check valve includes an assembly consisting of at least one counterweight and at least one second spring, the counterweight and the second spring being at least partially arranged inside the control rod, the spring being connected to the control rod at a first end of its two ends and to the counterweight at a second end of its two ends.

[0016] The whole formed by the valve body and the first spring forms a first mass / spring system which tends to oscillate when gas passes through it. Advantageously, the assembly formed by the weight and the second spring forms a second mass / spring system which is also able to oscillate, but in antiphase with the first mass / spring system, thus significantly reducing the overall movement of the check valve (excluding the main movement between the open and closed positions).

[0017] As a result, the check valve of the present invention wears less quickly.

[0018] This makes the check valve of the present invention more reliable.

[0019] Advantageously, the check valve is easy to manufacture.

[0020] Additionally, existing check valves may be retrofitted by at least partially hollowing out their control stems.

[0021] Furthermore, the invention prevents the non-return valve from wearing too quickly, which limits the frequency of its replacement. The invention thus contributes to improving the performance of an aircraft equipped with such a non-return valve and, in this sense, to reducing the environmental impact of said aircraft.

[0022] Optionally, the control rod is only partially hollowed out.

[0023] Optionally, the housing is arranged in the control rod so as to be open at a first axial end opposite to the end connected to the valve body at a first end of the control rod and to be blind at a second axial end opposite to the first axial end.

[0024] Optionally, the control rod extends longitudinally along a first axis and the housing extends coaxially with the first axis.

[0025] Optionally, the second spring is fixed at its first end to a side of the control rod, the normal of which is the axis of the control rod along its longitudinal extension.

[0026] Optionally, the non-return valve comprises means for guiding the weight relative to the control rod.

[0027] Optionally, the non-return valve comprises means for guiding the weight in translation relative to the control rod along the longitudinal axis of the control rod.

[0028] Optionally, the guide means comprises at least one guide ring arranged inside the control rod and through which the weight moves relative to the control rod.

[0029] Optionally, the counterweight and the control rod are shaped to allow laminar flow between the counterweight and the control rod when the counterweight moves relative to the control rod.

[0030] The present invention also relates to a gas distribution system of an aircraft comprising the above-mentioned check valve.

[0031] Alternatively, the distribution system may be an inert gas distribution system.

[0032] Other characteristics and advantages of the invention will emerge on reading the following description of particular and non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Reference will be made to the accompanying drawings, in which:

[0034] FIG. 1 is as described above and is a schematic diagram showing a check valve of the related art.

[0035] Figure 2 Schematic diagram showing an inert gas distribution system in an aircraft according to a specific embodiment of the present invention.

[0036] Figure 3 yes Figure 2Schematic diagram of the check valve of the system shown, with the check valve in a closed position.

[0037] Figure 4 yes Figure 3 Schematic diagram of the valve shown with the check valve in the open position.

[0038] Figure 5 yes Figure 3 Schematic diagram of a variant of the check valve shown. DETAILED DESCRIPTION

[0039] Figure 2 A gas generating system 1 in an aircraft is shown. The system 1 is, for example, a system for generating an inert gas.

[0040] The system 1 is associated with at least one fuel tank of an aircraft in order to inject an inert gas, such as nitrogen, carbon dioxide or a gas based on nitrogen or carbon dioxide.

[0041] In a manner known per se, the system 1 comprises an inert gas generator 2 consisting of an oxygen-depleted air circuit to produce nitrogen-rich inert gas.

[0042] To this end, the system 1 comprises air supply means 3 connected to at least one inlet 4 of the generator 2, the air being bleed air diverted from at least one engine of the aircraft and / or air in the cabin of the aircraft and / or air outside the aircraft. Furthermore, the system 1 comprises means 5 for distributing inert gas into the fuel tank(s), said means being connected to at least one outlet 7 of the generator 2.

[0043] Such generators are well known in the art and will not be described in detail in this case.

[0044] Furthermore, the distribution device 5 comprises at least one duct 8 through which the inert gas is intended to circulate. The duct 8 is equipped with at least one non-return valve 6.

[0045] refer to Figure 3 and Figure 4 The check valve 6 comprises a valve body 9 which is provided with a control rod 10 for the valve body.

[0046] The control rod 10 extends linearly along the first X-axis. In this example, the control rod 10 is shaped as a highly revolved cylinder extending along the first X-axis.

[0047] The valve body 9 extends linearly along the first X-axis line coaxially with the control rod 10 .

[0048] Optionally, the check valve 6 is arranged in the pipe 8 so that the first X axis is parallel to the straight A axis and optionally coincides with the straight A axis along which the portion of the pipe 8 where the check valve 7 is located is located.

[0049] The valve body 9 is arranged so that it slides along the first X-axis between the following two positions:

[0050] a closed position in which the valve body 9, in use, engages with the seat 11 of the system 1 (e.g. by resting on the seat 11) to close the conduit 8, thereby preventing the fuel (including vapour) from flowing from the tank(s) back to the generator 2 (e.g. Figure 3 shown); and

[0051] - an open position in which the valve body 9 moves away from the seat 11 and allows the inert gas to flow from the generator 2 to the fuel tank (eg Figure 4 shown).

[0052] For example, the seat 11 is a seat of the pipe 8 , or the seat 11 is a seat of the valve body 20 of the check valve 6 .

[0053] In the latter case, the valve body 9 is arranged in the valve body of the non-return valve 6 so as to slide along the first X-axis between the following two positions:

[0054] a closed position in which the valve body 9 engages, in use, with the seat 11 of the body 20 (eg by resting on the seat 11 ); and

[0055] An open position in which the valve body 9 is moved away from the seat 11 .

[0056] The control rod 10 is preferably combined with one or more guide elements for the translational movement of the control rod 10 (not shown here), and for example with one or more guide bearings and / or one or more guide rings.

[0057] This enables the valve body 9 to slide more easily between the two positions as described above.

[0058] Furthermore, the check valve 6 comprises a first spring 12 arranged outside the control rod 10. Thus, the first spring 12 extends in a manner surrounding the control rod 10 extending longitudinally along the first X axis. The first spring 12 is arranged such that its first end is connected to the valve body 9 and its second end is connected to the valve body 20 and / or the pipeline.

[0059] Typically, the first end of the first spring 12 rests on the side of the valve body 9 to which the control rod 10 has been fixed. Typically, the first end of the first spring 12 is fixed to the side of the valve body 9 to which the control rod 10 has been fixed.

[0060] The first spring 12 is arranged to constrain the valve body 9 in its closed position. Therefore, the equilibrium position of the valve body 9 is the closed position. Therefore, only the circulation of the inert gas can temporarily resist the action exerted by the first spring 12 on the valve body 9, causing it to move from the closed position to the open position.

[0061] It should be noted that the first spring 12 has an influence on the pressure difference applied to the non-return valve 6, causing the valve body 9 to open (i.e., it travels from the open position to the closed position) and / or has an influence on the gas flow through the non-return valve 6 and thus on the oscillation of the valve body 9. Therefore, the first spring 12 can be selected, in particular, to define the pressure difference applied to the valve body 9, under which the valve body should open.

[0062] Furthermore, the control rod 10 comprises at least one hollow portion. Typically, the control rod 10 comprises at least one hollow section.

[0063] Preferably, the control rod 10 is not hollow along its entire length (considered along the first X-axis).

[0064] It will therefore be appreciated that the control rod comprises a solid portion 22. Typically, the solid portion 22 is shaped in the form of a solid cross section.

[0065] The solid portion 22 is preferably shaped such that its length (considered along the first X axis) is significantly greater than the thickness (also along the first X axis) of at least the end side of the valve body 9 that rests against the seat 11. For example, the control rod 10 is solid at least at its first end 14 attached to the valve body 9 and is hollow at least at its second end 15 opposite to the first end attached to the valve body 8.

[0066] The control rod 10 thus has a housing 13 which opens at a second end 15 of the control rod 10 to a second axial end 16 (according to the first X-axis) and is dead at a first axial end 17 thereof opposite the second axial end 16 .

[0067] The non-return valve 6 further comprises a weight 18 arranged in the housing 13 and preferably completely arranged in the housing 13. The weight 18 is therefore not visible from the outside of the control rod 10. For example, the weight 18 is shaped as a block, such as a block made of metal.

[0068] The check valve 6 further comprises a second spring 19 which is also arranged in the housing 13 and preferably completely arranged in the housing. Therefore, the second spring 19 is not visible from the outside of the control rod 10. In this case, the second spring 19 is arranged to be fixed to the counterweight 18 at one end and to the control rod 10 at a second end. Therefore, the second spring 19 also extends longitudinally along the first X-axis.

[0069] It will therefore be appreciated that the first spring 12 and the second spring 19 extend coaxially with each other, with the control rod 10 and with the first X-axis.

[0070] More precisely, 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 counterweight 18. Typically, the second spring 19 is fixed at its first end to the side of the solid portion 22 that has the first X-axis as its normal.

[0071] The weight 18 may optionally be arranged in the check valve 6 further away from the valve body 9 than the second spring 19 .

[0072] Therefore, it should be noted that the weight 18 is arranged in the extension (along the first X-axis) of the valve body 9. Specifically, the valve body 9 and the weight 18 extend coaxially with each other and extend to the first X-axis.

[0073] It should also be noted that the check valve 6 is designed so that the weight portion 18 moves away from the cylindrical inner wall of the control rod housing 10 .

[0074] refer to Figure 2 When the inert gas forces the valve body 9 to open, the first assembly formed by the valve body 9 and the first spring 12 will oscillate. However, the second assembly formed by the weight 18 and the second spring 19 will also oscillate, but in antiphase with the first assembly to partially or completely offset the oscillation of the first assembly, especially the oscillation of the valve body 9.

[0075] It should be noted that the counterweight 18 oscillates primarily in a translational motion along the first X-axis.

[0076] Specifically, the second component oscillates (at least mostly) relative to the conduit 8 on the same axis as the valve body 9 (in this case the first X-axis), but in opposite phase to the valve body 9 .

[0077] It will therefore be appreciated that the oscillations 6 in the check valve may be reduced by at least one mechanical force generated by the second component and applied to the valve body 9. The inert gas itself may have little or no effect on the reduction of the oscillations.

[0078] Preferably, the second component (e.g., the stiffness of the second spring 19 and / or the mass of the counterweight 18) is defined so that the force exerted by the second spring 19 on the valve body 9 is substantially the same as the force exerted by the gas flow in the pipeline 8 on the valve body 9 (also called the excitation force).

[0079] Preferably, the second component (eg, the stiffness of the second spring 19 and / or the mass of the weight 18) is defined such that the time constant characteristic of the oscillation of the second component is substantially the same as the time constant characteristic of the oscillation of the first component.

[0080] The term "substantially the same" means "the same" or "as close as possible" to another value. Preferably, "substantially the same" means that the first value is the same as the second value, with a difference of more or less 5%.

[0081] Therefore, it can be understood that the definition of the second component (particularly the stiffness of the second spring 19 and / or the mass of the counterweight 18) is directly related to the characteristics of the first component (particularly the stiffness of the first spring 12 or the mass of the valve body 9).

[0082] Of course, the invention is not limited to the embodiments described but covers any variant included within the scope of the invention as defined by the claims.

[0083] Specifically, more check valves may be arranged in the pipeline.

[0084] The component may include a greater number of springs and / or counterweights than described above. For example, the check valve may include two counterweight / spring assemblies arranged in series or in parallel inside the control rod. For example, the check valve may include another spring arranged in a similar manner to the first spring to ensure redundancy. Therefore, the other spring will include a first end connected to the valve body and a second end connected to the pipeline or valve body of the check valve. For example, the check valve may include an additional spring arranged in a similar manner to the second spring to ensure redundancy. Therefore, the additional spring will include a first end connected to the valve body and a second end connected to the valve body.

[0085] The radial clearance between the counterweight and the inner wall of the control rod may be different from that described. For example, the radial clearance may be lower so that the counterweight is guided by the inner wall in translation along the first X-axis. For example, the counterweight and the inner wall may be configured so that laminar flow between each other is allowed when the counterweight slides relative to the control rod. Typically, the counterweight may be shaped outwardly in the same manner as the inner wall so that the space between the counterweight and the inner wall is very thin and regular.

[0086] Although in the present case the weight / second spring assembly makes it possible to (at least partially) counteract the oscillations of the valve / first spring assembly, the weight / second spring assembly can also be shaped so as to also ensure damping of at least one movement of the weight / second spring assembly. As described above, the non-return valve can thus be shaped so as to ensure a laminar flow between the valve and the inner wall. The valve can also comprise means for guiding the weight in the control rod. Thus, Figure 5 A variant of the invention is shown in which the weight 18 is combined with a guide 21 of the weight 18 in the control rod 10. The guide may be a specific adjustment between the weight and the control rod as described above (e.g. to allow laminar flow) and / or may comprise at least one mechanical guide element such as a bearing or a ring in which the weight moves. This will limit the risk of influencing the check valve rupture pressure value.

[0087] Therefore, the non-return valve will be shaped to preferably allow the weight to translate as much as possible along the first X-axis, just like the valve body.Preferably, the guide means should be shaped to only allow the weight inside the control rod to translate along the first X-axis.

[0088] Although in this example the check valve is arranged in the pipeline so that the first X axis is parallel and coincident with the A axis, the arrangement of the check valve in the pipeline may be different, for example:

[0089] - making the first X axis parallel to the A axis but not coincident with the A axis;

[0090] - making the first X-axis inclined relative to the A-axis.

[0091] In the same check valve there may be a different number of springs than indicated.The weight may be arranged in the check valve closer to the valve body than the second spring.

[0092] Although in this example the gas distribution system is a system for dispensing an inert gas in conjunction with at least one tank of an aircraft, the invention is applicable to many other applications.

[0093] Thus, the gas distribution system may be an aircraft oxygen supply system, an aircraft ventilation system, a pressurization system for at least one aircraft fuel tank or the like.

Claims

1. A gas distribution system for an aircraft, comprising a non-return 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 moves 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) 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 arranged in the control rod (10) so as to be open at a first axial end of the control rod opposite to the end connected to the valve body and to be outlet-free at a second axial end opposite to the first axial end.

2. The system according to claim 1, characterized in that The control rod (10) is only partially hollowed out.

3. The system according to claim 1 or 2, characterized in that: The control rod (10) extends longitudinally along the first axis (X), and the housing (13) extends coaxially with the first axis.

4. The system according to any one of claims 1 to 3, characterized in that The second spring (19) is fixed at its first end to a side of the control rod (10), the normal of which is the axis of the control rod along which it extends longitudinally.

5. System according to any one of the preceding claims, characterized in that It comprises means (21) for guiding the counterweight (18) relative to the control rod (10).

6. The system according to claim 5, characterized in that The guide means comprise at least one guide ring arranged inside the control rod (10) and through which the weight (18) moves relative to the control rod.

7. A system according to any one of the preceding claims, characterised in that The counterweight (18) and the control rod (10) are shaped to allow laminar flow between the counterweight and the control rod when the counterweight moves relative to the control rod.

8. System according to any one of the preceding claims, characterized in that The distribution system is a system for distributing an inert gas.

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