Inert Gas Generation System, And An Aircraft Fuel Tank Inerting System Implementing Said Inert Gas Generation System

Abstract

An inert gas generation system from a flow of air, notably for an inerting system for at least one aircraft fuel tank. The generation system includes an air circuit having an air inlet, an inert gas outlet, and a first and a second air separation module arranged in series on the air circuit to deplete oxygen within the air and to generate a nitrogen-enriched inert gas.

Claims

1. An inert gas generation system from a flow of air, for an inerting system for at least one aircraft fuel tank, said generation system comprising an air circuit comprising an air inlet, an inert gas outlet, and a first and a second air separation module arranged in series on said air circuit to deplete oxygen within the air and to generate a nitrogen-enriched inert gas.

2. The generation system according to claim 1, characterized in that the air circuit comprises routing means for a portion of the air flow upstream of the first module directly to the second module, and routing means for the entire air flow downstream from the first module directly to the inert gas outlet.

3. The generation system according to claim 2, characterized in that the generation system further comprises a first valve and a second valve arranged on the air circuit between the first module and the second module, the first valve being connected to the gas outlet by a first bypass circuit, and the second valve being connected to the air circuit upstream of the first module by a second bypass circuit.

4. The generation system according to claim 3, characterized in that the valves are flow control valves.

5. The generation system according to claim 3, characterized in that the valves are pressure control valves.

6. The generation system according to claim 1, characterized in that the first and second air separation module comprise zeolite membranes.

7. The generation system according to claim 6, characterized in that the size of the zeolite membranes of the first module is different from the size of the zeolite membranes of the second module.

8. An inerting system for at least one aircraft fuel tank, said system comprising at least one inert gas generating system supplied with bleed air diverted from at least one engine, air from a passenger cabin, or both air diverted from at least one engine and air from the passenger cabin and distribution means for the inert gas to at least one fuel tank connected to the inert gas generation system, said inerting system being characterized in that the inert gas generation system complies with claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further advantages and features will become clearer from the following description, given by way of a non-limiting example, of the inert gas generation system according to the invention, with reference to the accompanying drawings in which:

[0027] FIG. 1 is a schematic view of an inert gas generation system according to the invention;

[0028] FIG. 2 is a schematic view showing an inerting system according to the invention;

[0029] FIG. 3 is a schematic view similar to that of FIG. 1, showing the series arrangement of the air separation modules;

[0030] FIG. 4 is a schematic view similar to that of FIG. 1, showing the parallel arrangement of the air separation modules.

DETAILED DESCRIPTION OF THE INVENTION

[0031] In reference to FIG. 1, the invention relates to an inert gas generation system (1) comprising an air circuit (2) to deplete oxygen in order to generate a nitrogen-enriched inert gas.

[0032] In reference to FIG. 2, the generation system (1) is notably intended to be used in an inerting system (11) for at least one aircraft fuel tank (12). To this end, the inert gas generation system (1) comprises an air inlet (3) supplied with bleed air diverted from at least one engine and/or air from a passenger cabin and/or air from outside the aircraft via an air preparation system (14) that uses a compressor, and an inert gas outlet (4) connected to distribution means (13) for the inert gas to the fuel tank(s) (12). The generation system (1) also comprises an oxygen-enriched gas outlet (15).

[0033] The inerting system (11) allows an inert gas to be generated and introduced into said aircraft fuel tank(s) (12) for safety reasons in order to reduce the risk of explosion from said tanks. The injected inert gas aims to render the fuel tank(s) (12) inert, i.e., allows the level of oxygen present within said tank(s) to be reduced, and notably to maintain this level below a certain threshold, preferably less than 12%.

[0034] In reference to FIG. 1, the inert gas generation system (1) comprises at least two air separation modules (5, 6), comprising for example zeolite membranes through which the air is forced such as to obtain an inert gas with a high nitrogen content and an inert gas with a high oxygen content.

[0035] According to the invention, the air circuit (2) of the inert gas generation system (1) allows the two air separation modules (5, 6) to be connected together, and comprises arrangements for selectively routing, upstream of the first module (5), a portion of the air flow directly to the inlet of the second module (6), and arrangements for selectively routing, downstream from the first module (5), the entire air flow directly to the inert gas outlet (4).

[0036] To this end, the air circuit (2) comprises two valves (7, 8) arranged between the first and second air separation module (5, 6). A first valve (7) is connected directly to the gas outlet (4) via a first bypass circuit (9), and a second valve (8) is connected to the air circuit (2) upstream of the first air separation module (5) via a second bypass circuit (10).

[0037] The invention therefore allows the arrangement of the air separation modules (5, 6) to change from series to parallel.

[0038] When the aircraft fuel tanks require a high inert gas flow rate, notably during a non-stable phase of the aircraft such as the descent phase, the air separation modules (5, 6) are changed to a series arrangement by the actuation of the valves (7, 8) in order to obtain a high inert gas flow rate while ensuring that said inert gas is of a high quality and has a low oxygen content of about 3%.

[0039] To this end, and in reference to FIG. 3, the valves (7, 8) are switched from a series control position wherein the air flow circulating within the air circuit (2) crosses the first air separation module (5), passes through the first and second valve (7, 8), crosses the second air separation module (6), and is discharged through the inert gas outlet (4) to be distributed and injected into the tanks.

[0040] The series arrangement of the air separation modules (5, 6) is also possible during the cruising phase of the aircraft in order to allow the sizing of the filtration components of the inert gas generation system (1) to be optimized.

[0041] Alternatively, when the tanks require a low inert gas flow rate and depending on the need or the flight phase, the air separation modules (5, 6) are changed to a parallel arrangement by the actuation of the two valves (7, 8).

[0042] To this end, and in reference to FIG. 4, the valves (7, 8) are switched to a parallel control position therein from the air inlet (3): [0043] a first portion of the air flow circulating in the air circuit (2) crosses the first air separation module (5) to the first valve (7) which then routes the first portion of the air flow in the first bypass circuit (9) and directly to the inert gas outlet (4) without passing through the second separation module (6); [0044] a second portion of the air flow is routed by the second valve (8) in the second bypass circuit (10) and directly to the inlet of the second separation module (6), without passing through the first separation module (5), and crosses said second module (6) to the inert gas outlet (4).

[0045] According to the invention, inert gases with similar purities may be obtained with different flow rates depending on the arrangement in series or in parallel of the air separation modules (5, 6). This is particularly advantageous when the generation of an inert gas with constant quality and purity, and with different flow rates is required.

[0046] The invention is particularly advantageous when the valves (7, 8) used are pressure control or flow control valves.

[0047] Of course, without departing from the scope of the invention, other embodiments are possible with a generation system (1) comprising more than two air separation modules (5, 6) in order to generate an inert gas with a purity that meets the needs, notably for example in the context of closed loop control applications. The key aspects of the invention are the provision of an inert gas generation system (1) with air separation modules (5, 6) arranged in series, and the ability to advantageously change, as needed, said air separation modules (5, 6) to a parallel arrangement. Alternatively, with more than two air separation modules (5, 6), other possible arrangements are: an arrangement with air separation modules (5, 6) in series and in parallel, and an arrangement with air separation modules (5, 6) in series only. In addition, and to better adjust to the quantity and quality requirements of the inert gas, the size of the zeolite membranes of the first module (5) may differ from the size of those of the second module (6).

[0048] The inert gas generation system (1) according to the invention may also be used at the output (15) of a generation system (1) for extracting the residual nitrogen in said oxygen-enriched gas and improving the yield of said system.

[0049] Similarly, since an inert gas generation system (1) also generates an oxygen-enriched gas, the invention may be used to generate an oxygen-enriched gas with air separation modules selectively arranged in series or in parallel.