GB2533585A

GB2533585A - Gas separation module, cartridge for use therein, aircraft compartment inerting system and method of maintaining an aircraft compartment inerting system

Info

Publication number: GB2533585A
Application number: GB1422947.0A
Authority: GB
Inventors: Smiles Mark; Family Oliver
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2014-12-22
Filing date: 2014-12-22
Publication date: 2016-06-29

Abstract

An aircraft compartment inerting system comprises a gas separation module 1 arranged to receive a flow of oxygen-containing gas and one or more conduits for delivering oxygen-depleted gas to at least one compartment. The gas separation module comprises an air inlet 2 for the introduction of an oxygen-containing gas flow, and a first outlet 3 for the egress of a gas flow depleted in oxygen. The module further comprises a module housing 4 and a removable cartridge 5 located within the housing. The cartridge is located in a gas flow path between the inlet and the first outlet, and comprises a gas separating material 6 for depleting the amount of oxygen in the gas flow. The system may further comprise a second outlet 7 for the egress of a gas with an enriched oxygen content. The inlet and the first outlet may be coaxially arranged and at opposing ends of the module housing which may be elongate. The cartridge may be elongate and prismatic, comprise a casing 8 permeable to oxygen-enriched gas, and define an annular space 32 within the module housing for the receipt of oxygen-enriched gas.

Description

GAS SEPARATION MODULE, CARTRIDGE FOR USE THEREIN, AIRCRAFT

COMPARTMENT INERTING SYSTEM AND METHOD OF MAINTAINING AN

AIRCRAFT COMPARTMENT INERTING SYSTEM

BACKGROUND OF THE INVENTION

[0001] The present invention concerns gas separation modules and their use. More particularly, but not exclusively, this invention relates to a gas separation module. The invention also concerns a cartridge for use in a gas separation module, an aircraft compartment inerting system and a method of maintaining an aircraft compartment inerting system.

[0002] Fuel tank inerting systems are well-known to those skilled in the art. Fuel tanks are supplied with an inerting gas (such as oxygen-depleted air) in order to reduce the chance of an explosion occurring in the fuel tank. A gas comprising oxygen (typically air taken from an engine bleed and then cooled) is passed through a gas separating material which removes at least some of the oxygen from the gas stream. Modules comprising such gas separating materials (SmartFluxx® and HiFLuxxg) are available from Parker Filtration & Separation BV, Etten-Leur, Netherlands. The oxygen-depleted gas stream is then fed to a fuel tank. Similar gas separation modules are also used to provide gas with increased oxygen content. Such modules are often used to supply oxygen-enhanced air to patients, for example. The gas separating material in such modules removed nitrogen from inlet air, thereby providing an outlet gas with an enhanced oxygen content.

[0003] Such modules have finite lifetimes because the material used to remove oxygen has a finite lifetime. Once such modules have come to the end of their lives, they are sent back to the supplier for the membrane material to be regenerated, recycled or discarded. This is expensive because the modules are large and heavy and replacement of the entire module may be time-consuming.

100041 The present invention seeks to mitigate one or more of the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved gas separation module.

SUMMARY OF THE INVENTION

100051 In accordance with a first aspect of the present invention, there is provided a gas separation module for producing a flow of oxygen-depleted or oxygen-enhanced gas, the module comprising: an inlet for the introduction of a gas flow comprising at least two components, one of which is oxygen; a first outlet for the egress of a gas flow depleted or enhanced in oxygen; a module housing; and a removable cartridge located within the module housing and located in a gas flow path between the inlet and the first outlet, said cartridge comprising a gas separating material for depleting or enhancing the amount of oxygen in the gas flow.

[0006] The word "cartridge" indicates that the cartridge is typically self-contained. The word "removable" indicates that the cartridge may be readily removed. The cartridge may be single-use, or may be regenerated, for example, by heating the cartridge. The cartridge is typically replaceable i.e. one cartridge would be removed and a similar cartridge inserted. The cartridge may be removed by a suitably-qualified technician without causing damage to the rest of the module.

100071 If the gas separation module is for use on an aircraft, particularly for supplying an inerting gas, then the gas separating material is optionally for depleting the oxygen in the gas flow.

[0008] Alternatively, the gas separating material may be for enhancing the oxygen content of the gas flow, in which case the gas separation module may be for use in a medical environment.

100091 The module may comprise a second outlet for the egress of a gas with an enhanced or depleted oxygen content. If the first outlet is for the egress of gas depleted in oxygen, then the second outlet is for the egress of gas enhanced in oxygen and vice versa.

100101 Those skilled in the art will realise that "depleted" indicates that a reduced oxygen content compared to the inlet gas, not that all oxygen is removed. Typically, oxygen content of the gas stream will be reduced to a non-zero value (such as 4-12% by volume) because it is unnecessary to reduce oxygen content to zero in order to obtain a satisfactory inerting effect. Furthermore, reducing oxygen content to zero may be expensive and may reduce the lifetime of the cartridge.

[0011] The module is typically elongate. The inlet is typically located at or near a first end of the module. Likewise, the first outlet is typically located at or near a second end of the module remote from the first end. The inlet and the first outlet may be coaxially arranged. The second outlet, if present, is optionally located between the inlet and the first outlet.

100121 The module housing optionally comprises one or more of the inlet, the first outlet and the second outlet. The module housing may optionally be elongate. The inlet may therefore be provided at or near a first end of the module housing. The first outlet may be provided at or near a second end of the module housing remote from the first end. [0013] The module housing may comprise a central portion, an inlet cap provided at the first end of the module housing and an outlet cap provided at the second end of the module housing. The inlet cap may be provided with the inlet and the outlet cap may be provided with the first outlet. The central portion of the module housing may be provided with the second outlet, if present. The central portion is typically generally prismatic in shape (i.e. has the same cross-sectional shape and area along its length), optionally generally cylindrical in shape. At least one (and optionally each) of the inlet cap and the outlet cap is removably attachable to the central portion of the module housing. At least one (and optionally each) of the inlet cap and the outlet cap is provided with a configuration (such as a screw thread or a bayonet fitting) for removable attachment to a corresponding configuration provided on the central portion of the module housing. Therefore, the module housing central portion is optionally provided with configurations (such as a screw thread or bayonet fitting) which enable the removable attachment of the inlet cap and the outlet cap. Such configurations are typically located at or near respective ends of the module housing central portion.

100141 The cartridge is optionally located substantially within the module housing central portion. The cartridge and module housing define a space therebetween for the receipt of oxygen-enhanced or oxygen-depleted gas from the cartridge. The space is optionally annular. The space is optionally in fluid communication with the second outlet, thereby permitting egress of oxygen-enhanced or oxygen-depleted gas through the second outlet. The module may be provided with a movement inhibitor which inhibits movement of the cartridge. For example, the module may be provided with an end-stop which inhibits movement of the cartridge past a certain point within the module. This may help position the cartridge within the module and may help inhibit unwanted over-movement of the cartridge. The module housing central portion or the outlet cap may be provided with a movement inhibitor.

100151 One or both of the inlet cap and the outlet cap optionally define a gas-containing volume between the cartridge and the respective inlet and first outlet. The inlet cap and/or the outlet cap may comprise a skirt portion and a dome portion, the dome portion being provided with the respective inlet or first outlet. The skirt is typically provided with a configuration for removable attachment to a corresponding configuration provided on the central portion of the module housing.

[0016] At least one seal is optionally provided between the cartridge and the module housing. Typically two seals are provided between the module housing and the cartridge. Such seals seek to isolate the inlet, first outlet and second outlet from one another so that inlet gas cannot pass to the first and second outlets without passing through the cartridge. Therefore, a first seal is optionally provided at or near a first end of the cartridge and a second seal is optionally provided at or near a second end of the cartridge. The first and second seals are optionally attached to the cartridge.

[0017] The cartridge is typically elongate and is typically prismatic (i.e. has the same cross-sectional shape and area along the length of the cartridge). The cartridge is typically substantially cylindrical. The cartridge typically comprises a casing. The case optionally protects and/or retains the gas separating material. At least part of the casing (optionally at least part of a lateral portion of the casing) is optionally permeable to oxygen-enhanced or oxygen-depleted gas. This is typically achieved by providing at least part of the casing (optionally at least part of a lateral portion of the casing) with pores for egress therethrough of oxygen-enhanced or oxygen-depleted gas. The casing may comprise a substantially prismatic portion, typically an elongate prismatic portion, at least part of the prismatic portion being permeable to oxygen-depleted or oxygen-enhanced gas. The casing may comprise a cylindrical portion, for example, at least part of the cylindrical portion being permeable to oxygen-enhanced or oxygen-depleted gas. At least part of the cylindrical portion may comprise pores for egress therethrough of oxygen-enhanced or oxygen-depleted gas.

[0018] The cartridge may comprise a first end portion associated with the inlet and a second end portion associated with the first outlet. The cartridge may comprise at least one spacer for maintaining the cartridge casing in spaced relationship with the module housing, thereby defining a space for the receipt of oxygen-enhanced or oxygen-depleted gas between the module housing and the cartridge casing. The cartridge may comprise two such spacers. The cartridge optionally comprises a first spacer at or near a first end of the cartridge associated with the inlet and a second spacer at or near a second end of the cartridge associated with the first outlet.

100191 The module may comprise a filter located upstream of the gas separating material located in the cartridge. The cartridge may comprise said filter. The filter removes contaminants and therefore may increase the lifetime of the gas separating material located in the cartridge.

[0020] The gas separating material may be provided in the form of fibres or tubes for the passage therethrough of gas to be separated. Said fibres or tubes may extend from at or near the first end of the cartridge to at or near the second end of the cartridge. The end of the fibres or tubes associated with the inlet may be supported by a first gas-impermeable support. The end of the fibres or tubes associated with the first outlet may be supported by a second gas-impermeable support. The gas-impermeable supports ensure that the inlet gas has to pass through the fibres or tubes comprising the gas separating material. The first and/or second gas impermeable supports may comprise resin or adhesive. This allows the fibres or tubes to be spaced in a non-solid resin or adhesive precursor which is then hardened.

100211 The gas separation module may be provided with insulation around at least part of the module housing. The insulation may be removable (for example, by providing an insulating blanket). Insulation may be provided around at least the central portion of the module housing (if present). Insulation may be provided around substantially all of the module housing.

[0022] According to a second aspect of the invention there is also provided a cartridge for use in the gas separation module of the first aspect of the present invention. The cartridge of the second aspect of the present invention may comprise those features described above in relation to the gas separation module of the first aspect of the present invention. For example, if the gas separation module is an aircraft gas separation module, the cartridge may optionally comprise gas separating material for reducing the oxygen content of a gas flow. Alternatively, if the gas separation module is for use in the medical industry, the cartridge optionally comprises gas separating material for increasing the oxygen content of a gas flow.

[0023] According to a third aspect of the present invention there is also provided an aircraft compartment inerting system comprising: an aircraft gas separation module according to the first aspect of the present invention arranged to receive a flow of oxygen-containing gas and one or more conduits for delivering oxygen-depleted gas to at least one aircraft compartment.

[0024] Those skilled in the art will realise that the at least one aircraft compartment is not part of the aircraft compartment inerting system.

[0025] The aircraft gas separation module may be arranged to receive a flow of oxygen-containing gas from an aircraft engine, typically from the aircraft engine bleed.

[0026] The aircraft compartment inerting system may comprise an ozone remover configured to remove ozone from a gas stream. The ozone remover is optionally located upstream of the aircraft gas separation module because ozone may damage parts of the aircraft gas separation module.

[0027] The aircraft compartment inerting system may comprise a cooler configured to cool a gas stream. A cooler is of particular benefit if the oxygen-containing gas is at a high temperature, for example, if the oxygen-containing gas is obtained from an engine bleed. The cooler may comprise a heat exchanger, for example. The aircraft compartment inerting system may comprise a bypass configured to bypass the cooler. This allows part of a gas stream to bypass the cooler to facilitate greater control of gas temperature. 100281 The cooler may be located upstream of the ozone remover (if present), or may be located downstream of the ozone remover.

[0029] The aircraft compartment inerting system may comprise one or more particulate filters. The particulate filter(s) may be located upstream of the aircraft gas separation module.

[0030] The aircraft compartment inerting system may comprise one or more conduits for delivery of oxygen-depleted gas to one or more aircraft compartments to be inerted. 100311 The aircraft compartment inerting system may comprise one or more valves operable to control the flow of gas there past.

[0032] According to a fourth aspect of the present invention, there is provided a method of maintaining a gas separation module according to the first aspect of the present invention, the method comprising replacing an at least partially used cartridge with a new cartridge. One or both of the at least partially used cartridge and the new cartridge may optionally comprise a cartridge in accordance with the second aspect of the present invention.

[0033] According to a fifth aspect of the present invention, there is also provided a method of maintaining an aircraft compartment inerting system comprising a gas separation module according to the first aspect of the present invention, the method comprising replacing an at least partially used cartridge with a new cartridge. One or both of the at least partially used cartridge and the new cartridge may optionally comprise a cartridge in accordance with the second aspect of the present invention.

100341 The aircraft compartment inerting system may comprise an aircraft compartment inerting system in accordance with the third aspect of the present invention.

100351 It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. -8 -

DESCRIPTION OF THE DRAWINGS

[0036] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: 100371 Figure I shows a schematic cross-sectional view through an air separation module according to a first embodiment of the invention; 100381 Figure 2 shows a schematic view of an aircraft compartment inerting system according to a second embodiment of the invention; and 100391 Figure 3 shows a schematic view of an aircraft comprising the aircraft compartment inerting system of Figure 2.

DETAILED DESCRIPTION

100401 An example of an aircraft gas separation module for producing a flow of oxygen-depleted gas according to an embodiment of the invention will now be described with reference to Figure 1. The aircraft gas separation module is denoted generally by reference numeral 1 and comprises an inlet 2 for the introduction of a gas flow comprising at least two components, one of which is oxygen, a first outlet 3 for the egress of the gas flow depleted in oxygen, a module housing 4 and a removable cartridge 5 located within the module housing 4 and located in a gas flow path between the inlet 2 and the first outlet 3, said cartridge 5 comprising a gas separating material 6 for depleting the amount of oxygen in the gas flow.

100411 The module 1 takes an inlet gas ("IA" in Fig. 1 -inlet air) from an air source (typically an engine bleed valve) and produces a first outlet gas ("ODA" in Fig. I -oxygen-depleted air) which leaves via first outlet 3 and is then fed to an aircraft compartment which requires an inert atmosphere (such as a fuel tank). The module 1 also produces a second outlet gas ("OEA" in Fig. 1 -oxygen-enhanced air) which leaves the module via a second outlet 7. The structure and function of the module 1 will now be discussed in more detail.

[0042] The cartridge 5 comprises a porous cylindrical casing 8 made from a rigid plastics material. The casing 8 is provided with multiple pores 9 which permit gas to leave the -9 -cartridge as will be explained below. The rigid casing 8 helps protect the gas separating material 6 and facilitates simple handling of the cartridge 5. The gas separating material 6 is in the form of fibres or small tubes 10 down which input air IA is passed. Such tubes are used in conventional air separation modules, such as those sold by Parker Filtration & Separation BV, Etten-Leur, Netherlands. One end 11 of each tube 10 is fixed in a gas-impermeable fibre support 13 made from glue or resin and the other end 12 of each tube 10 is fixed in a gas-impermeable fibre support 14 made from glue or resin. Each support 13,14 is substantially disk-shaped. Each end of the cartridge 5 is provided with an annular spacer 15, 16 which holds the casing 8 in spaced relationship to the module housing 4. Each spacer 15, 16 is provided with an annular seal 17, 18 for forming a gastight seal between the cartridge 5 and the module housing 4. The benefit of the seals 17, 18 will be discussed below. The cartridge 5 comprises a charcoal filter 19 upstream of the gas separating material 6. The charcoal filter 19 removes undesirable contaminants from input air IA, thereby extending the life of the cartridge 5 by extending the life of the gas separating material 6.

[0043] The module housing 4 comprises a central portion 20, inlet cap 21 and outlet cap 22. Each of the inlet cap 21 and outlet cap 22 is provided with a screw thread 23, 24 which engages with a corresponding screw thread 25, 26 provided on a respective end of the module housing central portion 20. The screw threads facilitate the removal of the inlet and outlet caps to facilitate replacement of the cartridge 5. Each of the inlet 21 and outlet 22 caps comprises a skirt portion 26, 27 and a dome portion 28, 29. The inlet 2 is provided in the dome portion 28 of inlet cap 21. The first outlet 3 is provided in the dome portion 29 of outlet cap 22. A space 30, 31 is formed between the cartridge 5 and the respective inlet cap 21 and outlet cap 22. An annular space 32 is provided between the cartridge casing 8 and module housing central portion 20. Second outlet 7 provides an outlet for gas in annular space 32.

100441 The small tubes 10 comprise a gas separation membrane (not shown) which separates gases, oxygen having a greater propensity than nitrogen to pass laterally through the sides of the tubes 10, therefore nitrogen is retained in the tubes 10 while oxygen migrates laterally out of the tubes 10.

-10 - 100451 An insulation blanket 40 is wrapped around the central portion of the module housing 4. This helps maintain the gas at a desired temperature. Alternatively, the insulation blanket 40 may be wrapped around the entire module casing 4.

100461 The operation of the module 1 will now be described. Inlet air IA passes into the module 1 via inlet 2 and into space 30. The air then passes through charcoal filter 19 which removes contaminants from the inlet air. Inlet air then passes into tubes 10. The inlet air cannot pass through support 13 because it is gas-impermeable. Furthermore, annular seal 17 forms a seal between cartridge 5 and module housing 4, thereby inhibiting passage of inlet air past the seal 17. Inlet air cannot therefore bypass the tubes 10. As indicated above, tubes 10 comprise gas separating material 6 for which oxygen has a greater affinity than nitrogen. Oxygen passes laterally through the sides of the tubes 10, leaving oxygen-depleted air inside the tubes 10. Oxygen-depleted air (ODA) passes through the ends 12 of the tubes 10 into the space 31 between the cartridge Sand outlet cap 22. This oxygen-depleted air then passes through first outlet 3. The gas which passes laterally through the walls of the tubes 10 is oxygen-enriched air (OFA). This gas passes through pores 9 in the cartridge casing 8 into the annular space 32 between the cartridge casing 8 and the module housing 4, and then outlet of the module via second outlet 7. The gas-impermeable supports 13, 14 and seals 17, 18 inhibit flow of OEA out of the ends of the cartridge 5.

[0047] The OEA is then typically ejected from the aircraft while the ODA is then used to inert a fuel tank, for example, as will be described below.

[0048] An example of an aircraft compartment inerting system according to an embodiment of the present invention will now be described with reference to Figures 2 and 3. The aircraft compartment inerting system is denoted generally by reference numeral 50 and comprises an inerting system inlet 100 (in this case, air is obtained from an engine bleed) and a gas separation module 1 as described above configured to take gas from the engine bleed via the inerting system inlet 100 and remove oxygen therefrom, providing oxygen-depleted air for supply to aircraft compartments to be inerted (in this case, fuel tanks 200, 300, 400, 500) via conduits 101-105. The aircraft compartment inerting system 50 further comprises an ozone remover 116 configured to remove ozone from the gas feed. Ozone has an adverse effect on the gas separation module 1. Having passed through the ozone remover 116, gas then passes through a heat exchanger 112 which is used to cool the gas from about 350°C to about 50-100°C. A bypass 113 is provided so that some gas does not pass through the heat exchanger 112, thereby providing better control of the cooling of the gas. The bypass is provided with a valve 114 to permit operation of the bypass 113. The gas is then passed through a particulate filter 115 which removes particulate which may adversely affect the operation of the gas separation module I. Gas then passes into the gas separation module 1, typically with an oxygen content of about 21% by volume. After passing through the gas separation module 1 the gas has an oxygen content of about 4-12% by volume. The aircraft compartment inerting system further comprises a valve 117 operable to control the flow of oxygen-depleted air into fuel tanks 200, 300, 400, 500. The pressure of the gas in the inerting system is typically about 20-55 PSI.

[0049] The locations of the system air inlet 100, air separation module I and fuel tanks 200, 300, 400, 500 are shown in Fig. 3. The system air inlet 100 is typically connected to an engine bleed. The air separation module 1 is typically located in the belly fairing and the fuel tanks 200, 300, 400, 500 are located in the wings of the aircraft.

[0050] The cartridge 5 may be replaced as required by the user. When it is desired to replace a cartridge any conduits (not shown) attached to the inlet 2 and first outlet 3 are disconnected. The inlet cap 21 is then unscrewed from the module housing central portion 20 and removed. The cartridge 5 may then be removed from the module 1. A new cartridge (not shown, but essentially identical to removed cartridge 5, save for it not having been used) is then inserted into the module housing central portion 20 until the end of the new cartridge abuts an annular end-stop 33 provided at the end of module housing central portion 20. Tnlet cap 21 is then replaced.

100511 Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

-12 - 100521 The example above shows the use of a gas separation module to provide a flow of oxygen-depleted gas. It is possible for the gas separation module to provide a flow of oxygen-enhanced gas, for example, by using different appropriate gas separating material, such as that found in the EnOxy® modules of Parker. Modules producing oxygen-enhanced gas may be of particular use on the medical field.

[0053] The example above shows the use of fibres comprising air separation material. Those skilled in the art will realise that other arrangements of air separation material may be used.

[0054] The example above demonstrates the use of an air separation module to supply oxygen-depleted gas to fuel tanks. The oxygen-depleted gas may be used to inert other aircraft compartments, such as a hold, for example.

100551 The example above demonstrates the use of a cylindrical cartridge and module housing. Those skilled in the art will realise that other arrangements are possible. [0056] Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.