Patent Application
20160272339
The present invention relates to fuel tank inerting systems, and more particularly to a filter apparatus of an aircraft fuel tank inerting system.
Fuel tank inerting systems are used to reduce the risk of fire or fuel tank explosions. Fuel tank inerting systems use air separation modules (ASMs) to separate oxygen from a fluid stream, such as ambient air, to generate an inert, nitrogen-enriched, stream of fluid that can be delivered to the fuel tanks to replace the air/fuel mixture that exists above the liquid fuel. Prior to entering the ASM, the fluid stream is filtered through an air filter to remove impurities that could reduce the effectiveness of the ASM, such as particulate matter and oil. On-board aircraft fuel tank inerting systems, generally referred to as On-Board Inert Gas Generating Systems (OBIGGS), may also require converting ozone, which is present in the upper atmosphere. A single air filter may be used to filter all impurities as well as convert ozone to oxygen.
Different aircrafts may require fuel tank inerting systems of varying capacities depending on the size of the fuel tank. For systems with greater demand, the quantity of ASMs is simply increased, while the size of each ASM remains the same. In contrast, the number of air filters is not increased in accordance with the number of ASMs. Instead, air filters are sized to accommodate the total demand of the system. Because fuel tank inerting systems of varying capacities require varying sizes of air filters, the air filters are not interchangeable from one system to another and must be uniquely designed for each system.
In one aspect, an aircraft fuel tank inerting system includes a filter apparatus and an air separation module configured to separate oxygen from a fluid stream. The filter apparatus includes a housing unit with a fluid inlet port configured to receive a first fluid stream, a fluid outlet port configured to deliver a second fluid stream, and a plurality of filter cartridges. Each of the plurality of filter cartridges is substantially the same and positioned within the housing unit. The air separation module is in fluid communication with the filter apparatus.
In another aspect, a method of assembly and use of a filter apparatus for an aircraft fuel tank inerting system includes the steps of stacking a plurality of filter cartridges in a housing unit, sealing a gap between an adjacent pair of filters, injecting a first fluid stream into the common fluid shaft or common fluid reservoir, collecting a portion of the first fluid stream having been filtered by at least one of the plurality of filter cartridges, and delivering the filtered fluid stream through an outlet port on the housing unit to an air separation module. The filters are stacked in a row such that open central cavities of each of the plurality of filter cartridges are aligned to create a common fluid shaft. The plurality of filters are also spaced apart from an inner housing wall to create a common fluid reservoir. Sealing the gap between an adjacent pair of filters maintains the common fluid shaft and the common fluid reservoir.
In yet another aspect, an aircraft fuel tank inerting system includes a filter apparatus and an air separation module in fluid communication with the filter apparatus and configured to separate oxygen from a fluid stream. The filter apparatus includes a housing unit with a fluid inlet port configured to receive a first fluid stream and a fluid outlet port configured to deliver a second fluid stream to the air separation module, a filter having an open central cavity in direct fluid communication with either the fluid inlet port or the fluid outlet, a non-filtering element with a height substantially the same as a height of the filter, and a reservoir surrounding an outer perimeter of the filter and in direct fluid communication with the fluid inlet port or fluid outlet port not in direct fluid communication with the common fluid shaft. The filter and the non-filtering element are stacked together within the housing unit.
The present summary is provided only by way of example, and not limitation. Other aspects of the present disclosure will be appreciated in view of the entirety of the present disclosure, including the entire text, claims and accompanying figures.
While the above-identified figures set forth embodiments of the present invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features, steps and/or components not specifically shown in the drawings.
The housing unit 18 in the illustrated embodiment holds a plurality of filter cartridges 22 (shown in phantom) to accommodate the multiple ASMs 30. The housing consists of two pieces—the header 16, through which the fluid inlet port 14 and fluid outlet port 26 are positioned, and a lower bowl 32, which holds the plurality of filter cartridges 22. The header 16 and lower bowl 32 can be secured together with a threaded connection, a v-band clamp, or other suitable fastening mechanism capable of creating an airtight seal to prevent fluid from leaking out of the filter apparatus 20. The housing unit 18 can be made of aluminum or an aluminum alloy. Alternatively, the housing unit 18 can be made of steel or similar material suited to high-temperature environments or can be made of plastic. It will be understood by one skilled in the art that the material used for manufacture of the housing unit 18 will depend on the environment in which it is operating.
Each of the plurality of filter cartridges 22 can have multiple membranes 42, 46, 48 configured to remove different impurities or unwanted components of the fluid stream. Each of the plurality of filter cartridges 22 in
The impurities removed by the filter apparatus 20 include at least one of particulate matter, oil, and ozone. Ozone is of particular concern in the design of filters for on-board aircraft fuel tank inerting systems because ozone is present in the ambient air of the upper atmosphere. Ozone may not be of concern in the design of filters for use in on-ground fuel tank inerting systems.
The liquid drain 44 shown in
As shown in
Each end cap 50, 52 is configured to detachably mate with an adjacent end cap 50, 52, such that the top end cap 50 of one filter can be removably secured to the bottom end cap 52 of an adjacent filter in the stack. Adjacent end caps 50, 52 form a sealed connection to prevent fluid from passing through a gap between two adjacent filter cartridges 22. The end caps 50, 52 can be made of a hard material, such as an aluminum alloy, or other material suited to the environment and capable of forming a seal with an adjacent end cap 50, 52. The filter cartridge 22 shown in the embodiment of
The threaded seals 54, 56 or similar attachment and sealing mechanisms of the top and bottom end caps 50, 52 also connect with the fluid inlet port 14 in the header 16 of the housing unit 18 and the lower bowl 32 of the housing unit 18, respectively, to prevent fluid from bypassing the plurality of filter cartridges 22. Each of the plurality of filter cartridges 22 are substantially the same with regard to structure, dimensions, and composition, and therefore, are interchangeable. Each of the plurality of filter cartridges 22 can attach to another filter cartridge 22 or to the header 16 or lower bowl 32 of the housing unit 18. In addition, any single filter cartridge 22 can be replaced without replacing the remaining filter cartridges 22.
In one embodiment, the fluid stream 12 enters the filter membrane 42, 46, 48 through the common fluid shaft 40. Once the fluid stream 12 has passed through the filter membrane 42, 46, 48, it is collected in a reservoir 66 that surrounds the outer perimeter of the plurality of filter cartridges 22. The reservoir 66 is in direct fluid communication with the fluid outlet port 26 on the housing unit 18. The filtered fluid stream 24 exits the housing unit 18 through the fluid outlet port 26 and enters a passive manifold 28 where it is directed to one or more ASMs 30. Both the fluid outlet port 26 and fluid inlet port 14 are equipped with pressure relief valves 62, 64, which can release fluid if the fluid pressure exceeds a predetermined value.
Although in the embodiments discussed and shown, the fluid inlet port 14 is in direct fluid communication with the common fluid shaft 40 and the fluid outlet port 26 is in direct communication with the reservoir 66. It will be understood by one skilled in the art that the fluid flow path can be reversed. In other words, the fluid inlet port 14 and fluid outlet port 26 can be interchanged, such that the fluid outlet port 26 is connected with the unfiltered fluid stream 12 and the fluid inlet port 14 is connected to the one or more ASMs 30. In this construction, the fluid stream 12 is directed to the reservoir 66 and enters the filter body 38 from the outermost perimeter of the filter cartridge 22. The filtered fluid stream 24 exits into the common fluid shaft 40 from which it is directed to the one or more ASMs 30. It will further be understood by one skilled in the art that the sequence of filter membranes 42, 46, 48 can be changed to best accommodate fluid flow in this direction.
In one embodiment, a non-filtering element 58 replaces a filter cartridge 22 in the filter apparatus 20, such that the filter apparatus 20 contains one filter cartridge 22 and one non-filtering element 58 (both shown in phantom). It will be understood by one skilled in the art that the number of filter cartridges 22 each filter apparatus 20 holds is limited by the size of the housing unit 18 and that the housing unit 18 can be designed to hold more or less filter cartridges 22 to accommodate the demand of the fuel tank inerting system 10.
The following are non-exclusive descriptions of possible embodiments of the present invention.
A fuel tank inerting system includes a filter apparatus and an air separation module. The filter apparatus has a housing unit with a fluid inlet port configured to receive a first fluid stream, a fluid outlet port configured to deliver a second fluid stream, and a plurality of filter cartridges, which are substantially the same and are positioned within the housing unit. The air separation module is in fluid communication with the filter apparatus and configured to separate oxygen from the second fluid stream.
The fuel tank inerting system of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
A further embodiment of the foregoing fuel tank inerting system, wherein each of the plurality of filter cartridges has a height less than a height of the housing unit and the plurality of filter cartridges has a total height less than the height of the housing unit.
A further embodiment of the foregoing fuel tank inerting system, wherein each of the plurality of filter cartridges is a cylinder with an open central cavity extending along a length of the cylinder and a filter membrane extending from a perimeter of the open central cavity to an outermost diameter of the filter cartridge.
A further embodiment of the foregoing fuel tank inerting system, wherein the plurality of filter cartridges are stacked in a row such that the open central cavities of each of the plurality of filter cartridges are aligned to create a common fluid shaft in direct fluid communication with one of the fluid inlet port or fluid outlet port.
A further embodiment of the foregoing fuel tank inerting system, wherein each of the plurality of filter cartridges has a first and second sealing member and, wherein the first sealing member is configured to mate with the second sealing member of an adjacent filter cartridge and prevent the first fluid stream from entering a gap between adjacent filter cartridges while maintaining the common fluid shaft.
A further embodiment of the foregoing fuel tank inerting system, wherein a top portion of the housing unit is configured to mate with the first sealing member and prevent the first fluid stream from entering a gap between an uppermost filter cartridge and said top portion of the housing unit, and wherein a base of the housing unit is configured to mate with the second sealing member to prevent the first fluid stream from entering a gap between a lowermost filter cartridge and the base of the housing unit.
A further embodiment of the foregoing fuel tank inerting system having a liquid drain positioned at a lowermost end of the housing unit below the plurality of filter cartridges.
A further embodiment of the foregoing fuel tank inerting system, wherein the plurality of filter cartridges are each configured to remove at least one of the group consisting of particulate matter, ozone, and oil from the first fluid stream.
A further embodiment of the foregoing fuel tank inerting system having a reservoir, which surrounds an outermost diameter of the plurality of filter cartridges.
A further embodiment of the foregoing fuel tank inerting system, wherein the reservoir is in direct fluid communication with the one of the inlet port or outlet port not in direct fluid communication with the common fluid shaft.
A further embodiment of the foregoing fuel tank inerting system having a non-filtering element, wherein the non-filtering element has a height substantially the same as a height of each of the plurality of filter cartridges and wherein the non-filtering element is positioned in the housing unit in place of one of the plurality of filter cartridges.
A further embodiment of the foregoing fuel tank inerting system, wherein the second fluid stream comprises a portion of the first fluid stream having been filtered by at least one of the plurality of filter cartridges.
A method of assembly and use of a filter apparatus for a fuel tank inerting system, includes the steps of: stacking a plurality of filter cartridges in a housing unit, wherein the plurality of filter cartridges are stacked in a row such that open central cavities of each of the plurality of filter cartridges are aligned to create a common fluid shaft and are spaced apart from an inner housing wall to create a common fluid reservoir; sealing a gap between an adjacent pair of filters while maintaining the common fluid shaft and the common fluid reservoir; injecting a first fluid stream into the common fluid shaft; collecting a second fluid stream, wherein the second fluid stream comprises a portion of the first fluid stream having been filtered by at least one of the plurality of filter cartridges; and delivering the second fluid stream through an outlet port on the housing unit to an air separation module.
A further embodiment of the foregoing method of assembly and use of a filter apparatus including the step of stacking an additional filter in the housing unit based on a quantity of air separators receiving the second fluid stream.
A further embodiment of the foregoing method of assembly and use of a filter apparatus including the step of stacking a non-filtering element with the plurality of filter cartridges in the housing unit, wherein the non-filtering element has a height substantially the same as a height of each of the plurality of filter cartridges.
An aircraft fuel tank inerting system includes a filter apparatus and an air separation module. The filter apparatus has a housing unit with a fluid inlet port configured to receive a first fluid stream and a fluid outlet port configured to deliver a second fluid stream; a filter having an open central cavity in direct fluid communication with one of the fluid inlet port or fluid outlet port; a non-filtering element with a height substantially the same as a height of the filter; and a reservoir surrounding an outer perimeter of the filter and in direct fluid communication with the one of the fluid inlet port or fluid outlet port not in direct fluid communication with the open central cavity. The filter and the non-filtering element are stacked together within the housing unit. The air separation module is in fluid communication with the filter apparatus and configured to separate oxygen from the second fluid stream.
Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally”, “approximately” and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, alignment or shape variations induced by thermal, rotational or vibrational operational conditions, and the like.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
