An EMC fluid filter

Abstract

A fluid filter 10 is integrally formed to have a filter medium having a filter structure 20, the filter structure permitting the flow of a fluid from a first side of the filter structure to a second side of the filter structure, and a non-filter medium 12 connected to the filter medium. The filter medium and non-filter medium are formed together from one or more materials, such as polymers, ceramics or preferably metals, as a seamless unitary component, preferably by additive manufacturing, eg 3-d printing. The filter is preferably an air filter for an intake a helicopter or other aircraft. Figure 26 shows an aircraft body with a duct 1100 forming part of a filter assembly for filter 10. Figures 1 (and 13 to 19) show how filter medium 20 and a non-filter medium 12 comprising a support means and possibly a mounting means 13. The filter assembly may have a water drainage duct (300 fig 17) and comprise water permeable 200a, and water impermeable 200b portions. The filter medium part may have various geometries / shapes (see figures 2-14). The filter assembly may have various shaped ducts for aircraft (figures 20-26).

Description

FIELD Embodiments of the present invention relates to an EMC fluid filter. More particularly, this invention relates to an EMC fluid filter for use with an air filtration system. BACKGROUND Fluid filters are used to in many applications to separate an undesired fluid from another fluid, or to separate other undesired materials from a fluid such as dust or debris. In one example, a fluid filter may be used to separate water or other liquids, or solid particulate matter such as dust from air flowing into a volume or zone, such as a room of a building or the interior of a vehicles. Such volumes or zones may be occupiable by humans, animals or cargo. Due to the widespread proliferation of electrical and electronic devices, it is also often a requirement that such filters are electromagnetic compatible, such that they function appropriately in the electromagnetic environment they are intended to operate within. Such filters are used in various applications to separate electromagnetically protected volumes or zones from surrounding volumes or zones. The filter may act to absorb electromagnetic waves, whilst allowing fluid movement, particularly air, to pass into and from the protected volume or zone. The present invention seeks to alleviate one or more problems associated with the prior art. BRIEF DESCRIPTION OF THE INVENTION According to a first aspect of the invention, we provide an EMC fluid filter including: a filter medium having a filter structure, the filter structure permitting the flow of a fluid from a first side of the filter structure to a second side of the filter structure; a non-filter medium connected to the filter medium; and wherein the filter medium and the non-filter medium are formed together from one or more materials as a seamless unitary component. The filter medium and the non-filter medium may be formed from one or more materials as a seamless unitary component by using at least one additive manufacturing technique or process and using any suitable additive manufacturing apparatus. The non-filter medium may include at least one support structure which enables the EMC fluid filter to be connected to another component. The filter structure may include a plurality of fluid flow passages, each fluid flow passage at least partially defined by a plurality of walls, each fluid flow passage having a first opening positioned at or near the first side of the filter structure and a second opening positioned at or near the second side of the filter structure. At least one wall of at least one fluid flow passage may include an aperture extending through said wall. At least one wall of at least one fluid flow passage may include a plurality of apertures each extending through said wall. At least one wall of at least one fluid flow passage may be: a) substantially planar; or b) substantially non-planar. The first opening of at least one fluid flow passage may be: a) substantially the same cross-sectional shape as the second opening of the at least one fluid flow passage; or b) of a different cross-sectional shape as the second opening of the at least one fluid flow passage. At least a portion of at least one fluid flow passage may extend in a direction relative to an axis of the filter structure, and wherein the at least one portion of the at least one fluid flow passage may extend: a) in a direction substantially parallel to the axis of the filter structure; or b) in a direction substantially inclined to the axis of the filter structure. At least a portion of at least one fluid flow passage may twist about an axis which intersects the first opening and second opening of said fluid flow passage. Each of the plurality of fluid flow passages may be substantially identical, and the plurality of fluid flow passages may form a tessellated filter structure. The filter structure may include a plurality of wire elements. The plurality of wire elements may each extend in a direction relative to an axis which intersects the first side of the filter structure and the second side of the filter structure, the plurality of wire elements may include: a) at least one wire element which extends in a direction which is substantially parallel relative to said axis; and / or b) at least one wire element which extends in a direction which is substantially perpendicular relative to said axis; and / or c) at least one wire element which extends in a direction which is substantially inclined relative to said axis. The plurality of wire elements may each extend along an axis, the plurality of wire elements may include: a) at least one wire element extending substantially linearly along said axis; and / or b) at least one wire element extending substantially non-linearly along said axis. The plurality of wire elements may include: a) at least one wire element having a substantially circular cross-sectional profile; and / or b) at least one wire element having a substantially non-circular cross-sectional profile. The plurality of wire elements ofthe filter structure may be arranged in a three-dimensional crystalline structure. The three-dimensional crystalline structure may be at least partially formed as one of, or a combination of, the following Bravais lattice structures: a) a cubic lattice structure; b) a tetragonal lattice structure; c) an orthorhombic lattice structure; d) a hexagonal lattice structure; e) a trigonal lattice structure; f) a monoclinic lattice structure; and / or g) a triclinic lattice structure. At least two wire elements may be connected by a wall element. The filter structure may twist about an axis which intersects the first side of the filter structure and the second side of the filter structure, and the axis may be: a) positioned substantially centrally relative to the filter structure; or b) positioned substantially off-centre relative to the filter structure. The filter medium may include a plurality of filter structures, each filter structure having any of the features described above. The EMC fluid filter may further include at least one drainage port, and optionally a drainage layer, for directing a fluid present in the filter medium towards the at least one liquid drainage port, and further optionally the at least one drainage port, drainage layer, support structure and filter medium may be formed together from one or more materials as a seamless unitary component. The EMC fluid filter may further include at least one protective member which extends over at least a portion of the filter medium, and optionally the at least one protective member, support structure and filter medium may be formed together from one or more materials as a seamless unitary component. The EMC fluid filter may further include at least one fluid guide member for altering the direction of a fluid flow: a) towards the filter medium; and / or b) through the filter medium; and / or c) exiting the filter medium, and optionally the at least one fluid guide member, support structure and filter medium may be formed from one or more materials as a seamless unitary component. According to a second aspect of the invention we provide an air filtration assembly including at least one EMC fluid filter having any of the features described above. The EMC fluid filter may be formed as an integral component of at least a part of the air filtration assembly. According to a third aspect of the invention we provide an aircraft including one or more EMC fluid filters, each EMC fluid filter having any of the features described above. According to a fourth aspect of the invention we provide a helicopter including one or more EMC fluid filters, each EMC fluid filter having any of the features described above. BRIEF DESCRIPTION OF THE FIGURES In order that the present disclosure may be more readily understood, preferable embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a front perspective view of an EMC fluid filter in accordance with the present disclosure; FIGURE 2 is a perspective view of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 3 is a side cross-section view of the filter structure of Figure 2 about a plane X; FIGURE 4 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 5 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 6 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 7 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 8 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 9 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 10 is a perspective view of a part of a filter structure of an EMC fluid filter with an exploded view of various cross-sections in accordance with the present disclosure; FIGURE 11 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 12 is a perspective view of a part of a filter structure of an EMC fluid filter in accordance with the present disclosure; FIGURE 13 is a side cross-section view of an disclosure; FIGURE 14 is a side cross-section view of an disclosure; FIGURE 15 is a side cross-section view of an disclosure; EMC fluid filter in accordance with the present EMC fluid filter in accordance with the present EMC fluid filter in accordance with the present FIGURE 16 is a side cross-section view of an EMC fluid filter in accordance with the present disclosure; FIGURE 17 is a side cross-section view of an EMC fluid filter including a drainage port in accordance with the present disclosure; FIGURE 18 is a side cross-section view of an EMC fluid filter including an impact layer and a fluid guide member in accordance with the present disclosure; FIGURE 19 is a side cross-section view of an EMC fluid filter provided as an insert within an existing structure; FIGURE 20 is a side cross-section view of an EMC fluid filter integrated as part of a duct; FIGURE 21 is a side cross-section view of an EMC fluid filter integrated as part of a forward facing scoop; FIGURE 22 is a side cross-section view of an EMC fluid filter integrated as part of a rear facing scoop; FIGURE 23 is a side cross-section view of an EMC fluid filter integrated as part of a flush inlet or outlet; FIGURE 24 is a side cross-section view of an EMC fluid filter integrated as part of a dynamic pressure inlet; FIGURE 25 is a side cross-section view of an EMC fluid filter integrated as part of a dynamic pressure inlet; FIGURE 26 is a perspective view of an EMC fluid filter forming part of an air filtration assembly and provided on a surface of an aircraft. DETAILED DESCRIPTION OF THE DISCLOSURE Referring to the Figures, there is shown an EMC fluid filter 10. The EMC fluid filter 10 includes a filter medium 20 and a non-filter medium 12, which are formed together from one or more materials as a seamless unitary component. The EMC fluid filter 10 may include other features as described below. The EMC fluid filter 10 is formed such that it is electromagnetically compatible, meaning that the EMC fluid filter 10 has the ability to function appropriately in the electromagnetic environment it is intended to operate within, i.e., by absorbed electromagnetic radiation. For example, this may include the ability of the EMC fluid filter 10 to limit any undesirable and / or unintentional interaction with nearby electromagnetic energy sources so that the consequences, such as electromagnetic interference, are reduced or eliminated for nearby components. The EMC fluid filter 10 may, in some embodiments, act as, or form part of, a shield and may inhibit or interrupt coupling paths between other components nearby. The EMC fluid filter 10, including any of its constituent components, may be sized and configured according to the specific requirements of the EMC fluid filter 10 in any given application. An EMC fluid filter 10 is shown in Figure 1, having a filter medium 20 which is surrounded about its periphery by a non-filter medium 12. In some embodiments, the non-filter medium 12 may be, or may include, at least one support structure 13 or a plurality of support structures 13. The non-filter medium 12 may include other components or structures other than support structures. The at least one support structure 13 may at least partially support the filter medium 20 of the EMC fluid filter 10. In embodiments, the support structure 13, or support structures 13, may at least partially surround the filter medium 20. For example, the at least one support structure 13 may be provided as a sleeve, collar, flange, adapter or be otherwise configured to at least partially support the filter medium 20, and in embodiments enable the EMC fluid filter 10, and filter medium 20, to be held in place relative to a body or another component to which a support structure 13 may be removably connected to or permanently connected to, as described in more detail below. In other embodiments, a support structure 13 may be at least partially provided within the filter medium 20. At least a part of the support structure 13 may occupy a volume within the volume of the filter medium 20, and may pass through the filter medium 20 or terminate at a point within the volume of the filter medium 20. For example, a support structure 13 may be provided as a sleeve, collar, flange, adapter or other suitable support structure which at least partially occupies a volume of the filter medium 20. Whilst an EMC fluid filter 10 is shown in Figure 1 having a substantially cylindrical shape, it should be understood that the EMC fluid filter 10, and any of its constituent features or components, may be provided in any shape and / or size depending on the specific requirements of the EMC fluid filter 10. In embodiments, the support structure 13, or support structures 13 of the non-filter medium 12 may include a mounting feature 14, such as an aperture or hole through which a rivet, stud, or bolt may pass through. The mounting feature 14 may be provided as an area or part of a support structure 13, or support structures 13, which may enable support structure 13 to be welded, adhered, bonded, or otherwise connected to a body or another component. In other embodiments, a support structure 13, or support structures 13, may be integrally formed with a part of a body or a component to which the EMC fluid filter 10 is to be held relative to, such as being integrally formed with a part of a body of an air duct or filtration assembly 1100 or a part of a vehicle or aircraft 1000. In other embodiments, a support structure 13 may be integrally formed such that the EMC fluid filter 10 is held relative to a storage container, a room of a building, an item or protective equipment, or any other appropriate body, volume or component. The EMC fluid filter 10 includes a filter medium 20. The filter medium 20 includes a filter structure 200, or a plurality of filter structures 200. The or each filter structure 200 permits a fluid to flow from a first side 210 of said filter structure 200 to a second side 212 of said filter structure 200. In other words, the or each filter structure 200 is arranged such that a fluid may pass through the filter structure 200, and at least partially through the filter medium 20 constituted by the filter structure 200. In embodiments wherein the filter medium 20 includes a plurality of filter structures 200, the filter structures 200 may be arranged relative to each other in any suitable manner, depending on the specific requirements of the EMC fluid filter 10. In some embodiments, a first filter structure 200a may be arranged such that fluid is permitted to flow from its first side 210a to its second side 212a, and second side 212a of the first filter structure 200a may be in fluid communication with a first side 212b of a second filter structure 200b which is arranged such said fluid is permitted to flow from its first side 210b to its second side 212b. In other words, a first and second filter structure 200a, 200b may be arranged such that a fluid passed through the first filter structure 200a and then subsequently through a second filter structure 200b, such that a fluid has flowed through the filter medium. In other embodiments, a first filter structure 200a and a second filter structure 200b may be arranged such that a fluid flows into the first side 212b of the second filter structure 200b without first flowing through a first filter structure 200. For example, a first and second filter structure 200a, 200b may be arranged in a side-by-side configuration, or one filter structure 200a, 200b may be arranged to surround the other filter structure 200a, 200b, in a concentric arrangement, eccentric arrangement, or other suitable arrangement. The filter structures 200 may be arranged in a plurality of configurations, as discussed in more detail below The EMC fluid filter 10 thus operates to permit the flow of a fluid through it. The EMC fluid filter 10 and filter medium 20 may be configured to permit the flow of various types of fluid, or to permit only a desired type of fluid and inhibit or prevent the flow of undesired types of fluid, e.g., water. The EMC fluid filter 10 and filter medium 20 may be further configured to prevent the flow of various types of solid matter, such as, but not limited to, particulate matter, ice, and debris, or to permit types of solid matter as required. Said solid matter may be suspended in the fluid flowing towards the EMC fluid filter 10, or may be separate to the fluid flowing towards the EMC fluid filter 10. In embodiments wherein the filter medium 20 includes a plurality of filter structures 200, each filter structure 200 may be configured to permit and / or inhibit the flow of the same types of fluids and solid matter, or may be configured to permit and / or inhibit flow of different types of fluids and solid matter, as required for the specific application of the EMC fluid filter 20. The non-filter medium 12 and the filter medium 20 of the EMC filter 20 are formed from one or more materials, and are formed as a seamless unitary component. In addition, other features of the EMC filter 20 which are discussed in detail below may also be form part of the same seamless unitary component. A seamless unitary component has no discernible joins, transitions or seams which result from the way in which the component is manufactured. All parts of at least the nonfilter medium 12 and the filter medium 20 are part of a singular continuous structure, and form one single body which no joins, transitions or seams between any two points of the same continuous structure. For example, there are no parts or locations on the component where two or more individual components have been welded, joined, bonded, adhered or otherwise connected together. The non-filter medium 12 and the filter medium 20 of the EMC filter 10 may be formed from one or more materials as a seamless unitary component by using any suitable additive manufacturing (AM) techniques and processes and using any suitable additive manufacturing apparatus. Additive manufacturing techniques and processes include additive layer manufacturing processes (ALM) which typically involve forming an object in portions, such as layers, of a selected material. Some of these processes include the use of a support or filler material which may be used to support parts of the object during manufacture, and which may be subsequently removed use a variety of known methods to yield a final product. As described above, the EMC fluid filter 10 is electromagnetically compatible, and thus may be wholly or partially formed of at least one material which enables the EMC fluid filter 10 to operate appropriately within an intended electromagnetic environment. Any appropriate material, or materials, may be selected. Such materials may include, but not limited to, metallic materials with satisfactory electromagnetic compatibility, and may also include electrically conductive carbonbased materials, ceramics and polymers and combinations thereof. For an EMC fluid filter 10 which is formed from at least one metallic material, any suitable AM or ALM process may be used such as powder bed fusion processes including: electron beam melting; direct metal laser sintering; selective heat sintering (SHS); selective laser melting (SLM) and selective laser sintering (SLS), or metal binder jetting processes, or directed energy deposition processes, or any other suitable AM or ALM process. If the EMC filter 10 is to be formed as a seamless unitary component from non-metallic materials, it may be formed using any AM or ALM process or processes which may be used with said materials. The use of any suitable AM or ALM process to form at least the non-filter medium 12 and filter medium 20 of an EMC fluid filter 10 as a seamless unitary component has numerous benefits and advantages. A seamless unitary component may be more reliable and have a longer life span compared to a similar component manufactured using traditional techniques and processes. For instance, a filter made using traditional techniques may include sheets of material which are formed into a certain shape or profile, such as a repeating pattern of parts of a hexagonal shape. Multiple sheets may then be welded, bonded, or adhered together to form a repeating pattern of hexagonal shapes to form a filter medium. The resulting filter medium may then be welded, bonded or adhered to a support structure. Not only are these processes time and labour intensive, but each point at which the parts of said filter are welded, bonded, or adhered together, create a seam, join or transition in the filter which may be subject to conditions in which the seam, join or transition fails. Failure at one seam, join or transition may result in undue load being imparted on nearby parts of the component, increasing the likelihood of further failure, and may negatively impact the performance of the component. In addition, the use of adhesives or bonding agents may not be suitable in certain scenarios, such as those where the safe operating temperatures of any material may be a critical factor, or where having significantly differing coefficients of thermal expansion may be undesirable. Additionally, forming at least the non-filter medium 12 and filter medium 20 of an EMC fluid filter 10 as a seamless unitary component, using any suitable AM or ALM process, means that it is possible to manufacture a filter medium 20 with a complex geometry and / or functionality which would not be possible with other processes and techniques. As described in more detail below, a filter medium 20 having complex and / or variable geometric details throughout may be devised which have performance and functional abilities not previously possible with traditional fluid filters. It may be possible to devise a filter medium 20 having a cell or lattice density which varies at different locations on the filter medium 20, or wherein the type of filter structure 200 varies in construction at different locations, such as by twisting or sweeping parts of a filter structure 200. It may also be possible to build additional features or parts into the filter medium 20 without requiring additional manufacturing steps. It is also possible to form the non-filter medium 12, including at least one support structure 13, filter medium 20 and other EMC fluid filter 10 components as part of a larger assembly, such as an air duct or filtration assembly 1100 for a vehicle such as an aircraft 1000, as one example. Another benefit is that an EMC fluid filter 10 may be manufactured with less waste byproduct, due to the nature of AM and ALM processes. This may reduce the overall costs of manufacturing an EMC filter 10, make the production of prototypes cheaper and more expedient, and may have environmental benefits due to the reduction in waste byproducts and potential reduction in scrappage rates of a batch of EMC fluid filters 10. As shown in Figures 2 to 7, a filter structure 200 of the fluid medium 20 may include a plurality of fluid flow passages 220. Each fluid flow passage 220 may be at least partially defined by a plurality of walls 224, and each fluid flow passage 220 may have a first opening 221 positioned at or near the first side 210 of the filter structure 200 and a second opening 222 positioned at or near the second side 212 of the filter structure 200. The fluid flow passage 220 is thus formed such that a fluid may enter the first opening 221, flow through a volume at least partially defined by a plurality of walls 224, and flow out of the second opening 222. It should be understood that both of the first and second opening 221, 222 may allow a fluid flow to enter or exit, meaning that the EMC fluid filter 10 may operate bi-directionally, or uni-directionally, depending on the specific requirements of the EMC fluid filter 10. The walls 224 of each fluid flow passage 220 at least partially define the fluid flow passage 220. In embodiments, the fluid flow passage 200 may be formed such that the plurality of walls 224 entirely define the fluid flow passage 200. In other embodiments, the fluid flow passage 200 may be partially defined by a plurality of walls 224, and also partially defined by a part or surface of the non-filter medium 12 which at least partially supports, or connects to, the fluid medium 20, or may be partially defined by a wall 224 or any other part of another fluid structure 200 which is positioned adjacent the fluid flow passage 200. At least one wall 224 of a fluid flow passage 220 may be configured such that it is substantially planar. In other words, the entirety, or vast majority, of the material or materials forming a wall 224 may reside on a single plane, i.e., it may be described as flat or substantially flat. In other embodiments, at least one wall 224 of a fluid flow passage 220 may be configured such that it is substantially non-planar. The wall 224 may be shaped such that the material or materials forming the wall 224 do not reside on a single plane. The wall 224 may be shaped such that it includes a plurality of connected planar surfaces, or may be curved such that its shape may be described as monoclastic, synclastic, anticlastic or of variable curvature, or arranged in any other suitable way wherein the material or materials forming the wall 224 do not reside on a single plane. In embodiments, a fluid flow passage 220 may include a variety of wall 224 configurations such as having at least one wall 224 which is substantially planar, and having at least one wall 224 which is substantially non-planar. As described above, each fluid flow passage 220 may have a first opening 221 and a second opening 222. Each of the first opening 221 and second opening 222 may have a cross-sectional shape or profile which is at least partially defined by the walls 224 of said fluid flow passage 224. As shown in Figures 2 to 7, the first opening 221 and second opening 222 may be hexagonal in cross-sectional shape or profile. It should be understood that in embodiments the first opening 221 and / or second opening 222 may have any appropriate shape or profile. In embodiments, the cross-sectional shape of the first opening 221 may be the same as, or substantially similar to, the cross-sectional shape of the second opening 222. In such embodiments, the cross-sectional shape may be constant, or substantially constant, throughout the entire fluid flow passage 200. In other embodiments, the cross-sectional shape may not be constant throughout the entire fluid flow passage 200. For instance, the first opening 221 and second opening 222 may be of the same shape, but the shape may change at a distance from either opening along the fluid flow passage 200. This change in shape may include a change from one geometric shape to another, such as changing from a hexagonal shape to a quadrangular shape, and / or it may also include changing a characteristic dimension of the cross-sectional shape such as a width or diameter, and / or a change in rotational orientation of the cross-sectional shape. The cross-sectional shape of the fluid flow passage 220 may in multiple locations along the fluid flow passage 200. In other embodiments, the first opening 221 of a fluid flow passage 220 may have a cross-sectional shape or profile which is different to the cross-sectional shape or profile of the second opening 222. As shown in Figure 7, the first opening 221 of a fluid flow passage 220 may have a cross-sectional profile having a first area A1. The second opening 222 of said fluid flow passage 220 may have a cross-sectional profile having a second area A2, which differs to the first area A1. In embodiments, the cross-sectional shape or profile may differ in any relevant aspect, such as geometric shape, characteristic dimension, orientation, or in any other way. As shown in Figures 4 and 5, at least one fluid flow passage 220 of a filter structure 200 may include at least one aperture 226 which extends through a wall 224 of said fluid flow passage 220. A fluid flow passage 220 may have multiple apertures 226, with each aperture 226 located on a separate wall 224 of the fluid flow passage 226, as shown in Figure 4. The aperture or apertures 226 may be of any required shape and / or size, depending on the specific application of the EMC filter 10. For instance, the aperture or apertures 226 may allow one type, or a selection of types of fluid or solid matter to pass through it but may inhibit a different type or types of fluid or solid passing through it. Such an arrangement may allow for a direction change through of a certain type of matter through the EMC filter 10. A fluid flow passage 220 of a filter structure 200 may include at least one aperture 226 of one configuration, and at least one other aperture 226 of another configuration. For instance, a fluid flow passage 220 may include an aperture 226 of one size and I or shape and / or location, and another aperture 226 of a different size and I or shape and / or location, as required. As shown in Figure 5, a wall 224 of a fluid flow passage 220 may include a plurality of apertures 226. The plurality of apertures 226 may be realised as a perforated section of a wall 224, including many apertures 226. Each aperture 226 within the perforated section of a wall 224 may be substantially the same size and / or shape, or the perforated section may including apertures 226 of differing size and / or shape. The plurality of apertures 226 may be arranged in any suitable configuration or pattern, as required. A fluid flow passage 220 may include only one wall 224 having a plurality of apertures 226, multiple walls 224 having a plurality of apertures 226, or any combination of walls 224 having on aperture 226 and walls 224 having a plurality of apertures 226. Similar to as described above, these various configurations enhance the possible functionality of a filter structure 200. As shown in Figure 6, a fluid flow passage 220 may extend in the direction of an axis B. Axis B may intersect the area of the first opening 221 and the area of the second opening 222. In some embodiments, the fluid flow passage 220 may twist or be otherwise swept about the axis B. The fluid flow passage 220 may have a first opening 221 and a second opening 222 having a similar, or the same, cross-sectional shape or profile which twists as the fluid flow passage 220 extends in the direction or axis B. In other embodiments, the fluid flow passage 220 may have a first opening 221 and a second opening 222 having a different cross-sectional shapes or profiles which twist as the fluid flow passage 220 extends in the direction or axis B. The characteristics of the twist of the fluid flow passage 220 may be selected based on the specific requirements of the EMC filter 10, and may increase the performance and functionality of the EMC filter 10. At least a portion of, or the entirety of, a fluid flow passage 220 may extend in the direction of an axis A of a filter structure 200, which may be an axis which intersects the area of the first side 211 of the filter structure 200 and the area of the second side 212 of said filter structure 200. In embodiments, at least a portion of a fluid flow passage 220 may extend in a direction which is parallel, or substantially parallel, to the axis A of the filter structure 200. In other embodiments, at least a portion of a fluid flow passage 220 may extend in a direction which is substantially inclined relative to the axis A of the filter structure 200. The orientation of at least a portion of, or the entirety of, a fluid flow passage 220 relative to the axis A of a filter structure 200 may be selected based on the specific requirements of the EMC filter 10, and may enhance the performance and functionality of the EMC filter 10. For instance, a fluid flow passage 220 which extends in a direction which is inclined relative to the axis A may allow for finer control of the direction of fluid flow through a filter structure 200. In embodiments, the filter structure 200 may include a plurality of fluid flow passages 220 which are identical, or substantially identical such as varying only by virtue of manufacturing tolerances and capabilities of the apparatus used to form the fluid flow passages 220. The plurality of fluid flow passages 220 may be arranged to form a tessellated filter structure 200, as shown in Figures 2 to 4. In other embodiments, the filter structure 200 may include a plurality of fluid flow passages 220 which include different combinations of any of the features described above for a fluid flow passage 220. With reference to Figures 8 to 12, the filter structure 200 may include a plurality of wire elements 232. Each wire element 232 of the plurality of wire elements 232 extends in a direction relative to an axis A which intersects the first side 210 of the fluid structure 200 and intersects the second side 212 of the filter structure 200. In embodiments, at least one wire element 232, or a plurality of wire elements 232, of the filter structure 200 may extend in a direction which is parallel, or substantially parallel, relative to the axis A of the filter structure 200. In other embodiments, at least one wire element 232, or a plurality of wire elements 232, of the filter structure 200 may extend in a direction which is perpendicular, or substantially perpendicular, relative to the axis A of the filter structure 200. In yet further embodiments, at least one wire element 232, or a plurality of wire elements 232, of the filter structure 200 may extend in a direction which is inclined, or substantially inclined, relative to the axis A of the filter structure 200. In embodiments of a filter structure 200 including a plurality of wire elements 232, the filter structure 200 may include wire elements 232 which extend all in the same direction, for example, they may all extend in a direction which is substantially parallel to the axis A of the filter structure 200. In other embodiments, the filter structure 200 may include any combination of pluralities of wire elements 232 which extend in the directions described above. For example, a plurality of wire elements 232 may extend in a direction which is substantially parallel relative to the axis A of the filter structure 200, and a plurality of wire elements 232 may extend in a direction which is substantially perpendicular relative to the axis A of the filter structure 200. In embodiments, any of the plurality of wire elements 232 may connect to a part of the non-filter medium 12, which may include one or more support structures 13. Additionally, in embodiments, any of the plurality of wire elements 232 may connect to another of the plurality of wire elements 232, which may result in the formation of a lattice structure 230, which may form at least part of a filter structure 200. In such embodiments, at least a portion of one wire element 232 may pass at least partially through at least a portion of another wire element 232 of the plurality of wire elements 232, such that the two wire elements 232 are connected. One wire element 232 may be connected to multiple wire elements 232 in this manner, and may additionally be connected to the non-filter medium as described above. In other embodiments, each wire element 232 which may be connected to another, or multiple, wire elements 232 may connect to a common node element 234. In Figures 8 to 12, the node elements 234 are shown as substantially spherical, but it should be understood that the node elements 234 may be formed in any appropriate shape which enables wire elements 232 to be connected together, and node elements 234 of different shapes and sizes may be combined in one lattice structure 230 depending on the specific requirements of the filter structure 200 it forms at least a part of. With reference to Figure 11, each wire element 232 extends in a direction relative to a wire element axis C. In embodiments, at least a portion of at least one wire element 232 may extend substantially linearly along a wire element axis C, meaning that it does not significantly curve or otherwise deviate relative to the wire element axis C. In other words, the wire element 232, or a portion thereof, may extend in a straight line. In other embodiments, at least one wire element 232 may extend non-linearly relative to the wire element axis C. For instance, at least a portion of the wire element 232 may be curvilinear, or may be otherwise shaped such that at least a portion of the wire element 232 deviates from the axis C. It should be understood that a lattice structure 230 of a filter structure 200 may have any combination of wire elements 232 as described above, such as a combination of a plurality of wire elements 232 which extend linearly and a plurality of wire elements 232 which extend non-linearly, as shown in Figure 11. With reference to Figure 10, each wire element 232 has a cross-sectional shape or profile. In embodiments, at least one wire element 232 of the plurality of wire elements 232 may have a substantially circular cross-sectional shape or profile. In other embodiments, at least one wire element 232 of the plurality of wire elements 232 may have a cross-sectional shape or profile which is non-circular. Figure 10 shows some examples non-circular profiles, but it should be understood that a wire element 232 may have any appropriate shape or profile depending on the specific requirements of the EMC filter 10. In some embodiments, the cross-sectional shape or profile of a wire element 232 may be substantially constant throughout the wire element 232. In other embodiments, the cross-sectional shape or profile of a wire element 232 may not be consistent through the wire element 232, or at least a portion of the wire element 232. In some embodiments, the filter structure 200 may include a plurality of wire elements 232 which are all of the same cross-sectional shape or profile, or in other embodiments the filter structure 200 may include a plurality of wire elements 232 having differing cross-sectional shape or profile in any appropriate combination. With reference to Figure 12, at least two wire elements 232 of the plurality of wire elements 232 may be connected by a wall element 236. A filter structure 200 may include a plurality of wall elements 236. A wall element 236 may be configured such that its entire perimeter connects to a number of wire elements 232, as shown in Figure 12. In other words, the wall element 236 may form a surface which entirely occupies or spans an area or space which extends between a plurality of wire elements 232. In other embodiments, a wall element 236 may be configured such that only a portion of its perimeter connects to a wire element 232, or a plurality of wire elements 232, and wherein the remaining portion of its perimeter is not connected to a wire element 232. In such an embodiment, the wall element may form a surface which only partially occupies or spans an area or space which extends between a plurality of wire elements 232. At least one wall element 236 of a filter structure 200 may be substantially planar, such that it is essentially flat. In other embodiments, at least one wall element 236 of a filter structure may be substantially non- planar, and may be shaped such that it includes a plurality of connected planar surfaces, or may be curved such that its shape may be described as monoclastic, synclastic, anticlastic or of variable curvature, or arranged in any other suitable way wherein the material or materials forming the wall element 226 do not reside on a single plane. In embodiments, a lattice structure 230 may include a variety of wall element 226 configurations such as having at least one wall element 226 which is substantially planar, and having at least one wall element 226 which is substantially non-planar. The wall elements 236 described above may be arranged such that they may enhance the performance of the filter structure 200. For instance, they may allow for a direction change of a fluid flowing through the filter structure 200, or they may serve to separate a fluid flow into separate streams which may be directed in different directions, or they may enable two or more types of fluid or solid matter to be separated. As described above, the plurality of wire elements 232 of a filter structure 200 may be arranged to form a lattice structure 230, and each wire element 232 may be configured as described above, and connect to other wire elements 232 or to the non-filter medium 12 as described above. In embodiments, and as shown in Figures 8 to 12, at least a part of the lattice structure 230 may be formed as a three-dimensional crystalline structure. The lattice structure 230 may include wire elements 232 which are all substantially the same, or may include any combination of wire elements 232 as described above. The lattice structure 230 of a fluid structure 230 may be at least partially formed as one of, or any combination of, Bravais lattice structures as known in the art. These Bravais lattice structures may include, where appropriate, simple, base-centered, body-centred and facecentered variations of: cubic lattice structures; tetragonal lattice structures; orthorhombic lattice structures; hexagonal lattice structures; trigonal lattice structures; monoclinic lattice structures; and triclinic lattice structures. Depending on the specific requirements of the EMC fluid filter 10, the lattice structure 230 may include any number and combination of three-dimensional crystalline structures. In embodiments, the filter structure 200 may include a plurality of wire elements 232 which include different combinations of any of the features or arrangements described above and may be formed as a lattice structure 230 or a plurality of lattice structures which are arranged in any combination as described above. With reference to Figures 13 and 14, a filter structure 200 formed either from a plurality of fluid flow passages 220 or a plurality of wire elements 232 as described above, may be twisted or otherwise swept about an axis A which intersects the first side 210 of the filter structure 200 and the second side 212 of the filter structure 200. In embodiments, only a portion of a filter structure 200 may twist or be otherwise swept about the axis A of the filter structure 200. This may be any portion, or multiple portions, of the filter structure 200. In the embodiment shown in Figure 13, the entire filter structure 200 may twist or be otherwise swept about the axis A of the filter structure 200. As also shown in Figure 13, the axis A may be positioned substantially centrally relative to the filter structure 200, such that the twist or sweep of the filter structure 200 occurs about the centre, or near centre, of the filter structure 200. In other embodiments, the axis A of the filter structure 200 may be positioned substantially off-centre relative to the filter structure 200, such that the twist or sweep of the filter structure 200 occurs about a location of the filter structure 200 which is not at the centre of the filter structure 200, but is offset from the centre of the filter structure 200. As described above, the filter medium 20 may include a plurality of filter structures 200. Each of these filter structures 200 may differ in its combination of any of the features described above for a filter structure 200 including a plurality of fluid flow passages 220, or a plurality of wire elements 232. Each of these filter structures 200 may be arranged relative to other filter structures 200 forming the filter medium 20 in any appropriate layout or arrangement. For example, Figure 15 shows an EMC filter 10 in which a first filter structure 200a is positioned such that its first side 210a at least partially forms an exterior surface or face of the filter medium 20. This first filter structure 200a may be formed from a plurality of fluid flow passages 220, or a plurality of wire elements 232, as described above. The filter medium 20 may also include a second filter structure 200b, which is positioned such that its second side 212b at least partially forms an exterior surface or face of the filter medium 20. In this example, the second side 212a of the first filter structure 200a and the first side 210b of the second filter structure 200b are positioned adjacent, or substantially in contact with each other, and such that they are in fluid communication to enable a fluid, or only a desired fluid or fluids, to pass through the EMC filter 10. Figure 16 shows another example of an EMC filter 10, in which a first filter structure 200a is radially bounded by a second filter structure 200b. In other words, the second filter structure 200b concentrically surrounds the first filter structure 200a. In the example shown, the first side 210a of the first filter structure 200a and the first side 210b of the second filter structure 200b are positioned such that they reside on a common plane, and the second side 212a of the first filter structure 200a and the second side 212b of the second filter structure 200b are positioned such that they also reside on a common plane. However, it should be understood that the filter structures 200a, 200b may be of different relative sizes, meaning that the first sides 210a, 210b and / or the second sides 212a, 212b of each filter structure 200a, 200b do not reside on common planes. As such, the filter medium 20 may have a stepped or staggered construction or appearance, depending on the relative positioning of the first sides 210a, 210b and / or second sides 212a, 212b, and additionally dependent on the number of filter structures 200 are arranged. It should also be understood that each individual filter structure 200 may be shaped in any appropriate manner, depending on the specific requirements of the EMC filter 10. For example, in embodiments a filter structure 200 may be formed as a substantially prismatic three-dimensional shape or polyhedra, such as a disc, cylinder, cube, cuboid, or any other prismatic three-dimensional shape or polyhedra. In other embodiments, the filter structure 200 may be formed as a non-prismatic three-dimensional shape or polyhedra, such as a frustoconical filter structure, a spherical filter structure, a frustopyramidal filter structure, or any other non-prismatic three-dimensional shape or polyhedral. In addition, in further embodiments, the filter structure 200 may be at least partially formed such that it may have a recessed portion, and / or may have portions which project from the filter structure 200. For instance, a portion of the filter structure 200 may be castellated. Such portions may be included within filter structure 200 to enable the EMC fluid filter 10 to at least partially accommodate other components. For example, in an air duct or filtration system 1100, it may be desirable for the EMC fluid filter 10 to be able to partially accommodate part of an item of electrical equipment such as a motorised fan, a light source or communication equipment. Figure 17 shows an embodiment of an EMC fluid filter 10 which includes at least one drainage port 300. The drainage port 300 may be formed as a part of the non-filter medium 12, as part of one or more support structures 13, or may be provided as a separate component which may be permanently connected or removably connected to a part of the EMC fluid filter 10. In some embodiments, the at least one drainage port 300 may formed together with the non-filter medium 12 and filter medium 20 from one or more materials as a seamless unitary component. The at least drainage port 300 may be provided on any part of the EMC fluid filter 10, and may be sized appropriately depending on the specific requirements of the EMC fluid filter 10. In embodiments, an EMC fluid filter 10 may also include a drainage layer 302. The drainage layer 302 may be provided as a filter structure 200, or a plurality of filter structures 200, including any combination of features as described above. For example, the drainage layer 302 may be a first filter structure 200a which enables a liquid, such as water, to flow through it. A second filter structure 200b may be provided adjacent to the first filter structure 200b which may enable air to flow through it, but which does not enable a liquid such as water to flow through it. The first filter structure 200a may include features which enable the liquid, such as water, to be directed towards a drainage port 300, or multiple drainage ports 300. In some embodiments, the drainage layer 302 may be formed separately to the EMC fluid filter 10 and may be permanently or removably connected to a part of the EMC fluid filter 10. In other embodiments, the drainage layer 302 may formed together with the non-filter medium 12 and filter medium 20 from one or more materials as a seamless unitary component. The at least one drainage layer 302 may be provided on any part of the EMC fluid filter 10, and may be sized appropriately depending on the specific requirements of the EMC fluid filter 10. Figure 18 shows an embodiment of an EMC fluid filter 10 which includes at least one protective member 400, and at least one fluid guide member 500. The at least one protective member 400 may extend or otherwise be positioned over at least a portion of the filter medium 20, and for example may be formed of a material or materials which may be impact-resistant, impact-absorbent, or sacrificial. In use, it may protect the filter structure 20, or any part of the EMC fluid filter 10 from sources of potential damage. The at least one protective member 400 may be formed such that it enables a fluid to flow through it, and thus may be formed as a filter structure 200 including any of the features described above. In other embodiments, it may be configured such that it does not enable the flow of a select fluid or solid matter, or any matter, through it. For example, the protective member 400 may partially cover the filter medium 20, and the filter medium 20 may have a fluid structure 200 which enables fluid to flow through a part of it which is exposed to the environment, and fluid may be able to flow underneath the protective member 400, by inclusion of any appropriate combination of any of the features of a fluid structure 200 described above. In some embodiments, the protective member 400 may be formed separately to the EMC fluid filter 10 and may be permanently or removably connected to a part of the EMC fluid filter 10. In other embodiments, the protective member 400 may formed together with the non-filter medium 12 and filter medium 20 from one or more materials as a seamless unitary component. The at least one protective member 400 may be provided on any part of the EMC fluid filter 10, and may be sized appropriately depending on the specific requirements of the EMC fluid filter 10 and may be included on an EMC fluid filter 10 which also includes at least one drainage port 300 and at least one drainage layer 302, as described above. In embodiments, and as shown in Figure 18, an EMC fluid filter 10 may include at least one fluid guide member 500 which, in use, may alter or guide the direction of a fluid flow towards, through, and / or exiting the fluid medium 20. Depending on the specific requirements of the EMC fluid filter 10, the at least one fluid guide member 500 may be optimally shaped and sized to guide a fluid in a specific direction. In the example shown in Figure 18, a plurality of fluid guide members 500 are positioned such that they extend beyond the filter structure 200a, and into the environment surrounding the EMC fluid filter 10. Thus, a flow of fluid from the external environment may be guided towards the filter medium 20. The plurality of fluid guide members 500 also extend into the filter structure 200a, meaning that they may also guide the flow of a fluid through a portion of the filter medium 20. In other embodiments, the at least one fluid guide member 500 may be provided such that it extends entirely through the filter medium 20, or does not pass through the filter medium 20 at all. In some embodiments, the at least one fluid guide member 500 may be formed separately to the EMC fluid filter 10 and may be permanently or removably connected to any part of the EMC fluid filter 10. In other embodiments, the at least one fluid guide member 500 may formed together with the non-filter medium 12 and filter medium 20 from one or more materials as a seamless unitary component. The at least one fluid guide member 500 may be provided on any part of the EMC fluid filter 10, and may be sized appropriately depending on the specific requirements of the EMC fluid filter 10 and may be included on an EMC fluid filter 10 which also includes at least one drainage port 300 and at least one drainage layer 302, and / or at least one protective member 400, as described above. As shown in figures 19 to 26, an EMC fluid filter 10 may be provided as part of an air filtration assembly 1100, which enables the EMC fluid filter 10 to provide filtration and ventilation to a part a volume of space which may be occupied by humans, animals or cargo. For instance, the air filtration assembly 1100 may be provided on a vehicle 1000, such as a helicopter as shown in Figure 26. A vehicle 1000 may include a singular air filtration assembly 1100 and / or EMC fluid filter 10, or may include a plurality of air filtration assemblies 1100 and / or a plurality of EMC fluid filters 10. In other embodiments, an EMC fluid filter 10 may be provided as part of an air filtration assembly 1100, which enables the EMC fluid filter 10 to provide filtration and ventilation to a part a volume of space such as a storage container, a room of a building, or may be provided as part of an item or protective equipment, or any other appropriate body, volume or component. In other embodiments, an air filtration assembly 1100 may include a plurality of EMC fluid filters 10. Figure 19 shows an EMC fluid filter 10 which is provided as an insert such that it may be permanently connected to or removably connected to a part of an existing structure, such as an air filtration assembly 1100. In an embodiment, the EMC fluid filter 10 may be inserted into an aperture provided on a part or component of an air filtration assembly 1100, and may be held in place using a plurality of fasteners, such as a plurality of threaded bolts. In other embodiments, the EMC fluid filter 10 may be inserted into an aperture provided on a part or component of an air filtration assembly 1100 and may be welded, bonded or adhered to a part or component of an air filtration assembly 1100. The air filtration assembly 1100 may be formed as part of an aircraft 1000, such as a helicopter or tiltrotor craft, or any other suitable aircraft 1000. As shown in Figure 20, an EMC fluid filter 10 may be provided as part of an EMC air filtration assembly 1100 which forms part of a duct, which may provide filtration of a fluid flow and / or ventilation to a part of an aircraft 1000, or from a part of an aircraft 1000. Figure 21 shows an EMC fluid filter 10 which may be provided as part of an air filtration assembly 1100 which forms part of a forward facing scoop of an aircraft 1000. Figure 22 shows an EMC fluid filter 10 which may be provided as part of an air filtration assembly 1100 which forms part of a rear facing scoop of an aircraft 1000. Figure 23 shows an EMC fluid filter 10 which may be provided as part of an air filtration assembly 1100 which forms part of a flush inlet or outlet of an aircraft 1000. Figure 24 shows an EMC fluid filter 10 which may be provided as part of an air filtration assembly 1100 which forms part of a dynamic pressure inlet of an aircraft 1000. Figure 25 shows an EMC fluid filter 10 which may be provided as part of an air filtration assembly 1100 which forms part of a dynamic pressure outlet of an aircraft 1000. In any of the applications of an EMC fluid filter 10 described above, the EMC fluid filter 10 may be formed as an integral component of an air filtration assembly 1000. For instance, the EMC fluid filter 10 and at least a part of an air filtration assembly 1100 may be formed together from one or more materials as a seamless unitary component, using any appropriate AM or ALM processes or techniques as described above. With reference to Figure 26, the air filtration assembly 1100 may include a body or component which may function as a scoop or a cowl, which may guide a flow of fluid towards an EMC fluid filter 10, and may also protect the EMC fluid filter 10 from external sources of potential damage. The EMC fluid filter 10 may be permanently connected to or removably connected to a part of the air filtration assembly 1100, or may be formed as an integral component of at least a part of the air filtration assembly 1100. For instance, in some embodiments, the non-filter medium 12 may include a part of the air filtration assembly 1100, such that a part of the air filtration assembly 1100 may be a support structure 13. The air filtration assembly 1100 may include features which enable it to be permanently connected to or removably connected to a part of an aircraft 1000, such as a helicopter or any other suitable aircraft. Depending on the specific requirements of an aircraft 1000, the interconnection of an air filtration assembly 1100 and an EMC fluid filter 10 may be arranged as required. In embodiments, a non-filter medium 12 of an EMC fluid filter 10 may include at least one mounting feature 14 which enables the EMC fluid filter 10 to be connected to a part of the air filtration assembly 1100. As such, the EMC fluid filter 10 may be removed from the air filtration assembly as a separable component, such that it may be inspected, maintained, and I or replaced. In other embodiments, the EMC fluid filter 10 may be formed as an integral component of at least a part of the air filtration assembly 1100 such that the entire air filtration assembly 1100, including the EMC fluid filter 10, may be connectable to, and removable from, an aircraft 1000 as a singular component. This may reduce the complexity and / or increase the speed of assembling an aircraft 1000, or may be beneficial from a maintenance perspective as it may not required to remove multiple components to access a part of an air filtration assembly 1100. In addition, it may thus be possible to produce the air filtration assembly 1100, or at least a part of the air filtration assembly 1100, using one AM or ALM technique which may significantly reduce the occurrence of waste byproducts and scrappage, and reduce the time taken to manufacture the air filtration assembly 1100. When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. The invention may also broadly consist in the parts, elements, steps, examples and / or features referred to or indicated in the specification individually or collectively in any and all combinations of two or more said parts, elements, steps, examples and / or features. In particular, one or more features in any of the embodiments described herein may be combined with one or more features from any other embodiment(s) described herein. Protection may be sought for any features disclosed in any one or more published documents referenced herein in combination with the present disclosure. Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and / or to encompass equivalents.

Claims

1. An EMC fluid filter including:a filter medium having a filter structure, the filter structure permitting the flow of a fluid from a first side of the filter structure to a second side of the filter structure;a non-filter medium connected to the filter medium; andwherein the filter medium and the non-filter medium are formed together from one or more materials as a seamless unitary component.

2. An EMC fluid filter according to claim 1 wherein the non-filter medium includes at least one support structure which enables the EMC fluid filter to be connected to another component.

3. An EMC fluid filter according to claim 1 or claim 2 wherein the filter structure includes a plurality of fluid flow passages, each fluid flow passage at least partially defined by a plurality of walls, each fluid flow passage having a first opening positioned at or near the first side of the filter structure and a second opening positioned at or near the second side of the filter structure.4 An EMC fluid filter according to claim 3 wherein at least one wall of at least one fluid flow passage includes an aperture extending through said wall.

5. An EMC fluid filter according to claim 3 or 4 wherein at least one wall of at least one fluid flow passage includes a plurality of apertures each extending through said wall.

6. An EMC fluid filter according to any of claims 3 to 5 wherein at least one wall of at least one fluid flow passage is:a) substantially planar; orb) substantially non-planar.

7. An EMC fluid filter according to any of claims 3 to 6 wherein the first opening of at least one fluid flow passage is:a) substantially the same cross-sectional shape as the second opening of the at least one fluid flow passage; orb) of a different cross-sectional shape as the second opening of the at least one fluid flow passage.

8. An EMC fluid filter according to any of claims 3 to 7 wherein at least a portion of at least one fluid flow passage extends in a direction relative to an axis of the filter structure, and wherein the at least one portion of the at least one fluid flow passage extends:a) in a direction substantially parallel to the axis of the filter structure; orb) in a direction substantially inclined to the axis of the filter structure.

9. An EMC fluid filter according to any of claims 3 to 8 wherein at least a portion of at least one fluid flow passage twists about an axis which intersects the first opening and second opening of said fluid flow passage.

10. An EMC fluid filter according to any of claims 3 to 9 wherein each of the plurality of fluid flow passages are substantially identical, and wherein the plurality of fluid flow passages form a tessellated filter structure.

11. An EMC fluid filter according to any preceding claim wherein the filter structure includes a plurality of wire elements.

12. An EMC fluid filter according to claim 11 wherein the plurality of wire elements each extend in a direction relative to an axis which intersects the first side of the filter structure and the second side of the filter structure, the plurality of wire elements including:a) at least one wire element which extends in a direction which is substantially parallel relative to said axis; and / orb) at least one wire element which extends in a direction which is substantially perpendicular relative to said axis; and I orc) at least one wire element which extends in a direction which is substantially inclined relative to said axis.

13. An EMC fluid filter according to claim 11 or 12 wherein the plurality of wire elements each extend along an axis, the plurality of wire elements including:a) at least one wire element extending substantially linearly along said axis; and / orb) at least one wire element extending substantially non-linearly along said axis.

14. An EMC fluid filter according to any of claims 11 to 13 wherein the plurality of wire elements includes:a) at least one wire element having a substantially circular cross-sectional profile; and I or b) at least one wire element having a substantially non-circular cross-sectional profile.

15. An EMC fluid filter according to any of claims 11 to 14 wherein the plurality of wire elements of the filter structure are arranged in a three-dimensional crystalline structure.

16. An EMC fluid filter according to claim 15 wherein the three-dimensional crystalline structure is at least partially formed as one of, or a combination of, the following Bravais lattice structures:a) a cubic lattice structure;b) a tetragonal lattice structure;c) an orthorhombic lattice structure;d) a hexagonal lattice structure;e) a trigonal lattice structure;f) a monoclinic lattice structure; and / org) a triclinic lattice structure.

17. An EMC fluid filter according to any of claims 11 to 16 wherein at least two wire elements are connected by a wall element.

18. An EMC fluid filter according to any preceding claim wherein the filter structure twists about an axis which intersects the first side of the filter structure and the second side of the filter structure, and wherein the axis is:a) positioned substantially centrally relative to the filter structure; or b) positioned substantially off-centre relative to the filter structure.

19. An EMC fluid filter according to any preceding claim wherein the filter medium includes a plurality of filter structures, each filter structure in accordance with any preceding claim.

20. An EMC fluid filter according to any preceding claim further including at least one drainage port, and optionally a drainage layer, for directing a fluid present in the filter medium towards the at least one liquid drainage port, and further optionally wherein the at least one drainage port, drainage layer, support structure and filter medium are formed together from one or more materials as a seamless unitary component.

21. An EMC fluid filter according to any preceding claim further including at least one protective member which extends over at least a portion of the filter medium, and optionally wherein the at least one protective member, support structure and filter medium are formed together from one or more materials as a seamless unitary component.

22. An EMC fluid filter according to any preceding claim further including at least one fluid guide member for altering the direction of a fluid flow:a) towards the filter medium; and / orb) through the filter medium; and / orc) exiting the filter medium, andoptionally wherein the at least one fluid guide member, support structure and filter medium are formed from one or more materials as a seamless unitary component.

23. An air filtration assembly including at least one EMC fluid filter according to any preceding claim.5 24. An air filtration assembly according to claim 23 wherein the EMC fluid filter is formed as anintegral component of at least a part of the air filtration assembly.

25. An aircraft including one or more EMC fluid filters, each EMC fluid filter in accordance with any preceding claim.

026. A helicopter including one or more EMC fluid filters, each EMC fluid filter in accordance with any preceding claim.

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