Helical Flow Magnetic Filtration Device

Abstract

A magnetic filtration device to separate contaminant material from a fluid in a housing 11, with one or a plurality of removably mountable fluid directors 25 between an inlet flow port 15 and filtration chamber to impart a helical flow path 23 to the fluid flowing within the separation chamber and about an elongate central magnetic column or core 12; and a kit with multiple fluid directors, preferably optimized for different filtration conditions, e.g. viscosity, temperature, pressure, fluid or particle type, magnet parameters, and the like. The flow director may comprise a series of flow guide fins or bores. A collar 13 may be removably mounted from head 14. The device and use of a kit are designed to improve efficiency, particularly for filtering for industrial working fluids, and internal corrosion of metallic pipes.

Description

Field of invention The present concept relates to a magnetic fluid filtration device to separate contaminant material from a fluid, and in particular, although not exclusively, to a filtration device having a flow director configured to increase the path length of a fluid flowing past a magnetic core within the device. Background A wide range of filtration devices and methods are used for both commercial and domestic applications. For example, conventional water-based central heating systems, including both domestic and commercial, use a heat source such as an oil, gas, air source heat pump, ground source heat pump or electrically powered boiler to circulate hot water through a fluid network that comprises radiators, underfloor heating pipework, hot water tanks and the like interconnected by metallic and non-metallic pipework. Internal corrosion of the metallic components of the network is an endemic problem and has resulted in a number of different approaches to try and alleviate system contamination by circulation of ferrous particles within the system. Industrial applications that utilise a working fluid to provide cooling, lubrication or to remove wear debris from machine processing tools and products, employ fluid fdtration devices to extract particulate matter from the fluid. The cleaned fluid may then be recirculated for further use or more readily disposed of due to the removal of the particulate matter. Without filtration devices, the working fluid quickly becomes heavily contaminated resulting in machine wear and / or failure and may result in inferior surface finishes and even higher defect rates in finished product. In almost all territories, the filtering and cleaning of industrial fluid waste is required prior to discarding. Magnetic filtration devices have been developed and configured to filter the magnetically susceptible particles from these fluid based systems. In a commercial setting, such units may be employed in an on-line capacity, forming part of the fluid circuit during operation of the machinery or production line, side-stream to take a partial amount of the system flow to magnetically filter, or in an off-line state in which the working fluid is diverted or isolated from the production line when inoperative to provide the required filtration. US 2007 / 0090055 Al and WO 2011 / 086370 Al disclose magnetic filtration devices for separating contaminant material from a working fluid having a central magnetic core housed within a separation chamber. Magnetically susceptible particles (iron containing metal) flow within the chamber and around the magnetic core where they are retained by the magnetic circuit whilst contaminant-free fluid exits via an outlet. Similar types of magnetic filtration devices are installed within central heating systems and operate in-line to continually remove ferrous particles from the working fluid within the system. Example magnetic filtration devices are described in WO 2013 / 150293 Al. Filtering efficiency may be increased by increasing the path length by which the fluid travels relative to the stationary magnetic core. Attempts have been made to increase the path length by inducing a helical fluid flow path around the magnetic column. In particular, EP 0119368 Al describes a filtration device to remove scale deposits from drinking water. The filter comprises deflectors formed from eccentric / angled orifices at an inlet end of a filtration chamber. Water flows into the chamber from a central inner tube via the deflectors which create a helical flow path around the central magnetic column. US 2016 / 0151789 Al describes a magnetic filtration device having a helical worm screw extending around a central magnetic core. As fluid flows within a filtration chamber, the worm screw directs the flow as a spiral around the magnetic core from the inlet to the filtration outlet. However, there is a continued need for magnetic filtration devices having improved filtration efficiency, convenience of use and that are not deleterious to other important operational conditions such as maintaining a desired pressure of the working fluid within the fluid network. Summary of the Invention It is an objective of the present concept to provide a magnetic filtration device configured to extend an effective axial length of a magnetic core so as to increase the time by which a fluid and in particular magnetically susceptible contaminant material is present within a magnetic circuit created by the magnetic core. One objective of the present concept is to induce a spiral or helical flow path of the fluid within a filtration chamber around the magnetic core. A yet further specific objective is to impart a helical or spiral flow configuration without any appreciable increase or decrease in pressure across the filtration device relative to a desired working pressure of the fluid and / or the pressure elsewhere in the fluid network. A yet further objective is to be able to easily change the helical or spiral flow configuration to quickly increase or decrease the degree of flow rotation (helical flow path around the magnetic core) within the fluid. It is a yet further specific objective of the present concept to provide a magnetic filtration device being configurable for use with different types of fluid and / or magnetically susceptible material. Accordingly, the inventors provide a magnetic filtration device provided with a fluid director insert component positioned at the device and configured specifically to induce a spiral or helical fluid flow path past a central magnetic core within a filtration chamber. The fluid director is configured specifically to achieve desired characteristics of the helical flow including in particular helical pitch, curvature and torsion. Such characteristics may be achieved via specifically configuring the fluid director to guide and deflect the fluid flow from an inlet region of the device and to adopt the desired spiral pathway with the required orientation / angle being oblique relative to a longitudinal axis of the filter and the magnetic core. The fluid director comprises at least one flow guide to induce the helical flow path. The flow guide may be implemented as a blade, fin, channel, bore, slot, passage or projection and is positioned in the fluid flow path internally within the device downstream of a device fluid flow inlet. Importantly, the fluid director is removably mounted at a predefined position within the device. Such a configuration enables the user to interchange different fluid directors, each director configured differently to induce a different and pre-defined helical flow profile. For example, a first fluid director may be configured to induce the flow having a short pitch relative to a second director having a flow guide to induce fluid flow of enhanced pitch. Whilst each director is interchangeable at the filter, the present device is configured to positionally lock the director at its predefined location such that the director and flow guide are maintained in a static / stationary position during normal operation of the filtration device. That is, the director and the flow guide remain stationary whilst the fluid flows through the filtration device. The director may comprise more than one director, for example a first director providing a first stage to start rotation of the fluid and a director providing a second stage immediately afterwards to aid further rotation. Optionally, the director may comprise segments (or sections) where each segment has a different flow guide. Such a configuration allows more than one rotational / helical pathway for different viscosities of fluid and / or different contaminant types (to allow flow paths that can be maintained optimally). According to a first aspect of the present concept there is provided a magnetic fluid filtration device to separate contaminant material from a fluid comprising: a housing to provide containment of a fluid to flow through the device, the housing, in part, defining an internal chamber; an inlet port to allow a fluid to enter the device and an outlet port to allow the fluid to exit the device; an elongate magnetic core comprising a plurality of magnets and extending axially within the chamber such that a magnetic field generated by the magnetic core is created in a fluid flow path to entrap contaminant material at the magnetic core; and at least one fluid director removably mountable within the device at a position in a fluid flow direction between the inlet port and an axial end of the magnetic core closest to the inlet port, the director having at least one flow guide to induce the fluid to flow within the chamber with a helical path around the magnetic core. Optionally, the at least one flow guide comprises any one or a combination of: a blade; a fin; a channel; a bore; a slot; a passage; a projection extending radially, axially and circumferentially at the fluid director. Optionally, the fluid director may comprise 1 to 15, 1 to 10, 2 to 8, 3 to 8 or 4 to 8 fins or any number of fins so as to create a desired rotational / helical flow path. Optionally, the at least one flow guide extends between a first axial end and a second axial end of a collar and comprises at least one flow guide surface extending in a fluid flow direction between forward and rearward ends and aligned oblique to a longitudinal axis of the device. Optionally, the flow guide surface may comprise a shape and configuration being part helical. Optionally, the flow guide surface may be planar or may be curved. Optionally, the guide surface may be curved in a fluid flow direction between a first axial end and a second axial end. Optionally, the guide surface may be curved in a radial direction between an inner edge and an outer edge. Optionally, the where the flow guide comprises a plurality of blades of fins, each fin or blade comprises the same shape and / or configuration. Optionally, said fins or blades may be of different shapes within the fluid director. Optionally, a spacing between the fins or blades in a circumferential direction around the fluid director is uniform. Optionally, said spacing may be non-uniform. Preferably, in an axial direction, a separation distance between the respective opposing guide surfaces of neighbouring or adjacent fins or blades is greater than an axial thickness of the fins or blades. Such a configuration is advantageous to minimise an effect of each flow guide obstructing the fluid flow so as to maintain a desired fluid pressure within and across the filtration device. Optionally, the device comprises an internal column and wherein the fluid director is configured to be removably mountable on and about the column. Optionally, the device comprises a head, wherein the housing and / or the core are removably attachable to the head, and wherein the fluid director is removably mounted at the head. Preferably, the fluid director is mounted exclusively within the head and does not extend into the filtration chamber and does not axially overlap the magnetic core. Optionally, the column comprises a base section and wherein the fluid director is mountable on and about the column and capable of being trapped axially between the base section and an axial end of the magnetic core. The base section is configured as a radial shoulder extending laterally from the column. Preferably, the base section comprises an internal passageway corresponding to an exit flow passageway being provided in fluid communication with an internal passageway extending within the central column that comprises / corresponds to the central magnetic core. Preferably, the fluid director is located within the device exclusively outside or primarily outside a magnetic field generated by the magnets. Such an arrangement is advantageous to prevent the fluid director becoming blocked with magnetically susceptible material that may be otherwise entrapped by the relatively strong zones of the magnetic field created by the magnetic core. The present device is therefore configured for effective and efficient filtration that specifically avoids premature blockage / filter saturation. Preferably, the fluid director is a separate component relative to the housing, the magnetic core and the head. The fluid director may therefore be interchanged at the present device to allow a user to select different configurations to induce a desired helical flow profile and in particular an effective magnetic core length / time period by which magnetically susceptible contaminant is present within the magnetic flux. Preferably, the fluid director is removably mounted within an inlet duct extending in a fluid flow direction between the inlet port and the chamber. The inlet port may comprise the first and initial inlet port into the present device being the external most port by which fluid enters the filtration device. Such an inlet port is typically provided with screw threads or other friction fit surfaces for connection to suitable connectors forming part of a fluid network. Preferably, the fluid director comprises an annular configuration. Optionally, an axial length of the fluid director is less than half of an axial length of the head. Optionally, an axial length of the fluid director is in a range 10 to 50, 10 to 40, 15 to 35% of an axial length of the head, wherein the ends of the head are defined by axial endmost surfaces of the head (although other percent ranges could be optionally selected for fluid flow performance requirements). A preferred magnetic arrangement comprises magnetic columns having polarities that alternate circumferentially about the longitudinal axis of the filter. Optionally, the array of magnets is configured such that fluid flow pathways are created and maintained within the filter as contamination is captured. Such arrangements may comprise any one or a combination of magnets with weaker field strength, smaller diameter magnets, off-axis magnet placement, multiple smaller magnets located within the fluid chamber to allow preferential fluid pathways, to mitigate blockage to flow and pressure drop increase. Optionally, the housing comprises an air vent and / or fluid drain valve. Optionally, the air vent and / or fluid drain valve is positioned at or towards a lengthwise end of the housing. Optionally, the air vent and / or fluid drain valve comprises a push / press valve mechanism enabling a user to press the value and release air and / or drain fluid from within the device. According to a further aspect of the present concept there is provided a magnetic fluid filtration kit comprising: a housing to provide containment of a fluid to flow through the device, the housing, in part defining an internal chamber; an inlet port to allow a fluid to enter the device and an outlet port to allow the fluid to exit the device; an elongate magnetic core comprising a plurality of magnets and extending axially within the chamber such that a magnetic field generated by the magnetic core is created in a fluid flow path to entrap contaminant material at the magnetic core; and a plurality of fluid directors, each fluid director removably mountable within the device at a position in a fluid flow direction between the inlet port and an axial end of the magnetic core closest to the inlet port, each director having at least one flow guide to induce the fluid to flow within the chamber with a helical path around the magnetic core; wherein each director differs from one another by any one or a combination of: an orientation of the at least one respective flow guide relative to an axis of the elongate magnetic core; a number or multiplicity of the at least one respective flow guide; a configuration of the at least one flow guide; an axial length of the fluid director. Optionally, each collar is configurable so as to be removably mountable within a head of the device. Preferably, the head is releasably attachable to the housing and / or the magnetic core. According to a further aspect of the present concept there is provided a magnetic fluid filtration device to separate contaminant material from a fluid comprising: a housing to provide containment of a fluid to flow through the device, the housing, in part, defining an internal chamber; an inlet port to allow a fluid to enter the device and an outlet port to allow the fluid to exit the device; an elongate magnetic core comprising a plurality of magnets and extending axially within the chamber such that a magnetic field generated by the magnetic core is created in a fluid flow path to entrap contaminant material at the magnetic core; and at least one fluid director mounted or mountable within the device at a position upstream, optionally immediately upstream, of the chamber, in a fluid flow direction through the device, the fluid director configured to induce the fluid to flow within the chamber with a helical path around the magnetic core. Brief description of drawings A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 is an external perspective view of a magnetic filtration device according to a specific implementation of the present concept; Figure 2 is an exploded perspective view of the device of figure 1; Figure 3 A is a side elevation view of a magnetic core forming part of the device of figure 2; Figure 3B is a plan view of the magnetic core of figure 3 A; Figure 4 is a perspective view of a head part of the filtration device of figure 2; Figure 5 is a perspective cross sectional view of the head part of the device of figure 2; Figure 6 is a further cross sectional perspective view of the head part of the device of figure 2; Figure 7 is a perspective view of a fluid director positioned towards an inlet end region of the device of figure 2; Figure 8 is a perspective view of a fluid director according to a further embodiment; Figure 9 is a cross sectional perspective view of a head region of the filtration device of figure 2 comprising the fluid director of figure 8; Figure 10 is a perspective view of a fluid director according to a further embodiment; Figure 11 is a perspective view of the head and magnetic column of the device of figure 2 fitted with the fluid director of figure 10; Figure 12A is a schematic illustration of a helical flow path of a fluid flowing within an elongate filtration chamber having passed a fluid director having a first configuration; Figure 12B is a schematic illustration of a helical flow path of a fluid flowing within an elongate filtration chamber having passed a fluid director having a second configuration; Figure 12C is a schematic illustration of a helical flow path of a fluid flowing within an elongate filtration chamber having passed a fluid director having a third configuration; Detailed description of preferred embodiment of the invention Referring to figure 1, a magnetic filtration device 10 comprises a generally cylindrical elongate housing 11 having a first blind axial end Ila and a second open axial end 1 lb. An elongate magnetic core indicated generally by reference 12 extends axially within housing 11 and is centred on device longitudinal axis 30. As illustrated in figure 3A, core 12 comprises a column of magnets 28, 29 housed within a cylindrical sleeve 26. Core 12 comprises a first axial end 12a collocated at the first axial end Ila and housing 11 and a second axial end 12b collocated at housing second end 1 lb. Each respective second axial ends 1 lb, 12b are removably mounted to extend axially from a head 14. Head 14 comprises a fluid inlet port 15 and fluid outlet port 16 to enable a fluid to enter (flow 21 into device 10) and to exit (flow 22 out of device 10). An elongate filtration chamber 18 is defined axially and radially between housing 11 and core 12, with chamber 18 being defined between an internal surface 19 of housing 11 and an external surface 20 of a cylindrical sleeve 26 that defines an exterior of core 12. Chamber 18 is further defined between the respective axial ends 1 la, 12a and 1 lb, 12b of the housing 11 and core 12. Sleeve 26 comprises a series of slots 17 provided at or towards first axial end 12a. Slots 17 provide a means of passage of a fluid flow 23 from chamber 18 into a return passageway 97 extending axially within core 12 (figures 5 and 9, return flow passageway 43). Fluid 24 is thereby enabled to flow through slots 17 and into passageway 43. A locking collar 13 is capable of positioning over and about housing 11 via a central aperture 13a, referring to figure 2. Housing 11 comprises an annular flange 11c projecting radially outward and having an annular surface configured for abutment / mating against a corresponding annular surface 31 (figure 4) of head 14. Collar 13 comprises internal threads 13b to operate with external threads 32 (figure 4) of head 14. Accordingly, by securing collar 13 onto head 14 via screw threads 13b and 32 (figure 4) housing 11 is positionally locked onto head 14. Referring to figure 2, device 10 comprises a fluid director 25 in the form of an annular ring or collar removably mounted to head 14 (although other shapes of fluid director 25 could be used to fit to the head 14 such as hexagon or square with central hole; the internal cavity shape, although annular, could equally be of any shape so as to allow the other shape of fluid director e.g square shaped cavity for a squared shaped fluid director). Fluid director 25 is described further with reference to figures 4 to 11 and comprises at least one flow guide configured to induce a helical flow path 23 as the fluid flows within chamber 18 from the second axial ends 1 lb, 12b to the first axial ends 1 la, 12a. Referring to figures 3A and 3B, core 12 comprises a plurality of elongate magnetic columns distributed around axis 30. In particular, a first magnetic column 27a comprises a plurality of north polarity magnets 28. A second column 27b comprises a plurality of south polarity magnets 29, with both the north and south polarity magnets 28, 29 positioned end-to-end and extending along the length of core 12 between the respective axial ends 12a, 12b. According to the specific embodiment, core 12 comprises four columns of magnets 27a, 27b that alternate in polarity in a circumferential direction about axis 30 according to a -N-S-N-S- sequence. Such a configuration (in a cross-sectional plane perpendicular to axis 30) provides a lobed-shaped magnetic field as described and illustrated in WO 2013 / 150293. The series of magnets 28, 29 are contained within cylindrical sleeve 26 that extends axially beyond core first end 12a. Slots 17 are provided at the first end 12a of sleeve 26 that extends axially beyond the magnets 28, 29. The slots 17 may be shaped or profiled so as to provide additional means for aiding the spiral flow 23 of the fluid in the internal cavity 33 to enter the slots 17 for exiting the magnetic device 10. When the magnetic filter is first started, there may be trapped air inside the internal cavity 33 so it can be preferable to have an air vent / fluid drain valve 99 (or pressure release valve) as part of the device 10, provided at the top of the housing 11. This valve could be pressed open to release the trapped air. The valve comprises means (not shown) to automatically close the valve when the user has stopped pressing the valve (e.g. spring mechanism). The valve 99 could also be pressed to drain the housing 11 of fluid at the end of operation (for cleaning and maintenance purposes) by allowing an in flow of air. The presence of a non-return valve to limit flow to just air during filling to prevent leaks is desirable. In a preferred embodiment, the valve 99 is a non-return valve to limit flow to just one direction (to prevent any leaks during filling). The present valve 99 is further configured to control and vary flow for emptying. Such that, when pressure is in the system, the flow valve cannot work because the non-return part is ‘on’ and keeps the user safe from any high-pressure spillage risk, but when the system is off and is to be drained, the non-return is ‘off allowing the drain valve to operate to aid emptying the unit. The drain valve 99 has variable flow capability due to the shape of the aperture (more downward press force gives greater hole space for more inflow of air). The aperture may have a profiled shape so that as the valve is pressed further down, the air gap increases allowing more cross-sectional area to be available for air to pass through giving a variable flow rate in the valve linked to the distance the valve is pressed. If a user were to restart the system and turn the flow (and pressure) back on, if they tried to press the drain valve in / down, the non-return valve would near-instantly prevent further flow to prevent leakage of fluid. A spring mechanism or similar may be provided to assist keeping the valve closed when not in use. In an alternative embodiment the valve 99 may be located elsewhere, such as at or near outlet 16, if the device 10 had to be positioned at a different orientation such as upside down (so as to be placed so that controlled air escape and entry is optimised). Such a design provides a filtration system such that if the magnets were to collect the maximum amount of contamination, channels are maintained between the magnets to allow fluid flow so as to prevent blockage, reduce the flow rate and / or cause unacceptable pressure drop. Optionally the device comprises four magnets arranged circumferentially in a -N-S-N-S- arrangement. However, the arrangement could include 2, 4, 6, 8 or more (magnets in pairs) including, by example, larger diameter core embodiments. Equally, the arrangement of the circumferentially arranged -N-S-N-S- magnets may be off set circumferentially / each axial series rotated relative to its nearest axial neighbour along the core 12 to create a skewed magnet arrangement. Such a configuration provides a the magnetic pathways to follow the direction of rotation of the fluid to either aid the rotational flow as contamination builds and / or to provide a better magnetic pathway for contamination to be magnetically attracted, noting that the numbers of magnets around the circumference could also be in multiples of -N-S- pairs. Equally, the arrangement of the circumferentially arranged -N-S-N-S- magnets may have one or more magnets arranged around the circumference weakened in output (such as selecting a lower grade of magnet or a less strong material such as ferrite / ceramic compared to NdFeB or SmCo) to give one slightly weakened collection area for contamination. This weakened zone is selectively repeated axially along the core 12 to create a skewed magnet arrangement for function and advantages detailed above. Referring to figure 4, 5 and 6, head 14 comprises an internal cavity 33 that extends axially between inlet port 15 and the annular end surface 31. Cavity 33 is annular and extends around a central column 45 that is upstanding from a base region of head 14 (collocated at inlet port 15). Referring to figure 5, column 45 does not extend the full axial height of cavity 33 and terminates at a position axially lower / recessed relative to annular end face 31 (but its position could be at or above the annular end face 31 in other embodiments). The (part) annular cavity 33 is defined axially and radially by a radially inner surface 38 and a radially external facing surface 39 of column 45. Column 45 comprises a central internal bore 35 that is provided in fluidic communication with an intermediate bore / passageway 49 that terminates at outlet port 16. A lateral shoulder or flange 40 projects radially from a base portion of column 45 to provide a body / conduit within which passageway 49 projects laterally between bore 35 and outlet port 16. An upper surface 40a of flange 40, in part, defines a base region of cavity 33, with a further base region 40b being axially lower / recessed to surface 40a and positioned immediately downstream of inlet port 15. Column 45 comprises an annular step or shoulder 45a such that column 45 steps radially inward at a terminal axial end section that is terminated by an annular end face 45b. Core 12 comprises an end stop insert 44 having an annular end face 45c configured for positioning to abut column annular end face 45b with core 12 extending axially and mounted at head 14. Core 12 is removably axially mounted to and locked at column 45 via an axial extension of insert 44 being provided with threads 47 engaging with corresponding threads 46 provided at a recess formed in an annular axial end face 45b of column 45. In other embodiments, the fixing could be a bayonet style fixing rather than a threaded fixing, or a press-fit fitting or even a ‘plug and socket’ location fitting method. In a preferred embodiment the fixing design is such so that the magnet core can be repeatably located so the pole positions of the magnets 29 are always in a known expected position relative to the head 14 and the inlet and outlet ports 15 and 16 to allow measurements of the magnetic field performance. For performing such measurements, housing 11 comprises a mounting, in the form of mounting points 98 to either identify ideal measurement location and / or providing means for such a measurement device to be temporarily or permanently located for short, medium or long term measuring purposes. In such an orientation as illustrated in figure 5, core 12 provides an axial extension of column 45, with both column 45 and core 12 extending axially and centred on axis 30 as a unitary elongate structure. Referring to figures 4 and 5, fluid director 25 comprises a plurality of fins 36 that project radially outward from a central collar 37 (although a version with an external collar additionally or alternatively with the fins projecting radially inward could be used). Collar 37 is configured for positioning over and about column 45 and in particular the axial end section axially closest to annular end face 45b. Director 25 is dimensioned radially to be removably insertable / mountable about column 45 such that an annular axial end of collar 37 is configured to abut column step 45a to axially seat director 25 in position about column 45. At least an axial end region 34 of core 12 is radially enlarged so as to overlap radially over a portion of collar 37 to axially lock director 25 both axially and radially in position about column 45 as illustrated in figure 5. In particular, insert 44 (being axial end section of core 12) extends between magnets 28, 29 and annular end face 45b of column 45 with the core 12 and director 25 located in their in-use position as illustrated in figure 5. It is envisaged that the housing 11 could also be modified such that it could have radial and / or axial extensions so it may alternatively or additionally provide means to abut and axially lock the director 25 in place. In the assembled configuration of figure 5, the radially projecting fins 36 span substantially the full radial width of cavity 33 between surfaces 38 and 39. Accordingly, fluid flow through cavity 33 from inlet port 15 into chamber 18 must pass between the array of fins 36. Referring to figures 6 and 7, the annular fluid director 25 comprises a pair of axial grooves 37c recessed into a radially internal facing surface 50 (that is positionable opposed to the radially outer surface 39 of column 45). Column 45 comprises corresponding ridges (not shown) to interfit / cooperate with grooves 37c. This is effective to circumferentially lock director 25 at column 45 within head 14. As illustrated in figure 8 according to a further embodiment, director 25 may comprise a ridge 37b to cooperate with a groove (not shown) at column 45 (according to the further embodiment). Alternatively, and according to the further embodiment of figure 10, director 25 may be circumferentially locked at head 14 via a pin or screw insertable through a locking bore 37e. Alternatively, director 25 may comprise a bayonet fixing means to attach to the head 14. Alternatively, director 25 may comprise a reverse threaded section with threading on the column 45 so the director is screwed into place in the opposite direction to the rotation of fluid flow so that, in operation, the fluid flow maintains the director 25 in a constant screwed in positional state. Referring to figure 7, each fin 36 comprises a leading lengthwise end 54 and a trailing lengthwise end 55 (with respect to a fluid flow direction through device 10 from inlet port 15 to outlet port 16). Each fin 36 also comprises a lengthwise radially inner edge 52 and a lengthwise extending radially outer edge 53. An upper guide surface 56 is defined between the respective ends 54, 55 and edges 52, 53. A corresponding opposite and downward facing surface 57 is similarly defined between the respective ends 54, 55 and edges 52, 53. Each of the fins 36 are distributed radially around the central collar 37 and in particular extend from collar outer surface 51 via their respective inner edges 52. Each fin 36 is separated axially from each respective circumferential neighbouring fin 36 by an axial separation gap 59. Gap 59 provides a passageway for fluid flow between the opposed surfaces 56 and 57 (of neighbouring fins). Each fin 36 is curved along its length between ends 54, 55 and extends circumferentially at least partially around collar 37. That is, each fin 36 is inclined upwardly in the fluid flow direction from inlet port 15 towards chamber 18. This encourages the fluid flow 58 passing between the series of fins 36 to adopt a helical flow path as the fluid emerges from head 14 and flows into chamber 18. As illustrated in figures 5, 6 and 12A to 12C the fluid flow enters the lower region of cavity 33 and flows axially upward between surfaces 39 and 38 to then pass between gaps 59 of fins 36. According to the specific embodiment, director 25 comprises nine fins. A further embodiment is described referring to figures 8 and 9 in which director 25 comprises five fins 36 projecting from a central collar 37 having the same general construction and features as described referring to figure 7. However, according to the further embodiment of figures 8 and 9, fins 36 that have a steeper angle of inclination relative to fins 36 of the embodiment of figure 7 (where the angle of inclination is defined relative to axis 30). According to the embodiment of figure 8, each fin 36 is aligned with a steeper configuration such that the respective guide surfaces 56, 57 of each fin 36 direct the fluid to flow upwardly along axis 30 to a greater extent than the corresponding surfaces 56, 57 of the fins of the embodiment of figure 7. Additionally, a thickness of each fin 36 decreases from the leading axial end 54 to the trailing end 55. Such a configuration facilitates the upward axial helical fluid flow 23 such that a pitch of the fluid flow 23 created by the embodiment of figure 8 is greater than corresponding pitch of the helix created by the embodiment of figure 7. Figures 10 and 11 illustrate a further embodiment of the device 10 comprising an annular director 25 formed as a disc provided with through-bores 61. In particular, the disc comprises a radial flange 60 extending from a central collar 37. Flange 60 comprises an upward facing annular surface 62 and a downward facing annular surface 63 in which bores 61 extend axially between the opposed surfaces 62, 63. According to the specific embodiment, director 25 comprises six bores evenly distributed around flange 60. Each bore 61 is orientated at an oblique angle relative to axis 30. Each bore 61 is defined by a bore surface 56 being the equivalent flow directing guide surface provided by fins 36 of the embodiments of figures 2 to 9. Accordingly, with the disc mounted in position about column 45 as described for the embodiment referring to figures 4 to 9, fluid is directed to flow from inlet port 15 through the lower region 42 of cavity 33 and to flow through each of the bores 61 to impart the helical flow 23 about core 12. As such, the director 25 may comprise any or a combination of fins, holes, slots or other flow-directing shapes to create an array of gaps 59 in order to change in the flow path direction to create a greater or lesser degree of helical rotation. The number of gaps 59 and the size of the gaps 59 are variable depending on the application, for example more viscous materials may require larger gaps perhaps with a reduced degree of rotational flow (a different pitch). And, if a fluid is susceptible to having larger contamination particulates, a larger gap 59 may allow such larger particles to pass by more easily to prevent blockages (although embodiments where the size of gap could vary between edges 52 and 53 to minimise blockage risk and / or embodiments containing more than a single gap to give similar anti-blockage function are envisaged and encompassed herein. In particular, and referring to figures 12A to 12C, flow at cavity region 42 passes in contact with the respective flow guide (36, 61) and into chamber 18. As illustrated with the embodiment of figure 12A, a short helical flow pitch is provided by a director 25 having a greater number of fins that are extend at approximately 45 degrees relative to axis 30. Relative to the fluid flow within inlet passageway 42 (within head 14) fins 36 provide more angled / inclined guide surfaces 56, 57 that force the fluid to adopt a shorter pitch axial flow between chamber ends 1 lb, 12b, Ila, 12a. Figure 12B illustrates a further embodiment in which the fins 36 are slightly more aligned with axis 30 (relative to the embodiment of figure 12A) so as to be less inclined relative to the inlet flow. The director of the embodiment of figure 12B comprises a smaller number of fins relative to the embodiment of figure 12A. Accordingly, the helical flow path within chamber 18 has a longer pitch relative to the embodiment of figure 12A. The further embodiment of figure 12C has a corresponding smaller number of fins, with each fin having an orientation even more aligned with axis 30 so as to be less inclined relative to the inlet flow. Such an arrangement provides a fluid flow with a larger pitch relative to the embodiments of figure 12A and 12B. Accordingly, the director configuration of the embodiment of figure 12A provides a helical flow with a greater path length about core 12 relative to the embodiment of figure 12B and in turn 12C. By having a greater path length there is increased opportunity for the magnets 29 of the core 12 to attract the ferrous contamination to provide better contamination collection. The present filtration device, via the removably insertable fluid directors 25, enables a user to select a desired flow path length and corresponding entrapment time by which magnetically susceptible materials / particles are present within the circuit created by 5 magnets 28, 29. The present device is advantageous to allow a user to select a filtration configuration being optimised for the plurality of different filtration conditions including any one or a combination of fluid viscosity, temperature, pressure, fluid type, magnetically susceptible particle type, particle size, magnetic core type, magnet type and strength in addition to the types of fluid network within which the filtration device is positioned. The 10 present filtration device may be suitable for use within commercial and domestic residential central heating systems and / or industrial processing lines typically associated with the machining of metal items and the like.

Claims

1. A magnetic fluid filtration device to separate contaminant material from a fluid comprising:a housing to provide containment of a fluid to flow through the device, the housing, in part, defining an internal chamber;an inlet port to allow a fluid to enter the device and an outlet port to allow the fluid to exit the device;an elongate magnetic core comprising a plurality of magnets and extending axially within the chamber such that a magnetic field generated by the magnetic core is created in a fluid flow path to entrap contaminant material at the magnetic core; andat least one fluid director removably mountable within the device at a position in a fluid flow direction between the inlet port and an axial end of the magnetic core closest to the inlet port, the director having at least one flow guide to induce the fluid to flow within the chamber with a helical path around the magnetic core.

2. The device as claimed in claim 1 wherein the at least one flow guide comprises any one or a combination of• a blade;• a fin;• a channel;• a bore;• a passage;• a slot;• a projection extending radially, axially and circumferentially at the fluid director.

3. The device as claimed in any preceding claim wherein the at least one flow guide extends between a first axial end and a second axial end of a collar and comprises at least one flow guide surface extending in a fluid flow direction between forward and rearward ends and aligned oblique to a longitudinal axis of the device.

4. The device as claimed in any preceding claim comprising an internal column and wherein the fluid director is configured to be removably mountable on and about the column.

5. The device as claimed in claim 4 comprising a head, wherein the housing and / or the core are removably attachable to the head, and wherein the fluid director is removably mounted at the head.

6. The device as claimed in claim 5 wherein the column comprises a base section and wherein the fluid director is mountable on and about the column and capable of being trapped axially between the base section and an axial end of the magnetic core.

7. The device as claimed in any preceding claim wherein the fluid director is located within the device exclusively outside or primarily outside a magnetic field generated by the magnets.

8. The device as claimed in any preceding claim wherein the fluid director is mounted exclusively outside the chamber, wherein the chamber is defined axially between respective axial ends of the magnetic core and / or the housing.

9. The device as claimed in any preceding claim when dependent on claim 5 wherein the fluid director is a separate component relative to the housing, the magnetic core and the head.

10. The device as claimed in any preceding claim wherein the fluid director is removably mounted within an inlet duct extending in a fluid flow direction between the inlet port and the chamber.

11. The device as claimed in any preceding claim the fluid director comprises an annular configuration.

12. The device as claimed in claims 5 and 11 wherein an axial length of the fluid director is less than half of an axial length of the head.

13. The device as claimed in any preceding claim wherein the housing comprises an air vent and / or fluid drain valve.

14. A magnetic fluid filtration kit comprising:a housing to provide containment of a fluid to flow through the device, the housing, in part defining an internal chamber;an inlet port to allow a fluid to enter the device and an outlet port to allow the fluid to exit the device;an elongate magnetic core comprising a plurality of magnets and extending axially within the chamber such that a magnetic field generated by the magnetic core is created in a fluid flow path to entrap contaminant material at the magnetic core; anda plurality of fluid directors, each fluid director removably mountable within the device at a position in a fluid flow direction between the inlet port and an axial end of the magnetic core closest to the inlet port, each director having at least one flow guide to induce the fluid to flow within the chamber with a helical path around the magnetic core;wherein each director differs from one another by any one or a combination of:• an orientation of the at least one respective flow guide relative to an axis of the elongate magnetic core;• a number or multiplicity of the at least one respective flow guide;• a configuration of the at least one flow guide;• an axial length of the fluid director.

15. The kit as claimed in claim 14 wherein the configuration of the flow guide comprises any one or a combination of:• a blade;• a fin;• a channel;• a bore;• a passage ;• a slot;• a projection extending radially, axially and circumferentially at the fluid director.

16. The kit as claimed in claims 14 or 15 wherein each fluid director comprises a collar and is removable mountable within a head of the device, the head releasably attachable to the housing and / or the magnetic core.

17. The kit as claimed in claim 16 wherein each collar is configured to sit over and about a central column extending within a region of the head.

18. The kit as claimed in claims 16 or 17 wherein each collar is removably mountable within an inlet duct extending in a fluid flow direction between the inlet port and the chamber; andwherein each collar is mountable exclusively outside of the chamber, wherein the chamber is defined axially between respective axial ends of the magnetic core and / or the housing.

19. The kit as claimed in claims 14 or 18 The device as claimed in any preceding claim wherein the at least one flow guide extends between a first axial end and a second axial end of a collar and comprises at least one flow guide surface extending in a fluid flow direction between forward and rearward ends and aligned oblique to a longitudinal axis of the device.

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