FIELD
This relates to a magnetic filter for a fluid port
BACKGROUND
In some fluid systems, such as hydraulic motor fluid systems, it is necessary to remove ferrous particles to prevent or reduce the damage to components in the fluid system. Magnetic filter elements have been designed to be introduced into the flow stream to help remove these ferrous particles. United States pre-grant publication no. 2011/0094956 (Marchand et al) entitled “Filter Elements” and U.S. Pat. No. 6,706,178 (Simonson) entitled “Magnetic Filter and Magnetic Filtering Assembly” are two examples of magnetic filter elements.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:
FIG. 1 is a side elevation view in section of a magnetic filter element.
FIG. 2 through 4 are side elevation views in section of magnetic filter elements with alternative attachments.
FIG. 5 through 7 are top plan views of magnetic filter elements without a top plate.
FIG. 8 is a top plan view of a top or bottom plate of a magnetic filter element.
FIG. 9 is a top plan view of an end cap for a magnetic filter element.
FIG. 10 is a side elevation view in section of a magnetic filter element in context of a retrofit of a conventional filter housing performed by replacing the media filter element.
FIG. 11 is a side elevation view in section of a magnetic filter element demonstrating the modular nature of the magnetic filter element. The dashed lines enclose a single modular filter segment.
FIG. 12 is a side elevation view in section of a magnetic filter element in a conventional filter housing used in series with a media filter.
FIG. 13 is a side elevation view in section of a magnetic filter element used in an inline application within a fluid pipe.
FIG. 14 through 16 are top plan views of a top or bottom plate of a magnetic filter element shown with various internal and external geometries.
FIG. 17 is a perspective view of a magnetic filter element.
DETAILED DESCRIPTION
Referring to FIG. 1, there is shown a magnetic filter 10, comprising a stack 12 of magnetic filter elements 14 having a central flow channel 16 through stack 12. Central flow channel 16 is made up of a series of flow openings 17 (shown in FIG. 5) in magnetic filter elements 14 that form the stack. The number of magnetic filter elements 14 and the number of flow openings 17 may vary. Magnetic filter 10 also has a series of flow gaps 18 between adjacent magnetic filter elements 14. As shown, central flow channel 16 is aligned with a flow port 20 of a fluid system, which may be considered an outer fluid environment relative to magnetic filter 10. For example, as shown, fluid port 20 is communicating with a fluid reservoir 22, and fluid may be flowing through fluid port 20 in either direction relative to fluid reservoir 22. In addition to the depicted fluid reservoir 22, magnetic filter 10 may be positioned within a pipe, for example, within an oversized section of pipe that allows fluid to flow between the outside and the inside of filter 10 as described below, without an undue restriction of flow. Filter 10 may also be installed in other areas where it is desired to filter a fluid flow.
Referring to FIGS. 1 and 2, each magnetic filter element 14 is made up of one or more magnets 24 enclosed within a non-magnetic housing 26 around the corresponding flow opening 17. Non-magnetic housing 26 isolates magnets 24 from the outer fluid environment, such that they do not come into contact with the fluid. In one example, housing 26 is made from a non-ferrous material, such as aluminium, stainless steel, etc. Other materials may also be used, including non-metals, as will be recognized by those skilled in the art. In the depicted example, housing 26 is made up of a top plate 28, a bottom plate 30, and a spacer element 32. Spacer element 32 may be inner and outer rings 34a and 34b as shown in FIGS. 5 and 7, where FIG. 5 shows round rings 34a and 34b while FIG. 7 shows profiled rings that accommodate the size of magnets 24. Alternatively, referring to FIG. 6, spacer element 32 may be a single component with cavities 36 shaped to receive magnets 24. Other variations will be apparent to those skilled in the art. For example, magnets 24 may be individually housed, rather than housed in a single element. Magnets 24 are designed to be the same height or smaller than spacer element 32, such that, when housing 26 is assembled, magnets 24 are enclosed and isolated within housing 26. It has been found that a thinner magnetic filter element 14 is preferable to a thicker filter element 14, with a higher surface area to volume ratio.
Referring to FIG. 8, the top plate 28 or bottom plate 30 of the magnetic filter element 14 making up housing 26 and defining flow opening 17 has apertures 44 through which pin connectors 46 are inserted. Referring to FIG. 14 through FIG. 16, it will be appreciated that the outer perimeter 50 and the inner perimeter 52 defining flow opening 17 may each have varying geometries to accommodate for different placements and needs, and that the geometries are not limited to those shown in the drawings, as many combinations of outer and inner perimeter geometries may be used.
It will be understood that various designs for housing 26 may be used. However, the versions of housing 26 depicted in the drawings have the benefit of being made from metal, and may be made using a die stamp and press. It will also be understood that the shape and number of magnets 24 may also have a bearing on the size and shape of spacer element 32, or housing 26 as a whole. In the depicted example, magnets 24 are rectangular prisms and multiple magnets 24 are used, and are equally spaced within housing 26 around flow opening 17. For example, there are eight magnets of equal size positioned within housing 26. As magnets can be formed in many different shapes and sizes, and may be curved, the actual configuration of housing 26 may be varied by those skilled in the art to suit the circumstances. It will also be understood that the polarity of magnets 24 may also vary, depending on the magnetic field that a user desires to apply to a flow stream.
Referring to FIGS. 1 and 9, an end cap 38 is positioned at the top of stack 12. As shown, end cap 38 is part of a filter element 14, where the top plate 28 has been replaced by a solid disk instead. This modified filter element 14 is placed at the top of stack 12 to force fluid flow to pass through flow gaps 18. By using a modified filter element, magnets 24 are placed above the adjacent flow gap 18. Alternatively, end plate 38 may not carry magnets. In that case, it may be preferable to make the adjacent flow gap smaller as there will be less of a magnetic field applied in that area.
Also referring to FIG. 1, an attachment 40 is also included at the bottom of stack 12. As with end cap 38, attachment 40 is preferably included as a component in a modified filter element 14. Attachment 40 is used to secure magnetic filter 10 in place. When installed in a ferrous tank, magnets 24 may also act as part of attachment 40 to hold magnetic filter 10 in place. Attachment 40 may have a central flange 42 that helps align magnetic filter 10 with flow port 20 and create a seal if necessary. The seal may not be a fluid tight seal, but should be sufficient to ensure that only a very small amount of seepage is permitted around magnetic filter 10 during use. Alternatively, some flow may be permitted around the bottom of magnetic filter 10, such that the space between the bottom filter element 14 and the reservoir wall 22 may be considered a flow gap 18 as well. In a further alternative, attachment 40 may be a cylindrical, threaded connection that screws into a fitting in fluid port 20, as shown in FIG. 2. In a further alternative, attachment 40 may be connected directly to fluid port 20, which may extend a certain distance into fluid reservoir 22, as shown in FIG. 3. In the depicted example, fluid port 20 is a pipe with a flange 43 that may have an O-ring seal 45. Other types of attachment may also be used. Fluid port 20 may extend in any direction, such as extending down or up into the fluid reservoir, or laterally. Referring to FIG. 4, in another alternative, stack 12 may be permanently installed in a container, such that it may be installed as an inline filter. In this example, attachment 40 may not be located at the bottom of stack 12, but may be attached at any convenient location.
FIG. 10 shows the use of stack 12 installed in a conventional filter housing 54. Magnetic filter elements 14 may be used to retrofit an existing media filter and applied to pre-existing filter housings 54 in a variety of contexts. In the depicted embodiment the filter housing 54 has a filter bowl 56, inlet 58, outlet 60, and drain port 62. The stack 12 of magnetic filter elements 14 is attached to a support spring 64. Magnetic filter 10 may also be applied in combination with a traditional media filter 66, as shown in FIG. 12. In this case the fluid being filtered passes through the magnetic filter 10 and then travels through the media filter 66, although it will be understood that these two filters could be used in any order. Magnetic filter 10 may also be applied in an inline pipe application, as shown in FIG. 13. In this case, the magnetic filter 10 is added into pipe 68 and the fluid flows through the stack 12 of magnetic filter elements 14 and then continues on the previous direction of flow through the pipe.
As shown, magnetic filter elements 14 have apertures 44 through which pin connectors 46 are inserted. Spacer elements 48 in the form of elongate cylinders may be placed over pin connectors 46 between filter elements 14 to create and maintain flow gaps 18. Spacer elements 46 are preferably larger than apertures 44 or otherwise maintained between elements 14. Alternatively, spacer elements 46 may be integrally formed with elements 14. As pin connectors 46 are tightened, pressure is increased on spacer elements 46 and filter elements 14, which acts to stabilize magnetic filter 10 and also seal housing 26. While housing 26 may also be closed and sealed using a different approach, using pin connectors 46 has the added benefit of reducing the number of steps to assemble and disassemble magnetic filter 10. While not shown, the height of spacer elements 48 may vary in order to change the size of flow gaps 18 in order to properly proportion the flow along filter element 10 and possibly increase the efficiency of magnetic filter 10. FIG. 17 shows an embodiment of magnetic filter elements 14 connected by pin connectors 46. It will be understood that the geometry and size of the elements in the magnetic filter 10 may vary as discussed previously.
The number of filter elements 14 in stack 12 may be varied according to the preferences of the user and the design constraints. FIG. 11 depicts an example of the modular nature of the magnetic filter elements 14, allowing for the number used to be varied. The dashed lines in FIG. 11 enclose a single modular filter segment 14 that can be stacked in stack 12. As the number of filter elements increases, the number of flow gaps 18 and therefore the flow cross-sectional area also increases. This increase in flow area results in a reduction of the average velocity and therefore an increase in the dwell time within filter 10. Preferably, the flow areas of gaps 18 and central flow channel 16 are each greater than the flow area of fluid port 20 to prevent any back pressure on the hydraulic system. As depicted in FIG. 1, attachment 40 has a portion that is fitted within fluid port 20. This reduction in flow area at this point may be avoided if necessary by using a different attachment design, or minimized to within an acceptable amount. In addition to increasing the number of filter elements 14 in stack 12, the flow area through gaps 18 may also be increased by increasing the diameter or width of filter elements 14. This may be preferable in situations where the allowable height is limited.
The flow of fluid will now be described with reference to the depicted embodiment in FIG. 1. As mentioned previously, filter 10 may be installed in other environments, although the principles of operation will be similar. Fluid may flow either from fluid port 20 into fluid reservoir 22, or from fluid reservoir 22 into fluid port 20. Magnetic filter 10 is designed to permit parallel flow of fluid through flow gaps 18 between fluid reservoir 22 and central flow channel 16, while end cap 38 prevents the direct flow of fluid along central flow channel 16 and out of filter 10. End cap 38 thus increases the turbulence, causes a change in direction of the fluid flow and enhances the filtering capabilities of filter elements 12. As fluid flows through gaps 18, magnets 24 will act upon the ferrous particles entrained within the flow to magnetically capture them and retain them against filter elements 14. Some magnetic filtering will also occur as fluid passes through central flow channel 16, however it can be seen that the magnetic field will be strongest within flow gaps 18.
In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.
The scope of the following claims should not be limited by the preferred embodiments set forth in the examples above and in the drawings, but should be given the broadest interpretation consistent with the description as a whole.
Patent Grant
9517473
