Abstract:
The present invention relates to a method for converting a full flow oil and/or fuel filter system into a bypass filter system comprising the use of a retro-fittable bypass filter configured to directly replace the pre-existing full flow filter, without the need for additional hoses or mounts etc. as in existing methods. Also described is a filter device for converting a full flow oil and/or fuel filter system into a bypass filter system comprising: an inlet for allowing fluid into the filter; a plurality of screens for filtering particles from the fluid; a cellulose element for filtering moisture from the fluid; an outlet for allowing fluid out of the filter; and a bypass for fluid to bypass the cellulose element and at least one screen and exit the filter, wherein the bypass filter is configured to directly replace the pre-existing full flow filter.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a bypass filter method and device. 
       BACKGROUND 
       [0002]    It is known that common spin-on oil and fuel filters used on all diesel and petrol engines result in accumulated moisture and particulate contamination. This depletes the engine oil additive package, including Total Base Number (TBN), resulting in undesirable sludge, varnish and accelerated oil oxidation. Also, fuel economy and emission standards prematurely deteriorate as the Original Equipment Manufacturers (OEM) design function of the fuel injection systems and piston rings become impaired. Hence, the engine oil is ‘spent’ at only 250-500 hours in a diesel engine and 10,000 miles in a car petrol engine. 
         [0003]    The primary issue with common spin-on oil filters is that they are full flow (70-185 litres per minute depending on the size of the engine) at approximately 80 psi. They only start filtering particulate at 30 to 40 μm and have no capacity to absorb or retain moisture. The technical issue with spin-on oil and fuel filters not retaining moisture in emulsion is that ‘the presence of wear metals alone can cause oxidation rates to increase to five (5) times the normal rate, while the presence of water can increase the oxidation rate ten (10) times. Combined, water and metal catalysts can increase the oxidation rate fifty (50) times or more’ (ref:  USA National Tribology ). From this, one learns that it is moisture contamination that accelerates oil oxidation ×10 and this critical issue was either not known, or was ignored in 1950&#39;s designed common spin-on oil and fuel filters that are still used today in all engines. 
         [0004]    Another type of filtering device is known as edge-on or depth filtration, used in bypass kidney loop oil filtration. These are known to be most effective, but are mainly sold in the aftermarket, where there is consumer resistance to fitting hose connections and unwarranted concerns about engine warranty. 
         [0005]    The present invention attempts to overcome at least in part some of the aforementioned disadvantages of previous filtering devices. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with one aspect of the present invention there is provided a method for converting a full flow oil and/or fuel filter system into a bypass filter system comprising the use of a retro-fittable bypass filter configured to directly replace the pre-existing full flow filter. 
         [0007]    The fluid which is not bypassed, may be so filtered at a rate of between 0.5 and 2 litres per minute. 
         [0008]    The fluid which is not bypassed, may be so filtered at a rate of 1.2 litres per minute 
         [0009]    The fluid which is not bypassed, may be so filtered at a pressure of between 0 and 10 psi. 
         [0010]    The fluid which is not bypassed, may be so filtered at a pressure of between 4 and 6 psi. 
         [0011]    In accordance with a second aspect of the present invention there is provided a retro-fittable bypass filter for converting a full flow oil and/or fuel filter system into a bypass filter system comprising: 
         [0012]    an inlet for allowing fluid into the filter; 
         [0013]    a plurality of screens for filtering particles from the fluid; 
         [0014]    a cellulose element for filtering moisture from the fluid; 
         [0015]    an outlet for allowing fluid out of the filter; and 
         [0016]    a bypass for fluid to bypass the cellulose element and at least one screen and exit the filter, 
         [0000]    wherein the filter is configured to directly replace a pre-existing full flow filter. 
         [0017]    The cellulose element may comprise a satchel of moisture-absorbing polymer. 
         [0018]    The filter may comprise a venturi effect between the outlet and the bypass. 
         [0019]    The filter may further comprise a restriction orifice for restricting the volume of fluid to be filtered rather than bypassed. 
         [0020]    The restriction orifice may have a diameter of between 1 and 20 mm. 
         [0021]    The restriction orifice may have a diameter of 2 mm when the fluid is oil; and a diameter of 9 mm when the fluid is fuel. 
         [0022]    The cellulose element may remove moisture from the fluid to a level of no more than 0.01 ppm. 
         [0023]    The fluid may comprise oil additive package and the filter may release any oil additive package that has encapsulated particulate matter captured by the filter, back into the fluid. 
         [0024]    At least one screen may comprise a woven mesh with apertures of a size slightly smaller than a diameter of the restriction orifice. 
         [0025]    At least one screen may comprise a pad with apertures of a size between 5 and 10 μm. 
         [0026]    At least one screen may be mounted on a screen support plate. 
         [0027]    The filter may further comprise an adapter plate complementary to an apparatus requiring filtration, for adapting the filter to be directly fittable to an existing oil or fuel filter mounting. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0028]    The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
           [0029]      FIG. 1  is a front (top of  FIG. 1 ) to back (bottom of  FIG. 1 ) section view of a filter in accordance with one embodiment of the present invention; 
           [0030]      FIG. 2  is a section view of a filter in accordance with a second embodiment of the present invention; 
           [0031]      FIG. 3  is a section view of the filter of  FIG. 2  with an attached adapter plate; 
           [0032]      FIG. 3 a    is a section view of a second embodiment of the adapter plate; 
           [0033]      FIG. 4  is a section view of a filter in accordance with a third embodiment of the present invention 
           [0034]      FIG. 5  is a section view of a filter in accordance with a fourth embodiment of the present invention; 
           [0035]      FIG. 5 a    is a detail view of a portion of the filter of  FIG. 5 ; and 
           [0036]      FIG. 5 b    is a detail view of another portion of the filter of  FIG. 5 . 
           [0037]      FIG. 6  is a plan view of a screen support plate of the filter of the present invention. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0038]    Referring to the Figures, there is shown a retro-fittable bypass filter  10  for converting a full flow oil and/or fuel filter system into a bypass filter system according to a preferred embodiment of the present invention. The filter  10  comprises a body  12  which acts to encase the internal parts of the filter  10 , which is substantially cylindrical in shape. With specific reference to  FIG. 2 , the body  12  of the filter  10  comprises a front face  14  forming a substantially circular cover for a majority of the front end of the filter  10 . The front face  14  is shaped so as to enable it to receive an annular seal  16 . It is preferred that the size, shape and configuration of the front face  14  and seal  16  is such that the filter  10  is complementary to connect to an oil and/or fuel reservoir on which it is used. 
         [0039]    The front face  14  comprises an inlet port  18  which includes at least one aperture that allows entry of oil or fuel to the internal portion of the filter  10 . The inlet port  18  opens to a filter screen  26 , after which is disposed both a restriction orifice  22  and a relief channel  48 . The restriction orifice  22  allows the flow of a controlled volume of fluid from the inlet port  18  to a cellulose filter element  28 . The orifice  22  is preferably about 2 mm or 9 mm in diameter and, in use, allows the passage of between about 0.5 and 2 litres of fluid per minute, preferably about 1.2 litres of fluid per minute. It has been advantageously found that the pressure of the fluid allowed through the restriction orifice  22 , and accordingly circulated through the filter  10  rather than being bypassed, is between about 0 and 10 psi, preferably between about 4 and 6 psi. 
         [0040]    Disposed after the inlet port  18 , prior to the restriction orifice  22  and relief channel  48 , is at least one filter screen  26 . The filter screen  26  preferably comprises a woven mesh pad comprising apertures of a size slightly smaller than the diameter of the restriction orifice  22 . The filter screen  26 , in use, removes large particles from the fluid being filtered and conglomerates particulate at the first side of the filter screen  26 . In this way, the filter screen  26  removes any large particles that would otherwise have the opportunity to block the restriction orifice  22 . 
         [0041]    The cellulose filter element  28  is disposed such that oil or fuel passes through the element  28  from the restriction orifice  22 . The cellulose filter element  28  may comprise a satchel of moisture-absorbing polymer, and filters particles, including substantially all moisture, from the oil or fuel which passes through it. The moisture filtered from the oil or fuel includes both heavy water and water in emulsion with the oil/fuel (sludge). Whilst removing contaminants from oil being filtered, it has been found that the present invention conserves the oil additive package, providing substantial benefits for the machinery on which it is used. It is preferred that the cellulose filter element  28  is in a coiled arrangement within the substantially cylindrical filter  10 . 
         [0042]    Disposed after the cellulose filter element  28 , according to the direction of fluid through the filter  10 , is a polishing screen  30  mounted on a screen support plate  54  (see  FIG. 6 ), such that the cellulose filter element  28  is disposed between the filter screen  26  and polishing screen  30 . The polishing screen  30  comprises a filter pad; preferably the filter pad of polishing screen  30  is substantially an absolute filter comprising apertures of a size between 5 and 10 μm. After the polishing screen  30  is a cavity  24 . Within the cavity  24  is an end of a supply channel  20  which comprises a channel inlet  46 . According to one embodiment of the present invention the supply channel  20  is formed as a channel substantially centrally within, and spanning the length of, the filter  10  (see  FIG. 2 ). 
         [0043]    With reference to  FIGS. 1 and 5 , alternative embodiments of the filter  10  of the present invention are shown, with like numbers referencing like parts to the second embodiment described above. As can be seen, all fluid enters the filter  10  at the inlet ports  18  to travel to the filter screen  26 , disposed distally to the inlet ports  18 . Again, the fluid passes through the filter screen  26  then to either the relief channel  48  or restriction orifice  22 . Accordingly, the relief channel  48  is disposed as the channel substantially centrally within, and spanning the length of, the filter  10 . As with previously described embodiments, fluid which is allowed through the restriction orifice  22  and is not bypassed, passes through the cellulose filter element  28 , followed by the polishing screen  30  to the cavity  24 . From the cavity  24 , the filtered fluid enters the supply channel  20  through the channel inlet  46  and exits the filter  10  to be provided to the engine oil gallery, for example. 
         [0044]    With reference to  FIG. 4 , a third embodiment of the filter  10  of the present invention is shown, with like numbers referencing like parts to the previously described embodiments. Again, fluid enters the filter through the inlet ports  18  and passes through the filter screen  26 . The majority of fluid then enters the relief channel  48  and exits the filter  10  though the relief outlet  40  and is subsequently “bypassed”. The minor volume of fluid allowed through the restriction orifice  22  is further filtered through firstly the cellulose filter element  28 , then through the polishing screen  30 . This “filtered” fluid then enters the supply channel  20  to exit the filter  10 . 
         [0045]    The relief channel  48  of the filter  10  provides a fluid connection between the inlet port  18  and a relief outlet  40  through which fluid which entered the inlet port  18  and relief channel  48  may return to the oil reservoir. It is preferred that the filter  10  comprises a venturi effect  52 , between the supply channel  20  and the relief channel  48 , as best seen in  FIG. 5 a   . The relief outlet  40  may comprise a threaded portion on the internal wall thereof (see  FIGS. 2, 3 and 5 ). As would be understood by the person skilled in the art, the threaded portion provides a connection by which the filter  10  may be threaded to and connect with the engine, for example, on which it is used. It is preferred that the relief outlet  40  and thread size is complementary to the part of the oil reservoir on which it is used. 
         [0046]    With reference to  FIGS. 3 and 3   a , the filter  10  may be provided with an adapter plate  70  for ease of attachment of the filter  10  to the engine etc. on which it is used. Accordingly, the adapter plate  70  comprises a front face  14  configured to be complimentary to the equipment to which it is retro-fitted. Hence, it has been found that a standard filter  10  may be provided with one of any number of adapter plates  70  such that the filter  10  may be used for various different engines etc. 
         [0047]    The adapter plate  70  comprises a filter thread  72  complimentary to the threaded portion on the relief outlet  40  of the filter  10 , thereby provided a connection between the filter  10  and the adapter plate  70 . The adapter plate  70  further comprises an adapter thread  74  suited to its connection point on the engine. The adapter thread  74  may be provided as either an internal thread as shown on  FIG. 3  or an external thread as shown on  FIG. 3 a   , according the configuration of the equipment requiring filtration. 
         [0048]    The axial flow of fluid through both pathways provided by the fuel filter  10  is represented with arrows on  FIGS. 2, 3 and 3   a . The restriction orifice  22  only allows the passage of a portion of fluid, so the remainder enters the relief channel  48  and returns to the engine through the relief outlet  40 . As would be understood, this ensures, for example, that the engine is not starved of oil while it passes through the filter  10 . 
         [0049]    The filter  10  may be constructed of any suitable material including metal or plastic by cutting or injection moulding, for example. It is also possible for the filter to be constructed of a composition of different materials, for example with the exterior constructed of plastic and the interior of metal. 
         [0050]    In use, the filter  10  may be threaded onto, or otherwise provided to, an engine or other part of a machine on which it is to be used either directly or indirectly, through the use of the adapter plate  70 . Preferably, the threaded portion of the relief outlet  40  is rotated onto a complementarily threaded portion of the engine. As would be understood, it is preferred that the size, shape and configuration of the filter  10  and threaded portion of the relief outlet  40  is complementary to the engine and thread on which it is used. 
         [0051]    Once fitted, the inlet port  18  can receive oil or fuel from the oil or fuel reservoir of the machinery on which it is used, or other source, as desired. Fluid is received through the inlet port  18 , past the front face  14  to the internal part of the filter  10 , specifically through the filter screen  26  to the restriction orifice  22  or relief channel  48 . As would be understood, only a controlled volume of fluid is permitted through the restriction orifice  22 . 
         [0052]    The fluid to the restriction orifice  22  has been forced, under the pressure in the filter system, through the filter screen  26 . As the filter screen  26  comprises mesh with apertures of a size no larger than 1.8 mm when the restriction orifice  22  is 2 mm, or no larger than 8.8 mm when the restriction orifice is 9 mm, particles larger than this size are separated from the fluid, which is allowed through the restriction orifice  22  into the cellulose filter element  28 . The cellulose filter element  28  allows the passage of oil or fuel but not moisture. Accordingly the cellulose filter element  28  removes substantially all moisture from the fluid being filtered. 
         [0053]    Upon exiting the cellulose filter element  28 , the fluid is forced through the polishing screen  30 . In a similar fashion to the fluid passing the filter screens  26 , as the polishing screen  30  comprises a pad with apertures of a size between 5 and 10 μm, particles larger than this size are separated from the fluid, said fluid passing through the polishing screen  30  to the cavity  24 . To ensure no blockages from build-up of particulate matter on the polishing screen  30 , at least one orifice  56  of a size about 2 mm or 9 mm is provided in the screen support plate  54 . Once filtered, the fluid from the cavity  24  enters the supply tube  20  through the tube inlet  46 . The fluid then travels the length of the supply tube  20  to exit the filter  10  and can be provided to the engine oil gallery. 
         [0054]    The remaining volume, being the bulk of oil/fuel entering though the inlet  18 , is not allowed passage to the restriction orifice  22 . Rather, the fluid travels through the filter screen  26 , via the relief channel  48  to exit the filter through the relief outlet  40 . Accordingly, the fluid not allowed though the restriction orifice  22  exits the filter  10  through the relief outlet  40  to be used by the engine or other part of the machinery as required. As would be understood, according to the equipment and the volume of the fluid reservoir on which the filter  10  is used, between about 70 and 185 litres per minute of fluid is bypassed. This bypass fluid travels through the filter screen  26 , for capture of large particles, then out of the filter  10  via the relief channel  48  through the relief outlet  40 . 
         [0055]    It has been found that the present invention provides advantages over existing filtration methods and devices including: operation of the entire diesel engine inventory on 1,000-3,000 hour extended oil and filter element change; significant reduction in the cost of repairs and maintenance on engines and hydraulic pumps; reduction in the cost of oil, filters and labour to service diesel engines by 70%; assured optimum engine performance, availability and extended lubricated component service life; significant reduction in cost and volume of waste oil disposal, and carbon foot print with a direct correlation between improved fuel economy and improved standard of emissions; maintenance of performance and significantly extended service of fuel pumps and injectors; achievement of engine and hydraulic ‘Least Whole of Life Cost’. 
         [0056]    Optimum filtration standard is achieved through this invention; the contaminants of particulate and water in emulsion are captured so the oil additive package including Total Base Number (TBN) is conserved. The relatively low flow rate and pressure allows the oil additive package to be released from around the particulate so additive package stripping is significantly reduced. This has been found to reduce pressure on oil additive package detergency and dispercency, to maintain the full OEM design function of the piston rings and injection system. Optimum engine performance, availability, significantly extended engine life, optimum fuel economy results as does a reduction in engine service operating expense including labour by 70%. 
         [0057]    As it is known that bypass kidney loop oil filtration can enable engines with low operating hours to operate on 2,000-3,000 extended hours oil change, this invention achieves this same extended hours in the same spin-on filter dimensions as the OEMs use. 
         [0058]    Other embodiment filters  10  are contemplated in accordance with the preferred embodiments of the present invention. For example, while it is preferred that the filter  10  is used to filter oil or diesel or other fuel for a motor, filtration of other fluids and use on other engines or equipment for filtration purposes are able to be performed with the filter  10  of the present invention. The oil and/or fuel reservoirs on which the filter  10  may be used include, but are not limited to, engines, oil sumps, dry sump systems, hydraulics and gear boxes. 
         [0059]    Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.