Abstract:
A fuel filter/dryer having a casing, and the casing having an inlet and an outlet. At least a portion of the casing is filled with a desiccant through which the fuel flows. Also within the casing, is a particulate filter which removes harmful particles from the fuel. The desiccant is of a type that changes color when saturated with water. The casing is transparent to allow the change in color to be viewed in order to ascertain whether or not the fuel filter/dryer needs replacement.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to fuel filter/dryer for incorporation in the fuel system supplying a fuel consuming device such as an engine, heater, burner, furnace, etc.  
           [0003]    2. Description of the Prior Art  
           [0004]    Fuel systems in almost all motor vehicles, incorporate at least one particulate filter to filter out fine particles from the fuel flowing through the fuel system. Such fine particles could have disastrous consequences for the operation of the engines in motor vehicles because they can potentially obstruct the narrow passages in fuel injectors and/or carburetors; and if these particles do find their way into the engine, they can cause unnecessary wear and damage to engine parts. In addition to being contaminated by particulate matter, commercially sold fuel is also contaminated with water. This water presents a problem especially in winter time, because it can lead to fuel line freeze-up. Fuel additives are currently available on the market, which are added directly to the fuel in the fuel tank in order to “dry” the fuel. These additives however get consumed along with the fuel, and may adversely affect the performance of the engine and or shorten engine life. The present invention combines a particulate filter with a desiccant that remains separate from the fuel. Therefore, the present invention provides the benefits of removing particulate matter and water from the fuel, without adversely affecting the performance obtained from the fuel. None of the prior art shows the combination of a fuel filter and a bed of granular desiccant material in a single unit. Further, none of the prior art shows the system of baffles and mesh screens used in the present invention.  
           [0005]    U.S. Pat. No. 2,536,274, issued to Richard S. Gaugler Jan. 2, 1951, shows a desiccant cartridge for use refrigeration equipment. The desiccant cartridge of Gaugler made of desiccant granules contained in a woven mesh sleeve Gaugler does not show the combination of a fuel filter and desiccant bed in a single unit  
           [0006]    U.S. Pat. No. 3,029,581, issued to Hugh C. Robbins on 20 Apr. 17, 1962, shows a desiccant cartridge having an inner tube located concentrically within an outer tube. The desiccant housed in the inner tube and is held in place by wads of glass-wool referred to as filter discs. The desiccant cartridge of Robbins is intended for drying gases. Robbins does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Robbins does not show the system of baffles and mesh screens used in the present invention.  
           [0007]    U.S. Pat. No. 3,246,758, issued to William Wagner on 5 Apr. 19, 1966, shows a plug with a viewing window and a chemical moisture indicator used for determining the moisture content of a desiccant material. Wagner does not show the combination of a fuel filter and a desiccant bed in a single unit.  
           [0008]    U.S. Pat. No. 3,505,783, issued to Harold E. Graham on 10 Apr. 14, 1970, shows a transparent cylindrical housing containing an “adsorbent” material. Graham does not show the combination of a fuel filter and a desiccant bed in a single unit.  
           [0009]    U.S. Pat. No. 3,705,480, issued to Wallace M. Wireman on Dec. 12, 1972, shows a desiccant cartridge having a filter in series with a color-changing desiccant bed. The desiccant cartridge of Wireman is intended for drying gases. Wireman does not show the combination of a liquid fuel filter and a desiccant bed in a single unit. Further, Wireman does not show the system of baffles and mesh screens used in the present invention.  
           [0010]    U.S. Pat. No. 3,724,177, issued to George A. Grote on Apr. 3, 1973, shows a cartridge for filtering gases. The cartridge of Grote includes a bed of pulverulent material positioned between layers of cotton. Grote does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Grote does not show the system of baffles and mesh screens used in the present invention.  
           [0011]    U.S. Pat. No. 4,236,902, issued to Roy A. Fricke on Dec. 2, 1980, shows an air purifying apparatus having a filter and a bed of absorber material. The absorber material of Fricke is intended to remove pollution such as tobacco smoke from the air and is not a drying agent. Fricke does not show the combination of a fuel filter and a desiccant bed in a single unit.  
           [0012]    U.S. Pat. No. 4,259,097, issued to Amrut R. Patel et al. 10 on Mar. 31, 1981, shows an oil and desiccant filter for a gas. Patel et al. do not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Patel et al. do not show the system of baffles and mesh screens used in the present invention.  
           [0013]    U.S. Pat. No. 4,746,338, issued to Clifford C. B. Williams on May 24, 1988, shows a gas filter having a first section which contains a desiccant and a second section which contains activated charcoal. Williams does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Williams does not show the system of baffles and mesh screens used in the present invention.  
           [0014]    U.S. Pat. No. 4,853,123, issued to Mark B. Hays et al. on Aug. 1, 1989, shows a fuel filter having micron sized pores that filter out aqueous and particulate contaminants. Hays et al. do not show the combination of a fuel filter and a desiccant bed in a single unit Further, Hays et al. do not show the system of baffles and mesh screens used in the present invention.  
           [0015]    U.S. Pat. No. 5,017,285, issued to Leon P. Janik et al. on May 21, 1991, shows a fuel filter having a two stage filter, with the second stage acting as a water barrier. The trapped water is collected in a sump. Janik et al. do not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Janik et al. do not show the system of baffles and mesh screens used in the present invention.  
           [0016]    U.S. Pat. No. 5,879,543, issued to Bijan Amini on Mar. 9, 1999, shows a filter element composed of non-metallic material and water sensor used to detect presence of water in the fuel, which generates a signal that engages a pump to remove a quantity of separated water from the filter housing. Amini does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Amini does not show the system of baffles and mesh screens used in the present invention.  
           [0017]    U.S. Pat. No. 5,916,442, issued to David Paul Goodrich on Jun. 29, 1999, shows a fuel filter assembly for removing water from a fuel under pressure with a filter media positioned within sleeve members. An accumulation chamber and an outer valve provide the ability to drain unwanted fluid from the fuel. Goodrich does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Goodrich does not show the system of baffles and mesh screens used in the present invention.  
           [0018]    U.S. Pat. No. 5,993,675, issued to Albert P. Hagerthy on Nov. 30, 1999, shows a filter for separating water from fuel in marine and diesel engines. The filter elements are constructed from multiple adjacent microfibers layers bonded to each other which allows the passage of fuel while substantially limiting the passage of water. Hagerthy does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Hagerthy does not show the system of baffles and mesh screens used in the present invention.  
           [0019]    U.S. Pat. No. 6,224,439, issued to Sato, et al. On May 1, 2001, shows a fuel filter having a water accumulation detection ability. The water detecting mechanism is placed under the filter body made of transparent material. Sato at al. Do not show the combination of a fuel filter and desiccant bed in a single unit. Further, Sato et al. do not show the system of baffles and mesh screens used in the present invention.  
           [0020]    European Patent Application Number 0 162 022 A2, by Maria Cristina Cantoni dated Nov. 21, 1985, shows an air filter for automotive air conditioning units. Cantoni does not show the combination of a fuel filter and a desiccant bed in a single unit.  
           [0021]    United Kingdom Patent Document Number 343,105, by Richard Lant et al. dated Mar. 12, 1931, is directed to the use of higher fatty acid esters of cellulose as a filter material for removing water from organic liquids. Lant et al. do not show the combination of a fuel filter and a desiccant bed in a single unit.  
           [0022]    United Kingdom Patent Document Number 971,230, by Hugh C. Robbins dated Sep. 30, 1964, shows a cylindrical canister containing a desiccant material. Robbins &#39;230 does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Robbins &#39;230 does not show the system of baffles and mesh screens used in the present invention.  
           [0023]    United Kingdom Patent Application Number 2 030 886 A, by Eric John Hayward dated Apr. 16, 1980, shows a filter canister for holding a granular medium for the absorption of carbon dioxide during anaesthesia. Hayward does not show the combination of a fuel filter and a desiccant bed in a single unit.  
           [0024]    United Kingdom Patent Application Number 2 035 833, by Vaclav Sebor dated Jun. 25, 1980, shows a filter apparatus including a glass fiber filter element and a silica gel or activated carbon absorber, for filtering gases. Sebor does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Sebor does not show the system of baffles and mesh screens used in the present invention.  
           [0025]    United Kingdom Patent Application Number 2 080 697 A, by Barry W. Dinius dated Feb. 10, 1982, shows a filter/dehydrator including water absorbing cellulosic fibers in series with a filter element. Dinius does not show the combination of a fuel filter and a desiccant bed in a single unit. Further, Dinius does not show the system of baffles and mesh screens used in the present invention. None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.  
         SUMMARY OF THE INVENTION  
         [0026]    The present invention is directed to a fuel filter/dryer having a casing, and the casing having an inlet and an outlet. At least a portion of the casing is filled with a desiccant through which the fuel flows. Also within the casing, is a particulate filter which removes harmful particles from the fuel. The desiccant is of a type that changes color when saturated with water. The casing is transparent to allow the change in color to be viewed in order to ascertain whether or not the fuel filter/dryer needs replacement.  
           [0027]    Accordingly, it is a principal object of the invention to provide a combined fuel filter and dehydrator for use in fuel systems.  
           [0028]    It is another object of the invention to provide a combined  15  fuel filter and dehydrator having a desiccant which remains separate from the fuel.  
           [0029]    It is a further object of the invention to provide a combined filter/dehydrator having a color-changing desiccant so that a user can readily ascertain, by inspection, whether or not the filter/dehydrator needs replacement.  
           [0030]    Still another object of the invention is to provide a combined filter/dehydrator having a transparent casing.  
           [0031]    It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
           [0032]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]    [0033]FIG. 1 is a perspective view of the filter/dryer of the present invention partially broken away to reveal internal detail.  
         [0034]    [0034]FIG. 2 is a cross sectional view of the filter/dryer of the present invention showing the path of fuel flow through the filter/dryer.  
         [0035]    [0035]FIG. 3 is a schematic view showing the filter/dryer of the  15  present invention incorporated into an automotive fuel system.  
         [0036]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0037]    Referring to FIGS. 1 and 2, the present invention is directed  20  to a fuel filter/dryer cartridge  10 , also referred to herein as a filter/dehydrator. The cartridge  10  includes a substantially boxlike casing  12  having an inlet conduit  14  and an outlet conduit  16 . The casing  12  has an open top which is sealed by a lid  18 . The lid  18  can be permanently fixed in place for a disposable cartridge, or be detachable for a rebuildable cartridge. In both cases, the lid  18  must provide an air-tight closure for the open top of casing  12 . The lid can be sealingly fixed over the open top of casing  12  by any well known means including using an adhesive to fix the lid  18  in place, heat pressing lid  18  in place, and clamping the lid  18  in place.  
         [0038]    The box-like casing  12  is formed by five walls, a front wall  20 , a back wall  22 , a left wall  24 , a right wall  26 , and a bottom wall  28 . The inlet conduit  14  is centrally located in the back wall  22 , while the outlet conduit  16  is centrally located in the front wall  20 . The hollow bores of the inlet conduit  14  and the outlet conduit  16  are in communication with the interior of the casing  12 .  
         [0039]    Down stream of the inlet conduit  14  is a first baffle  30 . The baffle  30  sealingly abuts the lid  18 , the left wall  24 , and the right wall  26 . The baffle  30  extends, as a sheet, from the lid  18  and terminates at an edge  32 . The edge  32  is spaced apart from the bottom  28 . The baffle  30  can be molded in one piece with the casing  12 , or it can be fixed to walls  24  and  26  using adhesives or heat fusion. The top edge of the baffle  30  must be sealed against the lid  18  to ensure that all flow through the cartridge  10  passes between the bottom edge  32  of the baffle  30  and the bottom wall  28 . The top edge of the baffle  30  can be sealed against the lid using any well known means including adhesives, sealants, sealing strips, or heat fusion.  
         [0040]    Down stream of the baffle  30  is a second baffle  34  baffle  34  sealingly abuts the bottom  28 , the left wall  24 , and the right wall  26 . The baffle  34  extends, as a sheet, from the bottom  28  and terminates at a top edge  36 . The edge  36  is spaced apart from the lid  18 . The baffle  34  can be molded in one piece with the casing  12 , or it can be fixed to wall  24 , wall  26 , and bottom  28  using adhesives or heat fusion. All flow through the cartridge  10  passes between the top edge  36  of the baffle  34  and the lid  18 .  
         [0041]    The baffles  30  and  34  direct the flow of fuel, flowing through the cartridge  10 , through a bed of desiccant  38 . The desiccant is a granular solid, preferably calcium sulfate (CaSO4). The calcium sulfate removes water from the fuel flowing through the cartridge  10 . Fine wire mesh screens  40 ,  42 , and  44  confine desiccant granules within a well defined region of the casing  12 , and are used to prevent the desiccant granules from being dislodged by the force of the fuel flowing through the granules. Also mesh screens  40 ,  42 , and  44  keep the desiccant granules tightly packed so that the formation of empty channels through desiccant bed is avoided, thus ensuring intimate contact between the fuel and the desiccant granules.  
         [0042]    The mesh screen  40  extends across the flow area defined by the wall  24 , the wall  26 , the back wall  22 , and the baffle  30 . The mesh screen  42  extends across the flow area defined by the wall  24 , the wall  26 , the baffle  34 , and the baffle  30 . The mesh screen  44  extends across the open top of a trough  46  formed in the bottom  28 . The trough  46  is positioned under the desiccant bed  38 , extending along the full width of the cartridge  10 , and is intended as a  10  short-term repository for water once the desiccant becomes saturated with water.  
         [0043]    Positioned intermediate the baffle  34  and the outlet conduit  16 , is a particulate filter  48 . The filter  48  extends across the flow area defined by the lid  18 , the bottom  28 , the wall  26 , and the wall  24  such that all flow through the casing  12  must pass through the filter  48 . The filter  48  can be of any well known type and is intended to filter out fine particles from the fuel flowing through the cartridge  10 . Such fine particles could have detrimental effects in the apparatuses, such as an engine, in which the fuel is used. In the illustrated example, the filter  48  is composed of a corrugated paper filter element  50  sandwiched between two supporting mesh screens  52  and  54  (see FIG. 1). After passing through the filter  48 , clean, dry fuel then flows to the outlet conduit  16 .  
         [0044]    Referring to FIG. 3, the filter/dryer cartridge  10  is seen incorporated into an automotive fuel system. The fuel system includes a fuel tank  56 , the filter/dryer cartridge  10 , a fuel pump  58 , and an engine  60 . The filter/dryer cartridge  10  is spliced into the fuel line (not shown) between the fuel tank  56  and the fuel pump  58 . In this arrangement therefore, a first portion of the fuel line will provide for fluid communication between the fuel tank  56  and the inlet conduit  14 , while a second portion of the fuel line will provide for fluid communication between the outlet conduit  16  and the fuel pump  58 .  
         [0045]    The calcium sulfate desiccant  38  changes color, turning from white to blue, as it becomes saturated with water. Once all the desiccant changes color, the desiccant is completely saturated and is no longer effective in removing water from the fuel; therefore necessitating the replacement of the cartridge  10 . The casing  12  is made of a transparent plastic so that the change in color of the desiccant will be readily visible. Therefore, it can be easily determined, by mere inspection, whether or not it is time to replace the filter/dryer cartridge  10 . It should be noted that the present invention is not intended to be limited to having calcium sulfate as the desiccant, and that many other desiccant materials are also suitable for use in the present invention. In addition, the desiccant used in the present invention may be a composition including a desiccant material and a color-changing moisture indicator.  
         [0046]    It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.