Abstract:
A filter for separating contaminants from fluids. The filter includes stages of differing materials arranged one after another wherein the first stage blocks and captures contaminants of a selected size and passes everything smaller than this selected size. The next stage captures contaminants of a selected size which is smaller than those blocked by the first stage. The subsequent stages capture smaller and smaller contaminants. The layers comprise various materials including stranded meshes, fibrous tissues, metallic screens and ceramic discs and tubes. Some of the ceramic discs and tubes include a downstream coating to capture further contaminants such as water droplets.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Patent Application No. 61/958,040 filed on Jul. 18, 2013 and is a Continuation in Part of U.S. application Ser. No. 13/985,441 filed on May 2, 2013, both of which are incorporated by reference herein in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to the field of filters used to eliminate contaminants from liquids. 
       BACKGROUND OF THE INVENTION 
       [0003]    Systems which involve liquid flow are frequently are plagued with blockages and restrictions caused by foreign contaminants. Because liquid systems cannot remain contaminant free, a liquid filtering system is always required. Contaminants within a fluid/liquid system exist due to many factors. The simple process of assembling and handling the fluid system parts and components often introduces undesirable contaminants. The act of turning a threaded pipe or fitting into a mating component often shears off thread burrs, allowing the burrs to flow through the liquid system. Small pieces of weld slag, grains from the foundry or cast core sand may be involved. Foreign matter may be deposited during storage of replacement piping and then released during assembly. Component wear and tear will introduce contaminants into the system. Contaminants may be introduced along with the desired fluids when fluid is added to the system. For these and many more reasons, a liquid system requires that a filtering system be in place and maintained. 
         [0004]    The ideal liquid filtering system will remove all foreign contaminants from the liquid without impeding fluid flow through the system as demanded by the pump. Other desirable characteristics include: low cost, high capacity, small size and easy maintainability. There are three main types of filtration systems: mechanical, adsorbent, and absorbent. Typical liquid processing systems include some combination of these three types of filter. 
         [0005]    Mechanical filters are probably the most common in industrial liquid systems. The liquid is forced by pressure through the filter element. The filter is composed of micro-openings, pores or tortuous passages that block and capture larger sizes particles. This type of filter, commonly referred to as a surface type filter, is normally composed of woven fabric, metallic or synthetic screens and/or absorbent paper or paper like materials. The constituent parts of such filters must be compatible with the process liquid and with the expected contaminants. Fire resistance (as applicable), resistance to collapse (due to pressure differential), and compatibility with system temperature are other important issues to consider in choosing a filter. Filters may be constructed of pleated stainless steel, Monel wire and synthetic woven materials. 
         [0006]    Adsorbent filters are typically include porous materials such as cotton, paper, wood, cloth, asbestos, etc. Adsorption is a process wherein contaminants adhere to the surface or surfaces of a filter member rather that being trapped within a filter member. In general this type filter is used to filter fine soluble&#39;s and may be designed to allow selected dirty liquid through relatively thick layers with an increase in compactness of the filter material in the direction of flow. 
         [0007]    Absorbent filters function by absorbing and trapping contaminants within a filter member. Examples of absorbent filter material include fuller&#39;s earth, boneback, ceramic, graphite, grapheme, charcoal, activated carbon, activated clay, copper, silver, platinum, gold, or other metals or metal compounds, chelating agents, or chemically treated organic mediums applicable to the filtration of oil, fuel, syngas, natural gas or other petroleum or alcohol based products. This type of liquid filtering system may be in the form of gravity feed bed or even a cartridge type installation. This system presents a large surface area through which the liquid flows. The insoluble oxidation products and solid contaminants are removed by size filtration and absorption. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with the present invention, there is provided a multistage filter capable of filtering contaminants from a liquid flowing under pressure into said multistage filter, said multistage filter comprising, consisting of , or consisting essentially of an outer cylindrical shell having a first end sealed, a second end containing a central outlet port and at least one inlet port near a peripheral edge thereof. The cylindrical shell contains at least two concentric cylindrical filter media. The ends of the two cylindrically shaped media are fluidly sealed against the inner surfaces of the first sealed end and the second end of the cylindrical shell. The at least one inlet port is in fluid communication with the outer surface of the first outer cylindrical stage. The central outlet port is in fluid communication with the inner surface of the innermost one of the at least two concentric cylindrically shaped filter media. The innermost one of said at least two concentric cylindrically shaped filter media comprising ceramic and including a filter coating on an inner surface thereof. 
         [0009]    It is an object of this invention to provide a multistage canister filter which includes a plurality of stages or layers of filtering material of differing porosities. 
         [0010]    It is an object of this invention to provide a multistage canister filter wherein all of the incoming liquid is forced through the first and then subsequent stages so that no amount of the incoming liquid is allowed to bypass any one stage of the multistage filter. 
         [0011]    It is an object of this invention to provide a multistage canister filter wherein the first stage blocks contaminants of the largest size and allows the liquid and the smaller contaminants to pass to the next stage, the next stage traps the next largest size contaminants and so on and so on until the liquid is acceptably free of all undesirable contaminants. 
         [0012]    It is an object of this invention to provide a multistage canister filter wherein all of the filter stages include one or more of the following elements: metallic or synthetic mesh type screen, stranded meshes, fibrous tissues, paper and/or paper-like materials, metallic screens, ceramic discs and ceramic tubes. 
         [0013]    It is an object of this invention to provide a multistage canister filter wherein the final stage includes a cylindrical ceramic filter media where the inner surface of the ceramic includes a coating which further catches selected contaminants which are able to pass through the ceramic filter media. 
         [0014]    It is an object of the present invention to provide filters or coatings on filters which function as chelating agents which chemically react with selected compounds. 
         [0015]    It is another object of the present invention to provide filter material or filter coated material which adsorbs selected molecules of a particular compound due to ionic attraction or molecular size. 
         [0016]    It is another object of the present invention to provide filter material which can adsorbed by activated charcoal or coat a charcoal or ceramic material which is reacts with and combines to hold selected chemical compounds. 
         [0017]    Other objects, features, and advantages of the invention will be apparent with the following detailed description taken in conjunction with the accompanying drawings showing a preferred embodiment of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like numerals refer to like parts throughout the views wherein: 
           [0019]      FIG. 1  is a cross-sectional view of a multistage canister filter showing the various filter elements. 
           [0020]      FIG. 2  is an end view of a multistage canister filter showing the central outlet port and the plurality of outer inlet ports. 
           [0021]      FIG. 3  is a perspective end view of the multistage canister filter. 
           [0022]      FIG. 4  is perspective view of a liquid handling system including a pump. 
           [0023]      FIG. 5  is perspective view of a cylindrical screen filter medium. 
           [0024]      FIG. 6  is perspective view of a cylindrical ceramic filter medium with a Zeolite inner coating. 
           [0025]      FIG. 7  is perspective view of a disc shaped ceramic filter medium with a Zeolite inner coating. 
           [0026]      FIG. 8  is a front view of an example of woven material such as a screen filter. 
           [0027]      FIG. 9  is a front view of an example of material woven by ‘Dutch weave’. 
           [0028]      FIG. 10  is front view of an example of material woven by ‘double Dutch weave’. 
           [0029]      FIG. 11  is a cross-sectional view of another embodiment of the multistage filter. 
           [0030]      FIG. 12  is a top view of a linear multistage cylindrical filter. 
           [0031]      FIG. 13  is a top view of selected inner components linear multistage cylindrical filter. 
           [0032]      FIG. 14  is a top view of other selected inner components linear multistage cylindrical filter. 
           [0033]      FIG. 15  is a top view of other selected inner components linear multistage cylindrical filter. 
           [0034]      FIG. 16  is a bottom view of the linear multistage cylindrical filter. 
           [0035]      FIG. 17  is a front view of a screw on filter housing and a filter element. 
           [0036]      FIG. 18  is a front view of a filter housing installed. 
           [0037]      FIG. 19  is a front view of a base for receiving and holding a filter element and a screw on filter housing. 
           [0038]      FIG. 20  is a cylindrical filter with an inlet port at one end and an outlet port at the other. 
           [0039]      FIG. 21  is a group of disc shaped filter media portions aligned as if in a cylindrical housing. 
           [0040]      FIG. 22  is a group of cylindrical, spherical, or disc shaped activated charcoal pellets coated with a selected oxide. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    In accordance with the present invention, there is provided a multistage filter for removing contaminants from selected liquids such as fuels and oils. The multistage filter  10  shown in  FIG. 3  is cylindrical with a sealed end  9  and a ported end  8  including multiple inlet ports  30  near the outer edges and one outlet port  32  in the center of ported end  8 . The ported end  8  includes an outer O-ring or flat ring  34  and an inner O-ring or flat ring  36 . The ported end  8  of the multistage filter  10  is held firmly against the flat mating surface  56  of a liquid handling unit  50  which includes a pump. The liquid handling unit  50  includes and at least one outlet port  54  and a central inlet port  52 . The O-rings  34  and  36  are thus held tightly against the flat mating surface  56  and form a sealed connection between the filter  10  and the liquid handling unit  50 . The filter  10  is situated against the mating surface so that the outlet port or ports  54  of the liquid handling unit  50  are fluidly connected between O-ring  34  and O-ring  36  and therefore, liquid pumped out of outlet ports  52  would be forced through the inlet ports  30  of filter  10 . It follows then that the inlet port  52  of liquid handling unit  50  receives liquid from the outlet port  32  of filter  10 . 
         [0042]      FIG. 1  shows a cross-sectional view of filter  10  which includes several concentric cylindrical stages. The area  13  between the outer shell  12  and the first stage  14  of filter  10  is the area into which the inlet ports  30  feed liquid under pressure from the pump in liquid handling unit  50 . 
         [0043]    It is understood that the filter  10  is cylindrical and contains concentric cylindrical filter stages of various selected filtering capabilities. It is further understood that all of the concentric cylindrical stages are tightly held against or are firmly and sealingly connected to the ported end  8  and the sealed end  9  of the filter  10  so that no amount of fluid may leak past any one stage of the filter. The first stage includes a screen  14  which catches contaminants of a selected size and passes everything which is smaller. The second stage is a cylindrical filter material  16  which catches contaminants of a next smaller selected size and passes everything which is yet smaller. The third stage  18  is a second cylindrical filter material which will catch contaminants of a next smaller selected size which are small enough to get through the first stage  14  and the second stage  16  but will pass contaminants which are yet smaller in size. The fourth stage  20  is a third cylindrical filter material which will catch contaminants of yet a next smaller selected size which are small enough to get through the first stage  14 , the second stage  16  and the third stage  18 , but will pass contaminants which are yet smaller in size. The final stage  22  is a cylindrical ceramic finer sized to catch contaminants of yet a next smaller selected size which are small enough to get through the first stage  14 , the second stage  16 , the third stage  18 , and the fourth stage  20 , but will pass contaminants which are yet smaller in size. 
         [0044]    It is therefore understood that filter  10  contains multiple stages of varying filtering capabilities and that the first stage catches large sized contaminants and each subsequent stage catches contaminants of a next smaller size. This configuration is the most efficient configuration of filter elements. If the order of the elements was reversed with the first element catching everything including the smallest sized contaminants, no contaminants would ever proceed to the next stages and more importantly, the first stage would become clogged quickly. 
         [0045]    The following is a list of various filter materials with varying filtering capabilities described in terms of the size of particles which will be trapped by the material given in microns or millions of a meter: 
       List of Filter Media 
       [0000]    
       
         1 Envirostran poly flow material 40 to 60 micron used—beginning FST-26, 63, RF-6, 4, &amp; 8 
         2 Envirostran poly flow material 15 to 25 micron used—middle RF-8 
         3 Envirostran poly flow material 5 to 10 micron used before ceramics FST-26, 63, RF-6, 4, &amp; 8 
         4 Poly flow material 8 micron 
         5 Poly flow material 5 micron 
         6 Matt finish combination poly flow material with weave design 8 to 10 micron 
         7 Matt finish weave combination poly flow material with weave design 2 to 5 micron 
         8 SS, copper, aluminum, or iron pads used to remove particulate, sulfur, and other unwanted chemicals 
         9 SS wire cloth 30 micron single weave, or can be double dutch weave 
         10 SS wire cloth 10 micron single weave, or can be double dutch weave 
         11 Double weave, matt finish poly flow material 8 micron 
         12 Ceramics from 2 to 15 microns 
         13 Metallic screens 40 to 100 microns 
         14 Zeolite coating 1 micron (captures water) 
         15 Film membranes filtering to the molecular level 
       
     
         [0061]    Filtering coatings other than Zeolite include cationic coatings but do not include catalytic coatings. Film membranes are used as filter media. Ultrafiltration is a variety of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. This separation process is used in industry and research for purifying and concentrating macromolecular (10 3 -10 6  Daltons or unified atomic mass units) solutions, especially protein solutions. Ultrafiltration is not fundamentally different from microfiltration except in terms of the size of the molecules it retains. Microfiltration is a membrane technical filtration process which removes contaminants from a fluid (liquid &amp; gas) by passage through a microporous membrane. A typical microfiltration membrane pore size range is 0.1 to 10 micrometres (μm). Microfiltration is fundamentally different from reverse osmosis and nanofiltration because those systems use pressure as a means of forcing water to go from low pressure to high pressure. Microfiltration can use a pressurized system but it does not need to include pressure. 
         [0062]    Numbers 9 and 10 in the above list refer to a ‘double dutch’ weave. A dutch weave, shown in  FIG. 9 , is a wire mesh or filter cloth with warp wires larger than the weft wires. (Warp refers to the vertical wires  42  and weft refers to the horizontal wires  44  in the mesh as shown in  FIG. 8  which is a plain weave.) As shown in  FIG. 9 , warp wires remain straight while adjacent weft wires slightly overlap, resulting in a dense, strong material with small irregular, twisting passages that appear triangular in shape when viewing the material diagonally. Double dutch weave, shown in  FIG. 10 , is a dutch weave where the weft wires alternately weave through alternate pairs of warp wires. Dutch weaves have much lower flow rates and much higher particle retention than plain square weaves. 
         [0063]    Preferred embodiments of the present invention include a final stage which is a ceramic element. Certain preferred embodiments include a ceramic filter  40 , as shown in  FIG. 6 , which has an inner coating  42  of a material such as Zeolite, which filters even smaller contaminants than the ceramic medium  40 . A Zeolite coating is capable of blocking contaminants, such as droplets of water, down to 1 micron in size. Zeolite in powder form (either man made or natural) it can be coated to the inside or outside of any of the filtration media. This is excellent for removing water droplets at the 1 micron level. One downside is the filter cartridge has to be vacuum sealed until it is installed due to the moisture in the air. 
         [0064]    Preferred embodiments of the multistage filter of the present invention therefore include from two to ten filtering stages or more wherein the filtering stages are concentric cylindrical elements where the outer stages contain filter material which catch larger particles than the next inner stages. An example of such a preferred embodiment includes:
   a first stage which is a metallic screen which passes 75 micron contaminants;   a second stage which is Envirostran poly flow material which passes 50 micron contaminants;   a third stage which is Envirostran poly flow material which passes 10 micron contaminants;   a fourth stage which is a matt finish weave combination poly flow material which passes 5 micron contaminants; and a ceramic element which passes 3 micron contaminants.   
 
         [0069]    Another embodiment of the present invention is a linear filter  70 , shown in  FIGS. 11-16 . The shell  72  of the filter body in the figures is cylindrical but may be cubic, rectangular, or ovoid. The stages of the filter  70  are stacked linearly, one above the other rather than concentric cylinders. The flow is in at the top  61  and out the bottom  69 . The first stage is a plastic screen  74  with nine apertures  75 . The second stage is a metallic screen  76  of 100 micron mesh. The third stage is a Envirostran poly flow material  78  with 60 micron filtering. The fourth stage is a Envirostran poly flow material  80  with 30 micron filtering. The fifth stage is a ceramic disc  82  with 10 micron filtering. An O-ring  84  of Buna N rubber separates the ceramic disc  82  from the sixth stage which is a metallic screen  86  and a bottom cover  88  including an output aperture  90 . 
         [0070]    Typically filters of the present invention include a cylindrical housing with filter elements inside arranged in stages or layers and wherein the fluid or gas to be filtered enters through an input port and exits through an output port. The layers are arranged in order so that the larger sized contaminants are blocked in the first encountered layers and progressively smaller contaminants are filtered in subsequent layers as the fluid or gas moves toward the output port. Input and output ports are located either on the filter housing ends as in  FIG. 20  or on the filter housing side as in  FIGS. 18 and 19 . For example, the filter housing  62  in  FIGS. 17-19  includes a filter element  63 , a screw-on lid  64 , an input port  65  and an output port  66 . Another example shown in  FIG. 20  has input  112  on one end and output  114  at the opposite end of the housing  110 . 
         [0071]    The layers or stages of filter elements are shaped and arranged in two different ways. The first arrangement has filter media layers which are cylindrical in shape as seen in  FIGS. 1 ,  5 , and  6  and are therefore arranged concentrically as shown if  FIG. 1  so that the flow of fluid or gas is preferably from the outer cylindrical layer  12  through consecutive cylindrical layers  14 - 22  to the output port  32 . The other preferred arrangement and shape of filter layers as shown in  FIGS. 20 and 21  contains disc shaped filter layers  90 - 100 , for example. The number of layers in either arrangement is only limited by the relative sizes and thicknesses of the layers and the size of the filter housing. 
         [0072]    Filter  110  in  FIG. 20  contains the layers  90 - 100  in  FIG. 21  contain media selected from the list of filter media above or other media. Other examples of filter media are shown in  FIGS. 22 and 23 . Cylindrical or pill shaped pellets  120  or spherical pellets  122  include an activated charcoal substrate coated or impregnated with aluminum oxide or copper oxide. These pellets are from one to ten millimeters in length or smaller. Aluminum oxide or copper oxide coated pellets are ideal for trapping sulfur impurities in natural gas or LPG. One embodiment of the present invention is a filter  110  with disc shaped elements  90  through  100  wherein element  90  is filled with aluminum oxide coated pellets  120  or with copper oxide coated pellets  122 . 
         [0073]    The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modification will become obvious to those skilled in the art upon reading this disclosure and may be made upon departing from the spirit of the invention and scope of the appended claims. Accordingly, this invention is not intended to be limited by the specific exemplification presented herein above. Rather, what is intended to be covered is within the spirit and scope of the appended claims.