Patent Publication Number: US-2015068967-A1

Title: High adsorption chambered filter

Description:
The subject matter of the present disclosure relates generally to fluid filtration and, more particularly, to a filter block constructed so as to increase the surface area available for adsorption. 
     BACKGROUND OF THE INVENTION 
     Fluid filters are commonly constructed from a variety of filter media that may be used to provide for mechanical filtration that removes particulates over a certain size. Such filter media may include e.g., polymeric webs or fibers, woven or non-wovens, having a certain pore size that precludes the passage of particulates that are occluded from passing through the pores. One or more layers of filter media may be used. 
     Mechanical filtration, however, is not effective at removing certain substances such a volatile organic compounds (VOCs) or chlorine from fluids such as water. These substances can be present on a molecular size level. As such, they will pass readily through the pores or openings of a typical mechanical filter. Accordingly, some filters may include one or more substances for adsorption of contaminates from the fluid. For example, water filters may include activated carbon, which can remove components that are not captured by mechanical filtration. Substances such as VOCs are removed by adsorption onto the surface of the activated carbon. Depending upon the construction, a filter that includes activated carbon or other particles can also remove certain substances through mechanical filtration as well. 
     Conventional constructions typically rely upon extruded filter blocks of particles of adsorption media that are bound together to form the blocks. For example, activated carbon particles may be extruded in cylindrical shape with a low temperature polymeric binder material present to hold the particles together in the shape desired. While necessary to such construction, the binder significantly impacts the effectiveness and life of the filter block. Unfortunately, the binder will mask off or blind surface area on the particles of the adsorption media used to create the block. This surface area is needed for adsorption of contaminants such as VOCs. In general, the effectiveness of a block made from e.g., activated carbon particles is reduced proportionally as the amount of binder is increased. 
     Accordingly, there is a need for an adsorption based filter block for fluid filtering that is constructed with significantly less binder material. Such a filter block that can substantially improve the overall surface area of the block that is available for adsorption without substantially increasing the filter size is also needed. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention provides a filter block that uses a structure constructed from bound particles of an adsorption media that create one or more chambers for the receipt of unbound particles of the adsorption media. For example, the filter block may be constructed from activated carbon and binder and have one or more chambers containing unbound activated carbon. By using a structure formed of bound particles of the adsorption media having one or more chambers that contain unbound particles of the adsorption media, the surface area available for adsorption can be substantially increased relative to conventional configurations. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
     In one exemplary embodiment, the present invention provides a fluid filter that includes a filter block defining a longitudinal axis. The filter block has an external surface for the inflow of unfiltered fluid. The filter block defines at least one internal fluid passageway extending along the longitudinal axis and configured for the receipt of filtered fluid from the filter block and at least one chamber extending along the longitudinal axis and separated from the at least one internal passageway by the filter block. The filter block includes particles of an adsorption media and a binder that holds the particles together into a predetermined shape of the filter block. Unbound particles of the adsorption media are received into the at least one chamber and extend along the longitudinal axis. 
     In another exemplary embodiment, the present invention provides a fluid filtration device. The device includes a filter block having a body constructed from particles of an adsorption media held together by a binder. An external surface of the body provides for the ingress of fluid to be filtered. An internal fluid passageway within the body is separated from the external surface by the body. At least one chamber extends within the body and is separated from the at least one internal passageway by the filter block. Binder-free particles of the adsorption media are deposited within the at least one chamber. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  provides a perspective view of an exemplary embodiment of a fluid filtration device. 
         FIG. 2  illustrates a cross-sectional view of an exemplary embodiment of a filter block received within a filter housing as may be used with the exemplary filtration device of  FIG. 1 . 
         FIG. 3  is an exploded view of an exemplary embodiment of the filter block of  FIG. 2 . 
         FIG. 4  is a close up of an open end of an exemplary filter block showing the loading of unbound activated carbon into the chambers of the filter block. 
         FIGS. 5 ,  6 ,  7 , and  8  illustrate exemplary embodiments of filter blocks of the present invention. 
         FIG. 9  provides a plot of certain data as will be further described below. 
     
    
    
     The use of the same or similar reference numerals throughout the figures denotes the use of the same or similar features. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
       FIG. 1  provides a perspective view of an exemplary embodiment of a fluid filtration device  100  of the present invention, which may be used to filter e.g., potable water in residential or commercial applications. By way of example, fluid filtration device  100  might be installed under a kitchen sink to filter water supplied thereto or might be installed in the water supply line to an entire home. Other applications apply as well. Fluid filtration device  100  can provide for mechanical filtration of particulates from potable water. In addition, because fluid filtration device  100  uses activated carbon as will be further described, it can also remove VOCs, chlorine, and/or other substances by adsorption onto the activated carbon. 
     It should be understood, however, that the present invention is not limited to water filtration. Using the teachings disclosed herein, one of ordinary skill in the art will understand that the present invention may be used in other fluid filter applications including filtration of gases and/or other liquids. In addition, while activated carbon will be used herein as an example of the adsorption media that may be to used construct the filter block, other adsorption media (and combinations thereof) may be used as well for construction of the filter block. For example, activated carbon, sodium bicarbonate, titanium dioxide, ceramic materials, aluminosilicates, analcime, chabazite, clinoptilotie, heulandite, natrolite, and stilbite and others may be used separately or in combination as the adsorption media. 
     For the exemplary embodiment shown in  FIG. 1 , fluid filtration device  100  includes a filter housing  104  attached at end  106  to a filter manifold  102 . A variety of different configurations of inlet and outlet connections may be provided for the connection of filter manifold  102  to a water supply. Filter manifold  102  and housing  104  may be constructed e.g., from one or more molded plastics.  FIG. 1  provides an example of the appearance and configuration of filter housing  104  and filter manifold  102 . Other shapes and configurations having a different appearance may be used as well. 
     Referring now to  FIG. 2 , a filter block  110  is positioned within filter housing  104 . As such, filter block  110  can be replaced by disconnecting filter housing  104  from filter manifold  102  and replacing with a new filter housing containing a new filter block. Other embodiments of the invention, filter block  110  may be removably received within filter housing  104  so that only block  110  need be replaced. Other constructions may be used as well. By way of example, it may be necessary to replace filter block  110  once its activated carbon is substantially loaded through adsorption of one or more substances from the water being filtered. 
     Filter block  110  defines a longitudinal axis L extending along its length. As shown, during operation, unfiltered water is fed to fluid filtration device  100  and generally travels along longitudinal axis L in a first direction (arrows U) in filter housing  104 , inflows filter block  110  through its external surface  112 , and is filtered as it passes (arrows S) through filter block  110 . Having passed through filter block  110 , filtered water is received into an internal fluid passageway  114  defined by filter block  110 . Filtered water then generally flows in a second direction (arrows F) along the longitudinal axis L of filter block  110  and exits filter housing  104  and then filter manifold  102  for supply to e.g., a faucet, valve, or other water supply. It should be understood that the fluid flow path within filter manifold  102  and housing  104  described is provided by way of example only—others may be used as well. 
     An exploded view of the exemplary filter block  110  is provided in  FIG. 3 . A body  134  of filter block  110  is constructed from activated carbon particles  118  that are held together in a predetermined shape (e.g., cylindrical as shown in  FIG. 3 ) by a binder  120 . By way of example, binder  120  may be polymeric, ceramic, or fibrous material that holds together the carbon particles in the predetermined shape desired for the body  134  of filter block  110 . A variety of shapes may be used for filter block  110 . 
     Referring now to  FIGS. 3 and 4 , for this exemplary embodiment, filter block  110  defines a plurality of chambers  116  that are separated from internal fluid passageway  114  by the construction of body  134  as shown and extend along longitudinal axis L. Chambers  116  provide a space or volume into which unbound (i.e. binder-free) activated carbon particles  122  may be received or deposited as indicated by arrows P in  FIG. 4 . By way of example, activated carbon particles  122  can be packed or pressed into chambers  116 . In one exemplary embodiment of the invention, activated carbon particles having a nominal size in the range of about  25  microns to about  200  microns may be used. Other size ranges may be used as well. 
     As stated, activated carbon particles  122  that are placed in chambers  116  defined by filter block  110  do not contain binder that would otherwise block or bind some of the surface area of the particles and thereby reduce ability of the particles  122  to provide filtration through adsorption. For example, depending on the amount of binder, activated carbon particle size, binder size and compression of carbon particles, binder can displace carbon particles at roughly a 1:1 ratio and partially blind off the existing surface area of the carbon particles by roughly the percentage of binder being used. A filter block constructed with e.g., 45% binder will have only 75% (100% −(55% percentage of carbon particles in the block)×(45% amount of surface area being blinded off by the binder particles)) of the available surface area as that of a block of the same volumetric, porous nature with no binder. Thus, having a filter block  110  that provides significant amounts of activated carbon particles  120  that do not contain binder can greatly improve the overall surface area available for adsorption. 
     By comparison, the body  134  of filter block  110  is constructed with binder  120  to hold its activated carbon particles  118  into the desired shape. However, by carefully controlling the amount of binder  120  used, only a portion of the activated carbon particles  118  comprising filter block  110  will be bound or otherwise unavailable for adsorption. As such, as compared to a conventional filter block of the same size that uses e.g., non-activated carbon materials to construct the body of the filter block, the overall surface area of activated carbon available for adsorption using filter block  110  is significantly increased. For example, in one exemplary embodiment, body  134  of filter block  110  includes binder in a range of about 30 percent or less of the total weight of body  134  (before depositing unbound activated carbon present in chambers  116 ). In still another exemplary embodiment, body  134  of filter block  110  includes binder in a range of about 25 percent or less of the total weight of body  134  (before depositing unbound activated carbon present in chambers  116 ). 
       FIG. 9  provides a plot of certain data to further illustrate these concepts. Line  140  represents a 10 cubic inch, standard carbon block filter constructed with activated carbon particles held together by binder. As the amount of binder content increases (shown as a weight percent of the total weight of the carbon block), the percent of surface area available for adsorption decreases (the vertical line at 45 percent represents the typical binder content found in conventional filter blocks constructed of activated carbon. 
     Line  138  represents a conventional, 10 cubic inch, filter block constructed from a porous ceramic structure with honeycomb-shaped chambers that contain unbound activated carbon particles (i.e. binder free). Because no binder is present, the surface area available for adsorption remains constant and can provide significantly more surface area relative to filter block represented by line  140  as the amount of binder for line  140  increases. 
     Line  136  represents a 10 cubic inch filter block constructed e.g., according to an exemplary embodiment of the present invention where the body of the filter block is constructed from activated carbon bound together in a predetermined shape and forming honeycomb-shaped chambers filled with binder-free activated carbon. As shown, the filter block of line  136  has almost 46 percent more surface area available for adsorption that the filter block of line  140  and about 19 percent more surface area than the filter block of line  138 . 
     Returning to  FIGS. 2 ,  3 , and  4 , filter block  110  extends along longitudinal axis L between a first end  124  and a second end  126 . First end  124  defines a plurality of openings  128  to chambers  116  through which non-bound, activated carbon particles may be deposited into chambers  116 . A first cap  130  is attached to first end  124  and a second cap  132  is attached to second end  126 . Caps  130  and  132  help ensure that the flow of unfiltered water is through external surface  112  of filter block  110 . 
     As shown in  FIG. 4 , for this exemplary embodiment, filter block  110  is constructed with a plurality of uniformly spaced chambers  116  positioned around internal fluid passageway  114  and separated therefrom by the body  134  of filter block  110 . In addition, along a cross-section orthogonal to the longitudinal axis L, chambers  116  appear to be square in shape. However, a variety of other shapes and configurations for filter block  110  may be used. 
     For example,  FIG. 5  illustrates another exemplary embodiment of filter block  110  having single chamber  116  formed as an annulus by body  134 . As with the previous embodiments, body  134  is formed from activated carbon particles held together by binder  120  in the shape desired. Unbound, or binder-free, activated carbon particles can be placed into chamber  116 . 
       FIG. 6  illustrates another exemplary embodiment of filter block  110  having a plurality of chambers  116  as well as a plurality of internal fluid passageways  114 .  FIG. 7  illustrates still another exemplary embodiment of filter block  110  having a plurality of chambers  116  of a different shape from previous embodiments and including a single, internal fluid passageway  114 . Finally,  FIG. 8  illustrates still another exemplary embodiment of filter block  110  having a plurality of chambers  116  and a single internal fluid passageway  114 . For this exemplary embodiment, chambers  116  have a hexagonal shape in a cross-section that is orthogonal to the longitudinal axis L. The density and number of chambers  116  can be increased to provide still another embodiment with a honeycomb shape in cross-section. Other configurations and shapes other than what is shown in the figures may be used as well. 
     Returning to  FIG. 5 , in still another exemplary embodiment of the present invention, body  134  could be formed from e.g., a media such as paper or a fiber based media. Such media could be impregnated with adsorption media. Fluid passageway  114  can still be formed from adsorption media held together by binder while chamber  116  is filled with unbound adsorption media. As such, this construction can be used to further reduce the amount of binder present in filter block  110 . 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.