Abstract:
A water filter assembly for a beverage dispenser. The water filter assembly may generally include a one-way valve disposed in the filter housing to allow air and water to escape so that the filter cartridge may be completely saturated. The one-way valve prevents air and water from entering the filter housing from the reservoir, thereby maintaining a vacuum that prevents the water level in the filter housing from dropping along with the water level of the reservoir. Furthermore, a protective screen is placed upstream of the one-way valve to prevent the sealing surface of the valve from becoming contaminated with debris or other sediment. In this manner, the one-way valve may maintain proper sealing performance throughout the lifetime of the filter.

Description:
FIELD OF THE INVENTION 
       [0001]    The subject matter of the present disclosure relates generally to a water filter assembly, or more specifically, to a water filter assembly having a one-way valve protected by a valve screen. 
       BACKGROUND OF THE INVENTION 
       [0002]    Water filter assemblies are commonly used with a variety of consumer and commercial appliances to remove dirt, sediment, and other contaminants from unfiltered water sources such as, for example, municipal water supplies. These water filter systems typically receive unfiltered water through a filter inlet, filter the unfiltered water by passing it through filter media to remove contaminants and debris, and pass the filtered water out through a filter outlet to the appliance for end use. 
         [0003]    For example, single serve beverage dispensers (SSBDs), including coffee maker appliances, utilize water for brewing and mixing operations. In order to provide single-serve beverages, SSBDs generally dispense small volumes of liquid (e.g., between eight and sixteen ounces) for each beverage. To permit consecutive preparation of beverages and decrease preparation time, certain SSBDs commonly include a removable water storage reservoir holding enough water to dispense between four and eight single-serve beverages. It is generally desirable to ensure that water stored in the reservoir is free from contaminants and other debris. Certain water filter assemblies include a filter cartridge having filter media, such as an activated carbon block, that is placed over a fluid outlet within the reservoir to filter contaminants from the water within the reservoir. 
         [0004]    Common filter cartridges have a one-way valve that allows air trapped inside the filter housing to escape when the filter cartridge is submerged, thereby allowing the filter housing to fill completely with water. During operation of a SSBD, it is important to maintain the water level in the filter housing, even as the water level in the reservoir decreases. If the water level in the filter housing is not maintained, the SSBD may dispense less than the requested volume of water because, for example, air may be pulled into the system which prevents the correct amount of water from being dispensed. 
         [0005]    In order to ensure that the filter housing remains full of water even when the water level in the reservoir decreases, the one-way valve acts as a seal to create a vacuum and prevent water from flowing out of the filter housing back into the reservoir. In this manner, the water level in the filter housing may be maintained even as the water level in the reservoir decreases. 
         [0006]    However, as water and air from the unfiltered water chamber exit the filter housing through the one-way valve, debris and contaminants may be deposited on the valve sealing surface, thereby compromising the effectiveness of the seal. When the seal created by the one-way valve is broken, air or water may enter the filter housing through the one-way valve, thus breaking the vacuum and allowing water to flow out of the filter housing as the reservoir water level drops. As a result, the SSBD may dispense less than the requested volume of water and the filter cartridge must be replaced or repaired. 
         [0007]    Accordingly, a water filter assembly that maintains the water level in the filter housing throughout the lifetime of the filter cartridge would be useful. More particularly, a water filter assembly having a one-way valve that may operate effectively for the life of a filter cartridge would be especially beneficial. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    Additional aspects and advantages of the invention will be set forth in part in the following description, may be apparent from the description, or may be learned through practice of the invention. 
         [0009]    In general, the present invention provides a water filter assembly for a beverage dispenser. The water filter assembly may generally include a one-way valve disposed in the filter housing to allow air and water to escape so that the filter cartridge may be completely saturated. The one-way valve prevents air and water from entering the filter housing from the reservoir, thereby maintaining a vacuum that prevents the water level in the filter housing from dropping along with the water level of the reservoir. Furthermore, a protective screen is placed upstream of the one-way valve to prevent the sealing surface of the valve from becoming contaminated with debris of other sediment. In this manner, the one-way valve may maintain proper sealing performance throughout the lifetime of the filter. 
         [0010]    In one exemplary embodiment, a water filter assembly for a beverage dispenser having a reservoir is provided. The water filter assembly defines an axial direction and a radial direction and includes a filter medium extending along the axial direction and defining an interior filtered water chamber, the filter medium configured to filter water flowing inward generally along the radial direction into the interior filtered water chamber. The water filter assembly further includes a housing extending along the axial direction between a first end and a second end and enclosing the filter medium, the housing and the filter medium defining an unfiltered water chamber between the housing and the filter medium. The housing further defines an inlet in flow communication with the unfiltered water chamber proximate to the second end for receipt of unfiltered water from the reservoir, and a housing outlet in flow communication with the interior filtered water chamber of the filter medium. The housing is configured to provide filtered water to a reservoir outlet. A housing cap is positioned at the first end of the housing and defines a channel fluidly connecting the unfiltered water chamber to the reservoir. A one-way valve is positioned within the channel, the one-way valve being configured to prevent fluid flow from the reservoir to the unfiltered water chamber. A valve screen is positioned between the one-way valve and the unfiltered water chamber, the valve screen being configured to filter unfiltered water passing from the unfiltered water chamber through the one-way valve to the reservoir. 
         [0011]    In another exemplary embodiment, a beverage dispenser is provided. The beverage dispenser includes a dispenser; a hot water chamber for providing the dispenser with heated water; a reservoir; and a water filter assembly. The reservoir defines a reservoir outlet and includes a fitting attached to the reservoir and at least partially surrounding the reservoir outlet, the reservoir outlet being fluidly connected to the hot water chamber for providing water to the hot water chamber. The water filter assembly defines an axial direction and a radial direction and includes a filter medium extending along the axial direction and defining an interior filtered water chamber, the filter medium configured to filter water flowing inward generally along the radial direction into the interior filtered water chamber. The water filter assembly also includes a housing extending along the axial direction between a first end and a second end and enclosing the filter medium, the housing and the filter medium defining an unfiltered water chamber between the housing and the filter medium, the housing additionally defining an inlet in flow communication with the unfiltered water chamber proximate to the second end for receipt of unfiltered water from the reservoir, the housing further defining a housing outlet in flow communication with the interior filtered water chamber of the filter medium, the housing configured to provide filtered water to the reservoir outlet. The water filter assembly also includes a housing cap positioned at the first end of the housing and defining a vent channel fluidly connecting the unfiltered water chamber to the reservoir. The water filter assembly also includes a valve assembly positioned adjacent the vent channel, the valve assembly including a check valve being configured to prevent fluid flow from the reservoir to the unfiltered water chamber and a valve screen positioned between the check valve and the unfiltered water chamber to filter unfiltered water passing from the unfiltered water chamber through the valve assembly to the reservoir. 
         [0012]    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 
         [0013]    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. 
           [0014]      FIG. 1  provides a front, perspective view of a beverage dispenser according to an exemplary embodiment of the present subject matter. 
           [0015]      FIG. 2  provides a schematic diagram of a portion of the exemplary beverage dispenser of  FIG. 1 . 
           [0016]      FIG. 3  provides a perspective view of a water filter assembly in accordance with an exemplary embodiment of the present disclosure. 
           [0017]      FIG. 4  provides a cross-sectional view of the exemplary water filter assembly of  FIG. 3 . 
           [0018]      FIG. 5  provides a close up, perspective view of a housing cap of the exemplary water filter assembly of  FIG. 3 . 
           [0019]      FIG. 6  provides a cross-sectional view of the housing cap of the exemplary water filter assembly of  FIG. 3  taken along Line  6 - 6  of  FIG. 5 , with the filter media removed for clarity. 
           [0020]      FIG. 7  provides a perspective cross-sectional view of the housing cap of the exemplary water filter assembly of  FIG. 3  taken along Line  6 - 6  of  FIG. 5 , with the filter media removed for clarity. 
           [0021]      FIG. 8A  provides a perspective view of a valve screen assembly according to an exemplary embodiment of the present disclosure. 
           [0022]      FIG. 8B  provides another perspective view of the exemplary valve screen assembly of  FIG. 8A . 
           [0023]      FIG. 8C  provides a cross-sectional view of the exemplary valve screen assembly of  FIG. 8A  taken along Line  8 C- 8 C of  FIG. 8A . 
           [0024]      FIG. 9A  provides a perspective view of a one-way valve with an integral valve screen according to an exemplary embodiment of the present disclosure. 
           [0025]      FIG. 9B  provides a cross-sectional view of the exemplary one-way valve of  FIG. 9A  taken along Line  9 B- 9 B of  FIG. 9A . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    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. 
         [0027]      FIG. 1  provides a front, perspective view of a beverage dispenser  100  according to an exemplary embodiment of the present subject matter. Beverage dispenser  100  is generally referred to as a “single serve beverage dispenser  100 ” and receives capsules or pods with flavorings therein that are brewed or mixed with hot or cold water to provide a hot or cold beverage, as desired. As an example, beverage dispenser  100  may be a KEURIG® brand single-cup coffee brewing system or a VERISMO™ brand single-cup coffee brewing system. However, beverage dispenser  100  may alternatively be any other suitable beverage dispenser. 
         [0028]    As may be seen in  FIG. 1 , beverage dispenser  100  includes a body  102 , a dispenser portion  104 , a pan or tray  106 , and a reservoir  108 . A lever  110  is provided with dispenser portion  104  to allow a user to open a lid  112  of dispenser portion  104  and access a receptacle (not shown) for receiving a capsule or pod. During brewing or mixing operations, water may be taken from the reservoir  108 , heated or cooled, and provided to dispenser portion  104 , wherein dispenser portion  104  either brews or mixes the water with the contents of the capsule or pod to provide a desired beverage. The beverage may be dispensed into a cup or mug (not shown) placed on tray  106  by a user. The exemplary beverage dispenser  100  also includes a control panel  114  including a display  116  and a plurality of user inputs  118  allowing the user to control operation of beverage dispenser  100 . 
         [0029]    It should be appreciated, however, that the present disclosure is not limited to any specific beverage dispenser  100 , and in other exemplary embodiments, beverage dispenser  100  may have any other suitable configuration. Indeed, the water filter assembly described below may be used in any appliance where fluid from a supply source must be filtered prior to use. 
         [0030]    As will be explained in greater detail below, and as is depicted in phantom in  FIG. 1 , a water filter assembly  120  is positioned in reservoir  108  and attached to a fitting  122  of reservoir  108 . Water filter assembly  120  is generally provided to remove contaminants and particles in the water in reservoir  108  through, e.g., mechanical filtration and/or absorption of such contaminants. 
         [0031]    Referring now to  FIG. 2 , a schematic diagram is provided of a portion of the exemplary beverage dispenser  100  of  FIG. 1 . As is depicted, beverage dispenser  100  further includes a hot water chamber  124  and a pump  128 . Hot water chamber  124  is configured to provide dispenser portion  104  with heated water via a conduit  126 . Additionally, pump  128  is in flow communication with reservoir  108  and is configured to provide a flow of water from the reservoir  108  to the hot water chamber  124  when activated. Pump  128  may be a centrifugal pump, or alternatively may be any other suitable pump. 
         [0032]    A priming vent  130  is provided in flow communication with the pump  128  and the reservoir  108  for providing a flow of water from the pump  128  to the reservoir  108  during a priming operation of the pump  128 . More particularly, priming vent  130  is provided to allow a pump head (not shown) of the pump  128  to flood with water during priming operations. 
         [0033]    Moreover, as schematically depicted, water filter assembly  120  is positioned in reservoir  108  and attached to fitting  122  in reservoir  108 . More particularly, reservoir  108  defines an outlet  132  fluidly connected to hot water chamber  124  via pump  128  for providing water to the hot water chamber  124 . During operation of the beverage dispenser  100 , pump  128  may pull water from reservoir  108 , through water filter assembly  120 , and provide such water to the hot water chamber  124 . Water from the hot water chamber  124  may then be provided to dispenser portion  104 , wherein such water may be brewed or mixed with contents of any capsules or pods positioned therein. As previously discussed, the desired beverage may then be dispensed via dispenser portion  104  to a user. 
         [0034]    During operation, if a pressure drop across water filter assembly  120  is greater than a certain threshold, fluid may be pulled from priming vent  130  as opposed to reservoir  108 . The fluid may initially be water, however, it may also include air. If such fluid is allowed to be so pulled from priming vent  130  to pump  128  such that air is provided to pump  128 , the air may cause pump  128  to cavitate and not operate properly. Accordingly, in certain exemplary embodiments of the present disclosure, beverage dispenser  100  may further include a one-way valve  133  positioned in priming vent  130  for preventing a flow of fluid in a flow direction away from reservoir  108  through priming vent towards pump  128 . One-way valve  133  may have any suitable configuration. Inclusion of one-way valve  133  may allow for proper operation of beverage dispenser  100 , or more particularly proper operation of pump  128 , regardless of a pressure drop across water filter assembly  120  greater than a certain threshold. 
         [0035]    Referring now to  FIGS. 3 and 4 , water filter assembly  120  is illustrated in accordance with an exemplary embodiment of the present disclosure. More particularly,  FIG. 3  provides a perspective view of water filter assembly  120  in accordance with an exemplary embodiment of the present disclosure, and  FIG. 4  provides a cross-sectional view of the exemplary water filter assembly  120  of  FIG. 3 . As best shown in  FIG. 4 , water filter assembly  120  defines an axial direction A and a radial direction R. In certain embodiments, the axial direction A of water filter assembly  120  may be aligned with a vertical direction, however in other embodiments, water filter assembly  120  may be aligned in any other suitable orientation. 
         [0036]    Water filter assembly  120  includes a filter medium  134  extending along the axial direction A between a first end  136  and a second end  138 —filter medium  134  defining interior filtered water chamber  140 . For the embodiment depicted, filter medium  134  is a cylindrical filter medium configured to filter water flowing inward generally along the radial direction R. Filter medium may be an activated carbon block, a pleated polymer sheet, a spun cord material, a melt blown material, one or more layers of fine mesh, or any other material suitable for filtering contaminants from a flow of fluid. According to the illustrated embodiment, filter medium  134  is, for example, an activated carbon block shaped in the form of a hollow cylinder. However, in other embodiments, filter medium  134  may be formed of any other suitable material. 
         [0037]    Filter medium  134  is enclosed by a housing  142  also extending along the axial direction A between a first end  144  and a second end  146 . More particularly, filter medium  134  is enclosed by a body portion  148  of housing  142  defining a generally cylindrical shape extending along the axial direction A. First end  144  of housing  142  is positioned proximate to first end  136  of filter medium  134  and second end  146  of housing  142  is positioned proximate to second end  138  of filter medium  134 . Housing  142  and filter medium  134  together define an unfiltered water chamber  150  between the housing  142  and filter medium  134 . For the embodiment depicted, the unfiltered water chamber  150  includes a generally annular chamber between body portion  148  and filter medium  134 , as well as a volume above filter medium  134  at first end  144  of housing  142  and first end  136  of filter medium  134 . 
         [0038]    Body portion  148  of housing  142  additionally defines one or more inlets  154  proximate to second end  146  of housing  142  for receipt of unfiltered water from, e.g., reservoir  108 . More particularly, housing  142  defines a channel  152 , with the inlets  154  defined at an end of the channel  152  proximate to second end  146  of housing  142 . Inlets  154  may provide flow communication between reservoir  108  and unfiltered water chamber  150 . In this manner, unfiltered water may flow into housing  142  from reservoir  108  through inlets  154  and may fill the entire unfiltered water chamber  150 . 
         [0039]    In alternative embodiments, housing  142  may further include a siphon tube that extends from a location proximate to second end  146  of housing  142  to a location proximate first end  144  of housing  142  to provide unfiltered water to the unfiltered water chamber  150  at a location proximate to first end  144  of housing  142 . Such a configuration may allow for a relatively high-performance filtering of water in reservoir  108  while minimizing a pressure drop across water filter assembly  120 . More particularly, with such a configuration, unfiltered water is provided to first end  136  of filter medium  134  and may saturate substantially all of a surface area of filter medium  134  by filling unfiltered water chamber  150  from a top end. 
         [0040]    Although the above-described embodiments describe inlets  154  positioned proximate second end  146 , one skilled in the art will appreciate that other configurations may use any number of inlets positioned anywhere on housing  142 . Indeed, inlets may be configured in any manner suitable for filling unfiltered water chamber  150  with fluid. 
         [0041]    Referring specifically to  FIG. 4 , a first filter cap  158  is positioned over first end  136  of filter medium  134  to cover interior filtered water chamber  140  of filter medium  134 . First filter cap  158  may be attached to first end  136  of filter medium  134  in any suitable manner. For example, first filter cap  158  may be attached to first end  136  of filter medium  134  using a glue or other suitable epoxy. Notably, first filter cap  158  may seal interior filtered water chamber  140  from unfiltered water chamber  150  at first end  136  of filter medium  134 . Accordingly, unfiltered water provided to unfiltered water chamber  150  must flow inwardly along the radial direction R through filter medium  134  to reach interior filtered water chamber  140 . 
         [0042]    Housing  142  further includes a housing cap  160  positioned at first end  144  of housing  142  covering body portion  148  of housing  142 . In certain embodiments, housing cap  160  may be attached to body portion  148  of water filter assembly  120  using an interference fit and/or a spin welding attachment method. However, in other embodiments, housing cap  160  may be attached to body portion  148  using any other suitable attachment means or mechanism to form a hermetic seal. Alternatively, in still other embodiments one or more portions of housing cap  160  may be formed integrally with body portion  148 . 
         [0043]    Water filter assembly  120  further includes a second filter cap  162  positioned at second end  138  of filter medium  134 . Second filter cap  162  is configured for sealing second end  138  of filter medium  134  to housing  142 . More particularly, second filter cap  162  includes a flange  164  extending outwardly along the radial direction R. Similarly, second end  146  of housing  142  includes a corresponding flange  166  extending inwardly along the radial direction R. Flange  164  of second filter cap  162  is positioned between the second end  146  of filter medium  134  and flange  166  of second end  138  of housing  142 . 
         [0044]    In certain embodiments, flange  164  of second filter cap  162  may be attached to second end  138  of filter medium  134  and/or flange  166  of second end  146  of housing  142  using a glue or any other suitable epoxy. Additionally, or alternatively, flange  164  of second filter cap  162  may be attached to second end  138  of filter medium  134  and/or flange  166  of second end  146  of housing  142  by applying a grease. Moreover, it should be appreciated, that in still other embodiments, flange  164  of second filter cap  162  may be attached to second end  138  of filter medium  134  and/or flange  166  of second end  146  of housing  142  in any other suitable manner, or alternatively may not be attached and instead one or more of the various components may be sealed by designing water filter assembly  120  with relatively close tolerances. 
         [0045]    Referring now particularly to  FIG. 4 , housing cap  160  may include one or more one-way valves to control the flow of fluids between reservoir  108 , unfiltered water chamber  150 , and interior filtered water chamber  140 . During certain events, air may make its way into one or both of interior filtered water chamber  140  and unfiltered water chamber  150 . For example, air may be present in one or both of interior filtered water chamber  140  and unfiltered water chamber  150  when water filter assembly  120  is first installed in reservoir  108  or when the water level in reservoir  108  decreases. However, to ensure proper operation of beverage dispenser  100 , it is generally beneficial for interior filtered water chamber  140  and unfiltered water chamber  150  to be completely filled with water. 
         [0046]    Accordingly, first filter cap  158  may include a one-way valve  180  allowing air and fluid from interior filtered water chamber  140  to flow into unfiltered water chamber  150 . For the embodiment depicted, one-way valve  180  is configured as a ball check valve. More specifically, one-way valve  180  includes an inverse frustoconical opening with a bottom hole defined adjacent to interior filtered water chamber  140  and a top hole positioned adjacent to unfiltered water chamber  150 . A ball  182  is positioned in one-way valve  180  and is configured to cover the bottom hole to prevent fluid from traveling from unfiltered water chamber  150  to interior filtered water chamber  140 . Additionally, ball  182  is configured to move upwards in response to a pressure differential greater than a predetermined amount across one-way valve  180 —i.e., when a pressure in interior filtered water chamber  140  is more than a predetermined amount greater than a pressure in unfiltered water chamber  150 —such that fluid may flow around ball  182  and into unfiltered water chamber  150 . 
         [0047]    Notably, ball  182  is not biased towards resting against the bottom hole (i.e., a closed position) other than by any force on ball  182  exerted by gravity. The predetermined amount of pressure differential for ball  182  to move up in certain exemplary embodiments may accordingly be relatively low. For example, in certain embodiments, ball  182  may be configured to move upwards when the pressure differential is less than or equal to one inch of water pressure. Additionally, for the embodiment depicted, ball  182  may be formed of a non-buoyant elastomeric material. However, in other exemplary embodiments, ball  182  may be formed of any other suitable material and the pressure differential may be any other suitable pressure differential. 
         [0048]    In general, one-way valve  180  assists in evacuating air trapped in filtered water chamber  140 , e.g., when it is first installed in reservoir  108 . One-way valve  180  may be particularly beneficial when air becomes trapped inside interior filtered water chamber  140  after the filter medium  134  is wetted, e.g., when water filter assembly  120  is installed, removed, and reinserted into reservoir  108 , or after the reservoir  108  is emptied. When this occurs, air trapped inside interior filtered water chamber  140  may not evacuate completely because a wet filter medium  134  provides more flow resistance than a dry filter medium  134 . 
         [0049]    As is also depicted in  FIG. 4  housing cap  160  may similarly include a one-way valve  184  (details not shown) that is configured in substantially the same manner as one-way valve  180  in first filter cap  158 . In this manner, one-way valve  184  allows air and fluid to travel from unfiltered water chamber  150  to reservoir  108 , but prevents air or water from entering unfiltered water chamber  150  from reservoir  108  through housing cap  160 . Therefore, as water filter assembly  120  is submerged, water may fill the entire unfiltered water chamber  150  and interior filtered water chamber  140 , thereby displacing all air within housing  160 , which may be evacuated through one-way valve  184 . Then, one-way valve  184  acts as a seal to provide suction and prevent housing  160  from draining as the water level in reservoir  108  is lowered. Therefore, the water level may drop all the way to inlet  154  positioned near the bottom of reservoir  108 , but the water filter assembly  120  remains substantially filled with water. 
         [0050]    By filling the entire unfiltered water chamber  150  with water, substantially all of the surface area of filter medium  134  may be utilized, and a pressure drop across water filter assembly  120  may remain within an acceptable limit of beverage dispenser  100 . Moreover, such a configuration provides for utilization of substantially all of the surface area of filter medium  134  regardless of a water level in reservoir  108 . Accordingly, substantially all of the surface area of filter medium  134  may be utilized even when a water level in reservoir  108  is below first end  144  of housing  142  and first end  136  of filter medium  134 . It should be appreciated, that as used herein, terms of approximation, such as “substantially” and “approximately,” refer to being within a ten percent margin of error. 
         [0051]    Although the one-way valves  180 ,  184  described above are ball check valves, one skilled in the art will appreciated that many other types and configurations of one-way valves are possible and within the scope of the present subject matter. For example, in alternative embodiments, one or more of one-way valve  184  in housing cap  160  and one-way valve  180  in first filter cap  158  may be configured as an umbrella type one-way valve, a duckbill type one-way valve, or any other suitable one-way valve. 
         [0052]    Referring now generally to  FIGS. 4 through 9 , aspects of the present invention will be described. More specifically,  FIG. 4  provides a cross-sectional view of an exemplary water filter assembly and  FIG. 5  provides a close up, perspective view of a housing cap.  FIGS. 6 and 7  provide close up cross-sectional views of first end of housing and housing cap with filter medium and first filter cap removed for clarity in describing particular aspects of the water filter assembly  120  and housing cap.  FIGS. 8 and 9  illustrate exemplary embodiments of valve screen assemblies described in detail below. 
         [0053]    As shown in  FIGS. 4 through 6 , housing  142  may further include a valve screen assembly  200 . Valve screen assembly  200  may further comprise a valve screen  202  positioned between one-way valve  184  and unfiltered water chamber  150  which is configured to filter unfiltered water passing from unfiltered water chamber  150  through one-way valve  184  to the reservoir  108 . Valve screen assembly  200  may be disposed in a channel  204  defined by housing cap  160 . More specifically, channel  204  may be a substantially cylindrical channel extending between an upstream end positioned in unfiltered water chamber  150  to a downstream end positioned proximate a top surface  206  of housing cap  160 . Housing cap  160  may further define one or more vent apertures  208  in top surface  206 , and downstream end of channel  204  may be in fluid communication with vent apertures  208 , thereby fluidly connecting unfiltered water chamber  150  to reservoir  108 . 
         [0054]    Valve screen assembly  200  may be disposed upstream of one-way valve  184  such that valve screen  202  filters any fluid flowing through one-way valve  184 . More particularly, valve screen  202  may remove any debris, sediment, or contaminants in the water or air flowing from unfiltered water chamber  150  through one-way valve  184  to reservoir  108  before the water reaches one-way valve  184 . Removing sediment and contaminants upstream of one-way valve  184  is particularly advantageous because foreign materials carried in water or air through one-way valve  184  can prevent it from operating effectively by interfering with the sealing surface. For example, when one-way check valve  184  is a simple check valve with a flap that forms a seal with a sealing surface when reverse flow occurs, contaminants that have built-up or become attached to the sealing surface may prevent the flap from forming a proper seal. When this occurs, fluid may flow around the flap in both directions, thus defeating the purpose of one-way check valve  184 . 
         [0055]    According to the illustrated embodiment described above, one-way valve  184  may be positioned within channel  204 , such that it is configured to prevent fluid flow from reservoir  108  to unfiltered water chamber  150 . To prevent air or water from flowing from reservoir  108  around the sides of one-way valve  184 , an outer surface  210  of one-way valve  184  may define an annular indentation  212  ( FIG. 9B ) that may receive a seal  214 , e.g., an O-ring. However, according to alternative embodiments, channel  204  may not be needed for operation. Instead, one-way valve  184  may be installed and sealed directly over vent apertures  208  of housing cap  160 . Other configurations are also possible. Indeed, any manner of positioning a one-way valve between unfiltered water chamber  150  and reservoir  108  to prevent reverse flow from reservoir  108  may be within the scope of the present subject matter. 
         [0056]    According to the exemplary embodiment illustrated in  FIGS. 6 through 8 , valve screen assembly  200  includes valve screen  202  which may be attached to a hollow cylinder  216 . Hollow cylinder  216  may have an outer surface  218  defining an annular indentation  220  configured to receive a seal  222  that extends circumferentially around outer surface  218 . Seal  222  may provide a seal between hollow cylinder  216  and channel  204  when hollow cylinder  216  is inserted into channel  204  as described below. In this manner, seal  222  prevents unfiltered water from flowing around the sides of valve screen assembly  200 , instead forcing all air and water through a hollow center  224  of hollow cylinder  216 , and thus through valve screen  202 , which covers hollow center  224 . 
         [0057]    Hollow cylinder  216  may be made from any suitably rigid material that may be configured to receive seal  222  and valve screen  202  as described above. For example, hollow cylinder  216  may be made of plastic, and may be injection molded to the desired size and shape. Valve screen  202  may be attached after hollow cylinder  216  is constructed using a suitable adhesive, mechanical fasteners, or another method of attaching valve screen  202 . Alternatively, according to the illustrated embodiment, valve screen  202  may be integrally molded into hollow cylinder  216 . This may be achieved, for example, by pressing valve screen  202  onto hollow cylinder  216  while it is not fully hardened and is still malleable. In this manner, plastic from hollow cylinder  216  may flow into the mesh of valve screen  202  and create a mechanical bond upon hardening. According to some exemplary embodiments, valve screen  202  may be constructed of a material similar to hollow cylinder  216 , or may have a similar coating, which when heated along with hollow cylinder  216  forms a chemical bond between valve screen  202  and hollow cylinder  216 . Alternatively, valve screen  202  may simply be placed in the mold prior to injection molding hollow cylinder  216  to achieve suitable mechanical and/or chemical bonding. According to another alternative embodiment, hollow cylinder  216  may be made from a resilient material that may be pressed into channel  204  such that hollow cylinder  216  forms a seal with channel  204  even without the need of seal  222 . 
         [0058]    According to an alternative exemplary embodiment, valve screen  202  may be attached directly to one-way valve  184 . More specifically, valve screen  202  may be attached to one-way valve  184  such that an inlet  226  of one-way valve  184  is covered by valve screen  202 , such that water may only flow into one-way valve  184  through valve screen  202 . Valve screen  202  may be attached to one-way valve  184  in the same manner described above for valve screen assembly  200 . For example, valve screen  202  may be attached using an adhesive, a mechanical faster, or it may be integrally molded into one-way valve  184 . 
         [0059]    As described above and shown in  FIGS. 9A and 9B , when valve screen  202  is attached directly to one-way valve  184 , seal  214 , which is similar to seal  222  of valve screen assembly  200 , prevents fluid from escaping to reservoir  108  between the sides of one-way valve  184  and channel  204 . One-way valve  184  may be installed in the same manner described above with respect to valve screen assembly  200 . More specifically, one-way valve  184  may be pressed into channel  204  and may rely on the compression of seal  214  to secure it in place. 
         [0060]    According to an exemplary embodiment, channel  204  may define a necked portion  232  having a smaller diameter than a nominal diameter of channel  204 . In this manner, one-way valve  182  may be pushed into channel  204  past necked portion  232  to secure one-way valve  184  within channel  204 . More specifically, as one-way valve  184  is pressed into channel  204 , seal  214  is highly compressed. As one-way valve  184  is pushed upward and passes necked portion  232  of channel  204 , the diameter of channel  204  increases, but seal  214  is still sufficiently compressed to form a seal between one-way valve  184  and channel  204 . In this manner, any force commonly experienced during operation of beverage dispenser  100  that tends to push one-way valve  184  back through channel  204  will be insufficient to push one-way valve  184  past necked portion  232 . Similarly, when valve screen  202  is part of a standalone valve screen assembly  200  having its own seal  222 , valve screen assembly  200  may be pressed into channel  204  and secured in the same manner, thus locking both valve screen assembly  200  and one-way valve  184  in channel  204 . 
         [0061]    Valve screen  202  may be made from any material suitable for filtering fluids flowing from unfiltered water chamber  150  to reservoir  108 . Valve screen  202  is typically a mesh screen having a plurality of openings  234  sized to prevent the passing of a particular size or type of sediment or contaminants. The material used for valve screen  202  is preferably rigid enough to maintain mesh geometry and capable of withstanding prolonged operation without degradation. According to an exemplary embodiment, valve screen  202  is made from a hydrophobic material. Hydrophobic materials are useful because they tend to repel water and decrease surface tension between openings  234  of the mesh when wetted, thus decreasing flow resistance. The size of openings  234  may vary depending on the application, but opening  234  sizes are typically less than 1/16 inch. 
         [0062]    Notably, opening  234  sizes may depend on the material used. For example, according to one exemplary embodiment, valve screen  202  may be made of polypropylene and may preferably define mesh openings  234  that are approximately 0.0041 inches wide. According to another exemplary embodiment, valve screen  202  may be made of Teflon-coated stainless steel and may define mesh openings  234  that are approximately 0.0014 inches wide. Other valve screen  202  materials may be used and different mesh size openings  234  are possible. In addition, mesh size openings  234  may be non-uniform over valve screen  202  and may be square, circular, oblong, or any other size suitable for filtering particulates. 
         [0063]    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 language of the claims.