Abstract:
A strainer for a water pump includes a bottom panel and an upwardly extending side panel forming a cavity. The base of the water pump is received within the cavity and is removably secured to the filter.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
   None. 
   BACKGROUND OF THE INVENTION 
   The present invention relates generally to the field of water pump filters and more particularly, to a removable strainer for an evaporative cooler. 
   Evaporative coolers are well know and used in warm arid climates to cool the air. Conventional evaporative coolers work by drawing air from outside through a rigid media soaked with water. As the air flows through the media soaked with water, the water is evaporated by the outside air thereby lowering the temperature of the air. The cooled air is then directed into the area to be cooled. 
   Conventional evaporative coolers include a number of elements stored in a housing. These elements typically include an air blower, a media pad, a water distribution system, and an electric motor. The water distribution system includes a water pump that draws water from a collection pan in the bottom of the housing and pumps the water through tubing to the top of the media pad or pads. Some of the water in the media pads is evaporated as air is drawn through the media. The remaining water that is not absorbed in the media returns to the collection pan in the bottom of the housing. In this manner the water is recirculated. Fresh water is added only to replace the water that has been evaporated. 
   It is not desirable to circulate any debris, that may fall into the collection pan. The debris can both clog the pump and/or the media. Debris may fall into the housing during installation of the evaporative cooler or during replacement of the media. Additionally, since the water is being recirculated any minerals in the water tend to build up overtime in the collection pan. One method of removing the mineral buildup is to intentionally replace the water in the collection pan on a periodic basis. To minimize debris from entering the water pump a filter or strainer may be used. One such filter or strainer is disclosed in U.S. Pat. No. 3,046,900 issued on Jul. 31, 1962 to Pollak which illustrates a two piece filter element that fits on top of a portion of the pump. Since this filter only covers the top of a base portion of the of the water pump, debris that is on the bottom of the collection pan may still enter the pump. 
   Another attempt to introduce a filter is disclosed in U.S. Pat. No. 4,856,971 issued on Aug. 15, 1989 to Koble. The filter disclosed in Koble includes a number of thin slits that are formed directly through the lower portion of the base. Similarly, Koble does not filter any debris located on the base of the pan. 
   Since, the collection pan is typically not completely planar debris is able to enter below the lower edge of the housing. As soon as an opening exists between the lower edge of the water pump and the collection pan, debris can enter this opening and be circulated by the pump and/or clog the pump. Additionally, since the slits are part of the pump itself if the slits become clogged it is necessary to remove the entire pump in order to clean the filter portion. 
   Accordingly, there is a need for a filter for a water pump that filters out debris located on the bottom of the collection basin. There is also a need for a filter that can be easily removed from the water pump housing for cleaning and or replacement. 
   SUMMARY OF THE INVENTION 
   One embodiment of the invention relates to a strainer for a water pump. The strainer includes a bottom panel and an upwardly extending side panel forming a cavity. The base of the water pump is received within the cavity and is removably secured to the filter. 
   Another embodiment of the invention relates to a strainer for an evaporative cooler pump. The strainer includes a bottom panel including a plurality of slits extending therethrough and an upwardly extending side panel having a plurality of slits extending therethrough. The bottom panel and side panel define a cavity configured to receive a portion of the water pump within the cavity. 
   A further embodiment of the invention relates to a method of releasably securing a strainer to a pump filter. A strainer is provided having a bottom panel having an outer periphery. The strainer includes a side wall extending upwardly from the bottom panel about the periphery. The bottom panel and side wall defining a cavity. A water pump is provided having a base portion. The base portion of the water pump is placed within the cavity of the strainer. The base portion and strainer are operatively secured to one another. 
   In a further aspect of the invention, the strainer is operatively connected and removed form the water pump without the use of tools. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric view of a water pump and filter. 
       FIG. 2  is an exploded view of the filter and base of the water pump. 
       FIG. 3  is cross-sectional view of the water pump and filter taken generally along the lines  3 — 3  of  FIG. 1 . 
       FIG. 4  is a partial cross sectional and exploded view of the filter being directed upwardly toward the water pump housing taken generally along lines  6 — 6  of  FIG. 3 . 
       FIG. 5  is a partial cross sectional view of the filter being located within the water pump housing in the engaged position and taken generally along lines  6 — 6  of  FIG. 3 . 
       FIG. 6  is a partial cross sectional view of the filter in the fully engaged position and taken generally along lines  6 — 6  of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , a water pump  10  for an evaporative cooler includes a housing  12  in which a motor is located. A pair of supports  14  separate the motor housing  12  from a base  16 . A shaft  18  operatively driven by the motor located within motor housing  12  drives pump impeller  20 . Water is pumped upward through guide  22  to a distribution system (not shown). A filter or strainer  24  is releasably secured to base  16 . 
   Referring to  FIG. 2 , strainer  24  includes a bottom panel  26  and an upwardly extending side wall  28 . Bottom panel  26  may include feet  30  extending downwardly there from that rest upon the housing surface or a collection pan within the housing. Bottom panel  26  includes a plurality of arcuate slits  32  that are separated by a plurality of radial members  34 . Of course slits  32  may be other shapes as well. For example slits  32  may be straight or other fanciful shape. The slits may extend in parallel lines or may extend in a radial fashion from a center  36  of the bottom panel  26 . Bottom panel  26  further includes a solid perimeter region  36  extending about its periphery  38 . Feet  30  extend from perimeter region  36  proximate the periphery  38 . 
   Side wall  28  extends upwardly from bottom panel  26  proximate periphery  38 . Side wall  28  includes a plurality of slits  40  extending between periphery  38  of bottom panel  26  and an upper edge  42 . Side wall  28  includes an exterior surface  44  and an opposing inner surface  46 . Extending inwardly from inner surface  46  are four tabs  48 . In one embodiment, there is no slit through side wall  28  in the region between the base plane  26  and tab  48 . Referring to  FIGS. 2 and 3  base plane  26  includes an opening  50  located directly below each tab  48 . Opening  50  facilitates the manufacture of the strainer  24 , when the strainer  24  is formed in a mold from a material such as plastic. 
   Referring to  FIGS. 2 and 3  base  16  includes feet  52  extending downwardly from a separator member  54 . Shaft  18  extends through an opening  56  located in separator member  54  and is operatively connected to impeller  20 . An impeller housing  56  supports impeller  20  and is secured to separator member  54  by the insertion of beveled supports  57  that extend through openings  60  in separator member  54 . 
   Base  16  includes a lower radial support ring  58  having a bottom surface  64  and a top surface  66 . Four openings or grooves  68  extend through support ring  58  from bottom surface  64  to top surface  66 . Extending from the top surface  66  proximate one side of opening  68  is a stop  70 . Extending upwardly from top surface  66  on the other side of the openings  68  is a beveled raised guide member  72 . Guide member  72  extends upwardly 0.050 inches. Referring to  FIGS. 4–5  tab  48  includes a lower surface  74  having a downwardly extending bump or ridge  76  located on one side of the lower surface. Strainer  24  is secured to base  16  by aligning tabs  48  with grooves  68 , Strainer  24  is then moved toward base  16  until the bottom surface  64  of radial ring  58  contacts the inner surface  59  of bottom panel  26  or until tabs  48  clear the upper surface of support ring  58 . Strainer  24  is then rotated clockwise relative to base  16  such that tab  48  extends over beveled guide  72 . Strainer  24  is rotated until tab  48  contacts a stop  70  proximate an adjacent opening  68 . Tab  48  rests on the upper surface  66  of radial ring  58  thereby securing the strainer to the base  16 . Alternatively, in an operative position radial support ring  58  rests on the inner surface of the bottom plate of the strainer. If the pump filter is raised upwardly, tabs  48  will contact the upper surface of the radial support ring  58  thereby securing the strainer to the water pump. 
   Referring to  FIG. 3  water pump  10  rests on strainer  24  which in turn rests on the collection pan or housing  74 . Feet  30  raise the strainer off of the collection pan or housing to facility the free flow of water into the pump through opening slits  32  on the base plate  26  and through opening slits  40  on the side wall. 
   Strainer  24  may be removed from base  16  by simply rotating strainer  24  counterclockwise relative to base  16  until tab  48  is located over groove or opening  68  at which point the strainer is lowered until tab  48  is free of groove  68 . In this manner the strainer may cleaned and replaced or a new strainer may be attached. 
   In this embodiment, no tools are required to assemble or remove the strainer  24  from the base  16 . This reduces the time of assembly and further reduces the parts required for the water pump as a whole thereby reducing costs as well. In another embodiment strainer  24  may be secured to housing  16  with a separate fastener that is known in the art. Such fasteners may or may not require a tool. For example the use of screws would require a screw driver both to attach and remove the strainer from the housing. 
   It is important to note that the construction and arrangement of the elements of the strainer and water pump as shown in the preferred and other exemplary embodiments is illustrative only. Although only a few embodiments of the present invention have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g. variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, a tab could be located on the base instead of the strainer and similarly, the radial ring and grooves may be located on the strainer. Additionally, other types of mechanical fastening means may be used to releasably secure the strainer to the base. For example, the strainer may be snap fit to the water pump such that a portion of the strainer and water pump deform or bend as the strainer and water pump are being engaged and then the portion snap backs to its original shape to secure the strainer and water pump to one another. In this manner the strainer and water pump remain attached to one another until a sufficient force is applied to remove the two components from one another. Additionally, in a preferred embodiment filter or strainer  24  is a unitary component. However, multiple piece strainers may be used. Further, strainer  24  may be formed with an anti-microbial additive. The anti-microbial additive may formed with the plastic or other material, or the anti-microbial additive may be applied to the surface of the finished product. The use of an anti-microbial additive helps retard the growth around the strainer and therefore helps prevent plugging of the strainer itself. Accordingly, all such modifications are intended to be included within the scope of the present invention as defined in the appended claims. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the present invention as expressed in the appended claims.