An apparatus for removing debris from water passing through a storm drain comprises a frame adapted to be positioned underneath a storm grate for receiving the water, the frame having a bottom side and major and minor sidewalls, the major sidewalls having openings therein for allowing water to pass; and a filter removably insertable along at least a portion of the major sidewalls for filtering debris from the water.

BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to a storm drain filter system for filtering water flowing into a storm drain. 
         [0003]    2. Description of the Prior Art 
         [0004]    Filtering systems useful for storm drains generally prevent silt and other debris (e.g., dirt, gravel, tree leaves, street trash, etc.) from entering the storm drain and sewer system. Silt and other debris entering the storm drains along with rainwater and other surface water run-offs may clog the storm sewers and cause street flooding and/or damage to water treatment facilities that treat the water from storm sewers. Such problems may be exaggerated and commonly found in many construction sites or similar locations. 
         [0005]    To prevent such problems, the inventor has invented a novel silt and debris filtering system for storm drains that is simple to install and easy to maintain. The filter system of the present invention is provided with filter units that are easily removed from the storm drains for cleaning or replacement. 
         [0006]    The closest prior art of which Applicant is aware, is U.S. Pat. No. 5,284,580, to Shyh, U.S. Pat. No. 5,480,254 to Autry, U.S. Pat. No. 5,855,774 to Boelter, and Publication US2004/0226869 to McClure. The Shyh reference teaches a refuse collecting frame wherein each lateral side and the bottom of the frame body are formed with the filtering net, and further teaches that an aperture is formed in the bottom wall. 
         [0007]    The Boelter and the McClure references teach the use of removable filter media, but do not teach the manner in which the Applicant provides for the positioning of different or multiple filter media, and the ease with which the Applicant's system allows for the removal, cleaning or replacement of the filter media. Still further, the apparatus of Boelter and McClure require basket type or tray type filters which are not required by Applicant. The Autry reference teaches the use of welded porous exterior and interior walls, with a filter media of crushed stone positioned there between clearly making it more difficult for the removal, cleaning, and/or replacement of filter media in a rapid and facile manner. 
         [0008]    Applicant respectfully submits that the design of Applicant's filtering system overcomes the shortcomings of the prior art. 
       OBJECTS OF THE INVENTION 
       [0009]    An object of the present invention is to provide for a novel storm drain filtering system which is easily installed. 
         [0010]    A still further object of the present invention is to provide for a novel storm drain filter which collects debris and thereby maintains the storm drain in a free flowing condition. 
         [0011]    A still further object of the present invention is to provide for a novel storm drain filter in which the filter elements are easily replaced. 
         [0012]    A still further object of the present invention is to provide for a novel storm drain element in which the filter elements can be effective against particulate matter and debris, as well as liquid contamination, such as petroleum products. 
       SUMMARY OF THE INVENTION 
       [0013]    An apparatus for removing debris from water passing through a storm drain comprises a frame adapted to be positioned underneath a storm grate for receiving the water, the frame having a bottom side and major and minor sidewalls, the major sidewalls having openings therein for allowing water to pass; and a filter removably insertable along at least a portion of the major sidewalls for filtering debris from the water. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    These and other objects of the present invention will become apparent, particularly when taken in light of the following illustrations wherein: 
           [0015]      FIG. 1  is a side cross-sectional view of a storm drain illustrating the positioning of Applicant's filtering system; 
           [0016]      FIG. 2  is a top view of Applicant's filtering system; 
           [0017]      FIG. 3  is an end view of Applicant's filtering system; 
           [0018]      FIG. 4  is an exploded view of Applicant's filtering system illustrating the types of filters slidably removable therein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    In accordance with an aspect of the present invention, and referring generally to  FIGS. 1 and 2 , the storm drain filtering system generally comprises a frame  10  configured and dimensioned to be positioned underneath a storm drain grate  12  and one or more modular filter screen units that re removable from the frame for cleaning and/or replacement. 
         [0020]    In an exemplary configuration, the frame  10  is a rectangular box-like structure having a solid bottom side  14  and four side walls comprising two shorter minor sides  16  and  18  and two longer major sides  20  and  22 . The two minor sides oppose each other and the two major sides oppose each other. In a preferred embodiment of the present invention, the minor sidewalls  16  and  18  are solid and the two major side walls are grated. The grating structure of the sidewalls may be varied in size and shape to accommodate the particular filtering needs of a given application or an installation site for the storm drain filtering system. In  FIG. 1  the grate openings  24  on the major side walls are shown as rectangular, there being a single vertical divider  26 . 
         [0021]    The tope side of the frame is open to let the water flow into the frame. The top edge (or lip)  28  of the frame may be configured and adapted to be supported by or hang from supporting structures  30  that may be mounted into the wall  32  of the catch basin of the storm drain  34  below the storm grate  12 . The support structures may be ledges or hooks. In an embodiment of the present invention illustrated in  FIG. 1 , the supporting structures are ledges formed by stainless steel angle irons that are drilled and mounted into the wall of the catch basin by bolts or other suitable hardware. In another embodiment of the present invention, the supporting structures may be hooks. 
         [0022]    The top edge (or lip)  28  of the frame may be provided with a flange portion that may hang from the supporting structures, whether the supporting structures may be ledges or hooks. One or more handle(s)  36  having an appropriate shape may be provided along the top edge (or lip)  28  of the frame for ease of handling the frame during installation of or removal of the storm drain filter system. 
         [0023]    As illustrated in  FIG. 1 , the minor side walls  16  and  18  of the frame may be tapered so that the frame is wider at the top than the bottom. As illustrated in  FIG. 2 , the solid bottom side  14  of the frame may have a central ridge  38  that is raised along the longitudinal axis of the frame so that the solid bottom side is pitched downwardly from the central ridge toward the two major side walls  20  and  22 . This configuration assists the water flowing into the frame to flow outwardly towards the major side walls to where the modular filter screens  100  are located and out of the frame, thereby preventing unwanted collection of water in the frame. 
         [0024]    As illustrated in  FIG. 3 , the solid minor side walls may be provided with one or more overflow holes  40  near the top to allow water to overflow, in the event that the filter system is filled with filtered debris and/or silt. 
         [0025]    The major side walls of the frame may be provided with one or more side drain holes  42  along the bottom edge as shown in  FIG. 1 . 
         [0026]    All or most of the components of the storm drain filtering system according to the present invention may be made of a variety of materials appropriate for such application. Preferably, the components, including the frame and the modular filter screen units may be made from appropriate'gauge and grade of stainless steel that provides appropriate structural strength, durability and corrosion resistance. An example of such material is 304 stainless steel. 
         [0027]    The filter system of the present invention also includes modular filter screens  100  for each of the grated major side walls  20  and  22 . The modular filter screens  100  are removably mounted parallel to each of the two major side walls from inside the frame in slotted pathways or channels  49  defined by major side walls  20  and  22  and vertical flange pairs  50  and  52  allowing for either 1 or 2 modular filter screens to be associated with each major side wall  20  and  22 . 
         [0028]    The modular filter screens  100  as illustrated in  FIG. 4  may be a mesh or perforated sheet of some appropriate material. Preferably, the modular filter screens are made from perforated stainless steel sheets of an appropriate gauge that can withstand the structural demand of retaining silts and other debris that are being collected inside the frame and the pressure of the flowing water through the filter screens. In one embodiment of the present invention, 16 gauge grade 304 stainless steel that is perforated with ⅛″ diameter holes on ⅜″ centers, staggered, may be used for the filter screens. Depending on the range of the particle size of the debris to be filtered and collected by the filtering system, the diameter and the spacing of the perforation and the gauge of the stainless steel spacing of the perforation and the gauge of the stainless steel spacing of the perforation and the gauge of the stainless steel sheet may be varied accordingly. 
         [0029]    The perforation also may be any appropriate shape other than circular holes. The density of the perforations on the filter screens may be uniform throughout a given screen or, if necessary, the density of the perforations may vary across the height and width of the filter screen. For example, the perforations near the bottom end of the filter screen may have smaller and denser holes to filter silts and other debris having finer article size. The perforations near the top end of the filter screen may have larger and less densely populated holes to filter and collect larger particle size debris. 
         [0030]    An example of a modular filter screen  100  is illustrated in  FIG. 4 . The outline shape of the modular filter screen unit preferably matches the shape of the major side walls  20  and  22  of the frame  10 . The modular filter screen  100  may be constructed to have a frame portion  110  supporting the perforated stainless steel sheets  112  or screens  113 . The frame portion  110  of the module filter screen unit may be configured like a picture frame with one central opening  114  or may be configured with one or more cross-members  116  that divide the central opening  114  into two or more screen sections  118 . Such cross members  116  may provide further structural support for the filter screen to prevent the filter screen from blowing out from the water pressure or the pressure exerted by the silts and debris collecting inside the frame. 
         [0031]    If the cross-members  116  of the modular filter screen units are sufficiently strong, the frame of the filter system may not need the grating structure  26  for the major side walls. In that embodiment of the present invention, the major side walls of the frame may be just a big opening. 
         [0032]    The modular filter screen units may be configured and dimensioned to slidably engage the frame. The frame is provided with channels  49  along the side edges of the two major side walls along their inside surface as defined by flange pairs  50  and  52 . The channels  49  preferably extend substantially the full height of the frame. Of course, the channels may also be embodied as clips or other fastening and/or guiding mechanisms. The side edges of the modular filter screen units are configured and dimensioned to engage the channels  49  of frame  10  by sliding into the channel from the top. 
         [0033]    To install the filtering system of the present invention, the storm drain grate is lifted up or tilted up from its normal resting position exposing the storm drain opening. If the storm drain opening does not have ledges or other suitable support structure for holding the frame of the filtering system, suitable supporting structure(s)  30  illustrated in  FIG. 1  are installed into the wall of the catch basis. Such supporting structures include an L or U-shaped support having a first end for mounting (e.g. via bolts) to the wall and a second end mountable to the frame. The frame of the filtering system is then dropped into the storm drain opening such that the flange portion along the top edge of the frame rests on the supporting structure(s). Appropriate modular filter screen units are then installed on each side of the major side walls of the frame by sliding the modular filter screen units into the channels of the frame. It should be noted that multiple filter members can be used with each major side wall as there are two channels associated with each. 
         [0034]    In an exemplary embodiment, a stainless steel wire mesh screen (e.g. a 200 mesh counter per inch or 0.0029 inch width opening) and a 1.5 inch thick replaceable filter for collecting debris including petroleum hydrocarbons is provided. The filter and screen may each be separately removable in a vertical fashion independent of one another. 
         [0035]    The members of the public works or road maintenance crew will periodically inspect the storm drains installed with the filtering system of the present invention. If the filtering system is filled with silt or other debris, the debris may be removed by, for example, using a jet-vacuum after the storm grate is removed. If appropriate, each of the modular filter screens also may be temporarily removed for cleaning. Because the components of the filter system, including the modular filter screen units are made of stainless steel, they are corrosion resistant and should be reused without being replaced for a long time. 
         [0036]    Therefore, while the present invention has been disclosed with respect to the preferred embodiments thereof, it will be recognized by those of ordinary skill in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore manifestly intended that the invention be limited only by the claims, and the equivalence thereof.