Patent Abstract:
An in-line filter and method for reducing the solids content of a liquid passing through a storm sewer line. The frame of the filter is provided with a screen and optionally, filter media, and is decreased in size until the frame is small enough to fit into the storm sewer line into which liquids carrying solids and pollutants pass. The frame is then expanded into frictional engagement against the inside surface of the line.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an apparatus and method for reducing the pollutants in storm water runoff passing through a storm sewer line. More specifically, the present invention relates to an apparatus for easily mounting a reusable filter inside a line for removing pollutants from a liquid passing through a storm sewer line.  
           [0002]    The present invention has particular application to disturbed construction sites, where rain on bare ground has the result of washing large quantities of solids from the site and into the storm drainage system. In addition to the undesirable removal of soil from the site, the solids washed from the site can settle in the storm sewers and/or receiving streams or channels, and can have the result of interfering with the function of the receiving streams or channels and/or contaminating the receiving streams or channels. Of course the solids that wash off of the construction site are often not just dirt and particulate solids—it is not uncommon for the run-off to include trash, building materials, and other solids that can do more than just interfere with the function of the drain and/or sewer.  
           [0003]    For these, and other reasons, it is desirable to prevent entry of the solids in the run-off from disturbed construction sites. The importance of preventing the entry of solids from such sites into the storm sewer lines has even prompted regulatory action, and the present invention therefore provides a method to aide in compliance with Environmental Protection Agency regulations as set out in Title 40 of the Code of Federal Regulations, and specifically, the requirements of the National Pollution Discharge Elimination System regulations.  
           [0004]    One method that has been used to address this problem is to build a wood frame, staple fabric over the frame, position the frame over the opening of the storm sewer in the inlet box, and brace the frame against the inlet box walls. Although this construction can function to reduce the solids entering the drain, its relatively bulky construction makes it difficult to remove collected pollutants from the inlet box and to replace and/or maintain the fabric, which can compromise its effectiveness. Further, it must be purpose-built on-site and cannot be easily re-used.  
           [0005]    There is, therefore, a need for improvements in reducing the volume of pollutants contained in the water washing off a disturbed construction site, and it is an object of the present invention to provide such an improvement, specifically in the form of a filter that is adapted to fit inside the storm sewer line connected to the inlet box.  
           [0006]    However, those skilled in the art will understand from the following description that the present invention, while being originally intended for application in the above-described environment, has broader application in that it is useful in any environment in which it is desired to reduce the solids content of a liquid that is passing through a line. It is, therefore, an object of the present invention to provide an improved in-line filter for use in wide variety of applications in reducing the solids content of a liquid passing through a line.  
           [0007]    Another object of the present invention is to provide an apparatus and method for reducing the solids content of a liquid passing through a line that is easily and quickly installed before or as soon as the line is put into service.  
           [0008]    Another object of the present invention is to provide an apparatus and method for reducing the solids content of a liquid passing through a line that is durable and reusable.  
           [0009]    Another object of the present invention is to provide an apparatus and method for reducing the solids content of a liquid passing through a line that is easily cleaned and maintained.  
           [0010]    Another object of the present invention is to provide an apparatus and method for in-line filtering of solids from a liquid passing through the line that functions to allow the liquid to pass on through the line even when the filter of the present invention has trapped sufficient solids as to occlude a portion of the filter area.  
           [0011]    Another object of the present invention is to provide an apparatus and method that is adapted for easily switching the filter material mesh size and/or effective opening so as to remove the desired amount of solids from the liquid passing through the line and/or to remove solids of certain sizes from the liquid passing through the line.  
           [0012]    Yet another object of the present invention is to provide an apparatus and method that is adapted to provide for a variable by-pass area easily and economically so as to allow for adjustable by-pass flow to coincide with varying stages of development and pollutant levels in the storm water runoff.  
           [0013]    Other objects, and the advantages, of the present invention will be made clear to those skilled in the art by the following description of the presently preferred embodiments thereof  
         SUMMARY OF THE INVENTION  
         [0014]    These objects are achieved by providing an in-line filter for reducing the pollutant content of a liquid passing through a storm line comprising a first frame adapted for frictionally engaging the inside surface of a line and a second frame having a size and shape that allows the second frame to fit into the first frame after the size of the first frame is increased by expanding the first frame outwardly to receive the second frame therein. The filter media is retained between said first and second frames and an adjustment nut and bolt are mounted on the first frame for decreasing the size of the first frame after the second frame is received therein until the outside diameter of the first frame, having the second frame and the filter media assembled thereto, is small enough to fit into and frictionally engage the inside surface of the line.  
           [0015]    The present invention also provides a method for reducing the solids content of a liquid passing through a line comprising the steps of increasing the size of a first frame to accept a second frame therein, said second frame supporting the filter media, decreasing the size of the first frame to a size small enough to fit within the line in which it is desired to reduce the solid content of a liquid passing there through, and increasing the size of the first frame until the first frame frictionally engages the inside diameter of the line.  
           [0016]    These objects are also achieved by providing an in-line filter for reducing the pollutant content of a liquid passing through a line comprising a single frame adapted for frictionally engaging the inside surface of a line. The size of the first frame is increased by expanding the frame outwardly to frictionally engage the inside surface of a line. The filter media is retained between said frame and the inside surface of the line and an adjustment nut and bolt are mounted on the frame for decreasing and increasing the size of the frame until the outside diameter of the frame, is small enough to fit into the line and large enough to frictionally engage the inside surface of the line and retain the screen and/or filter media.  
           [0017]    The present invention also provides a method for reducing the solids content of a liquid passing through a line comprising the steps of increasing the size of the frame to the size of the line, said frame is covered with filter fabric and then covered with a stiff screen that is wrapped around said frame to hold the filter fabric in place, decreasing the size of the frame to a size small enough to fit within the line in which it is desired to reduce the solid content of a liquid passing there through, and increasing the size of the frame until the frame and filter media frictionally engage the inside diameter of the line. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is an elevation view of a preferred embodiment of an apparatus for reducing the solid content of a liquid passing through a line that is constructed in accordance with the teachings of the present invention and that is frictionally engaging the inside surface of a storm drain pipe.  
         [0019]    [0019]FIG. 2 is a sectional view of the apparatus of FIG. 1 taken along the lines A-A in FIG. 1.  
         [0020]    [0020]FIG. 3 is a detail view of the adjustment nuts and bolt of a presently preferred embodiment of the embodiment shown in FIG. 1.  
         [0021]    [0021]FIG. 4 is a sectional view of a second embodiment of the apparatus of the present invention.  
         [0022]    [0022]FIG. 5 is a detail view of the adjustment nuts and bolt of a second embodiment of the apparatus of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    Referring to the figures, a preferred embodiment constructed in accordance with the teachings of the present invention is indicated generally at reference numeral  10 . The apparatus  10  comprises a first frame  12  adapted for fitting into and engaging the inside surface of a storm sewer pipe  14  of conventional construction. By referring to FIG. 2, it can be seen that the first frame  12  is concentric with a second frame  16  and that a layer of wire mesh  18  is sandwiched between the two frames  12 ,  16 . In the particular embodiment  10  shown in FIGS. 1-3, the wire mesh  18  serves as a backing for a section of filter media  20  that is also sandwiched between the two concentric frames  12 ,  16  and that acts as a filter to reduce the solids content of liquid passing through the drain pipe  14 .  
         [0024]    It will be noted that, in the preferred embodiment shown, the filter media  20  does not necessarily cover the entire layer of wire mesh  18  or the second frame  16 . When the apparatus  10  of the present invention is placed into the drain pipe  14  with the first frame engaging the inside surface of pipe  14 , the filter media  20  functions to filter the solids from the water passing there through, with the resulting accumulation of solids at the upstream side of the apparatus  10 . Although not immediately apparent from the drawings, the size of second frame  16  is fixed, i.e., not adjustable. In the case of the round drain pipe  14  shown in the figures, because the drain pipe  14  is round, it is the diameter of the second frame  16  that is not adjustable, but those skilled in the art who have the benefit of this disclosure will recognize that the line in which the apparatus  10  is utilized need not be round such that the apparatus  10  may be shaped in any shape as required by the shape of the particular line in which the apparatus  10  is to be positioned. It is for this reason that the present specification refers to the “size” of the frames  12 ,  16  rather than using words such as “~diameter,” which carry connotations of shape, to describe the frames  12  and  16 . By contrast, the size of first frame  12  can be changed, and in particular, as best shown in FIG. 3, first frame  12  is provided with integral collars  22 A and  22 B, one on each free end of frame  12 , having an adjustment bolt  24  and nut  26  positioned thereon. In the particular embodiment shown in FIG. 3, the adjustment bolt  24  is threaded and extends through collar  22 B, adjustment nut  26  and collar  22 A and into a fixed threaded nut  28  that is fixedly attached to collar  22 A. Collar  22 A and threaded fixed nut  28  is arranged such that the rotation of bolt  24  causes collar  22 B to travel along the length of bolt  24 , thereby decreasing the size of the first frame  12  to which collars  22 A and  22 B are mounted. Similarly, the size of first frame  12  is increased by rotating bolt  24  until the head of the bolt  24  disengages the collar  22 B and creates a space between the head of bolt  24  and collar  22 B. Then, by rotation of the adjustment nut  26  while holding the bolt  24  fixed, collar  22 B travels along the length of bolt  24 , thereby increasing the size of the first frame  12  to which collars  22 A and  22 B are mounted.  
         [0025]    Those skilled in the art will, however, recognize that the size of first frame  12  can be changed in a number of ways that do not involve the adjustment bolt  24  and nut  26  such that the present invention should not be considered restricted in its scope to the particular size adjusting means shown in FIG. 3. It does happen, however, that a threaded adjustment bolt such as the bolt  24  is particularly useful for this purpose because it easily allows for varying degrees of change in size, thereby insuring secure engagement of the first frame  12  and the inside surface of the drain pipe  14 . Further, in the particular embodiment shown, the threaded adjustment bolt  24  is provided with an adjustment nut,  26  that rides on the threads of bolt  24 . When the apparatus  10  of the present invention is inserted into the storm drain pipe  14 , rotation of adjustment nut  26  toward the collar  22 B causes movement of collar  22 B relative to bolt  24 , and because collar  22 B is integral with first frame  12 , the movement of collar  22 B relative to bolt  24  causes the size of first frame  12  to increase so as to securely engage the inside surface of the drain pipe  14 .  
         [0026]    In the preferred embodiment shown in the figures, and specifically by reference to FIG. 2, it can be seen that the first and second frames  12 ,  16  are both “C”-shaped when viewed in section. This “C”-shape of first and second frames  12 ,  16  functions to resist movement of second frame  16  relative to first frame  12 , thereby affirmatively retaining the wire mesh  18  and filter fabric  20  therebetween. It will be recognized, however, by those skilled in the relevant art that the same goal is accomplished by rolling the edge of one or the other (or both) of first and second frames,  12 ,  16  to create a lip along the edge of the frames  12 ,  16  and/or by a detent or nipple formed in one or the other of frames  12 ,  16  to provide a snap or friction fit between frames  12 ,  16 .  
         [0027]    Referring now to FIGS. 4-5, there is shown an alternate embodiment of the apparatus  10  of the present invention in which like numerals are used to identify parts corresponding to the component parts of the embodiment shown in FIGS. 1-3. In this alternate embodiment, instead of two “C”-shaped frames, one frame  12  is covered with filter media  20  and the wire mesh  18  wrapped around the exterior surface and into the interior surface of frame  12 . Just as in the embodiment shown in FIGS. 1-3, the size of the frame  12  of the embodiment shown in FIGS. 4-5 can be changed. In particular, and as best shown in FIG. 5, frame  12  is provided with integral guides or collars  23 A and  23 B, one on each free end of frame  12 , having an adjustment bolt  24  and nut  26  positioned thereon. In the alternate embodiment shown in FIG. 5, the adjustment bolt  24  is threaded and extends through the guide or collar  23 B, adjustment nut  26  and guide or collar  23 A, and into a threaded nut  28  that is fixedly attached to guide or collar  23 A. Guide, or collar,  23 A and threaded fixed nut  28  are arranged such that the rotation of bolt  24  causes guide or collar  23 B to travel along the length of bolt  24 , thereby decreasing the size of the frame  12  to which guides or collars  23 A and  23 B are mounted. Similarly, to increase the size of the frame  12 , bolt  24  is rotated until the head of bolt  24  disengages the guide or collar  23 B and creates a space between the adjustment bolt  24  and collar  23 B. Then, by rotation of adjustment nut  26  while holding the bolt  24  fixed, guide or collar  23 B is caused to travel along the length of bolt  24 , thereby increasing the size of the frame  12  to which guides or collars  23 A and  23 B are mounted.  
         [0028]    Those skilled in the art who have the benefit of this disclosure will recognize that certain changes can be made to the component parts of the apparatus of the present invention without changing the manner in which those parts function to achieve their intended result. All such changes, and others which will be clear to those skilled in the art from this description of the preferred embodiments of the invention, are intended to fall within the scope of the following, non-limiting claims.

Technology Classification (CPC): 4