Abstract:
Fouling of traps from grease and similar effluents from restaurants and like facilities is reduced by using a concrete grease trap having an internal baffle plate, with an impervious liner fitted within the grease trap to restrict the outflow of grease and to prevent intrusion of grease into the walls of the concrete trap.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/616,469, filed Oct. 6, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety, and which is commonly owned with this application. 
     
    
     FIELD OF INVENTION  
       [0002]     The present invention generally relates to systems and methods for treating grease and similar effluents in wastewater outputs from restaurants and like facilities.  
       BACKGROUND  
       [0003]     It is well known to place a liner with a concrete tank such as a septic tank or waste disposal tank. See, for example, the following United States patents and published applications: U.S. Pat. No. 4,613,922 to Bachmann; U.S. Pat. No. 3,662,918 to Crawford et al.; U.S. Pat. No. 3,898,162 to Carlson et al.; U.S. Pat. No. 3,957,416 to Kaempen; U.S. Pat. No. 4,162,976 to Monson; U.S. Pat. No. 4,465,594 to Laak; U.S. Patent No. RE31,753 to LaVergne Jr.; U.S. Pat. No. 5,044,778 to Hines; U.S. Pat. No. 5,101,849 to Richard; U.S. Pat. No. 5,454,544 to Del Zotto; U.S. Pat. No. 5,582,310 to Del Zotto; U.S. Pat. No. 5,601,204 to Hall; U.S. Pat. No. 5,772,361 to Gavin; U.S. Pat. No. 5,799,817 to Sharp; U.S. Pat. No. 6,202,370 to Miller et al.; U.S. Pat. No. 6,206,226 to Coates; U.S. Publication No. 2001/0025853 to Piehler; U.S. Pat. No. 6,387,524 to Finefrock; U.S. Pat. No. 6,606,836 to Miller; U.S. Publication No. 2004/0245255 to Copley et al.; U.S. Publication No. 2005/0184000 to Jowett.  
       SUMMARY  
       [0004]     The present invention is directed to a system and method for reducing runoff of grease and similar effluents from restaurants and like facilities where the grease and effluents are injected into either a conventional local drainage facility or into a municipal waste water system.  
         [0005]     In a preferred embodiment, a hollow concrete grease trap shell is provided with a liner impervious to grease and effluents with an internal baffle to separate the grease from any liquid effluent, to thereby significantly reduce the amount of grease injected into a drain field associated with the grease trap shell. The plastic (i.e., polyethylene) liner prevents invasion of the grease and other effluents through the concrete wall of the outer shell. Other features, such as a sealing cap are utilized to further reduce grease and effluent intrusion into the shell.  
         [0006]     The plastic liner may be inserted into the concrete shell at the manufacturing facility, or alternatively installed into an existing grease trap. In either event, the plastic liner is welded at the corners to form a watertight seal. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]     For a fuller understanding of the invention, reference is made to the following detailed description, taken in connection with the accompanying drawings and photographs illustrating various embodiments of the present invention, in which:  
         [0008]      FIG. 1  is a schematic illustration of a restaurant facility having a grease trap and drain field of the type which may utilize the system and method of the present invention.  
         [0009]      FIG. 2  is a schematic illustration of a restaurant facility having a grease trap coupled to a municipal treatment system.  
         [0010]      FIG. 3  is an exploded perspective view of a prefabricated tank liner inserted into a concrete tank.  
         [0011]      FIG. 4  is a partial perspective view of a concrete tank prior to having a liner inserted therein.  
         [0012]      FIG. 5  is a partial perspective view of a concrete tank having a partition wall therein in accordance with an alternate embodiment.  
         [0013]      FIG. 6  is a side perspective view illustrating a first embodiment of a prefabricated tank liner.  
         [0014]      FIG. 7  is an end elevation view of the prefabricated liner of  FIG. 6 .  
         [0015]      FIG. 8  is a perspective view of an inside portion of the prefabricated liner of  FIGS. 6 and 7 .  
         [0016]      FIG. 9  is a partial cross sectional view of a portion of the concrete shell-plastic liner construction, illustrating the upper sealing cap feature.  
         [0017]      FIG. 10  is a cross sectional illustration of a grease trap in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     The present invention will now be described more fully with reference to the accompanying drawings in which alternate embodiments of the invention are shown and described. It is to be understood that the invention should not be construed as limited to the illustrated embodiments set forth herein. Rather, these embodiments are provided so that this disclosure may be thorough and complete, and will convey the scope of the invention to those skilled in the art.  
         [0019]     First noting  FIG. 1 , the system and method of the present invention is useful in an installation, referred to generally by  10 , where a restaurant  12  has an outflow  14  to a grease trap  16 . Typically, when the grease trap is not connected to a municipal waste water system, the grease trap  16  is provide with an outflow  18  to a conventional drainage field, including lateral mainlines  20  and individual feeder lines  22 , through which the effluent from the grease trap is extended through the soil for anaerobic treatment and percolation. When the restaurant  12  is generating a significant amount of excess grease into the trap  16 , frequently the grease will flow into the drain field lines  20 ,  22 . This can cause not only blockage of the percolating openings of the lines  20 ,  22 , but can also create environmental hazards. Many local and state ordinances contain specific restrictions on the amount of grease effluent that can be emitted into a drain field. More importantly, however, is the effect that grease and similar effluents can cause within the grease trap  16 . It is well known that concrete is somewhat porous, and that grease will migrate into and through a concrete barrier. Therefore, in accordance with the present invention, an impervious liner and barrier system has been developed which resolves many of the above-noted problems with conventional concrete grease traps.  
         [0020]     The system and method of this invention is also useful with a restaurant or like facility that is coupled to a municipal wastewater treatment facility, as shown in  FIG. 2 . In this arrangement, the installation  11  with restaurant  13  having an outflow  15  coupled to a grease trap  17 . Outflow  19  is coupled in a conventional manner to a municipal wastewater facility MF.  
         [0021]     As will be understood by those skilled in the art from a review of the cross-section of  FIG. 10  and the description set out below, a grease trap in accordance with this invention has an impervious sidewall and end wall construction that protects the walls of a concrete shell while providing an efficient trap for grease entrained with liquid effluent.  
         [0022]     Now noting  FIG. 3 , one embodiment of a grease trap in accordance with the present invention includes a concrete outer shell  110  having a bottom  112 , end walls  114 ,  116  and opposing sidewalls  118 ,  120 . A cover  122  encloses the entire construction. The concrete shell has an outlet opening  124  in the end wall  114  and an inlet opening  126  in the opposing end wall  116 . A plastic liner  130  is provided, and may be installed either at the manufacturing facility directly into the concrete shell  110  or alternatively may be installed on site at a grease trap location. In the embodiment of  FIG. 3 , the plastic liner, which may comprise sheet polypropylene, for example, has a bottom  132  opposing end walls  134 ,  136  and opposing sidewalls  138  and  140 . The liner end wall  134  has an outlet  144  and the opposing end wall  136  has an inlet  146 .  
         [0023]     Further in accordance with the present invention, the embodiment of the liner  130  shown in  FIG. 3  includes a vertical baffle plate  148  extending between the opposing end walls  134 ,  136  between the opposing sidewalls  138 ,  140 . As shown in  FIG. 2 , the baffle  148  is positioned further from the end wall  136  having the opening  146 , as described below, so as to form a grease retention volume between the baffle  148  and the end wall  136  (see  FIG. 10 ).  
         [0024]     In accordance with another aspect of the present invention, the concrete shell  110  may be provided with opposing slots  128 ,  129  in the opposing sidewalls  118 ,  120  so as to permit the insertion of a concrete baffle  115 , as shown in  FIG. 5 . In that instance, the plastic liner is formed of two parts, a first part to surround the volume adjacent the opening  114 , and a second plastic liner fitted in the volume defined by the end wall  116  and the remaining portions of the opposing side walls  118 ,  120 .  
         [0025]     Another aspect of the preferred embodiment is shown in  FIG. 9 , which depicts a ceiling cap  152  comprising an L-shaped member of plastic liner material (e.g. polypropylene) having a vertically extending arm  154  and a horizontally extending arm  156 . The cap  152  is preferably caulked to the top of the concrete wall, for example end wall  114 , with a bead of silicon caulking material  158 . A tap-end fastener  160  may also be utilized to ensure that the cap member  152  remains in place.  
         [0026]     A cross section of the embodiment of  FIG. 2  is illustrated in  FIG. 10 . As shown there, the volume between the end wall  136  and the baffle  148  forms a reservoir for grease G across the top of the reservoir, since the grease G is lighter than the liquid effluent LE. The liquid effluent LE flows through the opening  149  in the baffle  148  and into the volume defined between the baffle  148  and the opposing end wall  134 . As the level of the liquid effluent LE reaches the opening  124 , the liquid effluent LE flows through the outflow  18  into a connected drain field lines  20 ,  22  ( FIG. 1 ) or into a municipal wastewater treatment facility MF ( FIG. 2 ).  
         [0027]     Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore it is to be understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and alternate embodiments are intended to be included within the scope of the claims supported by this specification.