Abstract:
An expansion ring has multiple adjustable expansion joints and plural bolts around the periphery of the ring that have pointed tips that bear into the sides of an existing manhole. The combination of the expansion joints and bolts allows the expansion ring to be securely affixed in the manhole. A filter basket assembly is suspended from the expansion ring into the manhole. Plural expansion rings with filter basket assemblies are strategically located along a clean-out route so that a full Vactor truck or sweeper may be emptied—decanted—into the filter basket assemblies on-route rather than at a traditional treatment plants.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to an apparatus that allows a filter to be suspended in an existing manhole so that fluids may be decanted and filtered as they are emptied into a storm sewer system, and to a method of decanting fluids on-route. 
       BACKGROUND 
       [0002]    So-called Vactor trucks and sweepers are used to maintain storm drains as part of a daily routine for municipalities and stormwater maintenance contractors. The equipment is essential for keeping trash and debris out of the stormwater system and is a primary line of defense for environmental protection. Stated simply, a Vactor truck uses vacuum force to suck debris from storm drains to remove debris. As the debris is sucked into the truck, a substantial amount of water is also sucked into the truck. The trucks tend to fill rapidly, most of the load is water and a smaller percentage is the debris that was removed from the storm drains. 
         [0003]    When the trucks are full they are typically driven to a treatment plant where the contents—the liquid and debris—are decanted into the treatment plant for processing. Vactor trucks typically follow a set route and the distance driven to the treatment plant is often significant—the treatment plants are rarely close to the route that the driver is following. 
         [0004]    Operating a Vactor truck is very costly. There is the upfront capital for the equipment, fuel to keep the equipment going, employee wages and the cost of disposal at the treatment facility. The high mileage driven by the trucks also takes a toll, not to mention the wear and tear on the vehicle, employee time traveling to the treatment plant and back to the scheduled route. 
         [0005]    There is a need therefore for equipment and methods that simplify and make more efficient the process of storm drain cleanout. 
       SUMMARY 
       [0006]    The present invention comprises an expansion ring that is designed to be installed in existing manholes so that a filter may be suspended in the manhole. The expansion rings and filters are installed in manholes at strategic locations on storm drain cleanout routes so that the full Vactor trucks can be decanted on-route instead of driving to a treatment facility. 
         [0007]    The expansion ring is adaptable to most pre-existing and new manholes. The ring has multiple adjustable expansion joints and plural bolts around the periphery of the ring that have pointed tips that bear into the sides of the manhole. The combination of the expansion joints and bolts allows the expansion ring to be securely affixed in the manhole. A filter basket assembly is suspended from the expansion ring into the manhole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The invention will be better understood and its numerous objects and advantages will be apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings. 
           [0009]      FIG. 1  is a side elevation and cross sectional view of the present invention, illustrating the expansion ring installed in a typical manhole with a filter of the type described in U.S. Pat. No. 8,221,632 suspended below the expansion ring. 
           [0010]      FIG. 2  is an upper perspective view of the expansion ring according to the present invention showing the expansion ring in isolation. 
           [0011]      FIG. 3  is a plan view of one of the plural retaining bolts used with the expansion ring, the bolt having a sharpened tip for bearing on the interior surface of the manhole. 
           [0012]      FIG. 4  is a perspective view of one of the plural expansion joints used with the expansion ring according to the present invention. 
           [0013]      FIG. 5  is a side elevation view illustrating an expansion joint and two retaining bolts. 
           [0014]      FIG. 6  is an upper perspective view of an alternative embodiment of the expansion ring according to the present invention, the illustrated expansion ring having a single expansion joint and a hinge in the ring opposite the expansion joint. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    With reference to the figures, an apparatus  10  according to the present invention is seen as comprising an expansion ring  12  that is designed to be installed in an existing manhole  100 . The manhole  100  is part of a storm drain system in a municipal sewer system and typically is located in a roadway. The manhole is of a conventional construction and is typically cylindrical and made of precast concrete. The manhole shown in  FIG. 1  has a metal ring  102  formed into the concrete sidewall  104  and the metal ring defines a lip  106  that supports a conventional grate  108 . It is to be understood that the present invention is designed to be installed in many different types of existing manholes including those without metal rings  102 . 
         [0016]    Turning now to  FIGS. 2 ,  3  and  4 , the expansion ring  12  is shown in isolation. The embodiment shown defines a circular ring member  14  that includes four curved or arcuate sections  16 ,  18 ,  20  and  21 , each attached to the adjacent section by an expansion joint  22  so that the combination of the four interconnected sections defines a circular member that, as detailed below, has a diameter that may be varied. The embodiment further illustrates four retaining bolts  50 , one in each of the sections  16 ,  18 ,  20  and  21 . 
         [0017]    The sections  16 ,  18  and  20  are curved L-shaped metallic sections that have a flattened, peripherally extending upper shelf portion  24  and a generally vertical side wall portion  26  through which the retaining bolts  50  extend and which defines the peripheral edge of the ring  12 . 
         [0018]    Adjacent sections  16 ,  18 ,  20  and  21  are attached to each other by the expansion joints  22  (described below) and a slip joint  28  defined by opposing metallic arms  30  and  32  welded onto the adjacent sections and which together define an intermeshing arrangement where the arm  30  of one section slips into a channel  31  defined by the arm  32  of the adjacent section to thereby allow the adjacent sections to move relative to one another yet remain stably connected. The slip joints thus define a stabilizing feature that allows the adjacent sections to be manipulated with the expansion joints while the sections are stable relative to one another. With reference to  FIG. 4 , arm  30  is welded to the interior portion of section  16 , to the lower surface opposite shelf  24 , and extends outwardly past the edge of the section toward adjacent section  18 . Arm  32  is welded to the interior portion of section  18 , to the lower surface opposite shelf  24  and extends outwardly past the edge of the section toward adjacent section  16 . Arm  32  is spaced apart from the material that defines shelf  24  to define the channel  31 . When sections  16  and  18  are assembled, arm  30  is inserted into channel  31  as indicated in the drawings to stabilize the two sections relative to one another, for example, during installation of the expansion ring  12  into a manhole  100  as detailed below. 
         [0019]    Each retaining bolt  50  is defined by a nut having a standard hex end  52  in the interior of the expansion ring  12 , a threaded shaft  54  that is threaded through a nut  56  welded to the interior of vertical side wall portion  26 . The retaining bolt  50  extends through the vertical side wall portion  26  with the distal end  58  of the retaining bolt  50  exposed to the exterior of the ring. The distal end  58  is pointed so that it may bear into the interior wall of the manhole  100  during installation. A lock nut  60  is threaded onto threaded shaft  54  between hex end  52  and nut  56  to act as a lock. 
         [0020]    Each expansion joint  22  is defined by a generally U-shaped turnbuckle  62  having one end  64  pivotally connected to a shaft  67  that is welded to the underside of the interior of shelf  24 —the opposite ends of arms  66  and  68  of the U-shaped turnbuckle  62  are integrally connected (as by welding) to a threaded member  70  having reversing threads as used in a conventional turnbuckle arrangement. A turnbuckle  62  as just described is attached to each end of each section  16 ,  18 ,  20  and  21  (i.e., two turnbuckles  62  per section) and adjacent turnbuckles are interconnected with a threaded shaft  72  that has its opposite ends threaded into adjacent threaded members  70  as shown in  FIG. 4 . A nut  74  is fixed on threaded shaft  72  near the middle of the shaft, between adjacent turnbuckles  62 , so that the shaft may be manipulated—rotated—with a wrench. The threads on shaft  72  on either side of nut  74  are reversed in orientation so that the shaft may be threaded onto the reversed threads of the two turnbuckles  62 . By rotation nut  74 , the shaft  72  is rotated and the adjacent sections  16  and  18  are either drawn together toward one-another, or driven away from one another, depending on the direction of rotation of the nut  74  (arrows A and B,  FIGS. 2 and 6 ). 
         [0021]    It will be appreciated that the diameter of expansion ring  12  is increased or decreased by adjustment of the expansion joints  22  as just described. As the diameter is adjusted, the slip joints  28  maintain the stable connection between adjacent sections  16 ,  18 ,  20  and  21 . 
         [0022]    An expansion ring  12  may include more than four sections and expansion joints  22 , or fewer, and may include more or fewer retaining bolts  50  than shown in the drawings. 
         [0023]    With returning reference to  FIG. 1 , the filter used in connection with the expansion ring described above may be of the type described in U.S. Pat. No. 8,221,632, Surface Water Filtration Device, the disclosure of which is incorporated herein in its entirety. Other filter types may also be utilized. The filter includes a suspending plate  80  that is circular and which rests on the shelf  24 . A filter basket assembly  82  is suspended on the suspending plate  80  through a central opening  84  in the suspending plate such that the filter basket assembly remains in the manhole  100 . 
         [0024]    The apparatus  10  may be of any appropriate size for the manhole  100  in which the apparatus is to be installed. While there are standard dimensions for manholes, there is variability in the interior measurements, diameters, etc. Accordingly, the expansion ring  12  may be made in various sizes. An appropriately sized expansion ring is installed in a manhole  100  by inserting the ring  12  with the retention bolts  50  in their retracted positions (i.e., with the bolts loosened such that the pointed distal ends  58  are near the vertical side wall portion  26  and extending past the side wall only minimally if at all). The diameter of the expansion ring  12  should be slightly smaller than the diameter of the manhole when the expansion joints  22  are in their retracted position—that is, when the diameter of the expansion ring is near its minimum. 
         [0025]    The expansion ring  12  is inserted into the manhole  100  in a position as shown in  FIG. 1  and the expansion joints  22  between sections  16 ,  18 ,  20  and  21  are sequentially expanded by rotation of nuts  74  to increase the overall diameter of the expansion ring  12  until the vertical side wall portion  26  approaches or abuts the interior wall of the manhole. The slip joints  28  maintain the orientation of the sections  16 ,  18 ,  20  and  21  during the installation and keep the adjacent sections stably connected to one another regardless of the positions of the expansion joints. The retaining bolts  50  are then manipulated with a wrench to extend and drive the pointed distal ends  58  into the side wall of the manhole. Because the distal ends  58  are pointed, as the retaining bolts are driven into the side wall of the manhole the pointed distal ends  58  bear into the side wall of the manhole to provide a secure connection. The bolts  50  are all rotated until the distal ends are firmly seated in the side wall of the manhole. The lock nuts  60  are then tightened to secure the position of the expansion ring  12 . 
         [0026]    At this point the filter basket assembly  82  may be installed as described above. 
         [0027]    When assembled in this manner, fluid from a Vactor truck may be decanted into the manhole by emptying the liquid into and through the filter basket assembly. Filtered water flows through the basket assembly and solids and other components removed from the water are retained in the filter basket assembly (which may be removed, cleaned and replaced as necessary). 
         [0028]    In addition to the apparatus described above, the present invention further contemplates a method of collecting storm water from storm drain systems and decanting the collected storm water—the method enabled by the apparatus. Specifically, the method involves the identification of plural clean-out locations to define a clean-out route. The clean-out route is a set route that a Vactor truck or sweeper follows and which has plural clean-out locations on the route. Each clean-out location is an individual manhole or storm drain such as a curb inlet vault that is to be cleaned by the Vactor truck. 
         [0029]    Having established the clean-out route, plural apparatuses  10  are installed in the manholes at selected clean-out locations on the route. The manholes in which the apparatus  10  are installed are referred to herein as the “decanting locations.” Typically, the decanting locations are strategically located on the clean-out route so that they are separated from one another by multiple other clean-out locations—that is, multiple storm drains that are being cleaned on the route. The decanting locations are located so that there are enough clean-out locations between each decanting locations so that the Vactor truck is full and ready to be emptied—decanted—at each decanting location. By following this method, the Vactor truck is emptied along the route and the fluid from the truck that normally would be emptied at a distant treatment facility is filtered on-route into the storm drain system. This method eliminates the need to drive the truck to the treatment facility every time it is full, with significant savings in fuel, labor and wear and tear on the equipment. 
         [0030]    An alternative embodiment of an expansion ring  200  is illustrated in  FIG. 6 . Expansion ring  200  functions in the same manner as apparatus  10  described above and installed in a manhole  100  in the same manner. However, the expansion ring comprises only two sections  202  and  204  having first ends attached to one-another with a hinge  206  and opposite ends interconnected with an expansion joint  22  identical to those described above. It will be appreciated that with an expansion ring  200  that has two sections such as shown in  FIG. 6 , each section  202  and  204  defines an arc of about 180 degrees. On the other hand, with an expansion ring  12  as shown in  FIG. 2  that has four sections  16 ,  18 ,  20  and  21 , each section defines an arc of about 90 degrees. 
         [0031]    While the present invention has been described in terms of a preferred embodiment, it will be appreciated by one of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims.