Abstract:
A filtration apparatus includes a filter element disposed at a 45 degree angle defining an upper chamber for solids and a lower chamber for liquid. A trough is disposed at the lower end of the filter element. The floor of the trough funnels toward a central drain and an overflow drain is located approximately 8 inches above the trough floor. The lower chamber is provided with a drain for recirculating water to a sprayer above the filter element and is also provided with an overflow drain approximately 8 inches above the floor.

Description:
This application is related to co-owned U.S. Pat. No. 5,575,913, the complete disclosure of which is hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a filtration apparatus for separating solid particles from a liquid. More particularly, the invention relates to filtration apparatus for removing particulate contaminants from commercial laundry waste water and to methods for accomplishing the same. 
     2. State of the Art 
     State and local governments across the country as well as the federal government have enacted new laws or expanded existing laws to reverse or limit the threat of environmental pollution. These environmental laws are typically directed toward commercial enterprises which create various wastes streams as a by-product of manufacturing products or providing services. The commercial laundry industry and particularly commercial laundromats are specifically affected by environmental laws which limit the amount of suspended solids or particulate contaminants in commercial laundry waste water which can be discharged into the environment. Particulate contaminants in commercial laundry waste water generally consist of lint, hair, dirt and soap scum. To meet the requirements of current environmental laws, the amount of particulate contaminants in commercial laundry waste water must be reduced to an acceptable level before it is discharged into the ground water and/or municipal sewage system. 
     Co-owned U.S. Pat. No. 5,350,526 discloses a filtration apparatus specifically intended for removing particulate contaminants from commercial laundry waste water. It has at least one porous mesh-like filter bag coupled between an inlet manifold for receiving waste water containing particulate contaminants and an outlet manifold for discharging the particulate contaminants separated from the waste water. The filter bag is agitated by a paddle, so as to prevent the mesh-like material of the filter bag from being clogged. The apparatus is capable of trapping particles as small as 5 microns depending on the filter bag mesh. Those skilled in the art will appreciate that the finer the mesh the more slowly the water will be filtered. One of the challenges in designing a filter for commercial laundry waste water is to be able to accommodate a flow rate of about 12,500 gallons per day. 
     Co-owned U.S. Pat. No. 5,575,913 discloses a filtration apparatus having a housing, a filter element, an inlet, a first discharge outlet and a second discharge outlet. The housing includes a bottom and an upwardly extending surrounding wall. The filter element is disposed in the housing and spans the surrounding wall with the filter element spaced above the bottom of the housing to define an upper chamber and a lower chamber, and the filter element being angled, preferably 45 degrees from the horizontal, so that one end of the filter element is lower relative to the other end. The inlet is in fluid communication with the upper chamber for receiving waste water containing particulate contaminants. A first discharge outlet is in fluid communication with the lower chamber for discharging filtered waste water. The second discharge outlet is in fluid communication with the upper chamber adjacent the lower end of the filter element for discharging filtered particulate contaminants. Particulate contaminants are removed from the filter element by a water spray. The apparatus is capable of trapping particles about 50 microns in diameter. 
     The apparatus disclosed in the &#39;913 patent, while a vast improvement over the prior art, can still be improved. Challenges still remain regarding the build up of solids on the filter element; the removal of lint, hair, and other similar solids from water; water overflow through the filter element; hardening of dried solids within the apparatus; the failure of solids to be drained from the apparatus; and the need for regular human intervention. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved filtration apparatus and method for separating and removing particulate contaminants from a relatively large continuous flow of laundry waste water for discharge of the filtered waste water into the environment, i.e., ground water and/or municipal sewage system. 
     It is another object of the invention to provide such a filtration apparatus having a filter element for separating particulate contaminants from laundry waste water in which the separated particulate contaminants can be easily and quickly manually or automatically removed from the apparatus without injuring or removing the filter element. 
     It is still another object of the invention to provide such a filtration apparatus wherein hair, lint, sand and other collected solids are quickly and efficiently discharged without manual intervention. 
     It is yet another object of the invention to provide such a filtration device wherein collected solids are kept in a fluid suspension for easy fluid discharge. 
     It is also an object of the invention to provide such a filtration device wherein water overflow through the filter element is prevented. 
     It is another object of the invention to provide such a filtration device wherein water used to spray the filter element is conserved. 
     It is still yet another object of the present invention to provide such a filtration apparatus that is easily and inexpensively manufactured; highly efficient in operation, and which requires little lifetime maintenance. 
     In accord with these objects which will be discussed in detail below, the filtration apparatus of the present invention includes a housing, a filter element, an inlet, a first discharge outlet and a second discharge outlet. The housing includes a bottom and an upwardly extending surrounding wall. The filter element is disposed in the housing and spans the surrounding wall with the filter element spaced above the bottom of the housing to define an upper chamber and a lower chamber, and the filter element being angled, preferably 45 degrees from the horizontal, so that one end of the filter element is lower relative to the other end. A wall is located at the lower end of the filter element to provide a trough adjacent to the lower chamber to collect water with suspended particles. The inlet is in fluid communication with the upper chamber for receiving waste water containing particulate contaminants. The first discharge outlet is in fluid communication with the lower chamber for discharging filtered waste water. The second discharge outlet is in fluid communication with the trough for discharging filtered particulate contaminants suspended in water. Particulate contaminants are removed from the filter element and drained into the trough by a water spray located above the filter element. 
     According to the preferred embodiment, the trough discharge outlet is located in the middle of the bottom of the trough and the bottom of the trough is tapered downward to the discharge outlet. An overflow discharge is also located in the trough to prevent water from overflowing above the filter element and floating solids back onto the filter element. The overflow discharge is preferably terminated with a T-fitting so that water is drained from below the surface. The lower chamber is also provided with a second discharge for recycling filtered water to the spraying system. 
     The filtration unit according to the invention has the capacity to filter larger volume of water more efficiently, and requires little or NO human physical participation. The addition of the trough creates a filter system with its own solid waste storage capabilities. This creates longer filter runs without the need for manual or electrically timed discharge, this means less energy used and less manual attention to the unit. 
     The filter screen is never compromised with the collected solids on the mesh screen itself Thus the filter screen is always free from solids. This allows the filter the ability to handle a continuous higher volume and will always remain at its maximum use and potential. 
     The unit will also supply itself with its own feed water for the action of spraying down the screen. 
     Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentarily-illustrated perspective view of the filtration apparatus embodying the present invention with portions broken away to show internal construction; 
     FIG. 2 is a fragmentarily-illustrated side view of the filtration apparatus shown in FIG. 1; 
     FIG. 3 is a schematic side elevation view of the overflow drain; and 
     FIG. 4 is a schematic side elevation view of the relative locations of the four discharge outlets of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to the drawings, and in particular to FIG. 1, a filtration apparatus  10  according to the invention receives laundry waste water discharge from a number of commercial laundry washing machines via pipe  100 . The filtration apparatus  10  generally includes a housing  20 , a filter element  40 , a laundry waste water inlet having an open top end  64 , a filtered waste water discharge outlet  62 , particulate contaminate outlet  60  and a sprayer  70 . 
     The housing  20  includes a bottom  22  and an upwardly extending surrounding wall  24 . Specifically, housing  20  has a generally open box-like configuration in which bottom  22  is rectangularly shaped and upwardly extending side wall  24  consists of a front wall  25 , a rear wall  26  and two side walls  27 . It is appreciated that the bottom  22  of housing  20  can be circularly or squarely shaped. Preferably, housing  22  is fabricated from a rust resistant material such as a plastic material. 
     The filter element  40  is disposed in the interior of housing  20 , spanning between the interior surface of surrounding wall  24 . Generally, the filter element  40  consists of an interwoven filtering material  42 , preferably a micro screen such as a monofilament mesh fabricated from nylon, and a surrounding frame  44 . The frame  44  provides a border around interwoven filtering material  42  and which serves as structural support for interwoven filtering material  42 . Such factors as the amount and consistency of the laundry waste water flow rate, and size and amount of solid particulate contaminants, etc. will dictate the desired mesh size of the interwoven filtering material  42 . Desirably, the interwoven filtering material  42  has a mesh size ranging from about 70 microns to 25 microns. Preferably, the frame  44  is fabricated from a rust resistant metal such as aluminum. 
     The housing  20  includes a support  30  attached to the interior surface of surrounding wall  24  for providing support to filter element  40 . Specifically, the support  30  includes a lower front support  35 , an upper rear support  36 , and two side supports  37  which are angled from lower front support  35  to the upper rear support  36 . Preferably, the support  30  includes a continuous rubber material which forms a seal with frame  44  of the filter element  40  so that, as explained below, particulate contaminants will not pass around frame  44  but will be retained on interwoven filtering material  42 . 
     Preferably, the housing  20  includes a plurality of releasable locking means  47  for releasably locking the frame  44  of the filter element  40  in a fixed position in the housing  20 . The releasable locking means  47  may comprise pivotable latch-like arms mounted on each of the sidewalls  25 ,  26  and  27  for movement between a release position (shown in phantom in FIG. 1) and a locking position with respect to the frame  44 . In the latter position, it either closely abuts the frame  44  or is received within a corresponding slot  51  in frame  44 . 
     The filter element  40  is disposed within the interior of housing  20  and spaced apart from bottom  22  forming an upper chamber  50  (unfiltered space) and a lower chamber  52  (filtered space). The filter element  40  is angled so that a lower end  46  is lower relative to an upper end  48 . Preferably, the filter element  40  is angled at between about 30 degrees and 60 degrees from the horizontal. Most preferably, filter element  40  is angled at about 45 degrees from the horizontal. 
     The upper edge  28  of the surrounding wall  24  forms waste water inlet  64 , in fluid communication with upper chamber  50 , for receiving laundry waste water containing particulate contaminants from discharge pipe  100 . It will be appreciated that the housing  20  can include a cover or lid supported on upper edge  28  of surrounding wall  24  and provided with a inlet opening for receiving laundry waste water containing particulate contaminants. 
     A filtered waste water discharge outlet  62 , in fluid communication with lower chamber  52 , provides for discharge of collected filtered waste water in lower chamber  52 . Filtered waste water discharge outlet  62  can be positioned over a floor drain or connected to a conduit for discharge of the collected filtered waste water into the ground water and/or municipal sewage system. According to one aspect of the invention, and as seen best in FIGS. 2 and 4, the filtered waste water discharge outlet  62  extends upward from the bottom  22  of housing  20  for about eight inches. This creates a reservoir of filtered water  113  inside the chamber  52 . A drain  71  is located approximately one inch from the floor  22  of the chamber  52 . The drain  71  provides access to the reservoir of filtered water which may be recycled to the sprayer  70  with the aid of a pump (not shown). 
     According to another aspect of the invention, a wall  49  seen best in FIGS. 2 and 4, is disposed parallel to the front wall  25  between the floor  22  and the bottom end  46  of the filter element to create a trough separated from the lower chamber  52 . The particulate contaminate discharge outlet  60 , in fluid communication with the trough of the upper chamber  50 , is preferably centrally located. As seen best in FIG. 1, the floor  29  of the trough preferably funnels toward the centrally located discharge  60 . 
     According to yet another aspect of the invention, a particulate contaminate discharge overflow outlet  61  is disposed in side wall  27  adjacent lower end  46  of filter element  40 . As seen best in FIG. 3, the outlet  61  terminates in a T-fitting  21  so that liquid is discharged from below the surface  110  of the waste water  111  and the collected film of solid waste  112  (see arrow) and recycled back to the waste water inlet pipe  100  via a pump (not shown). 
     As seen in FIGS. 1 and 2, spray means  70  for discharging a spray of liquid, preferably water under pressure from a suitable source (not shown), across an upper surface  45  of filter element  40  flushes or causes particulate contaminants collected on upper surface  45  of filter element  40  to move toward lower end  46  into the trough and toward particulate contaminate discharge outlet  60 . Specifically, the spray means  70  includes a pair of pipes  72  each extending horizontally along the interior of housing above filter element  40 . Extending from each pipe  72  are L-shaped pipes  74  having a pair of nozzles  76 . In addition, nozzles  78  are attached at each end of pipe  72 . Preferably, pipes  72  and L-shaped pipes  74  are fabricated from a plastic material such as polyvinyl chloride (PVC). It will be appreciated that one skilled in the art could provide other equally suitable alternative configurations for positioning the spray nozzles above filter element  40  to cause accumulated particulate contaminants on upper surface  45  of filter element  40  to move toward lower end  46  and toward particulate contaminate discharge outlet  60 . 
     Spray means  70 , as explained below, can be operated to prohibit particulate contaminants from accumulating on upper surface  45  of filter element  40  and clogging the interwoven filtering material  42  of filter element  40  by either constantly supplying a spray of liquid during operation or alternatively at periodic intervals. Removal of particulate contaminants from filtering apparatus  10  can be accomplished manually or preferably by coordination of spray means  70  and a discharge valve  80 . Specifically, discharge valve  80  is in fluid communication with particulate contaminate discharge outlet  60  and is normally closed so that laundry waste water is not carried out particulate contaminate discharge outlet  60  during operation. When the filter element  40  has and excessive amount of accumulated particulate contaminants thereon, the discharge valve  80  can be opened and the accumulated particulate contaminants can be flushed out by activation of spray means  70 . Preferably, discharge valve  80  is operated by a conventional solenoid  82  connected by an electrical wire or lead  84  to a conventional timer  86  for automatic periodic flushing and discharge of the collected particulate contaminants in conjunction with spray means  70  by concurrent control of valve  92  operated by solenoid  96  also connected via wire  94  or the like to timer  86 , the latter of which would be connected to an electrical outlet. As mentioned above, water for the sprayer  70  is preferably obtained from outlet  71  provided in the lower chamber  52 . 
     The operation of the present invention will be understood as follows: laundry waste water from washing machines is introduced into the filtration apparatus  10  by laundry waste water discharge tube  100  as shown by the solid arrow in FIG.  1 . The laundry waste water is deposited on upper end  48  of upper surface  45  of filter element  40 . Filtered waste water, shown as dashed arrows in FIG. 2, passes through the filter element  40  while particulate contaminants accumulate on upper surface  45  of the filter element  40 . 
     The unique design of filtering system  10  takes advantage of gravitational forces, and hydraulic forces from subsequent discharge of laundry waste water to naturally cause accumulated particulate contaminants on upper surface  45  of filter element  40  to move downward along upper surface  45  toward lower end  46  and into the trough defined by wall  49 . In addition, spray means  70  can be operated continuously or periodically to aid in causing accumulated particulate contaminants on upper surface  45  of filter element  40  to move downward along the upper surface toward lower end  46  and into the trough. 
     Removal of particulate contaminants from upper chamber  52  of housing  20  may be accomplished manually or preferably by coordination of spray means  70  and discharge valve  80 . Specifically, spray means  70  is operated to supply a spray of liquid continuously during operation or at periodic intervals in coordination with discharge valve  80 . Discharge valve  80  is attached to particulate contaminate discharge outlet  60  and is normally closed (unless continuous spraying is used) so that waste water is not carried out particulate contaminate discharge outlet  60  during normal filtering operation. When the trough and filter element  40  fills up with excessive particulate contaminants, discharge valve  80  can be opened and the accumulated retained particulate contaminants can be flushed out. Preferably, as indicated above, water supply valve  92  and discharge valve  80  are operated by conventional solenoids  82 ,  96 , respectively, connected by wires  84 ,  94 , respectively, to a conventional timer  86  for concurrent operation and automatic periodic flushing and discharge of the collected particulate contaminants. As mentioned above, the overflow drain  61  recirculates partially filtered waste water to the inlet of the filtration apparatus. 
     Various modifications can be made as will be apparent to those skilled in the art. For example, while only one row of pipes  74  and nozzles  76  are shown, two or more may be provided to facilitate contaminant discharge and cleaning of the filter or screen  40 . However, the various parts shown in the drawing are commercially available so that the unit can be made economically. 
     Furthermore, although only one unit is shown in the drawings, multiple units could be employed in series having differently- and decreasingly-sized screen mesh openings to achieved a tiered screening effect. 
     The improvements provided by the present invention can be summarized in part as follows: the location of the wall  49  to define the trough, the location of the drain  60  in the center of the trough, the funnelling of the floor  29  of the trough, the provision of the T-drain  21 / 61  in the trough, the location of the raised drain  62  in the chamber  52  to provide a reservoir of filtered water, and the location of the drain  71  for tapping the reservoir. It will be appreciated that many of these improvements may be used either alone or in combination with each other. 
     It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.