Abstract:
An arrangement for cleaning algae and other debris from the various surfaces within a sedimentation tank includes one or more mechanized rotating scrubbing brushes. In contrast to conventional arrangements that use rectangular, non-mechanized brushes, the rotational brush elements of the present invention are more effective and efficient at removing a larger quantity of material from the various interior wall surfaces (e.g., baffle, weir, spillway, etc.) within the sedimentation tank.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a cleaning arrangement for a sedimentation tank, such as a water or wastewater treatment tank and, more particularly, to a cleaning device that utilizes a mechanized rotary brush arrangement to effectively remove algae and other debris from various surfaces of the tank.  
       BACKGROUND OF THE INVENTION  
       [0002]     A typical wastewater treatment facility includes clarifiers or settling tanks to accomplish separation of solids from liquid. The settled solids are removed from the bottom of the tank as sludge and the clarified liquid above is discharged into an effluent trough or launder. Tank geometries and configurations vary widely but are most commonly circular with the continuous flow of influent water entering near the center of the tank and the discharge of clarified effluent water occurring near the tank periphery. Effluent troughs and launders are generally equipped with weirs to control the flow of the clarified supernatant. In tanks where surface scum is prevalent, scum baffle plates are often provided adjacent to the weirs and the displaced water is forced to flow under a baffle plate that blocks floating scum. Once over the weir, the water flows in an effluent trough or launder to a discharge pipe and on to the next unit in the treatment process. Ultimately, the clean effluent water is disinfected and made sufficiently safe to discharge into a river or stream.  
         [0003]     As is known in the art, the outdoor exposure of the treatment tanks in direct sunlight encourages the unwanted growth of algae. This growth is most prevalent one the baffle, weir, spillway and clean water flow channel areas of the treatment tank. Disadvantageously, algae growth on these members inhibits the flow of clean water from the tank. Further, the algae can be carried in thick masses and high concentrations in the clean water being discharged from the final treatment tank. When this occurs, large concentrations of chlorine are required to kill the algae. Since chlorine is relatively expensive, it is preferred to prevent the buildup of algae.  
         [0004]     Removing the algae from the baffle, weir, spillway and clean water flow channel has primarily been accomplished in the past by scrubbing the tank structure by hand with long-handled brushes. Since the final treatment tanks are usually quite large, such a cleaning process becomes considerably tedious and labor-intensive.  
         [0005]     One prior art apparatus for improving algae removal is disclosed in U.S. Pat. No. 4,830,748 issued to Ford W. Hall on May 16, 1989. The Hall cleaning apparatus comprises a series of rectangular cleaning brushes that are attached through support arms to a main frame member. The main frame member is attached to a conventional skimmer blade. Since the skimmer blade is designed to slowly revolve, the cleaning brushes will also move around the tank. Thus, instead of a worker manually scrubbing algal growth surfaces with a broom, an automated set of brooms essentially moves around the surfaces of the tank. A self-propelled version of this apparatus (for use in arrangements without a skimmer blade) is the subject of U.S. Pat. No. 4,978,447, issued to Ford W. Hall on Dec. 18, 1990. A remaining problem with both of these arrangements, however, is that the brushes are non-mechanized (i.e., a “static” brush design), and a significant amount of algae and other debris may build up on the brush surfaces, thus lessening the cleaning ability of the system. Moreover, the rectangular brush design is not considered as the most effective cleaning arrangement.  
         [0006]     Thus, a need remains in the prior art for a mechanized arrangement for effectively cleaning algae and other debris from water and wastewater treatment tanks.  
       SUMMARY OF THE INVENTION  
       [0007]     The need remaining in the prior art is addressed by the present invention, which relates to a cleaning arrangement for a sedimentation tank, such as a water or wastewater treatment tank and, more particularly, to a cleaning arrangement that utilizes a mechanized rotary brush arrangement (i.e., a “dynamic brush”) to effectively remove algae and other debris from various surfaces of the tank.  
         [0008]     In accordance with the present invention, a sedimentation tank cleaning apparatus comprises a single rotary brush or a series of rotary brushes attached to a support arm. Each brush is mechanized (either individually or as a group) to rotate at a speed sufficient to effectively remove algae and other debris from the various surfaces within the tank structure. Different sizes of brushes may be used along various surfaces, as need be. Moreover, different rotation speeds may be used for different brush locations. For example, a faster rotation may be used along the baffle and weir, where a larger amount of algae and debris will collect. More aggressive scrubbing in these areas will serve to prevent a significant amount of algae and debris from crossing the spillway into the launder area.  
         [0009]     Other and further embodiments and advantages of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     Referring now to the drawings, where like numerals represent like parts in several views:  
         [0011]      FIG. 1  contains a partial, cut-away isometric view of an exemplary prior art tank cleaning apparatus;  
         [0012]      FIG. 2  contains a partial, cut-away isometric view of an exemplary rotary brush tank cleaning apparatus formed in accordance with the present invention;  
         [0013]      FIG. 3  is a cut-away side view of the arrangement of  FIG. 2 ;  
         [0014]      FIG. 4  is an enlarged illustration of an exemplary motorized brush for use in the various embodiments of the present invention;  
         [0015]      FIG. 5  illustrates an alternative embodiment of the present invention, in a partial, cut-away isometric view; and  
         [0016]      FIG. 6  is a cut-away side view of the arrangement of  FIG. 5 . 
     
    
     DETAILED DESCRIPTION  
       [0017]     Prior to describing the improvements in the cleaning of water or wastewater treatment sedimentation tanks in accordance with the present invention, it is considered helpful to review the state-of-the-art cleaning apparatus. In particular,  FIG. 1  illustrates an exemplary prior art apparatus  10 , including a set of non-mechanized or “static” scrubbing brushes that are used to dislodge algae and other debris from surfaces within the tank. As shown, prior art apparatus  10  includes a main frame member  12  that is attached to a skimmer blade  14  by using a mounting bracket  16 . During operation, skimmer blade  14  slowly revolves around the water treatment tank (as indicated by the arrows in  FIG. 1 ) so as to direct any floating debris into a scum trough. In this prior art arrangement, therefore, the scrubbing brushes that are attached to main frame member  12  will revolve in a similar manner.  
         [0018]     Water treatment tank  20  (which is nominally circular in form, with only a portion being illustrated in  FIG. 1 ) includes an interior baffle  22  and a weir  24  that function as described above to control the discharge of clarified water exclusive of surface scum. As shown, weir  30  is contiguous with a spillway  26 , where spillway  26  is configured to include a downwardly sloping outer wall  28 . Ultimately, the fully treated water will flow into outer clean water channel  30  of tank  20 .  
         [0019]     In operation of prior art apparatus  10 , a first set of brushes  32  is provided to scrub/clean baffle  22  and weir  24 , including individual brushes to clean the inner surface of baffle  22 , the outer surface of baffle  22  and the inside surface of weir  24 . A second set of brushes  34  is used to clean the outer surface of weir  24  and spillway  26 , including a brush mounted in a sloping position to clean sidewall  28  of spillway  26 . Lastly, a third set of brushes is used to scrub clean water channel  30 , with separate brushes for the sidewalls and bottom surface of channel  30 . As mentioned above, while a degree of improvement is achieved with this prior art apparatus (as compared to manual cleaning processes), various amounts of algae and other debris may be lodged against the static brushes, resulting in ineffective cleaning.  
         [0020]      FIGS. 2 and 3  illustrate a first embodiment of the present invention that provides an improvement over prior art apparatus  10  as shown in  FIG. 1 . In particular, apparatus  40  is formed to include mechanically-driven rotary brushes to more effectively clean the various surfaces within the treatment tank. For the sake of simplicity, the same treatment tank  20  as described above is illustrated in  FIG. 2 , with the only change being the replacement of prior art apparatus  10  with inventive cleaning apparatus  40  formed in accordance with the present invention. Referring to  FIG. 2 , cleaning apparatus  40  is illustrated as including a support assembly  42 , which extends outward from the center of the tank (not shown) toward clean water channel  30 . In the particular embodiment of  FIG. 2 , assembly  42  includes a first support member  44  for supporting and driving a first plurality of mechanically-driven rotary brushes and a second support member  46  for supporting and driving a second plurality of mechanized rotary brushes.  
         [0021]      FIG. 4  contains an isometric view of an exemplary mechanized rotary brush  100  that may be used in the exemplary embodiment of the present invention as illustrated in  FIGS. 2 and 3 . As shown in  FIG. 4 , brush  100  comprises a bristle assembly  110  disposed at the termination thereof, with bristle assembly  110  configured to rotate (in this case, in a counterclockwise direction). The rotation of bristle assembly  110  is controlled by a motor  120  mounted directly over and attached to bristle assembly  110 . Motor  120  is sized so as to provide the desired amount of torque required to provide the rotational movement. A control signal for motor  120 , as well as the electrical, pneumatic or hydraulic power necessary to drive motor  120 , are provided as inputs from a remote source (not shown). A handle  130  may be used as a conduit and thereafter coupled to motor  120 . In some embodiments of the present invention, the speed of motor  120  is controllable, so as to adjust the rotational speed of bristle assembly  110 .  
         [0022]     It is to be understood that the inclusion of motor  120  on brush  100  is exemplary only. Various other arrangements may be used that include the provision of a single, centralized motor that is coupled to each separate bristle assembly through an interconnection, such as a pulley system. While more efficient in terms of the reduction of motors and power required, the single-motor embodiment lacks the ability to modify the rotational speed of the individual brushes. However, either arrangement may be used in accordance with the present invention.  
         [0023]     With this understanding of the particular brush assembly, it is possible to understand the operation of the present invention by reference to  FIGS. 2 and 3 . Referring again to  FIG. 2 , first support member  44  is illustrated as providing power and movement to a first plurality of mechanically-driven rotary brushes including an inner baffle wall cleaning brush  50 , an inner weir wall cleaning brush  52 , an outer weir wall cleaning brush  54 , and a pair of clear water channel floor cleaning brushes  56  and  58 . It is to be understood that this particular arrangement and distribution of brushes along first support member  44  is exemplary only, and that virtually any number and arrangement of mechanized brushes may be used. In its simplest form, a single mechanized rotary brush may be used alone or in combination with the “static” brushes of the prior art. The rotary brush or brushes can also be moved manually from one cleaning surface to another. Another embodiment of the present invention (not shown) involves an additional automated mechanism to move the brush or brushes from surface to surface.  
         [0024]     In accordance with the present invention, the necessary power and control signals are fed along first support member  44  and into the individual motors  120  of each brush assembly  100 . Elements  110 ,  120  and  130  of an exemplary brush (as discussed above in association with  FIG. 4 ), are particularly referenced in association with brush  56  in  FIG. 2 . It is to be understood that each individual brush in the arrangement of  FIG. 2  contains similar elements.  
         [0025]     Second support member  46 , as shown in  FIG. 2 , provides power and movement to a second plurality of mechanized rotary brushes. In this particular embodiment, second support member  46  is shown as coupled to an outer baffle wall cleaning brush  60 , a spillway cleaning brush  62 , an angled spillway brush  64  and a pair of channel wall cleaning brushes  66  and  68 .  
         [0026]     The cut-away side view of  FIG. 3  clearly illustrates the location of the various individual mechanized rotary brushes with respect to the various surfaces in water treatment tank  20 . Particularly evident in this view is the angular placement of brush  64 , so as to accommodate the downwardly sloping face  28  of spillway  26 . The utilization of the set of brushes  56 ,  58 ,  66  and  68  along the surfaces of clear water channel  30  are considered to be more than sufficient to remove any remaining algae and debris that collects in this outermost region. As with the arrangement and disposition of brushes along first support member  44 , it is to be understood that the various brushes included along second support member  46  may vary, as need be. Indeed, it is to be understood that various other support arrangements, using fewer or more support arms, may be employed, as long as the entire assembly is capable of rotational motion around the tank while providing rotational energy to the various brushes.  
         [0027]     Thus, in accordance with the present invention, the application of electrical, pneumatic or hydraulic power signals along first and second support members  44 ,  46  energizes the individual motors associated with each of the illustrated rotary brushes. Upon activation, the bristle assembly will rotate at a predetermined speed to provide efficient cleaning. In one embodiment, a common control/power signal is used for the entire combination of brushes. Alternatively, different brushes may be coupled to separate power/control leads so as to separately adjust the rotational speed of each brush and tailor the scrubbing ability of each brush for its particular use (i.e., scrubbing the weir vs. scrubbing the clear water channel).  
         [0028]      FIGS. 5 and 6  illustrate an alternative embodiment of the present invention that utilizes an alternative orientation of the brushes, resulting in the use of fewer brushes and requiring only a single support arm. As with the embodiment discussed above, separate motor elements (or a single motor with a pulley arrangement) are used to provide rotational motion to each brush. Referring to  FIG. 5 , inventive scrubbing arrangement  70  includes a single support arm  72 , with a plurality of separate brushing elements disposed along support arm  72 . In particular, a first brush  74  is disposed to clean the inner wall of baffle  22 . A second brush  76  is disposed to clean both the outer wall of baffle  22  and the inner surface of weir  24 , where the scrubbing material of brush  76  is appropriately sized so as to contact both surfaces (see also the cut-away side view of  FIG. 6 ). A third brush  78  is used to clean spillway  26 , with an additional brush  80  used to scrub angled surface  28  of spillway  26 . Inasmuch as brush  80  is used to clean only one surface, a traditional bristled brush may be used. Lastly, a final brush  82  is disposed within clear water channel  30  and used to clean the bottom surface, as well as the side surfaces, of the channel. Referring to  FIGS. 5 and 6 , brush  82  is sized such that the bottom surface of brush  82  will scrub the floor of channel  30 , with the outer periphery of brush  82  used to scrub the sidewalls of channel  30 . As with the embodiment of  FIGS. 2 and 3 , each brush in scrubbing arrangement  70  may include an individual motor to impart rotational motion to the scrubbing elements. Further, the speeds may be varied (as needed) to control the desired degree of cleaning.  
         [0029]     While this invention has been described fully and completely with special emphasis upon preferred embodiments, it should be understood that various modifications and alterations may be made to the particular brush and/or support mechanism and remain within the spirit and scope of the present invention. Since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, and fall within the scope of the invention.