Abstract:
A product that is an apparatus for removing debris from water containing such debris using a perforated plate, a backer plate, and a skimmer, positioned adjacent the back of the perforated plate to provide a means of removing debris from the perforated plate without scraping the debris from the perforated plate, the skimmer bar and the backer plate being synchronized in their movement.

Description:
This application is a utility application claiming priority from U.S. Provisional patent application Ser. No. 61/275,657, filed on Sep. 2, 2009 
    
    
     The invention disclosed and claimed herein deals with a product that is an apparatus for removing debris from water containing such debris. 
     The essence of the invention is the use of a perforated plate and a backer plate positioned adjacent the back of the perforated plate to provide a means of removing debris from the perforated plate without scraping the debris from the plate. 
     BACKGROUND OF THE INVENTION 
     Submerged membrane bioreactors are one of the fastest growing treatment methods in wastewater. However, as is typical of all wastewater treatment processes, it is often the effectiveness of the preliminary liquids/solids separation operation, early in the influent journey that determines the efficiency of downstream processes. 
     Membrane bioreactors combine key aspects of the activated sludge treatment process with a physical membrane liquids/solids separation operation. The membrane component uses low pressure microfiltration or ultra filtration membranes to eliminate the need for clarification and tertiary filtration. Generally, the membranes are immersed in the aeration basin, although some applications use a separate membrane tank. 
     Aging infrastructure, more stringent effluent requirements and changing population demographics have driven dramatic growth in membrane bioreactors both in North America and throughout the World. Their increasing popularity results from the ability of bioreactor technology to achieve filtration at the micron level, as well as its ability to deliver high quality effluent in considerably less space than a conventional wastewater treatment plant. 
     However, when planning a bioreactor based treatment plant, one must balance preliminary liquids/solids separation options with issues such as cost, footprint, and energy consumption. Even though membrane bioreactors technology is continuing to evolve and make improvements in the cost-of-ownership equation, today it is widely recognized that the cost of building and operating a membrane bioreactor is typically higher than that of conventional processes. This additional cost is often mitigated, however, by the proven benefits of membrane bioreactors. 
     While there are several types of membrane units, each depend on the preliminary liquids/solids separation operation of mechanical screening. Membranes are particularly vulnerable to non-biological suspended solids. These solids are a natural part of wastewater and arrive at the treatment facility in the form of trash, hair, plastics, rags, and other physical contaminants. Such contaminants cause fouling or blockages as well as matting among the membrane fibers. The results of this fouling can range from increased energy consumption and permanent damage to the membrane, causing its removal from service. 
     Fouling also causes other compromises in operation capabilities, including restrictions to processing capacity, costs and time for backwashing, and plant downtime when off line for replacement or maintenance. It is the screening system that typically accounts for less than three one-hundredths of the membrane bioreactor investment that must remove these potentially damaging physical contaminates from the process prior to introduction of the flow into the membrane tank. It is the screen that must ensure material capture without bypassing or carryover to the downstream and it is the screen and its efficacy that determines the demand for downstream maintenance. 
     The perforated plate of the instant invention mitigates the problems of current perforated plate prior art devices. For example, the perforated plate of this invention does not use any dynamic seals that are subject to wear and failure. Seal failure results in downstream contamination which causes tangling or fouling of sensitive membrane filters. The orientation of the perforated plate of this invention to the flowing water in the water channel provides an efficient and simple installation and provides a passive cleaning mechanism that eliminates the need for maintenance intensive brushes 
     Thus, it would be valuable to have a screening system that would not have the problems set forth above. 
     THE INVENTION 
     What is disclosed and claimed herein is a thin plate apparatus for removing solid debris from water containing such debris. The apparatus comprises a support frame consisting of two, parallel, spaced-apart vertical supports. The vertical supports are rigidly affixed to each other by rigid cross members. 
     The vertical supports each have a near end and a distal end, the distal end of each vertical support having a lateral support arm attached to it. 
     Each said lateral support arm has a downwardly depending set of posts, said posts being parallel to each other, said posts having attached thereto, a mounting plate, said mounting plate having an inside surface. 
     Each mounting plate has a centered opening in it, the center openings having one end of a common rotating shaft inserted in it. 
     There is mounted near the inside surface of each mounting plate, a square-tracked pulley and mounted on each such pulley, a drive chain comprised of rigid link bars being joined to each other such that each link bar pivotally interacts with adjacent link bars to form two adjacent drive chains that are attached to each other in a spaced-apart configuration by a plurality of rigid skimming bars. Each rigid skimming bar has a distal edge and mounted on each distal edge there is a soft, resilient skimming material, such as, for example, ultra high molecular weight polyethylene. 
     There is mounted near the distal end and between the vertical supports, a perforated plate, the perforated plate has a back and a multiplicity of such perforations therein in which the size of the perforations is calculated based on the formula: 
                 thickness   ⁢           ⁢   of   ⁢           ⁢   the   ⁢           ⁢   plate       hole   ⁢           ⁢   size       =     0.5   ⁢           ⁢   or   ⁢           ⁢   less           
wherein the thickness of the perforated plate does not exceed ¼ of an inch.
 
     There is a moveable solid effector plate mounted near the back of the perforated plate, said solid plate having a top end, and a front surface, a back surface, the front surface of the moveable solid effector plate is not touching the perforated plate, said moveable solid effector plate being movable up and down in essentially a vertical motion. 
     The movement of the moveable solid effector plate is provided by a lift and release mechanism, said lift and release mechanism comprising a lower pivotable support arm having near end and a distal end, the near end being pivotably mounted to the support frame, the distal end being pivotally mounted to a dampener means, said dampener means having a distal end, the dampener means being pivotally attached to the back surface of the moveable solid effector plate. 
     The top end of the moveable solid effector plate is pivotally coupled to a wiper blade, the wiper blade having a distal end. The distal end of the wiper blade is long enough to contact the top surface of a skimmer bar. A near arm of the wiper blade is coupled to an actuator cam, wherein the actuator cam can cause the wiper blade to scrape the top surface of the skimmer bar and cause the wiper blade to fall off the skimmer bar and allow the effector plate to drop by weight of gravity to its initial position at the base of the apparatus. 
     The wiper bar has rigidly mounted on it a linkage that is attached to an active component of the dampener means. 
     There is a drive means driveably connected to the common rotating shaft. 
     In another embodiment, there is a thin plate apparatus that corresponds to that set forth Supra, in which the apparatus comprises a rigid skimming bar having a corrugated distal edge and mounted on each corrugated distal edge, a soft, resilient skimming material. In this embodiment, there is mounted near the distal end and between the vertical supports, a corrugated perforated plate, said corrugated perforated plate having distal horizontal edges and a vertical distal edge and being configured to accept said rigid skimming bars. 
     In yet another embodiment, there is an apparatus having a corrugated perforated plate having, in addition, coarse screen components comprising solid vertical bars, wherein the solid vertical bars are located at the leading edges of the corrugations of the corrugated perforated plate and act as coarse screens for the apparatus. 
     In still another embodiment, there is an apparatus wherein there are valley plates built into the vertical edges of the corrugation of the perforated plate such that the valley plates are contacted by the distal vertical edge of the skimming bars such that the valley plate contacts provide stability to the skimmer bars. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the major components of an apparatus of this invention without the housing in place. 
         FIG. 2  is a side view of  FIG. 1  with most of the vertical support removed and showing some partial components for clarity. 
         FIG. 3  is a full side view of the placement of the perforated plate and the solid effector plate showing rolls or pills of solids on the front surface of the perforated plate. 
         FIG. 4  is a diagram of the flow of water through the perforated plate. 
         FIG. 5  is a full front view of a perforated flat plate of this invention. 
         FIG. 6A  is a section of the apparatus showing the corrugated configuration of the apparatus. 
         FIG. 6B  is a cross sectional view of the apparatus of  FIG. 6A  in which the relationship of the components is shown. 
         FIG. 6C  is an enlargement of the area C shown in  FIG. 6B . 
         FIG. 7A  is a top view of a portion of the corrugated fine screen/coarse screen of this invention. 
         FIG. 7B  is a top view of a portion of the flat fine screen/coarse screen of this invention. 
         FIG. 8  is the intimate detail of the linkage associated with the wiper blade actuation 
         FIG. 9  is a section of a perforated plate showing the water supply against the perforated plate. 
         FIG. 10A  is a view in perspective of a portion of an effector plate of this invention. 
         FIG. 10B  is a cross section of the device of  FIG. 10A  through line B-B of  FIG. 10A  and shows the detail of the cavity and openings of a water supply system. 
         FIG. 10C  is a section of a section of  FIG. 10B  showing the detail of the nozzle configuration. 
         FIG. 11  is another configuration of water supply to the back surface of a perforated plate. 
         FIG. 12  is shows the dirty water flow hydropression effect. 
         FIG. 13  is a full front view in perspective of a device of this invention with the housing intact. 
         FIG. 14  is a full rear view in perspective of the device of  FIG. 13  with the housing intact. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of this invention, the term “hydropression effect” is used to denote the basis on which the invention is superior to prior art devices. Hydropression is the term coined by the inventors herein to describe the effect of the thin flat plate fluid dynamics, as applied to this invention and this method, i.e. perforated plate/ultra screening of solids from water. The hydropression effect is essentially a fluid mechanics transport effect. To create this effect, a thin flat plate is placed perpendicularly into a flowing fluid, and in this case, water. Positive pressure is created on the front of the plate and negative pressure is created on the back of the plate. An effector plate (described infra) on the back (negative pressure side of the plate) of the screen and a skimmer on the front side of the screen (positive), move in unison to create a pressure differential. This differential creates a deflected water flow that pushes debris up the screen and makes it available for collection by a skimmer or similar apparatus. The debris is then discharged and removed from the water channel.  FIG. 4  shows this effect at  14 . This hydropression effect is also shown in  FIG. 12  wherein there is shown the dirty water flow by a large solid arrow designated as DW. There is shown a perforated plate  20 , an effector plate  21  and a skimmer bar  22 . The effector plate  21  and the skimmer bar  22  are synchronized in movement to optimize the cleaning of the perforated plate  20 . They move in the direction of the large open arrow designated as ES. 
     Turning to  FIG. 1 , there is shown an apparatus  1  of this invention with the housing removed, along with a support frame showing a vertical post  2 , a lateral top support arm  3 , a motor mounting panel  4 , a linked chain  5 , a rotating shaft  6  for the pulleys  7 , skimming bars  8 , perforated plate  9 , solid effector back plate  10 , dampener means  11  and hook  12  on the top of the linkage  19 . The linked chain  5  is very critical to the operation of this device. Such a chain can be found in U.S. Pat. No. 5,425,875, issued Jun. 20, 1995 for what it teaches about such chains. Said U.S. patent is incorporated herein by reference for what it teaches about such chains, their function, and advantages. 
     Also shown in  FIG. 1  are a wiper blade  16 , dead plate  17 , and the actuator cam  18 , all of which will be described infra. 
       FIG. 2 , wherein like numbers means like components as in  FIG. 1 , there is shown in addition, rolled or pilled particles  13 , along with the linkage hook up of the dampener means  11  and the mechanism that controls the ascent and descent of the solid plate  10 . 
       FIG. 3  is an illustration of the relationship of the flat perforated plate  9  and the solid plate  10  and in this Figure, there is also shown pilled or rolled solids material  13 . 
       FIG. 4  is an illustration of the flow of water through the perforated plate  9  and around the solid plate  10  causing a hydropression (backwash)  14  in front of the perforated plated  9 . 
       FIG. 5  is a full front view of the perforated plate  9  showing the multiplicity of small openings  15  therethrough. 
     The size of the openings for the perforated plates of this invention is calculated by the formula 
                 thickness   ⁢           ⁢   of   ⁢           ⁢   the   ⁢           ⁢   plate       hole   ⁢           ⁢   size       =     0.5   ⁢           ⁢   or   ⁢           ⁢   less           
wherein the thickness of the perforated plate does not exceed ¼ of an inch.
 
     In operation, and for illustration purposes, the flow of wastewater is from left to right in  FIG. 4 . Water passes through the perforated plate  9  where the solid plate  10  is not backing the perforated plate  9 . In those areas where the solid plate  10  is backing the perforated plate  9 , there is a backwash  14  which gently pushes the solid material  13  out of the openings  15  and back towards the flow of waste water. During this time, the skimming bars  8  are coordinated such that they follow the solid plate  10  and when a skimming bar  8  reaches the hook  12 , the linkage  19  is released which in turn releases the solid plate  9  to drop back to the bottom and start its ascent over with the next skimming bar  8  that is in line. 
     The skimming bar  8  does not scrape the front of the perforated plate  9 , but instead skims just short of the surface of the perforated plate  9  to remove the solids. 
     It has been discovered that the backwash  14  actually rolls the solid materials into a ball, which balls are separated from the openings  15  by the backwash  14  and float towards the upper surface of the waste water and then are moved along by the skimming bar  8  until the solids reach the top where they are moved off into a recovery device and disposed of. 
     Turning now to a second embodiment of this invention, there is shown in  FIG. 6A  a portion of a corrugated system, that is, a corrugated perforated plate  20 , corrugated effector plate  21 , whose configuration matches that of the corrugated perforated plate  20 , and a corrugated skimmer bar  22 . 
     The purpose of the corrugation is at least three-fold, that is, the corrugation provides more surface area than does a flat plate; the corrugation creates more rigidity and therefore, stability of the plate, and it provides a basis for placing additional components into the apparatus to arrive at more benefits, all of which will be explained infra. 
       FIG. 6B  is a section of the apparatus of  FIG. 6A  in which there is shown the skimmer  22 , the effector plate  21  and the perforated plate  20 , and this also show their relationship. Note from  FIGS. 6B and 6C  that the skimmer  22  does not touch the surface of the perforated plate and therefore, this is not a scraper mechanism. The effector plate  21  sets up against the back of the corrugated perforated plate  20 . As can be noted in  FIG. 10B , the configuration of the corrugated skimmer bars  22  entail a height, on average of 1.5 inches and this value can range from at least ½ inch and can be as high as 3 inches. This as opposed to a thin plate which would generally not have the required rigidity to provide the benefits cited herein. 
     Turning now to another embodiment of this invention which is a coarse screen in combination with a fine screen used as the perforated plate, the perforated plate  23  is shown in  FIG. 7A . This plate  23  is shown as a corrugated plate, but can be manufactured as a flat plate  47  ( FIG. 7B ). 
     The perforated plate  23  is comprised of thin screen plate  24  and coarse screen bars  25 , in which the thin screen plates  24  are connected together at the downside  26  by welding or by using a fastener  27  (only one example shown). As can be observed from  FIG. 7A , one embodiment of the thin screen  23  forms a V-shape such that when they are put together, they create a corrugated screen. An additional embodiment of this screen is a flat screen  47  in combination with a flat solid effector plate  48 . The solid bars  49  are the coarse screen for this configuration. 
       FIG. 7B  is a top view and shows a version of the flat screen  47 , the solid bars  49 , and flat effector plate  48  in combination. 
     At the leading edge  28  of the thin screens  24  (perforated plate material), and positioned between the leading edges  28  of the thin screens  24 , are metal bars  29  which are vertically held between the leading edges  28  to form the coarse screen  25 . These bars  29  constitute a coarse screen  25 . There is also a component  30 , which is a metal bar that is used to maintain the correct distances between the fine screens  24  and to provide stability to device. The thin screen/coarse screen is not easily manufactured, and the use of the bars  30  help ease the manufacturing process. 
     The coarse screen  25  screens out cloth, paper, wood and other larger sized particles from the water flow before those materials encounter the thin screens  23  and therefore prevent early clogging of the thin screens  23 . 
     In use, these fine screen/coarse screens are substituted in the apparatus for the perforated plates set forth and described above. 
     Turning now to another embodiment of this invention, there is shown in  FIG. 6C  the use of valley plates  31 . The valley plates  31  are located in the tip end  32  of the perforated plates  20 . The skimmer  22  does not touch the perforated plate  20 , but rather, the skimmer  22  rides on the valley plates  31  and by this mechanism, there is created a gap between the perforated plate  20  and the skimmer  22 . This gap allows for debris to be rolled up the perforated plate  20 . The effector plate  21  is not touching the perforated plate and does not have contact with the backside of the perforated plate  20 . 
       FIG. 8  deals with the intimate detail of the linkage associated with the wiper blade actuation. The interface between the skimmer  20  and the wiper blade  16  actuates the effector plate  21  via a linkage  33 . The actuator cam  18  causes the wiper blade  16  to scrape clean the skimmer  22 . The actuator cam  18  also causes the wiper blade  16  to fall off the skimmer  22  which allows gravity to cycle the effector actuator back to its initial condition. The skimmers  22  and the effector plates  21  require synchronization. 
     With regard to the use of water in conjunction with the perforated plates of this invention, attention is directed to  FIG. 9  wherein there is shown a section of a perforated plate  20 . In addition, there is shown a series of water supply nozzles  34 . Not shown is the means by which the water is supplied to the nozzles  34 , however, there is shown a hose  42 . As noted, the nozzles  34  are intimately located behind the perforated plate  20  and supply pressurized water  35  to the back surface  36  of the perforated plate  20 . The purpose of this water supply is to pressure the solids that become stuck in the perforations of the perforated plate  20 . The water is synchronized to pressurize just as the skimmer bars  22  (not shown) are rising on the perforated plate  2  such that the solids are suspended in the flowing water at the front surface  37  of the perforated plate  20  such that the skimmer bars  22  (not shown in this Figure) can move the solids upwards along the front surface of the perforated plate  20 . By this means, the hydropression effect is enhanced. 
     Also contemplated within the scope of this invention is to provide corrugated water supply nozzles  38  that are located in the effector plate  21 , shown in  FIG. 10A , wherein the water  35  is supplied to the back surface  36  of the perforated plate  20 . As can be noted from  FIG. 10A , which is a view in perspective of a portion of an effector plate  21 , the nozzles  38  are in the form of openings  39  in a mid-line  43  of the front face  40  of the effector plate  21 . 
       FIG. 10B  is a cross section of the device of  FIG. 10A  through line B-B and shows the detail of the cavity  41  and openings  39 . Note in  FIG. 10C , an alternative opening configuration in opening  39 . 
     As noted Supra, in this configuration of nozzles operates in the same manner, by forcing water against the back surface of the perforated plate  20  to create an enhance hydropression effect. 
     In yet another embodiment of this invention, there is shown in  FIG. 11  another configuration of water supply  45  to the back surface  36  of a perforated plate  20 . This configuration depends on the velocity of the water, not water pressure. Note that the configuration shown in  FIG. 10A  shows the water supply  34  as being closely associated with the back surface  36  of the perforated plate  20  whereas in this configuration, the water supply  45  is not closely associated with the back surface  36 , but shows a gap  44  between the water supply  45  and the back surface  36  of the perforated plate  20 . This configuration can be used on flat perforated plates and on corrugated perforated plates. The type of the water supply  45  is not critical in this configuration as long as the water supply  45  can provide sufficient velocity to the water and thus, the designation  45  is for a generic water supply. 
       FIG. 13  is a full front view in perspective of a device of this invention with the housing  46  intact. 
       FIG. 14  is a full rear view in perspective of the device of  FIG. 13 . 
     The perforated plates of this invention can be manufactured from any water impermeable building material and that can be, for example, wood, plastic, webbed textile, mesh, netting, or metal, wherein for this invention, preferred is metal.