Abstract:
A method and apparatus for selectively removing fine sediments from a water body bottom using a dredging head with one or more intake openings situated to accelerate flows through the interior of the head and across the water body bottom causing fine particles to become suspended in a slurry outflowing from the head for disposal, while coarser, heavier, bottom gravels remain in place. The stream cleaner dredging head includes a main body having at least one intake, at least one plate attachment feature, a discharge point, and an at least partly open bottom; a flow-adjusting plate that is adjustably connected to the at least one plate attachment feature and configured to adjust a fluid flow through the main body from the at least one intake, and a hose attachment connected to the discharge point of the main body.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a non-provisional application based upon U.S. provisional patent application Ser. No. 61/909,159, entitled “STREAM CLEANER WITH SELECTIVE SEDIMENT DREDGING HEAD,” filed Nov. 26, 2013, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a water body cleaner, and, more particularly, to a water body cleaner with a sediment dredging head. 
         [0004]    2. Description of the Related Art 
         [0005]    Sedimentation of streams and lakes is listed by EPA as one of the most damaging pollutants of US waterways. Sedimentation chokes otherwise native coarse gravel bottoms such that the streams are no longer supportive of a diversity of native aquatic species, while also diminishing habitat for fisheries. The polluting fine sediments have entered our streams and lakes from a combination of unnatural sources, including poor agricultural practices causing wide spread soil erosion and run off, run off from streets and man-made surfaces, run off from disturbed construction sites, run off from increased deforestation, and run off from both urban and rural roads and highways. 
         [0006]    In the last few decades, much experimentation and efforts have been made to restore streams by removing the undesirable fine sediments and restoring a relatively clean coarse gravel and cobble stream bed. 
         [0007]    One such device is commercially sold by Streamside Systems, LLC as the Sand Wand™, which uses the unnatural method of a jetting system that drives water into the bottom and disrupts the structure to dislodge sediments into a slurry, which is then removed with a separate suctioning system. The Sand Wand is a dual system, which requires two separate heads, two sets of hose lines and two separate pumping systems. The Sand Wand&#39;s methodology is also disruptive to the stream bed, and relatively cumbersome to operate. 
         [0008]    Shear stress is the ability of liquid flows to entrain (suspend) sediments and transport that mixed flow of liquid and sediment (slurry). Sediment particles in the streambed become suspended into the flows when the resistance to shear is exceeded, or what is known as the critical shear stress. The greater the shear stress the greater the particle that can be transported. Shear stress in a natural stream is affected by many factors, including, change in elevation, configuration of the channel, volume of flows, and size of sediments within the stream bed. Where shear stress increases, the capacity to mobilize and transport sediment increases in both volume and particle size. Where shear stress decreases the capacity to mobilize and transport sediment decreases in both volume and particle size. 
         [0009]    Unfortunately, many US streams have been overwhelmed with fine sediment pollution to the point that those steams no longer have the capacity to create critical shear stress forces sufficient to mobilize and remove sediment pollution, leaving the stream habitats permanently degraded and without the necessary coarse gravel and cobble bottom conditions needed to support a healthy stream ecology. 
         [0010]    What is needed in the art is a simpler system for removing undesirable sediment from a stream or other water body with less disruption to the stream or water body&#39;s bottom conditions. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention provides a dredging head for selectively removing fine sediments from a stream, lake, or other water body&#39;s bottom that mimics the natural removal of sediments from a stream. 
         [0012]    The invention in one form is directed to a dredging head that includes a main body having at least one intake, at least one plate attachment feature, a discharge point, and an at least partly open bottom; a flow-adjusting plate that is adjustably connected to the at least one plate attachment feature and configured to adjust a fluid flow through the main body from the at least one intake, and a hose attachment connected to the discharge point of the main body. The flow-adjusting plate can be readily adjusted to change the flow characteristics of fluid that enters an intake by changing the geometry of the intake or incorporating a baffle with the flow-adjusting plate that can alter the fluid flow. The one or more plate attachment features can allow for attachment of the flow-adjusting plate to the main body and can be configured to change the coverage of the intake by the flow-adjusting plate. The hose attachment connects to the discharge point of the main body and allows for outflow of a sediment slurry that is produced during the dredging head&#39;s operation. In one possible embodiment, the geometry of the main body can be altered to form a sloped front surface where the one or more intakes are located. The dredging head is configured so that the flow of fluid through the one or more intakes, through the main body, and out the discharge point can be powered by a standard trash pump. The dredging head can be configured to operate at either a hand held or construction equipment size. When the dredging head is configured to be hand held, a handle can be installed on the main body. 
         [0013]    An advantage of the present invention is the ability to mimic a flowing river&#39;s natural ability to suspend and mobilize sediments during increased flow velocities. The higher the velocity of the flow through the dredging head, the greater its ability to suspend materials within those flows. By mimicking the natural phenomenon of critical shear stress, the present invention is able to remove undesirable sediments from a water body while leaving desirable coarse gravel and cobble in place and not disturbing the bottom structure. 
         [0014]    Another advantage is the present invention requires only one pumping system, uses an open head and doesn&#39;t require a separate jet. 
         [0015]    Yet another advantage of the present invention is that it can be used to clean up bottom oil spill contamination from water bodies without significant disturbance to the native bottom. 
         [0016]    Yet another advantage of the present invention is that it can be used to clean contaminated sediment without significant release of contaminants during the cleaning process. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0018]      FIG. 1  is a perspective view of an embodiment of a main body of a dredging head according to the present invention; 
           [0019]      FIG. 2  is a perspective view of an embodiment of a flow-adjusting plate according to the present invention; 
           [0020]      FIG. 3  is a perspective view of another embodiment of a flow-adjusting plate according to the present invention; 
           [0021]      FIG. 4  is a perspective view of an embodiment of a dredging head according to the present invention that includes the main body shown in  FIG. 1  with portions removed to show fine sediments being removed from a water body bottom; 
           [0022]      FIG. 5  is a perspective view of another embodiment of a main body of a dredging head according to the present invention; 
           [0023]      FIG. 6  is a perspective view of another embodiment of a dredging head according to the present invention that includes the main body shown in  FIG. 5 ; 
           [0024]      FIG. 7  is a top view of the dredging head shown in  FIG. 6 ; and 
           [0025]      FIG. 8  is a cross-sectional view of the dredging head shown in  FIG. 7  taken along line  8 - 8 . 
       
    
    
       [0026]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown an embodiment of a dredging head  10  according to the present invention which generally includes a main body  12  having an open bottom  13  geometric shape with multiple intake openings  14 ,  16  in a front surface  18  of the main body  12 . The intake openings  14 ,  16  can be slits situated in the horizontal plane of the dredging head  10 . The intakes  14 ,  16  situated in the front surface  18  of the main body  12  accelerate flows through the head  10  and across the open bottom  13  where undesirable fine sediments from a water body bottom will be suspended into a slurry for outflow, while coarser gravel and cobble remain in place. As used herein, a “water body bottom” can refer to the bottom of a natural water body, such as a stream or lake bed, or to the bottom of a man-made water body, such as the bottom of a swimming pool. As shown, the bottom  13  is almost completely open, but the percentage of the bottom  13  that is open can be varied, as desired, to alter the sediment suspension or entrainment and removal that the dredging head  10  can perform. 
         [0028]    The dredging head  10  is shaped with a low profile at the front associated with the intake location, which focuses the highest velocity flows in the front of the dredging head  10  across the water body bottom to entrain or suspend fine sediments within head flows. The height of the head main body  12  can increase in size from the front surface  18  to a rear surface  20  opposite the front surface  18 , giving the main body  12  a sloped front surface  18 , and can reduce flow velocities where a discharge point  22  of the main body  12  is located. This shaped profile of the dredging head  10  maximizes flow velocities and shear stress forces to the front for the purposes of initiating the entraining or suspension of fine sediments into a slurry, while slowing flow velocities and decreasing shear stress through the dredging head  10  rearward to the discharge point  22 , which can allow desirable coarse gravel that is inadvertently dislodged to settle back to the water body bottom, while maintaining rearward velocities and shear stress forces sufficient to discharge the suspended slurry of undesirable fine sediments from the dredging head  10 . 
         [0029]    The discharge point  22  from the dredging head  10  is connected to an attachment  24  for a hose (not shown) that is in turn attached to a pump (not shown). The pump pulls flows into the head  10  through the intakes  14 ,  16  and pulls the slurry of sediments through the dredging head  10  into the discharge point  22 . The slurry can then continue through the discharge hose, through the pump, and out of the pump to a disposal location, such as a settling pit or filtration bags. 
         [0030]    As shown in  FIG. 4 , multiple intakes  14 ,  16  in the front surface  18  of the main body  12  allow for adjustment of the direction and volume of flows through the dredging head  10 , and the flows through any individual intake  14  or  16  can be increased or decreased by use of flow-adjusting plates  26 ,  28  positioned in a full open position, relative to the intakes  14  or  16 , various partially open positions and a full closed position. The flow-adjusting plates  26 ,  28  are adjustably connected to plate attachment features  30 , shown in  FIGS. 1 and 4  as openings formed in side surfaces  32  of the main body  12 . The direction of flows through individual intakes  14 ,  16  can be adjusted through the use of flow-adjusting plate  28 , shown in  FIG. 2 , that simply covers a portion of its respective intake, or by flow-adjusting plate  26 , shown in  FIG. 3 , which includes an attached baffle  36  that will further direct the flow of fluid through the dredging head  10  after the fluid has entered the main body  12 . Flows through the intakes  14 ,  16  can also be increased or decreased by adjusting the capacity of the pump. 
         [0031]    The number of intakes open, the setting of those openings, the use of baffles, and the setting of the pump capacity all will vary dependent upon the conditions of the water body bottom. Relevant conditions include the size of undesirable sediment to be removed, size of the desired coarser materials intended to remain at the water body bottom, and the ratio of undesirable to desirable materials at any given location in the water body bottom. 
         [0032]    Full opening of both intakes  14 ,  16 , without the use of flow-adjusting plates  26  with baffles  36 , will decrease flow velocity through the head  10  and diffuse flows across the water body bottom, thus diminishing the dredging head&#39;s  10  capacity to suspend and remove anything but the finest organic particulate from the water body bottom. 
         [0033]    Opening only the lowest intake  14 , while closing the upper intake  16 , will conversely accelerate the velocity of flows entering the dredging head  10  and focus the flow along the bottom  13 , thus increasing the dredging head&#39;s  10  capacity for suspending and removing sediments, both in size and volume. 
         [0034]    Closing the bottom intake structure  14 , while opening the upper intake  16 , will achieve the same velocity of flows entering the dredging head  10 , assuming intakes  14  and  16  are equally sized, but at a location that will diffuse the force of flows across the bottom  13 , thus diminishing both the particle size and volume of sediments the dredging head  10  is capable of removing. 
         [0035]    Adding a baffle to the flow-adjusting plates allows for directing the accelerated flows through the dredging head  10  at the closest possible distance to the bottom  13 , thus increasing the focus of accelerated flows across the bottom  13 , which in turn increases the size and volume of sediments the dredging head  10  is capable of removing. 
         [0036]    As can be seen, the flow-adjusting plates  26 ,  28  can be adjustably connected to the plate attachment features  30  so that the free flow area of one or more of the intakes  14 ,  16  can be changed. As used herein, “free flow area” refers to the portion of the intakes  14 ,  16  that are uncovered and will allow fluid flow to enter the main body  12  of the dredging head  10  through the intakes  14 ,  16 . The flow-adjusting plates  26 ,  28  can be formed of any material and have any suitable thickness that allows for them to direct water flow into the main body  12  and produce sufficient shear stress across the water body bottom to dislodge sediments that have accumulated. The plate attachment features  30 , while shown as openings, could be other types of features that allow for the flow-adjusting plates  26 ,  28  to be adjustably connected to the plate attachment features  30  and adjust the flow characteristics and direction of fluid through the main body  12  through one or more of the intakes  14  and  16 . 
         [0037]    As shown, the main body  12  can include, in addition to the front surface  18 , rear surface  20  and side surfaces  32 , a top surface  38  that is opposed to the bottom  13  to form a roughly rectangular box with a sloped front surface  18 . The bottom  13  can have a greater geometric area than the top surface  38  so that the main body  12  can rest more stably on the bottom  13  than the top surface  38 . As shown, the side surfaces  32  and rear surface  20  can all be generally orthogonal relative to the bottom  13  and top surface  38 , with the front surface  18  extending from the bottom  13 , which is longer than the top surface  38 , toward the top surface  38 . The surfaces of the main body  12  can also form acute angles relative to one another, if desired. A bottom perimeter  42  is defined by the bottom edges of the surfaces  18 ,  32 , and  40  with a flange  44  extending away from the bottom perimeter  42 . The flange  44  can be substantially flat or can be angled, as desired, to make it easier for the dredging head  10  to sit on a stream bed, or other water body bottom. The flange  44  can also have weights placed thereon, such as rocks of the water body, or be otherwise embedded into the water body bottom to secure the dredging head  10  to the water body bottom. The discharge point  22  is shown as being located on top surface  38 , but could be placed on any of the other surfaces  18 ,  32  and  40 , if desired, depending on the flow characteristics of fluid and sediment through the main body  12 . It should be appreciated that references to the “front,” “rear,” “side,” “top,” and “bottom” of the main body  12  are for convenience of description for the dredging head&#39;s  10  various features&#39; and surfaces&#39; positioning relative to one another and are not intended to limit the configurations of the dredging head  10  according to the present invention. 
         [0038]    Referring now to  FIGS. 5-8 , another embodiment of a dredging head  50  according to the present invention is shown that includes a main body  52  with intakes  54  and  56 , plate attachment features  58  and  60 , and a discharge point  62 , a flow-adjusting plate  64  adjustably connected to the plate attachment features  58  and  60 , and a hose attachment  63  that is connected to the discharge point  62  of the main body  52 . As can be seen, the main body  52  has a similar shape to the main body  12  shown in  FIGS. 1-4 , with a front surface  66 , an open bottom  68 , a pair of side surfaces  70 , a rear surface  72  opposed to the front surface  66 , and a top surface  74  opposed to the bottom  68 . The front surface  66  is sloped in a direction away from the bottom  68  toward the top surface  74 . The front surface  66  can connect to a cutter plate  76  that is sloped oppositely to the front surface  66 , i.e., toward the bottom  68 . As shown in  FIG. 8 , the cutter plate  76  can extend from the front surface  66  to the bottom  68 , to create a roughly 90 degree angle with the front surface  66 . A bottom perimeter  78  can be defined at the bottoms of the side surfaces  70 , rear surface  72 , and cutter plate  76  around the main body  52 , with a flange  80  extending away from the bottom perimeter  78 . The flange  80  can have one or more anchoring openings  82  that can have anchoring pins (not shown) pushed through to help anchor the dredging head  50  within a water body bottom. An additional intake  84  can be formed between the cutter plate  76  and the flange  80 , which will allow more fluid to flow through the water body bottom to loosen sediment from the water body bottom that can then be forced out of the discharge point  62 . 
         [0039]    As can be seen, the plate attachment features  58 , most clearly shown in  FIG. 5 , are arced slots that are formed in the side surfaces  70  of the main body  52  and the plate attachment features  60  are blade supports with openings that define an axis of rotation Al therebetween for the flow-adjusting plate  64  when it is secured to the blade supports  60 . Pins  86 , shown in  FIGS. 6 and 8 , on the flow-adjusting plate  64  can be placed in the arced slots  58  so that the angle formed between the flow-adjusting plate  64  and the front surface  66  can be adjusted by sliding the pins  86  through the arced slots  58  and rotating a plate handle  88  of the flow-adjusting plate  64  about the axis of rotation A 1 . Once the flow-adjusting plate  64  creates a desired angle with the front surface  66 , the pins  86  can be anchored in position to prevent the flow-adjusting plate  64  from easily being moved into a different orientation during operation. One way of anchoring the pins  86  in position to resist movement of the flow-adjusting plate  64  is to tighten the pins  86  to the side surfaces  70  using a fastener (not shown), such as a nut. It should be appreciated that the pins  86  can be anchored in any reversible manner that allows the angle formed between the flow-adjusting plate  64  and front surface  66  to be adjustable. It should be further appreciated that the arced slots  58  and blade supports  60  could be replaced with different plate attachment features, such as the openings  30  shown in  FIGS. 1 and 4 , that allow for the flow-adjusting plate  64  to be adjustably connected. By adjustably connecting the flow-adjusting plate  64  to the attachment features  58  and  60 , the angle formed between the flow-adjusting plate  64  and front surface  66  can be adjusted, as desired, to achieve various fluid flow velocities through the intake  54  and across the bottom  68  of the dredging head  50 . For example, the pins  86  can be anchored to an end of the arced slots  58  closest to the front surface  66  to create a small angle between the flow-adjusting plate  64  and front surface  66  that can create a high flow velocity of fluid through the intake  54  to travel toward the bottom  68  of the dredging head  50 . Similarly, anchoring the pins  86  to an end of the arced slots  58  closest to the rear surface  72  creates a large angle between the flow-adjusting plate  64  and front surface  66  that can create a low velocity of fluid through the intake  54  to travel toward the bottom  68  of the dredging head  50 . The pins  86  can also be anchored between the ends of the arced slots  58  to form various angles between the flow-adjusting plate  64  and front surface  66  that give other flow velocities of fluid through the intake  54 . The flow-adjusting plate  64  can therefore re-direct flow into the main body  52  in various ways to create the critical shear stress necessary to remove fine sediments from the bottom of a water body covered by the dredging head  50 . If desired, a baffle  65  can be attached to the flow-adjusting plate  64 , as shown, similar to flow-adjusting plate  26  with baffle  36  previously described and shown in  FIGS. 3 and 4 . As can be seen, the baffle  65  can be attached to the flow-adjusting plate  64  to further direct the flow of fluid through the intake  54  and across the bottom  68  of the dredging head  50 , which will sweep across the water body bottom to entrap fine sediment from the water body bottom to be removed through the discharge point  62 . As shown, the baffle  65  can be attached to the flow-adjusting plate  64  so that the baffle  65  will extend along a plane that is generally parallel to the bottom  68  of the dredging head  50 , but other relative orientations between the flow-adjusting plate  64  and baffle  65  can also be chosen as desired. 
         [0040]    Referring now to  FIGS. 6-8 , it can be seen that intake  56  can be covered with a removable filter  90  that has a filter plate  92 , a filter handle  94  connected to the filter plate  92 , and a filter screen  96 . The filter plate  92  can entirely cover the intake  56 , as shown, or can cover only a portion of the intake  56  to allow fluid to flow into the main body  52  through the intake  56 . The filter plate  92  can be secured to the main body  52 , if desired, to make removal of the filter  90  more difficult or make the filter  90  non-removable. As shown in  FIG. 8 , the filter screen  96  can be held in a pair of filter slides  98  that are connected to the main body  52 . The filter slides  98  allow for easy orientation of the filter screen  96  within the main body  52  and also provide some support for the filter screen  96  during operation. If filter slides  98  are included, the filter  90  can be removed from and placed into the dredging head  50  by sliding the filter screen  96  along the filter slides  98  using the filter handle  94 . The filter slides  98  can be attached to the main body  52  so that they do not extend entirely to the rear surface  72 , to lessen the risk that gravel and debris loosened by the dredging head  50  block the filter slides  98  and make sliding of the filter screen  96  across the filter slides  98  difficult. The filter screen  96  can have apertures (not shown) that are sized to allow a certain size of fine sediment to pass through the filter screen  96  from the bottom  68  of the dredging head  50  toward the discharge point  62  on the top surface  74 , while preventing coarse gravel and cobble from passing through the filter screen  96  and being undesirably removed from the water body bottom. The filter screen  96  can therefore allow for high flow velocities to be created in the dredging head  50  without removing the desirable coarse gravel and cobble from the water body bottom, which can increase the fine sediment removal amount and rate. 
         [0041]    The flange  80  of the dredging head  50  can have a flexible material  100 , shown as a rubber gasket, surrounding the flange  80 . The rubber gasket  100  can surround the entirety of the flange  80 , as shown, or could surround only a portion of the flange  80  if desired. The rubber gasket  100  can surround the flange  80  in a variety of ways, such as by connection to the flange  80  or having a compartment formed in the rubber gasket  100  that the flange  80  slides into and rests within. The rubber gasket  100  can be included to account for the variety and heterogeneity of water body bottoms that the dredging head  50  encounters when removing sediment. A water body bottom tends to be an uneven surface, due to the presence of differently sized and shaped objects like rocks, plant matter, debris, etc., that makes creating a seal between the dredging head  50  and water body bottom difficult. Without a seal formed between the dredging head  50  and the water body bottom, the fluid flow that is directed into the dredging head  50  tends not to entrap or entrain fine sediment as efficiently as when a seal is created between the dredging head  50  and the water body bottom, due to pressure leakage out of the main body  52 . The rubber gasket  100  can be pulled toward the water body bottom due to suction that is created within the dredging head  50  by a pump (not shown) connected to the hose attachment  63 , creating a seal around objects on the water body bottom that make the water body bottom an uneven surface. In this respect, the rubber gasket  100  can help create a seal between the dredging head  50  and water body bottom to increase the efficiency of fine sediment removal by the dredging head  50 . 
         [0042]    The dredging head  50  can further include a handle  102  connected to the main body  52  that includes a handling portion  104  and a connector  106  that connects the handle  102  to the main body  52 . As shown, the handle  102  is connected to the top surface  74  of the main body  52  by the connector  106 , but the handle  102  could be connected to any surface of the main body  52 . The handle  102  can allow for the dredging head  50  to be pulled or pushed across a water body bottom or other surface. The handling portion  104  can be adjustably connected to the connector  106  such that the angle that the handling portion  104  forms relative to the surface of the main body  52  that the connector  106  is attached to can be adjusted. The length of the handling portion  104  can also be adjusted to account for various ways that the dredging head  50  is to be pulled or pushed across the water body bottom. As shown, the handling portion  104  is adapted to be pulled by a living creature, such as a human, but could also be adapted to be pulled by a water vessel, such as a boat, or other moving object that can provide a force to push or pull the dredging head  50  along the water body bottom. 
         [0043]    While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.