Abstract:
An apparatus and method for skimming an upper liquid layer from a fluid body. A pond surface decanter and skimmer uses a floating platform and suspended plenum to draw an upper layer of liquid off of a lower liquid without removing the lower liquid. The skimmer may be used to separate a heavy and light liquid. The skimmer is useful in many applications such as removing rainwater from evaporation ponds.

Description:
PRIORITY CLAIM  
       [0001]    The present application claims priority to U.S. Provisional Patent Application Ser. No. 61/543,949, filed Oct. 6, 2011, which is expressly incorporated herein in its entirety. 
     
    
     THE FIELD OF THE INVENTION  
       [0002]    The present invention relates to devices and methods for skimming. More specifically, the present invention relates to a surface decanter and skimmer that can skim a layer of liquid off the surface of a body of liquid. 
       BACKGROUND  
       [0003]    In many situations, it is necessary to skim a liquid surface layer off of a body of water or other liquid. For example, solar ponds may be used to evaporate water from a mineral solution to thereby concentrate the minerals. Rain water, however, forms a fresh water layer on top of the mineral brine. Without an alternate method of removing the rainwater, this fresh water layer must be evaporated off the pond, delaying mineral production and extraction of the concentrated minerals. Thus, it is preferable to remove this layer of fresh water. 
         [0004]    Another example where it is desirable to skim a surface layer from a body of water is in the case of oil or chemical spills. Many oil or chemical spills will float on top of a body of water. In this type of situation and other similar situations, it is desirable to remove an unwanted liquid surface layer from a liquid body. 
         [0005]    Furthermore, it is often desirable, when removing a top layer off a body of liquid, to leave the lower layer of the liquid surface relatively undisturbed. Depending on the circumstances, the depth of upper liquid to be removed will vary, and thus the amount of upper liquid that can be removed before the lower layer of liquid is disturbed will vary. For example, a very shallow upper liquid surface layer may be present, or the liquid surface layer could be deeper. 
         [0006]    Thus there is a need for a device and method which allow a surface layer to be skimmed off a body of water or other liquid. It is further desired that such a device and method be able to remove the upper liquid layer without disturbing or removing a significant portion of the lower layer of liquid. It is also further desired that the device and method be adjustable so as to provide for removal of surface layers of various depths. It is also desired that the device be relatively simple in construction and the method relatively simple to employ. 
       SUMMARY OF THE INVENTION  
       [0007]    The present invention provides a device comprising a float platform, a pump connected to the float platform with an inlet for drawing liquid from below the float platform, and a sump suspended from the bottom of the float platform. The sump has a bottom and sides extending upwardly from the bottom, and the sump is larger in dimension than the float platform to form a gap between the sides of the sump and the float platform. 
         [0008]    When placed in liquid, the float platform of the skimming device is configured to be partially submerged and the sump is configured to be completely submerged. 
         [0009]    The skimmer is adapted to allow liquid to be drawn above the sump sides, between the sump and the float platform, and through the pump. 
         [0010]    The pump of the skimmer also comprises an outlet. 
         [0011]    The sump of the skimmer is suspended from the float platform by at least one adjustable attachment member. The attachment member may be adjustable to vary the distance between the float platform and the sump. 
         [0012]    A pond surface skimmer may comprise a planar float platform with a top side and a bottom side, a pump connected configured to withdraw liquid from below the float platform, and a plenum, or sump, with a bottom and sides extending upwardly therefrom, suspended from the float platform. 
         [0013]    The plenum, or sump, of the pond surface skimmer may have larger dimensions than the float platform so as to form a gap between the sides of the plenum and the float platform. 
         [0014]    The plenum may be suspended from the float platform adjustably, such that the distance between the float platform and the bottom of the plenum may be adjusted. 
         [0015]    According to another aspect, a skimming device may comprise a float platform with a collecting container connected to the float platform. The collecting container is at least partially beneath the float platform, the collecting container having a bottom surface and sidewalls extending upwardly from the bottom surface. The collecting container has an open top, defining a sump within which the float platform at least partially sits. 
         [0016]    The sidewalls of the collecting container form a top edge over which liquid may flow into the sump. The float platform and the collecting container are adjustably connected such that the top edge over which liquid may flow is adjustable relative to the float platform. 
         [0017]    The skimming device may comprise a pump connected to the float platform, the pump having an inlet extending from the pump to below the float platform to pump liquid from the sump. 
         [0018]    According to another aspect, an apparatus for skimming off a top layer of a body of liquid may comprise a floating element, a sump for collecting a top layer of a body of liquid, and a pump for discharging the top layer of the body of liquid. The sump is adjustably connected to the floating element and is comprised of a bottom portion with sidewalls extending upwardly from the bottom. The sump has an open top, and the top layer of the body of liquid may flow into the open top of the sump. 
         [0019]    The sump and floating element may be adjustably connected, for example, by at least one threaded rod and nut. The pump may be disposed on the floating element, with an inlet that terminates below the floating element to discharge liquid from the container. Alternatively, the pump may be placed at a location remote from the floating element, and the pump comprises an inlet extending to below the floating element. 
         [0020]    According to another aspect, a method is provided to skim a top layer of a body of liquid. The method comprises providing a skimming device as generally described herein, placing the skimming device on a surface of the body of liquid, the liquid having a top layer and a bottom layer, such that the float platform is located on a surface of the body of liquid and the collecting container (i.e., the sump, plenum, etc.) is submerged in the liquid. Then, the distance between the float platform and the collecting container is adjusted via the adjustable attachment members such that the top of the collecting container sidewalls is below the upper surface of the top layer and above the upper surface of the bottom layer. Finally, the pump is activated to evacuate the liquid from below the float platform. 
         [0021]    The method may also comprise the top layer of the body of liquid flowing below the float platform, over the top of the collecting container sidewalls, and being evacuated from below the float platform via the pump. Furthermore, the method may comprise evacuating the liquid from below the float platform at more than one pumping speed. 
         [0022]    These and other aspects of the present invention are realized in a pond surface decanter and skimmer and method of use as shown and described in the following figures and related description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0023]    Various configurations of the present invention are shown and described in reference to the numbered drawings wherein: 
           [0024]      FIG. 1  shows a perspective view of the skimming apparatus of the present invention; 
           [0025]      FIG. 2  shows a top view of the skimmer of  FIG. 1 ; 
           [0026]      FIG. 3A  shows a diagram illustrating a section view of the skimmer of  FIG. 2 , taken along the dashed line III with a relatively shallow skim depth illustrated; 
           [0027]      FIG. 3B  shows a diagram illustrating a section view of the skimmer of  FIG. 2 , taken along the dashed line III with a deeper skim depth illustrated; and 
           [0028]      FIG. 4  shows a side, partial cross-sectional view of the pond skimmer of  FIG. 1  located in a body of liquid. 
       
    
    
       [0029]    It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The configurations shown accomplish various aspects and objects of the invention. It is appreciated that it is not possible to clearly show each element and aspect of the invention in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the invention in greater clarity. Similarly, not every embodiment or configuration need accomplish all advantages of the present invention. 
       DETAILED DESCRIPTION  
       [0030]    The invention and accompanying drawings will now be discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The drawings and descriptions are exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims. 
         [0031]    Turning now to  FIG. 1 , a perspective view of a pond skimmer of the present invention. The skimmer, generally indicated at  10 , includes an upper portion, float platform  14 , and a lower portion, plenum  30 . The plenum  30  forms a collecting space for liquids, or a sump. The float platform  14  may be generally planer and includes an upper surface  14   a  (visible from the perspective of  FIG. 1 ) and a lower surface  14   b.  A pump  18  is connected to the upper surface of the float platform  14   a.  The pump may be physically attached to the float platform, for example, bolted to the platform, or the pump may be at a location remote from the platform and be connected via the pump inlet  22 . 
         [0032]    The pump  18  may be driven electrically or by a combustion engine as desired. The pump may be any device capable of withdrawing fluid. The pump may be any type desired for the purpose, and those with skill in the art will recognize that many types of pumps may be used. By way of example and not of limitation, a vertical turbine pump or a centrifugal horizontal or vertical split case pump, etc. may be used. 
         [0033]    The pump  18  may be connected to an inlet passage  22  which passes down through the top of the float platform  14  and terminates adjacent the bottom of the float platform  14  to draw liquid from below the float platform  14 . The inlet need not extend through the float platform, but may come around the side of the float platform  14  and terminate below the float platform  14 . Additionally, if the pump  18  is located at a place remote from the float platform (such as on land, or on another floating structure, etc.) the inlet  22  need only terminate within the plenum  30  or sump. The pump  18  may also be connected to an outlet passage  26  which connects to a hose (not shown) or other device in order to discharge liquid into any desired receptacle. 
         [0034]    The plenum or sump  30  is attached to the float platform  14  and is suspended beneath the float platform by attachment members  34 . The plenum  30  has a bottom  30   a  and sidewalls  30   b  which are closed so that the interior of the plenum, or the plenum space  42  (above the plenum bottom  30   a  and between the sidewalls of the plenum  30   b ), is only accessible via the gap  38  in the open top of the plenum. 
         [0035]    Turning now to  FIG. 2 , there is shown a top view of the skimmer of  FIG. 1 . According to this view, it is seen how the size and placement of the float platform  14  and the plenum  30  create a gap  38 . This gap  38  allows a liquid or matter to flow into the plenum space. 
         [0036]    The plenum  30  may be generally the same shape as the float platform  14  and is slightly larger in length and width than the float platform  14 , such that the sidewalls  30   b  of the plenum  30  are outside the physical dimensions of the float platform  14 . Thus, a gap, or inlet,  38  is present between the plenum sidewalls  30   b  and the sides of the float platform  14 . Although shown as rectangular in the figures, the plenum  30  and float platform  14  may be other shapes such as round, oval, square, etc. 
         [0037]    Furthermore, while the plenum may be generally the same shape as the float platform, it is not necessary for the plenum and the float platform to be generally the same shape. Depending on the circumstances, the plenum and float platform shape and size may be chosen. The larger the difference between the shape and size of the plenum and the float platform, the larger inlet  38  will be. For example, if a rather small inlet is desired, the plenum and float platform may be chosen to be of a generally same shape with the plenum being only slightly larger in length and width than the float platform. Additionally, the total size of the skimmer may be varied depending on the outcomes desired. For example, on a small pond, the skimmer would be of a smaller construction. For a large body of water, the skimmer may be designed large enough to hold a diesel-driven pump or even to be manned. 
         [0038]    The float platform  14  is of an appropriate size and density to support the weight of the plenum  30  and pump  18 , keeping the top of the float platform  14   a  and the pump  18  out of the liquid. The float platform  14  may typically be hollow plastic or rigid closed-cell foam. The plenum  30  is typically sheet metal or steel plate, but may be constructed of any suitable material. 
         [0039]    Turning now to  FIG. 3A , there is shown a cut-away diagram of the skimmer device taken along the dashed line III of  FIG. 2 . As seen in this figure, the tops of the plenum sidewalls  30   b  terminate at a constant, or common, vertical height. 
         [0040]    In addition to the gap  38  which allows liquid or matter to flow into the plenum or sump  30 , a gap  42  is also present between the bottom of the float platform  14   b  and the plenum bottom  30   a.  Thus, the plenum  30  forms a semi-enclosed plenum space  42  between the plenum  30  and the float platform  14 . This plenum space serves as a collecting container for the liquid or matter that flows over the plenum sidewalls  30   b  into the plenum space  42  via inlet  38 . 
         [0041]    The plenum and float platform are attached through attachment members  34 . The attachment members  34  may engage the plenum  30  and extend through the bottom of the float platform  14   b  to the top of the float platform  14   a,  and terminate above the float platform. The attachment members  34  may be adjustable to vary the vertical distance between the bottom of the plenum  30   a  and the float platform  14 . The attachment members  34  may simply be threaded rods  35  attached to the plenum and passing through the float platform  14 , using washers (not shown) and nuts  37  to adjust the vertical distance between the float platform  14  and plenum  30 . The attachment members may also be any type of adjustable attachment members as known in the art. For example, on a larger scale, the attachment may be accomplished through hydraulics. 
         [0042]    The plenum and float platform may be attached by a single attachment member, or multiple attachment members may be used for increased stability. Additionally, the attachment members need not attach the plenum bottom  30   a  to the float platform bottom  14   b.  For example, the attachment members could be angled and extend from the plenum sidewalls  30   b  to the sides of the float platform, or from the plenum sidewalls  30   b  to the bottom of the float platform  14   b,  etc. 
         [0043]    Adjustment of the attachment members allows for various distances between the bottom of the plenum  30   a  and the bottom of the float platform  14   b.  More importantly, adjustment of the attachment members  34  adjusts the vertical height difference between the tops of the plenum sidewalls  30   b  and the float platform  14 . This allows the skimmer to operate at different depths, or to skim off a top layer of liquid at various depths. 
         [0044]      FIGS. 3A and 3B  show diagrams of a side cut-away view of the skimmer taken along line III of  FIG. 2  at two different skimming depths to illustrate the adjustable feature of the device. In  FIG. 3A , a smaller skim gap, or a more shallow depth of skimming is shown (described in detail below).  FIG. 3B  diagrams a larger skim gap, or a deeper depth of skimming (described in detail below). 
         [0045]    Turning now to  FIG. 3A , the attachment members  34  are adjusted such that there is a smaller vertical distance between the plenum bottom  30   a  and the float platform  14 . With the attachment members adjusted in this manner, the tops of the plenum sidewalls  30   b,  and thus the gap  38 , is closer vertically to the top of the float platform  14   a,  and thus closer to the surface of the liquid. In order for matter or liquid to enter the plenum space  42  via the gap or inlet  38 , it must be relatively closer to the surface of the liquid, i.e., at a relatively more shallow depth. It is also seen how this adjustment creates a smaller plenum space  42  for liquid, etc. to collect before it is pumped out via the inlet passage  22  (not shown in  FIG. 3A ). 
         [0046]    Turning now to  FIG. 3B , the attachment members  34  have been adjusted such that there is a larger vertical distance between the bottom of the plenum  30   a  and the float platform  14 . As the attachment members are adjusted to increase the vertical height difference between the bottom of the plenum  30   a  and the float platform  14 , the tops of the plenum sidewalls  30   b  and the inlet  38  are pushed farther vertically from the float platform. Thus, matter or liquid would flow into inlet  38  at a lower depth. This adjustment also creates a larger plenum space  42  for the liquid to collect before it is pumped out via the inlet passage  22  (not shown in  FIG. 3B ). 
         [0047]    As the attachment members are adjusted to decrease or increase the vertical height difference between the tops of the plenum sidewalls  30   b  and the float platform  14 , the inlet  38  is pushed closer or farther vertically from the platform. Thus, the present invention may operate at a precise “skim gap”: the inlet is able to operate at a precise level of submergence to skim the top liquid layer from the surface of the water. If the top liquid layer is thicker, the skim gap may be increased to skim from a lower depth. If the top liquid layer is thinner, the skim gap may be decreased to skim from a higher depth. 
         [0048]    Turning now to  FIG. 4 , there is shown the skimmer  10  in use in a liquid body. In use, the skimmer  10  is placed into a liquid body, indicated generally at  46 , with the plenum  30  submerged. The skimmer may be placed on any location at the surface of the liquid body. If wind, current, etc., are causing the liquid body to be forced in a general direction, it may be advantageous to place the skimmer at a location at the surface of the liquid body where the liquid is generally being forced. For example, if a strong wind is blowing the surface of the liquid in a northerly direction, towards the north, the skimmer could be placed at a location in a northern part of the liquid body. This may allow for faster evacuation of the top liquid layer. 
         [0049]    The liquid body  46  in  FIG. 4  includes a heavier lower liquid level  50  and a lighter upper liquid level  54 . For example, the lower liquid  50  may be water with concentrated minerals from a solar pond, and the upper liquid  54  may be fresh rainwater. Or the lower liquid may be clean water and the upper liquid may be oil or a chemical spill, etc. After placing the skimmer into the liquid body  46  at the desired location, the attachment members  34  may be adjusted such that the top of the plenum sidewalls  30   b  are below the top surface of the upper liquid  54 , and above the top surface of the lower liquid  50 . This may allow the upper liquid  54  to flow above the top of the plenum sidewalls  30   b,  between the plenum sidewalls  30   b  and float platform  14  via inlet  38 , and into the plenum space  42 . 
         [0050]    When the pump  18  is operated, the upper liquid  54  is drawn from the plenum space  42 , through the inlet passage  22  and out the outlet passage  26  to a desired receptacle (receptacle not shown). As the plenum space is emptied by the pump, additional liquid from the upper layer may flow over the plenum sidewalls  30   b  and into the plenum space  42  via inlet  38 . 
         [0051]    In operating the skimmer, there are factors to consider for setting the skim gap. Decreasing the vertical distance between the bottom of the plenum  30   a  and the float platform  14  by adjusting the attachment members will move the inlet  38  closer to the surface of the upper liquid  54 , or to a more shallow depth. This in turn will decrease the depth of the skim gap and also decrease the volume of the plenum space. With this shallower skim depth, a slower pumping rate may be necessary because a faster pumping rate may pump the plenum space  42  dry. However, the shallower skim depth also allows more of the upper liquid  54  to be withdrawn before the lower liquid  50  is drawn into the plenum space  42  and evacuated by pump  18 . 
         [0052]    In contrast, placing the plenum  30  farther below the surface of the upper liquid  54 , i.e., at a lower skim gap, will increase the volume of the plenum space  42  and may allow for a faster pumping rate. However, this lower skim gap also reduces the amount of the upper liquid which can be withdrawn before the lower liquid  50  is drawn into the plenum space  42  and evacuated by the pump  18 . In some settings, it may be desirable to set the skim gap at a lower depth for a fast pump rate, and then adjust the attachment members  34  for a shallower skim gap as the upper liquid depth decreases. 
         [0053]    The skimmer  10  is used in many situations. For solar or evaporation ponds, the skimmer can be used to remove rain water from the pond so that the evaporation of the rain water does not delay the production of minerals from the pond. The skimmer can be used to remove oil or chemicals from off of a waterway. The skimmer can be used to remove algae or organics from a pond. 
         [0054]    There is thus disclosed an improved pond surface skimmer and decanter and method of use. It will be appreciated that numerous changes may be made to the present invention without departing from the scope of the claims.