Abstract:
The present inventions provide a floating type decanter apparatus that controls the decanting operation through the use of air.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 10/940,807, filed on Sep. 13, 2004, now U.S. Pat. No. 7,083,716. 

   FIELD OF THE INVENTIONS 
   The present inventions relate generally to floating decanters for removing supernate from near the top of a liquid surface. More particularly, the present inventions relate to floating decanters that selectively perform the decanting operation through the use of air. 
   BACKGROUND OF THE INVENTIONS 
   Decanters are well known, particularly in the water and wastewater treatment industry. In wastewater treatment, for example, decanters are often used to remove the clarified liquid above the settled solids in a sequencing batch reactor treatment process. In general, there are fixed and floating type decanters. Examples of floating decanters are described and referenced in U.S. Pat. Nos. 4,695,376 and 5,104,528. Some such decanters require mechanical, electromechanical or pneumatic actuators to start and/or stop the decanting operation. Other floating decanters, such as those taught in U.S. Pat. No. 5,358,644 require, among other things, the priming or filling of the decanter line assembly to initiate the decanting operation. A representative example of known fixed decanters are described and referenced in U.S. Pat. No. 4,883,602. 
   SUMMARY OF THE INVENTIONS 
   The present inventions provide novel and effective floating decanting assemblies and devices that can be used in a variety of applications, while at the same time preserving the advantages of known decanters. 
   Accordingly, an object of the present invention is to provide a floating decanter that is activated by air (or other gas) and does not require mechanical actuation or priming the decant line. 
   Another object of the present invention is to provide an air operated decanter that requires little or no service or maintenance within the decant basin. 
   Still another object of the present invention is to provide an air activated floating decanter that is of a relatively low profile and/or can be used in covered and uncovered environments, including explosive and/or hazardous applications. 
   A further object of the present invention is to provide an air decanter that effectively removes supernate and prevents the flow of scum or other surface debris from entering the decanting operation. 
   Still another object of the present invention is to provide a floating decanter that selectively conducts the decant operation using relatively low pressure air (or other gas) from a wide variety of available sources. 
   Yet another object of the present invention is to provide a decanter that includes various means to operatively couple the decant pan to the float or upper portion. 
   Yet an additional object of the present invention is to provide a floating decanter that may be a variety of shapes, such as round, rectangular, oval and the like. 
   Accordingly, the present invention provides a floating decanter for selectively performing the decanting operation in a decant basin and discharging supernate through a decant line assembly, having an upper portion including at least one float, a guide and a stop; a lower portion including a decant pan forming a buoyancy chamber, the decant pan operatively coupled to said upper portion; a discharge opening on the decant pan in fluid communication with the decant line assembly; and, an air line in communication with the buoyancy chamber for permitting the selective activation or deactivation of the decanting operation through the controlled evacuation or introduction of air into the buoyancy chamber. The present invention may also include a trap on the air line to prevent the introduction of water; a recess on the lower side of the float that is sized to permit the exterior upper surface of the decant pan to extend into the recess on the float when no decanting operation is being conducted; at least one ballast weight on the decant pan; and, a main air (or other gas) supply line in fluid communication with the air line that is connected to a low pressure air supply source. 
   Also according to the present invention, a floating decanter assembly to selectively permit the decanting operation in a decant basin is provided, having at least one float with a lower surface; a decant pan having an upper exterior surface capable of engaging the lower surface of the float and operatively coupled to the float using a linkage assembly to be capable of separating from the lower surface of the float a predetermined distance; a buoyancy chamber formed on a lower surface of the decant pan; a decant line assembly; an air line in communication with the buoyancy chamber; a discharge opening on the decant pan in communication with the decant line assembly; and, a main air supply assembly in communication with the air line. 
   And, the present invention provides a floating decanter assembly for performing decanting operations in a decant basin, the assembly having an upper portion including a float; a lower portion including a decant pan forming a buoyancy chamber and a discharge opening; a decant line assembly in communication with the discharge opening; and, an air supply means for selectively evacuating or introducing air in the buoyancy chamber for controlling the activation or deactivation of the decanting operation. A linkage assembly means for operatively coupling the upper portion to the lower portion is also provided. 
   DEFINITION OF THE TERMS 
   The following terms which may be used in the various claims and/or specification of this patent are intended to have their broadest meaning consistent with the requirements of law: 
   Decant basin: The liquid retaining receptacle for performing the decanting operation that may include open or covered basins, tanks, ponds or lagoons. 
   Decanting operation: The selective removal of supernatant or other separated fluid from near the top of a liquid surface in a decant basin and transferring it as effluent to some other location. 
   Float: The component(s) that maintains a degree of positive buoyancy of the decanter assembly in the decant basin during various phases of the decanting operation. The float may be in the form of an annulus having a variety of shapes and which may be constructed of metal, stainless steel, fiberglass, plastic and the like. 
   Decant line assembly: The piping, connectors, valves and other components that receive the supernatant or decanted liquid during the decanting operation and remove the decanted liquid effluent from the decant basin. The decant line is typically constructed from flexible pipe and/or couplings of any suitable material so that the line may move as part of the decanter assembly to accommodate changing liquid levels in the decant basin. 
   Decanter assembly: The components within the decant basin that are used to perform the decanting operation and which is in communication with the decant line assembly. 
   Where alternative meanings are possible, in either the specification or claims, the broadest meaning is intended. All words used in the claims are intended to be used in the normal, customary usage of grammar, the trade and the English language. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above described objects, features and advantages, as well as other features and advantages, of the present inventions (sometimes used in the singular, but not excluding the plural) will become apparent by reference to the specification and drawings; wherein like reference numbers are used for like elements among the several views, and in which: 
       FIG. 1  is a bottom perspective view of a decanter assembly of the present invention; 
       FIG. 2  is a bottom perspective view of an upper portion of a decanter assembly of the present invention; 
       FIG. 3  is a top perspective view of a decant pan and other components of the present invention; 
       FIG. 4  is a bottom perspective view of a decanter assembly of the present invention which is similar to the view of  FIG. 1 ; 
       FIG. 5  is a sectional view of a decanter apparatus of the present invention shown in a closed or inactive state; 
       FIG. 6  is a sectional view of the decanter apparatus of  FIG. 5  shown in a position at the initiation of the decanting operation; 
       FIG. 7  is a sectional view of the decanter apparatus of  FIG. 5  shown in a position during full decanting operation; 
       FIG. 8  is a sectional view of the decanter apparatus of  FIG. 5  shown in a position at the stopping of the decanting operation; 
       FIG. 9  is a top plan view of the decanter apparatus of  FIG. 5 ; 
       FIG. 10  is a top perspective view of an embodiment of a decant assembly, including an alternative embodiment of an operative coupling shown in an open or decant position; 
       FIG. 11  is a top perspective view of the present invention of  FIG. 10  shown in a closed or inactive position; 
       FIG. 12  is a top perspective view of components of an alternative embodiment of an operative coupling of the present invention shown in an open or decant position; 
       FIG. 13  is a top perspective view of the embodiment of  FIG. 12  of the present invention shown in a closed or inactive position. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Set forth below is a description of what is currently believed to be the preferred embodiments or best representative examples of the inventions claimed. Future and present alternatives and modifications to the preferred embodiments are contemplated. Any alternatives or modifications which make insubstantial changes in function, purpose, structure, use or result are intended to be covered by the claims of this patent. 
   A decanter assembly  10  of the present invention may be used in a decant basin  12 , such as a tank, having side walls  14  (see e.g.,  FIGS. 5-8 ). The decant basin  12  has a water level  16  that changes throughout the decanting operation. Decanter assembly  10  generally includes an upper portion  20  and a lower portion  30 . The decanter assembly  10  may be moored within decant basin  12  by a variety of mooring means well known to those of skill in the art. For example, mooring posts  15  may be provided within basin  12 . Mooring posts  15  may be slidingly engaged by mooring guides  17  which may be attached to upper portion  20  (see e.g.,  FIGS. 5-9 ). 
   As seen by reference to  FIG. 2 , upper portion  20  includes a float  21 . Float  21  may be in the form of an annulus having an upper annular surface  22 , an outer side surface  23 , an inner side surface  24  and a lower annular surface  25 . In a preferred embodiment, lower annular surface  25  is provided with a recess  26 , the shape of which corresponds to the shape of the exterior upper surface  34  of decant pan  32 , as hereinafter described. Lower surface  25  of float  21  is also provided with guides  27  having stops  28 . The guides  27  and stops  28  are used to be slidingly engaged by and align lower portion  30  to upper portion  20 . In addition, guides  27  and stops  28  limit the amount of separation or gap  29  ( FIGS. 7 and 8 ) between float  21  and decant pan  32 , as hereinafter described. Upper portion  20  may, if desired, be provided with a removable lid or cover  19  that, as shown in  FIGS. 5-9 , may be placed on upper surface  22  of float  21 . 
   The principal components of lower portion  30  of decanter assembly  10  may be best seen by reference to  FIGS. 1 ,  3  and  4 . Lower portion  30  includes a decant pan  32  which is in fluid communication with a decant line assembly  50  shown in  FIG. 5-9 . In a preferred embodiment, decant pan  32  includes an exterior upper surface  34  and an exterior side surface  35 . Decant pan  32  also includes an interior upper surface  36  and an interior side surface  37 . These surfaces are assembled to form a buoyancy chamber  33  on the underside of decant pan  32  that enables the selective control of the decanting operation by adding air (or other gas) to or evacuating air (or other gas) from buoyancy chamber  33 , as hereinafter described. Decant pan  32  is shown as having a circular footprint when viewed from above or below. However, any shape/footprint, such as a square or rectangle, may be used as long as sufficient buoyancy may be maintained in the buoyancy chamber  33  created by decant pan  32 , as hereinafter described (see e.g.,  FIGS. 10-13 ). A lip  38  ( FIG. 3 ) is provided on exterior upper surface  34  of decant pan  32  to engage recess  26  of float  21  when no decanting operation is being conducted, as hereinafter described. Lip  38  also functions as a weir and may also be configured to help control the flow over exterior upper surface  34 . 
   A discharge opening  40  is provided on decant pan  32  between the exterior upper surface  34  and the interior upper surface  36  ( FIG. 3 ) that conveys the flow of decant liquid to decant line assembly  50 . Discharge opening  40  is sealingly coupled to a discharge pipe  41  that includes a flange  42  which in turn is flexibly coupled to decant line assembly  50 . A baffle, weir or other flow control mechanism  31  may be provided on exterior upper surface  34  that cooperates with discharge opening  40  to prevent vortices and the like during the decanting operation. A series of ribs  39  may be provided in buoyancy chamber  33  to help strengthen and support the decant pan  32 , discharge pipe  41  and other components. And, as discussed below, buoyancy chamber  33  may be divided into a number of individual chambers depending upon the application. 
   Although a variety of other forms may be employed, decant pan  32  is also provided with legs  43  and ballast weights  44 . The legs  43  and associated ballast  44  are sized to counteract the buoyancy of lower portion  30 , as hereinafter described. Legs  43  may also function as a stand for decant assembly  10  when the water level  16  in tank  12  is in its lowest position. Alternatively, and as will be understood by those of skill in the art, legs  43  may interact with a shelf  11  of a dewatering stand assembly  13  ( FIGS. 5-8 ) during the dewatering process (not shown). Sleeves  45  are also provided on decant pan  32  that slidingly engage guides  27  and cooperate with stops  28  of upper portion  20 . 
   An air line  46  is also provided on decant pan  32 . One end of the air line  46  has an inlet  47  that communicates with buoyancy chamber  33  and the other end has a connecting flange manifold  48  that provides a means to connect air line  46  to a main air supply line  49  (see e.g.,  FIG. 4 ). The main air supply line  49  may run parallel or be attached to decant line assembly  50 . Main air supply line  49  is connected to pumps, valves and compressors (not shown) so that air may be selectively supplied to or evacuated from buoyancy chamber  33  via inlet  47 . In a preferred embodiment, air supply line  46  extends above the exterior upper surface  38  of decant pan  32  and through the annular opening of float  21  ( FIGS. 1 and 3 ). This trap or elbow is provided to ensure that air line  46  is kept above water level  16  at all stages of the decanting operation so that it will not fill with water. 
   Having described the major components of a preferred embodiment of the decanter assembly  10  of the present invention, its operation during the typical decanting operation may be understood by reference to  FIGS. 5-8 . 
     FIG. 5  shows the present invention in an inactive state where there is no decanting operation taking place. When in this state, buoyancy chamber  33  is substantially filled with air, displacing the water that would otherwise be in the buoyancy chamber  33  and providing buoyancy to decant pan  32 . Thus, the chamber water level  18  is roughly as shown in  FIG. 5 . Additional buoyancy is also provided to lower portion  30  from the empty decant line assembly  50 . This cumulative buoyancy is sufficient to overcome the weight of the lower portion  30 , including the legs  43  and weight  44 . At this phase, the buoyancy of the lower portion  30  is also sufficient to overcome some or all of the weight of upper portion  20 . Consequently, the exterior upper surface  34  of decant pan  32  extends into the recess  26  on lower annular surface  25  and is above water level  16 . In addition and depending upon the application, the lower annular surface  25  of float  21  may also be slightly above water level  16  (not shown) at the closed or non-decant phase. Accordingly, flow through discharge opening  40  is prohibited. In addition, because the lip  38  on the exterior upper surface  34  is above water level  16 , there is no need for a watertight seal between the exterior upper surface  34  of the decant pan  32  and lower annular surface  25  and/or recess  26  of float  21 . 
     FIG. 6  shows the present invention at the initiation of the decant operation. Specifically, when decanting is desired, air from the buoyancy chamber  33  is evacuated via inlet  47  of air line  46  and vented out of the system through main air supply line  49  and its associated valves, fittings and the like (not shown). As a result, chamber water level  18  raises by gravity and displaces the air formerly in buoyancy chamber  33 . This displacement results in loss of buoyancy of lower portion  30  and the weight of the lower portion  30  overcomes the buoyancy of the empty decant line assembly  50 . As the air in buoyancy chamber  33  is displaced by water, as shown in  FIG. 6 , upper portion  20  begins to sink lower into the water. Eventually, the loss of buoyancy will result in the separation of upper portion  20  and lower portion  30  (i.e., creating gap  29  as shown in  FIGS. 7 and 8 ), allowing decant pan  32  to sink below water level  16 . Water flowing over the lip  38  and into discharge opening  40  begins filling the decant line assembly  50 , further reducing buoyancy of lower portion  30 . 
   Lower portion  30  would continue to sink as a result of the lost buoyancy. However, the sinking of lower portion  30  is limited a predetermined amount by the stops  28  on guides  27  of upper portion  20 . When sleeves  45  on decant pan  32  engage stops  28 , lower portion  30  begins to drag upper portion  20  down into the water and a lower portion of float  21  below water level  16 . At this point, the buoyancy of float  21  is sufficient to overcome the weight of lower portion  30  when in the full stage of the decanting operation, as shown in  FIG. 7 . 
   The use of guides  27  and stops  28  on upper portion  20  in conjunction with sleeves  45  on decant pan  32  is one exemplary way to operatively couple decant pan  32  to float  21  and to control the distance of travel of decant pan  32  during the decanting operation. Other means are available as will be understood by those of ordinary skill in the art. For example, a preferred alternative method of coupling decant pan  32  to float  21  is shown in  FIGS. 10-13 . In this embodiment, a linkage assembly  60  is provided to operatively connect decant pan  32  and float  21  as well as limiting, by a predetermined amount, the travel of pan  32  from float  21 . 
   A preferred embodiment of linkage assembly  60  includes two rods  62  that are pivotably mounted to pairs of opposing linkage mounts  61 . Linkage mounts  61  may be formed from angled plates  63  that are designed to be secured to the upper annular surface  22  and the inner side surface  24  of annular float  21 . Bearings  64  are provided on the inside face  65  of angled plates  63  to rotatably mount rods  62  between opposing angled plates  63 . 
   An activation arm  66  is provided on each end of rods  62  and secured to rods  62  so that it may rotate with rods  62 . Similarly, a brace arm  67  is secured to each end of rods  62 , preferably within activation arm  66 , which is also designed to rotate with rods  62 . A brace  69  is pivotably connected to brace arms  67  between each adjacent rod  62 . Brace arms  67 , along with brace  69 , insure that rods  62  rotate together and pan  32  moves smoothly and evenly as hereinafter described. Finally, activation arm  66  is pivotably attached at its free end to decant pan  32  by legs  68 , one end of which is secured to the exterior upper surface  34  of decant pan  32 . 
   As a result of linkage assembly  60 , lower portion  30  may be separated from upper portion  20 . It will be understood by those of skill in the art that the amount of separation between upper portion  20  and lower portion  30  may be controlled by, among other things, a deterrent or stop (not shown) as part of the linkage mounts  61  and/or the length of activation arms  66 . It will also be understood that linkage assembly  60  may take a variety of configurations, such as the use of different linkage mounts  61 , brace and activation arms  67  and  66 , as well as different methods of mounting and different locations of the components. 
   Just like the other embodiments discussed herein, when no decanting is taking place, pan  32  is in contact with float  21  and linkage assembly  60  is in the position as shown in  FIGS. 11 and 13 . And, like the other discussed embodiments, when decanting is desired, air from the buoyancy chamber  33  is evacuated and is displaced by water. This displacement results in a loss of buoyancy of lower portion  30 , which begins to sink. Rods  62  and associated activation arms  66  rotate downward until arms  66  engage a stop or deterrent (not shown) and the system is then in its full stage of the decanting operation, as shown in  FIGS. 10 and 12 . When desired, the decanting operation may stopped as described herein. 
   To stop the decanting operation, air is introduced into buoyancy chamber  33  via inlet  47 . Like the reverse of initiation of the decanting operation, when ceasing the decanting operation, the introduced air displaces the water in chamber  33 , lowers chamber water level  18  and adds buoyancy to lower portion  30  as shown in  FIG. 8 . This added buoyancy is sufficient to overcome the weight of lower portion  30  and the weight of now full decant line assembly  50 . As a result, lower portion  30  begins to rise, eventually bringing lip  38  and upper surface  34  of decant pan  32  out of the water and into engagement with float  21 , as shown in  FIG. 5 , and stopping the decanting operation. 
   As will be understood by those of skill in the art, particularly in light of the teachings of this patent, the ballast weights  44  or other methods of providing ballast, in conjunction with the weight of the other components of the lower portion  30 , must be sufficient to overcome the buoyancy of the empty decant line assembly  50  when water is evacuated from buoyancy chamber  33  to initiate the decanting operation. In addition, it is preferred that the ballast weights  44  be positioned low and away from the vertical center line of the decanter assembly  10  to provide stability to the assembly  10 . As previously discussed, legs  43  may also function as or cooperate with a dewatering stand  13  for the assembly  10  when the decant basin or tank  12  is being dewatered. 
   In addition, it will also be understood by those of skill in the art that buoyancy chamber  33  must be sufficiently large to displace enough water to compensate for the buoyancy lost and weight of a full decant line assembly  50 . This enables lower portion  30  to regain positive buoyancy to stop the decanting process and empty the decant line assembly  50 . In a simple embodiment, the decanter assembly  10  settles low enough in the basin or tank  12  that effluent flow rate is determined purely by head differential between the decanter assembly  10  and discharge elevation, as will be understood by those of ordinary skill in the art. In such applications, the decant line assembly  50  runs completely full and decant flow rate decreases as basin level  16  and driving head drop. 
   In an alternative embodiment of the present invention, it is also possible to exercise a higher degree of control over the rate of discharge of effluent from the decanter assembly  10  in situations where it is required. To control the rate of discharge, the ability to control the flow over the exterior upper surface  34  must be provided. Notably, until the decant line assembly  50  runs fully flooded, flow over lip  38  and the exterior upper surface  34  of decant pan  32  is a function of both surface perimeter of the upper surface  34  and degree of submergence of decant pan  32 . If the surface perimeter component is of one elevation or flat (as shown), flow will vary essentially according to submergence to the (3/2) power. If the exterior upper surface  34  is notched (not shown), its perimeter surface area will vary with submergence, providing an added means to varying flow. In addition, since the submergence level remains a function of the overall assembly  10  buoyancy, it is also possible to form a partitioned buoyancy chamber  33  (not shown) such that the decant line assembly  50  does not run completely full (not shown). In this embodiment, additional air lines  46  are required to supply the individual buoyancy compartment(s) or individual chambers of decant pan  32  with air and to permit the evacuation of air. 
   Embodiments having increased control over discharge rate are particularly applicable when the duration of the decanting operation must be fixed regardless of decant effluent volume. In such situations, the “full flow” setting could be used initially, followed by a low flow period to stretch the decanting operation cycle to the required duration. Level sensors (not shown) within the basin  12  would allow an automatic controller to switch between the two settings as needed. 
   Moreover, as will be appreciated, once the decanting operation is initiated, it will continue until air is introduced into the buoyancy chamber  33 . Under typical circumstances, air may be supplied by blowers (not shown) that are typically used for aeration during the operation of a sequencing batch reactor or otherwise available at the water or wastewater treatment facility. In the event of a blower failure or general power failure, a standby tank of compressed air, or other back-up means (not shown), could operate the system. Generally, any low pressure air source (for example, one that supplies air at pressure sufficient to displace the water in buoyancy chamber  33  during the decanting operation in order to stop the decanting operation) used in conjunction with manual override valves controlling the main air supply line may be used that would allow operation under any circumstances. 
   Further, it will be understood that the float  21  must provide sufficient buoyancy such that the sides  23  of the float  21  become partially submerged below water line  16  during the decanting operation, but at the same time, does not sink. The partial submergence of float  21  prevents scum or other floating debris from contaminating the decanted effluent during the decanting operation. 
   The above description is not intended to limit the meaning of the words used in the following claims that define the invention. Rather, it is contemplated that future modifications in structure, function or result will exist that are not substantial changes and that all such insubstantial changes in what is claimed are intended to be covered by the claims. Thus, while preferred embodiments of the present inventions have been illustrated and described, it will be understood that changes and modifications can be made without departing from the claimed invention. In addition, although the term “claimed invention” or “present invention” is sometimes used herein in the singular, it will be understood that there are a plurality of inventions as described and claimed. 
   Various features of the present inventions are set forth in the following claims.