Abstract:
A partitioning sediment trap adapted to be positioned in a body of water comprising an elongate, vertically alignable transparent collecting tube having an open upper end and a closed lower end for collecting, over a longer period of time, natural materials, contaminants, and polluting substances that accumulate in the body of water. A generally funnel-shaped cone is positioned with the small diameter end thereof extending into the open end of the collecting tube to magnify the amount of material collected. Means are also provided for automatically and efficiently partitioning and isolating undisturbed material accumulated in the collecting tube at regular time intervals.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The above titled application is a significant improvement upon prior patents U.S. Pat. No. 3,715,913 (Aquatic Sediment and Pollution Monitor), and U.S. Pat. No. 4,321,823 (Aquatic Sediment and Current Monitor) previously issued to the above applicant. The above titled application is not related to or referenced to any other prior or pending applications. 
   FEDERAL SPONSORSHIP 
   Not Applicable. 
   SEQUENCE LISTING OR PROGRAM 
   Not Applicable 
   BACKGROUND OF INVENTION 
   1. Field of Invention 
   The present invention relates to the collection and measurement of natural materials, contaminants, and polluting substances that accumulate in aquatic environments such as lakes, reservoirs, oceans, estuaries, and other bodies of water, and, more particularly, to apparatus positioned within bodies of water to automatically collect such materials and substances for the purpose of determining composition, rates of movement, and the general condition of water bodies. 
   2. Description of Prior Art 
   Devices referred to generally as time-series sediment traps have found widespread application in measuring the abundance of lacustrine and marine organisms such as bacteria, algae, other phytoplankton, and zooplankton. Such trapping devices have also been employed to determine the volume and flux of suspended particles such as silt, clay, and fragments of organic matter and various contaminants and polluting substances contained within or adhering to such particles. In addition, time-series sediment traps have been used to determine the point sources of natural and introduced particles as well as the time when such materials reached the location of a deployed device. Also, time-series sediment traps have been used in a wide range of scientific investigations such as the Joint Global Ocean Flux Study, an international global program to measure the flux of particles to the sea floor. Such investigations are an essential aspect of estimating the global cycling of carbon, which is related to environmental problems such as global warming. Other scientific investigations are concerned with particle movement during storms, tsunamis, and submarine landslides. Over the last three decades such devices have become a standard tool for investigating specific aquatic events, tracing pathways of pollution, and monitoring changing conditions in lakes, oceans, and estuaries. 
   Time-series sediment traps employ a cone or funnel to greatly magnify the volume of material that settles in collecting chambers and they also provide a means for collecting materials at regular time intervals. One such time-series device, developed by the present inventor, collected materials in a single, long collecting tube and marked the time intervals by periodically dropping plastic granules into the collecting tube. The present inventor was granted a utility patent for this device in 1973 by the U.S. Patent Office (U.S. Pat. No. 3,715,913, now in the public domain). This device was used in various investigations by research scientists, environmental contractors, and government agencies. Although the simple device provided by U.S. Pat. No. 3,715,913 was effective in certain situations, a failure of the marking system to isolate settled materials under some common conditions restricted its use to a limited number of applications. The problem is traceable to the granules of TEFLON® that were employed to mark time intervals. For example, if settled materials had a high fluid content, the granules settled differentially to form a poorly defined marking layer. If rates of accumulation were low, two or more marking layers were indistinguishable. A slight and often unavoidable tilting of the collecting tube after deployment resulted in the streaming of granules down one side of the collecting tube, resulting in failure to identify a time-marked interval. Upon recovery of the collecting tube uncertain boundaries between layers of granules limited the accuracy of sampling. In addition, granules required removal from a sample before measuring the volume and weight of recovered materials, but other materials were removed also, distorting the measurements of volume and bulk density. 
   The above-cited problems of an automated method for collecting aquatic materials in a single collecting tube by periodically releasing granules from a dispensing device limited the use of the method and favored a trap design in which materials are collected in individual bottles that are automatically and sequentially rotated below the narrow open end of a funnel. Although most time-series trap investigations now collect samples in many separate wide-mouth bottles or cups, this currently favored method has serious limitations. Among problems of collecting materials in multiple bottles is a failure to provide uninterrupted and undisturbed records of sediment accumulation. Continuous records of events talking place in water bodies are highly desirable because many such events are short-lived and are accompanied by abrupt changes in color, texture and composition of materials. For example, the effects of storm events, by flushing coarse particles from stream channels and by re-suspending already accumulated bottom sediments are well known, and are accompanied by changes in the physical and chemical properties of materials collected in funnel-shaped traps. Indeed, these same textural and composition changes in the water bodies are magnified in cone-shaped traps and clearly revealed in single, elongate collecting tubes. In another example, sewage outfall after heavy rains often contains contaminating substances that are confined to a “spike” and are thereafter dissipated. However, the current practice of collecting such evidence in many wide-mouth bottles or cups, and the unavoidable disturbance of collected materials during recovery fails to preserve evidence for such short-lived events. A single rotated vessel, for example, commonly collects material in 30-day intervals. But a single event such as a pollution episode may occur both before and after vessels are exchanged, thereby providing only a 60-day resolution for an event that occurred within one or a few days. 
   All of the problems and limitations of currently deployed, funnel-shaped, multiple-vessel, sediment trapping devices, with respect to loss of continuity and preservation of structures, textures, and composition are overcome by providing an innovative and major improvement in the method of isolating aquatic materials collected in an elongate vessel. Not only does the present invention replace the need for collecting samples in many rotated vessels, it overcomes all of the problems specific to such vessels, as well as all of the problems and disadvantages previously encountered with devices that mark regular time intervals in a single, elongate collecting tube. 
   SUMMARY OF INVENTION 
   According to the present invention, there is provided an apparatus that overcomes the problems discussed above with respect to prior art systems. According to the present invention, a single, elongate, vertically aligned, and transparent tube constructed of polycarbonate, closed at the lower end and open at the upper end, is positioned at the open end to receive the narrow opening of a funnel and the apparatus is placed in a body of water for a long period of time to collect a continuous record of particulate materials. A device positioned within the funnel, hereinafter referred to as a dispensing device, is programmed to release thin, solid partitions at known time intervals, thereby effectively isolating materials that accumulate within the elongate collecting vessel and at the same time preserving textures and structures of accumulated material. 
   Materials that accumulate in the collecting vessel are separated from materials that accumulate during previous and later time intervals by circular, boat-shaped hydrodynamic partitions composed of inert plastic material. Partitions have a high specific gravity (2.16) and are provided with a navicular shape that assures a controlled descent and horizontal orientation within the funnel and within the vertically aligned collecting tube. The rate of descent of the partitioning device is further controlled by providing an appropriate diameter for the partition relative to the inner diameter of the collecting vessel, thereby the partition settles slowly and gently in a horizontal position on the upper surface of previously accumulated and undisturbed materials. 
   OBJECTS, FEATURES, AND ADVANTAGES 
   It is therefore the object of the present invention to solve the problems encountered heretofore with the automated collection of suspended materials in bodies of water in a predetermined time series. It is a feature of this invention to solve these problems by amplifying the settling rate of particulate materials, by continuously accumulating such materials in a single vessel, by preserving the structures and textures imparted to such materials by processes operating within a water body, and by effectively isolating accumulations of particulate material in predetermined time intervals. 
   The present invention, by employing a navicular partition to isolate intervals of particulate material, overcomes the disadvantages of previous devices by isolating the accumulated material with solid, horizontally emplaced partitions. Whereas a flat disk falls edgewise in a vertical collecting tube at rates exceeding 20 cm/second and lodges in underlying accumulated particles, a navicular partition maintains a generally horizontal orientation and settles in the collecting tube at about 1 cm/second. The rate of settling is regulated by changing the space between the navicular partition and the inner wall of the collecting tube, thereby controlling the upward escape of water displaced by the descending partition. As a result, the partition comes to rest gently and horizontally on the upper surface of previously settled and undisturbed particles. Not only are underlying particles essentially undisturbed, the hydrodynamic form of the navicular partition provides a small chamber for the isolation of particles even when the rate of particle accumulation is extremely low. 
   Critical to certain investigations in aquatic environments are undisturbed structures, textures, and compositional differences that are the result of events taking place in the water body. For example, a thin layer of coarse and fine particles, positioned above the first-emplaced partition in  FIG. 1B  of the drawings, reveals textural changes typical of those preserved in a transparent and elongate collecting tube after a brief storm. Such features provide for the detailed examination and interpretation of events in a water body through the preservation of features such as particle color, composition, size, texture, and structure. Hence, the effects of currents, storms, tsunamis, sewage outfall, plankton blooms, dredging, and other events occurring in water bodies can be traced to known causes, and the timing of such events can be more precisely determined by noting the position of such features relative to partitions emplaced at known time intervals. 
   The combination of a magnified rate of particle accumulation in a single elongate collecting tube and isolating such materials with solid partitions provides a means for sampling and analyzing specific, short-term events in water bodies. For example, high concentrations of contaminating substances are commonly restricted to a particular layer, color, or texture found between partitions emplaced at known time intervals. These delicate layers and features are commonly destroyed by during recovery operations if collected in wide-mouth bottles in which materials necessarily have a high fluid content. In contrast, materials collected in a single tube and separated by navicular partitions become dewatered and compacted over time, thereby preserving delicate features for later examination and analysis. In fact, delicate structures remain undisturbed in elongate tubes that are recovered and transported in a nearly horizontal position. Hence, the combined use of navicular partitions and a single transparent collecting tube represents a significant improvement over prior art methods of automatically collecting materials suspended in water bodies. 
   Still another advantage of the present invention is the small size and simple design of the dispensing device, as compared to more complex apparatus that employ multiple collecting vessels. Furthermore, the behavior of navicular partitions is independent of size and diameter and is therefore adaptable to a wide range of funnel sizes, collecting tube diameters, ratios of magnification, and conditions of deployment, thereby potentially extending applications of the method and expanding investigations of environmental problems in water bodies. 

   
     Still other objects, features, and advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment and the accompanying drawings, wherein like numerals designate like parts in the several figures: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is an isometric view, partly cut away, of a preferred embodiment of a partitioning sediment trap;  FIG. 1B  is an enlarged view of the lower portion of  FIG. 1A ; 
       FIG. 2  is an enlarged sectional view taken through the center of the dispensing device incorporated within the structure of  FIG. 1 ; 
       FIG. 3  is a perspective view, partly cut away, of the partitioning navicular structure released from the dispensing device of  FIG. 1  and  FIG. 2 ; 
       FIG. 4A  and  FIG. 4B  are enlarged sectional views of a portion of dispensing device of  FIG. 2 ; and 
       FIG. 5A  and  FIG. 5B  are perspective views of a portion of dispensing device of  FIG. 2 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1A and 1B  of the drawings, there is shown a partitioning sediment trap, generally designated  1 , which has several components in common with the aquatic sediment and pollution monitor described and claimed in my prior U.S. Pat. No. 3,715,913. More specifically, partitioning sediment trap  1  includes a collecting tube  2  having an open upper end and a closed lower end for collecting and storing, over a relatively long period of time, materials, contaminants, and pollutants in a water body. Collecting tube  2  is positioned within a housing tube  3  which is connected adjacent the small diameter end of a cone  4  that magnifies the rate of accumulation of suspended particles  5 . The small diameter end of the magnifying cone  4  extends into the collecting tube  2 , which is held in position by the housing tube  3 . Suspended particles  5  in the water body entering the large diameter opening of the magnifying cone  4  come to rest as settled particles  6  above the lower closed end of the collecting tube  2 . 
   According to the preferred embodiment of the present invention, partitioning sediment trap  1  includes a dispensing device  7  for automatically marking, at regular intervals, the quantity of sediment accumulated in collecting tube  2  during such intervals. According to the embodiment of  FIG. 1A , dispensing device  7  is positioned within a cylindrical extension of the upper part of magnifying cone  4 . As will be discussed in greater detail hereinafter, and illustrated in  FIG. 2 , dispensing device, generally designated  7 , includes a magazine chamber  19  containing many navicular partition structures  8  having a density greater than water. Rotation of a large-diameter chamber, hereinafter designated a partition trap  22 , configured as an integral part of a rotor  20 , transfers a partition  8  from the magazine chamber  19  to partition trap  22  positioned below and aligned with magazine chamber  19 . Further rotation transfers partition to a release chamber  28  whereupon the partition  8  descends in a controlled manner, passes through the lower, small opening of the magnifying cone  4  and comes to rest horizontally on the upper surface of previously accumulated particles  6  within the collecting tube  2 . Means to rotate the rotor  20  at regular time intervals and a plurality of partitions  8  within the magazine chamber  19  thereby provide partitions between accumulated particles  6  for many known time intervals. Later recovery of the partitioning sediment trap  1  provides sufficient material for collection and analysis for which the precise time of accumulation is known. 
   Referring now to  FIG. 2 , a preferred embodiment of dispensing device  7  includes a tubular body  9  constructed of material with sufficient strength to resist pressure. The upper end of the tubular body  9  is terminated by an upper cap  10 , which is sealed with a static o-ring  11  and secured to the tubular body  9  by appropriate machine screws. A conical shield  12  is an integral part of the upper cap  10 , near the top of which is provided a hole  13  of sufficient diameter to suspend the dispensing device  7  from a supporting structure within the cylindrical extension of magnifying cone  4 . The lower end of the tubular body  9  is closed by a lower cap  14 , which is sealed within the tubular body  9  by a static o-ring  11 . The center of the lower cap is provided with a shaft hole  15  for receiving a rotating shaft  16 , which is sealed within the lower cap  14  by a dynamic o-ring  17 . The static o-rings  11  and the dynamic o-ring  17  provide seals that assure a water-tight interior within the tubular body  9  when submerged under high pressure. 
   Referring again to  FIG. 2 , a cylindrical magazine block  18  is provided with a centrally positioned shaft hole  15 , and a cylindrical magazine chamber  19  is provided between the shaft hole  15  and the outer diameter of the magazine block  18 . The magazine block  18  is positioned adjacent to the lower, outer surface of the lower cap  14  and bolted to the cap  14  with appropriate machine screws. The shaft  16  is attached to a circular rotor  20 , which contains the partition trap  22 , and rotor is secured to shaft by a rotor mounting screw  21 . 
   Referring once again to  FIG. 2 , the rotor assembly  16 ,  20 ,  21  is positioned within the shaft hole  15  aligned with the center of a cylindrical magazine cap  23 , which is provided with a central screw-head chamber  24  for receiving the head of the mounting screw  21  of aforementioned rotor assembly. A connector  25  at the upper end of shaft  16  connects the shaft to the drive shaft of a direct current gearmotor  26  aligned with the axis of shaft  16  and bolted to a mounting block  27  by appropriate machine screws. The magazine cap  23  is provided with a large opening herinafter referred to as a release chamber  28 , of the same planar dimensions as the partition trap  22  and positioned 180 degrees with respect to axis of shaft hole  15  and magazine chamber  19 . Prior to use, partitions  8  are placed within magazine chamber  19  by removing a large circular plug  29  in the magazine cap  23  that is held in place by appropriate machine screws. 
   Referring specifically to  FIG. 3 , a navicular partition, generally designated  8 , has a circular outline in plan view. The partition  8  is constructed to provide an inner body  30  from which projects a thin, upward-directed flange  31  around the perimeter of inner body  30 . A depression  32  and dome  33  in the central portion of inner body  30  are constructed to have the same vertical thickness dimension above inner body  30  as the vertical thickness of flange  31  below inner body  30  in sectional view, thereby providing a partition  8  having a generally navicular shape for which the convex surface is directed downward and concave surface and flange  31  are directed upward during free-fall through water within the magnifying cone  4  and collecting tube  2 . 
   Referring to  FIGS. 2 and 4A , and to the operation of the dispensing device  7 , the lowermost of a plurality of navicular partitions  8  within the magazine chamber  19  rests within the partition trap  22  at the start of a dispensing cycle. Commercially available electronic timing circuitry and battery power  34  housed inside the water-tight tubular body  9  of the dispensing device  7  sends an electrical current through the closed pole of a commercially available microswitch  35 , thereby turning the gearmotor  26 , connector  25 , shaft  16 , rotor  20  and integral partition trap  22  containing the lowermost partition  8  previously placed in magazine chamber  19 . Rotation of the rotor  20  and leading edge of partition trap  22  engages the edge of lowermost partition, which is transferred to the release chamber  28  upon rotation of 180 degrees. 
   Referring to  FIG. 4B , there is provided a single deflector  35  positioned opposite the direction of motion of rotor  20 , projecting part way into release chamber  28 , and affixed to lower surface of magazine cap  23  by appropriate machine screws. Referring to  FIGS. 4B ,  5 A, and  5 B, partition  8  is transferred to release chamber  28  by rotary motion of partition trap  22  and thereafter is directed downward by force of gravity and strikes deflector  35 , thereby titling partition, accelerating downward movement and application of hydrodynamic forces, whereupon partition  8  becomes hydrodynamically stable when the convex surface reaches a convex-downward horizontal orientation after a free fall of about 15 centimeters. Partition  8  descends in magnifying cone  4  in a generally horizontal orientation with the dome  33  facing downward and enters the collecting tube  2  in the same orientation. Thereafter, rate of descent of navicular partition  8  in collecting tube  2  is retarded by upward flow of water between solid partition  8  and inner wall of collecting tube  2  and partition comes to rest horizontally on upper surface of previously settled particles  6 . 
   Referring again to  FIGS. 2 and 1 , continued closure of electrical circuit and operation of gearmotor  26  rotates shaft connector  25  until microswitch  36  acted upon by continued rotation of timing cam  37  interrupts electrical circuit after particle trap  22  completes a 360-degree rotation and is repositioned below the magazine chamber  19 . Gravity acting upon other partitions  8  in magazine chamber  19  automatically moves the lowermost partition  8  into partition trap  22 , completing a cycle of operation. Continued operation of timing circuitry  34  periodically activates subsequent cycles and provides the release of additional partitions  8  and collection of suspended particles  5 ,  6  in a time series. 
   It can, therefore, be seen that in accordance with the present invention there is provided an efficient apparatus for magnifying, collecting, and determining the volume or quantity of natural materials, contaminants, and polluting substances suspended in water bodies. The present partitioning sediment trap serves to completely replace inefficient structures of prior art collecting and measuring methods. Not only is the present apparatus more efficient in isolating materials that accumulate in a single, elongate vessel, employment of boat-shaped partitions completely eliminates uncertainty in the timing of collection intervals. Furthermore, the specific gravity and hydrodynamic properties of the isolating partitions provides for the controlled descent of separating discs and providing gentle and horizontal emplacement of separating layers without disturbing previously accumulated materials and structures. Dewatering of materials in a single tube containing partitions prevents disturbance of original structures. In addition, use of solid partitions eliminates problems associated with the removal of marking materials before analysis. Importantly, the present invention, by employing a single transparent collecting tube, in conjunction with the gentle emplacement of solid partitions, provides for both the collection of materials in a time series and the preservation of physical features imparted to such materials by events taking place in a water body. The improved method provides a simple, inexpensive automatic dispensing device for a wide range of applications whereby aquatic materials are collected in a time series, thereby potentially increasing the number and scope of investigations pertaining to the general health and use of water bodies. 
   While the invention has been described with respect to a preferred physical embodiment constructed in accordance therewith, it will be apparent to those skilled in the art that various modifications and improvement may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiment, but only by the scope of the appended claims.