Abstract:
The present invention is directed to a method and apparatus for manually sampling a fluid source in a well, comprising an act of lowering a tube containing containers and container caps into a fluid in the well to allow said fluid to pass from the well into the tube to fill at least a portion of the tube such that the containers and container caps are submerged in the fluid, retrieving the tube; and closing the containers with the container caps while still submerged in the fluid.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of Provisional Patent Application No. 60/547,343, filed Feb. 25, 2004. 
     
    
     STATEMENT REGARDING FED SPONSORED R&amp;D  
       [0002]     Not applicable.  
       REFERENCE TO SEQUENTIAL LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX  
       [0003]     Not applicable.  
       FIELD OF THE INVENTION  
       [0004]     The present invention relates to methods, apparatus, and systems for sampling of a fluid source.  
       BACKGROUND OF THE INVENTION  
       [0005]     The present invention relates to a well and groundwater sampling. Wells are used in the environmental and water supply industries, among other things, to collect samples of groundwater for chemical analysis. A typical well, shown in  FIG. 1 , is comprised of a slotted section of pipe  1  (the “well screen”) located at the bottom of the well, a well point  2  which plugs the bottom of the well screen  1 , and sections of solid pipe  3  (the “riser pipe”) which thread onto the well screen  1  and each other to bring the well to the ground surface  4 . The slots in the well screen  1  are narrow enough (e.g., on the order of hundredths of an inch) to keep out soil particles, but allow in groundwater. The water level within a well having a portion of a well screen  1  above a water table  5  (e.g., water table well  6 ) is the same as the level of the water table  5  since atmospheric pressure alone is acting equally on both. If the entire well screen  1  is located beneath the water table  5  (e.g., deep well  7 ), additional pressures act on the groundwater. The pressures acting on a unit measure of groundwater are referred to as “head pressure”. Groundwater will flow from areas of high head pressure to areas of low head pressure. Groundwater entering a deep well  7  will usually flow upward into the riser pipe  3  until it reaches equilibrium. The water level at equilibrium is sometimes referred to as the piezometric surface  8 . The piezometric surface  8  in a deep well  7  is not necessary the same as the water table  5 .  
         [0006]     Significant mixing or agitation of the groundwater in a well during sample collection can result in loss of volatile compounds (volatiles) to the air column  9 , or introduction of contaminant-laden particulates or colloids into the sample. Conventional sample collection methods also may release volatiles to the atmosphere during the transfer of the groundwater into sample containers at the ground surface  4 . One conventional method that may release volatiles into the atmosphere consists of the use of a bailer. Bailers are typically short tubes that with a check ball inside that will either pass fluid through the bailer or retain fluid. Conventional check balls have a specific gravity greater than water, but can be displaced by the force of the inflowing water. Therefore, as long as the bailer sinks, groundwater passes through the bailer. When the bailer is retrieved, the check ball blocks the bottom opening and retains the water in the bailer. The collected water must then be transferred (typically by pouring) from the bailer into laboratory-acceptable containers at the ground surface. This is when significant loss of volatiles may occur due to: 1) mixing and agitation of the water as it is poured into containers; 2) the water is transferred slowly and as a relatively thin “ribbon” or stream which creates a large cumulative surface area from which volatiles can escape; and 3) the time from when the bailer is removed from the groundwater until the containers are filled at the ground surface is relatively lengthy. The present invention comprises a method and apparatus to sample groundwater that minimizes loss of volatiles and entrainment of particulates and colloids.  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     One illustrative embodiment of the invention is directed to a method for manually sampling a fluid source in a well, comprising an act of lowering a tube containing laboratory-acceptable containers (hereinafter containers) and container caps into a fluid in the well to allow said fluid to pass from the well into the tube to fill at least a portion of the tube such that the containers and container caps are submerged in the fluid.  
         [0008]     Another illustrative embodiment of the invention is directed to a container open at both ends to allow fluid to pass through.  
         [0009]     Another illustrative embodiment of the invention is directed to a container threaded at both ends so that said container can be closed and sealed with threaded container caps.  
         [0010]     Another illustrative embodiment of the invention is directed to a method to secure the container caps inside perforated sleeves (hereinafter referred to as sleeves) by binding the sleeves around the container caps with ties.  
         [0011]     Another illustrative embodiment of the invention is directed to a method to position a container inside a sleeve so that a gap remains between the container cap and container. The act of leaving a gap allows a fluid to pass through the container.  
         [0012]     Another illustrative embodiment of the invention is directed to placing a top sleeve over the threads of a bottom container and resting the top sleeve on the shoulder of the bottom container. The act of so positioning the top sleeve on the bottom container shoulder maintains a gap between the bottom container and the container cap which is bound in the top sleeve. The act of so positioning also allows “stacking” of containers and container caps in series so that a fluid can flow through multiple containers.  
         [0013]     Another illustrative embodiment of the invention is directed to a tube comprised of two sections connected at a coupling.  
         [0014]     Another illustrative embodiment of the invention is directed to a tube with a floatable check ball that allows fluid in when the tube is lowered (check ball is “unseated”) and prevents fluid from escaping when the tube is retrieved (check ball is “seated”). The check ball has a specific gravity slightly less than the fluid. Therefore, it floats off the “seat” as the tube is lowered into the fluid. This advantageously opens the tube to allow water to pass through unobstructed (i.e., when the tube is lowered), or to allow the water inside the tube to equilibrate (e.g., chemically) with the water in the well (i.e., when the tube is left in place). This also reduces turbulence when the tube is filling since the check ball doesn&#39;t constantly sink into the inflowing water as with conventional check balls. The floatable check ball is kept in the bottom portion of the tube by a convex perforated insert that is fitted into the tube near the bottom opening. The convex shape of the insert creates a “pocket” for the floatable check ball to occupy while water is flowing into the tube. This keeps the check ball stationary and also reduces turbulence as the tube fills.  
         [0015]     Another illustrative embodiment of the invention is directed to a method for inserting containers and container caps into a section of a tube comprised of separating and rejoining the tube at a coupling.  
         [0016]     Another illustrative embodiment of the invention is directed to a method for manually capping containers submerged in a fluid inside of a section of a tube. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The drawings are not intended to be to scale. In the drawings, like elements have been given like reference characters.  
         [0018]      FIG. 1  is cross-sectional views of: (A) a typical water table well; and (B) a typical deep well.  
         [0019]      FIG. 2  is cross-sectional views of: (C) the top and bottom sections of a tube; and (D) a top view of a convex perforated insert.  
         [0020]      FIG. 3  is views of a container and container caps according to an embodiment of the invention. Cross-sectional views show: (E) the container uncapped (or open); and (F) the container capped (or closed); and (G) is a top view of a container cap.  
         [0021]      FIG. 4  is cross-sectional views of containers, container caps, sleeves, ties, and container cap extender according to an embodiment of the invention. The components are shown: (H) separated; (I) with containers and container caps positioned uncapped in sleeves and the container cap extender on the top container cap; and (J) with containers capped in sleeves.  
         [0022]      FIG. 5  is cross-sectional views of a tube with containers and container caps positioned uncapped in sleeves, and inserted into the bottom section of the tube. The tube is shown: (K) being lowered into groundwater in a well (floatable check ball unseated); and (L) being retrieved from a well (check ball seated).  
         [0023]      FIG. 6  is cross-sectional views of the tube of  FIG. 2  containing a fluid with containers, container caps, sleeves, ties, and container cap extender of  FIG. 4 (I) submerged. (M) shows the containers uncapped; and (N) shows the method for manually capping the containers. 
     
    
     DETAILED DESCRIPTION  
       [0024]     One aspect of the present invention is directed to a method and apparatus that allows a fluid to pass through containers as they are lowered into the fluid, and retains the fluid in the containers when they are retrieved. Another aspect of the present invention is directed to a method and apparatus for closing and sealing containers while the containers are submerged in a fluid. Although these two aspects of the present invention are advantageously employed together in accordance with various illustrated embodiments of the invention, the present invention is not limited in this respect, as each of these aspects of the present invention can be employed separately.  
         [0025]     One illustrative embodiment of an apparatus for allowing a fluid to pass through containers as the containers are lowered into the fluid, retaining the fluid in the containers when they are retrieved, and closing and sealing the containers while the containers are submerged in the fluid is shown in  FIGS. 2-5 .  FIG. 2  illustrates a tube  10  separated at a coupling  11 . Shown are from left to right: (C) the top section of the tube  12  with coupling  11  and suspension ring  13 , the bottom section of the tube  10  with “floatable” check ball  14  and convex perforated insert  15 ; and (D) a top view of the convex perforated insert  15 .  
         [0026]      FIG. 3  illustrates, from left to right: (E) a container  16  with open and threaded ends  17  and threaded container caps  18  with septa  19  inside; (F) a closed container  16  sealed by the septa  19  at the interface  20 ; and (G) a container cap  18  and septa  19  viewed from the top.  
         [0027]      FIG. 4  illustrates, from left to right: (H) containers  16  and container caps  18  bound in sleeves  21  by ties  22 ; (I) containers  16  positioned in sleeves  21  with a gap  23  between containers  16  and container caps  18 , the top sleeve  21  resting on the shoulder  24  of the bottom container  16 , and the container cap extender  25  on the top container cap  18 ; and (J) the containers  16  and container caps  18  threaded together and sealed by the septa  19  at the interface  20 .  
         [0028]      FIG. 5  illustrates, from left to right: (K) a tube  10  being lowered into groundwater in a water table well  5  (floatable check ball  14  unseated) with the containers  16 , container caps  18  and sleeves  21  of  FIG. 4 (I) inserted; and (L) a tube  10  being retrieved from the water table well  5  (check ball  14  seated) with the groundwater retained in the tube  10  and the containers  16  submerged.  
         [0029]      FIG. 6  illustrates, from left to right: (M) a tube  10  separated at a coupling  11  retaining a fluid  26  (i.e., check ball is seated) with a container cap extender  25  fitted onto a top container cap  18  being lowered through the fluid  26  to the top of a container  16 ; and (N) the containers  16  manually pressed  27  into the container caps  18  by the container cap extender  25  and closed by turning 28 the container cap extender  25 .  
         [0030]     To collect a groundwater sample using the present invention, the tube  10  is separated at the coupling  11  and containers  16  and container caps  18 , positioned in the open arrangement in sleeves  21  (i.e., a gap  23  is left between the containers and container caps) are inserted. The tube sections  10  and  12  are reconnected at the coupling  11  which forms a tight fit with the tube and closes the containers and container caps inside. The top container cap  18  for the top container  16  is fitted onto the top container cap extender  25  and left out of the tube  10 . A line  26  is attached to the tube  10  at the suspension ring  13 , the tube  10  is lowered on the line  26  into a well and through the groundwater in the well. As the tube  10  sinks water flows in and floats the floatable check ball  14  out of the opening. The convex perforated insert  15  keeps the floatable check ball  14  in the bottom portion of the tube  10 . The water flows through the containers  16 , and out the top of the tube  12  which is open on the sides. The tube  10  is lowered until it reaches the desired sample depth. Due to the open-ended containers  16  and the floatable check ball  14 , the water in the containers  16  is the same as the water in the well at the same depth. Pulling the line  26  up seats the check ball  14  and retrieves the tube  10 . The water from the desired sample depth is retained in the tube  10 , and hence in the containers  16  by the seated check ball  14 . At the ground surface  4 , the tube  10  is again separated at the coupling  11 . This allows access to the water in the tube  10  and allows the container cap extender  25  with the top container cap  18  to be inserted into the water and placed on the top container  16 . The containers  16  are then “collapsed” into the container caps  18  by pushing down on the container cap extender  25 . This act also expels any air in the top container caps  18 . Alternately, a small hole in the sidewall of the top container caps  18  can be made to release air as the container caps  18  are submerged. Starting with the top container  16 , the container caps  18  are then manually threaded onto the containers  16  by turning the container cap extender  25  and alternately squeezing the tube  10  to prevent containers  16  or sleeves  18  from rotating. The ties  22  prevent the container caps  18  from spinning in the sleeves  21 . However, the containers  16  can spin in the sleeves  21 . Therefore, all of the container caps  18  can be threaded onto the containers  16  by turning the container cap extender  25 .  
         [0031]     An advantage of the present invention is the open-ended containers can pass water through allowing samples to be collected at any specific depth within a water table or deep well.  
         [0032]     Another advantage of the present invention is the floatable check ball, which allows groundwater into the tube except when the tube is retrieved. This advantage over conventional bailers, which rely upon the force of the incoming water to unseat the check ball, results in less turbulence within the tube as the water enters, and allows the bailer to be lowered into the water at a very slow rate, thereby minimizing the displacement of water at the leading tip of the tube  10  to the outside of the tube  10  and maximizing pass-through of the water. When the tube is left in place in a well, this advantage also allows water inside the tube to equilibrate (e.g., chemically) with the water in the well.  
         [0033]     Another advantage of the present invention is capping the containers while still submerged significantly reduces loss of volatiles that may occur during the transfer of the water from a conventional sampler to laboratory-acceptable containers.  
         [0034]     Another advantage of the present invention is the minimization of mixing or agitating the water column. When first deployed, the tube is lowered very slowly (permissible due to the floatable check ball) through undisturbed water. Therefore, the water in the containers when retrieved is absent any appreciable particulates or colloids.  
         [0035]     Another advantage of the present invention is the cost is low enough to use it once, thus eliminating cross-contamination between wells that may occur when equipment is used more than once.  
         [0036]     Aspects of the present invention are suited for use with both water table and deep wells. It should be appreciated that although the invention has been described in the context of sampling groundwater, other fluids may alternatively be sampled according to the invention. It should further be appreciated that the materials noted for use in the apparatus described are given for example only. The tube, check ball, containers, container caps, sleeves, ties, and container cap extender may be made from a number of plastics, metals, glass, and other materials that are relatively impermeable and non-reactive.  
         [0037]     Having thus described several illustrative embodiments of the invention, various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto.