Abstract:
The bore hole tracer injection apparatus is a mechanical device for inserting a tracer agent into a bore hole at a predetermined depth. Outer and inner cylinders have side ports, with the side ports of the cylinders misaligned to prevent fluid escape from the inner cylinder until desired. The bottom of the inner cylinder includes a filler passage. A line passes through the top of the outer cylinder and attaches to a rod across the top of the inner cylinder, above the closed top thereof. The inner cylinder is filled with a tracer agent, and the apparatus is lowered into the bore hole to the desired depth. A weight is then dropped down the line, and jars the outer cylinder down around the inner cylinder when it contacts the top of the outer cylinder. This aligns the side ports of the cylinders to allow escape of the tracer agent therefrom.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to tools and equipment for earthen boring and subterranean wells, and particularly to a bore hole tracer injection apparatus for remotely releasing a tracer agent in the downhole of a well. 
     2. Description of the Related Art 
     The underground movement of certain fluids is of considerable importance in various fields. An example is found in the field of groundwater aquifers, where it is critical under certain conditions to determine both the direction and the velocity of subsurface flow. This is important in determining where to locate a water well(s), the possible contamination of subsurface water sources, and for various other reasons. 
     One of the means for determining such direction and velocity of flow is by drilling or otherwise forming a borehole, lowering a radioactive tracer agent into the borehole, and releasing the tracer at a predetermined desired depth in the borehole. The radioactive tracer flows from the borehole with the subsurface flow, and may be detected through suitable radiation detection devices to determine the direction and velocity of flow. However, most of the equipment that has been developed for determining such subsurface flow is directed to the petroleum industry, and is relatively costly and complex. 
     Thus, a bore hole tracer injection apparatus solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The bore hole tracer injection apparatus provides for the accurate delivery of a radioactive tracer material into a borehole at a predetermined depth, without need for costly or complex electronic mechanisms. The apparatus essentially comprises two concentric cylinders. The inner cylinder is closed with the exception of a series of ports in the side wall and a single hole in the bottom for filling the cylinder with a fluid, e.g., a radioactive tracer agent. The outer cylinder also has a series of ports in the side wall thereof, but is open at the bottom to allow the inner cylinder to be installed within the outer cylinder. 
     The outer cylinder also has a passage in its top wall to provide for the passage of a suspension line, e.g., a rope, cord, cable, wire, or similar flexible member therethrough. The suspension line is passed through the top opening or passage of the outer cylinder, and tied (or otherwise secured) to a rod that is secured diametrically across the top of the inner cylinder above its closed top wall. The rod extends through two of the side ports of the outer cylinder to assure that the two cylinders do not rotate relative to one another. 
     The apparatus is used by installing the inner cylinder partially within the outer cylinder, such that there is some space or distance between the top of the inner cylinder and the inner top of the outer cylinder. In this manner, the ports of the outer cylinder and the inner cylinder are misaligned and fluid cannot flow from the inner cylinder. In other words, the outer cylinder acts as a closure for the inner cylinder. Circumferential O-rings are provided about the outer surface of the inner cylinder and the inner surface of the outer cylinder to seal any gap that may exist between the two cylinders. The inner cylinder is then filled with a suitable tracer agent and its filler port is plugged. 
     The apparatus may then be lowered into a borehole to the desired depth, according to the length of line or cord that is paid out. When the apparatus has reached the desired depth, a weight is dropped down the suspension line and contacts the top of the outer cylinder. This jars the outer cylinder downward until its top wall contacts the top of the inner cylinder, whereupon the side ports of the outer cylinder and inner cylinder are aligned with one another. This allows the tracer agent to escape from the device to flow into the subsurface aquifer or other subsurface liquid for tracing the direction and velocity of flow of the liquid using suitable detection equipment. The assembly is then drawn upward from the borehole for reuse as desired. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a bore hole tracer injection apparatus according to the present invention, illustrating its various components and features. 
         FIG. 2A  is an elevation view in section of the bore hole tracer injection apparatus according to the present invention, showing the assembled apparatus prior to release of the tracer agent. 
         FIG. 2B  is an elevation view in section of the bore hole tracer injection apparatus according to the present invention, showing the assembled apparatus after release of the tracer agent. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The bore hole tracer injection apparatus provides a reliable, purely mechanical means for injecting a tracer agent, e.g., a radioactive liquid, etc., into the bore hole of a water or other well or downhole at a predetermined depth therein. Tracing the direction and velocity of the tracer agent as it infiltrates the subsurface aquifer or other liquid deposit enables the technician to determine the corresponding location and direction of flow of the water or other liquid below the surface. 
       FIG. 1  of the drawings provides an exploded perspective view of the components of the borehole tracer injection apparatus  10 . The apparatus  10  includes an inner cylinder  12  that installs axially and concentrically within an outer cylinder  14 . The inner cylinder  12  has a closed top wall  16  with a top  18 , i.e., an extension of the cylinder  12 , extending above the top wall  16 , and a bottom wall  20  with a filler port  22  formed therethrough. A plug  24 , e.g., resilient member, cooperatively threaded, etc., is used to selectively close and seal the filler port  22  as required for operation of the apparatus  10 . The side wall  26  of the inner cylinder  12  includes a plurality of tracer agent dispensing ports formed therethrough, with the dispensing ports preferably comprising a pair of diametrically opposed upper ports  28   a,    28   b , and a pair of diametrically opposed lower ports  30   a,    30   b.  The cylindrical side wall  24 , along with the closed top wall  16  and the bottom wall  20 , define a tracer agent container  32  therein. 
     The outer cylinder  14  has a top wall  34  with a suspension line clearance passage  36  disposed therethrough, an open bottom  38 , and a circumferential side wall  40 . The side wall  40  includes a plurality of tracer agent dispensing ports formed therethrough, as in the case of the inner cylinder  12 . The ports of the outer cylinder  14  also preferably comprise a pair of diametrically opposed upper ports  42   a,    42   b,  and a pair of diametrically opposed lower ports  44   a,    44   b.  The outer cylinder ports  42   a  through  44   b  are located or positioned to align with the corresponding upper and lower ports  28   a  through  30   b  of the inner cylinder  12  when the inner cylinder  12  is inserted completely into the outer cylinder  14 , as shown in  FIG. 2B . 
     It will be seen in  FIG. 2A  that the tracer agent container  32  defined by the inner cylinder  12  is completely closed when the inner cylinder  12  is not completely inserted into the outer cylinder  14 . In order to prevent leakage of the tracer agent between the two cylinder walls, a series of sealing rings, e.g., O-rings, etc., is installed between the two cylinders  12  and  14 . The outer surface  46  of the inner cylinder  12  includes two circumferential sealing ring grooves  48   a,    48   b  therearound, with a sealing ring, respectively  50   a  and  50   b,  seated in each of the grooves. Similarly, the inner surface  52  of the outer cylinder  14  includes two circumferential sealing ring grooves  54   a,    54   h  therearound, with each of these grooves containing a sealing ring, respectively  56   a  and  56   b.  These  0 -rings or other sealing rings seat and seal against the adjacent surface of the opposite cylinder to retain any tracer agent within the tracer agent container  32  of the inner cylinder  12  when the ports  28   a  through  30   b  of the inner cylinder  12  are not aligned with the ports  42   a  through  44   b  of the outer cylinder  14 , as shown in  FIG. 2A . The contact of the various seals or rings  50   a,    50   b,    56   a,  and  56   b  with the adjacent surface of the respective opposite cylinder also results in some frictional resistance to axial movement of the inner cylinder  12  with respect to the outer cylinder  14 . This friction holds the inner cylinder  12  in position within the outer cylinder  14  as adjusted during preparation of the apparatus  10  for use, but is not sufficient to prevent movement between the two cylinders  12  and  14  if some moderate external axial force is applied. 
       FIG. 1  of the drawings provides an exploded perspective view showing the assembly of the various components of the borehole tracer injection apparatus  10 . The apparatus  10  is assembled by inserting the inner cylinder  12  into the open bottom  38  of the outer cylinder  14  and sliding the inner cylinder  12  into the outer cylinder  14  until the top extension  18  of the inner cylinder  12  is visible through the upper ports  42   a,    42   b  of the outer cylinder  14 , generally as shown in  FIG. 2B . A rod  58  is then inserted through one of the upper ports  42   a  or  42   b  of the outer cylinder and through a pair of diametrically opposed holes or passages  60  disposed through the top extension  18  of the inner cylinder  12 , above the closed top wall  16  thereof. The ends of the rod  58  extend beyond the diameter of the inner cylinder  12  to reside in the two diametrically opposed upper ports  42   a,    42   b  of the outer cylinder  14 . In this manner, the inner and outer cylinders  12  and  14  are prevented from significant rotation relative to one another, and their respective ports are held in axial alignment with one another. 
     One end of a flexible suspension line  62 , e.g., cord, wire, cable, etc., is then passed through the line clearance passage  36  through the top wall of the outer cylinder  14 , and secured (e.g., tied, clipped, etc.) to the rod or pin  58  that is in turn secured to the top  18  of the inner cylinder  12 . (A loop or other attachment may be formed in the end of the line  62  prior to inserting the end of the line into the upper end of the outer cylinder  12  and prior to installing the rod or pin  58  through the top  18  of the inner cylinder  12 , with the rod or pin  58  then being installed to pass through the loop or other attachment of the line  62 , if it is not possible to manipulate the end of the line  62  to form a loop or attachment when the line  62  end is inside the upper portion of the outer cylinder  14 .) 
     At this point, the inner cylinder  12  is moved axially downward, i.e., away from the top wall  34  of the outer cylinder  14 , so that the various side ports of the inner and outer cylinders  12  and  14  are not aligned with one another, generally as shown in  FIG. 2A . The tracer agent container  32 , i.e., the inner volume of the inner cylinder  12 , may then be filled with a suitable tracer agent or other material as desired by removing the plug  24  from its filler port  22  in the bottom wall  20  of the inner cylinder  12  and filling the inner cylinder as desired. The plug  24  is then reinstalled in its filler port  22 . It will be seen that the tracer agent container  32 , i.e., the interior volume, of the inner cylinder  12  is sealed by the side wall  40  of the outer cylinder  14  due to the misalignment of the ports  28   a  through  30   b  of the inner cylinder  12  with the ports  42   a  through  44   b  of the outer cylinder  14  and the installation of the plug  24  in the filler port  22 , as shown in  FIG. 2A . 
     At this point the apparatus  10  may be lowered down the borehole by means of the flexible suspension line  62 . The depth of the apparatus  10  is determined according to the length of the line  62  paid out, to position the apparatus  10  at the predetermined depth desired. A secondary weight  64  may be removably attached to the bottom of the inner cylinder  12  to depend therefrom, e.g., by a length of cord or other line  66  passed through a transverse hole in the plug  24 , or other attachment means as desired. The secondary weight  64  is optional, as indicated by its illustration in broken lines in  FIGS. 2A and 2B . The secondary weight  64  serves to increase the total density of the apparatus  10  and attached weight  64  when the apparatus is used in a well or borehole containing a relatively dense liquid, and/or to increase the rate of descent through a fluid in the borehole. 
     At this point the apparatus  10  is positioned at the desired predetermined depth in the borehole or well, with the tracer agent or other material still sealed within the inner cylinder  12 . The tracer agent is released by a weight  68  that is disposed concentrically along the suspension line  62 . While the weight  68  is illustrated as a frustoconical solid in the drawings, the shape or configuration of the weight  68  is not critical so long as it possesses sufficient mass to actuate the apparatus  10  as described below. Larger and/or more streamlined weights may be incorporated, as desired. 
     The weight  68  remains at the surface as the apparatus  10  is lowered into the borehole or well. Once the apparatus  10  is positioned at the desired depth, the weight  68  is dropped and it slides down the line  62 . When the weight  68  strikes the top wall  34  of the outer cylinder  14 , it jars or displaces the outer cylinder  14  downward around the inner cylinder  12 , which cannot move vertically due to its attachment to the suspension line  62 . The outer cylinder  14  is displaced downward by the force of the weight  68  until its top wall  34  strikes the upper edge of the top extension  18  of the inner cylinder  12 . This configuration also results in the various ports  42   a  through  44   b  of the outer cylinder  14  aligning with the corresponding ports  28   a  through  30   b  of the inner cylinder  12 , generally as shown in  FIG. 2B , to release the tracer agent contained within the inner cylinder  12 . Once the tracer agent has been released from its container  32  within the inner cylinder  12 , the apparatus  10  may be lifted back to the surface by means of the flexible line  62  and reconfigured for reuse as desired. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.