Patent Publication Number: US-8113279-B2

Title: Apparatus and method for instantaneously injecting tracer for groundwater well

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2009-0012017, filed on Feb. 13, 2009, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method for sequentially performing instantaneous injection of a tracer by changing a depth within a groundwater observation well. 
     2. Description of the Related Art 
     A tracer test is a method to know the properties of hydraulic connectivity and hydraulic dispersion of a medium through the reaction morphology to a chemical impact which is in higher concentration than a background concentration. Steps of selecting a tracer, making a solution, injecting the tracer and observing/analyzing concentration change are performed to complete a tracer test. The point dilution technique is a kind of the trace test. It aims to relate the observed dilution of a tracer, introduced into a groundwater observation well, to groundwater flow. 
     Generally, a point dilution test is carried out after a specific section within a well is isolated by a packer and a tracer is injected into the section between the upper packer and the lower packer through a tracer injection pipe. The packer installed in the specific section in the well aims to prevent a vertical flow of groundwater in the specific section. 
     However, when the packer is used, a lot of equipment is increasingly needed to perform the tracer test and a lot of time and work are needed to move/install/disjoint the packer in the well. In the case where there is no vertical flow of the groundwater in the well or the vertical flow is insignificant, it is possible to perform the tracer test by injecting the tracer without installing the packer. However, in this case, since it is difficult to continue carrying the tracer, the tracer test is limited to one. 
     SUMMARY OF THE INVENTION 
     The present invention is to develop a technique capable of sequentially supplying a tracer to a container of an apparatus for injecting the tracer and instantaneously injecting the supplied tracer to a specific depth in a well. For this purpose, it is an object of the present invention to provide an apparatus which is capable of supplying a tracer to a container of an apparatus for injecting the tracer, instantaneously injecting the tracer by controlling opening and closing of the container, and repeatedly performing these processes. The development of this apparatus has the advantage of making it possible to sequentially perform a tracer test by moving test equipment to a different depth within the well, without pulling up the test equipment after the tracer test is performed at a specific depth in the well. Therefore, time and work required for the tracer test are minimized. 
     The above and other objects and advantages of the present invention will be described below and become more apparent by describing in detail exemplary embodiments. The objects and advantages of the present invention are realized by the means disclosed in the claims and by the combination of the means. 
     According to an aspect of the present invention, there is provided an apparatus for instantaneously injecting a tracer to a specific depth in a groundwater observation well, comprising: a bi-directional piston with one end receiving a piston shaft moving up/down; an upper plate connected to a lower end of the bi-directional piston; a lower plate spaced apart from the upper plate at a predetermined distance to form a space and connected to the upper plate through a number of connection rods; a container with one end fixedly connected to the piston shaft within the space and the other end being opened and hollow; a tracer injection rod fixedly installed at the lower plate in a perpendicular direction to be operatively connected each other, and having one end forming a piston inserted into the other end of the container; and a tracer injection pipe with both of upper and lower ends being opened, the upper end fixed to the upper plate and the lower end operatively connected to the lower plate. 
     Further, the container comprises a number of guide rings formed to protrude from an outer circumferential surface of the container, to receive a number of the connection rods and to guide the container in a movement direction upon moving up/down. 
     Further, the apparatus comprises a tracer tank for storing the tracer; an injection line with one end operatively connected to the tracer tank and the other end operatively connected to the tracer injection pipe; and a driving pump installed in the middle of the injection line, to pressurized the tracer to the tracer injection pipe so that the tracer is supplied to the tracer injection pipe. 
     Further, the tracer injection rod is hollow and comprises a number of release openings formed by boring on an outer circumferential surface of the tracer injection rod, so that the tracer supplied to the tracer injection pipe is released through the release openings. 
     Further, when the piston shaft is moved down by the bi-directional piston, the container receives the whole of the tracer injection rod lengthwise and the other opened end of the container is closely secured to the lower plate, and when the piston shaft is moved up by the bi-directional piston, the container moves up together with the piston shaft so that only the piston of the tracer injection rod is received in the other opened end of the container. 
     Further, the lower plate comprises a connection groove formed on the top of the lower plate to correspond and fit with the other opened end of the container; and a packing ring inserted in the connection groove, to maintain an airtight state at a connection region when the container moves down to be fitted into the connection groove. 
     Further, the piston comprises an operative connection opening formed by boring and the container comprises an outlet opening formed on the top of the container, so that the pressure inside and outside the container is equally/consistently maintained even after the tracer is injected. 
     Further, the apparatus comprises: a sensor attached to the outer circumferential surface of the tracer injection rod lengthwise, to check the concentration of the tracer released around the tracer injection rod so as to be compared with the initial concentration of the tracer being injected. 
     Further, the bi-directional piston comprises a fixing ring on its top so that a fixing wire is connected to the fixing ring, and the fixing wire is controlled by a winch installed on a ground so that the apparatus is moved down to a desired target depth to be measured within an groundwater observation well. 
     Further, the bi-directional piston has an upper end connected to one end of a first supply line and the lower end connected to one end of a second supply line, and the other ends of the first and second supply lines are connected to a pneumatic supply tank installed on the ground. 
     Further, each of the upper and lower plates comprises a number of plates, auxiliary members are connected between a number of the upper plates and between a number of the lower plates, respectively, wherein the auxiliary member has a relatively greater diameter than those of the upper and lower plates and a number of the auxiliary members are face-joined in one body and include a number of cut parts formed at the equal intervals, along the circumference. 
     According to another aspect of the present invention, there is provided a method for instantaneously injecting a tracer for a groundwater well, comprising: step (S 100 ) of dropping an apparatus for instantaneously injecting the tracer for the groundwater well to an operator&#39;s desired depth to be measured within an groundwater observation well; step (S 200 ) of moving down a container to receive the whole of a tracer injection rod by supplying pressure to a first supply line of a bi-directional piston; step (S 300 ) of filling the tracer in the container by supplying the tracer to a tracer injection pipe and releasing the supplied tracer through an release opening of the tracer injection rod; step (S 400 ) of releasing the tracer outside by moving up the container by supplying the pressure to a second supply line of the bi-directional piston; step (S 500 ) of checking, for a predetermined time, the concentration of the released tracer, using a sensor positioned on an outer circumferential surface of the tracer injection rod; and step (S 600 ) of determining whether to repeat measurement at the same depth within the groundwater observation well or to re-start measurement by changing a depth. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a front view of an apparatus for injecting a tracer being applied according to an exemplary embodiment of the present invention; 
         FIG. 2  is a front perspective view of the apparatus of  FIG. 1  before and after a container moves up/down; 
         FIG. 3  is a perspective view to explain an operation of the apparatus of  FIG. 1  before it is dropped to a target depth; 
         FIG. 4  is a perspective view to explain a step of moving down the container after the apparatus of  FIG. 1  is dropped to the target depth; 
         FIG. 5  is a perspective view to explain a step of supplying a tracer into the container; 
         FIG. 6  is a perspective view to explain a step of releasing the tracer around the target depth by moving up the container; 
         FIG. 7  is a perspective view to explain a tracer injection rod; 
         FIG. 8  is a perspective view to explain a step of measuring the concentration of the tracer released by the apparatus of  FIG. 1 ; and 
         FIG. 9  is a flow chart of a method for injecting a tracer using the apparatus of  FIG. 1 . 
     
    
    
     BRIEF DESCRIPTION OF REFERENCE NUMBERS OF MAJOR ELEMENTS 
     
       
         
           
               
               
               
               
             
               
                   
               
             
            
               
                 10: 
                 bi-directional piston 
                 11: 
                 piston shaft 
               
               
                 12: 
                 first inlet opening 
                 13: 
                 second inlet opening 
               
               
                 14: 
                 fixing ring 
                 20: 
                 upper plate 
               
               
                 21: 
                 through-aperture 
                 22: 
                 connection rod 
               
               
                 23: 
                 space 
                 24: 
                 auxiliary member 
               
               
                 25: 
                 cutting part 
                 30: 
                 lower plate 
               
               
                 31: 
                 connection groove 
                 32: 
                 packing ring 
               
               
                 40: 
                 container 
                 41: 
                 guide ring 
               
               
                 42: 
                 outlet opening 
                 50: 
                 tracer injection rod 
               
               
                 51: 
                 piston 
                 52: 
                 release opening 
               
               
                 53: 
                 operative connection opening 
                 60: 
                 tracer injection pipe 
               
               
                 70: 
                 sensor 
                 80: 
                 tracer tank 
               
               
                 81: 
                 driving pump 
                 82: 
                 injection line 
               
               
                 90: 
                 winch 
                 91: 
                 fixing wire 
               
               
                 100: 
                 pneumatic supply tank 
                 101: 
                 first supply line 
               
               
                 102: 
                 second supply line 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION OF THE INVENTION 
     Before exemplary embodiments of the present invention are described in detail, it will be understood that, detailed constitution and arrangements of elements described in the detailed description or illustrated in the drawings should not be construed as limiting the application of the invention. The invention may be embodied in many alternate forms and performed in various methods. The terms or words to describe the direction of an apparatus or element (for example, “front”, “back”, “up”, “down”, “top”, “bottom”, “left”, “right” and “lateral”, among others) are used to simplify the description of the invention. It will be, therefore, understood that these terms do not mean that the relevant apparatus or element shall be only in the specific direction. 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. It will be understood that words or terms used in the specification and claims shall not be interpreted as the meaning defined in commonly used dictionaries. It will be further understood that the words or terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the technical idea of the invention, based on the principle that an inventor may properly define the meaning of the words or terms to best explain the invention. 
     Accordingly, while example embodiments of the present invention are capable of various modifications and alternative forms, embodiments of the present invention are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments of the invention to the particular forms disclosed, but on the contrary, example embodiments of the invention are to cover all modifications, equivalents, and alternatives falling within the scope of the invention. It will be also understood that, the terms, such as “first” or “second”, are used for clarification in the detailed description and claims and therefore, the terms should not be construed as indicating any relative importance, intent or meaning. 
     As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     An apparatus and method for instantaneously injecting a tracer for a groundwater well according to an exemplary embodiment of the present invention will be described, in detail, with reference to  FIGS. 1 through 9 . 
     As illustrated, the apparatus for instantaneously injecting a tracer for a groundwater well according to the present invention comprises: a bi-directional piston  10 , an upper plate  20 , a lower plate  30 , a container  40 , a tracer injection rod  50  and a tracer injection pipe  60 . 
     The bi-directional piston  10  includes a piston shaft  11 . The piston shaft  11  includes one end installed at an inner bottom of the bi-directional piston  10  and moves bi-directionally, up and down. The other end of the piston shaft  11 , the one end of which is installed at the inner bottom of the bi-directional piston  10 , is fixedly connected to the container  40 . A first inlet opening  12  and a second inlet opening  13  through which pressure is injected are each formed on an upper end and a lower end of an outer circumferential surface of the bi-directional piston  10 . A fixing ring  14  connecting a fixing wire  91  is formed on the top of the bi-directional piston  10 . The fixing wire  91  is movable up and down by a winch  90  installed on the ground G, to position an apparatus  110  for injecting a tracer within a groundwater observation well H. 
     The first inlet opening  12  formed at the upper position is connected to one end of a first supply line  101 , and the second inlet opening  13  formed at the lower position is connected to one end of a second supply line  102 . The other end of each of the first and second supply lines  101  and  102  is connected to a pneumatic supply tank  100  installed on the ground G, to receive the pressure supplied from the pneumatic supply tank  100 . 
     That is, when the pressure is supplied to an upper part of the bi-directional piston  10  through the first inlet opening  12 , the piston shaft  11  with one end installed at the inner bottom of the bi-directional piston  10  is moved down. When the pressure is supplied to a lower part of the bi-directional piston  10  through the second inlet opening  13 , the piston shaft  11  is moved up. 
     The upper plate  20  is installed at the bottom of the bi-directional piston  10 . The upper plate  20  includes a through-aperture  21  to receive the piston shaft  11  with the one end installed at the inner bottom of the bi-directional piston  10 . 
     A number of the upper plates  20  are positioned at the upper position so as to be face-joined, and a number of the lower plates  30  (to be described later) are positioned at the lower position so as to be face-joined. 
     An auxiliary member  24  is connected between the adjacent upper plates  20 . The auxiliary member  24  has a relatively greater diameter than that of the upper plate  20 . The auxiliary member  24  is formed of a number of cutting parts  25  which are cut at the equal distance, along the circumference. The cutting parts  25  are cut to a predetermined length from an outer circumference toward the centre. A number of the auxiliary members  24  are connected one another so as to be in one body. The cutting parts  25  formed in each auxiliary member  24  are cut at different positions so as not to be operatively connected one another. 
     The auxiliary members  24  are connected to a plurality of the upper plates  20  and to a plurality of the lower plates  30 . When the apparatus for injecting a tracer is moved down within the groundwater observation well H and is positioned at a desired depth, the auxiliary members  24  minimize upward/downward flows of groundwater, to seal a space between the upper plates  20  and the lower plates  30  so that a tracer released between the upper plates  20  and the lower plates  30  may not be influenced by the groundwater flowing in a vertical direction. Further, the auxiliary members  24  come into contact with a wall of the groundwater observation well H, to make the apparatus for injecting a tracer so as to be positioned at the centre of the groundwater observation well H. The each cutting part  25  formed in a number of the auxiliary members  24  in accordance with the diameter of the groundwater observation well H is bent selectively upward or downward, to come into contact with an inner circumference of the groundwater observation well H. 
     Further, the auxiliary members  24  which are face-joined to be in one body are cut at different positions so that the cutting parts  25  formed in the auxiliary members  24  should not be operatively connected one another, to prevent the groundwater from flowing upward/downward through the cutting parts  25 . The cutting parts  25  are cut to the predetermined length from the circumference of the auxiliary members  24  toward the centre thereof. That is, the cutting parts  25  are cut from the circumference of the auxiliary members  24  within a length so as not to be in contact with the upper plates  20 /the lower plates  30 , thereby preventing the uncut portions of the auxiliary members  24  in contact with the upper plates  20 /the lower plates  30  from being easily broken. 
     The lower plate  30  is positioned under the upper plate  20 . The lower plate  30  is connected to the upper plate  20  by a number of connection rods  22  each having a predetermined length. Accordingly, a space  23  is formed between the upper plate  20  and the lower plate  30 . The piston shaft  11  and the container  40  (to be described later) connected to the piston shaft  11  move up/down within the space  23 . 
     The lower plate  30  is hollow to be operatively connected to the tracer injection rod  50 . 
     A connection groove  31  in a ring shape is formed on the top of the lower plate  30 . The connection groove  31  contacts with and fits to the other end of the container  40  (to be described later). A packing ring  32  has a shape corresponding to that of the connection groove  31  and is fixedly inserted into the connection groove  31 . 
     The container  40  is fixedly connected to the other end of the piston shaft  11  moving up/down in a length direction of the bi-directional piston  10 . A number of outlet openings  42  are formed on one end (the top) of the container  40  fixed to the other end of the piston shaft  11 . The outlet openings  42  are operatively connected. The other end of the container  40  is open. The container  40  has a cylindrical shape being hollow. Accordingly, since one end of the container  40  is fixed to the piston shaft  11 , when the pressure is injected into the bi-directional piston  10  and the piston shaft  11  moves up/down, the container  40  moves up/down in the same manner that the piston shaft  11  moves up/down. 
     In other words, the piston shaft  11  and the container  40  are move up/down together within the space  23 . When the container  40  moves down by the pressure supplied to the first inlet opening  12 , the other end of the container  40 , which is open, closely comes into contact with the top of the lower plate  30 . Then, the other end of the container  40  which is open and securely fitted into the connection groove  31  formed on the top of the lower plate  30 , and the airtight state between the connection groove  31  and the other end of the container  40  is maintained by the packing ring  32  positioned within the connection groove  31 . 
     A number of guide rings  41  are formed on the outer circumference surface of the container  40  so as to protrude in the direction corresponding to a number of the connection rods  22 . Accordingly, each of the connection rods  22  is inserted into the guide rings  41 , to guide the container  40  to move up/down in the vertical direction when the piston shaft  11  moves up/down. 
     The tracer injection pipe  60  has both ends being open and is in a pipe shape being hollow. One end of the tracer injection pipe  60  is fixed to the upper plate  20 , and the other end of the tracer injection pipe  60  is connected to the lower plate  30  so as to pass through the lower plate  30 . The one end of the tracer injection pipe  60  fixed to the upper plate  20  is connected to an injection line  82 . The injection line  82  is connected to a tracer tank  80  installed on the ground G. Therefore, the injection line  82  supplies the tracer stored in the tracer tank  80  to the tracer injection rod  50  through the tracer injection pipe  60 . Then, a driving pump  81  is installed on the injection line  82 , so that the tracer is pressurized and supplied by the driving pump  81 . 
     That is, when the tracer is supplied through the tracer injection pipe  60 , the supplied tracer moves to the hollow lower plate  30  and flows to the tracer injection rod  50  (to be described later). 
     The tracer injection rod  50  formed on the centre of the lower plate  30  is extended upward in a perpendicular direction. The tracer injection rod  50  has a pipe shape being hollow. One end of the tracer injection rod  50  connected to the lower plate  30  is open to be operatively connected to the lower plate  30 . A disc shaped piston  51  like the piston shaft  11  is formed on an upper end of the tracer injection rod  50 . The piston  51  has a smaller diameter than the inner diameter of the container  40 , to enter the container  40 . The piston  51  includes an operative connection opening  53  in a small size, so that the pressure inside and outside the container  40  is equal and some of the pressurized and injected tracer is released through the outlet openings  42  and the operative connection opening  53  outside the container, making it easy to inject the tracer into the container  40 . 
     In other words, the tracer injection rod  50  includes the upper end forming the piston  51  and the lower end operatively and fixedly connected to the top of the lower plate  30 . When the container  40  moves up by the piston shaft  11 , the piston  51  of the tracer injection rod  50  is entered, at a predetermined length, in the other opened end of the container  40 . When the container  40  moves down by the piston shaft  11 , the container  40  allows the tracer injection rod  50  forming the piston  51  on its upper end to enter inside lengthwise so that the other opened end of the container  40  is fit into the connection groove  31  of the lower plate  30 . 
     Further, the tracer injection rod  50  includes a number of release openings  52  which are formed by boring and spaced apart at equal intervals, lengthwise. When the container  40  moves down to receive the entire of the tracer injection rod  50 , the tracer supplied form the tracer tank  80  and sequentially passing through the tracer injection pipe  50  and the lower plate  30  flows in the length direction of the tracer injection rod  50  and is released through a number of the release openings  52  bored on the outer circumferential surface of the tracer injection rod  50 , to fill inside the container  40 . 
     Then, the groundwater and some of the tracer injected into the container  40  through a number of the outlet openings  42  bored on the top of the container  40  is released outside the container  40 . When the tracer is sequentially injected into the container  40 , the groundwater inside the container  40  is replaced with the tracer. 
     When the injection of the tracer into the container  40  is completed, it needs to wait for a predetermined time until a solution of the tracer being released outside the container upon the injection of the tracer disappears. Subsequently, when the pressure is supplied through the second inlet opening  13  to move the container  40  up for a moment, the tracer is released around the tracer injection rod  50 . 
     Further, a sensor  70  is fixedly installed about the outer circumference of the tracer injection rod  50  lengthwise, to record a change in concentration of the tracer for a predetermined time when the container  40  moves up and the tracer is released. 
     In other words, when the groundwater flows in a horizontal direction at a depth within the well H where an operator releases the tracer for her/his desired measurement, the tracer not only diffuses by the Brown Movement but also is transferred, along the flow direction of the groundwater. Consequently, the concentration of the tracer being earlier released is low due to the diffusion and advection. When the groundwater does not flow but stays static, the concentration of the tracer is diluted by the diffusion only. Since the diffusion changed concentration by the Brown Movement is very small in size, compared to the advection, it may be ignored. Comparing these factors, the groundwater flow is considered by the advection characteristics of the tracer in the depth within the groundwater observation well H. 
     Below, a method for injecting a tracer, using the apparatus for injecting a tracer having the same constitution and structures according to the preferred embodiment as described above, will be described. 
     1. As illustrated in  FIG. 2  or  FIG. 3 , the winch  90  is controlled to adjust a length of the fixing wire  91 , to descend the apparatus for injecting a tracer at the depth within the groundwater observation well H as the operator wants to measure. At this time, the container  40  is positioned at the upper position of the space  23  so that the top of the container  40  contacts with the bottom of the upper plate  20  (Step S 100 ). 
     2. Following Step S 100 , when the apparatus for injecting a tracer is positioned at the desired depth, as illustrated in  FIG. 4  the pressure is supplied through the first inlet opening  12  so that the piston shaft  11  moves down. As the piston shaft  11  moves down, the container  40  moves down, so that the tracer injection rod  50  enters inside the container  40  lengthwise and the opened lower end of the container  40  is closely fixed to the lower plate  30  (Step S 200 ). 
     3. Following Step S 200 , as illustrated in  FIG. 5 , the tracer is supplied to the injection line  82  through the tracer tank  80 . After the tracer sequentially flows to the tracer injection pipe  60 , the lower plate  30  and the tracer injection rod  50 , it is released through the release openings  52  bored on the outer circumference of the tracer injection rod  50 , to flow around the tracer injection rod  50 , that is, into the container  40 . The existing groundwater and some of the newly introduced tracer solution are discharged through the small operative connection opening  53  formed on the tope of the container  40 , so that the groundwater inside the container  40  is replaced with the tracer solution (Step S 300 ). 
     4. Following Step S 300 , after waiting for a given time until some of the tracer solution discharged outside the container  40  disappears, as illustrated in  FIG. 6  the pressure is supplied to the second inlet opening  13  of the bi-directional piston  10 , so that the piston shaft  11  enters into the bi-directional piston  10  and accordingly the container  40  also moves up instantly by the piston shaft  11  moved up. Then, the tracer filled around the tracer injection rod  50  or in the container  40  is released into the groundwater observation well H (Step S 400 ). 
     5. Following Step S 400 , as illustrated in  FIG. 8 , a change in concentration of the tracer released into the groundwater observation well H is recorded by using the sensor  70  fixedly installed on the outer circumference of the tracer injection rod  50 . 
     As described above, the tracer is released by performing sequentially the steps S 100  through S 500 . Then, when the operator wants to repeat measurement at a particular depth, the steps S 200  to S 500  need to be sequentially performed. When the operator wants to perform measurement at a different depth after completing the measurement at the particular depth, (s)he may move the apparatus for injecting a tracer and repeatedly perform the steps (S 100  through S 500 ) sequentially (S 600 ). 
     As described above, in the apparatus for instantaneously injecting a tracer to a groundwater well according to the present invention, it is possible to sequentially supply the tracer to the container of the apparatus, to instantaneously injecting the supplied tracer to a specific depth within the well and to repeat these processes. Furthermore, it enables to sequentially perform a tracer test at another depth within the groundwater observation well where a user wants to measure without moving the equipment. 
     The present invention is to develop a technique capable of sequentially supplying a tracer to a container of an apparatus for injecting the tracer and instantaneously injecting the supplied tracer to a specific depth in a well. For this purpose, it is an object of the present invention to provide an apparatus which is capable of supplying a tracer to a container of an apparatus for injecting the tracer, instantaneously injecting the tracer by controlling opening and closing of the container, and repeatedly performing these processes. The development of this apparatus has the advantage of making it possible to sequentially perform a tracer test by moving test equipment to a different depth within the well, without pulling up the test equipment after the tracer test is performed at a specific depth in the well. Therefore, time and work required for the tracer test are minimized. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.