Abstract:
Apparatus and method for boring into the earth near a Kudzu vine root system to apply herbicidal helium gas to the roots and eradicate the Kudzu vine. The technique uses a perforated tube with a drill bit that protrudes from one end of the tube to bore into the earth near the vine roots. Boring is stopped when all of the tube perforations are below the earth&#39;s surface. About 0.5 cubic meters of helium gas are applied to flow through the tube enabling the helium gas to flow out through the tube perforations and attack the Kudzu vine through the vine&#39;s root system.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to method and apparatus for destroying Kudzu vines ( pueraria lobata ) and, more particularly, to the application of helium gas to Kudzu vine root systems through a perforated tube driven into the soil close to the vine&#39;s roots, and the like. 
     DESCRIPTION OF THE PRIOR ART 
     Clearly, there is a need to eradicate, or at least to control the rampant growth of the Kudzu vine in southeastern United States. Illustratively, this plant grows very swiftly—as much as sixty feet in one year, thereby not only choking and depriving the surrounding trees and plant life of moisture and nutrients, but also promoting forest fires. 
     Because this vine grows in proximity to other more desirable plant life an herbicide to be effective in controlling or eradicating the Kudzu vine must be specific to the Kudzu plant and must not destroy surrounding plant growth. The direct application of helium, as a gas, to Kudzu root systems was found to have the potential to destroy this weed selectively in the presence of profuse plant growth without adversely affecting other nearby plants. 
     There are at least two theories extant that attempt to explain the herbicidal effect that helium gas has on the Kudzu vine. For example, one theory hypothesizes that chemically inert helium, concentrating in the plant, forms an embolism that obstructs the flow of water and nutrients within the vine. Another theory proposes that chemically inert helium acts as a possible carrier molecule, also with an herbicidal effect on the Kudzu vine. 
     In these circumstances with a great deal of effort it has been ascertained that helium is the herbicidal agent of choice for the Kudzu vine. And, on establishing helium as a specific Kudzu herbicide it is then necessary to develop a suitable apparatus for applying helium to the vine in a lethal concentration. 
     In the past, a ditch had been excavated and a perforated vinyl pipe horizontally disposed in the ditch to discharge the helium near a Kudzu vine root system. The pipe then was coupled to large helium tanks on the earth&#39;s surface. This technique is expensive and cumbersome in that it requires excavation equipment and frequently involves the burden of carrying heavy tanks of helium into densely overgrown woods. 
     To provide a truly acceptable device for applying the helium gas herbicide to a Kudzu vine, a number of important criteria must be satisfied. For instance the device must be lightweight, sturdy and easy to use. Further in this connection, the structure must be proof not only against corrosion, but also strong enough to drill through soil while coping with rocks and stones without bending or otherwise deforming. The length of the device, moreover, must be adequate to reach deep Kudzu roots. 
     Thus, there continues to be a need to provide an efficient system for applying helium gas to the Kudzu root structure that is portable, inexpensive and effective in eliminating the Kudzu weed. 
     BRIEF SUMMARY OF THE INVENTION 
     The foregoing need for a suitable herbicidal helium gas delivery system is satisfied to a large extent through the practice of the invention. For example, a tube has a drill bit protruding from one end of the tube. A shank that ordinarily is engaged by a drill&#39;s chuck, protrudes from the opposite end of the tube. 
     A nipple, to establish gas communication between an externally mounted valve and the interior of the tube is attached to the tube and close to the shank end of the tube. Two sets of perforations are formed, each along the length of the tube and on opposite sides of the tube to enable gas within the tube to penetrate the surrounding soil. Each of these sets of perforations, moreover, are spaced below the nipple and valve combination. 
     A power drill is coupled to the shank and is activated to enable the drill bit to bore into the soil near a selected Kudzu vine root. The drill is deactivated on reaching a suitable depth in which at least all of the perforations formed along the length of the tube are well below the earth&#39;s surface. A small canister of helium is coupled through a flexible conduit to the inlet side of the valve and the valve is opened to enable the helium to flow into the tube, through the sets of perforations, and out into the surrounding soil in order to reach the Kudzu vine&#39;s root system. On exhausting the helium content of two canisters, producing in total about one half cubic meter of helium at standard pressure and temperature, the last canister is disconnected from the valve, and the direction of drill rotation is reversed to draw the tube out of the soil in which it is lodged and the tube, on complete withdrawal, is now ready for use elsewhere. 
     For a more detailed appreciation of the invention, reference is made to the following description of a preferred embodiment of the invention when taken with the drawing. The scope of the invention, however, is limited only through the claims appended hereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  of the drawing is a front elevation of an illustrative embodiment of the invention; and 
         FIG. 2  is an enlarged view of the lower portion of the embodiment of the invention shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As illustrated in the drawing, a hollow tube  10  of stainless steel, copper, carbon fiber reinforced plastic or other suitable material, preferably of about 1.8 cm in outside diameter and about 1.6 cm inside diameter is approximately 87 cm in length. A first set  12 A of five gas release perforations  12 ,  13 ,  14 ,  15  and  16 , each of about 0.16 cm in diameter are formed in the tube  10  in alignment with longitudinal tube axis  17 . The perforation  12  is spaced about 38 cm from tube end  20  and each of the subsequent perforations  13 ,  14 ,  15  and  16  are spaced, commencing with the perforation  13  and progressing toward opposite tube end  21  by successive distances of about 7.6 cm, measured each from the next adjoining of the perforations. 
     A set  22 A ( FIG. 2 ) of five gas release perforations (of which only perforations  18  and  22  are shown in the drawing) are similar to the first set  12 A of the perforations  12  through  16 . The set  22 A, however, is formed on the side of the tube  10 , that is opposite to the side of the tube  10  occupied by the perforation set  12 A. The perforations in the second set  22 A, also are in alignment with the longitudinal tube axis  17  but are staggered relative to the spacing for the first set  12 A of the perforations  12  through  16 . Thus, the gas release perforation  22  in the second set  22 A is spaced 3.8 cm from the perforation  15  and 3.8 cm from the next adjacent perforation  16  in the first perforation set  12 A. 
     The tube end  20  ( FIG. 1 ) has a shank  23  that is welded or otherwise appropriately secured in hollow center  24  ( FIG. 2 ) of the tube  10 . As shown, the shank  23  is designed for engagement by a chuck (not shown) for a battery powered drill (also not shown). A sears “Craftsman” hand impact drill, identified through product number 11581, has been satisfactory for use in accordance with the invention. 
     To establish fluid communication with the hollow center  24  ( FIG. 2 ) of the tube  10 , a nipple  25  ( FIG. 1 ) is brazed, or otherwise joined to a matching opening (not shown in the drawing) in the surface of the tube  10 . For the purpose of the invention, a galvanized steel screw nipple is preferred for this use. A threaded end  26  protrudes from the nipple  25  to engage a corresponding female thread in valve outlet  27  to establish a gas-tight connection with a valve  28 . 
     It has been found that a 0.6 cm inside diameter brass ball valve, manufactured by Mueller/B&amp;K and identified through product number 107-701 has been suitable for helium gas flow control in accordance with the invention as described subsequently. Inlet  30  for the valve  28 , moreover, has a gas adapter  31  with a surface that is serrated in order to make a gas tight connection between the valve  28  and one end of a flexible clear vinyl conduit  32 . In turn, the other end of the conduit  32  establishes gas communication with a small, portable helium canister  33 . 
     With respect to the helium canister  33 , two canisters, each having 0.25 cubic meters of helium gas under a pressure (when full) of at least 260 pounds per square inch (PSI), for a total of 0.5 cubic meters at standard atmospheric pressure and temperature provide a suitable herbicidal effect when the canister  33  (only one of which canisters is shown in the drawing) are applied in sequence in accordance with the invention. Further in this connection, helium canisters sold by Balloon Time under product number SKU 114710 with a helium purity of 94% to 96% were used with the method and apparatus described herein and have produced the desired Kudzu vine herbicidal result. Naturally, for Kudzu eradication over larger areas, large helium tanks also have been used with great success. 
     In operation, the chuck on a battery powered drill (not shown in the drawing) connects the drill to the drill shank  23 . The tube  10  is placed near a Kudzu vine stem as that stem protrudes above the earth with the longitudinal tube axis  17  of the tube  10  generally perpendicular to the surface of earth  35  to press drill bit  11  against the soil. Preferably a 1.6 cm diameter black oxide coated drill bit is suitable for this purpose. 
     The drill is energized and the torque applied by the drill turns the tube  10  and the drill bit  11 , causing the drill bit  11  and the balance of the tube  10  to bore into the earth. The drilling is continued until all of the perforations in the two perforation sets  12 A and  22 A are well below the surface of the earth, whereupon the drill is deactivated and disconnected from the shank  23 . 
     A first of the two helium canisters  33  is then coupled through the flexible conduit  32  and the gas adapter  31  to the valve  28 . Valve handle  34  is shifted to a valve open position and helium gas flows from the canister  33 , through the valve  28  and into the hollow center  24  ( FIG. 2 ) of the tube  10 . 
     Once in the tube  10 , under the gas pressure supplied by the helium canister  33 , the helium gas disperses into soil  36  surrounding the tube  10  through the perforations in the sets  12 A and  22 A and migrates in the soil  36  to Kudzu vine root  37 . Upon depletion of the helium in the canister  33 , the valve handle  34  is shifted to close the valve  28 . With the valve  28  closed, the helium canister  33  is removed and replaced with a fresh, full helium canister, whereupon the process practiced with the first canister  33  is repeated until the helium in the second canister also is depleted. 
     Field trials have shown that four weeks after exposure to helium in the manner described above, in two test sites all of the Kudzu vines so treated were destroyed. At a third test site an estimated 95% of the Kudzu was destroyed. The effect, moreover, of this Kudzu vine treatment on surrounding plant life was found to be surprisingly beneficial, as observed not only through the growth of new grass but also through new leaf growth. 
     After treatment, the second, depleted canister and the associated flexible conduit  32  are detached from the gas adapter  31 . The drill is reconnected to the shank  23  and the drill is reenergized, albeit with the torque reversed, to enable the tube and the bit to be withdrawn from the ground. When treatment is complete and the tube  10  and the associated drill bit  11  have been withdrawn from the earth, the spoil (not shown in the drawing) from the original drilling is used to fill the hole left by the tube and the drill bit. 
     In passing it can be inferred from the accumulated data that other inert gases—argon, neon, krypton and xenon, for instance, might also be commercially acceptable Kudzu vine herbicides.