Abstract:
There is provided by the present invention an injection system for use in injecting a liquid into a tree, the system comprising: (A) a liquid supply assembly ( 10 ) comprising a liquid supply inlet ( 34 ) for providing the liquid to the assembly at ambient pressure, an electric pump ( 68 ) for pressurizing and discharging the liquid from the assembly at a first pressure above ambient pressure through a liquid supply outlet ( 36 ), a pressure switch ( 72 ) connected to the supply outlet and in electrical communication with the pump for selectively actuating the pump when the pressure of the liquid supply outlet falls below said first pressure.

Description:
[0001]    The present disclosure relates generally to injecting liquid into the stem or trunk of a tree, and more particularly, this disclosure relates to injecting liquid such as a pesticides, growth regulators or nutrient and/or fertilizers into the sapwood of a tree trunk. 
         [0002]    Arborists may inject liquids, such as insecticides, fungicides, growth regulators, nutrients and/or fertilizers, into the sapwood of tree trunks in an effort to maintain or improve the health of the trees. For example and in one of the known methods, a borehole is formed into the sapwood, thereafter the outer end of the borehole is closed by fixedly mounting a plug in the outer end of the borehole, and thereafter a needle of an injector is inserted through a septum of the plug so that the tip of the needle projects farther into the borehole than the plug. Then, the injector may discharge liquid into the borehole by way of the portion of the needle that projects farther into the borehole than the plug. The needle may be withdrawn from the plug, and the plug&#39;s septum may seal the plug so that the injected liquid is contained in the inner portion of the borehole until the injected liquid is drawn upwardly in the sapwood of the tree. Alternatively, a needless injector used with a plug having a check valve is employed. In either case, the plug may optionally remain installed in the tree trunk for subsequent treatments by way of the plug. 
         [0003]    For example, published PCT application WO2012114197 entitled “Tree Injection Apparatus and Methods” discloses an injector and an associated liquid supply assembly that includes a T-joint mounted between a barrel, a dosing assembly, a trigger assembly and a manifold assembly from which a supply of formulation for injection is provided from containers once they are pressurized. 
         [0004]    Notwithstanding, the above-described tree injection equipment may be considered to be labor intensive and time consuming, such as when the tree injection formulation is decanted from a bulk product container into the tree injection equipment or potentially less hygienic when such equipment requires the use of pressurized product containers. Accordingly, there is a desire for tree injection system, apparatus and methods that provide a new balance of properties for enhanced tree management. 
       SUMMARY OF THE INVENTION 
       [0005]    The following presents a simplified summary of this disclosure in order to provide a basic understanding of some aspects of this disclosure. This summary is not an extensive overview of the disclosure and is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The purpose of this section is to present some concepts of the disclosure in a simplified form as a prelude to the more detailed description that is presented later. 
         [0006]    There is provided by the present invention an injection system for use in injecting a liquid into a tree, the system comprising: (A) a liquid supply assembly comprising a liquid supply inlet for providing the liquid to the assembly at ambient pressure, an electric pump for pressurizing and discharging the liquid from the assembly at a first pressure above ambient pressure through a liquid supply outlet, a pressure switch connected to the supply outlet and in electrical communication with the pump for selectively actuating the pump when the pressure of the liquid supply outlet falls below said first pressure. 
         [0007]    The inventive system further comprises (B) an injection gun comprising an injector inlet in fluid communication with the liquid supply assembly (A) for receiving the liquid from the liquid supply assembly at said first pressure; an injector outlet for discharging the liquid from the injector assembly; a trigger assembly being in fluid communication with the injector inlet and the injector outlet and movable from a first position to a second position; and (C) a liquid dosage assembly for providing a metered dose of the liquid to the tree. 
         [0008]    Advantageously, the dosage assembly (C) works cooperatively with the liquid supply system (A) and, in particular, with the pressure switch that is associated with the liquid supply system. The dosage assembly (C) comprises a first chamber for alternately being in fluid communication with the injector inlet and the injector outlet; and a second chamber that contains a gas under a second pressure above ambient pressure which is lower than said first pressure when the system is in operation. The second chamber is cooperatively associated with the first chamber such that it biases the first chamber via a piston or diaphragm arrangement when the trigger is moved from a first position, where the first chamber is in fluid communication with the injector inlet, to a second position where the first chamber is in fluid communication with the injector outlet. During operation, the respective volumes of the first and second chambers change in inverse proportion to one another both when the liquid in the first chamber is discharged through the injector outlet and also when the first chamber is re-filled with liquid received from the liquid supply assembly via the injector inlet. In this regard, the first chamber is for alternately receiving the a metered dose of the liquid from the injector inlet at said first pressure when the trigger is in the first position, and providing the metered dose of the liquid to the outlet at said second pressure when the trigger is in said second position. 
         [0009]    Once triggered, a metered dose is injected into to the tree through the discharge nozzle at the tip of the injection gun when it is engaged with an appropriate borehole having an optional plug. A subsequent metered dose is received in to gun from the liquid supply system when the trigger returns to a starting position when a pressure differential is detected by the pressure switch and thereby selectively actuating the pump to retrieve liquid from an unpressurized supply container. The inventive system can be used with any number of known injection protocols such as, for example, those disclosed in published PCT applications WO/2012/114197 or WO/2013/149993 which are incorporated by reference herein. Suitable protocols can be those which use an injection gun with or without an injection needle and/or with or without the use of an injection plug. The appropriate protocol will depend upon various factors including the nozzle tip, the tree species, the target (insect, nematode, disease, abiotic stress, etc.), the injection liquid components and/or viscosity, the dose volume required and the injection pressure. After an injection is made, the trigger mechanism is reset to a base “untriggered” position and the pressure switch in the liquid supply assembly actuates the pump until the first chamber of the dosage assembly is refilled and ready for a subsequent injection. 
         [0010]    A particular advantage of the inventive system is that the liquid to be injected can be provided by a standard, unpressurized product container. This reduces the chance for unwanted equipment leakage during use and attendant hygiene issues while also avoiding the need to maintain a pressurized bottle or container. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings wherein: 
           [0012]      FIG. 1  is a perspective view of a first side of a liquid supply assembly in accordance with one embodiment of the invention; 
           [0013]      FIG. 2  is a perspective view of the liquid supply assembly shown in  FIG. 1  with the product container removed from the liquid supply manifold; 
           [0014]      FIG. 3  is a perspective view of a second side of a liquid supply assembly in accordance with one embodiment of the invention; 
           [0015]      FIG. 4 a    is a front plan view of the liquid supply assembly shown in  FIG. 1 ; 
           [0016]      FIG. 4 b    is a side plan view of an injection gun assembly in accordance with one embodiment of the invention; 
           [0017]      FIG. 5  is a schematic view of a liquid supply assembly in accordance with one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Certain exemplary embodiments of this disclosure are described below and illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention, which, of course, is limited only by the claims below. Other embodiments of the invention, and certain modifications and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, modifications, and improvements are within the scope of the present invention. 
         [0019]    An example of a tree injection system of the present invention is described in the following, at least initially with reference to  FIGS. 1-3 , in accordance with a first embodiment of this disclosure. A liquid supply system  10  includes a housing enclosure formed by side walls  12   a - 12   d , a base including a stabilizer  14  and a top portion including a manifold cover  26  and the various control components  28 ,  30  and  32 . The enclosure may contain various components of the liquid supply system as shown in  FIG. 5  including, among others, the pump  68 , motor  70 , battery  74 , pressure switch  72  and recirculation valve  78 . 
         [0020]    In the exemplified embodiment, a liquid container  20  such as a product bottle that contains a liquid product to be injected  62  ( FIG. 5 ) is removably attached to the liquid supply system by removing the bottle lid (not shown) and then inserting the liquid supply inlet  34  into the top of the bottle  20  by positioning it on base  14  below the manifold  24 . For example, the liquid product may be one or more of insecticides, nematacides, fungicides, growth regulators, fertilizers, nutrients and/or other liquids that are suitable for being injected into trees. After it is properly positioned, the bottle  20  is then moved upward in the direction of arrow  35  through the bottle cage  18   a - 18   b  to engage with the screw top  22  which is affixed to the bottom of manifold  24 . The liquid supply inlet  34  and liquid recirculation/vent pipe  66  pass through manifold  24  to provide fluid communication with the pump  68  and bottle  20 , respectively, at ambient pressure. The bracket  16  is closed after the bottle  20  is attached to the screw top  20  after which the tree injection system may be initiated. 
         [0021]    Turning now to  FIGS. 4 a -4 b   , to initiate the system, if not already completed earlier, the dosing chamber  50  is calibrated to receive an appropriate injection dose of the selected liquid  62  (typically below 10 ml) and then a hand air pump (not shown) may be attached to the air supply valve  52  to pressurize the air chamber  48  of the dosing assembly  46  to an injection pressure appropriate to selected injection protocol, for example, typically between 2 to 4 bars. The appropriate injection pressure will depend on the protocol and/or tree species to be interrogated by the injection system. The power switch  32  is then placed in to the on position (while making sure that the emergency cut-off switch  30  is in the off position) in order to energize the pump motor  70  and start the pump  68 . The recirculation valve  78  is then opened with switch  28  (for example, for 4-5 sec) in order to charge the pump  68 , i.e., until the portion of the product tube  36  within the housing is filled with liquid  62 . The ambient pressure of headspace  64  during recirculation or normal operation is maintained by back pressure vent  80 . In the exemplified embodiment, opening the valve  78  pumps liquid from the product bottle  20  and recirculates it back to the bottle  20  via recirculation pipe  66 ). The pressure switch  72  is pre-set to a pressure above the pressure of air chamber  48  so that, once the recirculation valve  78  is closed, the liquid  62  is pumped out the port  38  through tube  36  to the gun  40  via inlet  41  into the dosing chamber  50  while the trigger  56  remains in the first upward position (as shown). The dosing chamber  50  is in fluid communication with the liquid supply system  10  while the trigger  56  is in such upward position. The pressure switch  72  and dosing chamber  50  are cooperatively associated so that the pump  68  remains actuated until the dosing chamber  50  is filled. For example, the pressure switch  72  can be set to turn off the pump  68  once the liquid pressure in the system downstream of the pump  68  reaches a value that is both higher than pressure in the air chamber  48  and also indicative of a condition where the dosing chamber  50  is filled with the injection liquid  62 . This can be a setting of from 5 to 7 bars, for example. Meanwhile, the pressure upstream of the pump  68  including the supply inlet  34  and the product bottle headspace  64  remain at ambient pressure. 
         [0022]    Once the dosing chamber  50  is filled, an operator such as an arborist can take the gun  40  via palm grip  58  and handle  60  and engage the injection gun outlet  45  to a target tree via an appropriate borehole or opening. As noted above, the injection system of the invention can be used with injection protocols known in the art and the outlet  45  can be configured to accommodate a needle, to be used in needleless protocols, to set plugs, or the like, as dictated by the tree injection protocol being employed by the arborist/operator. Once the gun outlet  45  is engaged with a tree injection site, the operator will move the trigger  56  down to a second position (not shown) toward T-joint  42  of the main body of gun  40 . This second trigger position closes the fluid communication of the dosing chamber  50  to the liquid supply system  10  and opens the fluid communication of the dosing chamber  50  to the gun outlet  45  via barrel  44 . Once this occurs, the piston  54  is moved by the pressure in air chamber  48  (which is above ambient pressure) which pressure discharges the liquid from dosing chamber  50  through the gun outlet  45  at such pressure. 
         [0023]    After the injection is complete the trigger  56  is released to return to the first position (for example, via a spring mechanism or the like) and the empty dosing chamber  50  is again in fluid communication with the liquid supply assembly  10 . The function of the trigger can, of course, be achieved by other activation means such as switches, buttons or remotely as known to those skilled in the art. At this point, the liquid pressure in the system downstream of the pump  68  is provided by the pressure in air chamber  48 . In accordance with an embodiment of the invention, as the pressure in air chamber  48  is lower that the value selected for the pressure switch  72 , the switch  72  actuates the pump  68  until the pressure returns to a pre-set value above ambient pressure that also corresponds to a pressure where the dosing chamber  50  is in a filled condition. Accordingly, use of the injection system of the invention requires significantly less time to inject multiple trees and/or trees with multiple injection sites as the dosing chamber can be emptied and filled quickly and automatically in rapid succession until the product bottle  20  is emptied or until the battery  74  is discharged. A discharged battery  74  can be recharged from a fixed or mobile power source via charging jack  76 . Moreover, empty product bottles  20  can be quickly replaced with a filled bottle  20  without turning off the system as the bottle and manifold  24  remain at ambient pressure. The tree injection system of the invention also avoids the need for decanting liquid product and for use of pressurized product bottles which improves operator safety and hygiene. 
         [0024]    In the event of unforeseen circumstances, as shown in the exemplified embodiment, the system can be reset by pushing down on the switch cap  30   a  of the emergency cut-off switch  30 . The cut-off switch  30  activates both the emergency electric switch  82  which turns off the pump motor  70  and also opens the recirculation valve  78 . In the exemplified embodiment, the recirculation valve is opened when the switch cap  30   a  engages with lip  28   a  of the recirculation valve switch  28 . Once this occurs, the downstream system pressure is provided by the air chamber  48  of the dosing assembly  46  which recirculates much of the liquid present in the gun  40  and line  36  back to the product bottle  20 . 
         [0025]    By way of summary, the schematic of  FIG. 5  discloses a product container  20  maintained at ambient pressure that contains tree injection liquid  62  which is pumped by pump  68  from liquid supply line  34  via supply tube  36  to the tree injection gun jet  40  at a selected pressure above ambient pressure and above the pressure in the air chamber  48  (which is also set above ambient pressure). During operation of the pump  68 , the headspace  64  of bottle  20  is maintained at ambient pressure (sometimes via operation of valve  80  and vent pipe  66 ) as liquid  62  is pumped from the bottle  20  and discharged through outlet  36  at a pressure above ambient pressure. The pump  68  is suitably a membrane pump that is selectively activated after the gun jet  40  is triggered to release liquid from the dosing chamber  46 , guided by a pressure valve  72  which stops the pump when the line pressure reaches a pre-set limit (e.g., 4-7 bars, more particularly 5-7 bars, or from 5 to 6 bars); suitably, the limit is selected to correspond with the dosing chamber  48  being in a filled condition. In one embodiment, the pump and other electric components are energized by a battery  74 . After operation, the main power switch  32  is switched off. To clean the system, the product bottle  20  can be replaced with a water bottle and the system is turned on. The tubes  34 / 36  and the injection gun  40  can be rinsed by several discharges of water through the injection gun  40 . Suitably, the discharged rinsing water is to be collected in a marked waste bottle for appropriate disposal. 
         [0026]    Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.