Abstract:
An improved dual metering tube systems for use in directing liquid to the row units of an agricultural implement uses metering tubes of different diameters, a pressure sensor to sense the pressure in a trunk line through which liquid is fed to the metering tubes and a controller for operating one or more valves to selectively direct liquid through only a set of small diameter tubes, only a set of large diameter tubes or both the small and large diameter tubes. Each of the small diameter tubes is paired with a respective one of the large diameter tubes and flow connected to a common outlet or nozzle associated with a respective row unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 61/953,320, filed Mar. 14, 2014, under 35 U.S.C. §119(e). 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to equipment for delivering liquid products, such as fertilizers or pesticides, to and discharging the liquid products at individual rows of an agricultural implement such as a planter. 
         [0004]    2. Description of the Related Art 
         [0005]    Planters and other row type agricultural implements are commonly outfitted with liquid dispensing systems for distributing liquid agricultural chemicals, such as liquid fertilizer, to each row unit and dispensing the liquid in close proximity to the row unit. Such liquid dispensing systems typically include a tank for holding the liquid, a pump for pumping liquid from the tank, a plurality of branched distribution lines through which the liquid is distributed to a plurality of nozzles or delivery tubes. The liquid is dispersed out of the nozzle or delivery tube onto the field. 
         [0006]    Precision agriculture techniques sometimes require widely varying amounts of a chemical to be applied in different sections of the same field. For example, the farmer may want to apply 5 gallons per acre (GPA) in one area and apply 35 GPA in another area of the same field. The farmer may also operate at a minimum speed of 4 miles per hour (MPH) in one section, but increase to a maximum speed of 10 MPH in another. This combination of changes in application rate and speed at which the implement traverses the field requires a very large change in liquid flow. 
         [0007]    The ability to measure variations in the amount of liquid delivered is easily accomplished with existing flow meters. Likewise, pumps can be controlled to deliver the total volume of liquid necessary over a very wide range of total product flow. 
         [0008]    However, existing systems are not adequate to divide the total flow for an implement (for example a 24 row, 60 foot wide corn planter) down to 24 equal flows to apply to each row or application point the farmer desires. A basic system currently in use to control flow is an orifice disc with an equal size orifice for each application point. The orifice creates back pressure in the liquid distribution tubes then the pressure created produces equal flow through each equal sized orifice. However, fluid dynamics works such that a four-fold increase in pressure is required to gain a two-fold increase in flow. Given that the maximum total pressure is practically limited to under 100 psi with the components typically used in these systems, the maximum flow difference that can be generated by pressure changes is limited. The typical response has been to limit the range of liquid applied to what one orifice can accomplish. Then the farmer can change each orifice disc to a different size if they needed to change their application rate. This process is messy, time consuming and not practical within a single field. 
         [0009]    There have been improvements on the standard orifice disc. One is to use a spring controlled variable orifice. An example of this type of device is shown in U.S. Pat. No. 7,124,964 to Quy Duc Bui. These devices advertise a wider flow range for a given pressure difference than a standard orifice disc. However, in the field they do not always produce sufficiently equal flows at each row to satisfy the farmer&#39;s needs. 
         [0010]    Another product used to achieve this goal is the fluid flow divider sold by John Blue Company and described in U.S. Pat. No. 6,311,716 of Kent R. Jones assigned to John Blue Company. However, these devices are believed to lose row-to-row accuracy at lower application rates. 
         [0011]    It is also known to use a metering tube to improve upon the traditional orifice disc. This is a tube with a specific inside diameter, that is of a substantial length (four to twelve feet is typical). This provides the same pressure drop function as an orifice to create equal row-to-row distribution. However, due to flow dynamics in a tube versus an orifice, an equal pressure range will produce a greater flow range in the tube versus the orifice disc. This allows the farmer to achieve greater variability in liquid application rates and implement speeds with the metering tube compared to the traditional orifice disc. 
         [0012]    It is also known to use dual metering tube systems comprising two metering tubes of different internal diameter for each row. A manually operated valve is used in such systems to selectively direct the flow through only the first tube or only the second tube or through both the first and second tubes allowing the operator to achieve wider flow rates through the tubing at each row unit. However, the manual setting of the system requires the operator to correctly assess which selection of tubes is appropriate and may require the operator to manually readjust the valves when the desired application rates change. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention comprises an improvement to dual metering tube systems for use in directing liquid to the row units of an agricultural implement which uses metering tubes of different diameters, a pressure sensor to sense the pressure in a trunk line through which liquid is fed to the metering tubes and a controller for operating one or more valves to selectively direct liquid through only a set of small diameter tubes, only a set of large diameter tubes or both the small and large diameter tubes. Each of the small diameter tubes is paired with a respective one of the large diameter tubes and flow connected to a common outlet associated with a respective row unit. 
         [0014]    The one or more valves are advanceable between a low flow state in which liquid is only delivered to the set of small diameter tubes, a medium flow state in which liquid is only delivered to the set of large diameter tubes; or a high flow state in which liquid is delivered to both the small diameter tubes and the large diameter tubes. A controller communicates with the pressure sensor and the one or more valves to control the one or more valves to initially position the one or more valves in the low flow state. When the one or more valves are in the low flow state, if the pressure sensed by the pressure sensor exceeds a maximum set pressure the controller advances the one or more valves to the medium flow state. When the one or more valves are in the medium flow state, if the pressure sensed by the pressure sensor exceeds the maximum set pressure to advance the one or more valves to the high flow state or if the pressure sensed by the pressure sensor falls below a minimum set pressure to advance the one or more valves to the low flow state. Finally, when the one or more valves are in the high flow state, if the pressure sensed by the pressure sensor falls below a minimum set pressure to advance the valves to the medium flow state. 
         [0015]    In one embodiment, the set of small diameter tubes includes at least first and second sets of small diameter tubes and the set of large diameter tubes includes at least first and second sets of large diameter tubes. Separate valves are associated with each set of small diameter tubes and each set of large diameter tubes. The controller communicates with the pressure sensor valves associated with each set of small diameter tubes and with each set of large diameter tubes to initially open only the valves associated with the small diameter tubes. When only the valves associated with the small diameter tubes are open, if the pressure sensed by the pressure sensor exceeds a maximum set pressure, the controller closes the valves associated with the small diameter tubes and opens the valves associated with the large diameter tubes. When only the valves associated with the large diameter tubes are open, if the pressure sensed by the pressure sensor exceeds the maximum set pressure, the controller opens the valves associated with the small diameter tubes while leaving the valves associated with the large diameter tubes open or if the pressure sensed by the pressure sensor falls below a minimum set pressure, the controller opens the valves associated with the small diameter tubes and closes the valves associated with the large diameter tubes. When both the valves associated with the large diameter tubes and the valves associated with the small diameter tubes are open, if the pressure sensed by the pressure sensor falls below a minimum set pressure the controller closes the valves associated with the small diameter tubes while leaving the valves associated with the large diameter tubes open. 
         [0016]    The valves are preferably mounted on a mounting bracket which is mounted centrally or at a single location on the row unit type agricultural implement as opposed to mounting separate valves for each pair of small diameter and large diameter tubes at or near each row unit. The mounting bracket includes the valves associated with the small diameter tubes mounted in a first section or column of the bracket and the valves associated with the large diameter tubes mounted in a second section or column of the bracket. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a partially schematic perspective view of a liquid distribution system configured to distribute liquid agricultural chemicals to each row of a row type agricultural implement including a front perspective view of a manifold and valve assembly used in the liquid distribution system for supplying liquid to each row of an eight row implement with the rows split into two, four row sections. 
           [0018]      FIG. 2  is a view similar to  FIG. 1  showing a rear perspective view of the manifold and valve assembly. 
           [0019]      FIG. 3  is a logic diagram for the operating valves of the liquid distribution system. 
           [0020]      FIG. 4  is a front perspective view of an alternative embodiment of the manifold and valve assembly adapted for supplying liquid to an implement having four sections of multiple rows in each section. 
           [0021]      FIG. 5  is a front elevational view of the manifold and valve assembly as shown in  FIG. 4 . 
           [0022]      FIG. 6  is a rear elevational view of the manifold and valve assembly as shown in  FIG. 4 . 
           [0023]      FIG. 7  is a left side elevational view of the manifold and valve assembly as shown in  FIG. 4   
           [0024]      FIG. 8  is a schematic view of an alternative embodiment of a liquid distribution system for row type agricultural implements. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
         [0026]    Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words “upwardly,” “downwardly,” “rightwardly,” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the embodiment being described and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof and words of a similar import. 
         [0027]    Referring to the drawings in more detail,  FIG. 1  is a partially schematic view of a liquid distribution system  1  for mounting on a row type agricultural implement (not shown). The liquid distribution system  1  includes a tank  3 , pump  4 , main feed line  5 , manifold and valve assembly  6  and liquid distribution lines  7  which are routed to each row or row unit (not shown) of the implement. The system  1  shown in  FIGS. 1 and 2  is adapted for dispensing liquid at or near each row of an agricultural implement having eight rows split into two sections of four. 
         [0028]    The components of the manifold and valve assembly  6  are mounted on a mounting bracket  8  which is configured to be bolted or otherwise secured to the frame of the agricultural implement. The manifold and valve assembly  8  includes a manifold  11  having a manifold trunk  12  and first and second manifold branches  13  and  14  extending from manifold trunk  12 . The first manifold branch  13 , or A branch, has first and second outlet tube connectors  17  and  18  connected thereto and the second manifold branch  14 , or B branch, has third and fourth outlet tube connectors  19  and  20  connected thereto. 
         [0029]    First and second group A distribution lines  21  and  22  for routing liquid to smaller diameter branch lines  23  associated with the first and second row sections are connected to first and second outlet tube connectors  17  and  18  respectively. First group A distribution line  21  branches out into four smaller diameter branch lines  23 - 1 ,  23 - 2 ,  23 - 3  and  23 - 4  (first group A branch lines) and second group A distribution line  22  branches out into four smaller diameter branch lines  23 - 5 ,  23 - 6 ,  23 - 7  and  23 - 8  (second group A branch lines). Similarly, first and second group B distribution lines  26  and  27  are connected to third and fourth outlet tube connectors  19  and  20  respectively. First group B distribution line  26  branches out into four larger diameter branch lines  28 - 1 ,  28 - 2 ,  28 - 3  and  28 - 4  (first group B branch lines) and second group B distribution line  27  branches out into four larger diameter branch lines  28 - 5 ,  28 - 6 ,  28 - 7  and  28 - 8  (second group B branch lines). The internal diameter of each smaller diameter branch line  23 - 1  through  23 - 8  is smaller than the internal diameter of each larger diameter branch line  28 - 1  through  28 - 8 . However, the internal diameter of each group A distribution lines  21  and  22  is preferably the same as the internal diameter of the group B distribution lines  26  and  27  so that the pressure drop through distribution lines  21  and  22  and  26  and  27  are generally the same. 
         [0030]    Each of smaller diameter branch line  23 - 1  through  23 - 8  is paired with a larger diameter branch line  28 - 1  through  28 - 8  and routed to a row or row unit. For example the following branch lines may be paired together and each pair routed to a row unit:  23 - 1  and  28 - 1 ;  23 - 2  and  28 - 2 ;  23 - 3  and  28 - 3 ;  23 - 4  and  28 - 4 ;  23 - 5  and  28 - 5 ;  23 - 6  and  28 - 6 ;  23 - 7  and  28 - 7 ; and  23 - 8  and  28 - 8 . At each row unit, the associated pairs of smaller diameter and larger diameter branch lines are connected to a single nozzle or applicator tube  31  with a Y-connector  33 . Branch lines  23 - 1  and  28 - 1  are connected to applicator tube  31 - 1 ; branch lines  23 - 2  and  28 - 2  are connected to applicator tube  31 - 2 ; branch lines  23 - 3  and  28 - 3  are connected to applicator tube  31 - 3 ; branch lines  23 - 4  and  28 - 4  are connected to applicator tube  31 - 4 ; branch lines  23 - 5  and  28 - 5  are connected to applicator tube  31 - 5 ; branch lines  23 - 6  and  28 - 6  are connected to applicator tube  31 - 6 ; branch lines  23 - 7  and  28 - 7  are connected to applicator tube  31 - 7 ; and branch lines  23 - 8  and  28 - 8  are connected to applicator tube  31 - 8 . 
         [0031]    First and second valves  37  and  38 , or group A valves, are connected to the first manifold branch  13  and control flow of liquid out the first and second outlet tube connectors  17  and  18  respectively and to the first and second group A distribution lines  21  and  22 . Third and fourth valves  39  and  40 , or group B valves, are connected to the second manifold branch  14  and control flow of liquid out the second and third outlet tube connectors  19  and  20  respectively and to the first and second group B distribution lines  26  and  27 . 
         [0032]    A primary rate controller  43 , a pressure controller  44  and a valve controller  45  are used to control the flow of liquid through the liquid distribution lines  7  and out applicator tubes  31 - 1  through  31 - 8  based at least in part on the flow rate of the liquid in the main feed line  5  sensed by flow meter  46  and the pressure of the liquid in the main feed line  5  sensed by pressure sensor  47 . In the embodiment shown, flow meter  46 , measures the flow rate of liquid in the main feed line  5 , downstream of pump  4 . The primary controller  43  receives a signal from the flow meter  46  indicative of the flow rate of liquid in main feed line  5 . Primary controller  43  communicates with the motor  48  for pump  4  to vary the speed of the pump, to vary the flow rate through the system and to create backpressure. 
         [0033]    Pressure sensor  47  is mounted on and extends into the manifold trunk  12 . The pressure controller  44  receives a signal from pressure sensor  47  indicative of the pressure of the liquid in main feed line  5 . Pressure controller  44  communicates the sensed pressure to primary rate controller  43  and valve controller  45 . Primary rate controller  43  communicates the sensed pressure to computer display  49  to display the information to an operator. Valve controller  45  communicates with and selectively opens and closes each of the valves  37 - 40  in response to changes in the pressure sensed by pressure sensor  47 . 
         [0034]    Operation of the system is described hereafter with reference to  FIG. 3  which comprises a logic diagram for the valve controller  45  of the embodiment shown in  FIGS. 1 and 2 . In an initial step  201 , first and second valves  37  and  38 , or A valves, are set open to allow liquid to flow through the group A distribution lines  21  and  22  and the smaller diameter branch lines  23 - 1  through  23 - 8  and third and fourth valves  39  and  40 , or B valves, are closed to prevent liquid from flowing through the group B distribution lines  26  and  27  and the larger diameter branch lines  28 - 1  through  28 - 8 . The pressure in group A distribution lines  21  and  22  and branch lines  23 , will increase as the rate controller  43  increases the pump speed and liquid flow. When the pressure sensed by pressure sensor  47  at  203  and communicated to valve controller  45  reaches a high pressure set-point, the valve controller will open the group B valves  39  and  40  at  205  allowing liquid to flow through group B distribution lines  26  and  27  and larger diameter branch lines  28 - 1  through  28 - 8  and closes the group A valves  37  and  38  at  207  preventing liquid from flowing through the group A distribution lines  21  and  22  and through the smaller diameter branch lines  23 . 
         [0035]    Because of the increase in the internal diameter of the tubing of the larger diameter branch lines  28  versus the smaller diameter branch lines  23 , the pressure in the distribution lines  7  and the main feed line  5  will initially decrease. If the pump speed is increased to further increase the flow rate of liquid through the distribution lines  7 , the pressure in the main feed line  5  will continue to increase. When the pressure sensed by pressure sensor  47  in the main feed line  5  reaches the high pressure set-point again at  209 , valve controller  45  will, at  211 , re-open the group A valves  37  and  38 , while leaving the group B valves  39  and  40  open so that liquid flows through both sets of distribution lines  21 ,  22 ,  26  and  27  and both sets of smaller and larger diameter branch lines  23  and  28 . In one embodiment the high pressure set point, might range between 50 to 75 psi and in the embodiment shown in  FIG. 3  is set at 65 psi for demonstrative purposes. 
         [0036]    With both group A and B valves  37 - 40  open, and when the flow is reduced by the rate controller, the pressure in the main feed line  5  and distribution lines  7  will drop. When the pressure sensed in the main feed line  5  by pressure sensor  47  drops below a minimum pressure set point as at  213 , the valve controller  45  is programmed to close the group A valves at  215 , blocking flow through the smaller diameter branch lines  23 . Once the group A valves are closed, the pressure in the group B distribution lines and the larger diameter branch lines  28  will initially increase to a pressure exceeding the minimum pressure set point, which in the embodiment shown in  FIG. 3  is set at 15 psi for demonstrative purposes. It is foreseen that set points ranging from approximately 10 to 20 psi could be utilized for the minimum pressure set point and that set points ranging from approximately 50 to 80 could be utilized for the maximum pressure set point. If flow continues to drop, the back pressure in the tubes will also continue to drop. When the pressure sensed in the main feed line  5  by pressure sensor  47  drops back down to the minimum set-point as at  217 , valve controller  45  will open the group A valves allowing flow to the smaller diameter branch lines and will close the group B valve resulting in increased back pressure throughout the distribution lines  7 . 
         [0037]    It is foreseen that a single valve could be utilized to control the flow of liquid to multiple group A or group B distribution lines. The valves used may be controlled electrically, hydraulically, pneumatically or by other known means. It is also foreseen that a single valve could be used to control the fluid to all of the lines with the valve having a first position in which the main feed line or trunk line is connected to each of and only the smaller diameter branch lines, a second position in which the main feed line is connected to each of and only the larger diameter branch lines, a third position in which the main feed line is connected to each of the smaller diameter branch lines and each of the larger diameter branch lines, and a fourth or closed position in which flow is cut off between the main feed line and the smaller diameter branch lines and the larger diameter branch lines. It is also foreseen that one such four way valves could be connected between the main feed line and each paired set of group A distribution lines and group B distribution lines, or in other words one four way valve per set of group A and group B distribution lines. 
         [0038]      FIGS. 4-7  disclose an alternative embodiment of a manifold and valve assembly  56  mounted on a larger bracket  57 . Manifold and valve assembly  56  includes four sets of group A valves  59  and four sets of group B valves  60  mounted on longer manifold branches  63  and  64  respectively projecting from manifold trunk  62 . Four sets of outlet tube connectors  67  and  69  are mounted on each manifold branch  63  and  64  respectively for connecting four sets of group A and group B distribution lines and branches (not shown) thereto. A pressure sensor  71  is shown mounted on the manifold trunk  62 . The manifold and valve assembly  56  are adapted to distribute liquid to each row of four sets of four row sections of the implement. 
         [0039]    The mounting bracket  57  includes a pair of slotted mounting bracket feet  76 . The slots  77  in feet  76  receive screws for bolting the bracket  57  to an implement frame. A vertical mounting plate  78  projects upward from the feet  76  and is adapted for mounting of the manifold trunk  62  and manifold branches  63  and  64  thereto. A valve controller  80  is mounted on the vertical mounting plate  78  at an upper end thereof. Side flanges  82  and  83  project rearward from the vertical mounting plate  78  on opposite sides thereof and are angled slightly inward towards each other. The side flanges  82  and  83  provide structural rigidity and strength to the bracket  57 . Valve position indicia  84  are shown stamped into the side flanges  82  and  83  to provide a reference to each valve  59  and  60  mounted on the bracket  57 . In the embodiment shown, the indicia include references A 1 , A 2 , A 3  and A 4  on one side flange  82  indicative of each of the group A valves  59  mounted adjacent thereto and references B 1 , B 2 , B 3  and B 4  on the other side flange  83  indicative of each group B valve  60 . A and B indicia  85  is also shown formed at the top of the bracket, to indicate which group of valves are included in each column and the group of distribution lines controlled thereby. 
         [0040]      FIG. 8  is an alternative embodiment of a liquid distribution system  101  for distributing liquid agricultural chemicals to each row of a row type implement in which the valves for controlling the flow of liquid out each line are mounted at each row instead of on a centrally mounted manifold and valve assembly as in the first two embodiments discussed herein. In system  101 , liquid is pumped from a tank  102 , using pump  104  and through main feed line  105  to a manifold  111 . A flow meter  112  is mounted on and measures the flow rate through main feed line  105  and a pressure sensor  113  is mounted on and measures the pressure within manifold  111 . 
         [0041]    Three liquid distribution lines  117 ,  118  and  119  are shown connected to the manifold  111 . Each liquid distribution line  117 - 119  extends to a different section of a row unit and four pairs of valves  120 , including A valves  120 A and B valves  120 B are connected to each liquid distribution line  117 - 119  with each valve pair  120  mounted on or positioned in close proximity to each row or row unit of the implement. Outlet tube connectors  123  A and  123 B are connected to each of the group A and group B valves  120 A and  120 B respectively. Branch tubes  125 A and  125 B are connected to each outlet tube connector  123 A and  123 B respectively, one set of which is shown in  FIG. 8 . The branch tube  125 A connected to outlet tube connector  123 A and associated with valve  120 A has a smaller internal diameter than the branch tube  125 B connected to outlet tube connector  123 B and associated with valve  120 B. A y-connector  127  is connected to the ends of the branch tubes  125 A and  125 B and a discharge tube  128  with a nozzle  129  on the distal end thereof is connected to the y-connector so that the liquid distributed through branch tubes  125 A and  125 B are dispensed out of a common nozzle  129  or outlet opening. 
         [0042]    A controller or control assembly  132  communicates with the flow meter  112 , pressure sensor  113 , pump  4  and each of the valves  120 A and  120 B to implement a control strategy similar to that used with the liquid distribution system  1 . 
         [0043]    It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.