Abstract:
A liquid metering system for an agricultural implement is modular, having individual metering pumps for each crop row. The pumps are individually controlled for precise application of the liquid input and are preferable electrically driven. A common pump is used, making the system modular in that varying sizes of implements can be produced by varying the number of pumps. A common supply line is used to supply a liquid input from a reservoir to the pumps. Each pump is connected to the common supply line. By connecting each pump to the common supply line, the difficulty of routing individual hoses from a central pump to each row unit are overcome.

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates to a liquid metering system for a machine such as an agricultural implement and in particular to a metering system that is modular and adapted to vary the quantity of common components depending on the width of the implement to which the system is installed. 
       BACKGROUND OF THE INVENTION  
       [0002]    Liquid fertilizer is commonly applied to an agricultural field before, during or after planting of a crop. A typical liquid fertilizer application system includes a tank for holding the liquid fertilizer, a pump for pumping the fertilizer from the tank, a plurality of distribution lines that eventually deliver the liquid to a delivery tube or spray nozzle, for placing the liquid on or in the soil near the plants. Down stream from the pump, various orifices, valves, etc are used to meter the volume of liquid directed to each crop row or outlet to deliver the desired application rate. The size of the pump is dependent on the width of the machine, i.e. the number of crop rows to be treated. Furthermore, the flow control orifices, and or valves must be customized for each row, taking into consideration the length of the line from the pump to the row. This adds considerable complexity to the manufacture of multiple machine models, types and widths. 
         [0003]    As the cost of fertilizers and other inputs to an agricultural fields increase, it becomes more important to precisely control the application of inputs to the field to avoid excess application rates, overlaps in application, application to non-crop areas, etc. One such system for doing so is described in U.S. Pat. No. 7,395,769. This patent describes a liquid application system with a single pump supplying liquid to a number of bypass valves, one for each row. The bypass valves are controlled to vary the rate of liquid application at each row. This system requires a liquid return line for the bypassed liquid. Furthermore, the size of the pump must vary over a full line of implements widths, or a single maximum sized pump is used on all implements, adding unnecessary cost to those implements not needing the full capacity of the pump. 
       SUMMARY OF THE INVENTION  
       [0004]    The liquid metering system of the present invention is modular, having individual metering pumps for each crop row. The pumps are individually controlled for precise application of the liquid input. A common pump is used, making the system modular. Implements of different widths can be produced by varying the number of pumps in the system. A common supply line is used to supply a liquid input from a reservoir to several or all of the pumps. Each pump is connected to the common supply line by a feeder line or could be directly coupled to the common supply line. The feeder lines are all identical. By connecting each pump to the common supply line, the difficulty of routing individual hoses from a central pump to each row unit are overcome. The only component that varies for different implement widths is the common supply line, which varies in length as it extends widthwise of the implement. The common supply line can be made modular as well with a section added for each row unit of additional implement width. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0005]      FIG. 1  is side view of planter having the liquid metering system of the present invention; 
           [0006]      FIG. 2  is a top view of a section of the implement of  FIG. 1 ; 
           [0007]      FIG. 3  is a schematic view of the liquid metering system of the present invention; and 
           [0008]      FIG. 4  plan view of the planter shown in  FIG. 1  coupled to a tractor. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0009]    The liquid metering system of the present invention is shown installed on the implement  10  in  FIG. 1 . Implement  10  is a planter but could be a grain drill, air seeder, seedling planter, bulb planter, etc where it is desired to apply a liquid, such as fertilizer. The metering system will be described in the context of a planter but is not limited to use on a planter, but could be used on-an implement dedicated solely to a liquid application. 
         [0010]    Implement  10  generally includes a plurality of row units  12  with each row unit  12  being substantially identical (although left hand and right hand units  12  may be provided, as required for the specific application). Only one row unit  12  is shown in  FIG. 1  for simplicity sake. Each row unit  12  is connected to a tool bar  14  that is part of a frame  16  of the planter/implement. The frame  16  may be provided with multiple support wheel assemblies  17  shown in  FIGS. 2 and 4 , which may be of conventional design. Furthermore the frame  16  is coupled to a traction unit, such as an agricultural tractor  72  shown in  FIG. 4 . The row unit  12  includes a frame  18  mounted to the tool bar  14  through a linkage  20  that allows up and down relative movement between the row unit and tool bar. The row unit frame carries a seed meter  22 , furrow opener  24 , seed tube (not shown), gauge wheel(s)  26  and a furrow closer  28  for the purpose of planting seed. 
         [0011]    As shown, a fertilizer applicator assembly  30  is shown with one assembly  30  provided for each planter row unit  12 . The fertilizer applicator assembly includes a frame assembly  32  having a first member  34  coupled to the to the tool bar  14  forward of the row unit  12 . A second frame member  36  is rotational mounted to the first frame member  34  at a pivot  35  and is biased downward by a spring  38 . A fertilizer opener  40  is carried by a frame member  36 . The depth of penetration of the fertilizer opener  40  is controlled by gauge wheel  42  also carried by the frame member  36 . Alternatively, the fertilizer opener could be mounted to the row unit frame  12 . Other variations in the fertilizer applicator assembly and its mounting to the planter will be readily apparent to those skilled in the-art. 
         [0012]    The fertilizer applicator assembly  30  opens a trench in the soil into which fertilizer is deposited. In this case a liquid fertilizer is applied. However the assembly  30  can be adapted to apply dry or gaseous fertilizers in well known manners. First and closing discs  44 ,  46  follow closely behind the gauge wheel  42  to close the furrow after the liquid, such as fertilizer, is applied. The fertilizer applicator assembly  30  is only shown as an example implement to which the liquid metering system of the present invention is installed. It will be apparent to one of ordinary skill that the metering system of the invention, described below, may be used with any of a variety of fertilizer opener/closer mechanisms. 
         [0013]    The modular liquid metering system  50  includes, for each fertilizer applicator assembly  30 , a metering pump  52  mounted to the tool bar  14 . Metering pump  52  can be of a variety of positive displacement pumps. Metering pump  52  is driven by an electric motor  54 , which is controlled as described below, to start, stop and vary the rate of liquid delivered by the pump  52 . In a preferred embodiment, the pump and motor are integral as a single unit. The pump outlet  56  is connected to a delivery tube  58 . A lower end of the tube  58  is attached to a boot/scraper  62 , partially shown so as to position the discharge end  64  of the delivery tube  58  within the furrow formed by the fertilizer opener  30  to deliver liquid fertilizer thereto. A nozzle and/or check valve may be provided at the discharge end  64 . 
         [0014]    The metering system  50  further includes a common supply line  66  attached to the tool bar  14  and extending transversely to the implement working direction shown by arrow  48 . Preferably the metering pumps are flow through pump such that they are arranged in-line with the common supply line and form a part thereof. The liquid flows through the pump to those pumps down stream there from. An internal pump inlet receives liquid flowing through the pump body. The common supply line  66  is formed by multiple pumps and extension tubes  67  between each pump. More pumps  52  and extension tubes  67  are added as the machine width increases with more row units. The pump at the downstream end is closed by a cap  69 . Alternatively, the common supply line  66  can be equipped with multiple T-fittings coupled to metering pumps that are not part of the common supply line. 
         [0015]    The common supply line  66  is coupled to a tank or liquid reservoir  68  in a conventional manner. Liquid from the reservoir  68  is gravity fed to the common supply line  66  and to the individual metering pumps  52 , thus eliminating the need for a central pump near the reservoir  68  to deliver metered liquid to each individual row unit. However, for very wide implements, a pump at the reservoir or line  68  may be beneficial to ensure adequate supply of liquid to the individual metering pumps  52 . Various shut off valves (not shown) can be placed between the reservoir  66  and the pumps  52  as needed to facilitate servicing of the system if desired. 
         [0016]    The common supply line  66  may be a single line extending the width of the implement. If the frame  16  is a folding frame, the supply line  62  may included flexible portions to accommodate the frame folding. Alternatively, each section of the frame may have its own common supply line, each common supply line being connected to the reservoir  68  and adapted to accommodate the frame folding. In such an application, the common supply line on a given section of the frame supplies liquid to all of the metering pumps  52  on that section of the frame. 
         [0017]    The metering system  50  is modular in that as the width of the implement increases, the manufacturer adds to the length of the common supply line  66  and adds additional common pumps  52 , electric motors  54  and application tubes  58 . Each of these are identical for each row, thus the number of different parts and part numbers that a manufacturer or service provider must stock and manage is minimized. This is in contrast to liquid delivery systems that employ a single pump at the reservoir. In such an instance, unique pumps are required for different width implements to meter liquid to differing number of liquid applicator assemblies  30 . Various valves, flow dividers, etc must be employed to meter the desired rate of liquid to each of the rows, making it more difficult to control the application rate at the individual row. 
         [0018]    A schematic drawing of the modular liquid metering system  50  is shown in  FIG. 3 . The simplicity of the system, with individual metering pumps for each row is shown. With reference to  FIG. 4 , the implement  10  is shown coupled to the tractor  72 . Each motor  54  of the metering system  50  is electrically connected to a controller  70 , typically mounted to the tractor  72 . Also carried by the tractor and coupled to the controller is a GPS receiver  74 . The controller has a memory that stores field information including the size and shape of the field in which the implement is operating as well as green areas in the field that do not need liquid application. The field information may also include agronomic information about the field, such as soil type, etc. Application rates for some liquid inputs, such as fertilizer, may vary depending on soil type, etc. The GPS receiver supplies signals to the controller in real time regarding the geospatial location of the implement. The controller uses the signals to determine the location of the implement in the field, the direction of travel and the speed of travel. The controller uses both the GPS and the field information to control the application rate of each pump according to a prescription as the implement is moved through the field. The controller and varies the speed of the motors  54  accordingly, to vary the speed of, or turn on and off, the pumps  52 . In addition, the controller  70  uses the field information and the path of the implement to avoid applying liquid on overlaps, headlands, waterways, point rows, etc. where it is not desired to apply the liquid. This reduces input costs and reduces the environmental impact of the use of the liquids. 
         [0019]    By locating the pumps at the row unit, a change in the liquid application rate at the pump  52  is almost immediately experienced at the tube discharge end. In addition, long hoses extending form a flow divider to each row unit are avoided and the difficulty in routing such hoses and ensuring all are the same length for metering and avoiding any kinks in the hoses. 
         [0020]    Electric power for the motors  54  can be provided by the tractor electrical system or by a separate generator on the tractor or implement. An implement mounted generator could be powered by an engine, PTO, or by ground engaging wheels  17  on the implement, etc. The application rate by location for each pump can be recorded by the controller and the data used for management of the field. In addition, the application rate can be displayed to the operator by a display  76  on the tractor  72 . 
         [0021]    While the invention is described using electric motors as variable speed drive mechanisms to drive the pumps  52 , it is understood that other variable speed drive mechanisms may be used in place of the electric motors such as, but not limited to, hydraulic motors, variable speed mechanical transmissions, etc. 
         [0022]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.