Abstract:
A system ( 1 ) and method for coating seeds with a treatment liquid, in which transfers of seeds and liquid within the system arc controlled by a control assembly ( 6 ) in accordance with selectable operational modes. Some modes involve determining an actual amount of a quantity and/or a subquantity of seeds transferred from a bin ( 24 ) based on a change in the weight of seeds remaining in the bin ( 24 ), and adjusting the system ( 1 ) to account for a difference between the actual and expected amounts. Other modes involve determining an actual amount of a quantity and/or a flowrate of liquid transferred from a tank ( 750 ) based on a change in the weight of liquid remaining in the tank ( 750 ), and adjusting the system ( 1 ) to account for a difference between the actual and expected amounts. Further, these modes can be performed together for even greater redundancy and accuracy.

Description:
RELATED APPLICATIONS 
       [0001]    The present non-provisional patent application is related to and claims priority benefit of an earlier-filed provisional application titled “High Redundancy Seed Coating Apparatus and Method”, Ser. No. 62/148,284, filed Apr. 16, 2015. The entire content of the identified earlier-filed application is hereby incorporated by reference into the present application. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is directed to improved seed coating systems and methods allowing users to select different modes of operation and control of the system components. More particularly, the invention is concerned with such apparatus and methods using a seed coating apparatus having a seed bin assembly, a seed metering wheel below the bin assembly, a liquid coating delivery assembly, and coating apparatus designed to receive seed and coat the seed with liquid. An electronic control assembly is employed to selectively operate the seed bin and liquid coating delivery assemblies in different modes, depending upon the desire of the operator and the conditions of seed treatment. 
       SUMMARY OF THE INVENTION 
       [0004]    A system and method for coating seeds with a treatment liquid, in which transfers of the quantities of seeds and liquid within the system are controlled by an electronic control assembly in accordance with one or more selectable operational modes. 
         [0005]    In a first embodiment, a system for coating seeds with a liquid may broadly comprise a seed bin assembly, a seed metering assembly, a liquid delivery assembly, a coating apparatus, and an electronic control assembly. The seed bin assembly may include a seed bin for containing the seeds, an outlet device for transferring a quantity of the seeds from the seed bin, and a seed weight sensor for determining a weight of the seed in the seed bin. The seed metering assembly may meter the transfer of the quantity of the seeds, including metering the quantity of the seeds as a plurality of subquantities. The liquid delivery assembly may include a reservoir for containing the liquid and may transfer a quantity of the liquid from the reservoir. The coating apparatus may receive the quantity of the seeds and the quantity of the liquid, and may include an atomizer for applying the quantity of the liquid to the quantity of the seeds, and a drum dryer for drying the coated seeds. The electronic control assembly may be configured to operate the seed bin assembly and the seed metering assembly in the following selectable modes. A first mode may involve determining an actual amount of the quantity of the seeds transferred from the seed bin based on a change in the weight of the seeds remaining in the seed bin after each transfer as indicated by the seed weight sensor, and adjusting operation of the seed metering assembly so that the actual amount of the quantity of the seeds matches an expected amount of the quantity of the seeds. A second mode may involve determining an actual amount of each subquantity of the seeds included in the quantity of seeds transferred from the seed bin based on a change in the weight of the seed remaining in the seed bin after each transfer as indicated by the first weight sensor, and adjusting operation of the seed metering assembly to account for a difference between the actual amount of the subquantity of the seeds and an expected amount of the subquantity of the seeds. 
         [0006]    In a second embodiment, a system for coating seeds with a treatment liquid may broadly comprise a seed bin assembly, a seed metering assembly, as liquid delivery assembly, a coating apparatus, and an electronic control assembly. The seed bin assembly may include a seed bin for containing the seeds, an outlet device for transferring a quantity of the seeds from the seed bin, and a first weight sensor for determining a weight of the seeds in the seed bin. The seed metering assembly may meter the transfer of the quantity of the seeds. The liquid delivery assembly may include a reservoir for containing the liquid, as valve and a pump for transferring a quantity of the liquid from the reservoir, a flow metering assembly for metering the transfer of the quantity of the liquid, and a liquid weight sensor for determining the weight of the liquid in the reservoir. The coating apparatus may receive the quantity of the seeds and the quantity of the liquid, and including an atomizer for applying the quantity of the liquid to the quantity of the seeds, and a drum dryer for drying the coated seeds. The electronic control assembly may be configured to operate the liquid delivery assembly in the following selectable modes. A first mode may involve determining an actual amount of the quantity of the liquid transferred from the reservoir based on a change in the weight of the liquid remaining in the reservoir after each transfer as indicated by the liquid weight sensor, and adjusting operation of the flow metering assembly so that the actual amount of the quantity of the liquid matches an expected amount of the quantity of the liquid. A second mode may involve determining an actual flow rate of the transfer of the liquid from the reservoir, and adjusting operation of the liquid delivery assembly to account for a difference between the actual flow rate and an expected flow rate. 
         [0007]    In a third embodiment, a system may provide both the selectable modes of the first embodiment and the selectable modes of the second embodiment for even greater redundancy and accuracy 
         [0008]    Various implementations of the foregoing embodiments, may include any one or more of the following features. The seed bin assembly may include a plurality of adjacent seed bins. The outlet device may be a sliding gate configured to slide between a first position in which the quantity of the seeds flow from the seed bin assembly to the coating apparatus, and a second position in which the quantity of the seeds does not flow, and the electronic control assembly may be further configured to control movement of the sliding gate between the first position and the second position. With regard to the first embodiment, the seed metering assembly may include a rotatable seed wheel having a plurality of pockets, and each pocket may be configured to define the subquantity of the seeds. Adjusting operation of the seed metering assembly may include adjusting a speed of rotation of the rotatable seed wheel. The electronic control assembly may be further configured to operate the seed bin assembly and the seed metering assembly in a third mode which involves performing both the first and second modes. With regard to the second embodiment, adjusting operation of the liquid delivery assembly may include adjusting one or both of a position of the valve and a speed of the pump. The electronic control assembly may be further configured to operate the liquid delivery assembly in a third mode which involves performing both the first and the second modes. The electronic control assembly may be further configured to operate the liquid delivery assembly in a seventh mode which involves performing at least one of the first mode and the second mode and at least one of the third mode and fourth mode, or in an eighth mode which involves performing all of the first mode, the second mode, the third mode, and the fourth mode. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a high-level block diagram illustrating a seed treating system in accordance with the invention; 
           [0010]      FIG. 2A  is a schematic flow diagram illustrating three alternate modes of operation controlling the flow of seeds from a seed hopper; 
           [0011]      FIG. 2B  is a schematic flow diagram illustrating three alternate modes of operation controlling the flow of coating liquid from a liquid tank; 
           [0012]      FIG. 3  is a perspective view of a preferred decreasing mass seed hopper assembly shown in conjunction with a seed treater; 
           [0013]      FIG. 4  is a fragmentary side elevational view of the assembly depicted in  FIG. 3 , with the treater inlet illustrated in phantom; 
           [0014]      FIG. 5  is a plan view of the seed hopper assembly; 
           [0015]      FIG. 6  is a bottom view of the seed hopper assembly; 
           [0016]      FIG. 7A  is a fragmentary vertical sectional view of the seed hopper assembly, and illustrating in detail the construction of the upper turret assembly; 
           [0017]      FIG. 7B  is a fragmentary vertical sectional view illustrating in detail the outlet assembly of the seed hopper assembly; 
           [0018]      FIG. 8  is an exploded perspective view of the seed hopper assembly; 
           [0019]      FIG. 9  is an exploded perspective view of the upper turret assembly of the seed hopper assembly; 
           [0020]      FIG. 10  is a fragmentary plan view of the seed hopper assembly, with the top wall of the turret assembly removed; 
           [0021]      FIG. 11  is a perspective view of the turret assembly, illustrating the spring-biased seal plate at the outlet of the turret assembly; 
           [0022]      FIG. 12  is a fragmentary perspective view illustrating the outlet assembly of the seed hopper assembly; 
           [0023]      FIG. 13  is a perspective view of a single bin of the seed hopper assembly; 
           [0024]      FIG. 14  is a fragmentary perspective view of an outlet of one of the bins of the seed hopper assembly; 
           [0025]      FIG. 15  is an exploded perspective view of the outlet illustrated in  FIG. 10 . 
           [0026]      FIG. 16  is a perspective view of a seed metering/seed treater assembly equipped with a rotatable seed metering wheel; 
           [0027]      FIG. 17  is a perspective view of the seed metering wheel assembly and seed delivery chute forming a part of the seed treater apparatus; 
           [0028]      FIG. 18  is a plan view of the apparatus illustrated in  FIG. 17 ; 
           [0029]      FIG. 19  is a vertical sectional view taken along the line  19 - 19  of  FIG. 18 ; 
           [0030]      FIG. 20  is a vertical sectional view taken along the line  20 - 20  of  FIG. 18 ; 
           [0031]      FIG. 21  is a top perspective view of the seed metering wheel assembly illustrated in  FIG. 16 ; 
           [0032]      FIG. 22  is a bottom perspective view of the seed metering wheel assembly illustrated in  FIG. 21 ; 
           [0033]      FIG. 23  is an exploded perspective view of the seed metering wheel assembly; 
           [0034]      FIG. 24  is an exploded perspective view of the apparatus depicted in  FIGS. 17-20 ; 
           [0035]      FIG. 25  is a perspective view of an alternate seed metering assembly in the form of a rotatable metering gate; 
           [0036]      FIG. 26  is a plan view of the metering gate assembly; 
           [0037]      FIG. 27  is an end view of the metering gate assembly; 
           [0038]      FIG. 28  is a side elevational view of the metering gate assembly; 
           [0039]      FIG. 29  is a vertical sectional view taken along line  29 - 29  of  FIG. 26 ; 
           [0040]      FIG. 30  is a view taken along line  30 - 30  of  FIG. 26 ; 
           [0041]      FIG. 31  is an enlarged fragmentary view taken along line  31 - 31  of  FIG. 26 ; 
           [0042]      FIG. 32  is an enlarged fragmentary view depicting the drive cylinder for the metering gate assembly; 
           [0043]      FIG. 33  is a perspective view of another seed metering wheel design; 
           [0044]      FIG. 34  is a plan view of the seed metering wheel of  FIG. 33 ; 
           [0045]      FIG. 35  is an upper, perspective, exploded view depicting the components of the seed metering wheel of  FIG. 33 ; 
           [0046]      FIG. 36  is a lower, perspective, exploded view depicting the components of the seed metering wheel of  FIG. 33 ; 
           [0047]      FIG. 37  is a vertical sectional view taken along the line  37 - 37  of  FIG. 34 ; 
           [0048]      FIG. 38  is a vertical sectional view taken along the line  38 - 38  of  FIG. 34 ; 
           [0049]      FIG. 3916  is a vertical sectional view taken along the line  39 - 39  of  FIG. 34 ; and 
           [0050]      FIG. 40  is a top view illustrating the seed metering wheel of  FIG. 33  within the overall seed metering assembly; 
           [0051]      FIG. 41  is a front perspective view of a liquid treatment delivery assembly in the form of a pump stand; 
           [0052]      FIG. 42  is a rear perspective view of the pump stand depicted in  FIG. 41 ; 
           [0053]      FIG. 43  is a schematic flow diagram illustrating the preferred electronic processor control of the pump stand, during the flow rate metering mode and combined modes of operation of the liquid delivery coating assembly; 
           [0054]      FIG. 44  is a perspective view of a single batch seed hopper in conjunction with a seed treater; 
           [0055]      FIG. 45  is a perspective view, with parts removed, of the seed hopper illustrated in  FIG. 44 ; 
           [0056]      FIG. 46  is a front perspective view of another pump stand useful in carrying out the invention and equipped with a conical tank; 
           [0057]      FIG. 47  is a rear perspective view of the pump stand illustrated in  FIG. 46 ; 
           [0058]      FIG. 48  is a front perspective view of another pump stand useful in carrying out the invention and equipped with a tote or keg tank; and 
           [0059]      FIG. 49  is a rear perspective view of the pump stand illustrated in  FIG. 48 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0060]    The present invention provides methods and apparatus for improved, highly accurate control of the amount of seeds which are delivered from one or more seed bins, and coating liquid from a liquid tank or other reservoir, to a downstream treater/coater device. 
         [0061]    Generally speaking, the invention provides a system  1  including a series of interconnected, assemblies providing high-redundancy, very accurate treatment of seeds with various treating liquids. As illustrated in  FIG. 1 , the system  1  of the invention broadly includes a decreasing mass (loss-in-weight) hopper or bin assembly  2 , a seed metering assembly  3 , a seed treater assembly  4 , and a liquid treatment delivery assembly  5 . The assemblies  2 - 5  are operably connected with and controlled by control assembly  6 , typically in the form of one or more programmable logic controller (PLCs). 
         [0062]    The assembly  2  includes appropriate weighing devices to continuously determine the weight of seeds within the bin assembly, typically in the form of one or more load cells supporting the seed bin(s). This allows continuous determination over time of the loss of weight in the bin(s). The seed metering assembly  3  is preferably in the form of a rotatable seed wheel assembly or a rotary gate assembly, which receives seed from the weigh bin assembly  2 . The seed treater assembly  4  is itself conventional, and includes an inlet for a quantity of seeds delivered from the seed metering assembly  3 , and is equipped with a liquid treatment applicator or atomizer and a rotatable drum dryer. The liquid treatment delivery assembly  5  is also coupled with the seed treater assembly  4  for delivering a quantity of treatment liquid to the applicator of the assembly  4 , and has a liquid tank or other reservoir, a weigh scale, and selectively operable pump and valve structures for delivery of liquid from the tank. 
         [0063]      FIGS. 2A and 2B  illustrate that the seed bin and liquid coating delivery assemblies can be alternately operated in separate modes, depending upon operator preference and conditions of the equipment. These are, respectively, decreasing mass modes for the seed and liquid, seed metering mode, flow rate metering mode, and combined modes. In the latter case, the accuracy of seed coating is enhanced owing to sequential re-calibration of the outputs from the seed bin assembly and liquid coating delivery assembly, during the course of seed treating. 
         [0064]    In order to facilitate an understanding of the invention, and specifically the illustrated system  1 , the individual subassemblies  2 - 5  and controller  6  will be separately described. 
         [0065]    Turning now to  FIGS. 3-15 , a seed treater system  20  is illustrated in  FIG. 3  and broadly includes a seed treater assembly  4  and a multiple-bin decreasing mass seed hopper/handling assembly  24  situated above the assembly  4 . The treater system  20  is designed to coat agricultural seeds with any one of a number of selected, treating agents, and to deliver the treated seeds in known quantities to a conveyor or other exit device (not shown). 
         [0066]    The seed treating assembly  4  is itself conventional and includes an upper, open-top inlet  26 , a treating chamber  28  and an outlet chute  30 . A variety of commercially available treating units may be used in the overall seed treater system  20 . Preferably, the assembly  4  is one of the treaters sold by USC, LLC of Sabetha, Kans. 
       Hopper Assembly 2 
       [0067]    The preferred seed handling assembly  24  generally includes frame structure  32 , a plurality (here three) of juxtaposed, identical seed bins  34 , and a rotary turret assembly  36  designed to supply incoming seed to each of the bins  34 . As illustrated, the seed handling assembly  24  is operable to deliver seed to the inlet  26  of treating assembly  4 . 
         [0068]    The frame structure  32  includes three equidistantly spaced, upright, sectionalized support legs  38  with intermediate cross-braces  40  extending between the legs  38 . An inwardly extending support beam  42  is secured to the upper end of each of the legs  38  and has an innermost apertured connection plate  44 . A triangular turret frame  46  having apex-mounted, apertured connection flanges  47  is positioned atop and secured to the midpoints of the support beams  42  by means of threaded connectors  48  extending through the flanges  47  and beams  42 . 
         [0069]    Each bin  34  (see  FIG. 13 ) has a top wall  50 , with an outermost arcuate margin  52 , an inner margin  54 , and a pair of inwardly extending, converging side margins  56 . Each top wall  50  is a truncated conical sector. Accordingly, each top wall  50  in plan configuration approximates a sector of a circle, and particularly a  120  section. In preferred forms, the top wall  50  is not a complete sector, but is truncated by the inner margin  54 . The bin  34  also has depending sidewall structure  58  including an arcuate upper section  60  depending from arcuate margin  52 , and an inwardly tapered arcuate lower section  62  extending from the lower margin of the section  60 . Each section  62  is also a conical sector, so that in a bottom view the sections  62  are in the shape of an approximate sector of a circle. 
         [0070]    A pair of upright, substantially planar sidewalls  64  depend from the side margins  56 . The inboard ends of the sidewalls  64  are interconnected by means of a planar segment  68 . The top wall  50  and sidewall structure  58  are interconnected in order to define a seed holding interior space. The inner margin  54  of top wall  50  and the upper margins of the sidewalls  64  and segment  68  cooperatively define a seed inlet  70 . 
         [0071]    Each bin  34  is equipped with a generally U-shaped support bail  72  having upwardly extending legs  74  at the juncture between the margins  52  and  56 , with a cross-rail  76  secured to the upper ends of the legs  74 . A load cell  78  is secured to the midpoint of cross-rail  76  by means of a lower clevis  80 . The upper end of each load cell  78  is secured by means of an upper clevis  82  threaded to the lower end of the adjacent connector  48 , so as to suspend each bin  34  from the associated support beam  42 . In order to provide more precise weight control, a plurality of load cells  78  may be used in lieu of a single cell. A stabilizing assembly  84  is centrally secured to the upper surface of top wall  50  and includes a U-shaped body  86  and an upwardly inclined, apertured, generally triangular connector plate  88 . A pair of adjustable links  90  are secured to the sidewalls of body  86  with the remote ends thereof attached to stabilizer beams  92  affixed to the adjacent support leg  38  of frame structure  32 . An adjustable link  94  is connected between the plate  88  and a flange  95  forming a part of one of the beams  92 . A conventional bin full sensor  96  is attached to top wall  50  and has an inwardly extending probe  98  ( FIG. 7A ). 
         [0072]    Referring now to  FIGS. 7B and 13-15 , the lower outlet end of each bin  34  is depicted. Specifically, the tapered, lower arcuate sidewall section  62  has a lower opening  100 . A delivery chute  102  comprising sidewalls  104  and end walls  106  depends from the lower end of the bin and has a surrounding box-like mounting flange  108 . The opening  100  and delivery chute  102  thus define a lower seed bin outlet  110 . 
         [0073]    In order to selectively regulate the flow of seed from outlet  110 , the bin  34  is equipped with a slide gate assembly  112  and a multiple-chute assembly  114 . The slide gate assembly  112  includes a primary frame  116  with a through-opening  118 . A selectively shiftable slide gate  120  is supported by the frame  116  and is shiftable in a fore-and-aft fashion between a fully closed position blocking flow of seed through the opening  118 , and an infinite number of partially open intermediate positions and a full-open position. Each slide gate assembly  112  has a sensor for detecting whether the slide gate  120  is in a closed or open position. Movement of the slide gate  120  is effected by means of a double-acting pneumatic piston and cylinder assembly  122  equipped with an open slide gate position sensor. A control valve  124  is also supported on the primary frame  116  and is operatively coupled with the pneumatic cylinder and an electronic controller (not shown) which controls the operation of the assembly  122 . As illustrated in  FIGS. 13 and 14 , the primary frame  116  is designed to mate with the flange  108 , such that the lower seed outlet opening  110  is in registry with through-opening  118 . In the context of the present invention, the slide gate assembly  112  is in the full-closed position when the bin is not delivering seed, and is in the full-open position when seed is being delivered therefrom. 
         [0074]    The chute assembly  114  is secured to the underside of primary frame  116  and comprises a relatively narrow central chute  126  and a pair of oppositely outwardly extending wider chutes  128 . Seed delivered through opening  118  is thus separated into three individual streams by the chutes  126 ,  128 . However, the use of multiple chutes is not essential in carrying out the present invention, i.e., the seed from each bin  34  can fall directly from the slide gate assembly  112  into subassembly B or C. 
         [0075]    In order to stabilize the lower end of the bin  34 , a pair of oppositely outwardly extending adjustable links  130  are connected to the chute  102  and the adjacent cross-braces  40 . To this end, the cross-braces  40  are provided with central, inwardly extending stubs  132 , and the links  130  are interconnected between flanges  134  on the stubs  132 , and flanges  136  on the chute  102  (see  FIGS. 12-13 ). 
         [0076]    The turret assembly  36  is best illustrated in  FIGS. 7A and 9 . The assembly  36  generally has a stationary turret mount  138  and a rotary turret  140  within the mount. The mount  138  is hexagonal in configuration, having a bottom wall  142  equipped with a central bearing opening  143 , six interconnected, upstanding sidewalk  144 , and an uppermost, circumscribing mounting lip  146 . The bottom wall  142  has three equidistantly spaced through-openings  148 . The sidewalls  144  support three equidistantly spaced location sensors  149  which are designed to sense the position of turret  140 . Three flexible tubular guides  150  are secured to the underside of bottom wall  142  in registry with the corresponding openings  148 . The turret mount  138  is supported on turret frame  46  with the lip  146  overlying the bars making up frame  46  ( FIGS. 5 and 7A ). 
         [0077]    The turret  140  comprises a cylindrical housing  152  including a bottom wall  154 , upstanding, circular sidewall  156 , and a top wall  158  having, a central inlet opening  160 . A sensor element  155  is secured to the outer surface of sidewall  156  and is oriented to be sensed by the location sensors  149 . The housing  152  is equipped with a central drive shaft  162  secured by a coupler  164  and extending below bottom wall  154 . The bottom wall  154  also has an offset outlet opening  166 , with an apertured seal plate  168  positioned below the opening  166  and in registry therewith. The seal plate  168  is secured to bottom wall  154  by means of connecting bolts  170  passing through the plate  168  and threaded into bottom wall  154 , with conical springs disposed about each bolt  170 . An obliquely oriented chute  172  is located within housing  152  and has a lower opening  174  with a short, downwardly extending, tubular transition  176 . 
         [0078]    A drive unit  178  ( FIGS. 7A and 8 ) is located beneath the turret mount  138  and includes an electric drive motor  180  having an output sprocket  182  and a drive chain  184  trained about the sprocket  182 . The chain  184  is also trained about a clutch assembly  185  receiving shaft  162 . The sprocket  182 , chain  184 , and clutch assembly  186  are located within the surrounding housing  188 . The latter has an upstanding, tubular bearing assembly  190 . 
         [0079]    As best seen in  FIG. 7A , the turret  140  is received within the turret mount  138 , with the drive shaft  162  extending through the bearing assembly  190  and clutch assembly  186 , such that the turret  140  is rotatable relative to the turret mount  138 . Hence, operation of motor  180  serves to rotate turret  140 , as will be described in detail below. 
         [0080]    In practice, three of the bins  34  are supported in juxtaposed relationship by the frame structure  32 , so that the grouped bins present a substantially circular configuration in plan. Each such bin is supported by one or more load cells  78 , the latter interconnected between an upper support beam  42  and an underlying bail  72 . In this orientation, the sidewalk  64  of the bins  34  are in close, parallel adjacency, and the flexible tubular guides  150  extend into the corresponding bin seed inlets  70 , and the tapered sidewall sections  62  converge towards a common lower apex. The three chute assemblies  114 , being closely adjacent and near the bottom of the respective bins, are sized to be received within the inlet  26  of seed treater system  20 . The stabilizing couplers  90 ,  94 , and  130  serve to maintain the position of the suspended bins  34  within the frame structure  32 . 
         [0081]    Control of the seed handling assembly  24  is accomplished through one or more programmable electronic controllers, including but not limited to controller  6 , which are suitably connected with the aforementioned sensors, load cells  78 , control valves  124 , and the drive motor  180  and clutch assembly  186  forming a part of the turret drive unit  178 . The controller(s) are appropriately programmed to carry out the operation of assembly  24 , as described below. 
       Operation 
       [0082]    In the operation of the decreasing mass seed hopper/bin assembly  24 , incoming seed is delivered through the turret central inlet opening  160  by any convenient means. Typically, this is effected by an inclined conveyor leading from a supply of seed to the opening  160 . The incoming seed is sequentially diverted to each of the bins  34  by appropriate positioning of the rotary turret  140  within turret mount  138 , so that the lower opening  174 , the opening of seal plate  168 , and transition  176  of the chute  172  come into registry with one of the through-openings  148  of bottom wall  142 . This is illustrated in  FIGS. 7A and 10  where the opening  174  and transition  176  are in registry with one of the openings  148 , with the other two openings circumferentially spaced from the one opening  148 . Seed is delivered to the associated bin  34  by passage along chute  172 , through opening  174  and transition  176 , and ultimately through the guide  150  into the interior of the bin. 
         [0083]    As seed accumulates within one of the bin  34 , the weight of the bin is monitored by the associated load cell(s)  78  and bin full sensor  96 . When the one bin is filled to the desired degree, the turret  140  is shifted or indexed via turret drive unit  178  so that the lower opening  174  and transition  176  of turret  140  come into registry with the next adjacent opening  148  and guide  150 , and the process is repeated. During such movement, the spring-biased seal plate  168  engages the upper surface of bottom wall  142 . Precise positioning of the turret  140  is obtained by means of the position sensors  149  and sensor element  155 . In this fashion, the turret  140  successively diverts seed to and fills the three bins  34 . 
         [0084]    Simultaneously with this stepwise filling of the bins  34 , seed is delivered through the lower bin outlets  110 , slide gate assemblies  112 , and multiple-chute assemblies  114 ; however, seed is not added to a bin  34  while seed is being delivered therefrom. Flow of seed is controlled by the respective positions of the slide gate assemblies  112 . Thus, the seed travels from the seed bins  34 , through delivery chutes  102  and through-openings  118 , as governed by positions of the slide gates  120 . 
         [0085]    The bins  34  are sequentially filled and emptied using known decreasing mass techniques so that a substantially even supply of seed is delivered to the underlying seed metering assembly  3 . As explained, more fully below, the decreasing mass data derived from assembly  2  is used as an input to controller  6 . 
         [0086]    Although the foregoing description refers to the use of a three-bin apparatus, which is commercialized by USC, LLC of Sabetha, Kans. under the trademark Tri-Flo®, the invention is not so limited. That is to say, a single bin decreasing mass seed hopper assembly could be employed, so long as it is equipped with an appropriate outlet valve or gate and weighing devices permitting calculation of loss in weight during operation. Such an option is described with reference to  FIGS. 44 and 45 . 
       Assemblies  2 / 3 —Seed Metering/Seed Treater Assemblies 
       [0087]    Referring now to the  FIGS. 16-24 , a combination device  310  is depicted, broadly comprising a seed metering assembly  3  interconnected with a seed treater assembly  4 . The illustrated seed treater assembly  4  includes a metering seed wheel assembly  312 , which directs incoming seed from the decreasing mass seed hopper assembly  2  into an atomizer  314  where the seeds are coated with chemical(s). The preferred atomizer is described in U.S. Pat. Nos. 6,551,402 and 6,783,082, incorporated by reference herein. The coated seeds are then dried within a downstream rotating drum dryer  316 , and the finished seeds are delivered by way of an outlet for storage or use. 
         [0088]    The seed metering wheel assembly  312  broadly includes an uppermost hopper assembly  320 , an intermediate metering assembly  322 , a lower plate assembly  323 , and a lowermost delivery chute  324 , which is secured to the inlet end of atomizer  314 . 
         [0089]    The hopper assembly  320  includes a housing  326  having an upright tubular sidewall  327 , circular upper and lower connection flanges  328  and  336 , a pair of opposed vents  332 , and a series of removable access plates  354 . A unitary seed-receiving hopper  34  having a connection flange  336  is positioned within the confines of housing  326 , such that the flanges  336  and  330  mate and are connected via fasteners (not shown). The hopper  34  has an arcuate center line apex  338  with identical, downwardly extending, arcuate wall sections  340  and  342  each equipped with an identical, generally triangularly-shaped seed outlet opening  344  or  346 ; the latter have downwardly extending, defining wall structures  348  or  350 . If desired, a tubular extension  355  ( FIG. 16 ) may be attached to the upper end of housing  326  in order to increase the effective volume of the hopper assembly  320 . 
         [0090]    The seed metering assembly  322  is positioned below hopper assembly  320  and includes a stationary, tubular housing  356  with upper and lower connection flanges  358  and  360 . The upper flange  358  of housing  356  mates with lower flange  330  of assembly  320 , with appropriate fasteners serving to connect the flanges. The housing  356  supports a stationary channel  362 , which in turn supports a variable frequency device-controlled electrical drive motor  364  and gear box  366 . The channel  362  also supports a pair of outboard brackets  368  and  370  at the central region thereof. A pair of identical, generally triangular weldments  371  are respectively connected to the brackets  368  and  370  and extend outwardly and are supported by the housing  356 . The weldments  371  each include a pair of diverging box sidewalls  372 ,  374  and  380 ,  382 , as well as an outboard spacer  375  or  383 , and fasteners  376 ,  378  or  384 ,  386 . Proximity seed sensors  388  and  390  are respectively connected with box sidewalls  372  and  380 . A lowermost, radially extending brush  392  is secured to sidewall  374 , and an identical brush  394  is secured to sidewall  382 . It will be observed that the weldments  371  each define a substantially triangular through-opening  396  or  398 , and are respectively in registry with the seed outlet openings  344  and  346  of hopper assembly  320 . It will thus be appreciated that the openings  396 ,  398  are seed entrance openings for the metering assembly  322 . 
         [0091]    The overall metering assembly  322  also includes an axially rotatable metering wheel  400 , which is situated within the confines of housing  356 . The wheel  400  is of composite design (see  FIG. 23 ) and has a series of interconnected, apertured plates, namely an upper synthetic resin wheel plate  402 , an intermediate stainless steel reinforcing plate  404 , and a lower synthetic resin plate  406 . A circumscribing, upwardly extending seed retaining ring  408  surrounds the apertured plates and extends above the upper surface of plate  402 . The interconnected plates  402 - 406  have a central, hexagonal drive opening  409  and a series of seed metering openings  410  therethrough. In detail, the openings  410  are arranged in a total of three circular arrays  412 ,  414 , and  416 . The inner array  416  has a plurality of identical, truncated triangular through openings  418 ; the intermediate array  414  has a plurality of identical, elongated, arcuate openings  420 , which are in staggered relationship relative to the openings  418 . Finally, the outer array  412  has another series of identical, elongated arcuate openings  422 , which are staggered relative to the openings  420  of the intermediate array. It will further be observed that the openings  418 ,  420 , and  422  are each defined by circumscribing rib sections  418   a ,  420   a , and  422   a.    
         [0092]    The metering wheel  400  is rotated in a clockwise direction, as viewed in  FIG. 19 , by means of the motor  364  and gear box  366 . The box  366  has an elongated, hexagonal, vertically extending, rotatable drive shaft  424  with a lowermost, downwardly extending threaded shank  424   a  extending below the wheel  400 . The shaft  424  and hub  425  serve to rotate the wheel  400 , with the shaft  424  received within the central drive opening  409 . The operation of motor  364  is controlled by means of conventional wiring including electrical leads  426  and junction box  428  connected to control assembly  6 . 
         [0093]    Plate assembly  323  is stationary and includes an upper metallic wear plate  430  which engages the lower surface of wheel  400 , a synthetic resin foam support pad  432 , and a lowermost metallic floor plate  434 . The plates  430  and  432  have identical, opposed, outwardly diverging slots  436  and  438 , whereas plate  434  has similarly configured through openings  440 . The wear plate  430  has a pair of downwardly extending flanges  431  adjacent the edges of openings  436 , which direct seed downwardly as the seed exits the assembly  323 . The assembly  323  is mounted on shank  424   a , and an elongated bearing plate  442 , washer  444 , and nut  446  are used to mount the assembly  323 . 
         [0094]    The delivery chute  324  is generally frustoconical and has an uppermost connection flange  450 , a tapered hollow body section  452  and a lowermost connection flange  454 . The flange  450  is connected to the underside of the plate assembly  323  (with optional use of a spacer ring  456 ) by means of elongated connectors  458 . 
         [0095]    As is evident from the foregoing description, the seed metering wheel assembly  312  provides a hopper for receiving a quantity of seeds to be treated from the assembly  2 , with the seeds flowing by gravitation into the area immediately above the seed metering wheel  400 . This is monitored by a pair of proximity sensors  388  and  390  respectively located adjacent the weldment openings  396  and  398 . Thereupon, the seeds pass through the openings  396 ,  398 , and thence through the metering wheel  400  and the stationary openings  436 ,  438 , and  440  of plate assembly  323 . The quantity of seeds is then finally directed into and through the delivery chute  324  to the atomizer  314  of seed treater assembly  4 . 
         [0096]    The passage of seed through the metering wheel  400  is of prime importance. That is, as the wheel  400  rotates, the especially designed and configured seed metering openings  418 ,  420 , and  422 , and the corresponding opening-defining rib sections  418 ,  420   a , and  422   a  continually present a substantially constant open area. That is to say, at virtually every instant over a given time period, the wheel  400  gives an effective through opening, which is of substantially constant area. Furthermore, owing to the preferred, differently sized openings  418 - 422 , the staggered orientation thereof, and the locations of the defining rib sections  418   a - 422   a , at no instant is there a wholly unobstructed seed flow path through the wheel  400 . As such the tendency of prior spoke-type seed metering wheels to cause a buildup of seed, followed by presentation of a completely unobstructed seed flow path with consequent surging or “dumping” of seed, is substantially eliminated. The presence of the stationary brushes  392  and  394  assists in the desirable operation of the metering wheel  400 , by acting as a leveling device in order to successively level the upper surfaces of quantities of seeds retained by the ring  408 , so that substantially constant seed weights are present at the inlet face of the metering wheel  400 . Consequently, the seed metering wheel assembly  312  of the invention provides a substantially constant weight and volumetric flow of seed to the downstream seed treater. 
         [0097]    Turning to  FIGS. 33-40 , an alternate seed metering wheel  500  is depicted. The wheel  500  has a different design as compared with the previously described seed metering wheel  400 , and is configured for use within the overall seed metering assembly  322 . The wheel  500  is a simpler design which can be manufactured at a lower cost as compared with wheel  400 . 
         [0098]    In particular, the wheel  500  is of composite design, comprising upper and lower, interconnected, synthetic resin wheel plates  502  and  504 . The interconnected plates  502 ,  504  cooperatively define a central hub  506  having a hexagonal drive opening  508  therethrough. As illustrated in  FIG. 33 , a rotatable drive shaft  510 , identical with previously described shaft  424 , extends into the opening  508  in order to rotate wheel  500  by means of motor  364  and gear box  366 . To this end, a hub plate  512  also forms a part of the drive assembly for the wheel  500 . 
         [0099]    The overall wheel  500  includes an outermost rim  514 , a total of eight elongated ribs  516  which extend from central hub  506  to rim  514 , and a circular reinforcing ring  518  between hub  506  and rim  514 . It will be observed that the ribs  516  lie along respective, non-diameter chord lines  520  ( FIG. 34 ) which are equally spaced about the wheel  500 . In this fashion, the wheel  500  presents a series of eight somewhat triangular inner openings  522  between central hub  506  and reinforcing ring  518 , and eight larger, generally quadrate openings  524 , each outboard of an opening  522  and located between ring  518  and rim  514 . 
         [0100]    In more detail, it will be seen that plates  502  and  504  are in face-to-face contact, and are interconnected by means of screws  526 . As best illustrated in  FIGS. 36-39 , the lower wheel plate  504  has a reduced thickness downwardly extending circular contact lip  528  forming a part of rim  514 ; likewise, the lower extents of the ribs  516  are of reduced thickness. Stated otherwise, the thickness of the lower edge of the lower plate  504  i thinner than the thickness of the upper edge of the upper plate  502 . These features serve to reduce the fiction between the wheel  500  and the underlying structure of assembly  322 , while also providing sufficient mechanical strength for the wheel. 
         [0101]    As explained previously, the wheel  500  is an alternate design, which is fully compatible with the components of assembly  322 . This is best illustrated in  FIG. 40 , which depicts the weldmemts  371  defining the through-openings  396 ,  398  serving as seed entrance openings for the wheel  500 . 
         [0102]    The operation of wheel  500  is exactly as previously described in connection with wheel  400 . At virtually every instant over a given period of time, the wheel  500  presents effective through-openings of substantially constant area, and in no instance is there a wholly unobstructed seed flow path through the wheel  500 . 
         [0103]    An alternate seed metering assembly  3  is identical with the above-described structure, except that the seed metering wheel assembly  12  is eliminated and a rotary gate assembly  600  is positioned between assemblies  2  and  4  ( FIGS. 29-32 ). 
         [0104]    While the seed wheels  400  and  500  have been described in detail above, it should be understood that the system  1  can accommodate virtually any type of seed wheel. For example, USC, LLC of Sabetha, Kans. has heretofore made and sold a conventional eight-pocket seed wheel design, which can be used in lieu of the wheels  400  or  500 . That is, such a conventional wheel may be directly used with the assemblies  312  and  320 , so long as the control assembly  6  is appropriately configured. 
         [0105]    The assembly  600  includes box-like support structure  602  having a lever lock  604  permitting interconnection between the underside of assembly  600 , and the inlet of the seed treater atomizer. A circular outer wall  606  extends upwardly from support structure  602  and includes three circumferentially spaced apart oblique cam slots  608 . A rotatable gate  610 , provided with an outwardly extending circular flange  612 , is provided inboard of the wall  606  and is designed to move between a fully closed position of  FIG. 29  to an open position wherein seed will flow through the assembly  600 . An internal diverter assembly  614  is located within the confines of gate  610 , including a lower, substantially conical seed diverter  616  and upper diverter cross walls  618 . 
         [0106]    A piston and cylinder actuator  620  is positioned outboard of the gate  610  and includes a reciprocal piston rod  622  having an endmost clevis  624 . The clevis  624  is operatively connected to flange  612 , as best seen in  FIG. 32 . Three cam bushings (not shown) are secured to gate  610  and are respectively located within a cam slot  608 . When it is desired to open the assembly  600 , the actuator  620  is energized to extend the rod  622 . This serves to rotate the gate  610  the desired extent, with the cam bushings riding within the slots  608 . Such gate rotation creates a gap below the gate  610  to permit seed flow. It will be appreciated that the diverter assembly  614  serves to divide and divert down-coming seeds outwardly towards the circular gap created on rotation of gate  610 . 
       Assembly  5 —Liquid Treatment Delivery Assembly 
       [0107]    Turning now to  FIGS. 41-42 , a liquid treatment delivery assembly  5  is shown, in the form of a self-contained pump stand  710 . The stand  710  broadly includes a supporting frame assembly  712 , a tank assembly  714 , a first valve and conduit assembly  716 , a pump and conduit assembly  718 , a second valve and conduit assembly  720  with an in-line flow meter  722 , a calibration tube  724 , and control assembly  726 . The pump stand  710  is designed to bold liquid chemical(s), typically used for seed coating, and to deliver calibrated amounts of the chemical(s) to a seed treater or the like. The pump stand  710  is completely self-contained, and has a number of features greatly facilitating accurate dispensing of chemical(s). 
         [0108]    In more detail, the frame assembly  712  includes a box-like, quadrate base  728  presenting an uppermost mounting plate  730  and having a pair of upstanding, opposed frame arms  732  and  734  secured to the rear end of base  728 . An equipment mount plate  736  extends between the arms  732 ,  734 , and an uppermost rigidifying cross-brace  738  interconnects the arms  732 ,  734  at their uppermost ends. A generally U-shaped bumper  740  is secured to the anus  732 ,  734  and extends rearwardly therefrom. 
         [0109]    The tank assembly  714  includes a triangular tank base  742  comprising three upstanding legs  744  secured to the mounting plate  730  with a generally triangular, intermediate apertured support plate  746  secured to the legs  744  above mounting plate  730 . The upper end of the base  742  includes the generally circular hoop  748  likewise supported by the legs  744  adjacent the upper ends thereof. The base  742  is designed to support a conical-bottom liquid tank  750  including a generally circular upper wall  752  and a substantially frustoconical lower wall  754  having a lowermost liquid outlet  756 . An upper tank cover  758  is positioned atop the circular wall  752  in order to close the tank  750  and to allow filling thereof through the ports  760 . The cover  758  also supports an agitator drive motor  762  with an associated gear box  764 . A central agitator shaft (not shown) is operably coupled with gear box  764  and extends into the confines of tank  750 . The agitator shaft has conventional mixing elements so that the chemical(s) within tank  750  may be agitated to ensure proper mixing thereof. 
         [0110]    The first valve and conduit assembly  716  includes a delivery pipe  766  operably coupled with tank outlet  756  and equipped with a diverter valve  768 . The output end of pipe  766  is equipped with a tee  770 . A drain conduit  772  is secured to one end of the tee  770 , whereas a liquid delivery conduit  774  is secured to the opposite end of tee  770 . The drain conduit  772  is also equipped with a two-way diverter valve  776 . The assembly  716  also includes a two-way diverter valve  778  supported on a forwardly extending plate  780 . The delivery conduit  774  is secured to the input of valve  778 . A pair of output conduits  782  and  784  are also coupled with valve  778 . Output conduit  782  extends to and is coupled with calibration tube  724 , whereas output conduit  784  extends to and is connected with a liquid filter  786  secured to the rear face of mounting plate  736 . 
         [0111]    The pump and conduit assembly  718  includes a lower manifold block  788  secured to the rear face of equipment mounting plate  736 , an intermediate pumping assembly  790 , and an upper manifold block  792 . The filter  786  is coupled to lower manifold block  788  for delivery of filtered chemicals to a pair of outputs  796 , each equipped with a short conduit  798 . The intermediate pumping assembly  790  includes an electrical drive motor  800  and a pair of pumping heads  802  and  804 . The output of the head  804  is delivered through short conduits  806  to upper manifold block  792 , which delivers the pumped liquid through output pipe  808  equipped with an upstanding turbulence-minimizing pipe  810 . 
         [0112]    The second valve and conduit assembly  720  includes a liquid conduit  812  coupled with the end of pipe  808  and equipped with the in-line flow meter  722 , and a dual valve assembly  814  mounted on an upstanding plate  816  and having upper and lower valves  818  and  820 . The upper end of conduit  812  is coupled with the lower valve  820 , and the outputs thereof are respectively coupled with a coiled liquid delivery line  822 , which is coupled to a downstream seed treater or other device, and to the input of upper valve  818 . The outputs of valve  818  are respectively coupled with a recirculation conduit  824  leading to tank  750 , and a calibration tube conduit  826 . 
         [0113]    The calibration tube is in the form of an elongated upright tube  827  equipped with upper and lower end caps  828  and  830 , and a volumetric scale (not shown) imprinted on the body of the tube  827 . As illustrated, the conduit  826  is secured to the upper end cap  828 , whereas output conduit  782  is secured to lower end cap  830 . 
         [0114]    The control assembly  726  includes a conventional electrical junction box  832  coupled with control assembly  6 . Such may be though a direct connection to control assembly  6  or to a dedicated digital controller  834  equipped with a touch pad output  836  forming a part of assembly  6 . The sequential operation of the pump stand  710  is governed and controlled by the controller  834 , and this operation will be described in detail in connection with  FIG. 43 . 
         [0115]    In the preferred form of the pump stand  710 , a lowermost weigh scale  729  is used (or the mounting plate  730  is replaced with a weight scale) in order to provide continuous monitoring of the weight of chemical(s) within the tank. 
       Operation of the Pump Stand  710   
       [0116]    There are four basic modes of operation for the pump stand  710 , namely initial recirculation of liquid, pump calibration, normal calibrated delivery of liquids to the downstream seed treater or other device, and a reverse or flush operation. 
         [0117]    The recirculation mode would typically be used during startup of the system  1  in order to ensure that the liquid chemicals within the tank  750  are uniformly mixed. In order to recirculate, the agitation drive motor is operated to mix the chemicals within tank  750 . Also, the valve  768  is open to prevent delivery of liquid through outlet  756  and pipe  766 , the valve  776  is closed, and the valve  778  is opened to deliver liquid through filter  786 , lower manifold block  788 , and pumping heads  802 ,  804 . The lower valve  820  is set to deliver the pumped liquid to upper valve  888 , which is set to deliver through recirculation conduit  824 , back to tank  750 . It will thus be seen that operation of the pump assembly  790  draws liquid from the tank  750  and ultimately recirculates this fluid back to the tank. 
         [0118]    After adequate circulation is achieved, the stand  710  may be used if needed to calibrate the flow rate of the pumping assembly  790  in order to deliver consistent volumes of liquid per unit time through the delivery line  822 . Specifically, in this mode of operation, the upper valve  818  is positioned so as to deliver liquid through the calibration tube conduit  826 . This continues for a predetermined period of time (e,g., one minute), and the amount of liquid collected with calibration tube  724  is determined using the volumetric scale markings on tube  827 . If the target output of the pumping assembly  790  is 50 ounces/minute, this can be determined using the collected amount of liquid. If the flow rate is either too high or too low relative to the desired output rate, the controller  834  can be operated to compensate for the difference. In this operation, the touch screen is tapped until a calibration screen appears, whereupon the underage or overage flow rate is adjusted to the target rate. The controller  834  thus provides a signal u(t) to the pumping assembly  790  to speed up or slow down, as the case may be, so as to deliver a consistent flow rate output to the downstream seed treater or the like. The controller  834  is also provided with continuous flow rate data owing to the presence of the in-line flow meter  722 . Once calibration is achieved, the valve  778  is manipulated so that the pumping assembly  790  removes the liquid from the calibration tube  724 , which is diverted through the pumping assembly  790 , as described previously. 
         [0119]    After optional calibration, the pump stand  710  is typically used in a normal delivery mode. This requires only that the valve  778  be manipulated after emptying of the calibration tube  724  so that the pumping assembly  790  draws liquid from the tank  750 , and manipulation of lower valve  820  so that the pumped liquid is directed to the delivery line  822  for downstream use. 
         [0120]    At the end of a given run, it may be necessary to change the liquid chemical(s) within tank  750  in order to deliver different chemical(s) for a subsequent run. In such a case, the valve  776  is opened to deliver liquid to the drain conduit  772 , and the pump drive motor  800  is reversed. This serves to remove all liquids within the pump assembly and other conduits, while the material remaining in tank  750  is allowed to flow by gravitation through the conduit  772 . 
         [0121]    Before a fresh batch of liquid chemical(s) is delivered to tank  750 , it may be desirable to flush the entire system. Water or other cleaning fluids are directed to tank  750 , whereupon the pump stand  710  is operated in recirculation mode, as described above, followed by a second flush operation. The tank  750  can then be refilled with the necessary liquid chemical(s) for the subsequent run. 
       Automated Control of Pump Stand  710   
       [0122]    As mentioned above, the controller  834  governs operation of the pump stand  710  in conjunction with the overall control assembly  6 . The controller  834  is preferably an electronic integrated circuit and may be a general use, commercial off-the-shelf computer processor, a programmable logic device configured for operation with the pump stand  710 , or an application specific integrated circuit (ASIC) especially manufactured for use with the pump stand  710 . The controller  834  may include two or more separate integrated circuits cooperating to control operation of the pump stand  710 , and may include one or more analog elements operating in concert with or in addition to the electronic circuit or circuits. The controller  834  may include or communicate with a memory element configured to store data, instructions, or both for use by the controller  834 . The controller  834  is also referred to herein as a programmable logic controller or PLC. 
         [0123]    An exemplary sequence of control steps performed by the controller  834  is illustrated in the flow diagram of  FIG. 43 , which is used when the liquid coating delivery system  5  is operated either in the Flow Rate Metering Mode or in the Combined Mode illustrated in  FIG. 2B . In such instances, the  FIG. 43  control routine is used in a repeating loop to maximize the accuracy of the assembly  5 . Operation of the controller  834  may begin manually in response to a user input or automatically in response to a start signal received from an external device such as a seed treater. A user may manually launch a treatment application process by engaging a button or other user interface element designated for that purpose, as depicted in block  900 , or may place the controller  834  in automatic start mode, as depicted in block  902 . When the controller  834  is in the automatic start mode it automatically launches the process upon receiving the start signal, as indicated in block  904 . 
         [0124]    Whether the controller  834  begins the process in response to a manual input from a user or in response to a start signal, it first determines a mode of operation, as depicted in block  906 . The controller  834  may determine the mode of operation by, for example, prompting the user to select the mode or by retrieving a previously-stored setting indicating the mode of operation. If a pump percentage mode is selected, as depicted in block  908 , the controller  834  prompts the user to enter a desired percentage, as depicted in block  910 , corresponding to a percentage of the maximum output or speed of the motor. The controller  834  then communicates the control signal u(t) to the pump motor to cause the pump motor to operate at the desired percentage, as depicted in block  912 , until the user stops the motor. The pump percentage mode may be used, for example, during initial recirculation, while the target rate mode may be used during pump calibration and normal calibrated delivery. 
         [0125]    If the controller  834  operates in the target rate mode  914  the controller  834  determines a flow rate setpoint, as depicted in block  916 . The flow rate setpoint is the desired or target application flow rate. The controller  834  may prompt the user to submit the setpoint, for example, or may retrieve it from memory or receive it from an external device. The flow rate setpoint may change during operation, as explained below. 
         [0126]    When the controller  834  has determined the flow rate setpoint, it then controls the pump motor to apply treatment as closely as possible to the setpoint. More specifically, the controller  834  determines a flow rate error e(t) corresponding to a difference between the actual flow rate (as indicated by the in-line flow meter  722 ) and the setpoint and uses a feedback control loop function to modify the actual flow rate to minimize the error. The value of e(t) may be expressed in various ways, including as a raw difference or as a percentage of the setpoint. The controller  834  applies a feedback control loop to control the pump motor according to a tiered control scheme wherein a more aggressive (faster) response is applied to greater values of e(t) and a more conservative (slower and more stable) response is applied to smaller values of e(t). More particularly, the controller  834  uses a multi-tiered proportional-integral-derivative (“PID”) or proportional-integral (“PI”) control loop to manipulate process control inputs (e.g., a motor control signal) to minimize e(t). In some embodiments, the controller  834  generates a pump motor control signal according to the following control equation: 
         [0000]    
       
         
           
             
               u 
                
               
                 ( 
                 t 
                 ) 
               
             
             = 
             
               
                 
                   K 
                   p 
                 
                  
                 
                   [ 
                   
                     
                       e 
                        
                       
                         ( 
                         t 
                         ) 
                       
                     
                     + 
                     
                       
                         1 
                         
                           T 
                           n 
                         
                       
                        
                       
                         
                           ∫ 
                           0 
                           t 
                         
                          
                         
                           
                             e 
                              
                             
                               ( 
                               τ 
                               ) 
                             
                           
                            
                           
                              
                             
                               ( 
                               τ 
                               ) 
                             
                           
                         
                       
                     
                     + 
                     
                       
                         T 
                         v 
                       
                        
                       
                          
                         
                            
                           t 
                         
                       
                        
                       
                         e 
                          
                         
                           ( 
                           t 
                           ) 
                         
                       
                     
                   
                   ] 
                 
               
               + 
               
                 U 
                 Offset 
               
             
           
         
       
     
         [0000]    wherein 
         [0127]    u(t) is the pump motor control signal; 
         [0128]    e(t) is the error function defined above; 
         [0129]    K p  is a proportional coefficient; 
         [0130]    T n  is an integral coefficient; 
         [0131]    T v  is a derivative coefficient; and 
         [0132]    U Offset  is an offset variable for the motor control signal. 
         [0133]    The controller  834  is configured to manipulate the values of K p , T n  and T v  to shift the PID control function between a more aggressive response and a more conservative response. Generally, increasing the value of K p  increases the aggressiveness of the control loop while increasing the value of T n  decreases the aggressiveness of the control loop. The values of K p  and T n  will depend on other, implementation-specific variables such as the number of pump heads associated with the pump motor. The value of U Offset  may be specific to particular application chemicals and/or particular application processes. 
         [0134]    In one preferred embodiment, the variable is set to zero to entirely eliminate the derivative term from the equation such that the controller  834  implements a PI control function. Alternatively, the value of T v  may be set to a very low number to minimize the influence of the derivative term on the output. By way of example, for aggressive operation, the value of K p  may be within the range of from about 0.8 to about 0.5, for moderate operation may be within the range of from about 0.05 to about 0.2, and for conservative operation may be within the range of from about 0.02 to about 0.5. For aggressive operation, the value of T n may be within the range of from about 1.0 to about 4.0, for moderate operation may be within the range of from about 2.0 to about 5.0, and for conservative operation may be within the range of from about 4.0 to about 6.0. Table 1 illustrates exemplary values of K p  and T n  for aggressive, moderate and conservative loops when the pump motor is driving one pump head, two pump heads and three pump heads. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 1 Pump Head 
                 2 Pump Heads 
                 3 Pump Heads 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Aggressive Loop 
                 K p  = 0.2 
                 K p  = 0.15 
                 K p  = 0.1 
               
               
                   
                 T n  = 2.0 
                 T n  = 2.5 
                 T n  = 3.0 
               
               
                 Moderate Loop 
                 K p  = 0.1 
                 K p  = 0.085 
                 K p  = 0.075 
               
               
                   
                 T n  = 3.0 
                 T n  = 3.5 
                 T n  = 4.0 
               
               
                 Conservative Loop 
                 K p  = 0.01 
                 K p  = 0.01 
                 K p  = 0.01 
               
               
                   
                 T n  = 5.0 
                 T n  = 5.0 
                 T n  = 5.0 
               
               
                   
               
             
          
         
       
     
         [0135]    Returning again to  FIG. 43 , the controller  834  begins operation by entering the aggressive control loop and communicating the control signal u(t) to the pump motor, as depicted in block  918 . The controller  834  periodically compares the actual flow rate with the setpoint to determine if e(t) has fallen below an aggressive threshold, as depicted in block  920 . The aggressive threshold may be, for example, between about 20% and about 40%, and may particularly be about 25%, about 30% or about 35%. If the actual flow rate has fallen below the aggressive threshold, the controller  834  shifts to the moderate control loop and continues communicating the control signal u(t) to the pump motor, as depicted in block  922 . The controller  834  periodically compares the actual flow rate with the setpoint to determine if e(t) has fallen below a moderate threshold, as depicted in block  924 . The moderate threshold may be, for example, between about 10% and about 20%, and may particularly be about 12%, about 15% or about 18%. If e(t) has fallen below the moderate threshold, the controller  834  shifts to the conservative control loop and continues communicating the control signal u(t) to the pump motor, as depicted in block  926 . If e(t) has not fallen below the moderate threshold, the controller  834  returns to block  920  to determine if e(t) is below the aggressive threshold. 
         [0136]    When the controller  834  is operating in the conservative control loop, it remains in the conservative control loop until the user presses a stop button, until the setpoint changes as depicted in block  928 , or until e(t) exceeds the moderate threshold. If the setpoint changes the controller  834  shifts back into the aggressive control loop to bring the actual flow rate near the setpoint as quickly as possible, then shifts back into the moderate and conservative control loops as e(t) decreases, as explained above. 
         [0137]    The user may initiate the reverse or flush operation set forth above by engaging a button or other user interface element designated for that purpose, as depicted in block  930 , wherein the controller  834  drives the pump motor in reverse, as depicted in block  932 . The controller  834  continues driving the pump motor in reverse until the user presses a stop button. 
         [0138]    The controller  834  may store operational parameters associated with particular chemical mixtures and/or particular processes so that when a user reinitiates a process that was previously run the controller  834  recalls the parameters associated with that process, thus relieving the user of the burden of re-calibrating the pump stand  710  each time a process is run. Using the touch pad  836 , for example, the user may calibrate the pump stand  710  for use with a first chemical mixture. First calibration information specific to the first chemical mixture is created and used, for example, to adjust the output of the flow meter  722 . The controller  834  stores the first calibration information in the memory. When the pump stand  710  is subsequently used with a different process that involves a second chemical mixture the user calibrates the pump stand  710  for the second mixture. The controller  834  associates second calibration information with the second mixture and stores the second calibration information in memory. This process may be repeated for multiple chemical mixtures, wherein the controller  834  stores separate calibration information for each of the chemical mixtures. 
         [0139]    Thereafter, each time the user desires to use the first chemical mixture he or she simply selects the first mixture via the touch pad  836  wherein the controller  834  retrieves the first calibration information from memory. In this manner, the controller  834  may retrieve and use operational parameters associated with any of the previously used chemical mixtures. While the discussion above has focused on the use of calibration information used to adjust the output of the flow meter  722 , the operational parameters stored in memory and retrieved by the controller  834  may also be associated with any of the variables K p , T n , T v , U Offset . 
         [0140]    While the use of a self-contained pump stand  710  with its own logic controller  834  is preferred, the invention is not limited to such stands. For example, the system  1  can operate pump stands that do not include separate controllers and, in such cases, all calculations will be performed by the assembly  6 . In one such scenario, the system can operate a liquid treatment delivery assembly equipped with a liquid weigh scale by monitoring and controlling liquid flow rates via declining mass techniques. In such a case, use is made of a pump having a predetermined equation to operate at a certain speed when pump operation is initiated. After a short period (such as 8-25 seconds), the assembly  6  compares the weigh scale&#39;s total loss in mass to its predicted loss in mass (determined by the preset flow rate and the density of the liquid) and adjusts the pump speed accordingly. In addition, the assembly  6  may operate the pump to adjust the speed thereof to accommodate accumulated inaccuracies created during earlier phases of the seed coating run. This additional correctional capability is available when using the decreasing mass mode, or the combination mode of operation. 
       Alternate Assembly  1  Using a Single Batch Hopper 
       [0141]    Turning to  FIGS. 44-45 , a seed bin assembly  1000  is depicted in  FIG. 4  and broadly includes a single batch, decreasing mass seed hopper or bin  1002  situated above the previously described seed metering assembly  3  and seed treater assembly  4 . Thus, the overall structure of system  1000  is identical with that illustrated and described in connection with  FIGS. 3-39 , except that the multiple-bin hopper assembly  24  has been replaced by the hopper  1002 . Accordingly, a detailed description of the assemblies  3  and  4  need not be repeated. 
         [0142]    The seed hopper  1002  includes an upper tubular section  1004  and a lowermost frustoconical section  1006  leading to a central outlet opening (not shown). The lower outlet opening is equipped with a principal slide gate assembly  1008 , which is identical with the previously described assembly  112 . The assembly  1008  is designed to selectively regulate the flow of seed from the outlet opening, as previously mentioned. In addition, a manually operated secondary slide gate assembly  1010  is provided beneath the assembly  108 . This assembly is operated by means of a manual crank  1012 , and is used for manual flow control if the hopper  1002  is used for feeding a conveyor or the like; therefore, this secondary assembly  1010  is not generally used in the context of the present invention. A tubular outlet pipe  1014  is situated beneath the slide gate assemblies  1008  and  1010 , and is designed to deliver seed directly into the confines of seed metering assembly  3 , as is readily apparent from a consideration of  FIG. 44 . The hopper  1002  is supported by a frame assembly  1016  having four upright legs  1018  secured to the hopper  1002 , and which are in turn supported by a lower square box frame  1020 . The four corners of the frame  1020  are equipped with load cells  1022 . 
         [0143]    The operation of assembly  1000  is identical to that described in connection with system  1 , except that it is a batch system rather than a batch-continuous system. 
       Control Assembly  6   
       [0144]    The overall operation of system  1 , using either the multiple-bin apparatus  20  or single bin assembly  1000 , relies upon inputs and outputs to the control assembly  6 . In general, inputs to the control assembly  6  from the seed bin assembly  24  or  1002  include the weight of seed within the bin(s), as reported by the load cells  78  or  1022 , and the status (open or closed) of the discharge devices  112  and  1008  as reported by the gate sensors. The outputs to the seed bin assembly  24  or  1002  include instructions to open or close the associated discharge devices  112  or  1008 . 
         [0145]    The inputs to the control assembly  6  from the seed metering wheel assembly  3  include the rotational speed of the seed wheel and the status of the proximity sensors  388  and  390 , which confirm the presence or absence of seed. The output to the seed metering wheel assembly  3  is the control of the VFD (variable frequency device) couple with seed wheel motor  364 . 
         [0146]    The inputs to the control assembly  6  from the coating apparatus  4  are the operational speeds of the atomizer  314  and drum  316 , whereas the outputs are atomizer and drum VFD control. 
         [0147]    Finally, the inputs to the control assembly  6  from the liquid coating delivery assembly  5  are the rate of pump  800 , the flow rate reported by meter  722 , the status of the valve  768 , and the weight of liquid within the tank as reported by scale  729 . The outputs include the control of the speed of the pump  800  and the position of the valve  768 . 
         [0148]    Referring to  FIG. 2A , it will be noted that the seed bin assembly  24  can be operated in three alternate modes. Considering first the decreasing mass mode, the operator would first select this mode using the control assembly  6 . This mode requires no calibration before the run begins, and the system will automatically and continuously self-calibrate during the seed-treating run. The system in this mode uses only the scale data derived from the load cells  78  or  1022 , and requires no post-treatment calibration owing to the continuous self-calibration. 
         [0149]    In the seed-metering mode, the operator again initiates this mode through the control assembly  6 . Here the quantity of seeds is comprised of a plurality of subquantities of seeds. This system requires a “cup weight” calibration reading to be entered before seed flow begins, and a seed profile to be selected. Such cup weights are used to perform an initial “rough” calibration until further data is collected for calibration during the course of the treatment run. The system employs both the selected seed profile calibration data and the cup weight to calculate the seed flow rate and the total amount of seed treated. After completion of the treatment run, the operator can enter the known weight of the seed (usually found on the seed box label or scale data) into the calibration screen of the control assembly  6 , to provide a further calibration of the seed profile. 
         [0150]    In the combined mode, both the decreasing mass and seed metering modes are used, and again the combined mode is entered by the operator into the control assembly  6 . This mode requires no calibration before the run begins, because the system will automatically calibrate itself during the run by comparing the seed wheel totalizer data to the decreasing mass totalizer data, followed by recalculating the seed profile calibration data. During the course of the run, the system uses both the selected seed profile calibration data and the cup or other subquantity weight to calculate the seed totalizer and flow rate. This system requires no calibration after completion of the treatment run, because the system automatically calibrates itself during the course of the run, as indicated previously. 
         [0151]    Now referring to  FIG. 2B , the three alternate modes of operation are depicted. In the use of the decreasing mass mode, the operator inputs the selected mode into the control assembly  6 . The system requires only a density factor for the selected coating liquid before liquid flow begins, as well as a weigh scale, such as the scale  729 . During liquid flow, the system uses the density data and scale readings to calculate the liquid totalizer and flow rate. Post-run calibration of the density data can be done via mass balancing, by comparing the totalizer results to the actual weight of the liquid which was used during the run. 
         [0152]    In the flow rate metering mode, the system only employs the in-line flow meter  722 . The system requires a calibration be done for each treating liquid before the seed treatment begins. This is accomplished as explained above in connection with the pump stand  710 . During the treatment run, the system uses the calibration data and the flow meter readings to calibrate the liquid totalizer and flow rate. No post-run calibration is available. 
         [0153]    In the combined mode, the scale  729  and flow meter  722  are used Again, the operator initiates this mode at control assembly  6 , by an appropriate input. The system requires no calibration before the treatment run begins, because the system automatically calibrates itself during the flow of liquid by comparing the flow meter totalizer to the decreasing mass totalizer and then recalculating the calibration data. During the seed treatment, the system uses both the liquid calibration data and the flow meter readings to calculate liquid totalizer and liquid flow rate. Post-run calibration can be accomplished via mass balancing by comparing the totalizer results to the actual weight of the liquid which was used. 
         [0154]    It will thus be seen that in both the seed bin and liquid coating delivery assemblies, system flexibility is paramount. That is, the operator can run the seed bin assembly in any mode, independent of the mode selected for the liquid coating delivery assembly. This allows for maximum flexibility of operation when service needs arise. It is particularly preferred that the combined modes of operation of the assemblies be used, because this makes use of the strengths of the decreasing mass and metering modes. That is, the seed metering mode gives essentially instant results and is mechanically robust; however, this mode, based upon calibration settings, is not as repeatable or as accurate as the decreasing mass modes. The latter are highly accurate, and self-calibrating, but are relatively slow and sensitive to environmental problems (e.g., accidental contact or upset of a scale). Therefore, the combined modes are deemed optimum. 
         [0155]    Another advantage of the control assembly  6  is that it is designed to accommodate multiple different profiles pertaining to individual seeds and coating liquids previously run on the system  1 . Thus, the controller will store in memory seed profiles for particular types of seeds and seed wheel setups, and also the operational parameters associated with particular treating liquids and flow rates. Then, when the same seeds and/or coating liquids are used, the system can call up these stored values to facilitate initial settings and calibrations of the seed treating, equipment. 
       Alternate Pump Stands 
       [0156]    Turning first to  FIGS. 46-47 , a pump stand  1100  may be used in lieu of the stand  710  previously described. Broadly speaking, the stand  1100  includes a weigh-scale base  1102 , a conical liquid tank  1104  supported on the base  1102 , and an upstanding component frame  1106  designed to support many of the operational components of the stand  1100 . 
         [0157]    In more detail, the base  1102  includes a bottom plate  1108  and a shiftable weigh plate  1110 . The output of base  1102  is operatively connected with controller  6  to continuously provide weight data during the operation of the system  1 . 
         [0158]    The tank  1104  includes an uppermost, generally cylindrical section  1112  surmounted by a top cover  1114 . A lowermost conical section  1116  extends below the section  1112  and terminates in a tubular outlet  1118 . The tank  1104  is supported by three upright legs  1120 , which are secured to the plate  1110 . An apertured, generally triangular reinforcing plate  1122  is secured to the legs  1120  as illustrated. The outlet  1118  is equipped with an on-off valve  1124  leading to a tee  1126  and a secondary on-off valve  1128 . A drain hose  1130  is secured to the outlet of valve  1128 . 
         [0159]    The component frame  1106  includes upstanding legs  1144 , each equipped with a base  1146 . A cross-frame plate  1148  extends between and is secured to the upper ends of the legs  1144 . The plate  1148  supports a series of components used to control the operation of the stand  1100 . Specifically, the plate  1148  supports a primary three-way valve  1150 , a secondary three-way valve  1152 , a calibration tube  1154 , a flow meter  1156  ( FIG. 47 ), a filter  1157  having an inlet  1157   a  and an outlet  1157   b , and a peristaltic pump  1158 . 
         [0160]    A suction line  1160  extends from the end of the tee  1126  remote from valve  1128  and is connected to filter inlet  1157   a . A line  1164  extends from the filter outlet  1157   b  to pump  1158 . The outlet of pump  1158  passes through line  1166  to the inlet of flow meter  1156 ; the line  1160  is equipped with a pulse dampener  1168  as shown. A line  1170  extends from the outlet of flow meter  1156  to the inlet of valve  1150 . One output line  1172  of the valve  150  is designed to be coupled with seed treater assembly  14 . Another valve line  1174  extends from an outlet of valve  1150  to the inlet of secondary valve  1152 . One outlet of valve  1152  is coupled with calibration tube  1154 , whereas the other outlet is connected to a recirculation line  1176  back to tank  1104 . 
         [0161]    Again referring to  FIG. 46 , it will be seen that the cover  1114  supports and agitator motor  1178 . A downwardly extending agitator shaft (not shown) extends into the confines of tank  1104  for agitating the contents thereof. 
         [0162]    As described in connection with the stand  710 , the stand  1100  has four modes of operation, namely recirculation, pump calibrations, normal calibrated delivery of liquids to the coater apparatus, and a reverse or flush operation. 
         [0163]    During initial recirculation, the liquids are agitated via motor  1178 , and the pump  1158  is operating. The valves  1150  and  1152  are manipulated so that liquid passes through the valves for return to the tank via line after adequate circulation and mixing is achieved, the pump may be calibrated in order to deliver consistent volumes of liquid per unit time through the pump outlet line  1166 . In this mode, the valve  1152  is manipulated to deliver liquid to calibration tube  1154  for a predetermined period of time. Then, using the calibrations associated with tube  1154 , the amount of liquid per unit time can be calculated. 
         [0164]    After optional calibration, the stand  1100  is typically used in a normal delivery mode. This requires appropriate manipulation of the valves  1150  and  1152  so that liquid passing from pump  1158  and through flow meter  1156  is directed through outlet line  1172 . Of course, the output of flow meter  1156  is operatively coupled with controller  6 , as previously described. 
         [0165]    At the end of a given run, it may be necessary to change the liquid within tank  1104  in order to deliver different liquids for a subsequent run. In such a case, the valve  1124  is operated to deliver fluid to the secondary valve  1128 , and the latter is opened to deliver liquid to drain conduit  1130 , and the bulk of the liquid within tank  1104  drains by gravitation for disposal. 
         [0166]      FIGS. 48 and 49  illustrate a pump stand  1200 , which is similar in many respects to the stand  1100  and, where identical components are present, like reference numerals are used. The principal difference between the stand  1200  and the stand  1100  is that the former is designed for use with an upright cylindrical chemical tote or keg  1202  rather than a conical tank  1104 . Again, broadly speaking, the stand  1200  includes a weigh-scale base  1102  supporting the tote  1202 , and an upstanding component frame  1106  designed to support many of the operational components of the stand  1200 . 
         [0167]    The tote  1202  does not include a lower outlet as in the case of the conical tank  1104 . Accordingly, a single outlet  1204  is provided on the top plate  1206  of the tote  1202 . A two-way valve  1208  is coupled with the outlet  1204 . A suction line  1210  extends from one port of the valve  1208  to the inlet  1157   a  of filter  1157 . A second line  1212  extends from the other port of valve  1208  to valve  1152 . The valve  1208 , together with the valves  1150  and  1152 , is appropriately manipulated during the modes of operation of stand  1200  to alternately recirculate fluid therein, to calibrate using tube  1154 , or to deliver fluid to line  1172 . Given that the tote  1202  is separable from the pump stand  1200  and is replaced as necessary, there is no back flush operation with this pump stand  1200 . 
       EXAMPLE 
       [0168]    In order to illustrate the functionality of the invention, the following hypothetical example is provided using the combined modes to control seed and coating liquid flow using the combined control modes for the seed bin(s) and liquid coating delivery assembly. 
         [0169]    In this example, 10,000 lbs of seed are treated at a rate of 1000 lbs per minute, using the system  1 . A liquid coating slurry having a density of 8 fluid oz per lb is applied to the seed at a rate of 30 oz per minute, or 3 oz per 100 lbs of seed. Initially, one of the seed bins  34  of assembly  24  has 700 lbs of seed therein, as determined by the load cells  78 , and the associated slide gate  112  is closed. The other two bins are empty, and the gates  112  thereof are closed. A cup weight to pocket volume of 2.5 is inputted to the controller  6 . The liquid tank  750  holds 500 lbs of slurry, or 4000 fl oz, as determined by the weigh scale  729  associated with stand  710 . 
         [0170]    The speeds of the drive motors for the atomizer  314  and drum  316  are set using controller assembly  6  in accordance with the desired seed coating rate, and the operation of the atomizer and drum begins. The pump stand  710  is in its recirculation mode with the valve  768  properly set for this operation, at the preselected slurry flow rate of 30 oz per minute (1,000 lbs per minute/(100 lbs)×3 oz). 
         [0171]    In order to initiate the seed coating operation, the slide gate assembly  112  of the pre-filled seed bin  34  is opened by activation of the associated piston and cylinder assembly  122 , which permits a quantity of seeds to freely gravitate into the hopper assembly  320 , through the openings  344 ,  346  and  396 ,  398  above the seed metering wheel, which in this case is the previously described eight-pocket seed wheel; the proximity sensors  388  and  390  confirm the presence of the seed. The system uses an initialized value for the cup weight, for example 3.65 lbs, which is an average cup weight for seeds not previously treated by the system. The rotation of seed wheel is begun by activation of the motor  364 . Theoretically, one revolution of the seed wheel should deliver 146 lbs of seed (3.65 lbs per cup=2.5 cups per pocket=16 delivered pockets per wheel revolution 146 lbs). The weight of seed in the bin  34  is then checked to determine the actual weight of seed delivered during the first wheel revolution, say, 450 lbs. This means that 150 lbs of seed was actually delivered, rather than the theoretically calculated 146 lbs. At this point, the control assembly  6  operates to calculate a new cup to pocket factor. The 150 lbs of actually delivered seeds is divided by the theoretical seed delivery of 146 lbs to create a correction factor of 1.0274. Then, this correction factor is multiplied by the cup to pocket factor of 2.5. This gives a new cup to pocket factor of 2.5685 cups per pocket for this seed type. During these steps, the rotation of turret  140  is begun by actuation of drive motor  180 , to begin the sequential delivery of seed to the other two, initially empty bins  34 . 
         [0172]    The cup to pocket factor is adjusted and stored in memory so that future iterations of the program will be able to incorporate a cup weight into each seed profile, which will allow the operator to perform a pre-run calibration with the cup weight specific for the seed profile. Cup weight multiplied by the cup to pocket factor equals the weight of seed in each seed wheel pocket, so that adjusting either the cup weight of cup to pocket factor will give the best result. 
         [0173]    At the same time, the valve  768  is reset to its normal calibrated delivery mode of operation, and the pumping assembly  790  is started. Accordingly, seed is delivered through the wheel and passes through atomizer  314  for coating, with ultimate drying in drum  316 . 
         [0174]    The delivery of slurry is begun using the initially selected flow rate for 10 seconds. According to the initial flow rate, 5 oz of slurry (30 oz per 60 seconds×10 seconds=5 oz) should be delivered, or 0.625 lbs (5 oz slurry 8 oz per lb 0.625 lbs). The actual slur flow rate is determined as compared with the initially selected flow rate. This is done by reading the pump stand scale output and then calculating the actual flow rate. For example, if the scale reading is 499.5 lbs after 10 seconds, only 4.5 lbs of slurry has been actually delivered, versus the 5 lbs predicted by the initial setting. Thereupon, the flow meter  722  is re-calibrated by dividing 0.625 lbs by 0.5 lbs, giving a correction factor of 1.25. This factor is multiplied by the chemical profile&#39;s calibration factor, which is assumed to be 1 to give a new chemical calibration factor of 1.25. The control assembly  6  then operates to speed up the flow of liquid until the flow meter reports a flow rate of 37.5 oz per minutes (30 oz per minute×1.25=37.5 oz per minute). The output of the control assembly will report the desired flow rate of 30 oz per minute by using the flow meter reading of 37.5 oz per minute and dividing it by the 1.25 correction factor. 
         [0175]    The seed flow rate and liquid flow rate are periodically re-calibrated during the seed treatment run to ensure the most accurate results. The system  1  is then fully calibrated and the cup weight and flow meter correction factors are stored in system memory so that these can be called up and used as initial conditions when the same type of seed is treated in the system  1 . 
         [0176]    A particular feature of this mode of operation is that the seed wheel and flow meter operation can be successively re-calibrated during operation, rather than only a post-operation re-calibration, as is common in the art.