Abstract:
A fast fill pump system for a self-propelled field sprayer includes high capacity centrifugal pump for tank filling. The centrifugal pump is connected in parallel with the fill connection and primed by a lower capacity diaphragm spraying pump. Two check valves and a pressure sensor allow the sprayer control to automatically control the pump priming and tank filling with the activation of one switch. The two-pump system preserves tank filling speed, even during operation of eductor or tank agitation functions. The centrifugal pump can be removed and the spraying pump operated to fill the tank without substantial base machine modification.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to self-priming fast fill pump system for an agricultural sprayer such as a self-propelled field sprayer. 
       BACKGROUND OF THE INVENTION 
       [0002]    Sprayers, particularly in Europe, are often equipped with a diaphragm spray pump. The diaphragm pump is self-priming and can load water or chemical solution from an external source even when there is no head present. Self-priming is necessary, for example, when a tank is filled with water from a ditch, canal or other source that is lower than the sprayer pump. However, such self-priming pumps typically have flow rates on the order of 74 gal/min or less. Centrifugal pumps can achieve flow rates of 150-200 gal/min but must have positive head pressure so that the inlet of the pump is flooded. Therefore, use of the higher capacity centrifugal pump presents problems in situations where the source does not provide such a head pressure. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides an auxiliary centrifugal pump to fill the sprayer, and uses the diaphragm spraying pump to prime the centrifugal pump. A unique parallel plumbing configuration effectively primes the centrifugal pump while preserving the original spraying and loading functionality of the base machine. Two check valves and a pressure sensor allow the sprayer control to automatically control the pump priming and tank filling with the activation of one switch. The parallel design also permits the auxiliary centrifugal pump to be added to a base machine with little or no disruption of original machine functionality and few hardware modifications. When the centrifugal pump is removed, the spraying pump provides the filling function. The two-pump system preserves tank filling speed, even during operation of eductor or tank agitation functions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  shows a schematic for a self-priming, fast fill sprayer system. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0005]    Referring to  FIG. 1 , therein is shown a schematic for a sprayer system  10  for a field sprayer  12 . The sprayer  12  includes sprayer nozzle sections  14  for applying material from a solution tank  16  to plants or the soil. 
         [0006]    A sprayer pump  20  (pump  1 ) is connected through a strainer  22  and a control valve  24  to an outlet  26  of the solution tank  16 . The pump  20  is a self-priming pump such as a diaphragm pump and has an outlet  28  connected through a spray regulator  30  and strainer  32  to sprayer section control valves  34 . Flow and pressure signals are provided through flow and pressure transducers  36  and  38 . 
         [0007]    The output  28  of the pump  20  is also connected to an agitation and rinse assembly  40  through a control valve  41  and to an eductor and wash brush assembly  42  through a control valve  43 . The valve  41  can be activated to direct pressurized fluid from the output  28  to agitation nozzles  45  within the solution tank  16 . The valve  43  can be activated to selectively direct pressurized fluid from the pump output  28  to a wash brush system  46  and to an eductor  48  for adding chemical to fluid directed from the valve  43  through a venture  49  and into the solution tank  16 . 
         [0008]    A bypass circuit  50  includes a bypass valve  51  connected between the regulator  30  and the pump output  28  by a line  52 . The line  52  is also connected to a selector valve  56 . The valve  56  is also connected to a solution tank input  58 . The output  28  of the pump  20  is connected through an agitation regulator  60  and a pressure responsive valve  62  to the tank input  58 . 
         [0009]    A fill system  70  is connected via line  72  to the input of the pump  22 . A quick fill valved connector  74  is connected by a line  73  and a one-way check valve  76  to the line  72 . A rinse tank  78  is connected through a one-way check valve  80  and a rinse tank valve  82  to the valve  76  downstream of the connector  74 . A rinse tank quick fill valved connector  84  provides access for filling the tank  78  from a source of rinse fluid. The solution tank  16  can be filled using the self-priming pump  20 , even from a source of fluid that lacks head pressure, by closing the spray valves  34  and directing fluid from the pump output  28  through the valve  62  to the tank input  58 . However, use of the pump  20  for solution tank filling limits pumping rate and interferes with eductor and agitation functions. 
         [0010]    To provide added fill pumping capacity while retaining the benefit of the self-priming feature, an auxiliary pump  80  is connected between the quick fill connector  74  and the line  72  in parallel with the line  73  and the check valve  76 . The pump  80 , which is shown as a high capacity centrifugal pump, includes an input  82  connected to the line  73  downstream of the connector  74 , and an output connected through a strainer  86  and a one-way check valve  88  to the line  72 . A pressure transducer  90  provides a signal indicative of the pressure in the line  72 . The pumps  20  and  80  are driven in a conventional manner, such as by variable speed hydraulic motors. 
         [0011]    A controller  100  is operably connected to the pumps  20  and  80 , the bypass valve  51  and the tank/pump selector valve  56  and receives the pressure signal from the transducer  90 . A controller switch  104  is closed to activate automatic control of solution tank filling when the connector  74  is in fluid communication with a source of fluid for the solution tank  16 . The controller  100  may be a system controller for controlling sprayer functions in addition to the filling function. For example, the controller can also receive feedback from the various flow and pressure sensors to provide spray control for the spray nozzle system. The sensor  90  provides a signal to the controller  100  indicative of the centrifugal pump output pressure, and the controller  100  adjusts centrifugal pump speed in accordance with the signal. The signal from the sensor  90  also informs that controller  100  that a head is present at the pump  80  during initialization of the quick fill function. 
         [0012]    To provide quick filling of the solution tank  16 , the connector  74  attached to the source of filling fluid, and the controller  100  is activated to provide controlled filling. The controller  100  activates the self-priming pump  20  to draw fluid through the connector and the check valve  76  into the line  72  and provide a head at the pump input  82 , even if the source of the filling fluid is below the input  82 . Once primed, the centrifugal pump  80  draws filling fluid from the source through the connector  74 . The pump  80  delivers the fluid through the strainer  86  and the check valve  88  to the line  72  and through the tank/pump selector valve  56 . The controller  100  directs the valve  56  to open the line  72  to the solution tank input  58  so that the fluid from the pump  80  is delivered to the solution tank  16 . The parallel design also permits the auxiliary centrifugal pump  80  to be added to a base machine with little or no disruption of original machine functionality and simple modification of the original plumbing. When the pump  80  is removed, the spraying pump  20  provides the filling function. 
         [0013]    The pump  20  is operable independently of the auxiliary pump  80  to provide tank agitation and eductor functions. By directing fluid from the pump output  28  through the valve  41  to the nozzles  45 , the solution in the tank  16  is agitated. To operate the eductor system, the valve  43  is turned to direct fluid through the venturi  49  and draw chemical from a container connected to the eductor  48  into the solution tank  16 . The valve  43  can be positioned to provide fluid flow to the wash brush system  46 . The regulator  60  maintains the pressure to the wash and eductor systems below a preselected level by selectively returning fluid to the tank  16  through the valve  62  and the tank input  58 . 
         [0014]    During normal sprayer operations, the valves  34  are opened, and the valve  24  opens the solution tank outlet  26  to the input of the pump  20  through the strainer  22 . The spray solution is directed through the regulator  60  to the spray regulator  30  and out to the spray sections  14  through the corresponding valves  34 . Excess solution is circulated back to the tank  16  through the valve  62  and inlet  58  and provides some agitation of the spray solution. If necessary, additional agitation can be provided during spraying operation by opening the agitation valve  41  to direct some spray solution from the pump outlet  28  to the nozzles  45 . 
         [0015]    To rinse the tank  16  between operations, a pump off valve connection  110  is opened to a storage tank (not shown), and excess solution in the tank  16  is pumped out by the pump  20 . The valve  82  is turned to open the rinse tank  78  to the input of the pump  20 . Pressurized rinse tank fluid is directed from the pump output  28  through the valve  41  and the nozzles  45  to rinse the inside walls of the tank  16 . The valve  43  can be opened to direct fluid to the wash brush system  46 . 
         [0016]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.