Patent Publication Number: US-2022219178-A1

Title: Solenoids for mobile sprayers

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of Canadian Application No. 3,106,227 entitled “SOLENOIDS FOR MOBILE SPRAYERS”, filed Jan. 14, 2021, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     This disclosure relates to the field of spraying equipment and in particular mobile sprayers for spraying a surface such as an agricultural field, golf course, roadway, or the like. 
     BACKGROUND OF THE INVENTION 
     There are many applications where it is necessary to spray a fluid material onto a target surface, often the ground. This application is notable for example in agriculture, horticulture and such things as golf course maintenance and pest control where chemicals are mixed with water and then sprayed on the ground, on plants growing from the ground, on bodies of water, and the like. Various fluids must also often be sprayed on roadways and other surfaces as well. 
     Spraying is accomplished with sprayers, either self-propelled or towed units, and with aerial sprayers mounted on airplanes or helicopters. Such sprayers commonly comprise a tank of fluid, a pump for pressurizing and distributing the fluid to spray nozzles and means to control the fluid pressure. Sprayers typically have a plurality of nozzle bodies, each securing a spray nozzle, mounted on booms which swing in for transport and out for operation. Airplane mounted sprayers typically have a boom fixed to the wings. 
     The nozzle locations are spaced apart on a boom, perpendicular to the direction of travel, at a standard spacing distance which corresponds to the spray pattern of the nozzles. The same size nozzle is in operating position at each nozzle location, providing a consistent application rate across the width of the sprayer. 
     Such sprayers must accurately dispense the fluid over the desired area of target surface. Historically this has been accomplished by providing a spray nozzle having a set operating pressure such that when operated at that pressure, the nozzle accurately dispensed a known amount of fluid per time unit. Operating the sprayer at a known speed then accurately resulted in the correct amount of fluid being dispensed over a given area, however as the speed increased or decreased the application rate increased or decreased accordingly. 
     To help overcome this problem, “extended range” nozzles were developed which maintained an accurate distribution across the width of the spray pattern at a range of pressures from approximately 20 psi to 60 psi. If the operator wants to spray at an increased or decreased speed, he increases or decreases the pressure to maintain the desired application rate. Such extended range nozzles provide satisfactory spray patterns over a range of about 30% above or below a mid-point rate, however where larger rate changes are required, a nozzle change is required. 
     Rate controllers became available as well which measure the total flow of fluid along the boom to the nozzles and automatically vary the pressure as the speed varies, maintaining a total flow to the nozzles that will maintain a stable application rate along the boom as speed varies. These rate controllers can also be used to vary the application rate by maintaining a constant speed, and varying the pressure. Variable application rates have become desirable with the advent of field mapping, where different areas of a field are best treated with different rates of the particular liquid being applied. 
     Modern agriculture/horticulture sprayers typically have a boom with multiple spray sections that can be independently controlled. Usually a master control means is used to control the entire boom, while each section may have its own control or switch. Liquid pressure in each section can be varied by a rate controller to apply different rates to field portions passed over by each section, and flow to any section can be stopped completely if desired. 
     External location and guidance systems utilizing Global Positioning Satellites (GPS), local broadcasting towers, and the like have allowed sprayers to be located and also guided precisely, and also provide precision control of application rates and avoidance of spray overlap as described for example in U.S. Pat. Nos. 6,522,948 and 6,877,675 to Benneweis. 
     U.S. Pat. No. 6,126,088 to the present inventor Wilger discloses a nozzle mounting and control system for use in sprayers comprising multiple nozzles mounted in the operating position at each nozzle location on a sprayer boom such that 2, 3, or more nozzles pass over the same target surface. Wide ranges of application rates are achieved by control valves operable to select which nozzles are open and operating at any given time. The valves may be remote controlled and may further incorporate a rate controller to maintain a chosen application rate by opening and closing appropriate valves as the sprayer speed varies, and/or by varying the pressure in the conduits supplying the nozzles. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a spraying apparatus that overcomes problems in the prior art. 
     A solenoid is one typical valve used to turn sprayer nozzles off and on to avoid overlap or change spraying rates in the prior art. In order to stop drips and seal the liquid in the sprayer these solenoids are typically configured to be “normally closed” such that when no electrical power is being applied to the coil the valves are closed, and then the valves open when electrical power is applied to the coil. 
     In mobile sprayers this can be a significant challenge to the electrical charging system of the vehicle involved, be it a tractor or a self-propelled vehicle. To keep any particular valve open, electrical power must be continuously provided, and when it is turned off, the valve closes. 
     This electrical power requirement limits the use to which solenoids can be used in mobile sprayers. The present disclosure employs latching or bistable solenoids to provide a significantly wider range of options for the use of solenoids. 
     For example as discussed above where there are three nozzles at each nozzle location it has typically been the case that switching from one combination to another was accomplished with pressurized air or manually, since maintain electrical power to one or more solenoids at each location was not practically possible. The latching solenoids of the present disclosure allow the on/off selection of each of these nozzles with a short lived pulse of electricity, with no constant electrical power required. 
     Such latching solenoids work in a different manner, in that a momentary contact with a direct current electrical source with one polarity switches it from on to off, and then another momentary contact with the DC electrical power with the opposite polarity switches it from off to on—once the latching solenoids are either off or on, there is no further electrical power required. 
     The present disclosure provides a mobile sprayer apparatus comprising a direct current electrical supply, and a supply conduit operative to supply pressurized liquid to a plurality of nozzle assemblies. Each nozzle assembly comprises a channel connecting the supply conduit to a nozzle, a valve operative to selectively open and close the channel, and a solenoid coil operative to selectively move the valve to an open position when a direct current electrical pulse is connected to pass through the solenoid coil in a first direction, and to selectively move the valve to a closed position when a direct current electrical pulse is connected to pass through the solenoid coil in an opposite second direction. A switch is connected to the direct current electrical supply and is operative to selectively deliver a pulse of electrical energy through each solenoid coil in the first direction or through each solenoid coil in the second opposite direction, and no electrical energy is delivered to the solenoid coils between pulses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where: 
         FIG. 1  is a schematic sectional side view of a dual nozzle body for use with the solenoid coils of the present disclosure; 
         FIG. 2  is a schematic side view of a switch for use with the solenoid coils of the present disclosure; 
         FIG. 3  is a schematic top view of an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIGS. 1-3  schematically illustrate an embodiment of a mobile sprayer apparatus  1  of the present disclosure comprising a supply conduit  3  operative to supply pressurized liquid to a plurality of nozzle assemblies  5 . Each nozzle assembly  5  comprises a channel  7  connecting the supply conduit  3  to a nozzle  9 , and a valve  11  operative to selectively open and close the channel  9 . 
     A solenoid coil  13  is operative to selectively move the valve  11  to an open position when a direct current electrical pulse is connected to pass through the solenoid coil  13  in a first direction D 1 , and to selectively move the valve  11  to a closed position when a direct current electrical pulse is connected to pass through the solenoid coil  13  in an opposite second direction D 2 . Each solenoid coil  13  has a first end  15 A and a second end  15 B. 
     It is contemplated that there will be many arrangements that could be used to provide the required electrical pulses in two directions through the solenoid coil  13 . To illustrates however the operation of a DPDT(double pole, double throw) Center OFF Momentary switch  17  is schematically illustrated in  FIG. 2 . The switch  17  is connected to the direct current electrical supply  19  comprising a positive (+) terminal and a negative (−) terminal and is operative to selectively deliver a pulse of electrical energy through each solenoid coil  13  in the first direction D 1  or through each solenoid coil  13  in the second opposite direction D 2  and no electrical energy is delivered to the solenoid coils  13  between pulses. To direct a pulse of electrical energy through each solenoid coil  13  in the first direction D 1 , the switch  17  connects the first end  15 A to the positive terminal of the electrical supply  19  and the second end  15 B to the negative terminal of the electrical supply  19 . 
     To direct a pulse of electrical energy through each solenoid coil  13  in the second direction D 2 , the switch  17  connects the first end  15 A to the negative terminal of the electrical supply  19  and the second end  15 B to the positive terminal of the electrical supply  19 . As shown in  FIG. 2  the switch  17  comprises a neutral position NP wherein no pulse is sent, an open position OP located on a first side of the neutral position NP, and a closed position CP located on an opposite second side of the neutral position NP. 
     When in the open valve position OP the switch  17  sends a pulse through the solenoid coil  13  in the first direction D 1  by connecting the first end  15 A of the solenoid coil  13  to the positive terminal of the electrical supply  19  and connecting the second end  15 B of the solenoid coil  13  to the negative terminal of the electrical supply  19 . 
     When in the closed valve position CP the switch  17  sends a pulse through the solenoid coil  13  in the second direction D 2  by connecting the first end  15 A of the solenoid coil  13  to the negative terminal of the electrical supply  19  and connecting the second end  15 B of the solenoid coil  13  to the positive terminal of the electrical supply  19 . 
     The switch arm  21  is pivotally mounted to the switch about a pivot axis PA and is biased to the neutral position such that when the switch arm is moved to the open or closed positions OP, CP it sends the pulse and then once it is released it moves back to the neutral position NP. An open bias force OBF provided by a spring is operative to bias the switch arm  21  to the neutral position NP and the switch arm  21  is movable to the open position OP against the open bias force OBF, and similarly a closed bias force CBF also provided by a spring is operative to bias the switch arm  21  to the neutral position NP and the switch arm  21  is movable to the closed position CP against the closed bias force CBF. 
       FIG. 1  schematically illustrates a nozzle assembly  5  that comprises an A-nozzle  9 A and a B-nozzle  9 B where each of the nozzles  9  is configured to spray substantially the same area of ground. These nozzle assemblies  5  with two or more nozzles can be used to vary the spray rate by turning on nozzle  9 A off while  9 B is off, or by turning on nozzle  9 B while  9 B off, or by turning both nozzles  9 A,  9 B or finally by stopping spraying at the nozzle location by turning both nozzles  9 A,  9 B off. 
     In the nozzle assembly of  FIG. 1 , an A-channel  7 A connects the supply conduit  3  to the A-nozzle  9 A and an A-valve  11 A is operative to selectively open and close the A-channel,  7 A and an A-solenoid coil  13 A is operative to selectively move the A-valve  11 A between the open and closed positions. 
     Similarly a B-channel  7 B connects the supply conduit  3  to the B-nozzle  9 B and a B-valve  11 B is operative to selectively open and close the B-channel  7 B, and a B-solenoid coil  13 B is operative to selectively move the B-valve  11 B between the open and closed positions. In the illustration of  FIG. 1  the valve  11 A is shown in the closed position while valve  11 B is shown in the open position. 
     An A-switch selectively delivers a pulse of electrical energy through each A-solenoid coil  13 A in the first direction D 1  or through each A-solenoid coil  13 A in the second opposite direction D 2  and similarly a B-switch  17 B selectively delivers a pulse of electrical energy through each B-solenoid coil  13 B in the first direction D 1  or the second opposite direction D 2 . 
     To close the valve  11 A the pulse of electrical power moves through the solenoid coil  13  in direction D 1  which exerts an electromagnetic force on the piston  23 A drawing it down, in conjunction with the bias force SBF exerted by the spring  25 A, away from the permanent magnet  27 A to the valve closed position shown, and the bias force BF developed by the spring  25 A keeps the valve  11 A closed with no further current through the coil  13 A. 
     To open the valve  11 B the pulse of electrical power moves through the solenoid coil  13  in direction D 2  which exerts an electromagnetic force on the piston  23 B in the opposite direction drawing it upward against the bias force SBF exerted by the spring  25 B, toward the permanent magnet  27 B to the valve open position shown, and permanent magnet  27 B exerts a force on the piston  23 B that overcomes the bias force BF developed by the spring  25 B and keeps the valve  11 B open with no further current through the coil  13 B. 
     Where a large number of solenoids are to be operated by a pulse from a single switch  17  the direct current electrical supply  19  can comprise a capacitor  29  connected to the positive terminal and to the negative of the direct current electrical supply  19  to build up a sufficient charge to deliver all the pulses to each solenoid coil  13 . 
     The present disclosure allows electrical connections to open and close valves  11  using the limited capacity of mobile sprayers, providing a significantly wider range of options for the use of solenoids on such mobile sprayers. 
     The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.