CONTROL SYSTEM FOR A LIQUID PUMP SPRAYER

Abstract

A battery-powered liquid pump sprayer having a control system capable of providing the user with a selectable series of defined spray application pressures, flow rates, and patterns that are accurately sustained over the duration of a spray application session. The pump sprayer has a control system for use with a battery having a voltage supply amount and a motor having a voltage demand amount that is less than the voltage supply amount. A microcontroller of the control system is coupled to the battery and the motor, and is programmed to provide a supply voltage from the battery to the motor and to ensure that the supply voltage is at least as much as the voltage demand amount

Claims

1. A control system for a battery powered liquid pump sprayer, comprising: a battery having a voltage supply amount; a motor having a voltage demand amount that is less than the voltage supply amount; and a microcontroller coupled to the battery and the motor, wherein the microcontroller is programmed to provide a supply voltage from the battery to the motor and to ensure that the supply voltage is at least as much as the voltage demand amount.

2. The control system of claim 1, wherein the microcontroller is programmed to attenuate the supply voltage to match the voltage demand amount if the supply voltage is greater than the voltage demand amount.

3. The control system of claim 2, further comprising a spray flow input having a plurality of user selectable flow rates.

4. The control system of claim 3, wherein the microcontroller is programmed to adjust the supply voltage according to a selected one of the plurality of user selectable flow rates.

5. The control system of claim 4, wherein the microcontroller is programmed to use pulse width modulation to attenuate the supply voltage.

6. The control system of claim 5, wherein the microcontroller is programmed to include a comparator function that can continuously read the supply voltage from the battery and compare it to the voltage demand amount.

7. The control system of claim 6, wherein the microcontroller is programmed to an encoder system for obtaining results from the comparator function and directing pulse width modulation to continuously attenuate the supply voltage so that the supply voltage matches the voltage demand amount.

8. The control system of claim 7, wherein the encoder system provides motor speed information to the comparator.

9. A method of controlling a battery powered liquid pump sprayer, comprising the steps of: providing a battery having a voltage supply amount; providing a motor having a voltage demand amount that is less than the voltage supply amount; using a microcontroller coupled to the battery and the motor to provide a supply voltage from the battery to the motor and to ensure that the supply voltage is at least as much as the voltage demand amount.

10. The method of claim 9, wherein the step of using the microcontroller coupled to the battery and the motor to provide a supply voltage includes the step of attenuating the supply voltage to match the voltage demand amount if the supply voltage is greater than the voltage demand amount.

11. The method of claim 10, further comprising the step of providing a spray flow input having a plurality of user selectable flow rates.

12. The method of claim 11, further comprising the step of using the microcontroller to adjust the supply voltage according to a selected one of the plurality of user selectable flow rates.

13. The method of claim 12, wherein the step of attenuating the supply voltage comprises using pulse width modulation.

14. The method of claim 13, further comprising the step of including a comparator function that can continuously read the supply voltage from the battery and compare it to the voltage demand amount.

15. The method of claim 14, further comprising the step of including an encoder system for obtaining results from the comparator function and directing the pulse width modulation to continuously attenuate the supply voltage so that the supply voltage matches the voltage demand amount.

16. The method of claim 15, further comprising the step of providing motor speed information to the comparator function from the encoder system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:

[0049] FIG. 1 is a perspective view of a prior art manual liquid pump backpack sprayer.

[0050] FIG. 2 is an elevation view of a prior art manual liquid pump backpack sprayer.

[0051] FIG. 3 is a schematic elevation view of a prior art manual liquid pump backpack sprayer.

[0052] FIG. 4 is a perspective view of a prior art battery powered liquid pump backpack sprayer.

[0053] FIG. 5 is an elevation view of a prior art battery powered liquid pump backpack sprayer.

[0054] FIG. 6 is a perspective view of the battery compartment of a battery powered liquid pump backpack sprayer.

[0055] FIG. 7 is a perspective view of charging equipment used with a prior art battery powered liquid pump backpack sprayer.

[0056] FIG. 8 is a schematic view of a prior art battery-powered liquid pump sprayer.

[0057] FIG. 8A is summary of the demonstrable variation in sprayer performance as the battery supply voltage becomes depleted over the duration of a spray session.

[0058] FIG. 9 is a perspective view of a battery powered liquid spray pump sprayer, in accordance with an embodiment.

[0059] FIG. 10 is a schematic view of a battery powered liquid spray pump sprayer, in accordance with an embodiment.

[0060] FIG. 10A is summary of the sprayer performance, in accordance with an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0061] The present disclosure describes a control system for a liquid pump sprayer and is directed to a battery-powered liquid pump sprayer that comprises a novel control system capable of providing the user with a selectable series of defined spray application pressures, flow rates, and patterns that are accurately sustained over the duration of a spray application session.

[0062] FIG. 9 provides an initial overview of the disclosed battery-powered liquid-pump backpack sprayer, where the liquid is filled via cap 302, into tank 301. Harness 300 permits the sprayer to be carried on the user's back. The liquid is pressurized by the battery-powered pump drive system 309, as power switch 307 is engaged. A spray flow control 308 provides for the user to select from one of ten discrete spray nozzle application flow rates (of course, fewer or greater flow rates could be implemented). With power on and the liquid sufficiently pressurized, and with hand-held spray wand 305 aimed appropriately, shutoff 306 is opened, which permits the liquid to flow from the tank and along through hose 325 to outlet spray nozzle 310, where the liquid exits as a pattern.

[0063] A battery charge indicator 312 is conveniently provided adjacent to the power switch 307, so that the user can monitor the in-use state of charge of the rechargeable battery 309.

[0064] As with the previously-described exemplar conventional sprayer, the disclosed sprayer employs a modern nominal 18 V lithium-ion (Li-ion) battery; this battery specifies, as is typical, a safe full-charge state at 21.0 V and a safe depleted state at 16.5 V. The battery is inserted for operation, and removed for convenient charging on a separate charging station.

[0065] The schematic of FIG. 10 represents a more detailed view of the disclosed control system for a battery-powered liquid-pump backpack sprayer. The schematic overview of the sprayer will first be provided, followed by a more specific description of the means by which the novel control system accurately sustains the liquid outlet pressure, and resulting flow rate and nozzle outlet spray pattern over the duration of a spray session.

[0066] The liquid mixture 313 to be sprayed is filled into tank 301 via the opening at fill cap 302, and enters battery 309 and pump drive systems 304 via inlet filter 314. Battery charge indicator 312 indicates the state of charge of the battery 309. A discrete spray flow control 316 enables one of ten specific nozzle application flow rates to be specified by the user. As power switch 307 is engaged, the liquid flows through inlet filter 314 and is pressurized by battery-powered pump drive system 304. With hand-held spray wand 326 aimed appropriately, shutoff 327 is opened, which permits the liquid to then flow along through hose 325 to outlet spray nozzle 328, where the liquid exits as a pattern.

[0067] With continuing reference to FIG. 10, battery and pump drive systems 309 includes novel control system 329. This novel control system comprises a microcomputer controller 330 with unique pulse-width modulation (PWM) and comparator functions. This controller is programmed to receive inputs from battery 309, pressure sensors 332, a unique discrete ten-position spray flow control 316, and power switch 307. After processing these inputs, the controller outputs include a managed supply voltage to the electric motor 334, and battery voltage-state information to battery charge indicator 312.

[0068] As managed by control system 329, the battery powers the electric motor, which drives the liquid pump by mechanical means. Note that this battery voltage, as supplied to the motor, directly controls the speed (revolutions/minute) of the motor which, in similarly direct fashion, controls the pump speed and the resulting pump outlet pressure, flow rate, and ultimate spray pattern for a given nozzle.

[0069] Controller 330, as is a typical requirement for user safety and the integrity of Li-ion batteries, monitors the supply voltage from the battery so as to limit the upper (full-charge) supply condition to 21.0 V, and terminate the battery supply when the voltage becomes depleted to a low charge limit at 16.5 V. Additionally, the controller terminates the battery supply to the motor if pressure sensors 332 detect that either a high pressure limit or low pressure limit has been reached.

[0070] A first aspect of this disclosed control system 329 is spray flow control 316, which enables the user to selectively input into controller 330 one of ten different programmed flow rate/nozzle spray application settings. These programmed, nozzle-specific flow rates, range in a preferred embodiment from 0.1 gpm to 0.5 gpm, with each setting a 0.04 gpm increment; of course, other increments and other ranges of values could be provided. As will be further disclosed, for each application setting as input from spray flow control 316, control system 329 will output a unique supply voltage to motor 334, which will result in a unique motor speed and corresponding pump outlet liquid pressure, flow rate, and nozzle-specific spray pattern.

[0071] A second aspect of this disclosed control system 329 is the application of an electric motor 334 having a nominal demand voltage that is equivalent to the nominal low limit of safe battery supply voltage.

[0072] The low limit of safe battery supply voltage for the considered 18 V Li-ion battery sprayers, as previously discussed, is 16.5 V. Accordingly, unlike the conventional application of an 18 V motor with the 18 V battery supply voltage, here is disclosed the application of a motor with a 16.5 V demand to the 18 V battery. As will be further described, this 16.5 V motor will be specified to deliver the same performance output at the 16.5 V low-limit battery supply voltage that the 18 V motor would deliver at the 16.5 V low-limit supply voltage. Importantly, in this way, the greatest required power output from this disclosed motor will be obtained when both the battery supply voltage and motor demand voltage are 16.5 V.

[0073] Continuing with this second aspect, and as previously discussed, 21.0 V is the upper limit of safe battery supply voltage for the 18 V Li-ion battery sprayers under consideration. Thus, for the disclosed sprayer having the 16.5 V motor configured with performance equivalent to the 18 V motor, there is never a battery supply voltage to the motor that is below the highest demand voltage of the motor. The benefit here is that, as the battery naturally discharges during a spraying session, whereby the supply voltage to the motor drops from the 21.0 V full-charge state to the fully-depleted 16.5 V state, the available supply voltage to the motor is always equal to or greater than the motor's 16.5 V demand.

[0074] A third aspect of this disclosed control system 329 is the unique utilization of a pulse-width modulation (PWM) function within microcomputer controller 330. In coordination with the first and second aspects whereby, with advantage, the available supply voltage to the motor is always equal to or greater than the highest motor demand voltage, this PWM function will be capably directed to continuously attenuate the varying battery supply voltage to the motor so that, for a given flow-control setting, the supply voltage to the motor is beneficially maintained at the motor demand voltage needed for that application setting.

[0075] As will be disclosed next, the PWM is provided a directive control in order to maintain, over the course of a spray session, this continuous and accurate attenuation of the varying supply voltage from the depleting battery.

[0076] The fourth aspect of this disclosed control system 329 is the comparator function within microcomputer controller 330. By continuously reading the varying supply voltage from the battery, and by comparing this available supply voltage to the motor demand voltage as specified by the selected flow rate setting, the comparator can accordingly direct the PWM to appropriately attenuate this supply voltage, so that the directed supply voltage meets, but does not exceed or fall below, this specified motor demand voltage.

[0077] Alternatively, or as a functional enhancement, the comparator function within microcomputer controller 330 may utilize an encoder system as a means to direct the PWM to appropriately and continuously attenuate the supply voltage to the motor so that, with similar beneficial result, the directed supply voltage matches the motor demand voltage as specified by the selected flow rate setting. This encoder system provides motor speed (revolutions per minute) information to the comparator for the purpose of directing PWM voltage attenuation to match the motor demand voltage as specified by the selected flow rate setting.

[0078] In summary, from the schematic of FIG. 10, the four aspects of the disclosed control system 329 comprise spray flow control 316 and the PWM and comparator functions of controller 330, working in collaboration with the designated 16.5 V motor 334, and 18 V battery 309.

[0079] Despite the drop in available supply voltage from the battery as it discharges during operation, these four aspects of the disclosed control system enable the available battery voltage, as supplied to the motor for each often flow control settings, to be accurately aligned and sustained in order to meet each setting's defined application performance requirements for liquid pressure, flow rate, and nozzle spray pattern for the duration a spraying session.

[0080] FIG. 10A demonstrates the benefit of the disclosed control system for a battery-powered liquid pump sprayer. It will be shown that, despite the inevitable drop in battery supply voltage during the spraying session, the sprayer will provide and sustain the user-selected liquid pressure, flow rate, and resulting pattern for the full duration of the spray application session.

[0081] For this application spraying session, the ten-position flow control is set to provide 0.5 gpm at 40 psi with a straight-stream nozzle (note F). As with the equivalent exemplar conventional sprayer, and for the purpose of this comparison, this application setting represents an equivalent highest-performance output from both sprayers.

[0082] As discussed previously, because the disclosed 16.5 V motor is purposefully specified to be equivalent in performance to the conventional 18 V motor, the user-selected flow setting for this 16.5 V motor is obtained, as with the 18 V motor, when the battery supply to the motor is 16.5 volts. With equivalent pumps and nozzles employed, the motor speed necessary to produce this liquid outlet flow and pressure is the same, at 3800 rpm.

[0083] Over the duration of the spraying session, the battery becomes discharged, as expected. As shown, the battery supply voltage dropped from its full-charge upper limit of 21 volts, down to its nominal 18 volts, and eventually down to its full-discharge state limit of 16.5 volts (Input/Battery, row 8, columns P-V).

[0084] The means by which the disclosed control system can beneficially provide and sustain the user-selected liquid pressure, flow rate, and resulting pattern for the full duration of the spray application session is presented in the charted values for the PWM Percent Duty Cycle (Input/Motor, row 10, columns P-V). As directed by the controller comparator function, the controller PWM function provides greatest attenuation at the battery's upper supply voltage of 21.0 V, resulting in a 75 percent PWM duty cycle (rows 8 and 10, column Q). This attenuation provides the needed supply of 16.5 V to the motor.

[0085] As the battery discharges, this charting of the PWM duty cycle shows how the control system continues to provide, with decreasing attenuation provided by the increasing PWM duty cycle, a constant 16.5 V battery supply to the motor.

[0086] Accordingly, this constant 16.5 V supply to the motor enables the motor to drive the pump with a constant speed of 3800 rpm (Input/Motor, row 11, columns P-V)

[0087] With the motor speed maintained at 3800 rpm for the duration of the spray session, the charting of pump pressure and pump flow (note G) demonstrates that the user-selected application setting of 0.50 gpm at 40 psi is accordingly held constant for the session, even as the battery supply voltage is dropping from its upper limit of 21.0 volts to its lower limit of 16.5 volts.

[0088] The disclosed beneficial control of liquid pump performance as charted in FIG. 10A for the selected spray flow setting would be similarly obtained for each of the other nine user-selectable spray flow application settings.

[0089] As has been shown, for both manual and battery-powered liquid pump sprayers, the means for control of liquid pressure is an important aspect of sprayer performance.

[0090] The novel control system disclosed herein improves upon such conventional sprayers by providing a user-selectable series of defined spray application pressures, flow rates, and patterns that are that are accurately sustained over the duration of a spray application session. This control system provides for efficient, accurate, and economical application of the sprayed liquid product.

[0091] While various embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure.

[0092] The above-described embodiments of the described subject matter can be implemented in any of numerous ways. For example, some embodiments may be implemented using hardware, software or a combination thereof. When any aspect of an embodiment is implemented at least in part in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single device or computer or distributed among multiple devices/computers.