WO2022178227A1 - Vacuum regulator system applied to a venturi-metering liquid pump sprayer - Google Patents

Abstract

A sprayer system adapted to draw liquid from a container at an upstream end and discharge the liquid at a downstream end, including (i) a vacuum regulator system for application to the sprayer system and positioned upstream adjacent to the container, wherein the vaccum regulator system comprises (a) a normally closed vacuum-operated regulator; and (b) a fixed bypass restrictor; (ii) a venturi metering system positioned in fluid communication upstream and adjacent to the vacuum regulator system; (iii) a liquid pump assembly positioned in fluid communication upstream and adjacent to the venturi metering system; and (iv) a spray nozzle positioned in fluid communication to the liquid pump and at the downstream end.

Description

VACUUM REGULATOR SYSTEM APPLIED TO A VENTURI-METERING LIQUID PUMP SPRAYER

Cross-Reference to Related Application

[0001] The present application relates and claims priority to Applicant’s U.S. Provisional Patent Application Serial Number 63/150,737, filed February 18, 2021, the entirety of which is hereby incorporated by reference.

Field of the Invention

[0002] The present disclosure is directed generally to a vacuum regulator system applied to a venturi-metering liquid pump.

Background

[0003] Current liquid pump sprayers that mix a separately contained liquid concentrate with pressurized water from the tank (often called “mix-on-exit” sprayers) utilize a simple single venturi metering system that is placed on the inlet side of the liquid pump. Figure 1 presents a labeled schematic description of this conventional sprayer, and Figure 2 displays a perspective illustration showing corresponding labels for an exemplar conventional “mix-on-exit” sprayer. [0004] With primary reference to Figure 1, in use, container 14 is filled with liquid concentrate (typically herbicide or insecticide) to an indicated level and connected to the sprayer. Tank 16 is filled with water to an indicated level. The liquids in both the container 14 and tank 16 are held at atmospheric pressure (0 psi gage).

[0005] The recommended mixture ratio of water to concentrate is set by adjusting mix ratio set dial 15 to the indicated value. This mix ratio set dial functionally positions the appropriate metering orifice 13 with respect to venturi 11.

[0006] To prime the pump (as when little or no liquid is yet in the pump), the user opens adjustable prime/flow valve 5 to the indicated (prime) setting, opens the manual shutoff 3 on the handheld wand, and then activates power switch 7 to run motor 8 which drives liquid pump 6. Consequently, an atmospheric pressure drop is established at the inlet side of the pump that then enables atmospheric pressure to cause water from tank 16 to flow into and through the pump. With air now evacuated from the sprayer flow paths, the water flowing from the tank, through the venturi, and into the pump is at the vacuum (negative) pressure created by the pump.

[0007] With the pump now primed and running, the user sets adjustable valve 5 to an applicable flow setting and adjusts spray nozzle 2 to the desired spray pattern. With water now flowing throughout the sprayer at its operational flow rate for the application session, the venturi effect created by water flow through venturi 11 creates an additional vacuum (negative pressure) at concentrate inlet port 12 that, in summation with the vacuum provided by the pump, acts on the liquid concentrate in container 14.

[0008] This vacuum at concentrate inlet port 12 enables atmospheric pressure to cause the liquid concentrate to flow from container 14, through the previously selected metering orifice 13, and then through concentrate inlet port 12, where it combines with the water flowing through venturi 11. This combined liquid mixture of water and metered concentrate flows into pump 6 at a pressure less than atmospheric and then flows out from the pump under higher pressure through hose 4 and open manual shutoff 3, exiting the sprayer at the outlet of nozzle 2 in the form of a spray pattern 1.

[0009] Liquid application flow rates for a lawn and garden sprayer typically range from .07 to .25 gpm. Importantly, the flow rate of liquid through the sprayer directly affects the amount of vacuum at the venturi that can be employed to meter the liquid concentrate via the concentrate inlet port.

[0010] For a given conventional venturi, these limits of application flow rates place corresponding limits on the vacuum available at the concentrate inlet port.

[0011] As noted above, the vacuum produced at the concentrate inlet port 12 is the sum of the vacuum produced by the inlet side of liquid pump 5 and the beneficial vacuum produced by the venturi effect of the water flowing through the venturi 11. If a venturi is not employed, in which case a simple orifice is substituted, then all of the vacuum produced at the concentrate inlet port is produced by liquid pump 5. In this case where a simple orifice is substituted for a venturi, the efficiency of the sprayer pump and accuracy of metering is reduced.

[0012] Consider now the applicable actual sprayer flow rates and system-producible vacuums. With water from the tank flowing through the single venturi 11, a vacuum is formed due to the venturi effect that acts at concentrate inlet port 12, which is in fluid communication with the liquid concentrate in container 14. Single venturi 11 is optimized to achieve the greatest vacuum obtainable across the limits of application flow rates. At the low flow limit of .07 gpm, the venturi effect vacuum is minimal, at approximately 0 psi, and the venturi effect at the upper flow limit of .25 gpm might be -2.0 psi.

[0013] Concurrently acting at concentrate inlet port 12 is the vacuum produced by liquid pump 6. This vacuum will add to the venturi effect vacuum to produce an overall vacuum acting at the concentrate inlet port. At the low flow limit of .07 gpm, the pump vacuum might be -2.0 psi, and -3.0 psi at the upper flow limit of .25 gpm. Note here that detrimental cavitation within the liquid pump can occur at a vacuum greater than -3.0 psi; this potential for cavitation sets the upper limit of vacuum at -3.0 psi at the upper flow limit, and also decreases efficiency and life of the pump.

[0014] With this summation of vacuum acting concurrently at concentrate inlet port 12, the vacuum available with which to accurately meter the liquid concentrate is -2.0 psi at lowest flow, and -5.0 psi at highest flow. The range of vacuum with which to meter the liquid concentrate is 2.0 psi. Metering orifices 13 are sized to achieve the nominal mix ratios over this 2.0 psi range of vacuum.

[0015] A primary weakness of the conventional liquid pump single venturi concentrate metering lawn and garden sprayer’s ability to achieve the desired mix ratio is this relatively low venturi-effect vacuum (approximately 0 psi in the given example) produced at the low limit of flow through the venturi. Especially when metering more viscous (than water) liquid concentrates at a low application rate, the minimal overall vacuum (the sum of venturi-effect vacuum and pump vacuum, as described above) available may not be sufficient to initiate and accurately maintain the selected mixture ratio.

[0016] A second weakness of this sprayer’s ability to achieve the desired mix ratio is that metering system 10 is only adjustable with respect to the desired mixture ratio setting. The ability of metering system 10 to achieve a specific desired mixture ratio is dependent, however, on 1) the actual water flow rate through the venturi, and 2) the actual viscosity of the liquid concentrate to be metered. These two factors are important design inputs into sizing the geometry of venturi 11 and metering orifice 12, so that the specific mixture ratio can be achieved. During actual sprayer use, the flow is adjusted (within limits, as discussed previously) and the liquid concentrate may be “changed-out” from a liquid with a water-like viscosity to a liquid with a thicker viscosity. As a result, because the flow rate of water and the viscosity of liquid concentrate can vary based on the application, and the metering system 10 is only adjustable with respect to the mixture ratio setting, the design of simple venturi metering system 10 is a compromise that can only approximate the desired mixture ratio at any given time.

[0017] This weakness applies generally to any conventional liquid pump venturi -metering “mix on exit” sprayer that does not provide the operator with the inputs needed to set a specific applicable flow rate value and employ a corresponding viscosity value for the liquid concentrate being sprayed.

[0018] Figure 2 provides selected labels for an exemplar conventional “mix-on-exit” sprayer that reflects the configuration of the schematic. [0019] Note that flow adjustment knob 5 does not provide the operator with a specific flow rate setting value. Adjustable spray nozzle 2 permits the pattern of the outlet spray to be adjusted which, indirectly, also varies the water flow rate to a non-specified value.

[0020] Note also that the concentrate liquid is filled into an attachable container 14; there is no provision to adjust the sprayer with respect to the viscosity of the liquid concentrate. Water is filled into the tanks through fill cap 16.

[0021] Mix ratio set dial 15 is adjusted to a nominal desired mixture ratio by the operator. [0022] With power switch 7 (not shown) engaged, a battery powers motor 8, drives liquid pump 6. The metered mixture of liquid concentrate and water flows through the open manual shutoff 3 via hose 4 and out adjustable nozzle 2.

[0023] Accordingly, there is a need in the art for a venturi-metering liquid-pump sprayer that will aid in overcoming the inherent weaknesses of this conventional system, enabling a sprayer of this type to more accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate across a range of sprayer application flow rates and liquid concentrate viscosities.

Summary

[0024] The present disclosure is directed to a sprayer system.

[0025] According to an aspect is a sprayer system adapted to draw liquid from a container at an upstream end and discharge the liquid at a downstream end, comprising (i) a vacuum regulator system for application to the sprayer system and positioned upstream adjacent to the container, wherein the vacuum regulator system comprises (a) a normally closed vacuum- operated regulator; and (b) a fixed bypass restrictor; (ii) a venturi metering system positioned in fluid communication upstream and adjacent to the vacuum regulator system; (iii) a liquid pump assembly positioned in fluid communication upstream and adjacent to the venturi metering system; and (iv) a spray nozzle positioned in fluid communication to the liquid pump and at the downstream end.

[0026] According to an embodiment, the sprayer system further comprises a manual shut off positioned in fluid communication between the liquid pump and the spray nozzle.

[0027] According to an embodiment, the venturi metering system comprises (i) a single venturi; (ii) a liquid concentrate container in which liquid concentrate is adapted to be contained; (iii) a plurality of metering orifices each one of which can be selectively moved into fluid communication with the liquid concentrate container; and (iv) a conduit extending between the single venturi and the liquid concentrate container and extending through the one metering orifice that is selectively moved into fluid communication with the liquid concentrate container, wherein a concentrate inlet port is positioned at the end of the conduit adjacent the single venturi.

[0028] According to an embodiment, the liquid pump assembly comprises (i) a power source; (ii) a motor coupled to the power source; (iii) a liquid pump coupled to the motor; (iv) a user selectable switch positioned between the motor and the liquid pump; and (v) a manual variable bypass valve that bypasses the liquid pump to permit manual priming of the sprayer. [0029] According to an embodiment, the venturi metering system comprises (i) a dual venturi; (ii) a liquid concentrate container in which liquid concentrate is adapted to be contained; (iii) a plurality of differently sized metering orifices each one of which can be selectively moved into fluid communication with the liquid concentrate container; (iv) a mix ratio set dial that is selectively movable to place any one of the plurality of differently sized metering orifices into fluid communication with the vacuum regulator system; (v) a flush system that is selectively movable into and out of fluid communication with the vacuum regulator system; and (vi) conduits extending between the dual venturi and the liquid concentrate container and extending through the one or more paired sets of metering orifices that are selectively moved into fluid communication with the liquid concentrate container, wherein a concentrate inlet port is positioned at the end of each conduit adjacent each of the two (dual) venturi.

[0030] These and other aspects of the invention will be apparent from the embodiments described below.

Brief Description of the Drawings [0031] The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which: [0032] FIG. 1 is a schematic representation of a conventional liquid pump single venturi concentrate metering sprayer.

[0033] FIG. 2 is a perspective view of a conventional liquid pump single venturi concentrate metering sprayer.

[0034] FIG. 3 is a schematic view of Vacuum Regulator System Applied to Conventional Liquid Pump Single Venturi Concentrate-Metering Sprayer, in accordance with an embodiment.

[0035] FIG. 4A and 4B are schematic views of a Vacuum Regulator-Controlled Liquid Pump Dual Venturi Concentrate-Metering Sprayer with one of the two venturi in fluid communication with the liquid concentrate container and with both of the two venturi in fluid communication with the liquid concentrate container, respectively, in accordance with an embodiment.

[0036] FIG. 5 is a perspective view of a sprayer and its external controls, in accordance with an embodiment.

Detailed Description of Embodiments

[0037] The present disclosure describes a vacuum regulator system for application to single venturi mix on exit sprayer and to a liquid pump concentrate metering lawn and garden sprayer. [0038] Referring to Figure 3 schematically shown is the application of a vacuum regulator system to a conventional liquid pump single-venturi concentrate-metering (mix-on-exit) sprayer. This vacuum regulator system provides more accurate control of the desired mixture ratio output across the range of sprayer application flow rates. Liquid application flow rates for a lawn and garden sprayer typically range from .07 to .25 gpm.

[0039] The proposed vacuum regulator system 16 is shown applied to a conventional mix- on-exit sprayer (as described in in the Background) and is placed upstream of metering system 10

[0040] This regulator system 16 comprises a normally-closed vacuum-operated regulator 17 and a fixed bypass restrictor 18. This regulator system is designed to beneficially provide, at the sprayer’s lowest application flow rate, a predetermined and corresponding operating vacuum to the inlet side of single venturi 12.

[0041] Furthermore, at all sprayer application flow rates above the operational minimum, regulator system 16 then prevents the operating vacuum to the inlet side of single venturi 12 from increasing beyond that value predetermined for lowest flow, as would otherwise be the case. As a result, the regulator system beneficially maintains a predetermined maximum and stable operating vacuum at the inlet side of venturi 12 over the full range of sprayer application flow rates.

[0042] Thusly, this employment of vacuum regulator system 16 advantageously enables the design configuration of metering system 10 to be optimized for an improved ability to more accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate over the full range of sprayer application flow rates.

[0043] Without this establishment of a maximum operating vacuum that regulator system 16 provides to the inlet side of single venturi 11 over the full range of application flow rates, the venturi inlet vacuum has been found to both increase and vary unpredictably as the sprayer operational flow rate is adjusted. This uncontrolled and unstable variation of vacuum at the inlet to venturi 11 hinders the ability of a conventional single venturi metering system 10 to accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate across the range of sprayer application flow rates.

[0044] To describe vacuum regulator system 16 more fully, vacuum regulator 17 is configured to establish a maximum potential vacuum value at a flow rate that corresponds to the low limit of the range of the sprayer application flow rates. If and when the flow rate during a spraying session is increased above this low limit, as when adjusting nozzle 2 to change the spray pattern from a fine mist to a coarser spray, the regulator will continue to maintain this specific maximum vacuum value at the inlet to venturi 11. Even when the user adjusts the sprayer to its maximum upper limit of flow, the vacuum value provided by the regulator to the inlet of venturi 11 will remain stable at the intended value of maximum vacuum. The specific and stable vacuum value provided to the inlet of the venturi by the vacuum regulator is beneficial to the ability of single venturi metering system 10 to more accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate across the applicable range of sprayer application flow rates and liquid concentrate viscosities.

[0045] Consider now, for this disclosed vacuum regulator system, the applicable actual sprayer flow rates and system-producible vacuums. At the sprayer’s low limit flow rate of .07 gpm, the corresponding design vacuum value for the vacuum regulator is to be -1.0 psi. As the sprayer application flow rate is increased, for example from the low limit of .07 gpm to a greater flow of .15 gpm, the regulated vacuum would remain at -1.0 psi. Even at the upper limit of flow, at .25 gpm for this sprayer, the vacuum provided by the regulator to the inlet of venturi 11 will remain at -1.0 psi. [0046] In summary, and with continued reference to Figure 3, the upstream location of vacuum regulator system 16 provides this stable maximum vacuum of -1.0 psi to the inlet of single venturi 11 over the full range of sprayer application flow rates.

[0047] Considered now with this example is the function of vacuum regulator system 16 at flow rates below the lowest sprayer application flow rate of .07 gpm. These flow rates of 0.0 gpm (no flow) to .07 gpm (minimum applicable flow) would prevail during initial pump startup and priming. Across this range of flow rates, vacuum regulator 17 remains closed. During priming of pump 5, an initial drop of atmospheric pressure formed within the inlet side of the running pump initiates the flow of water from the tank to follow a path through bypass fixed resistor 18 and along through venturi 11 to the pump. The orifice size of bypass fixed resistor 18 is designed to create the design-intended pressure drop of -1.0 psi to the inlet of venturi 11 once the water reaches the sprayer’s minimal functional flow rate of .07 gpm.

[0048] Note that, at flow rates below the functional minimum of .07 gpm, venturi metering system 10 is not active. As flow rates below .07 gpm are not applicable for spraying, venturi metering system 10 is thusly designed to not begin functional metering of the liquid concentrate until the sprayer flow rate reaches the minimum flow rate of .07 gpm.

[0049] Once air is fully evacuated from the flow paths, the running liquid pump 5 is fully primed and the flow rate of water increases such that, at the eventual flow rate of .07 gpm, vacuum regulator 17 intentionally opens at the corresponding design vacuum value of -1.0 psi. The regulator now maintains the -1.0 psi as a maximum vacuum to the inlet of venturi 11, even as subsequent flow may increase and decrease within the full range of sprayer application flow rates.

[0050] With continued reference to Figure 3, an overview of the vacuum regulator applied to a conventional liquid pump single venturi concentrate-metering sprayer is disclosed.

[0051] In use, container 14 of concentrate liquid (e.g., herbicide, insecticide) is connected to the sprayer, and the water tank 19 is filled with water to an indicated level. The recommended mixture ratio of concentrate to water is set by adjusting mix ratio set dial 15 to the indicated value. This mix ratio set dial 15 functionally positions the appropriate metering orifice 12 with respect to single venturi 11.

[0052] To then prime (i.e., to evacuate air from) the pump, the user sets prime/flow adjustment valve 9 to the prime (maximum flow) setting, opens manual shutoff 3 on the handheld wand, and then activates power switch 8 to run motor 7 which drives liquid pump 5. Optionally, a pulse width modulator (not shown) could be employed to correlate and control the motor-pump speed with the user-set flow value. Batteries 6 are provided to power the motor.

[0053] Consequently, an initial air vacuum is established within the “dry” running liquid pump 5 that then enables atmospheric pressure to cause water from tank 19 to subsequently flow through the bypass fixed resistor 18 of vacuum regulator system 16, then through single venturi 11 and into the pump.

[0054] With the pump now primed and running, and manual shutoff 3 continued to be held open, water flows through the entire sprayer and exits nozzle 2. By design, the initial water flow through bypass fixed resistor 18 causes the liquid pressure to drop within the flow paths on the inlet side of pump 5. Once the vacuum at the inlet to venturi 11 reaches -1.0 psi (at the intended flow rate of .07 gpm), normally-closed regulator 17 opens and, with water now flowing through the regulator, then continues to maintain this maximum negative liquid pressure on the inlet side of single venturi 11 at -1.0 psi across the range of application flow rates of .07 gpm to .25 gpm.

[0055] For the particular spraying application, the user then sets flow adjustment valve 9 to an indicated applicable (e.g., LOW - HIGH) flow rate and adjusts spray nozzle 2 to the desired spray pattern 1 (e.g., FAN - STREAM). Although these two adjustments vary the flow of water as the adjustments are made, once adjusted the flow of water from the tank is constant through the entire sprayer.

[0056] Considering now the water from the tank flowing through the single venturi 11, a vacuum is formed due to the venturi effect that acts at concentrate inlet port 13, which is in fluid communication with the liquid concentrate in container 14. Single venturi 11 is optimized to achieve the greatest vacuum obtainable across the limits of application flow rates. At the low flow limit of .07 gpm, the optimized venturi effect vacuum might be -1.0 psi. At the upper flow limit of .25 gpm, the venturi effect vacuum might be -3.0 psi.

[0057] Concurrently acting at concentrate inlet port 13 is the vacuum produced by the flowing liquid at the intake to liquid pump 5. This vacuum will add to the venturi effect vacuum to produce an overall vacuum acting at the concentrate inlet port. At the low flow limit of .07 gpm, the pump vacuum might be -2.0 psi and, at the upper flow limit of .25 gpm the vacuum might be -3.0 psi. Note here that, at these flow rates, detrimental cavitation within the liquid pump can occur at a vacuum greater than -3.0 psi; this potential for cavitation sets the upper limit of vacuum at the pump inlet to -3.0 psi at the upper flow limit in this example.

[0058] With this summation of venturi -effect vacuum and inlet pump vacuum acting concurrently at concentrate inlet port 13, the vacuum available with which to accurately meter the liquid concentrate is -3.0 psi at lowest flow, and -6.0 psi at highest flow. The range of vacuum with which to meter the liquid concentrate is 3.0 psi.

[0059] The benefit of the vacuum regulator is now evident when comparing the above disclosed liquid-pump single-venturi concentrate metering sprayer with vacuum regulator to the conventional liquid-pump single-venturi concentrate metering sprayer (without the vacuum regulator).

[0060] While the range of operating vacuum (3.0 psi) is the same, the sprayer with the vacuum regulator has greater (an additional -1.0 psi) vacuum available for metering across the operating flow rates.

[0061] Chart 1 shows this comparative benefit that the proposed vacuum regulator provides. At left, the conventional sprayer (without the vacuum regulator, as previously described in Part 1) provides a concentrate inlet port vacuum that ranges from -2.0 psi to -5.0 psi over the operating limits of flow. At right, the sprayer with the vacuum regulator provides an improved concentrate inlet port vacuum that ranges now from -3.0 psi to -6.0 psi over the operating limits of flow. Beneficially, the sprayer with the vacuum regulator has an additional -1.0 psi vacuum

Chart 1 .

available for metering across the operating flow rates.

[0062] This additional vacuum provided by the vacuum regulator enables a sprayer of this type to more accurately achieve and maintain an application-specific mixture ratio of water-to- liquid concentrate across a range of sprayer application flow rates and liquid concentrate viscosities. to [0063] Application of the innovative vacuum regulator to a unique liquid pump concentrate metering lawn and garden sprayer that employs aspects of the SOFT TWO spraying system. [0064] This disclosed system will be herein referred to as the SOFT THREE sprayer. [0065] This new SOFT THREE sprayer is in continuation with the following previous FGI inventions: US Patent No. 6,896,203 Bl, US Patent Nos. 8,622,320 B2 and 9,302,283 B2. [0066] These previously-developed systems comprise a sprayer system with a separate liquid concentrate container and a user-adjustable mix ratio function via a unique dual-venturi manifold system that selectively meters and mixes a given liquid concentrate with pressurized water from the tank.

[0067] Additionally, one of the prior sprayers provides a self-flush system that cleans the liquid concentrate flow paths with pressurized water from the tank.

[0068] With these prior systems, a compressed air pump is employed to pressurize the tank water.

[0069] Instead of a compressed air pump as used in the prior sprayers, this new SOFT THREE sprayer now employs a liquid pump to pressurize the water from the tank and, with the addition of the proposed unique vacuum regulator system, utilizes aspects of these previously-patented systems (refer to the patents for more details) to include:

[0070] - separately removable and transparent concentrate jar with check valves that enable on-shelf storage,

[0071] - concentrate-jar-to-tank attachment mechanism with quick attach and release and with check valves to prevent drip/leaking of fluid,

[0072] - user-adj usted mixture metering system with modular dual-venturi manifold, and

[0073] - selectable water-flush system for cleaning concentrate circuits.

[0074] One aspect of the present invention is application of a vacuum regulator system to a liquid pump sprayer that also incorporates unique aspects of the previously developed sprayers. This resulting sprayer system will be referred to as the SOFT THREE sprayer.

[0075] The overall purpose of this innovative vacuum regulator system is to more accurately control the mixture ratio output of the liquid pump sprayer, especially as it pertains to effectively metering more viscous (than water) liquid concentrates over the operational range of flow rates employed in lawn and garden applications.

[0076] Figures 4A and 4B present a labeled schematic description of the proposed SOFT THREE sprayer, in which the innovative vacuum regulator system 20 is combined with the aforementioned aspects of the prior dual-venturi concentrate-metering sprayer. Those specific aspects are identified here as separate liquid concentrate container 15, a metering system 11 that comprises user-adjustable mix ratio setting system 16 with dual-venturi 12, and self-flush system 17.

[0077] As previously mentioned, instead of the upstream compressed air-over-water pump from the prior sprayer, the SOFT THREE sprayer employs a liquid pump 5 that is placed downstream of the metering system 11. Liquid pump 5 provides the ultimate vacuum that enables both water from the tank and liquid concentrate from its container to be successfully combined and metered via metering system 11.

[0078] With continued reference to Figures 4A and 4B, the proposed vacuum regulator system 20 is placed upstream of dual venturi 12.

[0079] This vacuum regulator system 20 comprises a normally-closed vacuum-operated regulator 22 and a fixed bypass restrictor 21. This regulator system is designed to beneficially provide, at the sprayer’s lowest application flow rate, a predetermined and corresponding operating vacuum to the inlet side of dual venturi 12.

[0080] Furthermore, at all sprayer application flow rates above the operational minimum, regulator system 20 then prevents the operating vacuum to the inlet side of dual venturi 12 from increasing beyond that value predetermined for lowest flow, as would otherwise be the case. As a result, the regulator system beneficially maintains a predetermined maximum and stable operating vacuum at the inlet side of dual venturi 12 over the full range of sprayer application flow rates.

[0081] Thusly, this employment of vacuum regulator system 20 advantageously enables the design configuration of metering system 11 to be optimized for an improved ability to more accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate over the full range of sprayer application flow rates.

[0082] Without this establishment of a maximum operating vacuum that regulator system 20 provides to the inlet side of dual venturi 12 over the full range of application flow rates, the venturi inlet vacuum has been found to both increase and vary unpredictably as the sprayer operational flow rate is adjusted. This uncontrolled and unstable variation of vacuum at the inlet to venturi 12 would hinder the ability of the dual venturi metering system 11 to accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate across the range of sprayer application flow rates.

[0083] To describe system 20 more fully, vacuum regulator 22 is configured to establish a maximum potential vacuum value at a flow rate that corresponds to the low limit of the range of the sprayer application flow rates. If and when the flow rate during a spraying session is increased above this low limit, as when adjusting nozzle 2 to change the spray pattern from a fine mist to a coarser spray, the regulator will continue to maintain this specific maximum vacuum value at the inlet to dual venturi 12. Even when the user adjusts the sprayer to its maximum upper limit of flow, the vacuum value provided by the regulator to the inlet of dual venturi 12 will remain stable at the intended value of maximum vacuum. The specific and stable vacuum value provided to the inlet of the venturi by the vacuum regulator is beneficial to the ability of dual venturi metering system 12 to more accurately achieve and maintain an application-specific mixture ratio of water-to-liquid concentrate across the applicable range of sprayer application flow rates and liquid concentrate viscosities.

[0084] As an example, for this disclosed vacuum regulator, at the sprayer’s low limit flow rate of .07 gpm, the corresponding design vacuum value is to be -1.0 psi. As the application flow rate is increased, for example from the low limit of .07 gpm to a greater flow of .15 gpm, the regulated vacuum would remain at -1.0 psi. Even at the upper limit of flow, at .25 gpm for this sprayer, the vacuum provided by the regulator to the inlet of venturi 11 will remain at -1.0 psi.

[0085] In summary, and with continued reference to Figures 4A and 4B, the upstream location of vacuum regulator system 20 provides this stable maximum vacuum of -1.0 psi to the inlet of dual venturi 12 over the full range of sprayer application flow rates.

[0086] Considered now with this example is the function of vacuum regulator system 20 at flow rates below the lowest sprayer application flow rate of .07 gpm. These flow rates of 0.0 gpm (no flow) to .07 gpm (minimum applicable flow) would prevail during initial pump startup and priming. Across this range of flow rates, vacuum regulator 22 remains closed. During priming of pump 5, an initial drop of atmospheric pressure formed within the inlet side of the running pump initiates the flow of water from tank 23 to follow a path through bypass fixed resistor 21 and along through dual venturi 12 to the pump. The orifice size of bypass fixed resistor 21 is designed to create a pressure drop of -1.0 psi to the inlet of dual venturi 12 once the water reaches the sprayer’s minimal functional flow rate of .07 gpm.

[0087] Note that, at flow rates below the functional minimum of .07 gpm, metering system 11 is not active. As flow rates below .07 gpm are not applicable for spraying, metering system 11 is thusly designed to not begin functional metering of the liquid concentrate until the sprayer flow rate reaches a flow rate of .07 gpm.

[0088] Once air is fully evacuated from the flow paths, the running liquid pump 5 is fully primed and the flow rate of water increases such that, at the eventual flow rate of .07 gpm, vacuum regulator 22 intentionally opens at the corresponding design vacuum value of -1.0 psi. The regulator now maintains the -1.0 psi as a maximum vacuum to the inlet of dual venturi 12, even as subsequent flow may increase and decrease within the full range of sprayer application flow rates.

[0089] With continued reference to Figures 4A and 4B, an overview of the vacuum regulator applied to the prior developed liquid pump dual venturi concentrate-metering sprayer is now disclosed.

[0090] In use, container 15 of concentrate liquid (e.g., herbicide, insecticide) is connected to the sprayer, and the water tank 23 is filled with water to an indicated level. The recommended mixture ratio of concentrate to water is set by adjusting mix ratio set dial 18 to the indicated value. This mix ratio set dial 18 functionally positions the appropriate metering orifice 14 with respect to dual venturi 12.

[0091] To then prime (i.e., to evacuate air from) the pump, the user sets flow control knob 10 to the prime (maximum flow) setting, opens manual shutoff 3 on the handheld wand, and then activates power switch 9 to run motor 7 which drives liquid pump 5. A pulse width modulator 8 is employed to correlate and control the motor-pump speed with the user-set flow value. Batteries 6 are provided to power the motor.

[0092] Consequently, an initial air vacuum is established within the “dry” running liquid pump 5 that then enables atmospheric pressure to cause water from tank 23 to subsequently flow through the bypass fixed resistor 21 of vacuum regulator system 22, then through dual venturi 12 and into the pump.

[0093] With the pump now primed and running, and manual shutoff 3 continued to be held open, water flows through the entire sprayer and exits nozzle 2. By design, the initial water flow through bypass fixed resistor 21 causes the liquid pressure to drop within the flow paths on the inlet side of pump 5. Once the vacuum at the inlet to dual venturi 12 reaches -1.0 psi (at the intended flow rate of .07 gpm), normally-closed regulator 22 opens and, with water now flowing through the regulator, then continues to maintain this maximum negative liquid pressure on the inlet side of dual venturi 12 at -1.0 psi across the range of application flow rates of .07 gpm to .25 gpm.

[0094] For the particular spraying application, the user then sets flow control knob 10 to an indicated applicable (e.g., LOW - HIGH) flow rate and adjusts spray nozzle 2 to the desired spray pattern 1 (e.g., FAN - STREAM). Although these two adjustments vary the flow of water as the adjustments are made, once adjusted the flow of water from the tank is constant through the entire sprayer.

[0095] Considering now the water from the tank flowing through the dual venturi 12, a vacuum is formed due to the venturi effect that acts at concentrate inlet ports 13, which is in fluid communication with the liquid concentrate in container 15. Dual venturi 12 are optimized to achieve the greatest vacuum obtainable across the limits of application flow rates. At the low flow limit of .07 gpm, the optimized venturi effect vacuum might be -1.0 psi. At the upper flow limit of .25 gpm, the venturi effect vacuum might be -3.0 psi.

[0096] Concurrently acting at concentrate inlet ports 13 is the vacuum produced by the flowing liquid at the intake to liquid pump 5. This vacuum will add to the venturi effect vacuum to produce an overall vacuum acting at the concentrate inlet ports. At the low flow limit of .07 gpm, the pump vacuum might be -2.0 psi and, at the upper flow limit of .25 gpm the vacuum might be -3.0 psi. Note here that, at these flow rates, detrimental cavitation within the liquid pump can occur at a vacuum greater than -3.0 psi; this potential for cavitation sets the upper limit of vacuum at the pump inlet to -3.0 psi at the upper flow limit in this example.

[0097] With this summation of vacuum acting concurrently at concentrate inlet ports 13, the vacuum available with which to accurately meter the liquid concentrate is -3.0 psi at lowest flow, and -6.0 psi at highest flow. The range of vacuum with which to meter the liquid concentrate is 3.0 psi.

[0098] The benefit of the vacuum regulator is now evident when comparing the above disclosed SOFT THREE sprayer (with vacuum regulator) to the conventional liquid-pump single-venturi concentrate metering sprayer (without vacuum regulator).

[0099] Chart 2 shows this comparative benefit that the proposed vacuum regulator provides. At left, the conventional sprayer (without the vacuum regulator, as previously described in Part 1) provides a concentrate inlet port vacuum that ranges from -2.0 psi to -5.0 psi over the operating limits of flow. At right, the previously-disclosed SOFT TWO sprayer, now with the beneficial addition of the vacuum regulator, provides a concentrate inlet port vacuum that ranges now from -3.0 psi to -6.0 psi over the operating limits of flow. Beneficially, this sprayer with the vacuum regulator has an additional -1.0 psi vacuum available for metering across the operating flow rates.

Chart 2.

[00100] Additionally, the SOFT THREE sprayer’s dual venturi metering system 12, as described in the previously-released SOFT TWO disclosure, has a superior ability to meter more viscous (than water) liquid concentrates. The proposed vacuum regulator system 20 builds upon this superior metering ability to more robustly meter more viscous liquid concentrates.

[00101] Figure 5 portrays a correspondingly-labeled perspective view of an embodiment of this SOFT THREE sprayer, with respect to the controls and main components that the user would operate.

[00102] Note that spray/flush set knob 19 and mix ratio set dial 18 are the respective controls for operation of the previously-disclosed water flush and mixture ratio systems of the sprayer. Also carried over from the previously-disclosed sprayer is the separately removable and transparent concentrate j ar 15, and concentrate container quick attach and release system 25. [00103] Manual shut off 3 is shown as part of the wand handle, which is connected to the sprayer via hose 4. Adjustable nozzle 2 enables the spray to range from fine mist (low flow rate) to straight stream (high flow rate). Spray/flush set knob 19 is employed to flush liquid concentrate from the sprayer after use.

[00104] New to the user controls in this SOFT THREE embodiment is power switch 9, as batteries and an electric motor are employed to pressurize the water via the liquid pump system 5, and flow control knob 10, which controls the sprayer outlet flow via a pulse width modulator and microcomputer that correlate the setting value to the motor speed. With the elimination of the manual compressed air pump, carry handle 24 is now integrated into the water fill cap atop water tank 23.

[00105] 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.

[00106] 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.

Claims

Claims

What is claimed is:

1 A sprayer system adapted to draw liquid from a container at an upstream end and discharge the liquid at a downstream end, comprising: a. vacuum regulator system for application to the sprayer system and positioned upstream adjacent to the container, comprising: i. a normally closed vacuum-operated regulator; and ii. a fixed bypass restrictor; b. a venturi metering system positioned in fluid communication upstream and adjacent to the vacuum regulator system; c. a liquid pump assembly positioned in fluid communication upstream and adjacent to the venturi metering system; and d. a spray nozzle positioned in fluid communication to the liquid pump and at the downstream end.

2. The sprayer system according to claim 1, further comprising a manual shut off positioned in fluid communication between the liquid pump and the spray nozzle.

3. The sprayer system according to claim 1, wherein the venturi metering system comprises: a. a single venturi; b. a liquid concentrate container in which liquid concentrate is adapted to be contained; c. a plurality of metering orifices each one of which can be selectively moved into fluid communication with the liquid concentrate container; and d. a conduit extending between the single venturi and the liquid concentrate container and extending through the one metering orifice that is selectively moved into fluid communication with the liquid concentrate container, wherein a concentrate inlet port is positioned at the end of the conduit adjacent the single venturi.

4. The sprayer system according to claim 1, wherein the liquid pump assembly comprises: a. a power source; b. a motor coupled to the power source; c. a liquid pump coupled to the motor; d. a user selectable switch positioned between the motor and the liquid pump; e. a manual variable bypass valve that bypasses the liquid pump to permit manual priming of the sprayer.

5. The sprayer system according to claim 1, wherein the venturi metering system comprises: a. a dual venturi; b. a liquid concentrate container in which liquid concentrate is adapted to be contained; c. a plurality of differently sized metering orifices each one of which can be selectively moved into fluid communication with the liquid concentrate container; d. a mix ratio set dial that is selectively movable to place any one of the plurality of differently sized metering orifices into fluid communication with the vacuum regulator system; e. a flush system that is selectively movable into and out of fluid communication with the vacuum regulator system; and f. conduits extending between the dual venturi and the liquid concentrate container and extending through the one or more paired sets of metering orifices that are selectively moved into fluid communication with the liquid concentrate container, wherein a concentrate inlet port is positioned at the end of each conduit adjacent each of the two (dual) venturi.