AU2011224129A1 - System and Method for Dispensing Controlled Amounts of an Additive Within a Carrier - Google Patents

Abstract

A system and method for combining an additive with a carrier fluid in a spray nozzle is provided. The carrier fluid is fed to one or more nozzles that comprise an embedded Venturi. The Venturi comprises an induction port connected to an additive supply. As the carrier fluid flows through the nozzle, the flow creates a vacuum or 10 suction force that draws in the additive. Of particular advantage, the concentration of the additive combined with the carrier fluid can be maintained constant even if the flow rate of the carrier fluid varies. The system and process are particularly well suited for spraying fields, such as crop fields or orchards, with an agrochemical. co00 cow - - L

Description

AUSTRALIA Patents Act 1990 DIVISIONAL PATENT SPECIFICATION Name of Applicant: The Regents of the University of California Actual Inventor: Durham K GILES Address for Service: Cullens Patent & Trade Mark Attorneys Level 32, 239 George Street Brisbane QLD 4000 Australia Invention Title: System and Method for Dispensing Controlled Amounts of an Additive Within a Carrier The following statement is a full description of this invention, including the best method of performing it, known to the applicant: -2 5 SYSTEM AND METHOD FOR DISPENSING CONTROLLED AMOUNTS OF AN ADDITIVE WITHIN A CARRIER FIELD OF THE INVENTION 10 This technology pertains generally to liquid sprayer systems and more particularly to the on-demand metering, mixing, atomization and dispersal of a number of liquid components in a single spray liquid mixture. The technology comprises a system and method for at-nozzle injection of agrochemicals. 15 BACKGROUND Mere reference to background art herein should not be construed as an admission that such art constitutes common general knowledge in relation to the invention. Modern agriculture is becoming increasingly dependent on the efficient and 20 accurate application of liquid fertilizers and crop protection agents in order to be profitable and environmentally responsible. Agricultural chemicals may be applied as sprays of liquid solutions, emulsions or suspensions from a variety of delivery systems. Typical systems pressurize liquid from a reservoir and atomize a liquid stream into droplets through a nozzle. Nozzles may be selected to provide a range of droplet sizes, 25 spray distribution patterns and flow rates for a desired liquid material application. Spray distribution, droplet size, droplet velocity and flow rate are important considerations in field applications. Ideally, sprays of properly sized droplets will produce uniform coverage of material over the vegetation, the ground or other substrate. Spray distribution is the uniformity of coverage and the pattern and size of the spray 30 area, comprising the overlap of spray patterns between nozzles. Poor spray distribution can limit the efficacy of an application and may lead to adverse environmental injuries, poor crop yields and increased costs. In agricultural spraying, the applied liquid often contains a number of constituents that are mixed prior to application. Once mixed in a central reservoir, the -3 5 concentration and relative ratios of the individual components in the carrier liquid cannot be altered and the mix may have a limited tank life. Additionally, some constituents, either active ingredients, inert materials in the pesticide formulations or adjuvants selected by the applicator, may be chemically or physically incompatible and not mix properly. 10 Chemical injection systems, where carrier fluids, active ingredients and adjuvants are mixed during application, rather than prior to application, have been developed and marketed for agricultural spraying. In these systems, a central pump propels the carrier fluid, consisting of the primary diluent, often water, and perhaps a mixture of compatible materials to the nozzles for distribution. The incompatible fluid 15 components are propelled by separate pumps, from separate reservoirs, and injected into the carrier fluid flow either upstream of the carrier pump or downstream of the carrier pump. Additionally, it is sometimes desirable to apply some of the spray liquid components only to certain portions of a crop field to be treated. In those situations, the 20 entire mix of spray liquid components is not prepared prior to initiating the spray application job. Rather, the components that are to be applied to certain portions of the field are applied using a separate spray system containing only the component to be applied singularly. The limitations of common injection systems have been investigated and 25 documented by researchers in the technical field of agricultural spraying. Steward and Humburg (2000), investigating injection system for maintaining a constant deposition rate of spraying as ground speed of a spraying vehicle varied, found that direct injection systems can reduce much of the application rate error that results from variations in the ground speed. They also found that chemical injection with carrier flow rate control 30 resulted in less application error than when the carrier flow rate was held constant and the injected chemical rate varied, as it minimized concentration variations and reduced transport delays. One disadvantage of some direct injection systems is that the lag time from initiation of an injection chemical rate change to the time when the new rate of chemical -4 5 actually leaves the nozzles can lead to chemical application rate errors during transient response times. A commercial injection system has also been proposed for maintaining a constant concentration circulating in a chamber awaiting sensor-triggered spot spraying of weeds. The system maintained a desired concentration over a range of operating 10 conditions. The fundamental limitation with many commercial injection systems, however, can be due to the basic configuration where the central injection point is located immediately upstream or downstream from the carrier liquid pump. This results in lengthy hose and pipe distances from the injection point to the nozzles. Moreover, the 15 length of fluid passage from the injection point to each nozzle is variable. The consequence of this configuration is that the time delays between changes in injection rate and the arrival of the altered rate at the nozzles are lengthy and vary from nozzle to nozzle. Therefore, application rates of the injected materials are non-uniform across the boom and temporally and spatially variable in an unintended and undesirable manner. 20 A solution to the problems resulting from a central injection point is to inject materials directly at the nozzle inlet. However, this configuration is not without considerable challenges; pumping and metering of the injected fluid must be distributed along the spray booms and adequate mixing must occur within the nozzle during a brief time period. Crowe el al. (2005) reported the development of an "at-nozzle" 25 conductivity probe for high-speed measurement of transient injection events. Further work by Downey et al. (2006) investigated the use of miniature metering valves at individual spray nozzles. The system provided rapid response for triggered spraying; however, the components were expensive, complex and required a pressurized source of injection liquid near the spray nozzle. 30 Previous systems addressing injection at the nozzle inlet have required pumping and metering systems and modification of nozzle plumbing. An additional question has related to the degree of mixing within the nozzle before discharge. Pressurized lines of highly concentrated pesticide are often considered a potential hazard. One type of nozzle that has been used in prior spraying systems is the air -5 5 induction nozzle. Air induction nozzles are constructed with an embedded Venturi induction port fabricated into the nozzle assembly. The Venturi port creates a vacuum that induces the flow of ambient air into the nozzle, resulting in enlarged droplet size spectra in an attempt to mitigate spray drift, that is, the unintended and undesirable movement of spray droplets away from their intended target. Ambient wind, coupled 10 with small sized droplets, is the prime cause of spray drift. Air induction nozzles have been used commercially as a simple means of drift reduction in agricultural field spraying. For typical nozzles tested, the degree of air entrainment ranged from 0.2 to 0.6 1 min-'. Air induction nozzles have shown some ability to control droplet size produced by the nozzles. Droplet size can be affected by 15 the degree of air entrainment and/or by the orifice size of the nozzle. However, sprayer systems using air induction nozzles have the same problems described heretofore as systems using other types of nozzles. Accordingly, there is a need for a sprayer system in which injection of an agrochemical into a carrier fluid or carrier mixture of fluids can be achieved easily, 20 reliably and without complex components. Moreover, there is a need for a system that reduces time delays between injection and dispersal of the spray mixture and/or one that provides greater uniformity in distribution of chemical mixtures throughout lengthy spray nozzle arrays. 25 SUMMARY According to one aspect of the present invention, there is provided a system for dispensing controlled amounts of an additive mixed with a carrier, comprising: one or more dispensing and mixing nozzles, each nozzle comprising a Venturi 30 and an induction port in communication with the Venturi; a carrier fluid supply connected to each nozzle; an additive fluid supply connected to the induction port of each nozzle; and a control system for controlling the flow for the additive fluid, the carrier fluid, or both to each nozzle; -6 5 wherein carrier fluid flow through the Venturi in the nozzle causes additive fluid to be drawn into the nozzle and mixed with the carrier fluid prior to exiting the nozzle. According to another aspect of the present invention, there is provided a method for dispensing controlled amounts of an additive mixed with a carrier, comprising: providing a dispensing and mixing nozzle having an embedded Venturi therein 10 and an induction port in communication with the Venturi; connecting an additive liquid supply to the induction port of the nozzle; flowing a carrier fluid through the Venturi in the nozzle, thereby causing a pressure drop or vacuum that draws additive fluid into the Venturi and mixes the additive liquid with the carrier fluid; and 15 dispensing the mixed carrier fluid and additive liquid from the nozzle. According to another aspect of the present invention, there is provided in a spraying system having a nozzle with an internal Venturi and an air inlet to the Venturi, and a carrier fluid supply connected to the nozzle, the improvement comprising an additive fluid supply connected to the air inlet for mixing an additive fluid drawn into 20 the nozzle by the Venturi effect with a carrier fluid flowing through the nozzle. Nozzles containing a Venturi may be used to combine controlled amounts of an additive, such as an agrochemical, with a carrier fluid prior to discharge. The present inventor discovered that the nozzles may be used as simple robust injection components, with the pumping and metering functions achieved by the Venturi 25 passages. In such a use, injection can be achieved at each nozzle simultaneously and through the use of low pressure, inherently safe liquid supply plumbing. It was further discovered that the Venturi-based, air induction nozzles may provide a self regulating system where the concentration of injected fluid in the spray stream emitted from the nozzle can be maintained at a constant level even as the carrier 30 fluid flow rate varied. The system may be useful for the application of fluid mixtures where one or more components of the mixture may be physically incompatible when prepared as a mixture in a storage tank. In one embodiment, a fluid connection is made into the existing air inlet port of -7 5 an air induction nozzle. The liquid to be injected is supplied to the inlet port through the vacuum created by the Venturi; once entered into the Venturi, the injected fluid mixes with the carrier fluid and is dispensed as a fluid mixture. In another embodiment, a metering orifice is introduced between the fluid connection into the spray nozzle Venturi inlet and the injected fluid supply reservoir. 10 The metering orifice determines the relative flow rate between the carrier fluid and the injected fluid and thereby controls the concentration of injected fluid in the dispensed spray liquid from the nozzle. In another embodiment, an electronic throttling valve is used to alter the effective metering orifice between the nozzle Venturi inlet and the injected fluid 15 reservoir. In this manner, the ratio of flow rate of carrier fluid through the nozzles and flow rate of injected fluid into the nozzle is controlled, thereby controlling the concentration of the injected fluid in the spray fluid dispensed from the spray nozzle. In view of the above, one embodiment of a system for dispensing controlled amounts of an additive, such as an agrochemical, comprises one or more nozzles or 20 other dispensing devices, each having an internal integrated Venturi therein. The system comprises a first reservoir for holding a carrier fluid. The first reservoir is in fluid communication with a first distribution manifold. The first distribution manifold is also in fluid communication with the one or more dispensing nozzles so that carrier fluid from the first reservoir passes through the one or more nozzles, passing through 25 the Venturis therein. The system further comprises a second reservoir for holding an additive, which may be a liquid, gas, dispersion, suspension or the like. A second distribution manifold is in fluid communication with the second reservoir and with the plurality of dispensing nozzles. In accordance with an embodiment of the present invention, each dispensing 30 nozzle comprises at least one Venturi. Each Venturi comprises at least one induction port that is in communication with the second distribution manifold. In this manner, as the carrier fluid flows through the Venturi, a vacuum is created that draws in the additive for combining with the carrier fluid to form a fluid mixture prior to exiting the nozzle.

-8 5 In one embodiment, both the carrier fluid and the additive are liquids. The system is particularly well suited to combining an additive, such as an agrochemical, with a carrier fluid where the two components have incompatibility issues. For instance, the two components may be immiscible or may have a limited functional life once combined together. In one embodiment, suspended solids may also be contained 10 in one or both of the components. For instance, the carrier liquid and/or the agrochemical may also be a dispersion or suspension. In general, the carrier fluid can be any appropriate carrier for the agrochemical and may be a liquid or a gas. For instance, in one embodiment, the carrier fluid may be water, either alone or in combination with other ingredients. The additive, on the other 15 hand, may be any fluid that provides some type of benefit within the process. The additive, for instance, may be any chemical agent that has an affect on the substrate being sprayed or may be any fluid that facilitates application of the carrier fluid or that enhances one or more ingredients contained in the carrier fluid. As used herein, however, the additive excludes air. As described above, in one embodiment, the 20 additive is an agrochemical. The agrochemical may be any chemical that either provides a benefit to a crop being grown or otherwise facilitates application of the carrier fluid. Examples of agrochemicals that may be dispensed using to the present invention comprise a herbicide, an insecticide, a pesticide, a growth regulator, a desiccant, a defoliant, a fungicide, a rodentacide, a fertilizer, a nutrient stabilizer, a soil 25 conditioner, a root stimulant, a surfactant, a drift inhibitor, a buffer, or mixtures thereof. In general, the agrochemical is combined with the carrier fluid such that the resulting mixture contains the agrochemical in the amount from about 0.5 percent to about 40 percent by weight, or more particularly from about 0.5 percent to about 10 percent by weight. The actual amount of the agrochemical combined with the carrier 30 fluid may depend upon numerous factors. As described above, the second distribution manifold feeds the agrochemical to the Venturis contained in the dispensing nozzles through an induction port. Each dispensing nozzle can comprise a single induction port that is placed in communication with the second distribution manifold or can contain a plurality of induction ports that -9 5 are in communication with the second distribution manifold. In addition to induction ports for the agrochemical, the dispensing nozzles can further comprise gas ports for combining a functionally inert gas, such as air, or a functional gas such as a pesticide or growth regulator or other agrochemical with the fluid mixture. In one embodiment, one or more gas ports may be in communication with the Venturis on the dispensing nozzle 10 for drawing in air to the nozzles. In an alternative embodiment, each dispensing nozzle may comprise a second Venturi. The second Venturi may comprise one or more air ports for combining air with the carrier fluid or with the fluid mixture. The second Venturi, for instance, may be positioned before or after the Venturi that is used to mix the agrochemical with the carrier fluid. 15 In still another embodiment of the present invention, each dispensing nozzle can comprise a plurality of Venturis, where each Venturi is used to inject a separate additive into the carrier fluid. For example, two to five Venturis may be placed in series in order to inject two to five additives into the carrier fluid without any premixing of the additives. This enables easy changes of the relative proportions of the different 20 additives as spraying is performed. The system of the present invention may further comprise various controls for monitoring and adjusting the flow rate of the carrier fluid and/or agrochemical. For example, the first distribution manifold may be in communication with a pumping device and a flow control device for feeding controlled amounts of the carrier fluid to 25 the dispensing nozzles. The flow rate of the agrochemical, in one embodiment, can be at least partially controlled by controlling and adjusting the flow rate of the carrier fluid through the dispensing nozzles. Orifice devices may also be placed upstream of the dispensing nozzles on the second distribution manifold for also controlling the flow rate of the agrochemical. 30 In one embodiment, the first distribution manifold may be placed in communication with a first flow meter and a first pressure transducer, while the second manifold may be placed in communication with a second flow meter and a second pressure transducer. The system can further comprise a controller that is placed in communication with the above devices. The controller, based upon receiving -10 5 information from the first flow meter, the first pressure transducer, the second flow meter, and the second pressure transducer may be configured to adjust the flow rates of the carrier fluid, the agrochemical, or both. In one embodiment, the controller can be placed in communication with a global positioning location and rate map device that may be used to convey information to the 10 controller that may be used in adjusting the flow rates of the carrier fluid, the agrochemical, or both. Similarly, the system may also comprise a crop sensor placed in communication with the controller. The controller, based upon information received from the crop sensor, can then adjust the flow rates of the various components. In these embodiments, the flow rates of the components can be controlled depending upon 15 various conditions in the field and the desired result. In addition to a system, the present invention may also be directed to a method for dispensing controlled amounts of an additive, such as an agrochemical. The method comprises the step of flowing a carrier fluid through a plurality of dispensing nozzles. Each dispensing nozzle comprises a Venturi and an induction port in 20 communication with the Venturi. An agrochemical is fed through the induction ports of the Venturi for mixing with the carrier fluid to form a fluid mixture. The carrier fluid creates a vacuum within each Venturi which draws in the agrochemical into the dispensing nozzle. In accordance with the present invention, the fluid mixture may then be dispensed onto a field. The field, for instance, may be a crop field, an orchard, or the 25 like. In still another embodiment, the ratio of injected fluid to the carrier fluid is actively controlled by an electronic throttling valve in response to electronic control signals from Global Positioning Systems and spray application rate controllers or crop sensors on a mobile spray application vehicle. In this manner, the application rate of an 30 agrochemical can be varied in accordance with the need for the chemical at a particular location at a particular time. Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.

-11 5 BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only: FIG. I is a schematic diagram of an embodiment of the invention comprising a 10 plurality of spray nozzles and liquid injection lines and control and monitoring components for carrier and injection fluid supply systems. FIG. 2 is a schematic diagram of an air induction nozzle with Venturi ports for receiving injected liquid from a supply reservoir. FIG. 3 is a schematic diagram of a nozzle in which a series of Venturi ports are 15 used for inlet of injected fluid and ambient air. FIG. 4 is a graph of the concentration of injected fluid in the total discharged fluid from the spay nozzle for a series of nozzle carrier fluid supply pressures and injection fluid metering plates of different diameters. FIGs. 5A, B are graphs of the spatial distribution of spray liquid flux for air and 20 various liquids injected into the Venturi ports of an air induction nozzle. FIG. 6 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an air induction nozzle operating at different carrier liquid pressures and with varying sized injection metering plates. FIG. 7 is a graph of the spatial distribution of injected liquid within the spray 25 liquid discharged from an air induction nozzle operating at 4 bar carrier liquid pressure and with varying sized injection metering plates and varying fluid properties. FIG. 8 is a graph of the droplet size spectra for spray droplets produced by an air induction nozzle operating at 4 bar carrier liquid pressure and with water injected into the Venturi ports with varying sized orifice metering plates in the injecting supply line. 30 FIG. 9 is a graph of the droplet size spectra for spray droplets produced by an air induction nozzle operating at 4 bar carrier liquid pressure and with various liquids injected into the Venturi ports with a 0.008 inch diameter orifice metering plate in the injecting supply line. FIG. 10 is a graph of the spatial distribution of injected liquid within the spray - 12 5 liquid discharged from an array of 6 Al 1008 air induction nozzles operating at 2 bar carrier liquid pressure, with varying sized injection metering plates and with injection fluid injected into 2 inlets into the Venturi. FIG. 11 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an array of 6 AI 11008 air induction nozzles operating at 2 bar 10 carrier liquid pressure, with varying sized injection metering plates and with injection fluid injected into a single inlet into the Venturi. FIG. 12 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an array of 6 Al 11008 air induction nozzles operating at 2 bar carrier liquid pressure, with a 0.0 10 inch diameter injection metering plate and with 15 injection fluid injected into a single inlet versus 2 inlets into the Venturi. FIG. 13 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an array of 6 Al 11008 air induction nozzles operating at 2 bar carrier liquid pressure, with a 0.020 inch diameter injection metering plate and with injection fluid injected into a single inlet versus 2 inlets into the Venturi. 20 FIG. 14 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an array of 6 Al 11008 air induction nozzles operating at 2 bar carrier liquid pressure, with a 0.041 inch diameter injection metering plate and with injection fluid injected into a single inlet versus 2 inlets into the Venturi. FIG. 15 is a graph of the spatial distribution of injected liquid within the spray 25 liquid discharged from an array of 6 Al 11008 air induction nozzles operating at 2 bar carrier liquid pressure, with a 0.041 inch diameter injection metering plate and with injection fluid injected into a single inlet into the Venturi and with the injection fluid metered using a throttling needle valve to simulate smaller diameter metering orifice plates. 30 FIG. 16 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an array of 6 Al 11006 air induction nozzles operating at 2 bar carrier liquid pressure, with 0.0 10, 0.020 and 0.041 inch diameter injection metering plates and with injection fluid injected into a single inlet into the Venturi. FIG. 17 is a graph of the spatial distribution of injected liquid within the spray - 13 5 liquid discharged from an array of 6 Al 11006 air induction nozzles operating at 2 bar carrier liquid pressure, with a 0.041 inch diameter injection metering plate and with injection fluid injected into a single inlet into the Venturi and with the injection fluid metered using a throttling needle valve to simulate smaller diameter metering orifice plates. 10 FIG. 18 is a graph of the spatial distribution of injected liquid within the spray liquid discharged from an array of 6 Al 11004 air induction nozzles operating at 2 bar carrier liquid pressure, with 0.0 10, 0.020 and 0.041 inch diameter injection metering plates and with injection fluid injected into a single inlet into the Venturi. FIG. 19 is a graph of the spatial distribution of injected liquid within the spray 15 liquid discharged from an array of 6 Al 11004 air induction nozzles operating at 2 bar carrier liquid pressure, with a 0.041 inch diameter injection metering plate and with injection fluid injected into a single inlet into the Venturi and with the injection fluid metered using a throttling needle valve to simulate smaller diameter metering orifice plates. 20 FIG. 20 is a graph of the concentration of injected fluid in the discharged spray liquid from a range of nozzles operating at 2 bar and with a range of injection metering plate diameters. DETAILED DESCRIPTION 25 In general, the here described technology is directed to a system and method for combining controlled amounts of an additive, such as an agrochemical, with a carrier fluid in a fluid dispensing process. More particularly, the present embodiment is directed to using one or more nozzles containing a Venturi through which the carrier fluid flows. Each Venturi comprises an induction port for feeding controlled amounts 30 of the additive into the nozzle. As the carrier fluid flows through the Venturi, a vacuum is created that draws in the additive for combining with the carrier fluid. The Venturi and supporting structure also create turbulent conditions within the nozzle for ensuring that the additive and the carrier fluid are well mixed prior to exiting the nozzle. The present invention is particularly well suited for use in agricultural spraying 35 systems and for combining an agrochemical with a carrier fluid, such as water. Through - 14 5 the use of a Venturi, the additive is combined with the carrier fluid in an at least a semi automatic manner. For example, increasing or decreasing the flow of the carrier fluid can increase or decrease the flow of the additive while maintaining the concentration of the additive in the resulting fluid mixture substantially constant. As will be described in greater detail below, further controls can be placed into the system for ensuring that the 10 desired ratio of components exits the nozzle. Of particular advantage, the additive and the carrier fluid are combined within the nozzle just prior to being dispensed from the system. Thus, incompatible materials can be combined and dispensed in a relatively simple manner. Having the carrier fluid and additive being combined in the nozzle, also allows for rapid adjustments in the 15 concentration of the additive and the resulting mixture as environmental conditions change during the application process. Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus and system generally shown in FIG. I through FIG. 3. It will be appreciated that the apparatus may vary as to configuration and as to 20 details of the parts, and that the methods may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein. FIG. 1 generally shows a schematic diagram of one embodiment of a system according to the present invention. FIG. 2 shows details of a portion of the system, comprising a nozzle with embedded Venturi. FIG. 3 shows a more complex multistage 25 nozzle with a pair of Venturis. In FIG. 1, a system 24 is shown that has a plurality of induction nozzles 10 that are arranged in a parallel manner (or other desired orientation) in an array 26. While six nozzles are shown, in practice the number can vary from a single nozzle up to a large number of nozzles. Each nozzle 10 is supplied at one end thereof with carrier fluid via 30 a manifold 12 that is pressurized by a pumping device 14 withdrawing fluid from a carrier fluid reservoir 16. The carrier fluid supply circuit may comprise a metering and control (throttle) valve 18 that may be manually or remotely adjusted to achieve a desired flow rate or pressure of the carrier fluid. The carrier fluid supply circuit may. also comprise a flow meter 20 and a pressure transducer 22 that can provide control - 15 5 information to a controller 28 that can be hard wired or part of a remote control system. The connection of controller 28 to the rest of system 24 is represented by the arrows 42. The controller 28, for instance, may be any suitable programmable logic unit, such as a microprocessor or a computer. Each nozzle 10 is also supplied with a fluid or additive to be injected into the 10 carrier fluid stream. The injected fluid or additive is supplied to the nozzles from a manifold 30 to which the additive is supplied from a reservoir 32. The additive supply circuit may comprise a metering and control (throttle) valve 34 that may be manually or remotely adjusted to achieve a desired flow rate or pressure of the injected fluid. The additive supply circuit may also comprise a flow meter 36 and a pressure transducer 38 15 that provide control information to the controller 28. The motive force for the propulsion of the additive is mainly supplied by Venturi passages within the induction nozzles 10 but may be supplemented by a pumping device. In FIG. 1, the motive force for the injection is supplied by the Venturi passages within the induction nozzles 10 but an optional pump 88 may be added to the additive fluid supply circuit to increase fluid 20 flow. The additive supply lines to the nozzles 10 may contain metering orifices 40 to provide a controlled resistance to fluid flow. Additionally, the supply lines may contain a one-way flow or "check" valve 44 that allows fluid flow toward the nozzle 10 but not in the reverse, i.e., from the nozzle 10 back to the manifold 30 direction. This prevents 25 unintended or undesirable changes in manifold pressure should a nozzle 10 malfunction. In operation, a carrier fluid, which may comprise a mixture of different components, is placed into the carrier reservoir 16 and propelled by the pumping device 14 to nozzles 10. The flow rate of the carrier fluid into nozzles 10 can be controlled by common means such as the adjustment of the pump rotation speed or by modulation of 30 the throttling valve 18. The flow rate of carrier fluid from the nozzles 10 will typically follow the standard square root relationship wherein the volumetric flow rate of carrier fluid as measured by the flow meter 20 will be proportional to the square root of the pressure indicated by the pressure transducer 22. As carrier fluid flows through nozzle 10, it passes through an internal Venturi passage way (shown in FIG. 2). The carrier - 16 5 fluid flow through the Venturi will induce a vacuum on inlet ports to the Venturi to which the additive supply is connected. The vacuum will draw the injection fluid through the manifold 30 and into the nozzle 10. The flow rate of injected additive into the carrier fluid flow is controlled by the flow rate of the carrier fluid and can also be controlled by the metering orifices 40. This 10 provides a passive, simple means for metering the concentration of injected fluid into the carrier fluid. Alternatively, the needle or similar throttling valve 34 can be adjusted to control the flow rate of injected fluid into the nozzles 10. The pressure measured by the pressure transducer 38 and the volumetric flow rate measured by flow meter 36 can be 15 transmitted to the controller 28, which in turn can make adjustments as needed. The mixed carrier/additive fluid exits the distal ends of nozzles 10 in a spray 46 which is applied to a spray application area 48. Spray application area 48 is typically an agricultural field. By selecting the output spray pattern of nozzles 10 and the configuration of array 26, desired coverage of sprays 46 over area 48 can be obtained. 20 The induction nozzles 10 as shown in FIG. I are shown in more detail in FIG. 2. Carrier fluid enters the nozzle 10 at a nozzle inlet 52 at one end thereof and passes through an internal Venturi 50 to a spray tip 54 at the distal end thereof. The carrier fluid passage through the Venturi 50 produces a vacuum at the Venturi induction ports 56. In this embodiment, the Venturi 50 is used to induce an injection additive flow 25 through Venturi ports 56 into the carrier fluid dispensed by the nozzle 10. The general configuration of nozzle 10 is well known in the art, as exemplified by the air induction liquid spray nozzle assembly of PCT Published International Application WO 2006/002300, incorporated herein by reference in its entirety. Nozzle 10 generally comprises a nozzle body 58 and a nozzle body insert 60 that is removably 30 engaged within body 58. Insert 60 defines therethrough a fluid flow passage that comprises the carrier inlet 52, a metering orifice 60, and the Venturi 50, which is part of the downstream expansion section 62. Expansion section 62 ends in outwardly flared conical section 64 that communicates with expansion chamber 66 in body 58. Expansion chamber 66 is next to mixing chamber 68 in spray tip 54 which is also - 17 5 removably engaged within body 58 at the distal end thereof. Mixing chamber 68 communicates with outlet 70 in spray tip 54. An aperture 80 in the end 82 of nozzle body 58 is aligned with channel 70 in tip 54 so that fluid is sprayed out of nozzle 10. Venturi 50 comprises a pair of transverse passage ways or ports 72 that extend perpendicularly from the flow passage through insert 60. Nozzle body 58 comprises 10 induction ports 56 formed therethrough. Venturi ports 72 in insert 60 are aligned with induction ports 56 in body 58. An inlet chamber 74 is defined between insert 60 and body 58, and Venturi ports 72 and induction ports 56 communicate with this inlet chamber 74. Additive supply lines 76 are connected to the injection ports 56. The additive fluid supply circuit of FIG. I is not repeated in FIG. 2. Instead, supply lines 76 15 are shown as drawing additive injection fluid 78 from reservoir 32, with metering orifices 40 at the supply line intakes. The invention can be implemented with any suitable supply configuration. In operation, the flow of carrier fluid through Venturi 50 produces a pressure drop or vacuum that is applied through ports 72 to additive fluid 78 in supply lines 76, i.e. the pressure difference causes fluid from reservoir 32 to flow 20 through supply lines 76, ports 56, chamber 74, and ports 72 to the flow channel within nozzle 10 where it mixes with the carrier fluid. FIG. 2 shows two injection fluid inlet ports 56 into the nozzle Venturi 50. Alternatively, one port may be connected to the injection fluid flow and the other port may comprise a gas port for drawing in air to control droplet size. Alternatively, the 25 nozzle may be fabricated so that there is only one port into the Venturi. An alternative embodiment of the nozzle 10 is shown in FIG. 3. In this embodiment, a series of two Venturis 50 and 150 are included in the nozzle assembly. The carrier fluid enters the nozzle in the manner as in FIG. 2, at one end of the nozzle at inlet 52. As the carrier fluid passes through the first Venturi 50, the fluid to be injected 30 is drawn into the Venturi. The carrier fluid and the injection fluid mix and the internal pressure recovers as the fluid passes downstream from the Venturi 50. The mix of carrier and injected fluid then passes through a second Venturi 150 where ambient air is induced to effect the desired modification in the droplet size spectrum of the spray to be dispensed. In particular, nozzle 10 comprises two gas ports 156 that are used to draw in - 18 5 the ambient air. Alternatively, the Venturi 150 that is used to draw in air may be positioned upstream from the Venturi 50 which is used to draw in the additive, i.e. Venturi 50 and Venturi 150 may be reversed or supply lines 76 may be connected to ports 156 instead of ports 56. It will be understood by those skilled in the art that multiple Venturi passageways in series could be used to introduce a number of injection 10 fluids into a single spray nozzle. As described above, the system and method of the present invention is particularly well suited for use in the agricultural field. The system and method, however, can also be used in other spray systems. In this regard, the additive that is combined with the carrier fluid can comprise a limitless variety of different chemicals, 15 compounds, species, gases, dispersions, suspensions, and the like. In one application, the additive combined with the carrier fluid is an agrochemical. The agrochemical, for instance, may be an herbicide, an insecticide, a pesticide, a nematicide, a growth regulator, a desiccant, a defoliant, a fungicide, a rodentacide, a fertilizer, a nutrient stabilizer, a soil conditioner, a root stimulant, a 20 surfactant, a drift inhibitor, a buffer, or mixtures thereof. As described above, in one embodiment, each nozzle may comprise a plurality of Venturis for combining different additives at each Venturi with the carrier fluid. The carrier fluid can be any suitable fluid capable of being combined with the one or more additives. The carrier fluid may be a gas, but for most applications, is a 25 liquid. In one embodiment, for instance, the carrier fluid is water. Water, for instance, may be used alone as the carrier fluid or may be premixed with various other ingredients and additives that may be more compatible with the carrier fluid than the additive being injected at the one or more nozzles. When comprising only water, the reservoir for the carrier fluid may be any suitable water source, such as a city water 30 source. The amount of additive combined with the carrier fluid may depend upon various factors including the type of additive used, the particular application, and the desired result. In general, for instance, the additive can be combined with the carrier fluid in the amount of from about 0.5 percent to about 10 percent by weight. Greater or -19 5 lesser amounts, however, are possible. The system of the present invention, such as the embodiment shown in FIG. 1, can be manually operated, semi-automatic, or fully automated. For instance, various different controls can be included in the system so that flow rates can be adjusted manually or can be done automatically. As described above, for instance, a controller 10 28 can be connected to all of the system components and, based on information received from the components, can control other components in order to adjust flow rates and component ratios. In one embodiment, controls can also be included for varying the flow rate through each of the nozzles 10. In particular, in some embodiments, it may be desirable to alter the flow rate between the individual nozzles. In this regard, the nozzle 15 10 can comprise or be in communication with a valve for adjusting individual flow rates. Valves 80 between manifold 12 and each valve 10 for individual control of the flow in each nozzle 10 are representative. Controller 28 can be placed in communication with a global positioning location and rate map device 82 that may be used to convey information to the controller that 20 may be used in adjusting the flow rates of the carrier fluid, the agrochemical, or both. Similarly, the system may also comprise a crop sensor 84 placed in communication with the controller 28. The controller 28, based upon information received from the crop sensor 84, can then adjust the flow rates of the various components. The crop sensor 84 may be stationary, i.e. positioned at a particular location, or may be mobile, e.g. 25 mounted on a spray application vehicle 86 (on which the system 10 may also be mounted). In these embodiments, the flow rates of the components can be controlled depending upon various conditions in the field and the desired result. The invention may be better understood with reference to the accompanying examples, which are intended for purposes of illustration only and should not be 30 construed as in any sense limiting the scope of the present invention as defined in the claims appended hereto. Example 1 The nozzle used in this example was a 110 degree fan angle, Venturi flat fan - 20 5 nozzle (AI 11004, TeeJet, Spraying Systems, Inc.). Inserted into the two air inlet ports of the integrated Venturi were barbed connectors leading to 50 cm of plastic tubing (1.6 mm i.d.). The plastic tubing terminated into a standard threaded nozzle body assembly (CP1322 % TT, TeeJet, Spraying Systems, Inc.) into which a range of orifice metering plates were installed. The metering plates were standard commercial components (CP 10 4916 Series, TeeJet, Spraying Systems, Inc.) with orifice diameters of 0.20, 0.38, 0.76, 1.54 and 3.05 mm (Plate Nos. 8, 15, 30, 61 and 120, respectively, Spraying Systems, Inc.). The carrier liquid, supplied to the liquid inlet of the nozzle, for all experiments was de-ionized water and the injected liquids, supplied to the air induction ports, were de-ionized water, a 0.25% v/v surfactant solution (Triton X-100, Fisher Scientific) in 15 de-ionized water and a 0.25% v/v polymer solution (polyacrylamide, Target LC, Loveland Chemicals, Inc.) in de-ionized water. Flow rates of injected liquid into the carrier liquid were determined by adding a tracer salt (NaCl) to the injected fluid to create a 10,000 or 15,000 mg L concentration. The concentration of the tracer in the discharged spray from the nozzle was measured 20 along with the total flow rate of liquid from the nozzle. Concentration was measured using a calibrated conductivity probe (Model TDS Testrl, LaMotte). With the tracer concentration of the discharged fluid and the injected fluid being known, along with the total flow rate from the nozzle and the zero concentration of tracer in the carrier fluid, conservation of mass of tracer could be used to determine the flow rate of injected fluid. 25 Mass distribution, viz., the "spray pattern" from the nozzle was determined by collecting spray discharge in 125 ml bottles positioned at 9 cm spacing in an array along the axis of the emitted spray fan. Collected mass was measured using an electronic scale. Similarly, distribution of injected fluid across the spray pattern was measured by preparing a 1000 ppb solution of brilliant sulfaflavine (BSF) that was used as the 30 injection fluids as described earlier. An array of collection bottles was placed at 9 cm spacing along the spray pattern. The collected samples were analyzed using a fluorometer (VersaFluor 100-120-200V, Bio-Rad) that had been calibrated over a range of I to 300 ppb of the tracer. Spray distribution and injected liquid uniformity were measured at a nozzle-to-sample plane distance of 50 cm and graphed for visual -21 5 assessment and analysis. Spray droplet size spectra were analyzed using a laser diffraction instrument (Malvern Spraytec 2600, 450 mm lens) positioned on the nozzle center line and 50 cm below the nozzle. The system was operated in the model independent mode, time history setting and data were collected at 1 kHz for 60 sec or until the distribution 10 appeared to be stable. Media and particulate refractive indices were 1.00 + 0.00i and 1.33 + 0.00i, respectively. The degree to which the nozzle could induce injection liquid flow into the carrier fluid of the nozzle was determined. When the liquid supply was connected to the nozzle inlet ports, the Venturi vacuum was sufficient to produce a concentration of over 15 30% v/v of injected liquid in the nozzle discharge, exceeding typical application rates of most concentrated pesticide formulations. The apparatus was then modified to allow the installation of standard, commercial metering orifices into the induction flow lines. A range of metering orifices (Nos. 8, 15 and 30) were used. These orifice plates produced injection rates of approximately 3 to 18% concentration. Observed data are 20 presented in FIG. 4 and indicate that the concentration of injected material tends to remain constant as the supply pressure and corresponding volumetric flow rate of carrier liquid vary over a typical operating range. This indicates that the invention can be used as a passive injection rate controller to maintain a constant concentration as the carrier fluid flow rate through a nozzle is varied. 25 The effects of the injected fluid on the pattern or spatial distribution of spray from the nozzle was investigated. Example results are shown in FIG. 5A and FIG. 5B. The injection of various fluids did not significantly affect the distribution of the spray pattern. When compared to the typical air induction pattern, fluid injection patterns were indistinguishable from the typical. 30 With the mass distribution of the emitted spray unaffected by the injection of fluids into the Venturi ports of the nozzle, the distribution of the injected liquid across the spray pattern was determined. This is important in that the active ingredient of an agricultural spray application would typically be the injected material and the distribution of active ingredient must be uniform across the spray pattern. Additionally, - 22 5 the result provided insight into the degree of mixing provided by the relatively short transit distance and residence time of the fluid passing from the Venturi ports to the nozzle exit orifice. Results are shown in FIG. 6 and FIG. 7. Results for water injection liquid and a range of metering plate diameters and carrier liquid supply pressures are shown in FIG. 10 6. The results indicate that the injected liquid is uniformly mixed within the carrier fluid and discharged uniformly across the spray pattern. In FIG. 7, the results shown focus on the lower concentration injections rates (Metering plate Nos. 8 and 15) and for the three injection liquids of water, surfactant solution and polymer solution. The observed uniformity is high and illustrates the validity of the design. 15 The effects of fluid injection on the droplet size spectra produced by the nozzle when the air induction ports were used as liquid inlet ports was determined. It was anticipated that the modification to the nozzle operation by replacing the induced air with injected fluid would result in a change in droplet size spectra. This was based on recognition that the purpose of the Venturi-driven air induction was to alter the 20 atomization characteristics, and the resulting droplet size spectrum, of the spray from the nozzle. Moreover, it was further expected that the addition of fluid to the nozzle air inlets would most likely decrease the overall droplet size spectra. Results from the experiments are shown in FIG. 8 and FIG. 9. In FIG. 8, the effects of injecting water into the Venturi ports on the resulting droplet size are realized 25 as both an overall decrease in the droplet size spectra and a change in the shape of the spectra. For example, compared to the air induction with an average v.m.d. of 405 tim, the water injection with metering plates Nos. 8, 15 and 30 produced average v.m.d. values of 298, 269 and 266 rim, respectively. In FIG. 9, the effects of injected fluid on the resulting droplet size spectra are 30 illustrated. For the smallest metering plate (i.e., No. 8), the droplet size spectra for air, water, surfactant solution and polymer solution are shown. An observable effect of fluid type on droplet size spectra is noted and the general trend of decreasing droplet size with surfactant solution and increased size with polymer is seen. Air injection produces the largest size spectra.

- 23 5 The results observed and presented in this example established that: the Venturi air inlets of an air induction spray nozzle produce sufficient vacuum to provide the necessary power to pump useful rates of common liquids into the spray nozzle carrier fluids; the rate of liquid injection can be established and maintained at commercially useful concentrations of approximately 3 to 18 % through the use of metering restrictor 10 plates with diameters in the 0.2 to 0.7 mm range and that flow rates of injected fluid are affected by fluid properties; injection of common spray liquids, containing surfactants at the concentration of 0.25% v/v and polymers at similar concentrations does not significantly affect the spray nozzle distribution pattern; at a typical operating carrier fluid supply pressure of 2 to 4 bar, injection of fluids into the Venturi ports results in a 15 uniform mixing and discharge of the injected fluid across the spray pattern; and, injection of fluid, rather than air, into the Venturi air ports of an air induction nozzle significantly alters the droplet size spectra of the emitted spray; it tends to produce smaller droplets and create a more bimodal size distribution. 20 Example 2 In this example an array of 6 nozzles was fabricated in a linear spray boom with 20 inches between each nozzle. A system of spray collectors was devised to capture the emitted spray on a plane 20 inches below the exit tips of the spray nozzles. The spray discharge was collected in 1.5 inch increments along the plane. This provided a 25 measure of the uniformity of the spray mix along the entire 120 inch spray pattern created by the 6-nozzle spray boom. Salt tracer was added to the injected fluid as discussed in Example 1. The measurement techniques used in Example I were also used for this example. The system was fabricated as illustrated in FIG. 1. The nozzles were Al 11008 30 nozzles (Spraying Systems, Inc.) and operated at a carrier liquid pressure of 2 bar. In the first set of tests, the nozzles were configured similarly as shown in FIG. 2 with an injection line directed to each side of the Venturi inlet. The test orifices were Nos. 10, 20 and 41 as described in Example 1. The resulting measurements of injected liquid concentration across the a 2 m - 24 5 section of the central spray pattern is shown in FIG. 10. The result show the uniformity of the pattern and the effect of changing the metering plate diameter. In a subsequent test, the injection flow system was altered to use only one injection port on each nozzle. The remaining port was blocked off to liquid or air inlet. This test was to determine the feasibility of a more simple design in which each nozzle 10 would be supplied with 1, rather than 2, inlet injection liquid inlet lines and orifice metering plates. The results of the "single port" experiment are shown in FIG. 11 and reveal that uniformity of distribution of injected liquid was maintained. FIG. 12, FIG. 13 and FIG. 14 show comparisons of single versus double port injection and establish that single 15 port injection is suitable for practice of the invention. Example 3 It is desirable to have an active control over the flow rate of the injected liquid into the Venturi passage in the nozzle. This would provide a means for adjusting the 20 application rate of active ingredient contained in the injected liquid. In this example, the system shown in FIG. I was tested. A controllable needle metering valve was used to alter the injection rate of liquid into the nozzles. A No. 41 metering orifice plate was installed as orifice plate assembly. In the first test, 6 Al 11008 nozzles were operated as described in Example 2. 25 Spray tracer fluid was used as in Example 2. However, rather than manually changing the orifice plates to adjust injection flow rate, the needle valve was manually closed until the flow rate on flowmeter was observed to match that obtained then orifice plates 10 and 20 were installed at location. The results are shown in FIG. 15. Injection rates and resulting spray 30 concentrations equivalent to those achieved by replacing the metering plates were achieved and spray uniformity was maintained. The test described above was repeated after the nozzles had been changed from AI 11008 nozzles to AI 11006 nozzles. The Al 11006 nozzles have approximately 25% less flow capacity than the Al 11008 nozzles.

-25 5 The results of the Al 11006 nozzle tests are shown in FIG. 16 and FIG. 17. The results show similar trends to those from the Al 11008 nozzle tests. The metering valve can be used to control the spray concentration and uniformity is maintained. The test described above was repeated after the nozzles had been changed from Al 11008 nozzles to Al 11004 nozzles. The Al 11004 nozzles have approximately 50% 10 less flow capacity than the Al 11008 nozzles. The results of the Al 11004 nozzle tests are shown in FIG. 18 and FIG. 19. The results show similar trends to those from the Al 11008 and Al 11006 nozzle tests. The metering valve can be used to control the spray concentration and uniformity is maintained. 15 The test data from the evaluations in Example 3 were collected and re-analyzed to establish the relationship between orifice plate diameter and resulting concentration of injected fluid in the discharged spray when the nozzles were operated at 2 bar. The results are shown in FIG. 20 and illustrated how orifice diameter affects the injection flow rate. 20 The present invention thus provides a system and method of using embedded Venturi passageways within nozzles to propel and mix injected liquid into a carrier stream of spray liquid. Further, the passive and active flow control characteristics are established and shown as a means to improve the application of agrochemicals from mobile equipment. 25 The invention is particularly suited for use with agricultural and industrial sprayers, however, it will be understood that the apparatus and system can be used in any application or system that requires controlled liquid sprays. As a short overview, the foregoing description has disclosed the following concepts. 30 Concept 1. A system for dispensing controlled amounts of an additive mixed with a carrier, comprising: one or more dispensing and mixing nozzles, each nozzle comprising a Venturi and an induction port in communication with the Venturi; - 26 5 a carrier fluid supply connected to each nozzle; and an additive fluid supply connected to the induction port of each nozzle; wherein carrier fluid flow through the Venturi in the nozzle causes additive fluid to be drawn into the nozzle and mixed with the carrier fluid prior to exiting the nozzle. 10 Concept 2. The system of concept 1, wherein each nozzle is an air induction nozzle. Concept 3. The system of concept 1, further comprising a control system for controlling the flow of the additive fluid, the carrier fluid, or both to each nozzle. 15 Concept 4. The system of concept 1: wherein the carrier fluid supply comprises a carrier fluid reservoir for holding the carrier fluid and a carrier fluid supply circuit connecting the carrier fluid reservoir to each nozzle; and 20 wherein the additive fluid supply comprises an additive fluid reservoir for holding the additive fluid and an additive fluid supply circuit connecting the additive fluid supply to the induction port of each nozzle. Concept 5. The system of concept 4: 25 wherein the carrier fluid supply circuit comprises a first pump, a first metering and control valve, a first flow meter, a first pressure transducer, and a carrier fluid distribution manifold, arranged in series, the carrier fluid distribution manifold being connected to each nozzle; and wherein the additive fluid supply circuit comprises a second metering and control 30 valve, a second flow meter, a second pressure transducer, and an additive fluid distribution manifold, arranged in series, the additive fluid distribution manifold being connected to the induction port of each nozzle.

- 27 5 Concept 6. The system of concept 5, further comprising a control system for controlling the flow of the additive fluid, the carrier fluid, or both to each nozzle. Concept 7. The system of concept 6, wherein the control system comprises a controller in communication with the first and second flow meters and the first and 10 second pressure transducers for receiving information therefrom, and in communication with the first pump, and the first and second metering and control valves for controlling the flow of the carrier fluid, the additive fluid, or both in response thereto. Concept 8. The system of concept 1, wherein each nozzle further comprises a gas 15 port in communication with the Venturi and with ambient atmosphere so that carrier fluid flow through the Venturi causes air to also be drawn into the nozzle and mixed with the carrier and additive fluids. Concept 9. The system of concept 1, wherein each nozzle comprises a second 20 Venturi and a gas port in communication with the second Venturi and with ambient atmosphere for drawing air into the nozzle for mixing with the carrier and additive fluid mixture. Concept 10. The system of concept 4, wherein the additive fluid supply circuit 25 further comprises a metering orifice for controlling additive fluid flow to the induction port of each nozzle. Concept 11. The system of concept 4, wherein the carrier fluid supply circuit comprises a pump and a flow control device for feeding controlled amounts of the 30 carrier fluid to each nozzle. Concept 12. The system of concept 3, wherein the control system comprises a controller and at least one of a global positioning location and rate map device and a crop sensor in communication with the controller, the controller receiving information -28 5 therefrom, and based thereon adjusting the flow rates of the carrier fluid, the additive fluid or both. Concept 13. The system of concept 1, wherein the carrier fluid supply and additive fluid supply each comprise a liquid supply or gas supply or combinations thereof. 10 Concept 14. The system of concept 1, wherein the additive fluid supply is a supply of an agrochemical. Concept 15. A method for dispensing controlled amounts of an additive mixed 15 with a carrier, comprising: providing a dispensing and mixing nozzle having an embedded Venturi therein and an induction port in communication with the Venturi; connecting an additive fluid supply to the induction port of the nozzle; flowing a carrier fluid through the Venturi in the nozzle, thereby causing a pressure 20 drop or vacuum that draws additive fluid into the Venturi and mixes the additive fluid with the carrier fluid; and dispensing the mixed carrier fluid and additive fluid from the nozzle. Concept 16. The method of concept 15 further comprising controlling the flow rate 25 of at least one of the carrier fluid and the additive fluid. Concept 17. The method of concept 15, further comprising providing a gas port in the nozzle, the gas port communicating with the Venturi and with the ambient atmosphere, so that air is also drawn into the carrier fluid and additive fluid mixture. 30 Concept 18. The method of concept 15, further comprising providing a second embedded Venturi in the nozzle, and a gas port communicating with the second Venturi and with the ambient atmosphere, to draw air into the nozzle.

- 29 5 Concept 19. The method of concept 15, wherein the carrier fluid and the additive fluid are liquids or gases or combinations thereof. Concept 20. The method of concept 15, wherein the additive fluid is an agrochemical selected from the group consisting of an herbicide, an insecticide, a 10 pesticide, a growth regulator, a desiccant, a defoliant, a fungicide, a rodentacide, a fertilizer, a nutrient stabilizer, a soil conditioner, a root stimulant, a surfactant, a drift inhibitor, a buffer, or mixtures thereof. Concept 21. In a spraying system having a nozzle with an internal Venturi and an 15 air inlet to the Venturi, and a carrier fluid supply connected to the nozzle, the improvement comprising an additive fluid supply connected to the air inlet for mixing an additive fluid drawn into the nozzle by the Venturi effect with a carrier fluid flowing through the nozzle. 20 Concept 22. In the spraying system of concept 21: the additive fluid supply comprising means for controlling the flow of additive fluid to the nozzle; and the carrier fluid supply comprising means for controlling the flow of carrier fluid to the nozzle. 25 Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other 30 embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." All structural, chemical, and functional equivalents to the elements of the above-described preferred - 30 5 embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present 10 disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase "means for." As a final summary, the present technology might be described as follows. A 15 system and method for combining an additive with a carrier fluid in a spray nozzle. The carrier fluid is fed to one or more nozzles that comprise an embedded Venturi. The Venturi comprises an induction port connected to an additive supply. As the carrier fluid flows through the nozzle, the flow creates a vacuum or suction force that draws in the additive. Of particular advantage, the concentration of the additive combined with 20 the carrier fluid can be maintained constant even if the flow rate of the carrier fluid varies. The system and process are particularly well suited for spraying fields, such as crop fields or orchards, with an agrochemical. Throughout the specification, including the claims, where the context permits, the term "comprising" and variants thereof such as "comprises" or "comprising" are to 25 be interpreted as including the state of integer or integers without necessarily excluding any other integers.

Claims (24)

1. A system for dispensing controlled amounts of an additive mixed with a carrier, comprising: 10 one or more dispensing and mixing nozzles, each nozzle comprising a Venturi and an induction port in communication with the Venturi; a carrier fluid supply connected to each nozzle; and an additive fluid supply connected to the induction port of each nozzle; wherein carrier fluid flow through the Venturi in the nozzle causes additive fluid 15 to be drawn into the nozzle and mixed with the carrier fluid prior to exiting the nozzle.

2. The system of claim 1, wherein each nozzle is an air induction nozzle.

3. The system of claim 1 or claim 2, further comprising a control system for 20 controlling the flow of the additive fluid, the carrier fluid, or both to each nozzle.

4. The system of anyone of the preceding claims: wherein the carrier fluid supply comprises a carrier fluid reservoir for holding the carrier fluid and a carrier fluid supply circuit connecting the carrier fluid reservoir to 25 each nozzle; and wherein the additive fluid supply comprises an additive fluid reservoir for holding the additive fluid and an additive fluid supply circuit connecting the additive fluid supply to the induction port of each nozzle. 30

5. The system of claim 4: wherein the carrier fluid supply circuit comprises a first pump, a first metering and control valve, a first flow meter, a first pressure transducer, and a carrier fluid distribution manifold, arranged in series, the carrier fluid distribution manifold being connected to each nozzle; and - 32 5 wherein the additive fluid supply circuit comprises a second metering and control valve, a second flow meter, a second pressure transducer, and an additive fluid distribution manifold, arranged in series, the additive fluid distribution manifold being connected to the induction port of each nozzle. 10

6. The system of claim 5, further comprising a control system for controlling the flow of the additive fluid, the carrier fluid, or both to each nozzle.

7. The system of claim 6, wherein the control system comprises a controller in communication with the first and second flow meters and the first and second 15 pressure transducers for receiving information therefrom, and in communication with the first pump, and the first and second metering and control valves for controlling the flow of the carrier fluid, the additive fluid, or both in response thereto.

8. The system of any one of the preceding claims, wherein each nozzle 20 further comprises a gas port in communication with the Venturi and with ambient atmosphere so that carrier fluid flow through the Venturi causes air to also be drawn into the nozzle and mixed with the carrier and additive fluids.

9. The system of any one of the preceding claims, wherein each nozzle 25 comprises a second Venturi and a gas port in communication with the second Venturi and with ambient atmosphere for drawing air into the nozzle for mixing with the carrier and additive fluid mixture.

10. The system of any one of claims 4 to 7, wherein the additive fluid supply 30 circuit further comprises a metering orifice for controlling additive fluid flow to the induction port of each nozzle. - 33 5

11. The system of any one of claims 4 to 7, wherein the carrier fluid supply circuit comprises a pump and a flow control device for feeding controlled amounts of the carrier fluid to each nozzle.

12. The system of claim 3, wherein the control system comprises a controller 10 and at least one of a global positioning location and rate map device and a crop sensor in communication with the controller, the controller receiving information therefrom, and based thereon adjusting the flow rates of the carrier fluid, the additive fluid or both.

13. The system of any one of the preceding claims, wherein the carrier fluid 15 supply and additive fluid supply each comprise a liquid supply or gas supply or combinations thereof.

14. The system of claim 1, wherein the additive fluid supply is a supply of an agrochemical. 20

15. A method for dispensing controlled amounts of an additive mixed with a carrier, comprising: providing a dispensing and mixing nozzle having an embedded Venturi therein and an induction port in communication with the Venturi; 25 connecting an additive fluid supply to the induction port of the nozzle; flowing a carrier fluid through the Venturi in the nozzle, thereby causing a pressure drop or vacuum that draws additive fluid into the Venturi and mixes the additive fluid with the carrier fluid; and dispensing the mixed carrier fluid and additive fluid from the nozzle. 30

16. The method of claim 15 further comprising controlling the flow rate of at least one of the carrier fluid and the additive fluid. - 34 5

17. The method of claim 15 or claim 16, further comprising providing a gas port in the nozzle, the gas port communicating with the Venturi and with the ambient atmosphere, so that air is also drawn into the carrier fluid and additive fluid mixture.

18. The method of any one of claims 15 to 17, further comprising providing a 10 second embedded Venturi in the nozzle, and a gas port communicating with the second Venturi and with the ambient atmosphere, to draw air into the nozzle.

19. The method of any one of claims 15 to 18, wherein the carrier fluid and the additive fluid are liquids or gases or combinations thereof. 15

20. The method of any one of claims 15 to 19, wherein the additive fluid is an agrochemical selected from the group consisting of an herbicide, an insecticide, a pesticide, a growth regulator, a desiccant, a defoliant, a fungicide, a rodentacide, a fertilizer, a nutrient stabilizer, a soil conditioner, a root stimulant, a surfactant, a drift 20 inhibitor, a buffer, or mixtures thereof

21. In a spraying system having a nozzle with an internal Venturi and an air inlet to the Venturi, and a carrier fluid supply connected to the nozzle, the improvement comprising an additive fluid supply connected to the air inlet for mixing an additive 25 fluid drawn into the nozzle by the Venturi effect with a carrier fluid flowing through the nozzle.

22. In the spraying system of claim 21: the additive fluid supply comprising means for controlling the flow of additive 30 fluid to the nozzle; and the carrier fluid supply comprising means for controlling the flow of carrier fluid to the nozzle. - 35 5

23. A system for dispensing controlled amounts of an additive mixed with a carrier substantially as described herein, with reference to the accompanying drawings.

24. A method for dispensing controlled amounts of an additive mixed with a carrier substantially as described herein, with reference to the accompanying drawings. 10