Hydraulic Nozzles Research Articles

Spray Outputs from a Variable-Rate Sprayer Manipulated with PWM Solenoid Valves

Abstract. Pressure fluctuations from air-assisted orchard sprayers can cause nozzles to discharge inaccurate flow rates during variable-rate spray applications. Variations in total flow rate discharged from 40 nozzles, each coupled with a pulse-width-modulated (PWM) solenoid valve, were determined for a variable-rate air-assisted sprayer. Variables for the total flow rate measurements were number of active nozzles ranging from 1 to 40 and PWM duty cycle ranging from 10% to 100%. Experiments were conducted under conditions with and without operating pressure adjustments. Under the no-pressure-adjustment condition, the operating pressure in the spray line was not adjusted for compensation when either the number of active nozzles or PWM duty cycle was changed. Under the pressure-adjustment condition, the operating pressure was adjusted to retain at 242 kPa. The total flow rate increased as duty cycle and/or number of active nozzles increased under both pressure conditions. However, the operating pressure in the spray line dropped considerably as either the number of active nozzles or duty cycle increased under the no-pressure-adjustment condition, resulting in significant lower total flow rates compared to the pressure-adjustment condition. The differences in total flow rates between the two pressure conditions increased as duty cycle and number of active nozzles increased. To improve future intelligent sprayer accuracy, two-variable regression equations were established to predict and control total flow rates with different duty cycles and numbers of active nozzles operated simultaneously. Keywords: Flow control, Flow rate, Hydraulic nozzle, Pesticide, Precision sprayer.

Droplet spectrum of a spray nozzle under different weather conditions

The application of pesticides is always susceptible to losses through evaporation and drift of the spray droplets. With these losses, a smaller amount of pesticide reaches the target, possibly impairing the efficiency of phytosanitary control. Due to these concerns, the aim of this study was to evaluate the interference of weather conditions in the droplet spectrum produced by hydraulic spraying. To carry out the work, it was necessary to build an experimental system. This consisted of a laser particle-size analyser, hydraulic nozzle (Jacto JSF 11002), stationary sprayer, gas heater, wind tunnel, climate chamber (with the aim of maintaining the internal psychrometry similar to that of the air exiting the wind tunnel), collector, and temperature and RH sensors. The weather conditions for the study included vapour pressure deficits (VPD) of 5, 9.4, 20, 30.6 and 35 hPa, and air velocities of 2, 3.6, 7.4, 11.2 and 12.8 km h-1. A Rotatable Central Composite Design was used, and the data related using Response Surface Methodology. The wind caused such a sharp drift in the fine droplets, that it greatly affected the behaviour of the entire droplet spectrum, as well as hiding the effect of the VPD. However, the conclusion is that drift and evaporation both act on the coarser droplets.

Characterization of Biological Pesticide Deliveries through Hydraulic Nozzles

Abstract. Increased use of biopesticides has spurred demand for efficient and effective delivery systems. To this goal, laboratory tests were conducted to investigate six different classes of biopesticides discharged from five different types of flat-fan nozzles, each with three flow capacities. The biopesticide classes were horticultural oil insecticide (HOI), bacterial biofungicide (BBF), botanical extract bio-insecticide (BEBI), liquid fungal bio-insecticide (FBI-ES), wettable powder fungal bio-insecticide (FBI-WP), and mineral salt biofungicide (MSBF). Droplet size distribution, spray pattern width, spray deposition, and coverage on plant leaves and water-sensitive paper (WSP) were the spray parameters tested. These parameters varied greatly with biopesticide class, nozzle type, and nozzle flow capacity. The DV0.5 of the biopesticides ranged from 75 to 519 µm for 0.76 L min-1 nozzles, from 86 to 509 µm for 1.51 L min-1 nozzles, and from 99 to 622 µm for 2.25 L min-1 nozzles. The use of different biopesticides with the same nozzle significantly altered the spray pattern width. Compared to a water-only solution, the largest change of spray pattern width was 14.7% for the air-induction nozzle (AI11004) discharging FBI-ES. The amount of spray deposited on plant leaves for all tested biopesticides (except HOI) did not vary significantly with different nozzle types. However, the air-induction nozzles produced the most uneven spray deposition patterns. Therefore, to achieve optimal spray application efficiency and effectiveness for discharging specific classes of biopesticide, the choice of the proper nozzle type and flow capacity is critical. Keywords: Biopesticide, Crop protection, Deposition, Droplet size, Spray coverage.

SPRAY DRIFT AND CATERPILLAR AND STINK BUG CONTROL FROM AERIAL APPLICATIONS WITH ELECTROSTATIC CHARGE AND ATOMIZER ON SOYBEAN CROP

ABSTRACT: The use of aerial application with electrostatic charge is an alternative to improve the quality of insecticide applications in soybean crop. The objective of this study was to evaluate the drift and chemical control of the caterpillar and stink bug complex promoted by aerial applications of insecticide in the soybean crop, using electrostatic spray system and rotary atomizers. The insecticide Thiamethoxam + Lambda cyhalothrin was applied with a Cessna 188 Ag Truck agricultural aircraft in two treatments: SPE® electrostatic system, with 54 SPE-5 nozzles and 10 L ha-1 application rate, and Travicar model® 05165 rotary atomizer, with 55° angle blades and application rate of 20 L ha-1. Drift was evaluated through quantification of active ingredient, by means of liquid chromatography, on nylon strings set 20, 40, 80, 160 and 320 m downwind from the applied area. Control efficiency was measured by counting caterpillars and stink bugs found five days after application. The droplet spectrum was also evaluated through water sensitive papers placed in the target area. It was verified that the hydraulic nozzles, associated with the electrostatic system, generated lower drift, but there was no difference in pest control efficiency, in relation to the rotary atomizers.

Dissolved Air Flotation with Saturation of Liquid in Spray-Type Saturator

A new method of dissolved air (pressure) flotation with the spraying of liquid is presented in the paper. The liquid to be treated is sprayed in the saturator with a hydraulic nozzle which makes it possible to increase the contact surface between the liquid and the gas in comparison with the traditional sparged-air saturator system. The proposed method increases the gas content of the liquid entering the flotation unit for treatment. The paper presents the results of experimental research in terms of the efficiency of liquid saturation in a pressure vessel using whirl and spiral nozzles. The volumetric method was used to determine the amount of air released during the dissolved air flotation based on which the sparging rate was calculated. It is shown that, when the liquid is sprayed, the amount of dissolved air increases by an average of 33% compared to a sparged-air pressure vessel. The sparging rate increases with the increase of saturation pressure and essentially depends on the area of the flotation unit. At the saturation pressure above 2 bar, the sparging rate in the center of the flotation unit becomes significantly higher than that in the wall-adjacent area.

Variable air assistance system for orchard sprayers; concept, design and preliminary testing

Conventional air-assisted sprayers with hydraulic nozzles generate large radial spray plumes which produce significant off-target losses and can consume high power (20–30 kW). Also, it is not uncommon to see these machines treating dwarf orchards, where the spray losses at the full leaf stage may be over 80% of applied spray volume. Significant reductions in spray losses can be obtained with targeted and wind-oriented airflow adjustment. The objectives of the presented studies were to develop an energy saving variable air assistance (VAA) system with continuous real-time adjustment of air volume and with spraying systems mounted on both sides of the sprayer. The system is based on a double axial fan system which allows for remote adjustment of air volume. The nominal air output was 20,000 m3 h−1, for use in typical dwarf and semi-dwarf orchards, and this was designed to be obtained with 10 kW power consumption. The system used variable speed impellers with fixed blades which showed greater suitability than a method with adjustable pitch blades working at constant speed because it provided a wider range of air volumes (±35%). The air volumes produced could be continuously adjusted to obtain airflow profiles, on both sides of the sprayer that were almost symmetrical. The results obtained in tests appear to meet the objectives and, therefore, the VAA system can be considered as a suitable prototype platform for variable rate technology and future intelligent orchard sprayers.

Напорная флотация с распыливанием жидкости

This paper presents a new method of dissolved air flotation with spraying of liquid. Liquid that needs cleaning is sprayed inside an overhead reservoir through a hydraulic nozzle allowing to enlarge the contact area between phases in comparison with traditional method of saturation by barbotage. Suggested method makes it possible to increase the gas content of the liquid processed for cleaning into a flotation section. This paper also contains the results of experimental investigation of the effectiveness of liquid saturation inside the overhead reservoir using spray-centrifugal and spray-percussive nozzles. Volumetric method was used to measure the amount of air escaping during dissolved air flotation and the results of the measurement were used to calculate the speed of barbotage. It was identified that when the method of spraying of liquid is applied, the amount of soluble air increases on average by 33% in comparison with overhead reservoir of bubbling type. The speed of barbotage increases with growth of saturation pressure and significantly depends on the area of the flotation section. If the saturation pressure exceeds 2 bars, the speed of barbotage in the center of the flotation cell becomes significantly higher than in the wall area.

DISTRIBUIÇÃO VOLUMÉTRICA E ESPECTRO DE GOTAS DAS PONTAS HIDRÁULICAS LD 11002 E MAG-2

Uma eficiente aplicação de agrotóxico somente é possível ao se dispor de pontas hidráulicas que propiciem distribuição volumétrica satisfatória e espectro de gotas uniforme, uma vez que a ponta é o principal componente da pulverização hidráulica. Desse modo, objetivou-se, com este trabalho, realizar a caracterização técnica das pontas hidráulicas de pulverização LD 11002 e MAG-2. O ensaio da determinação do perfil e da uniformidade de distribuição do jato foi montado em esquema fatorial 2 x 3 x 4, constituído por dois modelos de pontas hidráulicas, três alturas da barra de pulverização e quatro pressões de trabalho, analisados em delineamento inteiramente casualizado, com três repetições para o estudo da uniformidade de distribuição e quinze repetições para o perfil de distribuição. Com os valores do perfil de distribuição foi verificada a simetria de distribuição para a ponta LD 11002. O espectro de gotas foi determinado empregando-se o analisador de partículas a laser modelo Spraytech, e o ensaio foi montado em delineamento inteiramente casualizado, com quatro tratamentos (quatro pressões de trabalho) e com vinte e cinco repetições. As duas pontas não apresentaram distribuição satisfatória à altura de 0,5 m. A ponta LD 11002 apresentou assimetria e esta foi influenciada pela pressão de trabalho. O diâmetro de gotas produzido pelas pontas LD 11002 e MAG-2 reduziu com o aumento da pressão de trabalho.

SPRAY DRIFT AND PEST CONTROL FROM AERIAL APPLICATIONS ON SOYBEANS

Pesticide drift is an issue in modern farming, mainly for crops under constant spraying as soybeans. This study aimed at assessing drift and pest control for aerial application on soybean crops. Hydraulic nozzles and rotary atomizers, regulated to a wide spectrum of droplet sizes, sprayed thiamethoxam and lambda-cyhalothrin using an agricultural aircraft Ipanema 202A at volume rate of 20 L ha-1. Treatments consisted of testing two devices: a rotary cage atomizer (Micronair AU 5000) with blade angles of 65° for larger droplets, and with angle of 55° for smaller ones; and a set of adjustable nozzles (Stol model) with deflector angle of 90° for smaller droplets, and with angle of 30° for larger ones. Drift was evaluated through quantification of active ingredient, by means of liquid chromatography, on nylon strands set 20, 40, 80, 160 and 320 m away from target area, following wind displacement. Control efficiency was measured by counting caterpillars and stinkbugs found five days after spray. Rotary atomizers produced less drift compared to adjustable nozzles at the designed setting. Furthermore, drift can be reduced through a suitable regulation of the devices, keeping an effective pest control.

Review of the published exposure data to pesticides for residents and bystanders, and for environmental risk assessment: Final report

Review of the published exposure data to pesticides for residents and bystanders, and for environmental risk assessment: Final report

АВТОМАТИЗАЦИЯ ПРОЦЕССА МОНИТОРИНГА И РЕГУЛИРОВАНИЯ ДАВЛЕНИЯ В НЕФТЕПРОВОДЕ

It was described the mathematical model of quick and smooth changes and the pressure damping in the pipeline by the method of throttling the flow, implying the use as a regulatory body rotary valves with a variable flow area. The characteristic zones with different flow of the medium in the pipeline were identified: the input and output zone, confusor zone, hydraulic nozzle, the abrupt expansion the channel, the direct channel. The main parameters that characterize a butterfly damper have been brought. The calculation algorithm of pressure losses in the damper was considered, the conclusion about the possibility of its use in creating software to monitor and regulate pressure in the pipeline was made. The place of automatic pressure control system in the system of automation of oil pumping stations was specified, and its functions were allocated. The architecture and structure of database software modeling and control of pressure in the pipeline were described. The tools and technologies used in software development were specified. The description of the algorithm was suggested that regulates the pressure in the pipeline, taking into account the indications that installed on the nodes of the oil pumping stations. The principles of the behavior of the system in case of exceeding the threshold value of the damper in 70 degrees and interaction with the controllers were defined. The user interface of the software and the main scenarios with it were described. The result of the study is to describe the technical and design solutions used in the implementation of software systems for monitoring and controlling the pressure in the pipeline on the basis of a mathematical model. The possibility of using software developed in real time, and for training purposes was mentioned.

900L 냉장고 진공발포시스템 유압노즐의 최적 압력제어에 관한 연구

900L 냉장고 진공발포시스템 유압노즐의 최적 압력제어에 관한 연구

Domestic atmospheric pressure thermal deaerators

Based on many years of experience and proven technical solutions, modern atmospheric pressure deaerators of the capacity of 0.4 to 800 t/h were designed and developed. The construction of such deaerators is based on known and explored technical solutions. A two-stage deaeration scheme is applied where the first stage is a jet dripping level (in a column) and the second one is a bubble level (in a tank). In the design of deaeration columns, low-pressure hydraulic nozzles (Δp < 0.15 MPa) and jet trays are used, and in deaerator tank, a developed “flooded” sparger is applied, which allows to significantly increase the intensity of the heat and mass exchange processes in the apparatus. The use of the two efficient stages in a column and a “flooded” sparger in a tank allows to reliably guarantee the necessary water heating and deaeration. Steam or “superheated” water of the temperature of t ≥ 125°C can be used as the coolant in the deaerators. The commissioning tests of the new deaerator prototypes of the capacity of 800 and 500 t/h in the HPP conditions showed their sustainable, reliable, and efficient work in the designed range of hydraulic and thermal loads. The content of solved oxygen and free carbon dioxide in make-up water after deaerators meets the requirements of State Standard GOST 16860-88, the operating rules and regulations, and the customer’s specifications. Based on these results, the proposals were developed on the structure and the design of deaerators of the productivity of more than 800 t/h for the use in circuits of large heating systems and the preparation of feed water to the TPP at heating and industrial-heating plants. The atmospheric pressure thermal deaerators developed at NPO TsKTI with consideration of the current requirements are recommended for the use in water preparation schemes of various power facilities.

A time-dependent Eulerian model of droplet diffusion in turbulent flow

Industrial sprays are common in many operations where liquid application to surfaces is required. Maximization of the spray process efficacy depends on accurate simulation of spray characteristics and surrounding flow conditions. Traditionally, droplet modeling has been performed using a Lagrangian approach which requires tracking a sufficient number of droplets to form statistical estimates of droplet deposition. Alternatively for this study, an Eulerian-based flow and droplet transport model using the Direct Quadrature Method of Moments (DQMOM) is applied to spray modeling and is coupled with the Reynolds Averaged Navier Stokes (RANS) equations and Shear Stress Transport (SST) turbulence model. A new turbulent diffusion model is developed for droplet transport which accounts for inertia and time-limit effects and covers a wide range of operational parameters associated with aerial spraying. The model is based on a full parametric study using Lagrangian particle tracking in a uniform, homogeneous and isotropic turbulent flow field and is subsequently implemented within the Eulerian DQMOM framework and compared to: 1) Lagrangian tracking predictions of a log-normal particle size distribution injected into a homogeneous, isotropic turbulent flow field, and 2) full-scale experimental wind tunnel measurements in the anisotropic, non-homogeneous wake of a hollow cone hydraulic nozzle.

DROP IMPACT EXPERIMENT AS A MODEL EXPERIMENT TO INVESTIGATE THE ROLE OF OIL-IN-WATER EMULSIONS IN CONTROLLING THE DROP SIZE DISTRIBUTION OF AN AGRICULTURAL SPRAY

Agricultural spraying involves atomizing a liquid stream through a hydraulic nozzle, thus forming a liquid sheet that is subsequently destabilized into drops. Standard adjuvants such as dilute oil-in-water emulsions are known to influence the spray drop size distribution. Although being documented, the physical mechanisms at the origin of the size increase remain unclear. To elucidate the mechanisms causing the changes on the drop size distribution, we investigate the influence of dilute emulsions on the destabilization mechanisms of liquid sheets. Model laboratory experiments based on the collision of a liquid tear on a small solid target are used to produce and characterize liquid sheets. With dilute oil-in-water emulsions, the liquid sheet is destabilized during its expansion by the nucleation of holes that perforate the sheet and grow. The emulsion concentration and the size of the oil droplet of the emulsion are varied to rationalize their influence on the sheet destabilization mechanisms. The results obtained with the model laboratory experiments are compared to the measurement of the drop size distribution resulting from a conventional agricultural spray. The very good correlation between the number of perforation events and the volume fraction of small drops in the spray suggests (i) that the model experiment on liquid sheet is appropriate to investigate and gain an understanding of the physical mechanisms governing the spray drop size distribution and (ii) that the perforation destabilization mechanism of liquid sheets, which dominates for dilute emulsions, is at the origin of the increase of the size of the spray drops.

Effectiveness of a Low-volume Spray Technology in the Control of Major Strawberry Diseases in Florida

Florida strawberry production is greatly affected by Botrytis and anthracnose fruit rots (BFR and AFR), caused by Botrytis cinerea and Colletotrichum acutatum, respectively. Fungicide applications are the most effective method for control of both diseases. Traditionally, Florida strawberry growers use sprayers mounted with hydraulic nozzles delivering high flow rates. The objective of this study was to compare the standard hydraulic nozzle (SHN) sprayer with the air-assisted rotary atomizer (AARA). The effects of low volumes on the control of BFR and AFR, the reduction of 25% on fungicide rate, and their operational efficiency were evaluated, and an economic analysis was conducted. Two experiments were conducted (in the 2014-2015 and 2015-2016 seasons) where three treatments were compared: two using the AARA at 25 gal/acre, one of these with 75% of the fungicide rate; and one using the SHN at 100 gal/acre. In the first season, yield, AFR control, and BFR control were similar for all three treatments. In the second, BFR control was similar among all the treatments. However, the AARA treatment had a higher yield than the SHN, with the AARA (75% rate) being more productive. The operational capacity in acres per hour of the AARA was 17% higher than the SHN. Labor and fungicide costs were lower in the AARA treatments. Thus, the technology was shown to be a good fit for Florida growers.Accepted for publication 25 October 2016.

Development and Preliminary Evaluation of a Spray Deposition Sensing System for Improving Pesticide Application.

An electronic, resistance-based sensor array and data acquisition system was developed to measure spray deposition from hydraulic nozzles. The sensor surface consisted of several parallel tin plated copper traces of varying widths with varying gap widths. The system contained an embedded microprocessor to monitor output voltage corresponding to spray deposition every second. In addition, a wireless module was used to transmit the voltage values to a remote laptop. Tests were conducted in two stages to evaluate the performance of the sensor array in an attempt to quantify the spray deposition. Initial tests utilized manual droplet placement on the sensor surface to determine the effects of temperature and droplet size on voltage output. Secondary testing utilized a spray chamber to pass nozzles at different speeds above the sensor surface to determine if output varied based on different application rates or spray droplet classification. Results from this preliminary analysis indicated that manual droplets of 5 and 10 μL resulted in significantly different values from the sensors while temperature did not consistently affect output. Spray chamber test results indicated that different application rates and droplet sizes could be determined using the sensor array.

Pontas hidráulicas, adjuvante e horários de aplicação de fomesafen no controle de picão-preto

A aplicação de defensivos agrícolas é afetada por diversos fatores, dentre eles, destaca-se o momento da aplicação, que pode variar de acordo com o alvo, o produto aplicado e equipamento utilizado. Objetivou-se avaliar pontas hidráulicas, adjuvante e horários de aplicação de fomesafen no controle de picão-preto. Os tratamentos foram arranjados em esquema fatorial 4x2x2, com o primeiro fator constituído de quatro pontas (API-11002; jato leque simples-JLS, AD/D-11002; jato leque duplo-JLD, AVI TWIN-11002; jato leque duplo com indução de ar-JLDIA, e APM-09502; jato leque simples de impacto-JLSIP). O segundo de dois horários de aplicação (3 e 16 horas) e o terceiro de duas misturas em tanque (com e sem adição de adjuvante espalhante adesivo não iônico). Os tratamentos foram avaliados sete, 14 e 21 dias após à aplicação, através do número de plantas vivas, altura das plantas, análise visual e aos 21 dias foi feita matéria seca da parte aérea. A aplicação às 16 horas proporcionou maior controle de todas as características avaliadas, a ponta JLSIP se destacou causando maior redução de matéria seca e de plantas vivas e a adição de adjuvante potencializou o controle da aplicação às 16 horas. O horário de aplicação influencia a ação do herbicida fomesafen, sendo que, sua aplicação às 16 horas proporciona maior controle de B. pilosa em relação à realizada às 3 horas. A ponta JLSIP aumenta a ação de fomesafen e a adição de adjuvante potencializa o efeito desta ponta e da aplicação realizada às 16 horas.

Some Aspects of Designing and Developing Higher Performing Hydraulic Nozzles for Ground Crop Sprayers in the UK

Some Aspects of Designing and Developing Higher Performing Hydraulic Nozzles for Ground Crop Sprayers in the UK

Effect of adjuvant types and concentration on spray drift potential of different nozzles

Pesticide exposure via spray drift can have a negative impact on bystanders, residents, livestock, terrestrial and aquatic ecosystems. Reducing pesticide spray drift and maximizing efficacy are the paramount considerations when selecting technologies and operating parameters prior to making an application. With the increasing awareness about the potential risk of pesticides, many mitigation measures for pesticide exposure via spray drift have been developed. The effect of spray adjuvant and pesticide formulations is not yet well evaluated and implemented into drift mitigation scenarios. It is often stated that drift reduction with an appropriate nozzle is greater than those achieved by formulated products or spray adjuvant. In fact, to explore the combined effect of nozzle type and physical properties of spray liquids is also important. In order to study effect of adjuvant on spray drift potential of different nozzles, we used wind tunnel, and spectrofluorophotometor to carry out experiment which focused on how concentration of anti-evaporation adjuvant Agrospred 730AS-2, anti-drift adjuvant Break-thru Vibrant, Silwet DRS-60 and Greenwet 360 were affected by Drift Potential Index (DIX) of conventional flat fan nozzle Lechler ST 110-015, hollow cone nozzle TR 80-015, reference nozzle Lumark F110-03 and rotary nozzle. It has been reported in literature that the amount of spray drift is usually related to the percentage of fine spray droplets. The smaller a spray droplet, the longer it remains as airborne and the higher the possibility for it to be carried away by crosswind. Moreover, spray droplets of a few microns in size can evaporate before sedimentation. Therefore, it is fundamentally important to measure droplet size and the size distribution to understand the environmental and the biological fate of spray droplets. In this article, Malvern particle sizer was used to test Volume Median Diameter (VMD) and the percentage of droplets with diameter 75 μm of the four nozzles above. The concentration of AS-2 solution was 0, 0.005 %, 0.05 %, 0.5 %, the concentration of Break—thru Vibrant solution was 0, 0.1%, 0.2%, 0.4 %, the concentration of Silwet DRS-60 solution was 0, 0.1%, 0.2%, 0.4%,0.8% and the concentration of Greenwet 360 solution was 0, 0.3% respectively. In the test, Pyranine 120% (0.01%) tracers were used to test and analyze the spray drift potential. The results showed that: when spraying 0.05% solution with anti-evaporation adjuvant AS-2, DIX of rotary nozzle (6 000 r/s, 400 mL/min) increased 81.8%, VMD increased 16.7% compared with water under the condition of which wind speed was 1.8 m/s, temperature was 30oC, humility was 40% in the wind tunnel. With the concentration of 0.8%, 0.4% and 0.3%, respectively, anti-drift adjuvant Silwet DRS-60, Break-thru Vibrant and Greenwet 360 can significantly reduce the spray drift. Especially for TR 80-015, DIX decreased 98.7%, 58.2% and 80.1% separately with the adjuvant above compared with water. The drift reduction performance of three hydraulic nozzles was TR80-015>ST110-015>Lumark F110-03 under the condition of which wind speed was 2 m/s, temperature was 20, humility was 80 % in the wind tunnel. For rotary nozzle, DIX decreased 70.3 % and 26.0 % with 0.8% Silwet and 0.3 % Greenwet 360 separately, while Break—thru Vibrant had no effect on it. For Silwet DRS-60 and Greenwet 360, DIX increased as the volume percentage of droplets with diameter 75 μm increased which showed positive correlation (the correlation coefficient R>0.5);DIX decreased as VMD increased which showed negative correlation, so VMD and volume percentage of droplets with diameter 75 μm were considered to be important factors affecting drift potential.