The effect of air velocity and proximity on the charging of sprays from conventional hydraulic nozzles

Gan–Mor, S.; Ronen, B.; Ohaliav, K.

doi:10.1016/j.biosystemseng.2014.03.004

Cited by 15 publications

(10 citation statements)

References 20 publications

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“…Charging Slope (mC kg -1 kV -1 ) Model (eq. 10) (mC kg -1 kV -1 ) Moon et al (2003) 2.10 3.0 65 0.75 0.70 0.28 Jia et al (2015) 1.00 4.0 84 0.33 0.25 0.29 Marchant and Green (1982) 1.31 6.0 155 0.17 0.22 0.16 Gan-Mor et al (2014) 1.85 10.5 115 0.45 0.18 0.16 Ru et al (2011) 2.35 20.0 81 0.67 0.12 0.22 Laryea and No (2003) 0.37 5.0 113 0.69 0.07 0.12…”

Section: Resultsmentioning

confidence: 99%

A Review of the Effects of Droplet Size and Flow Rate on the Chargeability of Spray Droplets in Electrostatic Agricultural Sprays

Post¹,

Roten²

2018

Transactions of the ASABE

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Abstract. The chargeability of liquid sprays is an important factor in determining the deposition efficiency of electrostatic pesticide sprays. The Rayleigh limit provides information on the maximum amount of charge a spray droplet can carry as a function of droplet size and liquid properties. This article reviews the literature to determine what fraction of the Rayleigh limit is achievable. Typically, less than 10% of the Rayleigh limit charge is obtained. The droplet charge per unit mass decreases with increasing droplet size and liquid flow rate. A correlation equation is derived from published data to predict spray droplet charge per unit mass from droplet size, flow rate, and charging voltage. Keywords: Droplet size, Electrostatic charging, Spray drift, Sprayers, Ultra-low volume spraying.

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Section: Resultsmentioning

confidence: 99%

A Review of the Effects of Droplet Size and Flow Rate on the Chargeability of Spray Droplets in Electrostatic Agricultural Sprays

Post¹,

Roten²

2018

Transactions of the ASABE

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“…The charged spray droplets created wraparound effect [69,79] to exterminate hidden insect pests [80] . Spray deposition at the underside of citrus leaves to control whitefly also improved bio-efficacy from airblast electrostatic sprayers [73] , while that of grape leaves was 200% effective [70] . The positive results were achieved due to oppositely charged polarity between the charged droplets and the substrates ions.…”

Section: Electrostatic Droplet Impact Behavior On the Substratesmentioning

confidence: 98%

“…For an electrostatic application of glyphosate, higher VDM of 112.8 µm was measured at 10.0 kV applied voltage [50] . Also, volume median diameter of 115 μm and 1.85 mC/kg charge-mass ratio were obtained in an experiment to inject charges to spray droplets from hydraulic nozzles at 400 kPa spray pressure and 0.45 L/min liquid flow rate [70] . The above droplet sizes are suitable for effective deposition and interactive effect in electrostatic spraying system.…”

Section: Electrostatic Droplets Characteristics From Pesticides Spraymentioning

confidence: 99%

Review of electrostatic system parameters, charged droplets characteristics and substrate impact behavior from pesticides spraying

Appah

Wang

et al. 2019

International Journal of Agricultural and Biological Engineering

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Electrostatic spraying application is adopted in crop protection to prevent pest infestation, to improve product quality and to maximize yield. It involves a superposition of charges to pesticide spray droplets to attract substrate ions at obscured surfaces. The droplets wraparound effect reduces off-target deposition, enhances on-target spray and invariably improves spray efficiency. Electrostatic spraying system works effectively at optimum parameters in combination with charging voltages, application pressures, spraying height regimes, flow rate, travel speed, electrode material, and nozzle orientation. Many combinations of the system parameter settings have been systematically used by researchers for the electrostatic application, but there are unknown specific optimum parameters combinations for pesticide spraying. Since droplets chargeability influences the effectiveness of electrostatic spraying system, the parameters that produce ideal charge to mass ratio determine the functionality of the spraying deposition, retention and surface coverage. This article, therefore, analyses electrostatic system parameters that produce suitably charged droplets characteristics for effective impacting behavior of pesticides on substrates. Increasing applied voltages consequently maximizes charge-mass ratio to optimum and starts declining upon further increase in voltages beyond a critical point. This review further proposes the selection of an optimum electrostatic parameters combination that yields optimum droplets chargeability in pesticide application. Also, it is necessary to investigate the charge property of substrates prior to pesticide application in order to superpose the right opposite charge on spray droplets at rupture time during electrostatic spraying system.

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“…These results indicate that using a population of small (40 µm, according to the manufacturer), electrostatically charged droplets allows the underside of the leaves to be reached more efficiently than the spraying systems without charge. Maski and Durairaj [37] and Gan-Mor et al [38] obtained similar results when comparing an electrostatic system with and without charge. Specifically, Gan-Mor et al [38] recorded a deposition two-times higher on the underside of the grapevine when using an electrostatic system compared to using one without charge.…”

Section: Plant Canopy Depositionmentioning

confidence: 60%

Evaluation of Electrostatic Spraying Equipment in a Greenhouse Pepper Crop

et al. 2022

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Greenhouse vegetable production is of great importance in southern Europe. It is a cultivation system characterised by a high planting density and environmental conditions that favour the development of pests and diseases. Although alternatives to chemical pest and disease control have been used over recent years in greenhouse crops, it is still mostly plant protection products that are used to protect crops and prevent crop losses. Hand-held spraying equipment is mainly used to apply plant protection products to this type of crop. This equipment is technologically basic, offering low deposition efficiency in the plant canopy, high losses to the ground, and a high risk of worker exposure. In this context, it is important to utilise technologies that reduce the problems associated with using the conventional hand-held sprayers in greenhouses. This study evaluated the deposition and uniformity in the plant canopy and the losses to the ground when applying plant protection products with an electrostatic hand-held sprayer; the results were then compared with applications carried out using a conventional hand-held sprayer. For this purpose, a colorimetric method has been used based on the application of a tartrazine solution. The tests showed that the electrostatic spraying equipment increased the plant canopy deposition by 1.48 times that of the hand-held spray gun, resulting in a 48% reduction in the application rate. There was also a 1.78-times increase in deposition on the underside of the leaves and a 36.36% reduction in losses to the ground. In general, the electrostatic hand-held sprayer improves the effectiveness of the plant canopy deposition and reduces losses to the ground compared to the hand-held spray gun commonly used in pest and disease control.

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The effect of air velocity and proximity on the charging of sprays from conventional hydraulic nozzles

Cited by 15 publications

References 20 publications

A Review of the Effects of Droplet Size and Flow Rate on the Chargeability of Spray Droplets in Electrostatic Agricultural Sprays

A Review of the Effects of Droplet Size and Flow Rate on the Chargeability of Spray Droplets in Electrostatic Agricultural Sprays

Review of electrostatic system parameters, charged droplets characteristics and substrate impact behavior from pesticides spraying

Evaluation of Electrostatic Spraying Equipment in a Greenhouse Pepper Crop

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