Flat-fan Spray Nozzles Research Articles

Droplet size from Venturi air induction spray nozzles

Sprays are of great importance for many applications, with drop size being a crucial parameter. Especially in agriculture applications, simple flat fan spray nozzles are often supplemented by a Venturi component to achieve larger drop sizes and hence, prevent unwanted spray drift of the smallest droplets. The general believe is that these larger drops are usually attributed to the fact that the liquid sheet produced by the nozzle breaks up more easily due to the pre-existing ’holes’ formed by the induced air bubbles. Here, we extend descriptions of how nozzle and fluid parameters determine droplet size distributions from Venturi nozzles. We show that the mean droplet size is determined by the nozzle’s orifice area as is the case for ordinary flat fan nozzles, but that the additional pressure drop over the Venturi chamber needs to be taken into account. Using this parameter, relations that were derived for flat fan nozzles can be re-used. This allows to show that the increase in droplet size compared to conventional nozzles is due to the additional pressure drop in the Venturi chamber, and not to a change in breakup mechanism due to the presence of air bubbles in the liquid sheet.

​Weed Control using Pre-emergence Herbicide Strip Application System Along with Sowing/Planting Devices

A 6-row pre-emergence herbicide strip-application system was designed and developed at ICAR-CIAE, Bhopal as an attachment to inclined-plate planter to apply herbicide at the time of sowing in widely spaced crops to control weeds along the crop rows, often not possible in mechanical weeding. It consisted of a frame on which 6 flat fan spray nozzles were mounted by means of clamps, a single action piston pump with 9 l/min capacity, pressure regulator valve and pressure gauge and pressure pipes. The spacing between the spray nozzles, angle and height of spray nozzles can be varied by adjusting the clamps. The developed system has ability of strip as well as blanket application of herbicide. The same machine can be used as post-emergence herbicide/pesticide applicator after the removal of furrow openers and increasing the height of nozzles from the ground. The machine was tested and evaluated during Kharif season for soybean and pigeon pea crops. The field capacity of the developed system was found to be 0.4 ha/h. The operating cost of the pre-emergence herbicide applicator with inclined plate planter was worked out as Rs 1350/- per ha. It can save about 40-50% herbicide.

Visualisation of the evolution of perforations in oil-based emulsion sheets formed by flat-fan spray nozzles

Oil-based emulsions are been widely used to apply agricultural sprays and they are often delivered through flat-fan spray nozzles mounted on booms. Perforations are one of the typical structures of found during the atomisation of oil-based emulsions, and they are investigated here using visualisation. The generation, development and coalescence of perforations in an expanding liquid sheet are comprehensively studied. The results support the existence of two perforation-generation mechanisms, namely puncture and tear mechanisms. The tear mechanism depends on the thickness modulation of spray sheet caused by surface disturbances. The perforations that are produced by the tear mechanism are widely distributed and are large in number compared with those associated with the puncture mechanism. The increase of the area of perforation exhibits firstly an acceleration followed by a deceleration. The former is ascribed to the effects of surface tension and the expansion of the spray sheet in a spanwise direction, whilst the latter is related to the interaction between perforations. After perforations are formed, the evolution of the area of the perforation is insensitive to the generation mechanism. Generally, the coalescence of two perforations gives rise to one ligament; however, it is demonstrated that multiple ligaments can be produced if the momentums of the perforations are great enough.

Phytotoxicity in soybean crop caused by simulated dicamba drift

Abstract: The objective of this work was to evaluate injury symptoms on soybean not tolerant to dicamba (3,6-dichloro-2-methoxybenzoic acid), as well as crop yield, after the application of sub-rates of the herbicide to simulate physical drift in tropical conditions. Dicamba rates of 0, 5.8, 14.4, 28.8, 57.6, and 576 g acid equivalent per hectare were applied at the vegetative (V3) and reproductive (R1) stages of soybean, using a backpack sprayer pressurized with CO2, equipped with air-induction flat fan spray nozzles; the pressure and rate of application were 250 kPa and 200 L ha-1, respectively. Visible injury, the soil-plant analysis development (SPAD) index (leaf chlorophyll content) at 14 days after herbicide application, and soybean crop yield were evaluated. These variables were influenced by the crop stage in which the dicamba rates were applied. Rates below 28.8 g ha-1 caused less injury to soybean when applied at the R1 stage; however, there were no differences in yield between stages. A 1% dicamba drift in tropical conditions reduces soybean yield by 12%.

Effect of angled spray nozzle designs on spray distribution and droplet spectrum

ABSTRACT New technologies have been developed to promote uniform, sustainable, safe and effective application of phytosanitary products. In this scenario, spray nozzles of different designs and jet angles can optimize application. Therefore, we aimed to analyze the effect of angled flat fan spray nozzles on spray pattern uniformity and droplet spectrum formation. The spray volumetric distribution of standard flat fan, double flat fan and the new angled flat fan spray nozzle, using two spray volumes were assessed. For that, the spray pattern distribution and the coefficient of variation (CV) were determined. The droplet spectrum characterization produced by the same treatments was performed in a real-time particle size analyzer. Also the effect of adding a fungicide mixture associated with an adjuvant on droplet formation was evaluated. All spray nozzles, regardless of design and spray volumes evaluated, produced CV values below 7%, considered acceptable by international uniformity standards. There was a difference in spray pattern according to the spray nozzle design and spray volume. It was evidenced that the main differences found in droplet spectrum occurred due to spray nozzle type, spray mixture and nominal flow rate, with little influence of spray jet angled or spray volumes.

Modeling and Prediction of the Uniformity of Spray Liquid Coverage from Flat Fan Spray Nozzles

The effectiveness and quality of agricultural spraying largely depends on the technical efficiency of the nozzles installed in agricultural sprayers. The uniform spraying of plants results in a decrease in the amount of pesticides used in agricultural production and affects environmental safety. Both newly developed sprayers and those currently in use need quality control as well as an assessment of the performance of the spraying process, especially its uniformity. However, the models applied presently do not ensure accurate estimates or predictions of the spray liquid coverage uniformity of the treated surface. Generally, the distribution of the atomized liquid quantity is symmetrical and leptokurtic, which means that it does not fit well to the commonly used standard distribution. Therefore, there is a need to develop and design new tools for the evaluation, modeling, and prediction of such a process. The research problem studied in the present work was to find a new model for the distribution of atomized liquid quantity that could provide capabilities better than have been available so far to assess and predict the spraying process results. The research problem was solved through the formulation of a new function for the probability density distribution of sprayed liquid accumulation on the surface of the preset dimension size. The development of the new model was based on the results from a series of water atomization tests with an appropriate measurement device design based on the widely applied flat fan nozzles (AZ-MM type).

Influence of working pressure and spray nozzle on the distribution of spray liquid in manual backpack sprayers

ABSTRACT Manual backpack sprayers are widely used in rural properties in Brazil. However, studies that assess their working characteristics, especially spray tip models and working pressure conditions, are scarce. Thus, the aim of this study was to assess how much the working pressure and spray tips influence the distribution quality of phytosanitary spray solutions in manual backpack sprayers. Four spray nozzles (standard flat-fan Magnojet TP11002, turbo flat-fan TeeJet TT11002, hollow-cone TeeJet TXA8002, and disc-core) were assessed in a patternator table at 1, 2, 3, and 4 bar. Analyses of spray distribution profile were performed by symmetry and the coefficient of variation (CV) analysed by the Tukey’s test (p < 0.05). Spray tip models and working pressure influenced in more than 100% the distribution uniformity values of spray solution and in about 50% the useful range of the phytosanitary treatment. Among the models assessed in this study, the turbo flat-fan spray nozzle presents the best set of characteristics to be indicated for manual backpack sprayers aiming at field phytosanitary treatments.

Effect of Formulations and Spray Nozzles on 2,4-D Spray Drift under Field Conditions

Six trials were conducted during 2014/15 and 2015/16 growing seasons in Brazil to determine the effect of 2,4-D formulations and spray nozzles on 2,4-D spray drift under conventional field conditions. An experimental 2,4-D choline formulation with Colex-D® Technology (GF-3073) and a 2,4-D dimethylamine (DMA) formulation were applied with either XR and AIXR flat-fan spray nozzles. Each plot was 30 m wide by 24 m long (720 m2) with 60 glyphosate-resistant soybean rows spaced 50 cm apart and also 35 potted tomato plants distributed on a grid across the plot 5-m apart. Applications were performed one meter away from the plot edge perpendicular to the soybean rows when wind direction was parallel to the rows with less than 30 degrees of angle deviation. Spray drift treatments were applied in 100 L ha−1 with tractor sprayers at 276 kPa equipped with a 7-m wide boom at 50 cm above the canopy of the soybean plant, operating at 6.8 km h−1. The distance from the plot edge to the farthest plant with 2,4-D symptoms was assessed for every four soybean rows at 10 and 20 days after treatment (DAT) and potted tomatoes at 10 DAT. GF-3073 reduced the distance of the farthest injured plant with 2,4-D symptoms compared to the 2,4-D DMA formulation regardless of the spray nozzle, assessment date and sensitive species. GF-3073 applied through the AIXR nozzle reduced the relative drift affected area to the standard by 68% at 10 DAT and 67% at 20 DAT for soybean and 60% at 10 DAT for potted tomatoes.

Flat-Fan Spray Atomization Model

Abstract. In pesticide application, the lack of a suitable theoretical atomization model for flat-fan spray nozzles forces a reliance on empirical data and correlations, even for computational simulations. There is considerable difficulty in the theoretical analysis of the liquid sheet emanating from flat-fan nozzles because no simplification to a two-dimensional analysis can be employed, as is done for cylindrical jets. Nonetheless, 50 years ago, Dombrowski and co-workers used linear stability analysis to analyze the breakup of flat-fan spray sheets into ligaments and from ligaments to droplets. Their correlations have not found use because they include parameters that are difficult, if not impossible, to measure. In this work, the Dombrowski model is simplified using dimensional analysis, resulting in a correlation to predict the volume median diameter of flat-fan sprays in terms of common user parameters, i.e., the nozzle size and operating pressure. Keywords: Atomization, Droplet size, Nozzles, Pesticides, Sprayers.

Predicting the dynamic impact behaviour of spray droplets on flat plant surfaces.

The dynamic impact behaviour of water droplets on plant surfaces was investigated based on a multiphase computational fluid dynamics (CFD) model. The study was conducted using the Volume Of Fluid (VOF) approach. The static contact angle of water droplets on leaf surfaces of different plants (apple, pear, leek and cabbage) was measured and found to vary between 54.9 and 138.2°. Impact experiments were conducted by monitoring the flow and impact characteristics of water droplets on leaves in still air with a high speed camera. Droplets were generated by an agricultural flat fan spray nozzle moving across the leaf at constant speed. The nozzle produced droplets with diameters ranging from 20.6 up to 550.8 μm, and droplet velocity values near the impact between 0.03 and 13.2 m s(-1). The CFD model was capable of predicting the observed dynamic impact behaviour of droplets on the plant surfaces. The fate of the droplets after the impact process for adhesion, bouncing or splashing was accurately predicted for Weber numbers (We) in the range of 0.007 to 1096 and droplet Reynolds numbers (Re) between 5 to 8000. The process was highly dependent on the surface and droplet flow characteristics during the impact. Combinations of We, Re and Ohnesorge (Oh) numbers defined the droplet maximum spread factor, the number of secondary droplets generated as a result of the splashing process and the transition between the different impact outcomes. These criteria can then be used in field scale spray deposition and drift models to better understand agricultural spray operations.

Efeito da pressão de trabalho e de modelos de pontas de pulverização sobre a eficiência de herbicida de contato em soja

Nos últimos anos, nas aplicações de herbicidas de contato em pós-emergência, tem-se verificado tendência de redução do volume de calda e a utilização de pontas de pulverização que operam com baixas pressões. Com o objetivo de avaliar pontas de pulverização de jatos planos, das séries Teejet XR, DG, TT e AI, operadas com três níveis de pressão de trabalho, foi conduzido um experimento visando ao controle de picão-preto (Bidens spp.), aplicando-se em pós-emergência da cultura da soja o herbicida de contato bentazon. As pontas de jatos planos das séries Teejet XR 110015, DG 110015 e TT 110015 foram operadas com pressões de 100; 200 e 300 kPa, e a ponta AI 110015, nas pressões de 200; 300 e 400 kPa. Avaliaram-se os níveis de controle das plantas de picão-preto aos 7; 14 e 21 dias após a aplicação dos tratamentos e a produtividade de grãos da cultura da soja. Observaram-se diferenças entre as pontas de pulverização e entre as pressões utilizadas. A ponta AI 110015 mostrou-se ineficiente para esse uso em todas as pressões avaliadas. A pressão de 100 kPa mostrou-se inadequada para aplicações em pós-emergência de herbicida com ação de contato com as pontas XR, DG e TT. O aumento da pressão de pulverização reflete melhor controle das plantas daninhas com o herbicida utilizado.

Evaluation of Karate for Rice Water Weevil (RWW) Control, 1995

Abstract Karate was evaluated for control of rice water weevil at the Rice Research Station, Crowley, LA. Collectively levied plots, 5 X 20 ft, were arranged in a RBD with 4 blocks and 8 treatments with sub-sample nesting within the block X treatment effect. Fertilizer was incorporated pre-plant and applied broadcast 3 wk post-flood at 90 lb (13-13-13) and 50 lb (21-0-0) N-P-K/acre, respectively. Plots were water seeded 29 May with pre-soaked ‘Cyprus’ rice at 138 lb seed/acre to Crowley silt loam and permanently flooded 8 Jun. Foliar applications of Karate were applied at 0.3 lb (AI)/acre. Furadan 3 G was applied at RWW threshold (5 larvae/sample) at 0.6 lb (AI)/acre using a hand-held shaker. Karate applications were made using a CO2 backpack sprayer delivering 15 gpa at 16 psi with 80015VS flat-fan spray nozzles on a 3 ft boom. RWW eggs were counted from 5 randomly selected plants per plot beginning 2 d post-flood then weekly until RWW threshold. Three randomly selected soil samples per plot were taken 26 Jun, and 3 and 11 Jul using a 4 X 4 in core sampler. Individual samples were washed through a funnel, fitted with wire screen, into a 35-mesh screen sieve. Collected rice water weevil larvae and pupae were floated in a saturated NaCl solution, and counted. Rough rice yield (lb/acre) was determined by hand-harvesting one random 3-ft2 sample per plot on 19 Sep. Moisture content of harvested grain was determined and standardized to 12% for determination of rough rice yield. All data were subjected to ANOVA. Experimental and sampling error terms for the RWW larval data were tested for homogeneity of variances, and pooled error terms were used to test the treatment effect when appropriate. Protected least significant differences (LSD) was used for treatment mean separation.

Evaluation of Dimilin for Rice Water Weevil Control, 1995

Abstract Dimilin was evaluated for control of adult rice water weevil at the Rice Research Station, Crowley, LA. Collectively levied plots, 5 X 20 ft, were arranged in a RBD with 4 blocks and 5 treatments with sub-sample nesting within the block X treatment effect. Fertilizer was incorporated pre-plant and applied broadcast 3 wk post-flood at 90 lb (13-13-13) and 50 lb (21-0-0) N-P-K/acre respectively. Plots were water seeded 29 May with pre-soaked ‘Cyprus’ rice at 138 lb seed/acre to Crowley silt loam and permanently flooded 8 Jun. Foliar applications of Dimilin 25 W were made at 0.25 or 0.125 lb (AI)/acre. Furadan 3 G was applied at RWW threshold (5 larvae/sample) at 0.6 lb (AI)/acre using a hand-held shaker. Dimilin 25 W applications were made using a CO2 backpack sprayer delivering 15 gpa at 16 psi with 80015VS flat-fan spray nozzles on a 3 ft boom. Rice water weevil eggs were counted from 5 randomly selected plants per plot beginning 2 d after flood then weekly until RWW threshold. Three randomly selected soil samples per plot were taken 26 Jun, 3 and 11 Jul using a 4 X 4 in core sampler. Individual samples were washed through a funnel, fitted with wire screen, into a 35-mesh screen sieve. Collected RWW larvae and pupae were floated in a saturated NaCl solution, and counted. Rough rice yield (lb/acre) was determined by hand-harvesting one random 3-ft2 sample per plot on 19 Sep. Moisture content of harvested grain was determined and standardized to 12% for determination of rough rice yield. RWW larval data were log transformed to improve normality. All data were subjected to ANOVA. Experimental and sampling error terms for the RWW larval data were tested for homogeneity of variances, and pooled error terms were used to test the treatment effect when appropriate. Protected least significant difference (LSD) was used for treatment mean separation.

Flame Cultivation as a Complement to Mechanical and Herbicidal Control of Weeds

ABSTRACT There is renewed interest in the practice of flame cultivation as a complement to mechanical cultivation and a partial or total replacement for herbicides in vegetable crops. This interest is fueled by three factors: (1) an increasingly negative public perception of herbicide use in vegetables, (2) a limited selection of herbicides labelled for vegetables, and (3) limited efficacy of some of the registered herbicides. Flame cultivation, in combination with mechanical cultivation, can replace or complement herbicides in some vegetable crops. Flame cultivation bursts plant cell walls as the weeds are heated. Most vegetable crops must be protected from the flame. This can be done with a height differential between weeds and crop, a water shield (water sprayed from a flat fan spray nozzle), or a physical shield. A field study involving flame cultivation of lima beans (Phaseolus limensis Macfady) and southern peas (Vigna unguiculata [L.] Walp.) has shown that multiple flame cultivations are effective ...

Evaluation of Karate For Rice Water Weevil Control, 1996

Abstract Karate was evaluated for RWW control at the Rice Research Station, Crowley, LA. Plots, 5 X 20 ft, were arranged in a RB design with four blocks and seven treatments with sub-sample nesting within the block X treatment effect. Fertilizer was incorporated pre-plant and applied broadcast 3 wk post-flood at 90 lb (13-13-13) and 55 lb (21-0-0) N-P-K/acre respectively. Plots were water-seeded 21 May with pre-soaked ‘Cyprus’ rice at 130 lb seed/acre to Crowley silt loam and permanently flooded 28 May. Furadan 3G was applied 18 Jun at 0.6 lb(AI)/acre using a hand-held shaker. Karate applications were made using a CO2 backpack sprayer delivering 15 gpa at 28 psi with 10015VS flat-fan spray nozzles on a 3 ft boom. Three randomly selected soil samples per plot were taken 10, 17, 25 Jun using a 4 X 4 in core sampler. Individual samples were washed through a funnel, fitted with wire screen, into a 35 mesh screen sieve. Collected RWW larvae and pupae were floated in a saturated NaCl solution, and counted. Rough rice yield (lb/acre) was determined by harvesting the center 4 rows per plot using a Kubota combine 11 Sep. Moisture content of harvested grain was determined and standardized to 12% for determination of rough rice yield. All data were subjected to ANOVA. Experimental and sampling error terms for the RWW larval data were tested for homogeneity of variances, and pooled error terms were used to test the treatment effect when appropriate. Protected Least Significant Difference (LSD) was used for treatment mean separation at 0.05 probability level.

PRECISION BAND SPRAYING WITH MACHINE-VISION GUIDANCE AND ADJUSTABLE YAW NOZZLES

A system was developed for precision, ground-based application of foliar sprays to rows of small plants. Thesystem consisted of a machine-vision guidance system that positioned spray nozzles directly above each row of smallplants. An electrically actuated mechanical linkage rotated flat-fan spray nozzles about their central axes to vary the yawangle of the fans relative to the direction of travel. The nozzle rotation effectively changed the width of the spray patternrelative to the direction of travel and allowed the spray band to be adjusted to match the width of the target plants. Thesystem was evaluated on young stands of tomatoes and lettuce by measuring spray deposition on the plants andsurrounding soil. The precision system allowed spray application rates to be reduced by 66 to 80% and increased spraydeposition efficiency on the target plants by 2.5 to 3.7 times greater than conventional broadcast spraying. Nontargetdeposition on soil surfaces was reduced by 72% to 90%. Airborne displacement of spray liquid from the spray boom, asmeasured by collection strings surrounding the boom structure, was reduced by 62 to 93%. The reduction in displacementsuggested that spray drift from precision applications could be significantly less than that from conventional applications.

Evaluation of Guardian For Rice Water Weevil Control, 1995

Abstract Guardian was evaluated for RWW Control at the Rice Research Station, Crowley, LA. Collectively levied 5 X 20 ft plots were arranged in a RB design with 4 blocks and 4 treatments with sub-sample nesting within the block X treatment effect. Fertilizer was incorporated pre-plant and applied broadcast 3 wk post-flood at 90 lb (13-13-13) and 50 lb (21-0-0) N-P-K/acre respectively. Plots were water-seeded 29 May with pre-soaked ‘Cyrpus’ rice at 138 lb seed/acre to Crowley silt loam and permanently flooded 8 Jun. Foliar applications of Guardian were applied at 14.5 oz formulation/acre. Furadan 3G was applied at 0.6 lb (Al)/acre using a hand-held shaker when RWW larval density was at or above threshold (5 larvae/sample). Guardian applications were made using a CO2 backpack sprayer delivering 15 gpa at 16 psi with 80015VS flat-fan spray nozzles on a 3 ft boom. RWW eggs were counted from 5 randomly selected plants per plot beginning 2 days post-flood, then weekly until RWW threshold. Three randomly selected soil samples per plot were taken 26 Jun, and 3 and 11 Jul using a 4 X 4 in core sampler. Individual samples were washed through a funnel, fitted with wire screen, into a 35 mesh screen sieve. Collected RWW larvae and pupae were floated in a saturated NaCl solution, and counted. Rough rice yield (lb/acre) was determined by hand-harvesting one random 3 ft2 sample per plot on 19 Sep. Moisture content of harvested grain was determined and standardized to 12% for determination of rough rice yield. RWW larval data were log transformed and all data were subjected to analysis of variance using the GLM procedure of SAS. Experimental and sampling error terms for the RWW larval data were tested for homogeneity of variances, and pooled error terms were used to test the treatment effect when appropriate. Protected least significant difference (LSD) was used for treatment mean separation at 0.05 probability level.

Deposition characteristics and biological effectiveness of fungicides applied to winter wheat and the hazards of drift when using different types of hydraulic nozzles

Hydraulic-fan cone, low-pressure fan and two-chamber cone nozzles were used at 1.5, 3.0 and 6.0 bar (150, 300 and 600 kPa) to deliver 140, 200 and 3001 ha −1 respectively of a fungicide spray to control mildew and yellow rust in winter wheat. No significant differences in biological effect were obtained although fan nozzles deposited significantly more on the upper parts of the stems, and two-chamber cone nozzles deposited less on the flag leaf and on the upper part of the stems. Because of their higher deposit and more even distribution, fan nozzles should be preferred, operated at a pressure of 1.5–3 bar to deliver a spray volume of 140–190 lha −1 at 7 km h −1 and to obtain an acceptable biological effect. Higher pressure (6 bar) and volume rates gave no improvement in fungicide performance. Adding a surfactant or penetration oil did not change the volume median diameter or proportion of spray liquid in droplets < 150 μm. Less drift was found when using two-chamber cone nozzles at 3 bar than with flat-fan spray nozzles at 1.5 bar. It is concluded that the two-chamber cone nozzle is useful for fungicide application when drift must be avoided.

Predicting the transverse volume distribution under an agricultural spray boom

The volume distribution of spray below individual agricultural flat-fan spray nozzles was fitted to a truncated normal distribution. This expresses the parameters as a function of the spray liquid pressure, the boom height and the nozzle orifice size. This model was used to predict the transverse distribution below an agricultural spray boom.

Effects of application methods, spray volumes, pressures and herbicide rates on weed control in spring cereals

Herbicides were sprayed in spring cereals with conventional and low pressure hydraulic flat-fan spray nozzles and rotary atomizers. The biological effects were measured on weeds and oats. In addition, some spray retention studies were performed. Conventional flat-fan spray nozzles at a spraying pressure of 2 or 4 bar (200 or 400 kPa) gave the best effect. There was no difference in effect between spray volumes of 125 1/ha and 250 1/ha. In most field situations, 200 kPa and 125 1/ha should be preferred. However, when the spray volume is reduced from 250 to 125 1/ha, the droplet size decreases and the drift hazard increases. Where great care has to be taken, the use of conventional flat-fan spray or low-pressure nozzles at 100 kPa and 250 1/ha may be a compromise between effect and safety.