Evaluation of Different Internal Designs of Hydraulic Nozzles under an Accelerated Wear Test

The use of worn-out agricultural nozzles in pesticide application has a negative effect on the efficiency and cost of the application process. It also has an effect on environmental pollution due to an excessive amount of pesticide being applied when spraying with worn-out nozzles. In this paper, the resistance to wear of three different internal design hydraulic nozzles was ascertained. Changes in the flow rate and spray distribution as a result of this wear were also investigated. The wear test was done inside a closed system, and it was accelerated using an abrasive material to generate 100 h of wear. The tested nozzles were the Turbo TeeJet (TT)-twin chambered, Turbo Twinjet (TTj60)-dual outlet, and Drift Guard (DG)-pre-orifice. Wear rate, flow rate, and the virtual coefficient of variation (CVv) were measured at different wear intervals. The results showed that the TTj60 type was the most resistant to wear, followed by the TT type and DG. The latter two types showed an increase in the flow rate only in the first 45 h of wear. Virtual coefficient of variation (CVv) values were less than 10% after finishing the test (after 100 h of wear) for the three types of nozzles, which are acceptable values according to International Organization for Standardization (ISO) 16122-2, 2015.

A probabilistic model for estimating ocean-spray distribution in extreme tropical cyclone winds

ABSTRACT. Serious gaps in knowledge about ocean spray at wind speeds over 28 m/s remain difficult to fill by observation or experiment; yet refined study of the thermodynamics of Tropical Cyclones (including typhoons and hurricanes) requires assessment of the hypothesis that ‘spray cooling’ at extreme wind speeds may act to reduce (i) the initial temperature of saturated air rising in the eyewall and so also (ii) the input of mechanical energy into the airflow as a whole. Such progressive reductions at higher speeds could, for example, make any possible influence, of future global warming on Tropical Cyclone intensification largely se1f-limiting. In order to help in extrapolation of knowledge on ocean spray to extreme wind speeds, a probabilistic analysis is introduced which allows for the effects of gusts, gravity and evaporation on droplet distributions yet all other respect is as simple as possible. Preliminary indications from this simplified analysis appear to confirm the potential importance of spray cooling.

Research of design solutions of water cooling systems for tanks

Установки водяного охлаждения резервуаров являются частью системы автоматического пожаротушения резервуарного парка и представляют собой комплекс устройств, оборудования и трубопроводов. Непосредственное охлаждение стенки резервуара осуществляется через верхнее горизонтальное кольцо орошения, выполненное в виде перфорированного трубопровода или трубопровода с оросителями. При этом до настоящего времени не была определена зависимость фактически защищаемой площади стенки от расходов воды, подаваемой через отверстия и/или оросители при их различном положении по отношению к стенке и верхней кромке резервуара. Цель исследования - экспериментальное определение оптимальных конструктивных и технологических решений элементов установок водяного охлаждения резервуара. Для изучения процессов теплового нагрева и охлаждения боковой поверхности резервуара проведены гидравлические и огневые испытания моделей секции установки водяного охлаждения - горизонтального кольца орошения. По результатам испытаний определена эффективность различных конструкций в зависимости от изменяемых технологических параметров (давления и расхода воды в кольце орошения), диаметра отверстий перфорированного трубопровода и шага между ними, угла расположения устройств подачи воды относительно горизонтальной поверхности сечения резервуара, расстояния от кольца орошения до стенки резервуара и его верхней кромки. Water cooling units for tanks are a part of automatic fire extinguishing system of the tank farm and represent a complex of units, equipment and pipelines. Tank wall is cooled down directly through upper horizontal spray distribution ring, made in the form of a perforated pipeline or a pipeline with sprinklers. With this, correlation between actually protected area of the wall and flow rate of water supplied through the holes and/or sprinklers at their different positions in relation to the wall and the upper edge of the tank, has not been determined so far. The purpose of the study is to experimentally determine the optimal design and technological solutions of the elements of tank water cooling units. To study the processes of thermal heating and cooling of the side surface of the tank, hydraulic and fire tests of models of the section of the water cooling unit (the horizontal spray distribution ring) were carried out. According to the test results, the efficiency of various structures was determined depending on the technological parameters being changed (pressure and water flow in the spray distribution ring), diameter of the holes of the perforated pipeline and pitch between them, angle of the water supply units relative to the horizontal surface of the tank section, distance from the spray distribution ring to the tank wall and its upper edge.

Volume Rate Adjustment for Pesticide Applications against Aonidiella aurantii in Citrus: Validation of CitrusVol in the Growers’ Practice

Aonidiella aurantii is one of the most damaging armored scales in citrus crops worldwide. To control this pest, high water volume rates are conventionally used. In order to rationalize the pesticide applications in citrus, IVIA developed CitrusVol, a tool that recommends the optimal volume rate based on the vegetation, the pest or disease and the active ingredient. In this study the objectives were: (i) validate CitrusVol as a tool to adjust the spray volume to control A. aurantii and (ii) quantify its environmental and economical advantages. For this, the spray volume adjusted with CitrusVol was compared with the one conventionally used by farmers in 18 applications in seven orchards during two years. The following parameters were evaluated: (i) spray distribution in the canopy, (ii) A. aurantii males trapped per day, and (iii) number of scales per fruit at harvest. CitrusVol reduced the spray volume and the amount of pesticide by 35% on average. Despite this reduction, a satisfactory spray distribution was achieved, and the volume was found to control the pest in a comparable way to the conventional volume. Moreover, CitrusVol saved per application and on average 31.25 h/100 ha of spray operating time, 241.83 L/100 ha of fuel consumption and consequently, the reduction of emissions of CO2 was 631.18 kg/100 ha. Therefore, CitrusVol allows for efficient, low-input and low-impact pesticide applications.

Evaluation of the Effect of Different Hand-Held Sprayer Types on a Greenhouse Pepper Crop

The cultivation of vegetables in greenhouses is characterised by high planting density and environmental conditions that favour the development of pests and diseases. These are mainly controlled using plant protection products applied with a hand-held sprayer. This is inefficient low-tech equipment that is difficult to calibrate. The study evaluates one hand-held spray gun and two hand-held spray lances that are widely used in greenhouse vegetable crops. The tests were carried out on a pepper crop at two different developmental stages. Plant canopy deposition and losses to the ground were quantified using a colorimetric method based on applying a tartrazine solution. The results show that the flat-fan spray lance obtains a more uniform spray distribution in the plant canopy and results in losses to the ground that are between 2 and 2.75 times less than when using the other hand-held sprayers tested.

Evaluation of Horizontal Patternators According to International Standard Requirements for Boom Sprayers

HighlightsHorizontal distribution according ISO Standard 16119 is a measurement procedure to evaluate boom sprayers.ISO Standards 5682-1 and 5682-2 establish technical requirements for horizontal patternators.In this study, three types of patternators were evaluated to test their capability to meet the standards.The evaluated patternators showed similar results for spray distribution patterns.Minor deviations from ISO Standard 5682 did not imply differences according ISO Standard 16119.Abstract. Uniformity of spray volume distribution is one of the officially established measurements for the evaluation of horizontal boom sprayers according to ISO Standard 16119 and requirements established by ISO Standard 16122. Measurement of spray distribution patterns requires the use of specific devices such as horizontal patternators, which are included in the technical specifications for ISO Standards 5682-1 and 5682-2. Three such devices were tested, including two manual patternators (fixed and mobile) and one electronic patternator. According to information provided by the manufacturers, all three patternators align with ISO requirements. This study evaluated and compared the results obtained with the three patternators. Specifically, the horizontal distributions measured by the patternators were evaluated and compared using four nozzle types (XR 11003, AIXR 11003, TTJ60 11003, and AITTJ60 11003), three boom heights, and three operating pressures. Tests were conducted to quantify single-nozzle spray patterns, the coefficient of variation (CV) of the entire boom distribution, the liquid recovery capability of the three patternators, and the ability to simulate the entire boom spray distribution from a single-nozzle spray pattern. Results demonstrated correct functioning of all three patternators, resulting in identical conclusions considering the requirements established in the ISO standards. The CV values of the horizontal distributions were less than 10% for all cases. Moreover, the trends in values for all the evaluated factors (nozzle type, boom height, and operating pressure) were the same, independent of the patternator used. Keywords: ISO 16119, ISO 16122, ISO 5682, Liquid recovery, Nozzle spray pattern, Patternator, Spray boom, Transverse distribution, Uniformity.

Design and Development of an Indoor Testing Facility for Downwash and Spray Distribution Evaluations of Agricultural UAV

The usage of UAV as a pesticide application technology is becoming a common practice in South East Asia with a very significant proportion of agricultural areas have now being treated using such method. Up to date, about more than 169 of various designs and configurations of UAV have been produced to cater the demand, however it is in doubt whether all these available models were optimally integrated with the spray systems to give the required spraying qualities. Despite of each UAV configuration has their own unique aerodynamic effects, it is crucial to determine their downwash airflow patterns, the spray distributions and the effective application parameters that could give high spraying quality. This research outlines the development of an indoor testing facility and its standardised testing procedure for evaluating the spraying performances of any model UAVs that are used in agricultural applications. The testing facility was developed to imitate the UAV in the actual field spraying operation. With 23 m travel length, the developed testing facility was designed to carry the test UAV up to 100 kg, adjust the test UAV at three levels of spraying heights (1.5, 2.5, and 3.5 m), and moves the test UAV up to a maximum travelling speed of 10 m/s. The 6x6 m sampling platform structure for the pressure sensors and water sensitive papers was built underneath the rail support structure to measure and collect data for spraying distributions and downwash 3D profile spectrum. With the availability of this indoor UAV Testing Facility, it is expected that any efforts to increase the spraying efficiency using UAV could be tested repeatedly with same standard protocols, so that proper recommendations could be made on the flying requirements of the UAV in order to achieve an efficient agricultural chemical spraying operation.