Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Wind Tunnel Evaluation of Spray Drift from Flat Fan Hydraulic Nozzles for Contributing Physical Factors

M K U Sarkerr
Assistant Professor
Dept. of Farm Mechanics, Hajee Mohammad Danesh Science & Technology University,Dinajpur, Bangladesh.

C S Parkin
Chemical Application Specialist, Silsoe Research Institute, Bedford, Beds, England, UK.

Abstract/ Executive Summary:

Spray drift is one of the important hazards in pesticide applications from hydraulic nozzles. The main contributing factors for spray drift are nozzle types and sizes, nozzle pressure, wind speed, height of the spray nozzle above the target crop, spray liquid properties and direction of spray sheet with respect to the travel of the sprayer. Influence of the above factors on drift potential has been studied at the spray laboratory of Silsoe College (Cranfield University, UK). A low speed suction type wind tunnel having 7m working length, 2m width and lm height was used for the experiments. The proportion of spray displaced 2m downwind from the nozzle was measured using 2mm o.d. polyethylene line drift collectors and a fluorescene technique. The spray liquid used was 0.1 per cent Agral concentration corresponding to the surface tension of 50 mN/m. The experimental results revealed that spray drift can be significantly reduced by using reduced drift nozzles compared to the standard flat fan nozzles, by lowering the nozzle pressure, by lowering the nozzle height, by spraying directly towards the target and spraying at low wind speed.

Keywords: Physical factors, Spray applications,Spray

Location: Dept. of Farm Mechanics, Hajee Mohammad Danesh Science & Technology University, Dinajpur.

Start Date:

End Date:

Program Area: Farm Mechanization

Commodity: Sprayer

Objectives:

1.To improve the efficacy of spray applications and

2. To detect the factors and conditions reducing drift.

Methodology:

Spray Liquids : The test liquids used for experiments was 0.1 per cent v/v aqueous solution of Agral, a nonjinic surfactant (ICI, UK), corresponding to dynamic surface tension of the Liquid 50 mN/m and close to the usual spray materials applied in agriculture.Wind tunnel and spray system: The Silsoe College Low-speed suction type wind tunnel was used in the experiments . The tunnel was of 7m working length, 2m wide and 1m high. A general wind speed of 2.63 m/s was used for the tests except for those conducted to assess the effect of wind speed on spray drift. A nozzle was mounted on a boom 2m downwind of the tunnel floor. The floor was covered with artificial turf to prevent drop re-entrainment and the section directly under the nozzle was fitted with a small sump to collect the majority of the spray liquid leaving the nozzle. The spray system consisted of a 10L pressurized container delivering liquid to the boom through a solenoid valve. The solenoid valve was operated by an electronic timer that was set to provide a spray period of 10 seconds.Drift measurements: The spray was traced using a standard fluorescence technique (Merrit, 1989). Spray solution contained 0.1 per cent (W/v) sodium fluorescence. Airborne spray was sampled downwind of the spray nozzle using 2 mm o.d. polyethylene tubing stretched across the tunnel at 100 mm height intervals. The fraction of the spray airborne downwind of the nozzle or Drift Potential (DP) was calculated from the dimensions of the collectors, the duration of the spray, the nozzle discharge and the tracer collected on the sample. DP was measured at different pressure levels (P), different height of the nozzle (H) above the tunnel floor, different nozzle sizes and types, different distance of drift collection from the nozzle, different wind speeds (U) and different orientation of the spray sheet with respect to the wind directions (0). To compare the impact of nozzle types and sizes on spray drift, standard flat fan nozzles and reduced drift fan nozzles (Castel, 1993) with similar equivalent size and flow rates were studied in the same study. The experimental design for the studies of the above factors are shown.

Source of Information: Journal of the Institution of Engineers, Vol-30/AE, No-1 Dec-2003

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

From the experimental study, it could be concluded that drift could be minimized to a remarkable extent by controlling the contributing physical factors. To minimize spray drift in field operations, it would be advisable to use bigger nozzles appropriate for the applications at lower pressure preferably below 2 bar. Dual orifice reduced drift nozzles are better options compared to standard flat fan nozzles for drift control. Spraying height should not be above 50 cm from the target crop and the nozzle spray direction should be downwards to the target, obviously at lower wind speed preferably not above 2m/s. Combining the above conditions, more than 70 per cent drift reduction is possible than used traditionally.

Knowledge Management: Journal