SPRAY SPECTRA, DEPOSITION AND SEDIMENTATION CHARACTERISTICS FOR LOW PRESSURE LIQUID ATOMIZERS

Abstract

The focus of this investigation was on assessing the feasibility of the evaluation new developing nozzles that will target and spray the biological pest control materials and herbicides. As well as comparing the spray characteristics for external mixing twin fluid nozzles with the low liquid atomizers motorized Backpack mistblower and ProptecTM rotary atomizer. The Stihl SR 340 Powerful knapsack Mist-blower 2.6 kW, rotary atomizer, Ledebuhr Industries, Inc. 11429 Upton Road Bath, Michigan-48808) and five developed an external mixing twin fluid (EMTF) nozzles were tested under laboratory condition to measure the spray droplet spectra, the spray deposition and sedimentation. Droplet size spectra produced by three atomizers, mistblower, rotary cage and EMTF nozzles were measured using the Malvern laser (particle size analyzer). The three atomizers were tested at flow-rate 0.5 l min -1and 1 l min -1. As well as, the motorized Backpack Mistblower and ProptecTM rotary cage atomizer were tested under four levels for rotational speed. The rotational speeds for ProptecTM Rotary cage atomizer were 3000 r.p.m, 3500 r.p.m 4600r.p.m and 5000 r.p.m; and its were 3000 r.p.m, 4000 r.p.m, 5000 r.p.m and 6000 r.p.m for Backpack Mistblower. On the other hand, the five EMTF nozzles were tested at 150 kPa air pressure. The three atomizers was operated at low various pressures, five external twin-fluid nozzles at 30 kPa , mistblower at 28 kPa and rotary atomizer at 90 kPa liquid pressures. The different atomizers were compared by using the spray spectra, spray deposition and spray sedimentation parameters. The result indicated that, the rotary cage atomizer generally gave droplet spectra with lower Dvo.1 , D vo.5 and Dvo.9 values than the Backpack motorized Mistblower and the five EMTF air-shear nozzles. The ProptecTM rotary cage atomizes gave very fine droplets spectra with higher deposition than the Backpack mistblower and the five EMTF air-shear nozzles. The spray spectra D0.1, Dv0.5 and D0.9 for EMTF nozzles at 0.5 l min -1 flow rate were 42.7 µm, 100.9 µm and 195.4 µm; and 46.7 µm, 107.0 µm and 206.1 µm for both N3 and N5 respectively. The deposition percentage for N3 (Lechler FT 5 – 608 + Lechler LU 120-015 POM) and N5 (Lechler FT 5 - 608 + Tee Jet XR8004 VK) were 57.7 % and 58.8 % at flow-rate 1.0 l min-1. The sediment percentage for N3 (Lechler FT 5 – 608 + Lechler LU 120-015 POM) and N5 (Lechler FT 5 - 608 + Tee Jet XR8004 VK) were 16.3 % and 14.6 % at flow-rate 0.5 l min-1.