Studies on Spray Tank Agitation in the Use of Oil Sprays

Abstract

Tests made of 18 orchard sprayers with tanks ranging in capacity from 200 to 465 gallons, with agitator paddles of various kinds and sizes ranging in number from three to five per tank, and with agitator speeds ranging from 60 to 300 r.p.m., indicated that the speed of the agitator is the most important factor in efficient agitation in the use of oil sprays. With the average tank and agitator equipment a speed of approximately 225 r.p.m. was found to be sufficient to maintain a uniform mixture of pure oil and water in the tank. Taking into consideration the fact that the so-called quick-breaking emulsions commonly contain much unemulsified oil, that the oil in the dilute spray quickly rises to the surface if the agitation is interrupted, and that stable emulsions, including miscible oils, tend to break when used with hard water, an agitator speed of approximately 225 r.p.m. is believed to be advisable for tanks in which oil sprays are used. Tables are given showing the effect of emulsifiers, size and number of paddles and agitator speed on the uniformity of the mixture of the oil and water. An improved method is given for determining the oil strength of sprays.