Metering Concentrated Pesticides

ABSTRACT THE use of direct injection of concentrated pesticides into sprayer systems shows promise if the flowrate can be measured and controlled. The effect of temperature on density, viscosity, and flowmeter response is required in order to design components of an automatic sprayer injection and control system. The density, viscosity, and drag-body flowmeter response were measured for commercial formulations of five pesticides. Densities ranged from 1.015 to 1.105 g/cm3. The change in density was small when the pesticide was subjected to a 22 °C temperature change. The viscosities ranged from 1.2 to 33.0 mPa-s at a shear rate of 1,000 s1. Pesticide temperature affected the accuracy of the drag-body flowmeter in sensing the flowrate. The drag-body flowmeter response was accurate provided that pesticide temperature was held constant and calibration constants were determined for each pesticide temperature combination.