15 March 2002

SPRAY TIPS: 2

INDUCTION HOPPER

Wise use of an induction hopper can lead to win-win results. Contamination risk for the operator and environment is minimised, clambering up to fill the tank through the top is avoided, pack handling is at a convenient height and rapid mixing of the chemical as it enters the tank is achieved. All make for better spraying.

"It is best to start with only 10% of the tank filled with water," says Tom Robinson, application specialist with Syngenta. "This allows time to get your chemicals in while the sprayer is filling. But be sure to put an absorbent material or catch bowl under the hopper for any accidental drips of concentrate. And dont throw foil seals down".

The induction bowl should not be contaminated, especially if the previous spray contained a sulfonyl urea. Open the control valve to allow a steady flow of water. "Add the chemicals steadily to encourage even mixing as they pass through the venturi and never add two products at the same time," says Mr Robinson.

Pour liquids carefully to avoid glugging. Some hoppers allow for closed transfer filling with compatible packs, which helps overcome that problem.

The sequence of adding products is important. If there are no firm instructions on the product labels, work according to formulation. Start with solids WSB>WG>WP, then liquids SC>SE>EW>EC>SL, then adjuvants and lastly micro-nutrients or foliar feeds.

In addition to liquid formulations, water soluble granules and other solid formulations can be successfully introduced through a part-filled induction hopper, although some may need pre-creaming.

Always let the bowl flush out after the last addition and never allow it to run dry, otherwise air may be sucked in and cause frothing.

Most induction hoppers have pack rinsing systems. These greatly improve pack cleaning.