Electrostatic charging of trigger actuated spray devices

Description/Abstract

Electrostatic charging has long been used to improve the efficiency of a range of sprayed liquids. However, the benefits have not until recently been available for exploitation by domestic sprays due to the need for a high voltage power supply. A minimum charge-to-mass ratio (q/m) of 1  10-4 C/kg is generally considered necessary to elicit electrostatic benefits. This level of charge can now be imparted to liquids atomised from trigger-actuated spray devices by a passive system, requiring no power supply. Induction charging was achieved using a triboelectrically charged aluminium electrode. The q/m of the sprayed liquid was dependent upon the charge residing on the induction electrode. The induction electrode was electrically isolated and required a charge of between 0.7 and 1.3  10-8 C to deliver a water spray with a q/m of 1  10-4 C/kg. This level of static charge was readily attained by tribocharging the aluminium with polythene. Once generated, sufficient charge remained on the electrode surface to charge successive sprays without the need for regeneration. The performance advantages for a spray charged in this manner include attraction to and targeting of surfaces and wrap-around onto surfaces not in the direct line of sight.