ID 5

Spray Plume Shaping for an Electrostatic Atomization Nozzle

 

Abstract:

Spraying oil by conventional hydraulic and air-assisted nozzles presents issues with overspray and uneven application. Electrostatic atomization provides an alternative method to spray oils and other electrically insulating fluids, utilizing the repulsive force of like charges instead of high fluid and air pressure. A spray plume of charged droplets provides a very high transfer efficiency when spraying onto grounded conductive substrates. A plane-to-plane electrostatic atomization nozzle produces a full cone spray plume, but for many conveyor coating processes, a flat spray is required to provide a uniform coating across a substrate. In this study, a qualitative approach was taken to investigate the viability of using external plate electrodes to impart an electrostatic force on the charged spray from an electrostatic atomization nozzle to shape the full round cone of droplets into the elliptical cone shape typically found with hydraulic flat fan nozzles. It was found that both parallel and angled external electrodes shaped the spray plume into the desired flat fan shape and accelerated the spray plume away from the nozzle. Testing was conducted using a laser sheet to illuminate and a DSLR camera to capture the droplets passing through a small slice of the spray plume normal to the axis of the nozzle. Patent Pending.