Removal of Electrostatically Deposited Powders Using High Intensity Low Frequency Sound, Part 2: Quantification of Adhesive and Cohesive Forces Using Vibration

Abstract

This is the second of two papers on the controlled removal of electrostatically deposited powder deposits. The research has an industrial application, the cleaning of electrostatic precipitator (ESP) filters in coal-fired power stations. The first paper focused on the removal of powder layers from a metal surface using sound. The aim of the work, reported in this paper, is to quantify the adhesive and cohesive bonding forces formed when powder is electrostatically deposited on to a metal surface by removing deposited layers using vibration. It is these forces that sound must overcome in order to remove deposited layers. It is hoped to establish a link between the layer de-bonding acceleration and de-bonding sound pressure level. Powder layers were electrostatically deposited on to one surface of an aluminium cube. The deposited layers then were removed, using a calibrated vibration table, in order to estimate powder bonding forces.