Removal of Electrostatically Deposited Powders Using High Intensity Low Frequency Sound Part 1: Experimental Deposition and Removal

Abstract

This paper describes the controlled removal of powder layers using high intensity low frequency sound. The research has an industrial application, the cleaning of electrostatic precipitator filters in coal-fired power stations. The aim of the work is to quantify the sound pressure level and frequency content required to overcome adhesive and cohesive bonding forces formed when powder is electrostatically deposited onto a metal surface. In this, the first of two papers, a repeatable method for electrostatically depositing powder layers on to a metal surface is described. The design, construction and calibration of a high intensity wave tube also are described. The measured sound pressure level required for removal is compared with prediction. Measurements in a reverberant acoustic field using commercially available acoustic cleaning systems also are reported.