Current–voltage characteristics of alternating electric field charger

Charging of liquid droplets or solid particles is widely used in many industrial electrostatic processes such as surface coating or painting, particle separation, scrubbing or two-stage electrostatic precipitation. Employing electrical forces allows improving efficiency of these processes or save energy. The throughput of these processes can be increased by maximizing the charge imparted to the particles and minimising their loss during the charging. This goal can be accomplished by charging the particles in an alternating electric field and ionic current. The rate of particle charging by this type of charger is proportional to the space charge density in the charging zone. The effect of electrode geometry, gas velocity and the frequency of alternating electric field on the space charge in the alternating electric field charger are presented in this paper. The discharge current and the space charge increase with the frequency increasing in the range from 50 to 400 Hz, and next they decrease. The gas velocity has only a slight effect on the discharge current, but a small maximum for gas velocity of about 0.2 m/s was observed.