The conventional view implied in the term "electrostatic precipitation" is that dust
particles become charged from the corona current and then are attracted by electrostatic
forces to the collector plates for precipitation. However, we have come to the view that a significant mechanism in sweeping the dust particles both to and from the
plates is that of corona wind. We have performed measurements of the corona wind
in a model precipitator using an optical fibre anemometer. We obtain velocities
of the order of 2 m/s for the corona wind associated with voltages of 50 kV on a conventional
electrostatic precipitator wire, which is of the same order of the usual imposed
flow velocities of 1 m/s. Approximate calculations of the corona wind obtained from the momentum transfer
from the ions of the corona current also give corona wind currents of the order of
1 m/s. In addition we have performed two dimensional fluid dynamic calculations incorporating
corona wind with an imposed cross flow. An improved design of the plate configuration
of electrostatic precipitators is suggested to utilize the effect of corona wind to assist the transport of particles to the plates.