Measurement of the particle space charge in the outlet of an electrostatic precipitator using an electric field mill

It is shown that for certain conditions the concentration of the escaping particles can be related to the space-charge field in the outlet duct. The theory of operation along with a discussion of the sensitivity of the method is presented. The design and performance characteristics of a self-purging field mill are described and preliminary measurements based on field testing are reported. The results of three preliminary tests carried out in an industrial environment confirm the usefulness of the device for monitoring instantaneous emission levels.<
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