Apparatus for charging and collecting submicron particles. The particles are charged by a needle-to-plate ionizer having offset rows of needles which are spaced from the plate such that voltage gradients of 6 KV/cm and higher are achieved. Needle-to-needle spacing and effective area of the plate are...http://www.google.com.au/patents/US4264343?utm_source=gb-gplus-sharePatent US4264343 - Electrostatic particle collecting apparatus
