GB204361A - Process of and apparatus for electrically separating suspended particles from electrically non-conducting, especially gaseous fluids - Google Patents

Abstract

204,361. Lodge-Cottrell, Ltd., (M÷ller, E.). May 25, 1922. Gases and vapours, electrically precipitating suspended particles from.-Precipitators employed in multiple-stage electric gas purification are arranged so that in successive stages the current density and in some cases the electric field are increased in the neighbourhood of the collecting electrodes. In one method, the spacing of the electrodes is reduced and the electric pressure increased in parts B<1>, C<1> of the apparatus reached later by the gases; the pressure may approach closely to the disruptive limit, which may be raised by increasing the auxiliary field surfaces 3b<1>, 3c<1>, and by constructing these and the discharge electrodes so as to avoid sparking, e.g. by rounding-off, grooving at the edges, or making parts of oval cross-section. Alternatively, the electrode distance may be kept constant or increased in the later stages, and the current density increased near the collecting electrodes by increasing the voltage and providing more numerous field surfaces. The discharge electrodes 1b<1>, 1c<1> for later stages may have diameters decreasing either absolutely or relatively to the electrode distances. The initial treatment may be effected by positive discharges from a " pubescent " electrode 1a<1> and the subsequent treatment by a negative corona discharge; or where current is to be small, the initial treatment may be with a positive brush and the later treatment with a positive glow discharge. It is advisable to increase in the later stages, the partial current volumes," i.e. the total space which would be occupied by ionic discharges if dust were absent. In some cases, however, the " partial current volume " may be greater in both the initial and final stages than in the intermediate one. Specifications 17840/12, 19733/13, and 17175/14 are referred to.