Abstract: A corrosion resistant electrostatic precipitator has an array of tubular collector electrodes with a cylindrical casing, the tubular collector electrodes and casing each having a surface resistivity of the order 10.sup.6 ohms. The walls of the collector tubes, in preferred form, are a lamina comprising, in order from the inner surface outwardly, an innermost resin impregnated with graphite followed by a conductive metal mesh, another layer of resin impregnated with graphite, a fiberglass veil (corrosion resistant barrier), a layer of fiberglass mat, a layer of fiberglass roving, another layer of fiberglass mat, another layer of fiberglass roving, and finally an outer layer of fiberglass mat. The wall of the cylindrical casing is also a lamina whose make-up is generally similar but not identical to the walls of the collector tubes. Means are provided for grounding the conductive metal mesh which is embedded in the collector walls and in the casing wall.

Abstract: A modular gas and liquid contact member is formed of a plurality of extended surface sheet members with means associated with at least the peripheral margins thereof warping the sheets and maintaining the sheets in an undulated array. In a preferred form of the invention, the means for warping and maintaining the sheet members in the undulated array comprises a plurality of through bolts and spacers of varying lengths threaded on the through bolts and contacting opposed surfaces of adjacent sheet members.