A fiber bed assembly for a fiber bed mist eliminator used to remove aerosols from a moving gas stream, the fiber bed assembly comprising: a fiber bed support having a wall comprising a cylindrical inner screen and a cylindrical outer screen, the inner screen and the outer screen being circumferentially arranged with respect to a longitudinal axis, the wall defining an upstream space outside the outer screen and a downstream space inside the inner screen, the wall including openings therein to permit the gas stream to move generally freely through the wall from the upstream space to the downstream space; a fiber bed supported by the fiber bed support and generally blocking the wall openings so that the gas stream passes through the fiber bed moving from the upstream space to the downstream space, the fiber bed comprising collecting fiber media and having a top, a bottom, an upstream surface and a downstream surface; characterized by a base comprising an air impermeable top wall (124, 174) extending in a radial plane with respect to the longitudinal axis, a cylindrical side wall projecting down from the top wall and in generally opposing relation with a portion of the downstream surface of the fiber bed for blocking the flow of the gas stream from the fiber bed into the downstream space through said downstream surface portion, a flange (130, 750) extending in a radial direction under the lower end of the screens (66, 68) and the lower end of the fiber bed and a leg extending downwardly from the top wall of the base, the leg having a passage therein for draining collected aerosols collected by the fiber bed assembly, the passage being packed with a fibrous packing material having a density greater than the density of the fiber bed. a fiber bed support having a wall comprising a cylindrical inner screen and a cylindrical outer screen, the inner screen and the outer screen being circumferentially arranged with respect to a longitudinal axis, the wall defining an upstream space outside the outer screen and a downstream space inside the inner screen, the wall including openings therein to permit the gas stream to move generally freely through the wall from the upstream space to the downstream space; a fiber bed supported by the fiber bed support and generally blocking the wall openings so that the gas stream passes through the fiber bed moving from the upstream space to the downstream space, the fiber bed comprising collecting fiber media and having a top, a bottom, an upstream surface and a downstream surface; characterized by a base comprising an air impermeable top wall (124, 174) extending in a radial plane with respect to the longitudinal axis, a cylindrical side wall projecting down from the top wall and in generally opposing relation with a portion of the downstream surface of the fiber bed for blocking the flow of the gas stream from the fiber bed into the downstream space through said downstream surface portion, a flange (130, 750) extending in a radial direction under the lower end of the screens (66, 68) and the lower end of the fiber bed and a leg extending downwardly from the top wall of the base, the leg having a passage therein for draining collected aerosols collected by the fiber bed assembly, the passage being packed with a fibrous packing material having a density greater than the density of the fiber bed.