A filter apparatus includes a gas-impermeable outer conduit having an open end and a closed end. The interior of the outer conduit is axially divided into first and second sides. A first clean and first dirty flow path are defined within the first side. A first gas-permeable liner separates the first clean flow path from the first dirty flow path and from the open end. A second clean and second dirty flow path, are defined within the second side. A second gas-permeable liner separates the second clean flow path from the second dirty flow paths and from the open end. A control valve connects one of the first clean and second clean flow paths to an exhaust conduit, and connects the other clean flow path to a selectively pulsed supply of cleaning gas.