A method of pneumatically feeding material in succession, through separators, to receiving stations, with conveying air being discharged from the system only at the last separator in the circuit. Conveying is stopped when the material reaches a predetermined level in the last separator, but commences again when the material falls below that level, which can be achieved by feeding material back through the conduit to the feed station. The apparatus has a series of separators, the last of which filters out exhaust air, with valves responsive to the level of material in the last separator or a pressure rise in the conduit, to stop conveying and to blow back through the conduit to clear the last separator.