Abstract: In a process and apparatus for pneumatically conveying loose material in grain or dust form by discharge thereof from a conveyor container, through a conveyor conduit disposed downstream thereof, after the conveyor container has been emptied and before the conveyor conduit is also emptied of the loose material being conveyed, the conveyor conduit is closed at both ends, to maintain that existing condition. After the conduit is thus closed off at both ends, leakage losses of conveying gas are compensated for by supplying a leakage make-up amount. The apparatus has a conveyor conduit which is provided at each of its end portion towards the conveyor conduit and its discharge end portion with at least one closure member to act as inlet and outlet valves respectively. At least one gas feed line from a leakage make-up valve opens into the conduit.