Patent ID: 8691050

Claim:
A method for transferring particulate and/or fibrous feedstock from a zone 1 with lower temperature T 1 and a lower pressure P 1 into a zone 2 having a higher temperature T 2 and a higher pressure P 2 , wherein P 2 mainly derives from vapour which will condense at T 1 , comprising compaction of said feedstock in a flow feeder chamber to form a moving plug having a density at which vapour from P 2 can penetrate said moving plug, forming a condensation front that moves at a controllable velocity towards P 1 into said plug, counter-current to the motion of said plug which is from P 1 towards P 2 , and avoiding leakage of vapour from P 2 to P 1 by adjusting the velocity at which said condensation front moves towards P 1 into said plug relative to the velocity at which said plug moves from P 1 to P 2 .