drawn off from the treatment vessel 3 via the withdrawal strainer sc 3 and sent to recovery rec if necessary white liquor wl may also be added to the vessel 3 for example as shown in the figure to line 41 the actual remaining alkali content depends on the type of wood used hardwood or softwood and which alkali profile that is to be established in the digester in the case where a raw wood material that is easy to impregnate and neutralize is used for example raw wood material such as pin chips or wood chips with very thin dimensions and quick impregnation vessel 3 may in extreme cases be a simple spout with a diameter essentially corresponding to the bucket formed outlet 10 in the bottom of the vessel required retention time in the vessel is determined by the time it takes for the wood to become so well impregnated that it sinks in a free cooking liquor after the chips have been processed in vessel 3 they are fed out from the bottom of the vessel where also a conventional bottom scraper 4 is arranged driven by a motor m 1 according to the invention the chips are fed to the digester via at least 2 pumps 12 a 12 b in parallel and these pumps are connected to a bucket formed outlet 10 in.