Abstract: A method and apparatus for filling a treatment vessel, such as a digestor, with fiber material and liquid. A chips-liquid mixture from a pretreatment vessel is fed through a conventional feeding valve to a treatment vessel while the chips-liquid mixture is being acted on by other means in the feeding valve. The feeding valve includes a rotor having a number of pockets extending therethrough, and a plurality of inlets and outlets arranged around the periphery of the valve for communication with the pockets thereof. In a first position of the valve chips-liquid mixture is fed into a pocket, and a portion of the liquid is strained off, then the valve rotates to a second position wherein a quantity of the liquid is displaced by gas or steam while the chips are maintained in the pocket, and then the valve rotates to a third position wherein the chips in the pocket are discharged into the treatment vessel.