Patent ID: 7901541

Claim:
A method for the impregnation of chips during the manufacture of chemical pulp, comprising: continuously feeding chips, without a preceding steam treatment, to a top of an impregnation vessel, the chips establishing a chips level, feeding at least 5 tonnes of an impregnation fluid per tonne of chips into the impregnation vessel, the impregnation fluid establishing a fluid level, the chips level being at least 1-2 meters above the fluid level, the impregnation fluid having a temperature in an interval of 115-150° C. and an alkali level exceeding 15g/l, establishing a pressure within the top of the impregnation vessel that is essentially at atmospheric pressure ±0.5 bar and a temperature in a range of 15-25° C., and establishing a fluid-wood mixture at the fluid level having a temperature within an interval of 90-115° C., and feeding out impregnated chips from a bottom of the impregnation vessel.