or to an upper part of an inverted top separator in accordance with our patent u s pat no 6 214 171 b1 in order thereby to accompany the chips down into the digester 6 the impregnation liquor q imp then comes directly to constitute cooking liquid in the subsequent cooking zone 3 if necessary direct steam q steam can be added in a conventional manner to the top of the digester 8 for the purpose of adjusting the temperature the process according to the invention can also be employed in hydraulic digesters in which the extraction of the impregnation liquor from the transfer circulation can take place in a conventional screen section at the top of the digester or at the bottom of the impregnation vessel for subsequent handling in line with what has been described above in yet another variant the invention can be applied to a process in accordance with that in wo001261 in which hemicellulose rich impregnation liquid is conveyed to a final cooking zone for precipitating xylan in the final stage of the cooking as has previously been explained this can give rise to problems with shives in the pulp which problems arise when chip pieces which accompany the impregnation liquid are not given sufficient time for delignification applying the present invention to this impregnation liquid provides a method for remedying this problem providing the impregnation liquid together with any chip pieces which may be present with a minimum dwell time before it is returned to the digester of 30 u2013 120 minutes preferably 45 u2013 90 minutes or a time which corresponds to the.