METHOD AND APPARATUS FOR WORKING UP A SAMPLE OF LIQUID

摘要

Method and apparatus for working up a sample liquid of a pulp and paper industry process water, such as pulp slurry or white water. The sample is worked up in an apparatus including a sample flow chamber, a filtrate flow chamber and a filter connecting said sample flow chamber with said filtrate flow chamber. According to the invention, a flow of sample liquid, including solid substances, such as fibers and filler materials, as well as dissolved and colloidal substances, is introduced through an inlet (12) into the sample flow chamber (10). A main flow of this sample liquid is discharged through an outlet (14). A flow of filtrate is passed through a filter (16, 16') from the sample flow chamber into the filtrate flow chamber (20), thereby separating in the filter from a minor portion of said introduced flow of sample liquid a predetermined fraction of solid substances. The minor portion of sample liquid corresponding to < 1 %, typically < 0.1 % of the total introduced flow of sample liquid. A mat of solid substances is prevented from building up on the inlet side of the filter by inducing in the sample flow chamber turbulence or a high flow velocity of sample liquid adjacent the filter.