Practical Experience of the Use of a Continuous Freeness Measurement, 1991 International Mechanical Pulping Conference Proceedings

The traditional method to characterize mechanical pulp is drainage measurement (Canadian Standard Freeness, Schopper-Riegler). Operating personnel of paper mills have learned from experience, how changes in pulp drainage indicate the development of the other pulp properties. Pulp drainage is considered to be a measure of both the operation of the process and the quality of the produced pulp.

Kajaani PDA (Pulp Drainage Analyzer) is a continuous pulp freeness analyzer. First, the sampling device is also used for latency removal is necessary. Then the PDA measures the freeness of the sample compensating for normal consistency and temperature variations.

The accuracy of the PDA analyzer has been tested in different mechanical pulping processes (GW, PGW, and TMP) and the application of the continuous freeness measurement in different mechanical pulping processes is discussed next. The PDA has been utilized to measure the TMP pulp before the latency chest cutting the time delay to make a decision. The other application presented is the use of the PDA to measure the freeness from the PGW grinder.