DRAINABILITY CANADIAN STANDARD FREENESS

This test is performed to determine the drainability of a pulp according to the Canadian Standard Freeness method.

Operate the instrument in accordance with ISO 5267-2 and the manufacturer’s instructions.

Soak one filter pad sample (approximately 24 g of dried pulp) at least 4 h in 1200 ml of distilled water at 20°C (alternatively, use standard water according to ISO 14487; at 25°C conductivity ≤0.25 mS/m).

Dilute to 2000 ml (1,2% consistency) with distilled water/standard water at 20°C and disintegrate for 30.000 revolutions.

Make sure that no fibre bundles remain by visual examination of a diluted sample portion, otherwise repeat the process until only individual fibres remains.

Take a sufficient portion of the disintegrated pulp and determine its consistency by filtering and drying at 105°C±3°C.

Dilute the pulp suspension to a stock concentration of 0,30±0,01% by mass and adjust the temperature to 20,0±0,5°C.

Throughout the sample preparation care should be taken to avoid the formation of air bubbles in the suspension.

Allow no more than 30 minutes from pulp disintegration to freeness determination to avoid change in pulp freeness.

Read the volumes to the nearest 1ml for values below 100 ml, to the nearest 2 ml for values between 100 and 250 ml, and to the nearest 5 ml when exceeding 250 ml.

Report 5 measures in SR units, their mean and standard deviation calculated to 3 significant figures.