AS NZS 1301.209:2017 pdf free.Methods of test for pulp and paper Method 209: Laboratory processing of pulp— PFI mill method.
7.2 Thickening
After disintegration, drain the pulp suspension on a Büchner funnel or other suitable device to a mass fraction between 11 % and 20 %. To avoid any loss of fibres, refilter the filtrate through the fibre mat, if necessary several times.
Using a balance, dilute the thickened pulp with standard water (4.4) to a total mass of (300 ± 5) g, corresponding to a mass fraction of 10 % stock.
7.3 Beating
7.3.1 Beating conditions
Check that the beating conditions are correct (see A.2).
The beating force per unit bar length shall be (3,33 ± 0,10) N/mm, assuming that only one bar at a time makes contact with the housing. It is important that the distance screw is disengaged during beating, i.e. no fixed gap shall be used.
Experience has shown that, for some pulps, a lower beating force per unit bar length may be needed to be able to evaluate the physical properties of the pulp in a correct way. In such cases, the beating force per unit bar length could be (1,77 ± 0,10) N/mm. This deviation from the standard procedure should be reported.
7.3.2 Beating procedure
Bring the beating elements of the PFI mill (4.1) and the thickened test portion of pulp, prepared in accordance with 7.1 and 7.2, to a temperature of (20 ± 5) °C (see Note to 7.1). Transfer the test portion of pulp to the beater housing, and distribute it as evenly as possible over the wall. A uniform band of pulp will ensure a smooth start-up, thus reducing unnecessary vibrations and attaining a more stable beating. Ensure that no pulp remains on the bottom of the beater housing within an area corresponding to the cross-section of the roll. Insert the roll in the beater housing, and press the cover correctly into position in the housing.
WARNING — When beating for a high number of revolutions, the temperature of the beating elements may increase. If necessary, cool the beating elements with water to bring the temperature within the specified range before the next beating. The temperature can be measured with an infrared (IR) thermometer or similar.
Set the beater housing in rotation so that the pulp is slung against the wall and start the roll motor. When both beating elements have attained full speed, apply the required beating force per unit bar length. Apply the beating load at a constant rate over a period of 2 s. At the instant of full application of the load, release the revolution-counter lever arm to engage the counter.
When the required number of roll revolutions has been reached, stop the beating by releasing the beating force. Switch off the motors, and allow the roll and beater housing to come to a complete stop. Lift the lid and bring the roll to its starting position.AS NZS 1301.209 pdf download.