The Canadian Standard Freeness is worldwide used for determination of the drainability of a dilute pulp suspensions of wet section in the paper machine. The rate of drainage is stated in terms of freeness. The freeness of pulp, as well as drainage rate is the measurable index of the effectiveness of refining process because it is connected to the work done on the pulp fiber during beating or refining and swelling of the fibers. This particular experiment is appropriate to all variety of pulps in aqueous suspension but especially for mechanical pulp.
The Canadian Standard Freeness test works based on the principle just like the SR-tester. The dissimilarity is that the pattern of the funnel and the orifices; moreover the wire screen is replaced by a screen Plate. The volume of test samples same like the SR-tester that is 1000 ml, but the consistency is difference, it is three grams per liter rather than two grams. The drainage Water is collected into a measuring glass (which is scaled in ml) through the side orifice outlet and represents as “freeness mI/CSF”. The Canadian Standard Freeness tester scale is marked from 0 to 1000 ml and the working range from 30 to 850 ml. To begin the drainage, unlock a vent valve rather than lifting a tightening cone upwards. A “free” stock dewaters quickly and results in a large volume in the measuring glass, corresponding to a high CSF value.
The properties of the water are different, if the consistency and temperature are change. So it is very important that the test must be performed at a specific consistency and temperature. If it is differs, it is need to be correction to obtained actual CSF value. As like SR-test it is recommended that the sample should be test twice. If the test result differs by more than 4 %, the entire test should be repeated.
In moment absolutely zero, while the total sample is locked in above the screen, the rate of drainage is zero. After the draining process begins, the draining increases to an upper limit after which it decelerates to approach zero. Subsequently all the water in the sample suspensions has exhausted throughout the screen and the fiber pad of The Canadian Standard Freeness tester.
The drainage amount of resistance of the stock is very significant mainly as it delivers information of the paper sheet that could be manufactured from the stock’. The denser the wet fiber pad and therefore the poorer the permeability, the fewer the drainage rate and the lower the freeness.