The Grinding Fineness Tester SR 1 is used for the determination of the dewatering rate of pulp and ground wood materials.
The apparatus permits the reliable determination of how quickly the pulp on the screen drains and makes it possible to assess the fineness of the material because the dewatering rate and the degree of grinding of the fibre material are closely related.
There are numerical values for the otherwise relative terms “crisp” and “smeary” dependent on the personal opinion of the observer. The tests can be undertaken so quickly that it is possible to track continuously the effect of a beater or other grinders on the fibre material.
The test method
Consists of the dewatering of 2 g of notionally dry material finely distributed in 1000 cm³ water through a screen. The screen forms the base of a chamber that is placed on a funnel with two outlet openings at different heights.
If the material dewaters quickly, which characterises its crisp state, a large portion of the water flows through the higher opening, with smeary materials only a small amount. The quantity of water under the outlet on the side is a measure of the dewatering rate and the grinding fineness of the material. A scale is applied to the measurement vessel where a reading can be taken directly.
A funnel-shaped separating chamber with two outlet openings is positioned in a stand. A filling chamber is arranged in the separating chamber; in this chamber there is a screen with a specific mesh size and area. In the filling chamber there is a sealing cone that seals the filling chamber in relation to the separating chamber so that the material-water mixture can be added before the test.
The sealing cone is removed from the filling chamber by the force from a falling weight. For this purpose a toothed rack is attached to the cone; the toothed rack engages in a gearwheel. The gearwheel is connected to a roller over which a cord is placed; a weight is suspended on the end of the cord. After releasing a catch the cone is raised at constant velocity.
- Dimensions: 450 x 250 x 1000 mm (length/width/height)
- Weight: net 34 kg, gross 86 kg
- Installation: The device is placed on a bench and aligned using adjusting screws