AS 1301.014:2019 pdf free download.Methods of test for pulp and paper Method 014: Size classification of wood chips.
4 Principle
A sample of chips is taken from a lot and classified into different fractions using a chip classifier. The
weight of each fraction is reported.
5 Apparatus
5.1 Chip classifier
The chip classifier shall be comprised of several screens and a fines pan mounted above each other in a shaking frame in such a way that there is no loss of chips or fines during screening.
5.1.1 ShakIng frame
The shaking frame may function in a reciprocating motion (side-to-side) or circular vibrating motion. The frame shall have a mechanism for shaking the screens continuously and vigorously so that screening is completed within the time specified in the procedure.
5.1.2 Screens
Screens with holes separate the chips according to length. Screens with slots separate the chips according to thickness. The number of screens in the stack and the dimensions of the screen apertures determine the distribution of the chips between the fractions. Some preferred screen combinations are given below. These are guidelines only, and other configurations and screen apertures are acceptable. Where the apertures are circular, all holes need to be complete circles. Part holes, i.e. at the edges of the screen, are not allowed. If the diameter of the hole is 6.5 mm or less, permissible variation in diameter is 5 %. If the diameter of the hole is greater than 6.5 mm, permissible variation in diameter is 3 %. The holes shall be placed in a pattern of equilateral triangles, and the distance between the centres of adjacent holes shall be the diameter of the hole plus at least 20 %.
Screens with slots are generally made up of two rows of parallel rods of diameter 5 mm or 6 mm as illustrated in Figure 2. The slot dimension is the distance between two adjacent rods in different rows. Permissible variation in the slot dimension is 5 %. The slot dimension corresponds to the maximum chip thickness which can pass through the screen.AS 1301.014 pdf download.