AS 1301.014:2019 pdf free

AS 1301.014:2019 pdf free.Methods of test for pulp and paper
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.
Collect a representative wood chip sample. This may present considerable difficulty. The sampling plan needs to be one which is appropriate to the circumstances. In particular, experience has shown that taking samples directly from a chip pile can lead to considerable errors. For this method it is recommended that regular samples be taken from the input to the pile or from the outlet stream moving to the next processing stage. AS/NZS 1301.013rp describes the procedure for sampling of wood chips.Protect the chips from gaining or losing moisture.
The test sample size for each fractionation will depend on the dimensions of the screens. Prior to the commencement of screening, the chips should completely cover the top screen to a depth of approximately 40 mm. For example, if the screen area is approximately 0.25 m2, then a 10 L sample would be suitable. If the sample has to be subdivided to obtain a test sample of the required size, take precautions to avoid any fractionation of the material.AS 1301.014 pdf free download.