| 摘要 |
Device and measuring method based on volume using which the particle size distribution and bark content can be determined for wood chips which are used as the raw material in the cellulose and paper industry. The hand-operated, light portable device which replaces stationary and heavy electrically operated laboratory screens and scales and heating chambers comprises a measuring vessel of 10 litres 1 for the original sample, a framework container 2 for the screens, a bottom container 3, removable screens 5-9 which form the bottom of the framework container and fixing rods 4a, 4b for holding the screens. For measuring the fractions obtained by manual screening there are measuring containers 10-15 provided with percentage scales. For recording the result a pre-completed report sheet 16 has the outline of a bar chart on which the percentage result of the fractions is recorded. When the quantities of only certain determined fractions are to be checked, separate measuring containers 10 and 11 are used for the large fractions and there is a separate calibrated measuring container for the combined fine fractions 14+15. When processing woodchips for sale, these containers can also be provided with pricing scales. For determining the bark content the device comprises a screen 2, 3 provided with a plate with holes 8. After the removal of the fine material 2 litres of the sample are measured using a measuring container 17 provided by the method and spread out on an even surface 18. The bark particles are picked out into a calibrated bark measuring container 19 provided with a percentage measuring scale. The result is read off from the scale as percentage by weight. For determining the knot content in a sample of woodchips the same method is used as for determining the bark content with the only difference being that the knots are measured using the measuring container for oversized 10 or overthick 11 fractions. <IMAGE>
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