Scientific Journal of KubSAU

The article deals with the issues connected with pulpwood barking and chipping in chippers and wood chip screening according to its size. The authors consider structural and technological factors influencing the quality of the product and determine the tasks for future research of chip production operations at pulp and paper mills. The review and the comparative analysis of the most common equipment used for chip production at pulp and paper mills in Russia are submitted

The article proposes the updated model of the influence of logs length onto a size of wooden chips produced with the use of a disk chipper. This article focuses on the fact that the length of any of the logs in the process of chipping is reduced. For this reason at the final stage of chipping, any of the logs with a standard initial length of 1.2 m inevitably transform into short logs, for which the conditions of chipping are significantly different from the chipping conditions at the start of chipping. The task of accounting for these changes is reduced to finding a solution of the transcendental equation. The results of numerical simulation indicate a progressing decreasing trend in the bevel angle and increasing in the length of the particles of wood chips with decreasing of logs length. Adequacy of the modeling results confirmed by laboratory tests and production experiment. Measuring linear and angular dimensions of chip real particles showed that the particles of such length may be equal to 7 cm, which is 3.5 times larger than the standard length of 2 cm. The angle of the bevel of the cutting plane of the particle may be 14º, which is approximately three times less of standard value equal 39º- 43º. We also discuss the comparison with the approximate solution, which was published in 2012 year. The article can be useful for specialists of wood-preparatory cycle in the paper industry