1986 Volume 40 Issue 12 Pages 1159-1167
Principle of separation or classification with hydrocyclone is to make use of difference in settling volocity under centrifugal force among particles. It has been shown that Centri-Cleaner 600 is elective for the separation of vessel elements from wood fibers of various BKPs. This paper deals with experimental study of settling velocity of various pulp fibers, vessel elements and model particles. The results were used to explain mechanism of separation with hydrocyclone.
With the model particles of vessel element, it was comfirmed that particles with large projected area and small L/D ratio (length to width ratio) settled faster in water. And the settling velocity of model vessel element was a function of its apparent density and thickness. The settling velocity of fiber, on the other hand, was proportional only to a diameter and apparent density of fiber.
Effect of pulp consistency on vessel separation was also examined in terms of space available for vessel element to fall through the network of pulp fibers. The extremely low separation efficiency of vessel elements with high L/D ratio could be explained by the space availability.
