PRIMENA I DIMENZIONISANJE HIDROCIKLONA U PAPIRNOJ INDUSTRIJI

The approach flow is the section of a paper machine between the machine chest and the headbox. It is made up of a number of unit operations in order to clean contaminants, refine, deaerate and dilute (control the consistency) stock before it is distributed uniformly over the width of the machine in the headbox. Well-designed approach flow system supply a continuous suspension flow of constant consistency, quality and flow rate at constant pressure to the headbox of the paper machine. Variations of stock flow rates less than 1% from nominal flow rate are preferable. Hydrocyclones play a crucial role in the approach flow system of a paper machine by improving stock cleanliness before the pulp reaches the headbox. They are a type of centrifugal cleaners which remove unwanted particles from the pulp suspension, such as: sand, grit, metal particles, ink residues, plastics. The principle of filtration is based on the high-velocity tangential flow where the pulp slurry is pumped into the hydrocyclone at high speed tangentially, creating a vortex. Centrifugal separation occurs with heavy particles (rejects) that are pushed to the outer wall and exit through the bottom (reject port). Light, clean fiber suspension (accepts) exits through the top (overflow outlet) and continues toward the headbox. In this paper application of hydrocyclones in the paper industry is analized and methodology for their sizing and selection is presended.