Pulp Drum Washers
Pulp Drum Washers
Pulp Drum Washer is the equipment used to wash the cooked pulp or to bleach pulp while separating the residual liquor / Bleaching chemicals. Washers are commonly used in every Pulp & Paper Industries.
Vacuum Drum Washer Working Principle
The vacuum drum washer can either be used alone or in series group. The main components of a vacuum drum washer include a Rotary Drum, Tank/Vat, Auto Valve, Washing showers, Scrapper, Drive Gearbox with accessories like screw repulper conveyor for transportation of pulp to storage towers.
Working Principle & Application
Drum surface of the washer drum is divided into several segments / compartments. Segments are covered with Deck Panels and the entire drum is covered with Filter cloth or Wire mesh. Each segment is connected to the Auto valve seat through the filtrate pipe. Auto valve core divides the end face into different zones mainly, Vacuum, Washing, Drying and Pulp Discharge Zone. As the drum rotates in the tank containing the pulp, and each segment of drum passes through these zones. Autovalve is connected with straight pipeline (also called as barometric leg) downward to the Seal pit. As the liquor passes through barometric leg vacuum is generated in drum internal piping thus lifting the pulp from the vat and separating the liquor. Drum rotates and thus, continuously separates out pulp and liquor at every rotation.
Scrapper or discharge assembly removes the pulp mat and is being sent to Pulp stock towers by means of Conveyor Repulpers. Pulp Drum Washers can be used in series for Brown Stock as well as for Bleach Washing. Material of Construction for Pulp Drum Washers and its accessories may vary depending on their application.
Normally, Drum Filters in Brown Stock Washing section are in Carbon Steel / SS304 and in Bleaching section MOC may be SS316L, 317L, 904L, SS316Ti, etc. depending on application.