Rotary Drum Vacuum Filter

Description

How a Rotary Drum Vacuum Filter Works:

Drum Rotation:

The rotary drum is a large cylindrical drum that rotates slowly, typically in a horizontal or slightly inclined position. The drum is partially submerged in the slurry or liquid mixture (usually contained in a trough or vat).

Vacuum Filtration:

As the drum rotates, a vacuum is applied on the inside of the drum, which pulls the liquid (filtrate) through the filter medium (usually a cloth or mesh). The filter medium is attached to the drum’s surface.

The slurry (a mixture of solid particles and liquid) flows onto the surface of the drum, and the vacuum draws the liquid through the filter media, leaving the solid particles to form a filter cake on the drum’s surface.

Cake Formation:

As the drum rotates, the solids accumulate on the surface, creating a filter cake. This cake increases in thickness as the drum continues to rotate and filter more slurry.

Cake Discharge:

As the drum completes its rotation, the filter cake is typically removed by scraping or brushing. Mechanical arms or knives are often used to scrape off the cake and discharge it into a collection bin or conveyor for further processing or disposal.

Washing and Dewatering (Optional):

Some rotary drum vacuum filters are equipped with a washing system, where liquid (typically water or another solvent) is sprayed onto the cake to wash away soluble impurities. This helps to purify the cake, removing any residual liquid or unwanted substances from the solid particles.

Filtrate Collection:

The liquid that passes through the filter is called the filtrate, and it is collected in a trough beneath the drum. The filtrate can then be discharged for further treatment or use in the process.