Rotary Vacuum Disc Filter Basics

Rotary Vacuum Disc Filters, also known as Sector Disc Filters, or Save All Filters in paper mills, provide excellent filtration area in the smallest footprint. Several discs stand in front of one another, connected to a center barrel and rotating through slurry, open air, and the discharge zone. Each disc is comprised of sectors, shaped like a slice of pizza. Each sector is either grooved or made of punch plate to allow liquid to pass through a cloth bag, into the sector, and out the center barrel. Both sides of each disc filter slurry simultaneously.

Like the Rotary Vacuum Drum Filter, a Disc Vacuum Filter pulls slurry from a tank under the center barrel of the filter. A solid cake forms on both sides of the disc surface while submerged. As the disc rotates out of the slurry tank, the sector continues pulling vacuum, allowing the cake to dry.

While the slurry tank is on one side of the filter’s base, discharge chutes sit on the other side of the base, capturing dried solids before the sector reenters slurry in this continuous filtration process. To discharge, most disc vacuum filters use a low pressure burst of air to inflate the sector’s cloth bag and make contact with scraper blades on either side of each disc.

Disc Vacuum Filters are ideal if the slurry has a high liquid content and if the solid cake discharges easily.

Rotary Vacuum Disc Filter Components

Valve- The side of the valve facing the vacuum pump has two holes, one for vacuum and the other for blow discharge. The side of the valve facing the filter has bridge blocks with separate sections for cake formation, cake drying, and blow discharge.

Sectors and sector bags- Sectors are made of metal, plastic, fiberglass, or wood. The cloth sector bag captures the solid cake while the liquid passes through the cloth into the sector, through the center barrel, and out the filter valve.

Center Barrel- A connected series of tubes, one for each sector, with a hole for each disc, comprises the center barrel.


Filter Tank and Agitator- The disc filter’s tank holds the slurry awaiting filtration. At its bottom, an agitator revolves, continually mixing the slurry to keep a consistent liquid to solids ratio. Propeller and paddle agitators are common.

Variable Speed Drive- An electric motor powers the variable speed drive, allowing the rotation speed to vary, accommodating for productivity of the specific application. Worm gears and chain drives are commonly used with the drive.

Troubleshooting Rotary Vacuum Disc Filters

Check out this article for tips on troubleshooting a sector disc filter from our liquid filtration equipment specialists. We've been to countless mills and mines to work on this equipment, now we can save you some time getting up and running again.

Industrial Filter Media Identification

National Filter Media has the analytical equipment and expertise to identify fabric. Based on our findings you may choose to replace with the same filter media or upgrade to improve performance, reduce down time, or cut costs. Click the link to learn more.

Rotary Vacuum Disc Filter in Mine Runs Longest on Duralast

Is your Sector Disc Filter operating in a highly abrasive slurry? Check out this article to reduce change-outs.

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