The Disc Filter

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Disc Filter

 

Description

The Disc Filters belong to the side feed group and have been around for many years. They are generally used in heavy duty applications such as the dewatering of iron ore taconite, hematite, coal, aluminum hydrate, copper concentrate, pyrite flotation concentrates and other beneficiation processes. The high time for Disc Filters was in the 60's when the metallurgical industries were booming and filters with 300 m2 and larger were manufactured.

Discharging cake

The filter consists of several discs, up to 15 in the larger machines, each made up from sectors which are clamped together to form the disc. The sectors are ribbed towards the neck and designed for a high capacity drainage rate. One of the main features is that the required floor space taken up by disc filters is minimal and the cost per m2 of filtration area is the lowest when compared to other vacuum filters.

During operation each sector enters submergence and a cake is formed on the face of the discs. It then emerges to the drying zone, the liquid drains to a central barrel and from there through a valve to the vacuum receiver. The valve with its bridge setting controls the timing so that once the sector leaves the drying zone it moves over a separating bridge and a snap or low pressure blow is applied to discharge the cake. Scraper blades on the side of each disc guide the cake to discharge chutes which are positioned between adjacent discs and are wide enough to avoid their clogging by the falling cake. A paddle type agitator located at the bottom of the tank maintains the slurry in suspension which in most of the metallurgical applications contains solids with high specific gravity which are fast settling and abrasive.

 

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Feed Manifold
Overflow Box
Disc Sectors
Barrel and Valve
Swing Blades
Cake Snap Blow
Discharge Chute
Agitator
Tank
Slurry Drain
 

 

 

The filter consists of the following subassemblies:




Selection Criteria

The main considerations in selecting a Disc Filter are:



Operational Sequence

The operation sequence of a Disc Filter is, except for washing, similar to a Drum Filter.

Let us follow a sector as it passes from zone to zone:



Maintenance

Disc Filters are subjected to high wear due to the presence of abrasive solids in the various process slurries. Attention should be given to the following subassemblies: