General
When compared to thermal drying, mechanical moisture removal is much more cost-effective. To benefit from this, it is wise to employ mechanical methods, when appropriate, to produce filter cakes with reduced residual moisture content. When this is done, various advantages may result. These include energy savings, debottlenecking of downstream dryers/calciners, cheaper and easier cake transportation, or disposal, and improved acceptability of the cake.
The Dorr-Oliver type press belt drum filter exploits these advantages in a practical way. Essentially a vacuum drum filter fitted with a pressing stage, it continuously transfers the filter cake into a pressing zone. As a result, filter cake moisture may be reduced by 20 % to 50 %. Often the unit will pay for itself within one year.
Overview
The Dorr-Oliver type press belt filter is particularly suited for filtration and dewatering of suspensions and slurries containing the following materials:
- Pigments, fillers and fine particles;
- Compressible, fibrous or porous substances;
- Particles forming cakes with a tendency to crack during filtration, or which exhibit thixotropic behaviour.
The Dorr-Oliver type press belt drum filter sets new standards for significant reducing residual moisture in the filter cake. Due to ingenious filter design, cake emerging from the filtration zone is conveyed continuously into an additional cake pressing zone.