Peterson’s drum pre-coat filters are specifically designed for pre-coating the drum with a bed of filter aid, usually diatomaceous earth (D.E.) or perlite, which is then shaved off with a scraper blade in very thin layers during a batch run of pre-filter slurry. These filters differ from other rotary vacuum drum filters in the fact that they are used to polish the filtrate that may contain traces of insoluble contaminations.

During the filtration process, the pre-coat filter works as an element to collect much finer contaminants than other vacuum drum filters. By continuously shaving the filter media, a clean filtering surface is presented to the pre-filter feed on each revolution of the drum. This prevents the filter media from blinding and ensures maximum filtration performance. These pre-coat rotary vacuum drum filters are generally used in clarifying operations where very clean filtrate is the desired product.

This specialized operation includes a two stage process: the pre-coating stage and the polishing stage. These two stages are closely related, however, the pre-coating stage determines which filter aid will clean the filtrate during the polishing stage.

Drum Pre-Coat Filters are generally used in the following cases:

• Solutions that require a very high degree of clarity, processing or purification
• When the solid content is low (less than 2-3%)
• When solids are sticky and may clog the filter cloth

For more detailed specifications or information on our pre-coat rotary vacuum drum filters, feel free to contact us at 801-487-7761. We are more than happy to help you come up with the perfect solution for your liquid-solid separation needs.