Filtration

Learn What Filter Type and Size Is Best With Filtration Testing

By performing filter tests, we can determine the filterability of a slurry and determine the size of filter needed. These tests can also help decide if you need a horizontal belt filter, drum filter, or some other type of filter. The filtration tests can determine the optimum solids concentration and/or filtrate clarity that can be achieved.

Filtration testing includes filter cloth determination, filter cake solids or moisture determination, filtrate clarity, and cake wash efficiency, when needed. Filtration testing can also determine the best filter type or treatment for a particular slurry.


Vacuum Filtration

Drum filters, horizontal belt filters, disc filters, and other filter types use vacuum pressure to improve the filtration rate and liquid extraction beyond gravity filtration alone. Most filtration testing in the WesTech lab is under vacuum. This allows us to control the vacuum level, compare the performance of different cloths, and determine other parameters needed to size a filter.

Precoat Filtration

The solids in some slurries may be too small and diffuse to form a cake by regular vacuum filtration. In these cases, a bed of material, or precoat, can be built up on the filter cloth to catch the solids and keep them from passing through the filter cloth with the liquid. With each complete cycle, a blade removes a thin portion of the precoat, taking the solids with it and leaving a clean precoat for the next filtration cycle.

Filtration testing

Filter Press

Another driving force used in filtration is compression – forcing the liquid out by squeezing the slurry in some manner. We have a benchtop filter press that uses plates of varying thicknesses to test this type of filtration. With an air compressor providing the driving force, an air diaphragm pump pushes the slurry into a chamber that has filter cloths on both ends. We use the data generated during testing to size a filter press for the specific slurry submitted.