Why Prefiltration is Key in Continuous Filtration Processes.

For many customers, final cartridge filter, either membrane or depth cartridge filter, life must be measured in weeks or months rather than hours or days in multiple process industry applications, especially when the food and beverage, water treatment or industrial (chemicals, digital ink, plating, parts washing) sectors transport liquids.

The only way to ensure an extended continuous operation is to provide the final cartridge filter with high protection from particulate contamination. Therefore, for prolonged, ongoing use, selecting the correct prefiltration is vital to ensure the optimum running costs of a system and the lowest lifetime cost of filtration.

Clients install final cartridge filters to guarantee the quality, so the filters are typically expected to have an extremely low particulate/bacteria challenge level. However, when challenged with too high a contamination level, the filters will quickly block, causing exorbitant running costs for the customer due to repeated replacement.

Therefore, we use prefiltration with depth or pleated depth filters to increase the last cartridge filter life significantly. These filters offer far higher dirt-holding capacity for particulate contamination and protect the final cartridge filter, giving long continuous service life and low filtration running costs.

As a rule of thumb, the final cartridge filter life should be at least two to three times that of the prefiltration filter life and, in the very best cases, can be four to five times. The opposite diagram shows prefiltration’s impact on annual filtration costs.

There are several potential arrangement options for prefiltration. The first is simply to have a single prefilter before the final cartridge filter. Second, for more complex filtration applications, you would use multi-stage prefilters to provide the optimum life of the final filter. Finally, you can use an integrated hybrid prefilter where you add a prefiltration layer inside the last cartridge filter.

The best option depends on particulate and contamination profile, fluid compatibility, flow rate needs, and process removal requirements. Ultimately, you must also consider the available capital budget. Sometimes a customer cannot afford the optimum system cost but trades that against far higher annual and lifetime filtration running costs.

When installing the appropriate prefiltration, one of the most important factors to consider is the void volume of the prefiltration media. Higher percentage of void volume prefiltration media always have a better service life. For example, moving from a prefiltration media with a voids volume of 75% to one of 85% doubles prefiltration filter life and halves these running costs.

Porefiltration supplies a wide range of filter materials and configurations, allowing optimisation of your filtration process and the application knowledge to minimise your filtration costs. We always strive to make your filtration systems work harder.

PoreFiltration – Making your filtration systems work harder