Cleaning Protocol for Trap Filters

The purpose of this page is to present guidelines on best practices to affect the efficient cleaning of used fine-grade cartridge filters (for trap filtration) in breweries. These guidelines are intended for general principles only. Because of developments in technology, these procedures may be subject to change. Consequently, we advise users to review their continuing validity with Pall Corporation (Food and Beverage Division)

Cold Water Rinse for Pre-Filter and Final Filter:  Drain entire assembly.-> Adjust the valve position as shown in the picture-> Start the clean water flow ->The rinse water flow rate should be greater than or equal to the process flow rate (1 and 1.5 times the process flow provided the differential pressure does not exceed 300 mbar). Low flow velocity during cleaning may result in insufficient or partial filter cleaning-> Continue in this mode until the effluent appears free of product.

Backwash for Pre-filter Only: Fill housing in reverse direction until water issues from vent-> Adjust the valve position as shown in the picture-> Allow water to flow in the reverse direction to drain at minimum 1.5 times the process flow rate. The differential pressure must not reach above 300 mbar at ambient temperature -> Run ambient water for 10 minutes or until the outlet is clear.

Warm Water Rinse: For forward direction: Adjust the inlet water temperature slowly to 50 ± 5 °C (122 ± 41 °F) and continue to forward flush the filter until the effluent is clear. -> Optional Step: Hold 50 °C (122 °F) water in the housing for 10 minutes to assist in dissolving of soluble contaminants-> When switching from ambient to warm water, this should be done slowly to avoid large and abrupt temperature changes (max ΔT = 40 °C (104 °F)). The same is true for the reverse, cooling. This procedure removes the soluble polysaccharides, sugars, and proteins trapped by the filter. This is an effective regeneration procedure and will help to increase total product throughput. If the filters are not cleaned to remove organic residues, high-temperature exposure during sanitization or sterilization can cause the organic material to irreversibly adhere to the membrane surface and prematurely plug the filter.

Caustic Clean (Weekly or as Required): After warm water rinse ->  Pump caustic solution of 0.5-2% through the filter (housing incl. cartridges) for approx. 10 – 15 minutes-> if caustic soda is dark brown drain it initially then add the fresh caustic solution -> . Now close all valves. The venting valve must remain open. The caustic solution should stay in the filter housing for minimum 30 minutes. Then drain the filter housing.->  Rinse the filter with cold water for minimum of 5 minutes. Then drain the filter housing and neutralize the filter (housing incl. cartridges) with citric acid or phosphoric acid solution of maximum 0.5 % concentration.

Hot Sanitization:  After rinsing with cold and warm water, the filter assembly may be sanitized by increasing the water temperature to 85 °C (185 °F), or the validated sanitization temperature and time as mentioned in Pall filter datasheet.

Cold Sanitization: Cold sanitization can be done by using 150-200 ppm PAA for 30 mins.

Cold Rinse: After sanitization with hot procedure gradually bring down the temperature to ambient. If cold process directly flush with DAW or CO₂ prior to take any production.

Integrity Test Final Filter: For final filter to ensure integrity of the installed filter, it is essential to integrity test the filter before filtration.

For further information please write to foodandbeverage@pall.com or contact your regional Pall representative.