Consider the following example of a failed UF element due to low paint flow. Why was there low paint flow? As you can see in the photo, there were many large foreign objects on the inlet face of the UF element as opposed to the photo depicting how a clean inlet face should appear. The low paint flow reduced the flow of permeate and also allowed the gel layer on the face to grow in thickness and hardness.

You can also see a large opening between two adjacent spiral layers in the damaged UF element. The foreign object blocked the normal flow so it forged a new path and caused the gap to open. Paint was detected in the permeate too; the hypothesis being that this relative motion was too much and caused the fragile UF membrane to rip.

Finally, the bag filter hadn’t been emptied on a regular basis which caused the bag to rip and allow unfiltered material to pass directly to the UF elements.

In short, Several UF preventative maintenance activities performed during the year will pay benefits, reduce surprises and lessen down time.