What is a filter integrity test?
Filter integrity tests are conducted to verify and ensure that a filter membrane meets quality and regulatory requirements. If a filter fails the integrity test, it indicates that the filter is no longer reusable and that previously filtered batches may need inspection.
How does a filter integrity tester work?
Filter integrity testing can be categorized into two types: Destructive and Non-Destructive testing. Non-Destructive tests include the Bubble Point, Diffusion, and Pressure Decay tests, which are chosen based on specific testing requirements.
What is the bubble point test for filters?
The bubble point test operates on the principles of capillary action and surface tension. When liquid passes through the filter, it fills the pores due to these forces. Pressure is then applied to displace the liquid from the pores, allowing for pore size measurement. The minimum pressure required to push the liquid out from the smallest pore determines the bubble point, which indicates the pore size.
What is the water intrusion test?
This test is commonly used to detect defects in hydrophobic filters, typically used as air vent filters. In this test, water is pressurized into the upstream side of the filter to assess filter quality, comparing results to the manufacturer's specifications.
What does bubble point mean?
The bubble point is the minimum pressure at which the first bubble of liquid emerges from a pore in the membrane. This pressure value helps characterize the pore size and quality of the filter.