All filters cleaned by PPSL are fully tested and the results compared with the “as new” technical specification published by the filter manufacturer. The following tests regimes are undertaken as standard:
Bubble Point Testing: The cleaned filter is submersed in alcohol and plugged. Air pressure through the filter is increased gradually and the back pressure is recorded at the point when the first bubble appears through the media. Essentially this test provides an indication of the largest pore size of the filter that can then be compared to the manufacturers specification.
Flow Testing: After the ‘Bubble Point’ is established the back pressure is the recorded at a air flow rate of 10LPM. This gives an indication of the mean pore size of the filter and can be used to assess the integrity and performance the filter will give online. PPSL can also extend the flow test with a visual check using our technical expertise to provide additional performance indications and filter integrity beyond data point generation.
Weight Check: All filters are weighed after cleaning. This enables us to compare the weight of the cleaned filter with the base weight of the new filter. Over time, weight loss can be tracked, and can be a useful factor when determining the continued integrity of the filter.
Visual Inspection: All filters are carefully checked, both on receipt and after cleaning, the signs deterioration of the media, physical damage or anything else out of the ordinary. Where damage or imperfections are found that could impair filter performance we will advise the customer. If we believe that the damage can be repaired we will advise on the likely cost of repair and if requested arrange for the repair work to be undertaken.