Hall Pyke have been providing filter integrity testing services for many years now and the team have seen filters come into the laboratory in various conditions. In this blog we delve into how a filter can fail a filter integrity test due to a lack of understanding about the dynamics of vent filtration.

The dynamics of vent filtration

The team at Hall Pyke received filters back for filter integrity testing and upon initial examination it was noticeably clear that the filters would not pass any filter integrity test. Picture 1 and 2 below show the condition of the filters when the team at Hall Pyke received them.

Filter exposure to extreme heat

In this case, the filters were used as sterile vents on a hot water process tank. It was clear from initial examination that the process itself did not cause damage to the filter. As seen in the images above, the hardware, outer / inner cage, and end caps had melted due to extreme heat. The hardware of the filter was made from polypropylene, a material that has a melting point of 160 degrees Celsius.

The team decided to test a similar filter in the lab oven for 10 minutes at 250 degrees Celsius and the outcome can be seen in picture 3 below. From this test, it was clear that the temperature was between 160 and 250 degrees Celsius.

What can cause a filter failure like this?

A heating jacket failure could cause a filter failure like the example we have discussed above. The controller could have failed, causing the jacket to rise above the 160-degree Celsius limit of the filter hardware.

The positioning of the filter housing is also a possible cause of such a filter failure. In vent applications the housing must always be positioned in the vertical. On hot water tanks, steam vapour can pool in a filter housing that is positioned on the horizontal. This can cause failure of the jacket controller as it struggles to maintain the temperature. Failure of the controller can then result in the jacket overheating the filter housing.

Understanding the dynamics of vent filtration can avoid issues like filter failures from occurring. For more information about vent filtration dynamics, get in contact with the team at Hall Pyke today on +353 1 4501411 or email us at info@hallpyke.ie.