HEPA, ULPA, PTFE Non Standard Air Distribution Screens
At times customers have asked for HEPA/ULPA/PTFE filters that re not either square or rectangular. These odd shaped filters have been attempted by various filter vendors, without much success, as the filters are hard to consistently seal. At present no “A” list HEPA/ULPA/PTFE manufacturer will agree to build a filter that does not have 4 ea equal 90 degree angle corners, meaning all filters can only be square or rectangular.
So, how to we address the issue when the clean zone has a triangular corner, or is just larger than the HEPA/ULPA/PTFE filter?
The answer? Add to the design an air distribution screen, which introduces a secondary pressure plenum that forces the filtered air to “spread out” uniformly to match the shape and size of the final clean zone.
The following PDF presentations will allow you to see how they work conceptually, how they are constructed, and some test results using the screens with varying secondary plenum depths and different screen material combinations.
Check them out and feel free to call me for more information.
- Air Distribution Membranes – The Concept
- Air Distribution Membranes – A Study – Various plenum depths with both 2300 and 2500 screen materials
- Air Distribution Membrane – Design Considerations – Available screen materials, and frame design