As feature size continues to shrink, processes that did not originally require the elimination of molecular level contaminants (AMCs) are now finding the addition of an AMC prefilter retrofit kit to be necessary. Since the FFU in the EFEM was not originally designed to handle the additional pressure drop of the AMC filter(s), which in some cases can be as high as 0.85” WG static, an active AMC prefilter is required.
The image below is of a multi element tray style AMC housing. In this design each AMC filter element can be designed to remove a specific species so that AMC removal performance can be optimized. An additional benefit is that the individual elements are changed, only when they are spent, and not requiring all 3 to be changed at once as is the case with multifunctional AMC HEPA fan filters.
In the normal case where the fans in the original FFU need a boost, the AMC chimney adds a fan (circled in red) to handle the pressure drop of the AMC filters. And the entire assembly sits on top of the tool, somewhere above the FFU.
When it is required to add an AMC prefilter to an existing EFEM you will find TES-Clean Air Systems to be the right partner to meet that need. Give us a call at (510) 656-5333 or if you prefer, fill out the contact form by clicking here.