A “one size fits all” approach for chemical air filtration entails a productivity and safety risk in commercial environments reliant on pure air quality. Trying to use one type of chemical air filter for every scenario may provide protection, but without optimization the protection is both limited and temporary.
Understanding the hazards in your environment and implementing the appropriate solution is the foundation of the Entegris “See it. Control it.” model. This is where we “see” the contamination by measuring it accurately and then “control” it by using a filter solution tailored to that specific environment.
Creating Unique Air Filtration Solutions
Air filtration solutions should be unique to each environment and may vary with environmental conditions inside and outside the facility. Filter selection should be based on known contaminants, and optimized media should be selected to maximize the filter lifetime. Off-the-shelf filters rarely meet these needs.
Consider the “inkjet cartridge effect,” referring to old-style inkjet cartridges that held three equal amounts of magenta, yellow and cyan inks. Under typical usage, cyan would run out first, forcing the user to discard a significant amount of yellow and magenta inks when replacing the cartridge. Applying the Entegris approach to this, we would determine first how much cyan, magenta, and yellow is typically used up in a given amount of time, and then adjust the ink amounts accordingly, such that all three are used up at about the same time (Figure 1).
Figure 1: The inkjet cartridge effect for AMC filters visualized. The bars indicate filter lifetime in months for the respective contaminant classes (example: acids, bases, organics), the relative adsorbent (“ink”) amounts are indicated as numbers above each bar. Equal adsorbent amounts yield different lifetimes. Equal lifetime is achieved by using different adsorbent amounts.
Removing Acidic, Basic, and Organic Contaminants
For real-world airborne molecular contamination (AMC) filter scenarios, commercial environments typically attempt to remove acidic, basic, and organic contaminants from air streams. Each of those classes has their own adsorbent for optimized removal but each also has different concentrations in any environment.
The most common and economical filter type for these applications is the combined adsorbent filter, which contains a mix of all adsorbents in one set of (usually pleated or V-bank formed) media. Adjusting adsorbent amounts for an equalized lifetime of all contaminant classes is achievable if the measurements are available. However, each contaminant class may also have different priorities or importance for the application and in some cases, lifetimes may become secondary to the priority of removing one contaminant class more efficiently.
A prerequisite for this approach is an effective analysis of the environment, and both identifying contaminants and their concentration, often in the parts per trillion range (ppt, 10-12), a task that can only be done with a specialized laboratory service. Qualitative methods such as corrosion strips or micro balances cannot provide such results.
These analytical results then have to be put into context of the given application to be protected. An understanding of the application needs, consultation with the facility owner and continuous support throughout the filter life cycle are all standard practices of Entegris’ “See It. Control It” model.
To learn more about AMC solutions, visit our AMC Filters and Analytical Services pages.
