Where should activated carbon filters be located in an instrument air system?

Activated carbon filters are utilized in an instrument air system primarily for the purpose of removing contaminants such as water vapor, hydrocarbons, and other volatile organic compounds from the air supply. Placing the activated carbon filters upstream of the final line filters ensures that the air entering the final filters has already been pre-treated to remove these impurities. This pre-treatment is essential because final line filters are typically designed to catch smaller particles and aerosol contaminants, but they might not effectively remove all chemical contaminants present in the air.

Locating the activated carbon filters upstream ensures that any harmful substances are captured before they can travel downstream into sensitive components or instrumentation that require high-purity air. This placement also helps in extending the life and effectiveness of the final line filters by preventing their premature saturation with contaminants that the carbon filter can more effectively adsorb.

Therefore, the correct positioning of activated carbon filters upstream of the final line filters is crucial for maintaining the integrity of the entire air delivery system and ensuring optimal performance of the instrumentation relying on instrument air.