SMC AFF Main Line Filters

SMC AFF Series main line filters are the first stage of filtration in a compressed air purification system. Mounted directly on the main air line, an AFF filter removes bulk foreign matter, water droplets, and oil — protecting downstream dryers from fouling and extending the service life of the finer, more expensive coalescing filters behind it. Automation Distribution stocks the full SMC AFF and AFF-D range across body sizes and port configurations.

What does an AFF main line filter do?

The AFF series is designed as the coarse, high-capacity front end of an air treatment train. It catches the contaminants that would otherwise overload precision filters and foul heat exchangers: SMC specifically recommends an AFF filter as a pre-filter ahead of a refrigerated dryer to avoid fouling the dryer's heat exchanger. AFF filters mount to main piping without screw threads or tie rods, so element removal and replacement is quick — a dirty element can be disposed of while handling only the filter bowl. Putting an AFF up front improves downstream dryer performance, extends precision filter life, and helps prevent moisture- and contamination-related equipment failures.

Legacy AFF vs. AFF-D vs. AFF70~90D

SMC's AFF range spans the original series and two updated generations. The right one depends on the filtration rating you need, your port size, and whether you want integrated water removal:

  • Legacy AFF Series — a coarse 3 µm filter that removes foreign matter and droplets as an excellent first stage in an air purification scheme. Proven, widely specified, and easily serviced.
  • AFF*-D Series — a modular update nominally rated at 1 µm, designed for modular connectability and to match the aesthetics of SMC's AC-D series FRL components. Flow capabilities are improved over the legacy AFF for broader applicability.
  • AFF70~90D Series — large-capacity filters that improve on the legacy AFF with a 1 µm particulate rating and water removal, integrating the traditional AFF filtering function with the water-separation capability of the AMG series in a single unit. Reduced installation space, improved flow capacity, and a lightweight stainless steel bowl assembly that simplifies handling and service.

The AFF2C-22C grouping covers a specific body-size and port configuration within the AFF range — useful when you're matching an existing installation.

Where AFF fits in the air treatment train

AFF filtration is the coarse first stage — it comes after an aftercooler and ahead of finer coalescing stages. For oil-aerosol removal at 0.3 µm and 0.01 µm, pair the AFF with SMC AM mist separators and AMD micro mist separators; for bulk liquid water, see AMG water separators. Browse the full air dryers and main line filters category to build the complete treatment train, and add an air dryer to bring the air to its required pressure dew point.

Buy SMC AFF main line filters from Automation Distribution

Automation Distribution is an authorized SMC distributor. Browse the SMC AFF and AFF-D main line filters below, or contact our team for help selecting a filter by port size, flow rate, filtration rating, and drain type, or for matching replacement elements to an existing AFF installation.