Air Dryers & Main Line Filters
Air dryers and main line filters are the air preparation equipment that removes moisture, oil, and particulate from compressed air before it reaches your pneumatic valves, cylinders, and instruments. Contaminated air shortens component life, fouls heat exchangers, spoils paint and coating finishes, and drives unplanned downtime. Automation Distribution stocks SMC air dryers, main line filters, water separators, mist separators, aftercoolers, and auto drain valves to help you build clean, dry, ISO 8573-1 compliant compressed air at the point it enters your system.
Which air treatment product do I need?
Compressed air treatment works in stages. Each SMC series targets a specific contaminant and a specific cleanliness class, so most systems combine several components in sequence:
- Aftercoolers — installed directly after the compressor to drop discharge air temperature to roughly 40°C or less, condensing the bulk of the water vapor so downstream equipment sees a lighter moisture load.
- Water Separators (SMC AMG Series) — mechanically remove bulk liquid water droplets from the air line, with a water removal ratio of 99%. Used as a first line of defense ahead of filters and dryers.
- Main Line Filters (SMC AFF Series) — coalescing filters with a nominal 3 µm rating that remove oil and solid foreign matter. SMC recommends the AFF series as a pre-filter ahead of a refrigerated dryer to prevent fouling of the dryer's heat exchanger. The AFF-D variant uses a thinner stainless steel bowl.
- Mist Separators (SMC AM Series) — coalescing filtration to a nominal 0.3 µm rating, reducing oil carryover to roughly 1 mg/m³ (ISO 8573-1 Class 3 oil).
- Micro Mist Separators (SMC AMD Series) — secondary-stage coalescing filtration to 0.01 µm, reducing oil carryover to roughly 0.1 mg/m³ (ISO 8573-1 Class 2 oil).
- Micro Mist Separators with Pre-filter (SMC AMH Series) — a high precision separator that integrates a 0.3 µm pre-filter and 0.01 µm element in one space-saving body, removing aerosol oil mist plus carbon and dust. Suited to air micrometers, measurement instruments, and precision parts cleaning.
- Odor Removal Filters (SMC AMF Series) — activated carbon filters that adsorb oil vapor and odor when higher air quality is required.
- Membrane Air Dryers (SMC IDG Series) — compact, power-free dryers that lower the pressure dew point without refrigerant or desiccant. The IDGA variant adds an integrated pre-filter. Ideal for localized, point-of-use drying.
- Auto Drain Valves — automatically discharge collected condensate from filter and separator bowls, eliminating manual draining and preventing re-entrained water from reaching downstream equipment.
Refrigerated, membrane, or desiccant drying?
The right dryer depends on your required pressure dew point and ISO 8573-1 air quality class. For most general industrial applications — powering pneumatic tools, cylinders, and valves — air filtered to ISO Class 4–6 is adequate. Applications demanding ultra-dry air, such as instrumentation, clean rooms, food, or pharmaceutical processes, or air lines exposed to near-freezing temperatures, call for lower dew points and tighter filtration. SMC air preparation equipment can reach dew points as low as -60°C and flow ranges up to 1,000 L/min, with coalescing filtration down to 0.01 microns. If you are not sure which combination fits your line, the team at Automation Distribution can help you size it.
Why buy SMC air preparation equipment from Automation Distribution
Automation Distribution is an authorized SMC distributor. Browse the full range of SMC aftercoolers, air dryers, water separators, main line filters, mist separators, and auto drain valves below, or contact our team for application support, sizing, and replacement element cross-referencing.