About the 6221 3731 00 air-oil separator

The 6221 3731 00 is Kenrax's direct replacement air-oil separator for Atlas Copco and CPT compressor service. Atlas Copco rotaries are high-speed and clearance-sensitive, so intake contamination accelerates wear faster than on slower machines. Rather than a generic 'fits most' element, it is built to the specific performance envelope of the machine it replaces.

The 6221373100 air oil separator is a filtration system for Atlas Copco and various other compressors. It removes oil particles from compressed air, ensuring clean and reliable air. With a durable construction and efficient filtering element, it is easy to install and maintain for various industrial applications.

What the 6221 3731 00 does in your Atlas Copco and CPT compressor

The air-oil separator sits between the air end and the point of use. Compressed air leaves the rotors carrying a fine oil mist; the separator's coalescing media collects those droplets and returns the oil to the sump while letting the air pass. When the separator ages, coalescing efficiency decays: residual oil carryover climbs, oil consumption rises, and downstream equipment — dryers, filters, valves, tools, and the product itself — starts to collect the oil the separator should have recovered.

The 6221 3731 00 is a scheduled-service consumable, not a repair item. Fitted as part of the Atlas Copco and CPT machine's standard maintenance, it keeps the Atlas Copco and CPT compressor inside its design operating band between services.

When to replace this element

• Typical OEM interval: 2000–4000 operating hours, or per the machine manual.

• Quality-sensitive plants (food, pharma, electronics) should align replacement with the air-quality audit calendar.

• If separator pressure drop climbs, replace early regardless of hours.

Signs it needs replacement

Replace on any of the above regardless of hour count. For this part, keeping a fresh element in stock before the interval arrives is the single cheapest insurance policy on the machine.

• Oil consumption rising between services with no other explanation.
• Oil film in the receiver drain, piping, or downstream filter elements.
• A rising differential pressure across the separator on the controller.
• The machine running hotter as the separator adds restriction to the discharge path.

Confirming fitment for Atlas Copco and CPT

Fitment for the 6221 3731 00 is confirmed against the OEM part number from your current element. WhatsApp us the number (or a photo of the element) and we verify media grade, dimensions, and sealing before dispatch. Cross-reference is available for Atlas Copco, Ingersoll Rand, Elgi, Kaeser, Chicago Pneumatic, Kirloskar, Gardner Denver, and Sullair machines.

Fitting and verification

• Confirm the element matches the OEM number, dimensions, and sealing arrangement of your old one.

• Check the scavenge/return line and orifice are clear — a blocked scavenge imitates a failing separator.

• Seat the element and torque the housing cover to spec; a poor seal defeats the new element.

• After fitting, verify oil carryover visually and the separator pressure drop reading on restart.

Ordering the 6221 3731 00

Order the 6221 3731 00 directly from Kenrax on WhatsApp or from the product page; assume part-number confirmation takes minutes, not days.