Aircel DS Oil/Water Separators for Condensate Management

The Aircel DS Oil/Water Separators utilize gravity to separate oil/water mixtures and purify the condensate to a residual oil content of 20 ppm or lower. Designed to meet or exceed those discharge levels as efficiently and economically as possible. The DS Oil/Water Separator is available in seven models ranging from 70 to 4,500 scfm.

The need for condensate management occurs when liquid condensate is generating at several points throughout a compressed air system, including the outlet of the compressors itself, within accumulator tanks, cyclone separators, coalescing filters and refrigerated air dryers. Whenever condensate forms, it must be removed from the compressed air system and discharged in a manner that is both environmentally sound and economical.

The amount of condensate generated within a compressed air system can be surprising. As an example, a 500 scfm system operating in ambient conditions of 60°F and 65% relative humidity can generate nearly 2 gallons of liquid condensate per hour. That condensate, however, will be generated at a number of points within the system. All of this condensate must be removed from the compressed air system. This is accomplished with the use of drain valves.

When oil is present, as with oil lubricated compressors, the condensate must be purified to legal levels of residual oil content before it can be discharged to public water treatment systems. Typically, condensate will contain on the order of 5% oil. That level must be reduced to 20 ppm or lower, depending on local ordinances.

DS oil/water separators utilizes gravity to separate oil/water mixtures and purify the condensate to a residual oil content of 20 ppm or lower. Designed to effectively and efficiently separate oil from compressed air condensate this unit is available in 7 models ranging from 70 to 4,500 cfm. The DS Series are easy to install, operate and maintain. They require no power, unless fitted with an optional heater, and operate without intervention between maintenance intervals.

  1. Liquid condensate and compressed air enter the pressure relief chamber at the top of the unit.
  2. A foam coalescing pad captures condensate droplets that are entrained in the expanding and exhausted air stream, which exits the top of the unit.
  3. Liquid condensate enters a removable pre-sedimentation chamber where solid particles are separated and captured.
  4. Condensate exits the pre-sedimentation cham­ber by passing through a coalescing foam block which begins the process of oil-water separation.
  5. Condensate flows into and fills the primary set­tling chamber where gravity separation of liquid oil and water takes place.
  6. Separated oil is skimmed from the surface of the settling chamber through an adjustable oil drain tray.
  7. Oil is captured in a removable container and held for proper disposal.
  8. Separated water is drawn from the bottom of the settling chamber for final purification.
  9. Separated water flows downward through a pre-adsorber that captures additional oil and pro­tects the carbon bag(s) that follow.
  10. Activated carbon removes oil to a residual level of 20 ppm or lower. Depending on the size of the unit, one or two carbon adsorption chambers will be present.
  11. (11a)Purified water is drawn from the bottom of the carbon adsorption chamber and then either exits the unit (11b.) or passes into the second carbon adsorption chamber if present.

How it WorksOi-Water_Sep

Thermostat Controlled Heater

If the DS Oil/Water Separator is installed in an area where the ambient temperature might go below 34°F, use the optional thermostat controlled heating unit to prevent freezing of the condensate.

Condensate Distribution Manifolds

Often more than one separator will be required to meet the needs of a given operation. In those instances, distribution manifolds are available to assure that condensate is evenly distributed among the connected oil/water separators.


  • Only for compressed air condensate.
  • Donaldson guarantees a residual oil content of less than 20 ppm in accordance to EN ISO 9377-2 with DS Oil/Water Separators.
  • The warranty only applies to:
    • Proper use with an oil/water mixture from air compressor condensate
    • Use of original replacement and spare parts.
    • Proper installation and commissioning according to the manual.