Donaldson's versatile WSOFlex collector provide a more productive work environment by reducing coolant and machining oil mists in a compact package. The WSOFlex can be modified with a simple filter change, leading to leaner operation, cost savings and cleaner plant air.

WSOFlex Offers:

  • 3 in 1 solutions for water-soluble, straight oil, and oily smoke applications
  • Choice of coalescent filter media technology (Dryflo® or Synteq XP™) to match your filtration needs
  • High performance optional 3 stage filtration to efficiently cover specific applications
  • Cross-flow design for better drainage and extended filter life
  • A cleaner work environment for maximum productivity
  • Zero-leak design helps reduce risk of mist-related hazards
  • Quick and easy filter changes - workers have minimal contact with collected oil
  • Predictable maintenance with programmable ΔP alerts
  • Option for machine mounting and floor stands

The WSOFlex is specifically engineered for the demands of your wet machining applications. Up to three filtration stages work together to clean the air with a focus on maximum efficiency and a low maintenance cost:

Stage 1: Contaminated air passes through prefilter

Stage 1

Contaminated air enters the WSOFlex mist collector through the dirty air inlet, located at the bottom of the unit. 

The air then passes through the prefilter, which is designed to collect and coalesce large droplets and particles. Depending on the application, a different first stage prefilter can be selected.

  • Metal wire mesh for most water-soluble mist
  • Thin metal screen for heavy particle loading applications
  • Polypropylene mesh for heavy liquid loading applications

Stage 2

At this point, the air still contains small mist droplets. The filter element is the heart of the mist collector, as it ensures that only clean air is returned to the plant environment. The filter is positioned vertically, allowing droplets to drain and collecting additional particulate from the airstream.

Stage 2: Collected mist drains off filter element

As mist particles coalesce, the droplets become large enough to run down the filter element. The filtered air exits through the clean air outlet and can be recirculated into the environment.


Choose the right filter for your application:

  • Dryflo is best suited for applications using water-soluble coolants.
    Typical particle size: 2 - 20 micron

  • Synteq XP is especially designed for mist from straight oil and smoke machining.
    Typical particle size: 0.07 - 5 micron
Stage 3: HEPA filter captures fine particles/smoke

Stage 3

For applications that generate very fine particles or smoke, or when workers are directly exposed to discharge air from the collection system, a HEPA filter is recommended. With a rated efficiency of 99.97% on 0.3 micron particles, this is the final step to filtration performance excellence.

Cross-Flow Design

Cross-flow filter design for better drainage means longer filter life. Dirty air flows horizontally through the walls of the filter in the WSOFlex, perpendicular to drainage of collected and coalesced mist.

This design promotes optimum drainage, which extends filter life and returns collected coolant for re-use. Conventional mist collectors have an upflow design impeding drainage and causing short filter life.

WSOFlex Cross-Flow Filter (left) versus Up-Flow Filter (right)

Q. What Are the Advantages of Synteq XP Media?

A. Proprietary Synteq XP Media is engineered with a blend of small and large fibers with a resin-free bonding system. The result is superior performance and longer filter life in the most challenging applications.

Q. What Size Are Mist Droplets/Particles?

A. Mist can generally be defined as a liquid droplet 20 microns in diameter or smaller. Oil-based fluids typically produce mist droplets that range from 0.5 microns to 10 microns. A smoke droplet is typically smaller, from 0.07 microns to 1 micron, and is a solid or liquid aerosol.

Q. What Determines the Performance of a Mist Collector?

A. A mist collector can be characterized by pressure drop, efficiency, and flow rate. Pressure drops affects the energy required to pull the airflow through the system. The efficiency of the system determines how clean the air will be as it leaves the collector and flow rate determines how much air will be cleaned.