Wide-ranging series for oil mist separation and oil recirculation

FRIEDRICHS FILTERSYSTEME offers a comprehensive range of oil mist separators (demisters) for the separation and recirculation of oil mist in various industrial applications. Our demisters are designed to effectively remove oil mist particles from air, ensuring that the working environment is clean and healthy while also conserving valuable resources.

Benefits of using Friedrichs Filtersysteme oil mist separators:

  • Efficient oil mist separation: our demisters achieve a separation efficiency of up to 99.9%, ensuring that even the smallest oil particles are removed from the air.
  • Oil recirculation: the separated oil is collected and recirculated back into the system, reducing oil consumption and waste.
  • Environmental protection: by preventing oil mist emissions, our demisters help to protect the environment from pollution.
  • Health protection: oil mists can be respiratory health hazards, and therefore our demisters help to create a clean and healthy working environment.
  • Cost savings: by reducing oil consumption and waste, our demisters can help to reduce process costs.
  • Easy to install and use.
  • Almost no maintenance.
  • Low pressure drop.


Applications of Friedrichs Filtersysteme oil mist separators:

  • Various applications in sealing gas discharges from turbo compressors, expanders, turbines and vacuum pumps
  • Crankcase breathers in combustion engines
  • Power generation: our demisters are also suitable for power generation applications, in which they are used to remove oil mists from turbine exhausts and other sources.
  • Metalworking: our demisters are widely used in metalworking applications, where they remove oil mist from machinery such as CNC and grinding machines.

Friedrichs Filtersysteme offers a wide range of oil mist separators to suit a variety of applications. Our demisters are available in a variety of sizes and configurations to meet your specific needs. Depending on your configuration, we offer individual or modular systems with round, oval or rectangular filter elements. Custom designs depending on available space and separation requirements are also possible.


Working principle




  • mechanical separation by finely graded filter system.
  • oil return line back into the system or into an external tank.
  • optional suction fans will further reduce the already low pressure drop.
  • separation up to 99.97%, based on the entire range of droplet sizes, has been proven.

The air loaded with particles flows through the inlet flange into the demister housing. The built-in demister insert – consisting of up to three elements, depending on the design – separates the particles in the supply air by means of sieving, impact and gravitational and electrostatic effects in the deeply staggered package of oleophilic fibres, during the flow from outside to inside, and directs them downward. The air, now freed from its load of particles, is discharged via the outlet tube on the upper part of the demister. If your system requirements mean that  an additional suction effect is desired from the demister, various optional fans are available for this purpose.



A prerequisite for proper functioning of the demister is the correct piping configuration for the inlet and outlet. The inlet piping must be mounted such that it rises slightly as it approaches the demister to prevent liquid accumulation. The outlet piping (if needed) should also be mounted such that it rises slightly in the direction moving away from the demister. If the pipes are extremely long or the outlet opening is configured unfavourably, the installation of an additional blower may be necessary (optionally available). A flexible hose of about 1 m in length between the outlet of the casing and the outlet piping makes the dismounting of the upper part of the casing much easier because the pipe connection doesn´t need to be loosened. The main mounting position is vertical, i.e. the demister axis must be adjusted vertically. The demister is fastened with the four stay bolts of the inlet flange to a counter flange fitting. A gasket (included) must be fitted between the two flanges. If the inlet piping is stable enough and if no vibrations occur, an additional fastening will not be necessary. The upper part of the casing can be rotated around its axis to the preferred blow-off direction after loosening the uppermost clamp ring. The oil drain should be designed to include a siphon such that a liquid barrier separates the air intake from the outlet. This siphon must be filled with medium before start up. An overview of the range of available oil drains with siphons is provided in a special data sheet. After transportation or storage lying down, the upper part of the casing must be taken off after mounting to check that the demister insert is properly fitted (centred fitting inside the casing is recommended). If the insert is not properly positioned, lift it a little and let it fall down again to allow gravity to help ensure that the insert is sitting in its proper position. If a suction fan is installed, check that it rotates freely after mounting the upper part of the casing.