Inner workings of a coalescer, FAUDI coalescers for the separation of liquid phases


Filtration solutions for the treatment
of process liquids and gases.

FAUDI coalescence separator on white background
FAUDI Coalescer type_P45

Separators: Coalescers (P45)

Coalescers are also called filter water separators. Applications for the separation of liquid-liquid dispersions for single or multi-stage FAUDI coalescers can be found in many industrial sectors. The separation of hydrocarbons from a water phase (for example oil from process water) or free water from a hydrocarbon phase (for example dewatering of diesel) are the most common applications for liquid-liquid coalescers.

FAUDI coalescers are designed for the separation of a continuous and dispersed liquid phase up to the solubility limit and are available in both vertical and horizontal housing designs.

Coalescers are separators by definition. However, they can also perform filtration tasks depending on the coalescing media installed.

The FAUDI coalescers are characterized in particular by their project-specific production with adapted dimensions and/or materials and are thus individually matched to the respective application according to the customer’s wishes.

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Benefits: Your advantages
at a glance

  • Large separation surface areas
  • Suitable for high water contents in
    hydrocarbons (kerosene, diesel, oils)
  • Design with one or more separation stages
    (filter/coalescer, coalescer/separator)
  • Very high longevity of the separation elements
  • Available with instrumentation and automatic drain valves
Structure of FAUDI coalescers/filter water separators - Applications for the separation of liquid-liquid dispersions
Design layout FAUDI coalescer

Design layout

Coalescers (P45)

The coalescer consists of the following components:

1. Coalescer inlet
2. Coalescer outlet
3. Boot (collecting chamber)
4. Maintenance opening
5. Drain boot
6. Coalescer element (separation 1 step)
7. Separator element (separation 2 step)
8. Vent
9. Hand hole
10. Flushing (optional)

FAUDI coalescers/filter water separators - applications for the separation of liquid-liquid dispersions
FAUDI coalescer section view


A coalescer is a separator in which emulsions can be separated by installations such as coalescing elements. An emulsion is a disperse system of two immiscible liquids. One of the liquids forms tiny droplets which are distributed in the other liquid. The density difference, viscosity and interfacial surface tension have an important influence on the separability of the liquid phases.

The separation of the liquid phases occurs in two steps; the coalescence and gravity separation. Coalescence is the process of the smallest droplets flowing together to form a larger droplet. This separation step occurs in the incorporated coalescence medium. In order to meet various precision requirements of the coalescing process, the surface of the coalescing medium can be treated hydrophobic and/or oleophobic. The subsequent gravity separation of the coalesced droplets is mainly dependent on the residence time in the separator, i.e. the design and dimensions of the coalescer housing.

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Coalescers (P45)

Data and facts


  • Filtration fineness

    0,3 µm – 20 µm

  • Fluids

    Hydrocarbons (kerosene, diesel, oils), water and gas

  • Filter material

    Coalescer elements, cellulose folding elements, separator elements, demisters

  • Flow rate

    15 m³/h to 750 m³/h

Industries: Where they are used


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