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Oil Separators

Use the Oil Separator for mixed-in oils!

Oil does not float in your process fluids, but mixes or emulsifies? This is often the case in washing and degreasing processes, where the washing water is often highly turbulent due to high pump capacities or immersion processes.

Unfortunately, oil skimmers do not provide a remedy here. Instead, the Oil Separator must be used, since it first settles the fluid in a bypass flow.

The solution from FRIESS – The Oil Separator Skimmtelligent

Our oil separator Skimmtelligent settles the bypass flow so that heavy particles sink to the bottom and the oil droplets in turn rise to the surface. To improve the separation of oil and fluid, coalescers are used which combine small oil droplets to larger droplets, thus increasing buoyancy. The floating oil is prevented from flowing further thanks to a baffle, while the cleaned fluid flows underneath it and back into the tank.

Conventional Oil Separators separate the oil by means of overflow processes, such as spilling over a separating edge. However, since this is usually extremely unreliable and error-prone, the FRIESS Skimmtelligent uses the FRIESS oil skimmer Model 1U for this purpose. This removes the oil reliably and thus prevents operating errors.

The advantages at a glance:

  • The FRIESS Skimmtelligent works independently from production and removes even the smallest amounts of tramp oil.
  • Increase the service life of cooling  emulsions and washing water significantly with FRIESS by continuously de-oiling your fluids.
  • Save significant amounts of money on the purchase and disposal of coolant concentrates and detergents.
  • As our systems are made using stainless steel, they can be used in the vast majority of applications without any problems.
Bei vermischenden Ölen kommen FRIESS Ölabscheider zum Einsatz
Oil Separators Skimmtelligent Mini
A bypass unit used to separate oil that does not float.
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Der Skimmtelligent mini löst vermischte Öle
Oil Separators Skimmtelligent
An Oil Separator equipped with FRIESS oil skimmer technology.
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Der Ölabscheider Skimmtelligent wird im Nebenstrom eingesetzt, um vermischtes Öl abzuscheiden

Application examples

prepare cooling-lubricants
Prepare cooling lubricants

Many manufacturing companies rely on coolant in their manufacturing processes. These coolants decrease the heat generated by friction in machining processes and also ...

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Oil separator Skimmtelligent used ...

A big manufacturer of components for engine and drive train uses a central emulsion tank with a volume of 30 m³ emulsion.

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Oil separator Skimmtelligent at ...

The company used an oil skimmer model 3H for more than 15 years in order to remove the oil from the washing water. The oil skimmer operated during the night shift.

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Advantages of the Skimmtelligent separator

The operation of an oil separator is based on different density ratios between a volatile liquid such as mineral oils, petrol and another medium such as water. The lighter oil or petrol collects on the water’s surface due to buoyancy and can be separated from the liquid.

Applications of an oil separator from FRIESS

The Skimmtelligent separator from FRIESS settles the water in the bypass stream so that the smallest oil particles, which would otherwise partially form an emulsion with the water, can settle and rise to the surface. To further increase the separation behaviour of oil and water, coalescence elements (coalescence = bringing together of separated substances) ensure that the smallest oil particles combine and thus the volatile liquids increase their buoyancy. At the surface, the floating tramp oil can be removed up by an integrated tube skimmer so that they are removed as soon as they rise to the water’s surface. This prevents too much oil from accumulating in the separator, which could lead to oil being carried away in the liquid flow of the separator. Heavy particles such as dirt are already removed in the preliminary stage by settling. In the case of metallic contaminants, a FRIESS magnetic filter can be integrated as an optional extra.

FRIESS Skimmtelligent separators are mobile and can therefore be used to concurrently keep various systems free of oil.

Applications of an oil separator from FRIESS

Coolant maintenance

During the machining of metal components, tramp oil in various forms is always introduced into the coolant. If this tramp oil floats up in the coolant tanks, it is often removed with oil skimmers. In the design and planning of new lubrication systems, the trend is to make the tanks as compact as possible in order to make the footprint of the machine tool as small as possible. This means that the coolant in the tank is always turbulent because the pump capacity is very high compared to the volume of the tank. This prevents tramp oil from settling on the surface, in which case an oil skimmer is ineffective.

In order for the tramp oil to rise, the coolant must be able to settle. An oil separator in a bypass connection does precisely that. The coolant is settled, the oil can rise and is then removed. In addition, any sludge carried along can settle in the sludge trap. Clean coolant then flows back into the coolant tank for further use.

Washing Water treatment

Washing processes are used in various manufacturing processes to remove oil and particles from components. The oil that needs to be removed from workpieces with a washing fluid is often discharged from the system when the wash fluid is replaced. Treatment of the washing liquid rarely takes place. Continuous removal of the oil with an oil separator leads to considerably lower operating costs due to a significantly longer service life of the washing liquid. In order to maintain the washing effect of the washing liquid, treatment is necessary.

Washing water basins are often very turbulent. This prevents tramp oil from settling on the surface and sludge from settling on the bottom.  Parts of the tramp oil and sludge are unnoticed in the liquid. To remove the “hidden” impurities, the liquid must first be settled so that the oil can rise and the sludge can settle in the sludge trap. This separates the washing liquid from oil and dirt and extends the service life.

Advantages of mobile oil separators

Especially if there are various small basins in which tramp oil collects, it is not economical to install an oil separator or oil skimmer at each basin. Irrespective of the higher investment requirement this entails, it is often not technically possible or sensible to equip every coolant tank or washing system with a separator.

For such cases, mobile oil separators are designed that can be moved from system to system and put into operation there in a few simple steps. It is important here that the separator’s pump is self-priming in order to make commissioning at a new tank as simple as possible.

In the standard version, all FRIESS oil separators are designed as mobile oil separators. On request, we are also able to design them as stationary units.

Reduction of disposal and operating costs

By using a mobile oil separator you are able to extend the service life of process fluids. By treating the fluid, the desired result is maintained for longer and negative effects on the process can be avoided.

Due to the increased service life of the process fluids, they are disposed of less frequently, which on the one hand results in a reduction of disposal costs, and on the other hand process fluids such as cooling lubricants or degreasing agents have to be purchased less frequently. The extent of this reduction depends on the actual condition and the amount of tramp oil previously introduced.

Oil separator versus oil skimmer

Oil skimmers and oil separators are used in different applications and are therefore not directly comparable. Although both have the same goal, to remove oil from another liquid, they act in a fundamentally different way. An oil skimmer is usually used where oil is already floating on the fluid’s surface. This floating oil can then be easily removed with the oil skimmer.

Oil separators are often used to remove oils that are not yet floating. Due to the settling of the water in the separator, often enhanced by a coalescence process, free oil droplets have the opportunity to rise to the surface and are then retained by means of a partition wall. Thus, an oil separator is used where an oil skimmer cannot be used, i.e. where little to no oil is floating.

You can find more information on how oil skimmers work and their areas of application here.

Oil skimmer manufacturer – FRIESS GmbH

For more than 50 years, FRIESS has been producing systems and equipment for the treatment of wastewater and process fluids. The product range includes oil separators, oil skimmers, magnetic filters, electrostatic oil cleaning systems and other sophisticated technologies. Made in Germany and already in use with many satisfied customers. Buying from the manufacturer FRIESS offers many advantages.

Buying an oil separator – this is how it works

What to consider before buying

Various parameters must be considered before the right oil separator can be determined. These include the fluid, temperature, liquid volume, oil ingress, etc. Before buying an oil separator, it is important to take stock of your situation in order to be able to assess which requirements must be met.

In many cases, our two mobile oil separators can be used:

Our mobile systems also offer the advantage that structural changes are unnecessary in most cases and that several  tanks or systems can be de-oiled with an oil separator.

Expert advice before buying

You need an oil separator? No problem! A consultation is completely free. Just approach us and we will help you answer your questions and help you find the best solution for your use case. We will be happy to advise you on all your questions by telephone or e-mail.


You need a spare part or have questions about our Skimmtelligent? Service is very important to us and satisfied customers are what we strive for.

Download technical features FRIESS oil separator

FAQ → Questions and answers

Why should an oil separator be used?

The unhindered increase of oil quantities in a process liquid, leads to a lower efficiency of this liquid. By removing this oil, a process fluid can remain effective for longer and deliver the expected results. This helps you to save costs and conserve resources.

What maintenance is necessary with an oil separator?

Depending on the design and function of an oil separator, there are different requirements for maintenance and inspection. Maintenance can be carried out weekly, monthly and semi-annually by instructed personnel. However, the mobile oil skimmers from FRIESS are low-maintenance and easy to operate. With our Skimmtelligent oil separator, you always have full control.

We will be happy to answer your questions personally.

How much does an oil separator cost?

Depending on the size and complexity, the price of an oil separator can vary greatly. There is almost no upper limit. Small separators usually start in the low four-digit range, depending on complexity and safety features.

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