SKT Oil-Water Separator
Continuously Separate Tramp Oil That Cannot Rise Naturally
The SKT combines coalescing separation with proven FRIESS 1U oil-skimming technology to continuously remove dispersed tramp oil from cutting fluids, washing liquids and degreasing baths—even when the oil cannot rise naturally.
Real Equipment: System Design and On-Site Installation
On-Site Operating Video
See How Coalesced Tramp Oil Is Continuously Removed by the 1U Skimmer
This video shows the SKT operating on a central coolant system. Dispersed oil droplets combine into larger droplets in the coalescing unit, rise to the surface and are continuously discharged by the integrated FRIESS 1U oil skimmer.
- Real footage from an industrial installation
- Observe oil coalescence, accumulation and discharge
- Play directly on the page, pause at any time or exit full screen
First Make the Oil Rise—Then Remove It Precisely
The SKT is more than a conventional surface skimmer. It treats the process fluid continuously in bypass: coarse particles settle in the preliminary chamber; fine tramp-oil droplets then enter the coalescing unit, combine into larger droplets with greater buoyancy and rise to the surface; finally, the integrated FRIESS 1U skimmer continuously discharges the floating oil into a collection container while the purified liquid automatically returns to the original system.
Treatment sequence: bypass extraction → coarse-particle settling → fine-droplet coalescence → oil rises → 1U skimming and discharge → purified liquid returns.
Expand the Complete Operating Principle
The process fluid is pumped through the SKT in a bypass stream by a diaphragm pump. In the preliminary chamber, entrained coarse contamination first settles out. The tramp oil then enters the coalescing separator, where dispersed fine droplets combine until they have sufficient buoyancy to rise to the liquid surface.
At the surface, the integrated FRIESS 1U oil skimmer continuously transfers the separated oil into a collection container, while the de-oiled liquid flows through the outlet chamber and returns to the process tank.
An optional FRIESS magnetic filter can be integrated to remove ferromagnetic particles down to approximately 1 µm.
Why Choose the SKT?
Continuous Oil Removal for Stable Process-Fluid Quality
- Extend process-fluid service life — continuously remove tramp oil and reduce complete fluid changes and tank-cleaning downtime.
- Stabilize machining and washing quality — reduce oil carry-over, stains and quality risks in downstream processes.
- Reduce chemical and fresh-fluid consumption — keep degreasing baths, washing liquids and emulsions effective for longer.
- Improve the working environment — reduce surface oil layers, odours and conditions that promote anaerobic bacteria.
- Lower total treatment costs — reduce waste-fluid volume, process-fluid losses and disposal expenses.
Which Operating Conditions Need the SKT Most?
- Continuous circulation or strong turbulence — tramp oil is dispersed and cannot form a stable surface layer.
- Fine droplets remain suspended — a conventional skimmer only reaches the surface and cannot remove oil that has not risen.
- Continuous ingress of hydraulic, slideway or quenching oil — bypass separation is needed to prevent accumulation.
- A surface oil layer and odour develop — the oil layer restricts air contact and threatens fluid stability.
- Oil stains or quality fluctuations appear on parts — tramp oil interferes with washing, coating, machining or quenching.
- Oil contamination and ferromagnetic particles occur together — an optional FRIESS magnetic filter provides combined purification.
- Fluid changes, top-ups or chemical additions are too frequent — process-fluid consumption and waste disposal must be reduced.
Technical Data
- SKT 10 / SKT 20 / SKT 40
- Flow rate: 300 / 600 / 1,200 L/h
- Oil discharge capacity: max. 30 L/h
- Operating temperature: 40 / 70 °C
- pH range: 5–14
- Dimensions
- Width: 440 / 440 / 510 mm
- Length: 600 / 900 / 1,660 mm
- Height: 1,200 / 1,280 / 1,230 mm
- Tank capacity: 100 / 200 / 400 L
- Recommended system volume: approx. 7,500 / 15,000 / 30,000 L
Real Applications: Continuous Oil Removal in Different Operating Conditions
A FRIESS Skimmtelligent oil separator keeps tramp oil below 50 L in a 30 m³ central coolant system, extends emulsion life to one year and pays back in under six months.
After oil-bath hardening, a FRIESS Skimmtelligent 20 removes tramp oil from degreasing wash water so components can be cleaned reliably for downstream processing.
The FRIESS Skimmtelligent Mini oil separator removes finely dispersed tramp oil from emulsions and wash water, reducing microbial growth and extending fluid life.
Two Skimmtelligent 20 oil separators reduce tramp oil and ferrous particles in a 16,000-litre central coolant system for railway-wheel machining.
FRIESS Skimmtelligent continuously removes oil from a degreasing bath, reducing chemical consumption, stabilising the process and protecting coating quality.
Frequently Asked Questions
Q1: How does the SKT differ from a conventional oil skimmer?
A conventional skimmer primarily removes oil that has already reached the surface. The SKT first uses a coalescing unit to combine fine oil droplets dispersed in the process liquid, allowing them to rise. An integrated FRIESS 1U skimmer then removes the separated oil. This is particularly effective where the liquid is continuously circulating and tramp oil cannot rise naturally.
Q2: Which SKT sizes are available and how should I select one?
The SKT 10, 20 and 40 provide flow rates of 300, 600 and 1,200 L/h and are recommended for system volumes of approximately 7,500, 15,000 and 30,000 L respectively. Final selection also depends on the tramp-oil load, oil viscosity, temperature, process-fluid condition and required cleanliness.
Q3: Which liquids can the SKT treat?
It is suitable for cutting fluids, grinding fluids, industrial washing liquids, degreasing baths and quenching emulsions contaminated by hydraulic oil, slideway oil, lubricating oil or quenching oil. It can be installed as a bypass system on individual tanks or central circulation systems.
Q4: What level of improvement can the SKT deliver?
Results depend on the oil load and operating conditions. In existing applications, washing-water replacement intervals increased from one week to three weeks, while a central quenching-emulsion project achieved a payback period of less than six months. A site assessment or rental trial is recommended to confirm the expected result.
Q5: Does the SKT require consumables?
No filter paper or cartridges are required for normal operation. The SKT treats the liquid continuously in bypass while production continues. An optional FRIESS magnetic filter can be added to remove ferromagnetic particles at the same time.
Let Us Select the Right SKT for Your Actual Operating Conditions
The correct SKT configuration depends on the system volume, daily tramp-oil load and condition of the process fluid. The following information helps us identify the appropriate model and options:
- Tank or central-system volume
- Process-fluid type, temperature and pH
- Type of tramp oil and approximate daily ingress
- Whether the liquid circulates continuously or is subject to strong turbulence
- Whether ferromagnetic particles must also be removed
We can provide an application assessment, model recommendation and rental-trial proposal.
After receiving your application data, we will recommend the appropriate SKT model and optional equipment for your treatment target.
Other Product Options
Depending on your required flow rate, mobility, and oil removal needs, you may also consider the following products.
Separates floating oil, removes particles and circulates coolant for purification. Its compact, mobile design is ideal for servicing multiple machine tools while helping extend coolant life and reduce fluid-change frequency.
Separates floating oil, removes particles and circulates coolant for purification. Its modular configuration supports higher treatment demands and helps maintain stable coolant quality in demanding machining operations.
