SMT500 Oil-Water Separator
Fixed Installation for Continuous Purification of Oily Process Fluids
The FRIESS SMT500 is permanently connected to a single tank or process-fluid system. Operating in an independent bypass loop, it continuously removes floating oil and coalescible dispersed oil droplets from washing liquids, degreasing baths, cutting fluids, grinding fluids and quenching fluids. The cleaned liquid returns to the original tank by gravity.
The standard configuration retains larger solid particles. For fine ferromagnetic particles, the optional FRIESS FMF 240 magnetic filter can be added.
600 L/h
Nominal flow rate
350 μm
Stainless-steel basket strainer
Continuous fixed operation
Fixed installation · bypass loop
Down to 1 µm
with optional FMF 240
Continuous Bypass Purification in Operation
This field video shows the SMT500 operating as a permanently installed bypass system. Oily liquid is drawn from near the liquid surface, passes through solids prefiltration and oil-water coalescing, and the cleaned liquid returns to the original tank by gravity while separated waste oil is collected.
• Fixed bypass operation without stopping the production equipment
• Continuous tramp-oil removal helps slow fluid oxidation and odour formation
• Reduces fluid changes, tank cleaning and routine maintenance
Four Steps in Continuous Bypass Purification
From surface pickup to clean-liquid return, the SMT500 treats the fluid continuously in a fixed bypass loop without modifying the machine’s existing supply circuit.
01 Floating Surface Pickup
The floating suction device follows changes in liquid level and preferentially draws the oil-rich layer near the surface.
02 Basket Prefiltration
A 350 µm stainless-steel basket strainer retains larger chips and solid particles, reducing the risk of blockage in the downstream separation stage.
03 Coalescing Separation
Fine dispersed oil droplets adhere to the oleophilic coalescing medium, collide and combine into larger droplets.
04 Oil Discharge and Clean-Liquid Return
The enlarged oil droplets rise and are discharged as a concentrated oil phase, while the treated liquid returns to the original tank by gravity.
Standard Configuration and Optional Upgrade
Select the configuration according to the contaminants in the fluid. The standard unit focuses on oil-water separation and retention of larger solids; the magnetic filtration stage is recommended where fine ferromagnetic particles are present.
Standard Configuration
Oil-Water Separation and Solids Prefiltration
• Nominal flow rate: 600 L/h
• Continuous removal of floating oil and coalescible dispersed oil droplets
• 350 µm stainless-steel basket strainer
• Retains larger chips and solid particles
• Fixed bypass operation for one tank or process-fluid system
Physical coalescing separation—no chemical additives required.
Optional Configuration
FRIESS FMF 240 Magnetic Filter
• Removes fine ferromagnetic particles
• Filtration performance down to 1 µm for ferromagnetic particles
• Suitable for grinding and cast-iron machining applications with high loads of fine magnetic particles
• Combines with the SMT500 for simultaneous control of tramp oil and solid contamination
Note: The 1 µm rating applies only to the optional FMF 240 and only to ferromagnetic particles. The standard SMT500 basket strainer is rated at 350 µm.
SMT500 Technical Data
The following values apply to the standard SMT500 configuration. The final system can be adapted to tank conditions, contaminant type and installation requirements.
Model
Nominal flow rate
Oil-water separation method
Oils treated
Standard prefilter
Operating mode
Installation
Clean-liquid return
Optional equipment
Optional filtration performance
SMT500
600 L/h
Physical separation with oleophilic coalescing media
Floating oil and coalescible dispersed oil droplets
350 µm stainless-steel basket strainer
Independent bypass loop
Fixed installation serving one tank or process-fluid system
Gravity return to the original tank
FRIESS FMF 240 magnetic filter
Down to 1 µm for ferromagnetic particles
▌ Operating Principle
From Surface Pickup to Clean-Liquid Return
Installed in a fixed bypass loop, the SMT500 independently performs pickup, prefiltration, coalescing and return without altering the machine’s existing fluid-supply circuit.
Surface Pickup
The floating suction device follows the liquid level and continuously draws tramp oil and process fluid from near the surface.
Particle Prefiltration
The mixture first passes through a 350 µm stainless-steel basket strainer, which retains larger solids and protects the downstream separation stage.
Coalescing Separation
Fine oil droplets collect on the coalescing elements, merge into larger droplets and rise to form a separate oil layer in the separation chamber.
Oil Discharge and Fluid Return
Separated waste oil is discharged into a collection container, while the cleaned liquid returns to the original tank by gravity to complete the continuous bypass loop.
▌ Coalescing Separation
Small Oil Droplets First Coalesce, Then Rise More Quickly
After passing through the 350 µm stainless-steel basket strainer, the oil-contaminated liquid enters the separation stage and flows through an oleophilic coalescing medium. Fine dispersed oil droplets are captured on the medium and progressively collide and merge into larger droplets.
As the droplets grow, their rising velocity increases. They accumulate as a separate oil layer in the left-hand oil zone shown in the image and are discharged; the separated liquid enters the clean-liquid zone on the right and returns to the original tank by gravity. The entire process is physical and requires no chemical additives.
• Captures fine coalescible dispersed oil droplets
• Combines them into larger droplets for faster gravity separation
• Concentrates the oil phase for discharge while clean liquid returns continuously
More Than Floating Oil: Capturing Coalescible Oil Droplets in the Fluid
The SMT500 operates in a fixed bypass loop and is suitable for both floating oil and coalescible oil droplets dispersed in the process fluid. Unlike belt or disc skimmers, which mainly remove oil from the liquid surface, the SMT500 uses coalescing separation to enlarge fine oil droplets so that they rise and can be discharged.
Typical Applications
Parts-Washing Tanks
Removes lubricating and rust-preventive oils carried into the washing liquid
Machine-Tool Fluid Tanks
Removes hydraulic and slideway oils entering cutting or grinding fluids
Quenching-Fluid Tanks
Removes floating oil and coalescible oil droplets to reduce oil accumulation
Degreasing and Surface-Treatment Tanks
Purifies degreasing baths and helps stabilise downstream treatment quality
SMT500 Frequently Asked Questions
What tank size is the SMT500 suitable for?
Tank capacity alone is not sufficient for selection. Oil load, required turnover rate and daily operating time must also be considered. With a nominal flow rate of 600 L/h, the SMT500 is suitable for fixed connection to an individual machine tank, a small washing tank or a single process-fluid circulation system.
Can the SMT500 remove metal chips?
The standard 350 µm stainless-steel basket strainer retains larger chips and solid particles. For fine ferromagnetic metal particles, the optional FRIESS FMF 240 magnetic filter provides filtration performance down to 1 µm for ferromagnetic particles.
Will fixed bypass operation interfere with the existing fluid-supply system?
Normally not, provided the unit is connected and the flow rate is set correctly. The SMT500 draws liquid from the tank through an independent bypass loop and returns the treated liquid to the same tank by gravity, so it operates independently of the machine’s existing supply circuit.
Can the SMT500 treat emulsified oil?
The SMT500 is intended for floating oil and coalescible dispersed oil droplets. It is not suitable for oil that has formed a stable emulsion. If the contamination state is unclear, please provide a fluid sample or site photographs for evaluation.
Which tanks can the SMT500 serve as a fixed installation?
Typical applications include washing-liquid tanks, degreasing baths, cutting-fluid tanks, grinding-fluid circulation systems and quenching-fluid tanks. Final configuration depends on tank volume, oil type, contamination load and available installation space.
Does the SMT500 include UV or another disinfection system?
No. The SMT500 uses physical prefiltration and coalescing separation and does not include UV, ozone or another disinfection system. Its primary function is to remove floating oil and coalescible dispersed oil droplets while retaining larger solids in the 350 µm basket strainer.
Beyond cost savings, FRIESS oil skimmers, electrostatic oil cleaners, magnetic filters, coolant purification systems, oil-water separators and vacuum oil purifiers offer many additional benefits.
We would be pleased to explain how they can help in your application.