Oleophilic and Hydrophobic Surfaces: Why Vens Skimmers Pick Oil and Reject Water

Every belt, tube, disc and drum oil skimmer works the same way. A moving surface passes through the oil layer, oil clings to it, and a wiper scrapes the oil off into a collection trough. The motor, the frame and the wiper matter, but the surface does the real work. If the surface holds oil well and sheds water, the skimmer recovers more oil and sends back almost all of the water. If it does not, you collect oily water instead of oil.

That is why every Vens belt, tube and disc uses a surface that is both oleophilic and hydrophobic.

What the two words mean

• Oleophilic means oil-attracting. Oil wets the surface and spreads over it in a continuous film, rather than sitting on it as beads.

• Hydrophobic means water-repelling. Water beads up and runs off the surface instead of clinging to it.

A surface that is both selects oil. As it rises out of the liquid, it carries a film of oil and drains the water back into the tank before it reaches the wiper.

Why this matters in practice

• More oil per pass. A surface that oil wets fully carries a thicker, unbroken film, so each metre of belt or each turn of a disc removes more oil.

• Less water in the recovered oil. Water that drains away at the surface does not end up in your collection tank. That means smaller collection tanks, fewer drum changes and lower disposal costs. In plants that reuse the oil, it also means oil of higher value.

• Thin layers are not missed. An oleophilic surface picks up even a thin sheen that a weir or suction skimmer would leave behind or would take with a lot of water.

• Steady performance. A surface that oil wets easily keeps working as the oil layer thins. Removal does not stop when the easy oil is gone.

Belts, tubes and discs

Belts

Vens skimmer belts are made from oleophilic polymer with a water-repelling surface. They come in widths and lengths to suit pits, sumps and tanks. Normal-temperature (NT) grades are used for most effluent duties and high-temperature (HT) grades for hot process water. A belt reaches deep and narrow pits and works with varying levels, and it suits light to heavy oils.

Tubes

Tube skimmers use an endless oleophilic, hydrophobic polymer tube that floats across the surface and draws oil from a wide area. They suit irregular tanks and ponds, and the tube rides up and down with the level.

Discs and drums

Discs and drums give high removal rates from large separators, clarifiers and spill sites. The oleophilic surface on each disc collects oil on both faces, and grooved discs add surface area for heavier oils. Wipers clean both faces on every turn.

Getting the most from the surface

• Match the material to the oil and temperature. Hot water, aggressive chemicals and very heavy oils each need the right grade. Tell us the oil, temperature and pH when you enquire.

• Keep the wipers in good condition. A worn wiper leaves oil on the surface, and that oil goes back into the tank.

• Run at the right speed. Too fast and the surface carries water; too slow and oil is left behind. Our engineers set the speed for your duty.

• Replace belts and tubes when worn. Surface damage reduces both pick-up and water rejection. Genuine Vens replacement belts are listed in our online shop.

The result

A skimmer is only as good as the surface that touches the oil. By making that surface both oil-attracting and water-repelling, Vens skimmers recover more oil, with less water, for longer. That is how many of our customers recover their investment within days. See how a skimmer can pay for itself in a day.

Ask our engineers which belt, tube or disc suits your oil, or browse Vens oil skimmers.