For industrial oil skimming, there are six basic designs commonly used:
- Belt Skimmers
- Disk Skimmers
- Drum/Barrel Styles
- Mop Skimmers
- Tube Skimmers (Large and Mini)
- Floating Suction Skimmers
Belt Oil Skimmers
Belt-type oil skimmers use an endless belt of corrosion resistant steel or synthetic medium, which is lowered into the tank or vessel to be skimmed. The belt passes through resilient wiper blades where the oil is removed from both sides of the medium.
Belt machines provide a simple, dependable and cost-effective method for removing oil, grease and other hydrocarbons from water.
Disk Oil Skimmers
These oil skimmers rotate a disk-shaped medium through the liquid. Oil is wiped off and discharged into a collection container in a manner similar to belt oil skimmers. It is important to consider reach, the portion of the disk that actually gets immersed,
when looking at a disk oil skimmer. Less disk in the fluid means less oil removed. Obviously, fluctuating fluids can be a real problem for disk oil skimmers.
These are similar to the disk type, but use a rotating drum shaped medium. Compared to disk types, they are usually more rugged and have higher removal capacity. Depending on the design, these units can also be rendered ineffective by fluctuating fluid levels. Also, water pickup with this type of oil skimmer can be high.
Mop Oil Skimmers
These oil skimmers use an endless medium shaped like a rope and having mop-like tendrils that pick up the oil. As the medium leaves the liquid and enters the drive unit, it is pressed and wrung out with pinch rollers. For higher viscosity oils, the medium tends to mat down and lose effectiveness. A decant system is a must for these units, as water pickup can be very high. Also, replacement oil mops can be very expensive, so check prices on replacements before purchasing.
Large Tube Skimmers
Tube oil skimmers use a floating plastic hose that snakes out over the surface of the liquid and is then drawn back through the drive unit where oil is removed. This design requires a relatively large amount of surface area for proper operation. This oil skimmer can skim from very shallow tanks. As a rule, the removal capacity is lower than belt, drum or mop type oil skimmers.
Very similar to the large tube units, but use either a 3/16″ or a 5/16″ tube instead of 1″. The pickup rate varies from 1 quart/hour to 1.5 gph depending on the diameter of the tube. These tube skimmers are fairly compact, and can fit in tight spots. The better units will have the motor mounted underneath, to bring room required over the lip of the tank down to near zero. The 5/16″ diameter tube is preferable as it has a 1 gph removal capacity and enough stiffness to not drag on the housing and prematurely wipe off oil when being drawn into the unit.
Floating Suction Skimmers
These come in several forms, but all have a floating intake. They are most suitable for relatively thick layers of oil (1/4 inch or higher); otherwise, they tend to ingest large amounts of water. Some machines will actually emulsify oil due to churning as it passes through the suction pump. This type of oil skimmer requires a coalescing or at least a decanting unit to be at all effective. The standard drive on all units is an electric motor and gear reducer. Other drive types available.
To learn more about oil skimmers, please contact our experts at 440-543-7400 or visit our website: www.abanaki.com
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