The content of this blog post has been provided courtesy of Abanaki Oil Skimmers.
Have you ever heard the old saying, “Oil and Water Don’t Mix?” This is also holds true in metal finishing.
The relationship between oil and water in a mixture is well-known and governed by two physical properties:
- Specific Gravity: Most hydrocarbons have a lower specific gravity than water. Without agitation, oil separates from the water and floats to the surface. These oils are known as LNAPL’s – Light Non-Aqueous Phase Liquid. Oils (and other compounds) that sink in water have a higher specific gravity and are known as DNAPL’s – Dense Non-Aqueous Phase Liquid.
- Surface Tension and Affinity: Normally, oil bonds more tightly to itself and other materials than to water. This affinity and differences in surface tension between oil and water, cause oils to adhere to a skimming medium.
Although designs vary, all oil skimmers rely on specific gravity, surface tension and a moving medium to remove floating oil from fluid’s surface.
Floating oil and grease cling to skimming media more readily than water, and water has little infinity for the media. This allows skimming media in the shape of a belt, disk, drum, etc. to pass through a fluid surface to pick up the floating oil and grease with very little water. This oily material is subsequently removed from the media with wiper blades or pinch rollers.
Oil skimmers are simple, dependable and effective tools for removing oil, grease and other hydrocarbons from water and coolants. Often, an oil skimmer by itself can achieve the desired level of water purity. In more demanding situations, oil skimming is a cost-effective means of removing most of the oil before using more complicated and costly treatments such as coalescers, membrane filters and chemical processes.
Grease skimming involves higher viscosity hydrocarbons. Oil skimmers must be equipped with heaters powerful enough to keep grease fluid for discharge. If the floating grease has formed into solid clumps or mats, a spray bar, aerator or mechanical apparatus can be used to break up the grease matts and facilitate removal.
Asterion carries the complete line of ABANAKI Oil Skimmers. Please contact us for further details.