Skimmer (machine)

An oil skimmer is a device that separates oil floating on a liquid surface. They are used for a variety of applications such as oil spill response, as a part of oily water treatment systems, removing oil from machine tool coolant and removing oil from aqueous parts washers. Oil skimmers were used to great effect to assist in the remediation of the Exxon Valdez spill in 1989. Oil skimmers are different to Swimming pool sanitation skimmers that are designed for a related but different purpose.

There are many different types of oil skimmer and each type has different features. It is important to understand the features before employing a particular skimmer type.

Some factors to consider are:

The use of skimmers in industrial applications is often required to remove oils, grease and fats prior to further treatment for environmental discharge compliance. By removing the top layer of oils, water stagnation, smell and unsightly surface scum can be reduced. Placed before an oily water treatment system an oil skimmer may give greater overall oil separation efficiency for improved discharge wastewater quality. It should be noted that all oil skimmers will pick up a percentage of water with the oil which will need to be decanted to obtain concentrated oil.

There are three main types of oil skimmer: weir (manual or self-adjusting) and oleophilic and non-oleophilic (disc, drum, belt, tube, brush,mop, grooved disc, grooved drum):

Weir skimmers function by allowing the oil floating on the surface of the water to flow over a weir. There are two main types of weir skimmer, those that require the weir height to be manually adjusted and those where the weir height is automatic or self-adjusting. Whilst manually adjusted weir skimmer types can have a lower initial cost, the requirement for regular manual adjustment makes self-adjusting weir types more popular in most applications. Weir skimmers will collect water if operating when oil is no longer present. To overcome this limitation most weir type skimmers contain an automatic water drain on the oil collection tank.

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Oleophilic skimmers function by using an element such as a drum, disc, rope or mop to which the oil adheres. The oil is wiped from the oleophilic surface and collected in a tank. As the oil is adhering to a collection surface the amount of water collected when oil is not present will be limited.

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Wikipedia