Skimmers are used to remove material floating upon a liquid (by “material” means any solid or liquid substances). The material may be desirable, as for example a valuable liquid layer floating upon another liquid, or undesirable, as for example a pollutant floating upon a liquid. Some familiar situations include, by way of example, the removal of oil floating on water, removal of debris floating on the surface of a swimming pool, and the separation of differing liquid layers in an industrial process.
A common aspect in the ability to remove material floating on a liquid by skimming is the physical property of specific gravity. Materials (including solids and liquids) with a lower specific gravity will float at the surface of a liquid having a higher specific gravity.
In a typical skimmer device, a weir is provided in combination with movement of a liquid to which skimming is to occur. The weir is buoyant so that it floats in relation to the level of the liquid, and as the liquid is caused (as for example by a pump) to move over the weir, only a top layer of the liquid, which includes the floating material, passes over the weir. As a result, the bulk of the liquid does not pass over the weir, and only a relatively smaller volume top layer passes over the weir which includes most, if not all, the floating material to be removed. Given time, it is desired that all the floating material will have passed over the weir, but left behind (that is, not passed over the weir) is the bulk of the liquid which is now freed of the floating material.
While weir-type skimmers work well, generally they are not compact, usually the weir being in the form of a linear plane which is hinged at one end, and, therefore, the entire top surface of the liquid is not likely to be drawn over the weir unless the liquid is also caused to have a circulation current so that all the surface has a chance to become near the weir over time. Another problem associated with hinged, stationary or otherwise mechanically supported weirs, is their inability to regulate the weir action during wave action of the liquid, whereupon lesser and greater top surface depths pass over the weir in response to the waves striking the weir.
Accordingly, what remains needed is a skimmer system which regulates its weir action very favorably even in wave action of the liquid, and which further draws the top surface of a liquid from all directions so that a circulating current of the liquid is unnecessary for the weir to remove floating material from the liquid over time.