Liquid purification or separation – With movable support – Float
Reexamination Certificate
2000-07-13
2001-12-11
Upton, Christopher (Department: 1724)
Liquid purification or separation
With movable support
Float
C210S526000, C210S540000, C210S923000
Reexamination Certificate
active
06328888
ABSTRACT:
This invention relates to a skimmer for removing a substantial proportion of certain contaminants spilled in a water environment. Contaminants for removal by the invention include oil and particulate bitumen. Particulate bitumen typically, if spilled, is spilled in the form of a mixture of the particulate bitumen in water. The particulate bitumen mixed in water with a surfactant to reduce the viscosity is commonly transported in this form to be used as a fuel supply. The skimmer is useful to remove other noxious and unwanted components. Although the skimmer is particularly useful with heavy oils and heavy contaminants it is also useful with light oils and other types of light, unwanted materials.
By water environment I include: open sea, harbour, lake, bay, sound or other body of water. The water may be fresh or salt.
By particulate bitumen in water is meant bitumen mixed with about 30% water by volume, (or other suitable percentage) in a mixture consisting mainly of bitumen particles. The bitumen particles are heavier than the water and if the bitumen-water mixture is spilled, the bitumen from the mixture soon sinks to become a suspension below the water level or a deposit on the bottom of the water environment. The invention is also particularly adapted to ‘skim’ oils, water-oil mixtures referred to as ‘heavy oils’, and some ‘medium oils’. Such heavy oil mixtures and some mixtures of the heavier medium oils temporarily float on the surface of a water environment then gradually sink below, or in some cases will immediately sink below the water level. Heavy oil and some medium oil or bitumen particles must therefore be refloated before they may be ‘skimmed’ by the device of this invention.
By contaminant I include oil, oil mixed with water, particulate bitumen and other unwanted components in a water environment.
Commonly owned U.S. Pat. No. 5,399,054 dated Mar. 21, 1995 and U.S. Pat. No. 5,743,694 dated Apr. 28, 1998 show skimmers of oil in an oil-water mixture having a sloping conveyor where the lower flight of the conveyor is arranged to travel upwardly. The conveyor has apertures therethrough. The conveyor has a lower extent of the lower flight in a trough bounded in section by a bottom wall and opposed side walls. The conveyor lower flight extends upwardly beyond the upper end of the bottom wall to an upper extent. The lower flight lower end is, in use, located just below the water line. The intent of the design is that the skimmed oil water-mixture is caused to travel upwardly with the conveyor walls scraping on the bottom wall to carry the mixture. While the skimmed mixture is travelling up the conveyor, part of the mixture, higher in proportion of water than the skimmed mixture, flows down slope over the conveyor lower flight while the mixture continuing to travel upward with the lower flight is found to be richer in oil than the oil-water mixture in the water environment. Thus it is planned that the conveyor will carry the richer mixture upward on an upper extent of the lower flight, beyond the upper end of the bottom wall, where the conveyor's oil-water mixture is to be dumped in a containment tank. If the spilled contaminant is particulate bitumen (not discussed in the prior patents), water spills down and over the surface of the conveyor lower flight while the bitumen with ‘a smaller proportion of water’ continues to ride up the upper extent.
The structure and procedure of the skimmer described in the prior, commonly owned patents has worked well. The skimmer of this invention has a similar operating mode but, in a preferred embodiment includes pusher elements which assist in the detachment of heavier liquid components over a collector area. Thus this invention is designed to perform better with contaminants which include highly viscous mixtures or components of mixtures such as heavy and some medium oils and particulate bitumen. Conversely however, the skimmer of this invention works well with light oils of limited viscosity or other light and relatively nonviscous contaminants.
The pusher elements described in the previous paragraph are preferably combined with means for shearing any contaminant hanging from the conveyor over the collector.
By contaminant material I include oil, oil-water mixtures and particulate bitumen and other unwanted material in the water environment.
Accordingly this invention provides a skimmer using an endless conveyor having a pattern of apertures extending transversely herethrough. The conveyor is driven so that the lower flight moves upwardly from a lower end located just below the water line on the outboard end over a lower extent, to an upper extent located over a collector tank or bag. The conveyor flight may thus be considered: as a lower extent where the conveyor lower flight travels on an upward slope over a bottom wall and between two side walls; and an upper extent without the bottom wall and located over the collector tank or bag or other container.
Means are described herein which act during the upward travel of the lower flight over the collection area to insert pusher elements downwardly into the apertures to tend to detach oil-water or bitumen material adhering to the conveyor. This may be adequate to detach the oil-water or bitumen-water material or the majority of it into a collecting container.
However in other applications, the oil-water mixture or bitumen-water mixture will not be fully detached or detached in sufficient quantity.
Thus the conveyor is provided with elements to enter the apertures over the upper extent of its lower flight and push materials in such apertures below the lower edges of the conveyor lower flight over a collector. Some of the contaminant material will fall of its own accord and some will be detached by the pushers to fall into the collector. Other contaminant material, still adhering to the conveyor may be detached by scraping means sometimes called a shear plate riding along lower edges of the conveyor to fall into the collector means.
In the preferred method of providing for the detachment of contaminants described above, an idler push roller is provided above the upper extent of the lower flight shortly before the lower flight starts to curve into the upper. The pusher roll is driven, preferably by the conveyor, and is provided with pusher elements which ride in the conveyor apertures as the pusher roll rotates. The pusher elements preferably serve two purposes. The rotation of the pusher roll is achieved because the conveyor walls defining the apertures contact the pusher elements to turn the idler. At the same time the pusher elements are each dimensioned to push contaminant material in an aperture to a level below the lower surface of the conveyor. A scraper or shear plate may be located to scrape the materials below the conveyor off the conveyor and pusher elements so that the scraped materials fall into the collector.
Thus, preferably, the pusher elements are designed to clear each aperture of contaminant to a large extent. At the same time there must be some clearance between the circumferential spacing of the pusher elements and the longitudinal aperture spacing between transverse walls on the conveyor, to allow rotation of the pusher element rolls (driven by the aperture transverse walls) without interference. The outer surface of each pusher element preferably is a surface of revolution concentric with the axis of the pusher roll. The maximum displacement of the element outer surfaces through the conveyor is preferably a small amount below the lower edges of the conveyor walls defining the aperture, when the element is at maximum depth in an aperture. Thus the tooth tends to push a substantial portion of the contaminant materials downwardly out of the aperture. Most of the materials then adhering to each tooth in the idler gear row are detached by a blade directed to contact the surfaces of revolution approximately tangentially at approximately the maximum depth of the pusher surface of revolution relative to the longitudinal direction of the conveyor lower flight.
REFE
Environment Recovery Equipment Inc.
Upton Christopher
Westell Robert L.
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