Hydroclones are commonly used to separate suspended particles from liquids. In a typical embodiment, pressurized feed liquid (e.g. waste water) is introduced into a conically shaped chamber under conditions that create a vortex within the chamber. Feed liquid is introduced near the top of a conical chamber and an effluent stream is discharged near the bottom. Centrifugal forces associated with the vortex urge denser particles towards the periphery of the chamber. As a result, liquid located near the center of the vortex has a lower concentration of particles than that at the periphery. This “cleaner” liquid can then be withdrawn from a central region of the hydroclone. Examples of hydroclones are described in: U.S. Pat. No. 3,061,098, U.S. Pat. No. 3,529,544, U.S. Pat. No. 5,104,520, U.S. Pat. No. 5,407,584 and U.S. Pat. No. 5,478,484. Separation efficiency can be improved by including a filter within the chamber such that a portion of the liquid moving to the center of the chamber passes through the filter. In such embodiments, cyclonic separation is combined with cross-flow filtration. Examples of such embodiments are described in: U.S. Pat. No. 7,632,416, U.S. Pat. No. 7,896,169, US2011/0120959 and US2012/0010063. Aspects of cyclonic separation pose challenges for cross-flow filtration. For example, feed flow velocities used to create a vortex in cyclonic separations can result in accelerated wear or fouling of the membrane used in cross-flow filtration. This condition is exacerbated when utilizing feed fluids having high solids content.
USPTO Backgrounds
USPTO Backgrounds