INVENTORS: DANIEL J. CHO, AND WON TAE KIM

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the benefit under any applicable U.S. and/or PCT statute to U.S. Provisional Application No. 60/598,284 filed 03 August 2004, titled METHOD FOR CLEANING REVERSE OSMOSIS MEMBRANES AND FILTRATION MEDIA USING HIGH-SHEARFORCE; and to U.S. Provisional Application No. 60/645,269 filed 19 January 2005, titled HIGH-SHEAR VORTEX FILTRATION. This application incorporates by reference U.S. Provisional Application No. 60/598,284 and U.S. Provisional Application No. 60/645,269 as if both applications were fully set forth herein.

FIELD OF THE INVENTION The present invention relates generally to liquid filtration technology and, in particular, a self-cleaning non-chemical liquid filtration method and system that uses vortex technology for removing both suspended particulate matter and dissolved solids such as calcium carbonate, for residential, commercial and industrial water treatment applications.

BACKGROUND OF THE INVENTION Many residential areas that draw from ground water sources such as wells have water that contains relatively high concentrations of dissolved solids. Such water is called "hard" water and is supersaturated with mineral ions such as calcium and magnesium. Hard water creates numerous aesthetic problems for residential consumers, leaving white spots on dishes after they are cleaned and dried, prevent soap from lathering, etc. In the case of spotty dishes, the white spots are left by mineral deposits regardless of whether dishes are cleaned by hand or by a machine, after the evaporation of trace amounts of clean water from glass surfaces. The presence of mineral ions also reduces the effectiveness of soap and detergent as cleaning agents. Hence, as long as calcium or magnesium ions are supersaturated in the supply water, it is inevitable to have these undesirable aesthetic effects in residential water usage. Likewise, in commercial and industrial applications such as cooling towers as well as numerous process water applications (manufacturing of chemicals, plastics, pharmaceuticals, food and beverage, pulp and paper, mining, power generation, etc.), clean water is essential, and water that has high concentrations of mineral ions or suspended particles is a liability. Specifically in cooling tower applications, water is used to cool the equipment used in manufacturing processes and also to cool the chillers used in commercial and industrial air-conditioning. This water removes heat from various applications and by evaporating in the cooling tower, the water dumps heat into the environment. Because evaporation is so critical to cooling tower operation, mineral ions become especially concentrated and damage or reduce the life-expectancy of capital equipment. Therefore, there is a clear and present need to "soften" the hard supply water and reduce the concentration level of the mineral ions in residential, commercial and industrial applications. The conventional method of water softening is to use ion exchange or reverse osmosis. Ion exchange utilizes the exchange of ions: calcium or magnesium ions in hard water are replaced by sodium ions. In the reverse osmosis, a membrane which allows pure solvent is used to produce pure or near-pure water. The drawback of the RO is the cost of the membrane and frequent replacement of the costly membrane. The objective of the present invention is to introduce an innovative, effective and economical method for reducing the concentration of mineral ions in water. SUMMARY OF THE INVENTION The present invention uses a filtration system in order to treat water. The filter, which may be made of ceramic or other materials, has pores small enough to prevent the passage of calcium particles. As the amount of water that is treated by the filtration system increases over time, the quantity of mineral solids left behind in the filter should also increase. The highly concentrated hard water left behind is rejected through a drain, whose on-off operation will be controlled by a timer or other control mechanism. Ih the case of a residential application such as a dishwasher, the timer can be electrically connected to the operation cycle of the dishwasher such that the completion of the dishwasher operation can be recognized by the timer. It is well-known that filtration systems such microfiltration (MF) and ultrafiltration (UF) have difficulty in filtering out mineral ions that are dissolved in solution. Thus, the present invention uses a physical water treatment (PWT) technique to convert mineral ions to mineral particles through bulk precipitation. The PWT technique utilizes pulsating electric field or oscillating magnetic fields. The validity of PWT-induced bulk precipitation has been studied and reported elsewhere [ASHRAE Journal, 1/03]. The purpose of using PWT in conjunction with the filtration system is to convert dissolved mineral ions into larger suspended particles that can be filtered out by MF and UF. Therefore, the treated water should have significantly less mineral ion concentration, resulting in softer water. Further improvement can be made to the present invention by adding a recirculation pump. This improvement recirculates water for the purpose of repeatedly treat water and produce high shear flow in the annulus gap in the filter to remove mineral residue from the surface of the MF or UF system. Further improvement can be made in the present invention to make the filter medium positively charged for the purpose of dislodging mineral deposits. A high voltage DC is applied so that the membrane surface attracts negatively charged ions (HCO3", Cl", SO4""). Further improvement can be made in the present invention by having a tangential entry 41 of the circulating water into the MF/UF filtration chamber and tangential discharge out of the 2005/027703

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chamber. The objective of tangential entry and discharge is for the water to enter into a vortex flow pattern in the annulus gap formed by the filter medium and chamber. It is the object of this invention to remove deposits from the filter surface using high-shear caused by vortex flow. It is another object of the invention to extend the life of filter.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and form apart of the specification, illustrate the embodiments of the present invention and, together with the following description, serve to explain the principles of the invention. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred, it being understood, however, that the invention is not limited to the specific instrumentality or the precise arrangement of elements or process steps disclosed. Figure 1 shows a block diagram of a filtration system such as MF or UF with periodic rej ection of concentrated water used to remove suspended solids. Figure 2 shows the use of a physical water treatment (PWT) method to pre-treat water and produce bulk precipitation of dissolved mineral ions entering the filtration system, which then removes the precipitated minerals. Figure 3 shows a method to make an electrically-conducting filter positively charged. Figure 4 shows a recirculation system to remove scale deposits from the filtration medium or membrane. Figure 5 shows a recirculation system with tangential entry into and tangential discharge out of the filtration chamber to remove scale deposits from filtration medium or membrane. Figures 6A and 6B show the present invention using tangential entry and discharge of water stream in order to produce a vortex flow pattern around the filter membrane in the annulus gap between the chamber and membrane. Figure 7 shows the present invention insulation around the filtration chamber. Figures 8 A and 8B show the present invention with a tapered filtration chamber. Figure 9 shows the present invention in a cooling tower application with water recirculating around the filtration chamber, entering and leaving the chamber tangentially to produce a high-shear vortex flow pattern to maintain the filtration membrane clean during use. Figure 10 shows the present invention applied to an evaporative cooler with water recirculating around the filtration chamber, entering and leaving the chamber tangentially to produce a high-shear vortex flow pattern to maintain the filtration membrane clean during use. Throughout the drawings, like parts are given the same reference numerals.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS In describing apreferred embodiment of the invention, specific terminology will be selected for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. The present invention shown in Fig.l uses a filtration system in order to treat water. The filter, which may be made of ceramic or other materials, has pores small enough to prevent the passage of calcium particles. As the amount of water that is treated by the filtration system increases over time, the quantity of mineral solids left behind in the filter should also increase. The highly concentrated hard water left behind is rejected through a drain, whose on-off operation will be controlled by a timer or other control mechanism, hi the case of a residential application such as a dishwasher, the timer can be electrically connected to the operation cycle of the dishwasher such that the completion of the dishwasher operation can be recognized by the timer. It is well-known that filtration systems such microfiltration (MF) and ultrafiltration (UF) have difficulty in filtering out mineral ions that are dissolved in solution. Thus, the present invention shown in Fig.2 uses a physical water treatment (PWT) technique to convert mineral ions to mineral particles through bulk precipitation. The PWT technique utilizes pulsating electric field or oscillating magnetic fields. The validity of PWT-induced bulk precipitation has been studied and reported elsewhere [ASHRAE Journal, 1/03]. The purpose of using PWT in conjunction with the filtration system is to convert dissolved mineral ions into larger suspended particles that can be filtered out by MF and UF. Therefore, the treated water should have significantly less mineral ion concentration, resulting in softer water. Ia another preferred embodiment of the present invention, as shown in Figure 4, a recirculation pump 34 can be added. This improvement recirculates water for the purpose of repeatedly treating water and producing high shear flow in the annulus gap in the filter to remove mineral residue from the surface of the MF or UF system. Referring again to Figure 4, another embodiment of the present invention is shown; in this embodiment, the filter medium is positively charged for the purpose of dislodging mineral deposits. A high voltage DC is applied so that the membrane surface attracts negatively charged ions (for example, HCO3", Cl", SO4"). Further improvement can be made in the present invention by having a tangential entry 41 of the circulating water into the MF/UF filtration chamber and tangential discharge 42 out of the chamber. The objective of tangential entry and discharge is for the water to enter into a vortex flow pattern 38 in the annulus gap fonned by the filter medium and chamber. hi another embodiment is shown in Figure 7 in which insulation 54 is added to the filter in order to minimize heat loss to the surroundings. This is beneficial in cases such as a residential dishwasher 56 application using hot water 51 or in industrial applications where heat from the fluid stream is used in the process. Referring now to Fig. 8, an alternative embodiment of the present invention 16 is shown using a tapered cylinder 47 to house membrane filter 27. Fig. 9 shows the application of the present invention for cooling tower 63 water treatment which uses a circulating loop 69 around the filtration chamber to create a high-shear vortex flow pattern 38 around the membrane 27. Fig. 10 shows the application of the present invention for water treatment in an evaporative cooler 73, which uses a circulating loop 79 to create a high-shear vortex flow 38 at membrane filter 27. Figure 4 shows the present invention to make the filter medium positively charged by periodically connecting the filter membrane 27 to a power supply 3 IA for the purpose of dislodging mineral deposits by providing locally acidic conditions. A high voltage DC is applied so that the membrane surface attracts negatively charged ions (HCO3", Cl", SO4""). These negative ions reduce the pH of the membrane surface to acidic level so that the calcium scale deposits are removed periodically. This improvement would require the use of electrically conductive ceramics or other electrically conductive materials for the porous filter media. Referring again to Figure 4, this embodiment also shows the recirculation loop 35 in the present invention by adding a recirculation pump 34. This improvement uses the recirculation of water for the purpose of removing mineral residue from the surface of the MF or UF system. One example of MF or UF is a ceramic membrane filter, which has a membrane 27 coated on porous extruded ceramic material. The advantage of recirculation is the repeated treatment through the PWT device which is located on the recirculation loop. The shear force desired for the removal of the scale deposit can be increased by increasing the capacity of the pump. Figure 5 shows the present invention by having a tangential entry 41 of the circulating water into the MF/UF filtration chamber and tangential discharge 42 out of the chamber. The objective of tangential entry and discharge is for the water to enter into a vortex flow pattern 38 in the annulus gap 39 formed by the filter medium 27 and chamber 20. The circulating pump 34 will be selected such that there is enough power in the pump to produce the vortex flow pattern 38 in the annulus gap 39. The objective of the vortex flow 38 is to produce a high-shear force to detach any mineral scale deposits from the filter medium 27. Figure 6A shows the supply water entering the filter tangentially through nozzles positioned tangentially, producing a vortex flow. Water also leaves the filter tangentially through nozzles 41A and 41B located at the other end. Figure 6B shows the cut-away view of the present invention where high velocity vortex flow 38 produces a strong cleaning effect on the filter using high shear force. Figure 7 shows the present invention using insulation 54 around the filter case 20 in order to minimize heat loss to the surroundings. This is beneficial in cases such as a residential dishwasher 56 application using hot water 51 or in industrial applications where heat from the fluid stream is used in the process. Fig. 8 shows an alternative of the present invention 16 using a tapered cylinder 47 to house membrane filter 27. Fig. 9 shows the application of the present invention for cooling tower 63 water treatment which uses a circulating loop 69 around the filtration chamber as described in Fig.4 to create a high- shear vortex flow pattern 38 around the membrane 27. With additional plumbing, the filtration chamber may be backwashed (reversed flow) using tower water or supply water, entering the chamber into the center of the membrane filter then flowing out into the annulus gap 39, to further dislodge particulate matters that may have accumulated on the membrane. During backwash, the reject valve is open to the drain. Additionally, the PWT device 32 may be located in the sump (base) of the cooling tower and not necessarily inline. Fig. 10 shows the application of the present invention for water treatment in an evaporative cooler 73, which uses a circulating loop 79 to create a high-shear vortex flow 38 at membrane filter 27. Although this invention has been described and illustrated by reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made which clearly fall within the scope of this invention. The present invention is intended to be protected broadly within the spirit and scope of the appended claims. * * * * *