# US 9,517,949 B2 · Water treatment apparatus with circulating flow path and water treatment method using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,949 B2 - Document ID: US9517949B2 - Status: Granted - Kind: B2 - Application number: 13/943,696 - Filed: 2013-07-16 - Published: 2014-01-23 - Granted: 2016-12-13 - Earliest claimed: 2012-07-17 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Rayoung Park; Yongjoo Yi; Woong Choi - Web page: https://patentgrep.com/patent/US9517949B2 ## CPC - C02F 1/44: by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)} - B01D 61/145: {Ultrafiltration} - B01D 61/147: {Microfiltration} - B01D 61/16: Feed pretreatment - B01D 61/22: Controlling or regulating - C02F 1/444: {by ultrafiltration or microfiltration} - C02F 1/5209: {Regulation methods for flocculation or precipitation} - B01D 2311/04: Specific process operations in the feed stream; Feed pretreatment - B01D 2311/2523: to feed side - B01D 2311/2642: Aggregation, sedimentation, flocculation, precipitation or coagulation - C02F 1/5281: {Installations for water purification using chemical agents} - C02F 2209/001: Upstream control, i.e. monitoring for predictive control - C02F 2209/11: Turbidity - C02F 2209/40: Liquid flow rate - C02F 2301/02: Fluid flow conditions - C02F 2301/046: Recirculation with an external loop - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract A water treatment apparatus and a water treatment method using the same are provided. The water treatment apparatus includes a cohesive agent input device configured to input a cohesive agent to raw water, a membrane filtering device, a raw water pump configured to transfer raw water including the cohesive agent therein to the membrane filtering device, a water supply flow path connecting a discharge side of the raw water pump to the inlet of the membrane filtering device, a circulation flow path connecting the raw water discharge opening of the membrane filtering device to the water supply flow path and a circulation pump provided in the circulation flow path to transfer discharged raw water to the water supply flow path. ## Claims ### Claim 1 A water treatment apparatus comprising: a cohesive agent input device configured to input a cohesive agent to raw water; a membrane filtering device including: an inlet configured to allow raw water including the cohesive agent therein to be introduced therethrough; a water treatment discharge opening configured to discharge treatment water to be discharged therethrough; and a raw water discharge opening configured to allow a partial amount of water which is not discharged as treatment water to be discharged therethrough; a raw water pump configured to transfer raw water including the cohesive agent therein to the membrane filtering device; a water supply flow path connecting a discharge side of the raw water pump to the inlet of the membrane filtering device; a circulation flow path connecting the raw water discharge opening of the membrane filtering device to a portion of the water supply flow path downstream of the raw water pump to supply the partial amount of water which is not discharged as treatment water downstream of the raw water pump; a positive displacement pump provided in the circulation flow path to transfer discharged raw water to the water supply flow path; at least one baffle formed to extend from an inner wall surface of the water supply flow path, and disposed at at least one of a right angle and a slanting angle with respect to a flow direction in the water supply flow path; and a valve installed at the water supply flow path to adjust an opening degree of the water supply flow path, and disposed downstream of the raw water pump to adjust a flow rate of raw water together with the baffle. ### Claim 2 (depends on 1) The water treatment apparatus of claim 1, further comprising a flow hampering unit configured to reduce a flow rate provided in the circulation flow path. ### Claim 3 (depends on 2) The water treatment apparatus of claim 2, wherein the flow hampering unit includes at least one baffle disposed at at least one of a right angle and a slanting angle with respect to a flow direction in the circulation flow path. ### Claim 4 (depends on 1) The water treatment apparatus of claim 1, further comprising: a contamination sensing unit configured to sense a degree of contamination of the raw water; and a control valve configured to open and close the circulation flow path such that a time during which raw water remains in the circulation flow path is controlled based on the sensed degree of contamination. ### Claim 5 (depends on 4) The water treatment apparatus of claim 4, wherein the control valve is disposed downstream of the positive displacement pump. ### Claim 6 (depends on 4) The water treatment apparatus of claim 4, further comprising: a raw water tank configured to store raw water; and a raw water supply flow path configured to connect the raw water tank to the raw water pump, whereby raw water is directly introduced from the raw water tank to the raw water pump. ### Claim 7 (depends on 6) The water treatment apparatus of claim 6, wherein the contamination sensing unit is provided at at least one of the raw water supply flow path and the water supply flow path. ### Claim 8 (depends on 1) The water treatment apparatus of claim 1, further comprising: a contamination sensing unit configured to sense a degree of contamination of the raw water; and a controller configured to control an operation of the positive displacement pump according to the sensed degree of contamination, wherein the controller is configured to control the positive displacement pump such that a flow rate of the discharged raw water to the circulation flow path increases as the sensed degree of contamination increases. ### Claim 9 (depends on 1) The water treatment apparatus of claim 1, wherein the cohesive agent input device is disposed upstream of the raw water pump. ### Claim 10 (depends on 9) The water treatment apparatus of claim 9, further comprising a contamination sensing unit configured to sense a degree of contamination of raw water, wherein an amount of cohesive agent input by the cohesive agent input device is determined based on the sensed degree of contamination. ### Claim 11 (depends on 1) The water treatment apparatus of claim 1, wherein the membrane filtering device includes a microfilter membrane. ### Claim 12 (depends on 1) A water treatment method of a water treatment apparatus of claim 1, the method comprising: applying a cohesive agent to raw water; supplying the raw water including the cohesive agent to the raw water pump; supplying the raw water including the cohesive agent discharged from the raw water pump to the membrane filtering device; extracting a partial amount of water which is not discharged as treatment water; and re-supplying the extracted partial amount of water to the discharge side flow path of the raw water pump. ### Claim 13 (depends on 12) The water treatment method of claim 12, further comprising sensing a degree of contamination of the water supplied to the raw water pump, wherein a time period for re-supplying the extracted partial amount of water to the discharge side flow path is determined according to the sensed degree of contamination. ### Claim 14 (depends on 12) The water treatment method of claim 12, further comprising sensing a degree of contamination of raw water supplied to the raw water pump, wherein the extracted partial amount of water is determined by the sensed degree of contamination. ### Claim 15 (depends on 12) The water treatment method of claim 12, further comprising sensing a degree of contamination of raw water supplied to the raw water pump, wherein an input amount of the cohesive agent and the extracted partial amount of water are determined according to the sensed degree of contamination. ### Claim 16 (depends on 15) The water treatment method of claim 15, wherein a flow rate of the raw water including the cohesive agent supplied to the membrane filtering device is determined according to the sensed degree of contamination. ### Claim 17 (depends on 16) The water treatment method of claim 16, wherein, when the measured recovery rate exceeds a first predetermined value, the input amount of cohesive agent and the extracted partial amount of water are decreased and, when the measured recovery rate is lower than a second predetermined value, the input amount of cohesive agent and the extracted partial amount of raw water are increased. ### Claim 18 (depends on 12) The water treatment method of claim 12, further comprising measuring a recovery rate from the membrane filtering device, wherein an input amount of the cohesive agent and the extracted partial amount of water are determined according to the measured recovery rate.