# US 2014/0196419 A1 · Fan filter unit and air purification system for dust-free room > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0196419 A1 - Document ID: US20140196419A1 - Status: Published application - Kind: A1 - Application number: 13/807,221 - Filed: 2012-12-10 - Published: 2014-07-17 - Earliest claimed: 2012-10-30 - Assignees: Shenzhen China Star Optoelectronics Technology Co., Ltd. - Applicants: Shenzhen China Star Optoelectronics Technology Co., Ltd. - Inventors: Weibing Yang; Chunhao Wu; Kunhsien Lin; Yongqiang Wang; Zhiyou Shu; Minghu Qi; Zenghong Chen; Zhenhua Guo; Yunshao Jiang - Web page: https://patentgrep.com/patent/US20140196419A1 ## CPC - F24F 13/28: Arrangement or mounting of filters - F04D 29/703: {specially for fans, e.g. fan guards} - F24F 3/167: Clean rooms, i.e. enclosed spaces in which a uniform flow of filtered air is distributed (air distribution by perforated walls F24F7/10) - F24F 8/108: using dry filter elements - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) ## Abstract A fan filter unit (FFU) includes a fan, and a filter screen coupled with an air inlet of the fan. An air inlet of the filter screen is further configured with an auxiliary filter screen, and a minimum diameter of dust particles filtrated by the auxiliary filter screen is greater than a minimum diameter of the dust particles filtrated by the filter screen. ## Claims ### Claim 1 A fan filter unit (FFU), comprising: a fan; and a filter screen coupled with an air inlet of the fan; wherein an air inlet of the filter screen is further configured with an auxiliary filter screen, and a minimum diameter of dust particles filtrated by the auxiliary filter screen is greater than a minimum diameter of the dust particles filtrated by the filter screen. ### Claim 2 (depends on 1) The fan filter unit (FFU) of claim 1, wherein the auxiliary filter screen is fixed to an air inlet of the FFU by screw fixing or buckle fixing. ### Claim 3 An air purification system for a dust-free room, comprising: a factory; and fan filter units (FFUs) connected with the factory; wherein each of the FFUs comprises a fan, and a filter screen coupled with an air inlet of the fan; an air inlet of the filter screen is further configured with an auxiliary filter screen, and a minimum diameter of dust particles filtrated by the auxiliary filter screen is greater than a minimum diameter of the dust particles filtrated by the filter screen. ### Claim 4 (depends on 3) The air purification system for a dust-free room of claim 3, wherein an air outlet of each of the FFUs is connected to a top of the factory and an air inlet of each of the FFUs is connected to a floor of the factory. ### Claim 5 (depends on 3) The air purification system for a dust-free room of claim 3, wherein an air condensation layer is arranged between the filter screen and the auxiliary filter screen. ### Claim 6 (depends on 5) The air purification system for a dust-free room of claim 5, wherein an air outlet of each of the FFUs is connected to a top of the factory and an air inlet of the FFU is connected to a floor of the factory. ### Claim 7 (depends on 5) The air purification system for a dust-free room of claim 5, wherein the auxiliary filter screen is fixed to the air condensation layer by screw fixing or buckle fixing. ### Claim 8 (depends on 7) The air purification system for a dust-free room of claim 7, wherein an air outlet of each of the FFUs is connected to a top of the factory and an air inlet of each of the FFUs is connected to a floor of the factory. ### Claim 9 (depends on 7) The air purification system for a dust-free room of claim 7, wherein an air backflow filter layer is arranged between the air condensation layer and the filter screen. ### Claim 10 (depends on 9) The air purification system for a dust-free room of claim 9, wherein an air outlet of the each of the FFUs is connected to a top of the factory and an air inlet of each of the FFUs is connected to a floor of the factory. ### Claim 11 (depends on 9) The air purification system for a dust-free room of claim 9, wherein a temperature control ventilation layer is arranged between an air outlet of the factory and the FFUs and the auxiliary filter screen is arranged in the temperature control ventilation layer. ### Claim 12 (depends on 11) The air purification system for a dust-free room of claim 11, wherein an air outlet of each of the FFUs is connected to a top of the factory and an air inlet of each of the FFUs is connected to a floor of the factory. ### Claim 13 (depends on 11) The air purification system for a dust-free room of claim 11, wherein an air return duct is arranged between the temperature control ventilation layer and the air backflow filter layer, and airflow of the temperature control ventilation layer is communicated with airflow of the air backflow filter layer by the air return duct. ### Claim 14 (depends on 13) The air purification system for a dust-free room of claim 13, wherein an air outlet of each of the FFUs) is connected to a top of the factory, and an air inlet of each of the FFUs is connected to a floor of the factory. ### Claim 15 (depends on 13) The dust-free room air purification system of claim 13, wherein an air outlet of each of the FFUs is connected to a top of the factory and an air inlet of each of the FFUs is connected to a floor of the factory. ### Claim 16 (depends on 3) The air purification system for a dust-free room of claim 3, wherein an air outlet of each of the FFUs is connected to a top of the factory, and an air inlet of each of the FFUs is connected to a floor of the factory; a temperature control ventilation layer is arranged between an air outlet of the factory and the FFUs, and the auxiliary filter screen is arranged in the temperature control ventilation layer; an air condensation layer and an air backflow filter layer are arranged between the auxiliary filter screen and the filter screen in sequence, and the auxiliary filter screen is fixed to the air condensation layer by screw fixing or buckle fixing; an air return duct is arranged between the temperature control ventilation layer and the air backflow filter layer, and airflow of the temperature control ventilation layer is communicated with airflow of the air backflow filter layer by the air return duct; the auxiliary filter screen is configured to be removable.