Patent ID: 6217281
Filing Date: 2001-04-17
Classification: F04D

Abstract:
A low-noise fan-filter unit for providing filtered air into a clean room, comprising:a rectangular hollow housing having an air inlet formed on a first wall thereof and an air outlet formed on a second wall opposite to said first wall, side walls being provided between the first and second walls;a fan, installed in said housing and near said air inlet, for drawing air through said air inlet into said housing;a filter, installed in said housing and positioned between said fan and said air outlet, for removing impurities from the air flowing through said housing;a flow-guiding plate, installed in said housing and positioned under said fan, for turning the direction of said air drawn through said inlet, the flow-guiding plate having a top surface and a bottom surface and the flow-guiding plate having a curvy extension formed around an edge thereof, the curvy extension being on the top surface of the flow-guiding plates facing the fan, the curvy extension terminating before the bottom surface of the flow-guiding plate with edges at ends of the curvy extension being vertical and generally parallel to at least one of the side walls of the housing;a noise-reduction plate unit having a first plate portion and a second plate portion respectively, installed in said housing and positioned between said flow-guiding plate and said filter, so as to form a tortuous air passageway among said flow-guiding plate, noise-reduction plate and said filter; andsound-absorbing materials furnished along said air passageway for reducing the noise of the air flowing through said passageway.