Patent ID: 11141686

Abstract:
A hollow cylindrical depth filter formed of fibers of a thermoplastic resin and having a thickness of a filter medium of 5 to 25 millimeters, in which the filter medium has a compression ratio of 0.2 or less when a load of 0.5 MPa is applied thereto, the filter medium has a fiber layer of at least three layers from a fluid inflow side toward an outflow side, porosity of the three layers are adjusted to a specific range, respectively, and intersection points of the fibers forming the filter medium are bonded, a mean interval between the intersection points is 2 to 100 times a mean fiber diameter of the fibers in a length direction, and a ratio of the mean fiber diameter on a surface on an upstream side to the mean fiber diameter on a surface on a downstream side of the filter medium is 0.9 to 1.2.