Sub-millimeter filter tube pore diameter determining method and sub-millimeter filter tube pore diameter determining device

The invention provides a sub-millimeter filter tube pore diameter determining method and a sub-millimeter filter tube pore diameter determining device. A particle interception method is adopted. When mixed liquid containing particles permeates through a sub-millimeter filter tube, whether the particles can be intercepted is determined by the relative size between the diameter of pores of the sub-millimeter filter tube and the diameter of the particles, and the particles can pass through pores with the diameter being greater than that of the particles and are intercepted by pores with the diameter being smaller than that of the particles. The pore aperture of the sub-millimeter filter tube is measured in the mixed liquid by determining the rate of interception of the sub-millimeter filter tube to a series of particles of different and known diameters. The determining device is a fully mixing device. The mixed liquid is stirred to make the particles mixed and uniformly distributed in the mixed liquid, a sub-mil