Patents Assigned to Yoshihiko Ueda
  • Filter medium
    Patent number: 4708792
    Abstract: A filter medium comprising first and second filter mediums joined together. The first filter medium provides relatively large voids and has high porosity, while the second filter medium provides relatively small voids and has low porosity. Raw water is mainly introduced into the first filter medium, and water branching therefrom flows through the second filter medium, at which biological filtering is conducted by aerobic microorganisms breeding therein.
    Type: Grant
    Filed: April 21, 1986
    Date of Patent: November 24, 1987
    Assignees: Takara Kogyo Co., Ltd., Takashi Takarabe, Yoshihiko Ueda
    Inventors: Takashi Takarabe, Yoshihiko Ueda