Patents Assigned to Nitta Belting Co., Ltd.
  • Air filter assembly
    Patent number: 4323374
    Abstract: An air filter assembly including an electret filter sheet of material which exhibits electrical charges of opposite sign on opposite faces thereof and a non-electret conventional filter sheet of material combined with and disposed upstream from the electret filter sheet of material, whereby particles of a large diameter are collected by the non-electret filter sheet of material and particles of a small diameter are collected by the electret filter sheet of material without causing clogging or air pressure loss.
    Type: Grant
    Filed: October 19, 1979
    Date of Patent: April 6, 1982
    Assignee: Nitta Belting Co., Ltd.
    Inventors: Takehisa Shinagawa, Tsunehiko Inoue