Patents by Inventor Aaro Ahlgren

Aaro Ahlgren has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5051195
    Abstract: Method and equipment for filtration of a suspension so that the suspension to be filtered is fed from a feed part (4) onto the filter face of a filter member (5), which moves relative the feed part. The pulp layer is formed on the outer face of the filter member and the filtrate flows into the interior of the filter member, and the pulp layer is removed from the filter member at the removing point. After the pulp removing point (17), before the feed point (4), one or several cleaning points (12) are provided wherein liquid is made to flow through the filter member (5) from the inner face of the filter member to the outer face. The flow rate of the liquid that flows through the cleaning point or points is adjusted higher than the rate of any liquid flow that may flow through the rest of the filter member from the inside-face side to the outside-face side.
    Type: Grant
    Filed: October 13, 1989
    Date of Patent: September 24, 1991
    Assignee: Sunds Defibrator Rauma Oy
    Inventors: Pertti Haapamaki, Aaro Ahlgren, Lassi Suoninen, Juho Eriksson
  • Patent number: 4995988
    Abstract: Method and drum filter for thickening of slurry and for treatment of the slurry with liquid. The slurry to be thickened is passed onto the filter face of a drum (3) revolving in a basin (3), and the treatment liquid is passed through the pulp web formed on the drum. The consistency of the pulp web is increased by pressing a compression plate (10) against the pulp web. The compression force of the compression plate (10) is produced by means of the pressure of a liquid and/or gas passed to the convex side of the plate. The compression force can be adjusted by adjusting the pressure prevailing in the gas space outside the drum (3).
    Type: Grant
    Filed: December 14, 1988
    Date of Patent: February 26, 1991
    Assignee: Sunds Defibrator Rauma Oy
    Inventor: Aaro Ahlgren