Patents by Inventor David A. Neilsen

David A. Neilsen 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).

  • Method and apparatus for separating gravel from bark and for cleaning fines from both the bark and the gravel
    Patent number: 5224605
    Abstract: A method and apparatus for separating bark from gravel including first and second conveyors disposed within a trough having a first zone and a second zone maintained preferably at different liquid levels by virtue of a partition dam to provide cleansing of the bark and the gravel so that these substances have commercial vitality apart from each other.
    Type: Grant
    Filed: February 15, 1991
    Date of Patent: July 6, 1993
    Inventor: David A. Neilsen