Patents by Inventor Craig C. Walden

Craig C. Walden 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).

  • Fish rearing system
    Patent number: 4043299
    Abstract: A fish rearing system. Water is recycled from a fish rearing tank to a primary filter. Ammoniacal nitrogen load is reduced by rapid removal of nitrogenous solids. The water is formed through a biological filter containing a particulate medium of small particle size. Prior removal of solids prevents filter blockage. The filter is provided with backwash means that include an air scour. The water is reaerated after the filter and returned to the fish rearing tank.
    Type: Grant
    Filed: May 1, 1975
    Date of Patent: August 23, 1977
    Assignee: British Columbia Research Council
    Inventors: Alexander E. Birkbeck, Craig C. Walden