Patents by Inventor David M. Christianson

David M. Christianson 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).

  • Valve security guard
    Patent number: 6170306
    Abstract: A valve security guard is provided for a storage tank having a valve for dispensing material from the tank and includes a cover with a closed end and an interior with an open end for enclosing a valve handle, and a shaft member that extends through apertures in the cover that is lockable in a fixed position located behind the valve handle to secure the cover thereon.
    Type: Grant
    Filed: May 13, 1999
    Date of Patent: January 9, 2001
    Inventors: Dean E. Kitley, David M. Christianson