Patents by Inventor Douglas W. Francis

Douglas W. Francis 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).

  • Sprinkler system fertilizer injector
    Patent number: 6267303
    Abstract: A device for injecting liquid chemical solutions into the flow of a lawn sprinkler system. The device allows the user to easily attach and remove chemical jars without the risk of losing the prime on the pump.
    Type: Grant
    Filed: September 27, 1999
    Date of Patent: July 31, 2001
    Inventor: Douglas W. Francis
  • Ring
    Patent number: D513711
    Type: Grant
    Filed: January 26, 2004
    Date of Patent: January 24, 2006
    Inventor: Douglas W. Francis
  • Ring
    Patent number: D531537
    Type: Grant
    Filed: December 29, 2005
    Date of Patent: November 7, 2006
    Inventor: Douglas W. Francis
  • Ring
    Patent number: D531926
    Type: Grant
    Filed: December 29, 2005
    Date of Patent: November 14, 2006
    Inventor: Douglas W. Francis