Patents Assigned to William B. Darwin
  • Hydroponic system convertible to an open or closed system
    Patent number: 4021964
    Abstract: A new and improved hydroponic system including a plant supporting chamber having an inert, supportive medium therein; a collection reservoir positioned below the plant supporting chamber; a pump reservoir for containing a nutrient solution and delivering the nutrient solution to the plant supporting chamber and first and second valve means for operating the hydroponic system as either a closed or an open hydroponic system as desired.
    Type: Grant
    Filed: February 11, 1976
    Date of Patent: May 10, 1977
    Assignee: William B. Darwin
    Inventors: William B. Darwin, Joseph Michael Livengood