Patents by Inventor Walter C. McMahan

Walter C. McMahan 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).

  • Patent number: 4412447
    Abstract: An inverted tube closely fits a supporting cup and contains a column of water. A substantially annular or ring-like space is formed between the cup and the tube. Water is fed to the annular space through a lateral opening in the tube, the upper edge of the opening being located just below the level of the cup rim. As water evaporates from the exposed ring of water, it is replaced by the inverted column, air being admitted through the tube opening. Evaporation and transpiration causes reduction of the water level thus to indicate the amount of moisture loss from the surrounding soil.
    Type: Grant
    Filed: July 23, 1981
    Date of Patent: November 1, 1983
    Inventor: Walter C. McMahan
  • Patent number: 4169386
    Abstract: A water pressure gauge for agricultural use comprises no moving parts. A translucent tube has one end provided with a hollow prong or probe that penetrates flexible water conduit. The tube is open at the end opposite the probe and has an outlet opening located near the probe end. With the guage vertically oriented, water reaches a level in the tube dependent upon water pressure. By careful calibration of the outlet relative to an interior baffle, a reasonably satisfactory water pressure gauge is available for irrigation purposes.
    Type: Grant
    Filed: February 8, 1978
    Date of Patent: October 2, 1979
    Inventor: Walter C. McMahan