Patents by Inventor Melvin D. Campbell

Melvin D. Campbell 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).

  • Apparatus for in-situ calibration of instruments that measure fluid depth
    Patent number: 5277054
    Abstract: The present invention provides a method and apparatus for in-situ calibration of distance measuring equipment. The method comprises obtaining a first distance measurement in a first location, then obtaining at least one other distance measurement in at least one other location of a precisely known distance from the first location, and calculating a calibration constant. The method is applied specifically to calculating a calibration constant for obtaining fluid level and embodied in an apparatus using a pressure transducer and a spacer of precisely known length. The calibration constant is used to calculate the depth of a fluid from subsequent single pressure measurements at any submerged position.
    Type: Grant
    Filed: December 23, 1991
    Date of Patent: January 11, 1994
    Assignee: Battelle Memorial Institute
    Inventor: Melvin D. Campbell
  • Tensiometer with removable wick
    Patent number: 5103654
    Abstract: The present invention relates to improvements in tensiometers for measuring soil water tension comprising a rod shaped wick. the rod shaped wick is shoestring, rolled paper towel, rolled glass microfiber filter, or solid ceramic. The rod shaped wick is secured to the tensiometer by a cone washer and a threaded fitting.
    Type: Grant
    Filed: October 11, 1990
    Date of Patent: April 14, 1992
    Assignee: Battelle Memorial Institute
    Inventors: Glendon W. Gee, Melvin D. Campbell