Patents by Inventor Christian A. Keller

Christian A. Keller 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: 4544840
    Abstract: A generated signal is passed through an elongated signal conveying element positioned preferably perpendicular to the surface of a fluid the level of which is to be measured. The signal is directed from the signal conveying element to a detector element which senses the signal output from the signal conveying element. The signal output detected in an optical embodiment varies logarithmically with the depth of immersion of the signal conveying element into the fluid. A preferred embodiment employs an electromagnetic wave, e.g., light, signal which passes through a light pipe signal conveying element. By nearly matching the light pipe index of refraction with that of the fluid, a predetermined percentage of the wave is lost into the fluid each time the light is reflected further along the pipe.
    Type: Grant
    Filed: February 6, 1984
    Date of Patent: October 1, 1985
    Assignee: The Johns Hopkins University
    Inventor: Christian A. Keller
  • Patent number: 4443699
    Abstract: A generated signal is passed through an elongated signal conveying element positioned preferably perpendicular to the surface of a fluid the level of which is to be measured. The signal is directed from the signal conveying element to a detector element which senses the signal output from the signal conveying element. The signal output detected in an optical embodiment varies logarithmically with the depth of immersion of the signal conveying element into the fluid. A preferred embodiment employs an electromagnetic wave, e.g., light, signal which passes through a light pipe signal conveying element. By nearly matching the light pipe index of refraction with that of the fluid, a predetermined precentage of the wave is lost into the fluid each time the light is reflected further along the pipe.
    Type: Grant
    Filed: June 8, 1981
    Date of Patent: April 17, 1984
    Assignee: The Johns Hopkins University
    Inventor: Christian A. Keller
  • Patent number: 4319484
    Abstract: A generated signal is passed through an elongated signal conveying element positioned preferably perpendicular to the surface of a fluid the level of which is to be measured. The signal is directed from the signal conveying element to a detector element which senses the signal output from the signal conveying element. The signal output detected varies linearly with the depth of immersion of the signal conveying element into the fluid. In one embodiment, the signal conveying element is a capacitive probe comprising two plates or wires, one of which is grounded to the fluid into which the two plates or wires are immersed. Proper selection of accompanying circuitry results in detected signal changes which vary linearly with immersion changes. A second embodiment employs an electromagnetic wave, e.g. light, signal which passes through a light pipe signal conveying element. By nearly matching the light pipe index of refraction with that of the fluid, a predetermined percentage of the wave is lost into the fluid.
    Type: Grant
    Filed: August 31, 1979
    Date of Patent: March 16, 1982
    Assignee: The Johns-Hopkins University
    Inventor: Christian A. Keller