Patents by Inventor Douglas L. Lockhart

Douglas L. Lockhart 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).

  • Pressure measurement system for refrigeration system
    Patent number: 5311745
    Abstract: A pressure measuring system for a refrigeration system, such as a refrigeration system used in a commercial air conditioning system, comprises a converter (42) for converting a pressure being measured into a digital signal representing the measured pressure and a processor (54) for calculating a corresponding boiling point temperature for a selected refrigerant at the measured temperature. The system also includes a selector for selectively inputting the boiling point temperature-pressure relationship or coefficient of a selected refrigerant into the processor, as well as a display (60) for displaying the measured pressure and the calculated boiling point temperature.
    Type: Grant
    Filed: January 27, 1993
    Date of Patent: May 17, 1994
    Assignee: Digi-Cool Industries Ltd.
    Inventors: Douglas L. Lockhart, Oreste B. N. Varelas