Patents by Inventor Richard L. Duff

Richard L. Duff 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: 5868175
    Abstract: This disclosure relates to a vapor recovery unit of a fuel dispenser, and comprises a vapor pump, a variable speed electric motor coupled to drive the pump, and an electric control package connected to control the speed of the motor, the foregoing components being located in an integrated unit housing. The pump comprises a positive displacement vapor pump such as a vane pump; the motor comprises a variable speed induction motor; and the control package is operable to receive fuel-flow representative pulses from one or two flow meters, and to vary the pump-motor speed to recover substantially all of the displaced vapor during fueling. The unit housing is preferably installed in a dispenser cabinet and hydraulically coupled in a vapor flow pipe and electrically connected to receive the fuel flow pulses from one or two fuel flow meters. The vapor recovery unit is useful as original equipment (OEM) and/or as a retrofit component.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: February 9, 1999
    Assignee: Franklin Electric Co., Inc.
    Inventors: Richard L. Duff, Jim A. Beatty, Jason G. Awad