Patents by Inventor Paul M. Hawkins

Paul M. Hawkins 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).

  • Sanitation indicator
    Patent number: 4353990
    Abstract: A device for monitoring thermal energy input and displaying the relationship of the thermal energy input to a selected time/temperature relationship. The device employs an indicating material which, when melted, expands and flows into a narrow channel to provide an irreversible, visible indication of the thermal energy to which the device has been exposed.
    Type: Grant
    Filed: February 9, 1981
    Date of Patent: October 12, 1982
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Wendell J. Manske, Paul M. Hawkins
  • Freeze indicating device
    Patent number: 4132186
    Abstract: A freeze indicating device which provides a visible record when it has been exposed to a specified low temperature such as 0.degree. C. The indicator utilizing a two-chamber, constant volume device, one chamber having a variable volume and another chamber being expandable upon freezing of an aqueous liquid therein. The expansion of the aqueous fluid transmitting pressure to the fluid in the variable volume chamber, thus forcing some of its fluid through a capillary passage onto a visible indicator.
    Type: Grant
    Filed: October 31, 1977
    Date of Patent: January 2, 1979
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Wendell J. Manske, Paul M. Hawkins