Patents Assigned to Introtech, Inc.
  • Patent number: 5215378
    Abstract: A dual temperature indicator providing visual indications when exposed to predetermined high or low temperatures. The indicator has a bulb with a capillary tube and an attached high temperature indicator structure. The bulb has a first liquid which also fills a predetermined portion of the tube. A separating substance and a second miscible liquid further fills a predetermined portion of the remainder of the tube. At a predetermined low temperature, the liquid in the bulb contracts causing the separating substance and a portion of the second liquid to move into the bulb to produce a visible color change. The high temperature indicator structure has an indicating member in contact with the capillary tube end and which provides a visual indication at a predetermined high temperature when the liquids expand upon an environmental temperature increase.
    Type: Grant
    Filed: April 17, 1992
    Date of Patent: June 1, 1993
    Assignee: Introtech, Inc.
    Inventor: Wendell J. Manske