×

Thermal level detector for conductive or nonconductive liquids or gases

  • US 4,638,288 A
  • Filed: 03/22/1982
  • Issued: 01/20/1987
  • Est. Priority Date: 03/22/1982
  • Status: Expired due to Term
First Claim
Patent Images

1. A monitoring system comprising:

  • a thermistor (13) having a turnover temperature, said thermistor assuming a predetermined resistance when the temperature of said thermistor is above said turnover temperature;

    means (15) for thermally coupling said thermistor to a liquid in a vessel when the level of said liquid is above a predetermined level, said liquid lowering the temperature of said thermistor below said turnover temperature when thermally coupled thereto;

    means (10) for thermally insulating said coupling means from said vessel;

    a tone generator (45, 59, 60, 70, 71, 79-90) for sounding a plurality of warning signals;

    a warning circuit (9, 11, 12, 14,

         15) directly connected to said thermistor and electrically isolated from said liquid for generating one of said warning signals indicating that the level of said liquid is below said predetermined level when said thermistor assumes said predetermined resistance; and

    an annunciator (61-65, 67-69) for displaying said one warning signal.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×