Fluid level indicator

Claim 1

A SENSING SYSTEM FOR INDICATING THE AMOUNT OF LIQUID WITHIN A CONTAINER, INCLUDING IN COMBINATION, DIRECT CURRENT VOLTAGE SUPPLY MEANS, AN ELECTRICAL INDICATING DEVICE FOR PRODUCING AN INDICATION WHICH VARIES WITH THE CURRENT APPLIED THERETO, AND A SENSOR DEVICE CONNECTED IN SERIES BETWEEN SAID VOLTAGE SUPPLY MEANS AND SAID INDICATING DEVICE, SAID SENSOR DEVICE INCLUDING FIRST AND SECOND CONDUCTORS AND A PLURALITY OF POSITIVE TEMPERATURE COEFFICIENT THERMISTORS ALIGNED TO BE DISPOSED AT DIFFERENT LEVELS WITHIN THE CONTAINER, SAID THERMISTORS BEING SELECTIVELY EXPOSEABLE AS THE LIQUID LEVEL WITHIN THE CONTAINER LOWERS SO THAT THE TEMPERATURE OF EACH EXPOSED THERMISTOR INCREASES, EACH OF SAID THERMISTORS BEING CONNECTED DIRECTLY BETWEEN SAID FIRST AND SECOND CONDUCTORS TO REDUCE CURRENT FLOW BETWEEN SAID CONDUCTORS AS THE RESISTANCE THEREOF INCREASES WITH INCREASE IN TEMPERATURE, SAID THERMISTORS PRESENTING A SUDDEN INCREASE IN RESISTANCE OVER A RELATIVELY NARROW TEMPERATURE RANGE, WHEREBY THE CURRENT PASSING THROUGH SAID SENSOR DEVICE TO SAID INDICATING DEVICE IS REDUCED.