Fluid level indicator

摘要

A low level indicator for a heated fluid in a container such as for use in indicating the glue level in a tank in a hot melt glue application. A thermistor probe is positioned at the mid-level of the container and senses the level of the heater fluid based upon sensing fluid contact with the probe. A light or alarm is activated when the heated fluid level falls below the probe, permitting of cooling the probe. The light or alarm is only activated when the probe becomes cooler subsequent to a time at which the probe was immersed in the fluid and properly heated. This conditional activation prevents continued low level alarm indications when the container is refilled with material at a temperature lower than that of the heated fluid.