Viscous Liquid Level Alarm

Capacitive liquid level sensor

This is a custom alarm for a customer to alarm when epoxy resin level in containers gets too low. 

With the 10,000cp resin means there will be a residue of resin clinging to the sensor tip for a long time before it runs away.  This  residue must be ignored for a reasonably fast alarm response. Calibrating the alarm perfectly was a challenge for this unit.


This unit measures under 10mm in diameter, and mounts using a 1/4″NPT cord grip. This particular sensor is run from 24V power, although could just as easily be powered from any source of other line power like 12VDC.  There is a 15A relay output available.

The sensor pipe is chemical-grade PVC.  PVC enclosure is rated IP65.


There is a silencing button to silence the buzzer. After silencing, the LED continues to flash for 30 minutes and then the buzzer sounds again every 30 minutes if the condition is not corrected. Everything reset automatically when the level is corrected.

This type of sensor would be useful for any viscous liquid like honey, corn syrup, slurries.