Skip to content

Application Note

Hydraulic Oil Level Sensor Designed for Cement Grinding Mill

Hydraulic oil level sensor designed for cement grinding mill

Gill Sensors & Controls has designed and developed a custom heavy-duty hydraulic oil level sensor for installation on a new cement grinding roller mill prototype.

The sensor has been designed for heavy duty operation in the extremely harsh environment of the grinding wheel bearing housing, with a one-piece 316 stainless steel main construction and probe section with 5mm wall thickness.

The sensor is secured in place using eight M4 cap head screws, which are mounted via the eight 4.1mm diameter holes around the main mounting flange. An O-ring seal is positioned on the back face to seal around the cable outlet. The sensor also features a system of internal seals to allow the whole sensor to be sully submerged in oil, with environmental protection to IP68.

Mounted at an angle through the side wall of the reservoir, the sensor features five inlet/outlet holes on opposite sides of the sensing probe section to increase the responsiveness of the sensor to moving oil. The sensor is mounted with the inlet/outlet positioned vertically.

Along with an accurate indication of oil level in the reservoir, the customer requested that a temperature sensor is integrated into the probe to monitor and output oil temperature in real time. A PT1000 temperature sensor was subsequently designed into the wall of the main probe section at the tip of the sensor.


The sensor is designed for high temperature operation up to 125ºC, with the main probe section rated to 150ºC. The sensor is factory-calibrated to provide a 0.25V to 4.75V analogue output over the full 49mm measurement range.

Eight sensors have been manufactured and supplied for extensive testing on the first prototype cement grinding roller mill.

Hydraulic Oil Level Sensor Designed for Cement Grinding Mill