Gems Sensors Non-Contact Radar Level Sensor in Hydraulic Units


Hydraulic Power Units (HPUs) consist of an engine (gas or diesel) or an electric motor that pumps hydraulic fluid to a component to power it.  The flow and pressure of the hydraulic fluid can drive motors, pumps, cylinders, jack hammers, cutting saws, and numerous other hydraulic powered systems.  It is a closed loop system so the hydraulic fluid will be pumped from the reservoir on the HPU out to the component needing the fluid through one hydraulic hose and then return to the HPU on a second hose.  Maintaining proper hydraulic fluid level is critical to the efficient operation of a Hydraulic Power Unit. 


Challenge:  Finding a cost-effective, easily configurable non-contact level sensor that can handle the low dielectric of Hydraulic Oil.


Solution: Gems Sensors Non-Contact Radar Level Sensor

The Gems Sensors’ radar level sensor is a non-contact continuous level transmitter.  Radar technology works by sending out short microwave signals toward the liquid via the sensor.  The microwave signal then hits the liquid surface and bounces back toward the sensor.  The sensor utilizes the time-of-flight principle which uses the known speed of the microwave, and the time it took for the signal to return, divided by two (since it had to travel down to the liquid and then back up to the sensor) to determine the distance between the liquid level and the sensor.  Since most level is based on the height of the liquid, not the height of the non-liquid (air), the air height is subtracted from the total tank depth to determine the liquid level!

Gems Sensors  non-contact radar sensor is a great fit for Hydraulic Power Units for several reasons.  With an Ingress Protection rating of 68, it can be installed in high moisture environments with no risk of moisture intrusion.  The radar sensor is constructed of PVDF which is resistant to corrosion and is not affected from harmful UV light exposure.  With a 2” NPT mounting it has a standard mounting that will be compatible with most tanks found on HPUs.   

A key benefit of is its ability to be configured to any tank ranging from 1 foot up to 49 feet.  This allows the use of one type of level sensor and use it on all the different tank depths they without having to source multiple sensors.  Previously with a float and stem-based level sensor, you would need a specific sensor for each tank depth.  Submersible pressure sensors are another option, but you need to worry about chemical compatibility of the cable and sensor head.  These also require calibration adjustments between different types of hydraulic oils specific gravities.  The non-contact radar level sensor does not need adjustment when used with different hydraulic oils and its non-contact design eliminates the need to worry about chemical compatibility.  With a maximum process temperature rating of 80 degrees Celsius and full vacuum to 43 PSI rating, it can withstand extreme applications.


Below are additional benefits of Gems Sensors Non-Contact Radar Level Sensor:   

  • Comes standard with Bluetooth® configuration/setup.  This saves sourcing and inventory costs as it reduces inventory management from multiple specific transmitters for each different tank depth down to one!
  • Gems’ radar sensor is a compact design which helps reduce expensive shipping costs and transit times. 
  • Non-contact design means no media ever comes in contact with the Radar sensor.  This eliminates the need to worry about material compatibility between the media and sensor components. 
  • The non-contact design is by default a no moving parts solution, which eliminates the potential for any mechanical failures from a float or probe-based sensor. 
  • Radar through the air technology is a very accurate sensing technology and can detect liquid level within 5mm, with no effect on its accuracy based on changes in temperature or pressure. 
  • Radar technology is not affected by condensation or dust in the air like ultra-sonic based sensors.  


The above characteristics make Gems Sensors' radar sensor an ideal solution to work in Hydraulic Power Units.  With standard outputs including 4-20mA, and Modbus, it is compatible with almost any type of controller or display.  Gems Sensors’ radar sensor also has built-in Bluetooth® capability for simple configuration.  During setup it has the ability to sense obstructions within the beam angle and ignore them.  This increases the potential installation areas as there is no need to work around tank obstructions like pipes or other sensors.  This helps save countless installation man hours and eliminates the need to make costly tank modifications.      

Gems Sensors Radar Level Sensor is an excellent match for Hydraulic Power Units.     


 Additional Sensors:

  • XT-800 medium float level transmitter
  • XT-700 small float level transmitter