SENSOR CHOICES

Our Level Gauge can work with any sensor that provides a 4-20mA output. Sensors that can provide this output for sensing continuous level are: magneto-strictive, (float switch) capacitance, ultrasonic, RADAR, and pressure.  Of these  choices, the sensors we prefer are submersible pressure sensors, and RADAR.  (there are some others like optical sensors but they are completely unsuitable)

RADAR

RADAR sensors are non-contact and don’t require any intrusion into the process liquid. They are accurate to 1 mm and are not affected by dusts, vapors, foams, or turbulence. In fact they are sutiable for solids as well. They do have to be mounted with the internal tank structure in mind so stuctures in the tank don’t interfere. But with a narrow beam angle of 8º this isn’t usually a problem.

So why not ultrasonic sensors instead since they are cheaper?  The simple answer is that they are not reliable enough. Under perfect conditions they can work, but in real world tanks they are not reliable enough for us. We tested ultrasonics more than a decade ago and we have never sold them because they don’t meet our standards fo reliability. Here is some more information on the differences.

SUBMERSIBLE PRESSURE

Submersible level sensors (or hydrostatic sensors) determine liquid height by measuring the pressure on the sensor due to the weight of the liquid above it. This an established technology noted for its high reliability, low installation cost, and simple engineering. It is one of the most popular methods of liquid level measurement. Submersible level sensors may be used in almost all liquid media, from aggressive chemicals to pastes and sludges, providing reliable level measurement in the most challenging conditions.

Unlike ultrasonic sensors, submersible sensors are immune to turbulence, foam, fouling, obstructions. They don’t need to be tuned or calibrated, and they don’t need to be carefully positioned.  Finally, there is no “dead zone” to worry about.