Non water base liquid level detection/measurment


Thread Starter


I have problem in finding an instrument to detect/measure non water base luquids, eg oil, disel, aviation fuel. Can anyone help, thanking
you in advance for any advise.

Steve Myres, PE

If the liquid is dense enough, try a mercury float switch from Mercury Displacement Industries. If the index of refraction of the liquid is suitable, you can try the transparent cone type optical level sensors, supplied by Gems or Omron. I've also used a capacitive proximity switch in a sealed plastic pipe, sticking down into the solution (close off the bottom of the pipe and the prox sits face down on the flat bottom). The pipe has to be plastic or it will activate the switch. The solution that I did this to was water based, but I think it would work for your type liquids as well, though. There are also some float switches available for low specific gravity liquids, as well.

Steve Myres, PE
[email protected]
Barton Inst. LLC -City of Industry CA/USA has a guided radar tank topmount level measuring system that works in refined fuel.
if you are detecting fluid level in a tank, you could use a "sonitrol" type sensor. several manufactures make this type sensor including sonitrol. they send an audio signal to bounce off the liquid and measure the delay like radar.
any wave action can cause an error.

capicitive prox sensors from your favorite prox sensor manufacturer can detect non-ferrous material like liquids, plastics and paper but they must be close to the material. usualy the sencitivity is adjustible.

if you are detecting a flammable liquid your application may require a special sensor so that any failure mode of the sensor dosen't cause a spark.

your local electrical supply house should be able to help you find the proper sensor for your application. i often rely on sales teams to educate me about products i may need fir an application.

hope this helps
Tim Davis

Matt Warshawsky

If you need to detect the presence and quantity of these compounds in large amounts I would think that an float level sensor or float switch would work. I've used them for detecting hydrocarbon tainted water in a natural gas / hydrogen / oxygen stream (a highly flammable environment!).

If you need to identify the presence of small quantities, I would use a gaseous hydrocarbon sensor (for example GasTech, Inc.) and place it in the space above where you expect the compounds. These have pretty quick response and usually output a voltage or current proportional to concentration as well. They are pretty sensitive though since they are designed for detecting concentrations below the lower explosion limit.

To detect between different hydrocarbons, you will probably need to use a GC, though others may know of better ways.

Verhappen, Ian

You should be able to use pretty well anything other than Capacitance.

For instance:
Differential Pressure Head
Ultrasonic Level
Radar Level

Just go with what you are most comfortable with and meets the requirements versus your budget.

Ian Verhappen
Syncrude Canada Ltd.