Can Ultrasonic Sensors Accurately Measure Gas Tank Levels?

[LD300316]

Hi Folks,

I am exploring using Ultrasonic for LGP tank level measurement. I went through lots of readings, in particular use of SRF02 sensor. But, It's not conclusive.

Anyone has been exposed to solving such problem? If yes, kindly share return on your experience.
Appreciate!

 

[berkeman]

Hi Folks,

I am exploring using Ultrasonic for LGP tank level measurement. I went through lots of readings, in particular use of SRF02 sensor. But, It's not conclusive.

Anyone has been exposed to solving such problem? If yes, kindly share return on your experience.
Appreciate!

Welcome to the PF.

Are these external sensors? Hopefully you're not trying to home-brew a sensor that you will insert into the tank...

 

[LD300316]

Indeed, external sensor that would be placed ideally at the bottom of the tank.
Looking for the type of Ultrasonic sensors that would be suited for such applications, frequency, formulas for measuring the gas level.

 

[jrmichler]

Is this LP gas? In theory, an ultrasonic sensor mounted externally should work.

The Adafruit sensor has a minimum sensing range in air of 15 cm. The minimum range in a liquid will be farther by the ratio of the speed of sound in the liquid to the speed of sound in air. The Adafruit sensor is designed to measure the distance from the sensor to the nearest hard object - the outside surface of the tank.

The challenge is to find a sensor that directly couples to the metal tank, and has a minimum sensing range less than the minimum tank level. It needs to ignore the interface between the tank and the liquid, detect the interface between the liquid and gas, and ignore the interface between the gas and the tank.

The nondestructive testing (NDT) people use ultrasonic sensors to find small defects in steel over small distances. Their sensors are certainly capable of doing what you want. Their electronics would be overkill. You could study how they do it, and look for something simpler and cheaper.

 

[Tom.G]

The usual non-electronic method is a strip of liquid crystal thermometer tape applied vertically to the outside of the tank. This senses the temperature difference between the liquid and gaseous states.

If you need electronic sensing then load cells to weigh the tank is common.

Perhaps you could find a linear-tape form of resistive temperature sensor in place of the liquid crystal thermometer approach. Might need compensation for ambient temperature swings.

Let us know what you find that works for you. (we like to learn too!)

Cheers,
Tom

 

[dlgoff]

Is this LP gas? In theory, an ultrasonic sensor mounted externally should work.

Since I use propane as a heating source, I got curious about this. I did a little searching and found this site showing Generac makes a top of tank Wi-Fi level monitor. Here's a screen-shot from the installation .pdf file:

 

[LD300316]

Thank you folks for your reactions...
- jrmichler - yes, LP gas. More specifically, Butane tank of 20, 30, ... KG. I'll look at Adafruit sensors.
- Tom.G - Strip, I saw that Technic but I prefer to explore different and more sophisticated ways. I looked in the past to load cell approach, but It may not fit as requires more logistics to consider, compared to light sensor way...
-dlgoff - what's the site you are referring to?

Thanks

 

[hutchphd]

If you wanted to calibrate it you might be able to detect the resonant response freguency as the level. Is there always a meniscus for the various gases (ie are we below the triple point) ?