Can Ultrasonic Sensors Accurately Measure Gas Tank Levels?

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Discussion Overview

The discussion revolves around the use of ultrasonic sensors for measuring the levels of liquefied petroleum gas (LPG) in tanks, specifically focusing on the SRF02 sensor and other potential methods for accurate measurement. Participants explore various approaches, challenges, and experiences related to this application.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants inquire about the feasibility of using ultrasonic sensors, particularly the SRF02, for measuring LPG tank levels, noting that existing readings are inconclusive.
  • One participant confirms that the sensor would be mounted externally at the bottom of the tank and seeks recommendations for suitable ultrasonic sensors, including frequency and measurement formulas.
  • Another participant suggests that while ultrasonic sensors theoretically could work, they highlight challenges such as minimum sensing range and the need for the sensor to differentiate between the gas and liquid interfaces.
  • Alternative methods are proposed, including the use of liquid crystal thermometer tape and load cells for weighing the tank, with one participant expressing a preference for more sophisticated electronic sensing methods over traditional approaches.
  • A participant mentions a specific product, a Wi-Fi level monitor by Generac, which may provide insights into practical applications.
  • There is a suggestion to explore the calibration of ultrasonic sensors by detecting resonant response frequencies and questioning the presence of a meniscus for various gases.

Areas of Agreement / Disagreement

Participants express a mix of curiosity and skepticism regarding the effectiveness of ultrasonic sensors for this application. While some agree on the theoretical possibility, others raise concerns about practical challenges and alternative methods, indicating that multiple competing views remain.

Contextual Notes

Participants discuss the limitations of ultrasonic sensors, including minimum sensing ranges and the need for sensors to accurately detect interfaces between different states of matter. There are also unresolved considerations regarding the calibration and operational conditions of the sensors.

Who May Find This Useful

This discussion may be of interest to individuals exploring sensor technologies for measuring liquid levels in tanks, particularly in the context of LPG applications, as well as those looking for alternative measurement methods.

LD300316
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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!
 
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LD300316 said:
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. :smile:

Are these external sensors? Hopefully you're not trying to home-brew a sensor that you will insert into the tank...
 
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.
 
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Likes   Reactions: berkeman
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.
 
  • Informative
Likes   Reactions: berkeman
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
 
jrmichler said:
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:

LPG tank sensor.jpg
 
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
 
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) ?
 

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