I need to measure the liquid level of LPG through a thick 4000/8000/45000 stationary tank. They already have flowmeters but they are easily tampered. I need to be able to know how much Gas is in the tank (1% tolerance). I found some ultrasonic sensors Online that are designed to work with thick LPG tanks (at least they say) but they do not answer my emails and I was not able to source them.
Does anyone have experience with these sensors? Does anyone know of a sensor that works for such tanks?
If there is some other tamper proof method I could also use that. The floater sensing method is easily tampered so it's not an option.