gas volume sensor

is there a sensor to measure gas volume in cylinder that's compatible with arduino?

The volume of a gas always expands/compresses to fill the volume of the container...

[u]Pv = RT[/u].

Could this be another go at measuring the amount of liquid propane in a tank by measuring gas pressure?
We had several of them in the past months.
Leo..

Wawa:
Could this be another go at measuring the amount of liquid propane in a tank by measuring gas pressure?
We had several of them in the past months.
Leo..

There should be a sticky at the top of the forum for subjects we are tired of seeing.

Paul

biremee24:
is there a sensor to measure gas volume in cylinder that's compatible with arduino?

Possibly an ultrasonic ping sensor could do but maybe not inside of a tank. You'd have to try.

Where do you get cylinders that are compatible with Arduino? What would make a cylinder non-compatible?

biremee24:
is there a sensor to measure gas volume in cylinder...

The volume of gas in a cylinder with a constant volume is always the same.

But maybe not in the US, where gas could be a liquid.
Leo..

Hi,
If its LPG (Propane) it will be liquid in the tank, measure volume by mass.

Gas pressure is constant no matter how much liquid is present in the tank.
The pressure gauges you can get calibrated in tank volume, only start to show a drop in pressure when the tank becomes almost empty.

Tom... :slight_smile:

Even if liquid the volume of the container is not going to change (much - there is of course thermal expansion and the pressure of the contents, which also changes with temperature and may drop to zero when completely empty).

Would it work by measuring weight/mass? Measure a full bottle and empty bottle and set your scale. I am sure I have seen someone using scales before

Yes, weight is an easy way to tell how much liquid propane is in the bottle.
People that fill the bottles put them on scales.
Full and emply weight should be stamped on the bottle.
Leo..

A propane tank will soak heat wherever liquid propane is against the side. Pour warm water down the side and it should show you where the inside has liquid propane.

wvmarle:
Even if liquid the volume of the container is not going to change (much - there is of course thermal expansion and the pressure of the contents, which also changes with temperature and may drop to zero when completely empty).

Completely empty means what? Normally a propane tank is "empty" when the pressure is zero. But it is still full of propane gas at atmospheric pressure. To empty the propane bottle completely and replace the propane gas with air, the bottle must be opened and turned up side down so the propane will flow out. It is heavier than air. This takes several days.

Paul

Sorry for being ambiguous. I meant empty as in pressure equal to outside pressure - which would be called "empty" for most practical purposes. Not pulled vacuum which would be the closes to truly empty, and even that's a matter of debate due to vacuum having some "dark energy" or so - anyway even if the propane is replaced with air it's not completely empty :slight_smile:

Anyway it's indeed hard to take this too serious as it's been up so often over the past months, and many people apparently don't know how to or don't bother to search on the topic.

OP: yes weighing is the way to go. The easiest, most accurate way of measuring how much propane you have in the tank.

GoForSmoke:
A propane tank will soak heat wherever liquid propane is against the side. Pour warm water down the side and it should show you where the inside has liquid propane.

Even more pronounced when you are using the gas, the evaporation of liquid to gas absorbs energy, so the gas/liquid interface is noticeably cooler.
Tom... :slight_smile:

Paul_KD7HB:
Completely empty means what? Normally a propane tank is "empty" when the pressure is zero. But it is still full of propane gas at atmospheric pressure. To empty the propane bottle completely and replace the propane gas with air, the bottle must be opened and turned up side down so the propane will flow out. It is heavier than air. This takes several days.

Paul

Fill the tank with water then pour that out.