Propane pressure gauge

[Ralph Johnstone]

At the risk of flogging a dead horse:

But NO ONE has ever mentioned a float gauge before this point, not a whisper, not a mention, not so much as a mere thought. How can you say this horse has been flogged before ? A float gauge will react to a change in density as a function of temperature. A gravimetric scale reacts only to a change in mass. Nothing else.

We don't care if the liquid expands or contracts, if the liquid off gasses or the vapour partially condenses. We only thing we care about is the total, the full, the aggregate, the gross, the overall, the comprehensive, the unaltering mass of propane in the tank.

I think I'm spent. I'm overcome. BLAH !

 

[dlochner]

But NO ONE has ever mentioned a float gauge before this point, not a whisper, not a mention, not so much as a mere thought. How can you say this horse has been flogged before ? A float gauge will react to a change in density as a function of temperature. A gravimetric scale reacts only to a change in mass. Nothing else.

We don't care if the liquid expands or contracts, if the liquid off gasses or the vapour partially condenses. We only thing we care about is the total, the full, the aggregate, the gross, the overall, the comprehensive, the unaltering mass of propane in the tank.

I think I'm spent. I'm overcome. BLAH !

And this would be the reason I have a 6 pound tank, not a 1.5 gallon tank.

 

[Richard19068]

But NO ONE has ever mentioned a float gauge before this point, not a whisper, not a mention, not so much as a mere thought. How can you say this horse has been flogged before ? A float gauge will react to a change in density as a function of temperature. A gravimetric scale reacts only to a change in mass. Nothing else.

We don't care if the liquid expands or contracts, if the liquid off gasses or the vapour partially condenses. We only thing we care about is the total, the full, the aggregate, the gross, the overall, the comprehensive, the unaltering mass of propane in the tank.

I think I'm spent. I'm overcome. BLAH !

Ralph, I'm agreeing with you! I think that write up reinforces your point. It doesn't matter what the pressure or volume is. It's the weight (or "mass" if you prefer) that matters.

"the tank still has 424 pounds of propane. While the propane volume has dropped, the amount of propane has not decreases. It has simply become more compact, which means the amount of usable energy has not decreased"

 

[Johnb]

The main reason to have a pressure gauge to evaluate the integrity of the lines after the tank. With all the burners off, the tank valve open, open the solenoid and watch the pressure.

I am sure you meant to write "the tank valve closed". Otherwise the tank will just replenish what is lost in the leak.

 

[dlochner]

I am sure you meant to write "the tank valve closed". Otherwise the tank will just replenish what is lost in the leak.

Thank you, you are correct. It was post written in haste as my wife was waiting for me to go somewhere.

 

[LloydB]

I think his point was while the tank IS in use any weighing of it would be significantly inaccurate or overly complex. btw it looks like the float switch wouldn't work below -40 degrees Celsius either. I love this site where else can you get rocket science on a sailboat forum.

 

[Ralph Johnstone]

And this would be the reason I have a 6 pound tank, not a 1.5 gallon tank.

I cannot reply to carry on the virtuous battle as the virus (COVID that is) has overtaken me.

Carry on in the pursuit of truth, justice, or whatever the hell happens to float yer boat today !

 

[Ralph Johnstone]

And this would be the reason I have a 6 pound tank, not a 1.5 gallon tank.

Are those six imperial pound tanks or metric pound tanks ? It matters you know !

 

[kappykaplan]

the virus (COVID that is) has overtaken me.

Get well soon!

 

[Tally Ho]

What the gauge doesn't tell you is:

"WHO THE HELL FORGOT TO REFILL THE TANK LAST TIME THE BOAT WAS OUT"

I keep 2) 20 pound tanks at home for my gas grill, so when one runs out, we just switch it…

and I have 2) 10 pound tanks on the boat. 1 is always a full spare. I do use the spare for the bbq now and then but I know when I pull it out of the locker that it is mostly full.

I call that my 2-bin system… and I never run out.

Greg

 

[Ralph Johnstone]

where else can you get rocket science on a sailboat forum.

The rocket "science" is a little dubious at best. Rocket voodoo is a tad more descriptive.

 

[JamesG161]

All tanks are labelled with their MT and full weights.

Not here.

The Tanks are put on a scale and filled.

Weight difference is what you buy, thus the Temperature Compensation I mentioned.

Fill them when cold, you get more Propane.

Colder Canada

I now understand your Dark Tunnel.

Yes per E=MC^2

You have it correct, Ralph. Up closer to Santa for sure.
Jim...

 

[dlochner]

Not here.

The Tanks are put on a scale and filled.

That's what I thought until I had tanks filled in various parts of the East Coast. Some weigh, some measure gallons.

 

[Ralph Johnstone]

Not here.

I should have said I have labelled all three of my tanks only for my own estimation of Propane remaining in the tank.

Weight difference is what you buy,

Exactly what we do here in Canada but yours are in US pounds and ours are in metric pounds . We pay with metric dollars.

Fill them when cold, you get more Propane.

Nope, nope, and nope. You know how much it agrieves me to disagree with you BUT if you're buying propane by the gallon as per @dlochner, you want cold, cold, cold propane. Get it cold, heavy, and dense and you get more propane in a gallon.

If you're buying propane by the pound, get it hot, get it cold, it just doesn't matter. 5 pounds is five pounds no matter what you do.

And now Mr. JamesG161, for your final question worth $100,000.00,

WHICH IS HEAVIER, A POUND OF HOT PROPANE OR A POUND OF COLD PROPANE ?

You have thirty seconds to answer.

 

[JamesG161]

You have thirty seconds to answer.

I was watching a crime movie.
_____
It that a British Pound or USA Pound? Also the same weight of a Pound of Steam.
_____
And like I said, we WEIGH small tanks here, not by Volume.

I might find a Propane fill station soon to prove it by Pictures.

My whole house Generator uses Propane.

That 500 gallon tank is filled by Volume from a truck with 100 feet of hose.
It would difficult to weigh my tank.

Jim escapes again, from the clutches of the evil posters.

PS: Send my money with Santa.
PSS: Compressing a gas generates Heat.

 

[Ralph Johnstone]

Ralph, I'm agreeing with you! I think that write up reinforces your point. It doesn't matter what the pressure or volume is. It's the weight (or "mass" if you prefer) that matters.

Richard, my profound apologies here for my blunder yesterday. In my COVID inspired delerium yesterday, I thought it was @JamesG161 who had written the post on "flogging a dead horse" and of course figured he was using my COVID against me to get in a few last kicks while I was down. I was going to go after him for it even if I was down. Still, it was most un-neighbourly on his part even if he didn't write it , and I will be registering a protest with the race committee.

And @JamesG161 , I suppose an apology is in order (against my better judgement) for even thinking you would introduce volume as a measure of mass at that point in the discussion. Even though you were just "stickin' it to me !"

 

[smokey73]

I may be totally wrong, but as I recall, the "amount of liquid propane" can be deduced from observing the "temperature" at the tank surface. At the point of liquid level the temperature of the tank surface will be slightly below the temperature of the tank surface where the gas exists. (conductivity of the liquid is more than the gas) An old tank I used to have for my home grill had a strip of temperature sensitive material on the outside of the metal tank. At the level of the liquid propane the strip changed color if you doused it with a little water. Could you not use a non-contact temperature gun to see where the temperature changes on the surface of the tank. Just asking?

 

[Ralph Johnstone]

Exactly as you've said. Boiling liquid is cold but the gas is not cold or even if it was cold, poor conductivity. Get that tank surface below the dew point, and there's your liquid level. Crank up the grill fire to max. for 10-15 sec. and the liquid will cool very quickly.

Could you not use a non-contact temperature gun to see where the temperature changes on the surface of the tank.

Now that's just too, simple. If there's a significant temp. difference below the liquid line as compared to above it, the IR gun will see it as the liquid level.

The downside of that procedure is that it leaves nothing to bellow, and holler, beat one's chest, and ventilate one's lungs about what is the total mass of propane remaining in the tank and how best to measure it.

For that one reason, I cannot support the use of an IR gun to indicate the amount of propane remaining in a tank.

 

[Richard19068]

We pay with metric dollars.

And now Mr. JamesG161, for your final question worth $100,000.00,

WHICH IS HEAVIER, A POUND OF HOT PROPANE OR A POUND OF COLD PROPANE ?

You have thirty seconds to answer.

Cheech Marin, ... Ok, Bob, for 50 keys, What is your name? ... 30 seconds.
BOB: I know that one.

And hey, we pay in metric dollars too! Same as you. 100 cents to the dollar. And though ours are worth more you at least have the sense not to have cents for change filling up your coin tills and pockets.

Get well!

 

[JamesG161]

suppose an apology is in order

Apology Accepted.
I saw the switching back and forth between Weight and Pressure.

But enough info on the post to meet most boaters needs.
Jim...