So I'm tapping cans when ...

BigJohnny · Jul 28, 2015

I notice that the pressure is up to about 500PSI when the pumps high pressure switch cut them off.

So the tank has a 50.6Lb tare weight, and 92.5Lb Water Content weight.

80% of 92.5lbs is 74Lbs of tane.

so when full to 80% the tank would weigh 124.6Lbs

I stop my tapping and pull the tank out of it's freezer and weigh it... it weighs 107Lbs.

107.1Lbs - 50.6Lbs = 56.5Lbs of tane in the tank.

While it's out of the freezer and warming up I hear a hissing noise, only to find that the safety valve is starting to release pressure as it warms up.

Also if I crack the vapor valve liquid sprays out.
but I can see from the frostline, and the weight that the tank is well within it's safe limits and nowhere near full.

so why is the pressure so high?
why is the safety valve going off and releasing pressure as it warms up?
Why is liquid coming out of the vapor valve if I crack it open when the tank is only halfway full??

prune · Jul 28, 2015

your tank is about to explode, take it outside and vent the excess pressure!

(you forgot to figure in the fact that butane is not as dense as water, so it takes more space per equal weight)

BigJohnny · Jul 28, 2015

the tank is half full. there is literally half of the tank not full of liquid.

BigJohnny · Jul 28, 2015

Let's also not be overly dramatic here. I understand that butane is dangerous as fuck, but the tank isn't going to explode, that's why there is a safety valve. It'll pop and blow off pressure before the tank explodes.

prune · Jul 28, 2015

BigJohnny said:
the tank is half full. there is literally half of the tank not full of liquid.

so is your brain, vent the f'kn tank! :tiphat:

BigJohnny · Jul 28, 2015

Any chance you could provide an answer to the actual question as to why;

the tank is only half full but spewing liquid out of the vapor line if I open it. (this one being my biggest quandary)

the tank only has 56Lbs of tane in it but can hold up to 74Lbs and is still over pressurized

If not, then your suggestions of venting the tank aren't really telling me anything I don't already know.

prune · Jul 28, 2015

BigJohnny said:
Let's also not be overly dramatic here. I understand that butane is dangerous as fuck, but the tank isn't going to explode, that's why there is a safety valve. It'll pop and blow off pressure before the tank explodes.

Really? Overly Dramatic? You're trolling the internet with a fuming tank (extra-large for extry effect) of explosive gas in your shop and you're looking for competing solutions? You value $50 bucks of butane over everyone within shrapnel range of your ignorance?

Really, if you can't do the math or understand the physics - DON"T FILL THE TANK! (the prospective casualties will thank you)

prune · Jul 28, 2015

BigJohnny said:
Any chance you could provide an answer to the actual question as to why;

the tank is only half full but spewing liquid out of the vapor line if I open it. (this one being my biggest quandary)

the tank only has 56Lbs of tane in it but can hold up to 74Lbs and is still over pressurized

If not, then your suggestions of venting the tank aren't really telling me anything I don't already know.

Dufus, vent the BOMB and argue the science later!

BigJohnny · Jul 28, 2015

prune said:
Really? Overly Dramatic? You're trolling the internet with a fuming tank (extra-large for extry effect) of explosive gas in your shop and you're looking for competing solutions? You value $50 bucks of butane over everyone within shrapnel range of your ignorance?

Really, if you can't do the math or understand the physics - DON"T FILL THE TANK! (the prospective casualties will thank you)

is there something wrong with you? I did the math, I've been doing the math for over a year now filling this same tank.

I'm not asking wtf to do, I'm trying to figure out why the fuck it's happening.

all of the math says that it shouldn't be happening, all of my previous experience doing this countless times says it shouldn't be happening as I have had the tank more full than it currently is now.

I'm asking for an explanation as to why this occurring so I can learn from it and figure out how to avoid this problem in the future.
the pressure gauges tell me that it's within safe limits (the gauges could be bad sure, but they've been accurate until today)
the frostline tells me that the tank is physically half full.
the weight tells me that the tank is well within it's limits.

the actual measurements and weights tell me that everything should be ok.... but it is not.

so why is it not? that's what I want to know..... not that I should vent the f'kn tank which is something that I already know and have done.

so, can you answer the question(s) or are you just going to continue spewing shit?

Avinash.miles · Jul 28, 2015

Rickys bong · Jul 28, 2015

BigJohnny said:
I notice that the pressure is up to about 500PSI when the pumps high pressure switch cut them off.

So the tank has a 50.6Lb tare weight, and 92.5Lb Water Content weight.

80% of 92.5lbs is 74Lbs of tane.

so when full to 80% the tank would weigh 124.6Lbs

I stop my tapping and pull the tank out of it's freezer and weigh it... it weighs 107Lbs.

107.1Lbs - 50.6Lbs = 56.5Lbs of tane in the tank.

Prune already said it but I'll try to make it more clear.

You state your tank has a 92.5lb. water capacity.

THAT IS NOT THE BUTANE CAPACITY.

Butane weighs 0.604 times what water weighs.

92.5*0.604=55.9 lbs

The butane capacity of your tank is somewhere around 56lbs.
It should be filled with no more than 45lbs of butane. Canned butane is also some percentage of propane, which is even lighter.

Your tank is completely full. The frostline has zero relevance in this case. The only time the frostline will indicate level is when you are withdrawing vapor from the tank and the liquid contents are below zero degrees.

You are lucky the safety valve is not a burst disc as the entire contents of the tank would have vented....

RB

BigJohnny · Jul 28, 2015

the tank is sitting at ~50PSI according to measurements from 3 different gauges. 350PSI below it's safe limits.

it still weighs 56Lbs.

It's still only ~1/2 full.

It's still spewing liquid out the vapor line...... explain please.

BigJohnny · Jul 28, 2015

Rickys bong said:
Prune already said it but I'll try to make it more clear.

You state your tank has a 92.5lb. water capacity.

THAT IS NOT THE BUTANE CAPACITY.

Butane weighs 0.604 times what water weighs.

92.5*0.604=55.9 lbs

The butane capacity of your tank is somewhere around 56lbs.
It should be filled with no more than 45lbs of butane. Canned butane is also some percentage of propane, which is even lighter.

Your tank is completely full. The frostline has zero relevance in this case. The only time the frostline will indicate level is when you are withdrawing vapor from the tank and the liquid contents are below zero degrees.

You are lucky the safety valve is not a burst disc as the entire contents of the tank would have vented....

RB

ffs. thank you.

we keep it in a freezer so it's around -17F.

I've read much, and everything I've seen says 80% fill even with butane, even on this site.

not one post that I've seen has mentioned that 55Lbs would be max fill for butane.

so you're telling me that physically my tank is full to the brim with liquid?

If that's the case then why is(was) the frost line in the middle of the tank if there's no vapor space above the liquid?

GratefulOne · Jul 28, 2015

WOW!!!! Just WOW!!!! Super scary stuff here. Guys this is basic level 1 stuff. If you can't make these calculations you really are no where ready to be running a flammable solvent.

92.5 lb WCW - 20% = 74 lb of water

74 / 8.34 lbs per gallon = 8.87 gallon of usable space

8.87 gallon * 4.86 lbs per gallon (butane) = 43.12 lbs of butane max

43.12 + 50.6 tare weight = 93.7 lbs total tank weight when full of butane

Trying to over fill the tank by nearly 31 POUNDS!!!!!!!! Come on guys stop trying to do this stuff until you spend the effort to learn.

Why do the guys who show up asking these level 1 questions always end up saying they are "experts with tons of experience"? They are so quick to get aggressive anytime they are told anything other than what they want to hear. Learn what you are doing - your experience is crap if you are asking this question. People at this skill and attitude level are the biggest problem to extractor's future.

Rickys bong · Jul 28, 2015

Yes, I'm telling you the tank is physically completely full. The frostline has no relation to level in this case and you should never ignore the weight of the tank.

Was the tank on its side in the freezer? If there is a "frostline" then in this case its maybe an indication that not all of the liquid in the tank has cooled below zero C. As you were adding butane some of the contents hadn't cooled down yet.

Not knowing that butane and water have completely different densities is a major oops.

Like I said, if the tank had a burst disc rather than a safety valve you'd have a much larger problem on your hands.

RB

BigJohnny · Jul 28, 2015

GratefulOne said:
WOW!!!! Just WOW!!!! Super scary stuff here. Guys this is basic level 1 stuff. If you can't make these calculations you really are no where ready to be running a flammable solvent.

92.5 lb WCW - 20% = 74 lb of water

74 / 8.34 lbs per gallon = 8.87 gallon of usable space

8.87 gallon * 4.86 lbs per gallon (butane) = 43.12 lbs of butane max

43.12 + 50.6 tare weight = 93.7 lbs total tank weight when full of butane

Trying to over fill the tank by nearly 31 POUNDS!!!!!!!! Come on guys stop trying to do this stuff until you spend the effort to learn.

Why do the guys who show up asking these level 1 questions always end up saying they are "experts with tons of experience"? They are so quick to get aggressive anytime they are told anything other than what they want to hear. Learn what you are doing - your experience is crap if you are asking this question. People at this skill and attitude level are the biggest problem to extractor's future.

Look man, I'm not a newb, but this is the first time I've seen an actual number on the density of tane. I've had the tank at 50Lbs before without issue or anything even close to this happening.

This isn't a matter of being an idiot and only wanting to hear what I want to hear, I came here asking a legitimate question looking for an educated answer and didn't get that. I just got the generic "vent the tank" which is something I already knew and did, until the pressure was well within it's safe limits.

I did a lot of searching and reading before even attempting to fill this tank over a year ago and not once did I come across any mention of butane density. I knew it wasn't the same as water, but everyones answer came down to the same thing, 80% of the WC value is how much tane you put in the tank.

Rickys bong said:
Yes, I'm telling you the tank is physically completely full. The frostline has no relation to level in this case and you should never ignore the weight of the tank.

Was the tank on its side in the freezer? If there is a "frostline" then in this case its maybe an indication that not all of the liquid in the tank has cooled below zero C. As you were adding butane some of the contents hadn't cooled down yet.

Not knowing that butane and water have completely different densities is a major oops.

Like I said, if the tank had a burst disc rather than a safety valve you'd have a much larger problem on your hands.

RB

you sir, have done absolutely nothing but provide quality answers with the math and numbers to back it up.

And I thank the powers that be that we don't have a burst disc valve, because that would be beyond catastrophic.

The tank isn't on it's side, but once again you provide an answer with an explanation about the frost line.

despite how much of an idiot you may think I am, I appreciate that you can and have provided the answers to the questions I was asking. I have a far greater understanding now than I did an hour ago.

GratefulOne · Jul 28, 2015

Also- keeping tanks in a freezer has already caused fires. The valves can not handle the cold temps and start to leak. The freezer then fills with flammable vapors. Opening the door creates sparks that will ignite the fuel.

Also the metal starts to get brittle the colder you go. These tanks are not rated for super cold temps. Check limits from tank maker.

BigJohnny · Jul 28, 2015

GratefulOne said:
Also- keeping tanks in a freezer has already caused fires. The valves can not handle the cold temps and start to leak. The freezer then fills with flammable vapors. Opening the door creates sparks that will ignite the fuel.

Also the metal starts to get brittle the colder you go. These tanks are not rated for super cold temps. Check limits from tank maker.

Previously the temp hasn't been an issue, and our robinair tank has been absolutely amazing in terms of valve shrinkage at our temps, I've kept an eye out for this since out mastercool tank went bad.

HOWEVER, this was with a system of doing work for 4 days, every other week.

With what we were doing we had a perfect balance in freezer temp and time needed to cool.... if that makes sense.

When we would start on a monday the tank would be at just the perfect temp to not cause any issues at all. and when we were done on thursday afternoon the tank and freezer had achieved an equilibrium that would take the other 10 days to get back to the optimal temp for our schedule.

now that we've slowed down and the tank has sat for up to two weeks without use it has caused it to become much much colder and I've started to notice the valves will puff tane sometimes when it's between full open and full closed.

so indeed, re-adjustments and precautions are necessary.

GratefulOne · Jul 28, 2015

Having done something many times does not make you an expert. Getting lucky doing it wrong is not a indication of your knowledge.

Pointing to doing it wrong as proof of experience proves the point your knowledge is not ready.

Not understanding density is scary but that can be learned. Not finding it important through research shows a lack of effort or ability in research.

Having attitude that you are an expert when you ask this kind of question is the scary part. Please understand your knowledge level for all safety issues is likely way too low if you asked this question in the first place. Just because you don't like the answer does not mean it is wrong.

If someone taught a cls safety class - how to weight solvent would be the first lesson. This is the level you are on. It does not matter how many times you have done it wrong. Please understand there are things you don't know and understand- They matter! If experts say you are being scary with safety then please listen.

GratefulOne · Jul 28, 2015

Robinair does not make tanks- they are Manchester tanks with a Robinair label. Check the stamps in the metal.

Again- multiple fires have been confirmed by people putting tanks in a freezer.

Best of luck. Please take this stuff more serious. Your knowledge and attitude of experience are dangerous.

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