School me on inverted canisters in cold weather please…

[Jerry Adams]

Maybe if it's cold

But then your valve will become gummed up. And inverted mode is more twitchy. Maybe you lose a little fuel that's in the fuel line after you shut it off.

But the theory that inverted canisters gum up valves is just anecdotal

[David Thomas]

>"Then in an upright stove (which is probably 99% of users) it makes no sense to have any propane."

No, it helps throughout the canister's life, it just helps more in the beginning and less at the end. I suspect the missing data is this: The fractionation through distillation during vapor-feed isn't 100% perfect separation – not at all. It isn't that all the propane boils off and then the iso-butane and only then the n-butane. The first vapors are more propane-rich than average. The last vapors are propane-poor and N-butane-rich. Even with multi-stage distillation (those tall towers at oil refineries) operated at ideal-for-separation temperatures, the cuts wouldn't be perfect.

[David Thomas]

>"But then your valve will become gummed up."

This is an effect I haven't experienced (I don't have a ton of experience liquid-feed experience other than, of course, decades of white-gas burning. It may be that the specs for butane-mix canister is pretty lax on traces of heavier hydrocarbons. Normally, they'd mostly be left behind in the canister, but in liquid-feed mode (1) any such heavier hydrocarbons would go to the stove and (2) most liquid-feed stoves have a "vaporizer" section in the fuel line that is in the flame. At times, with hot flames, when the liquid has already flashed to vapor, that tube could get pretty hot. And hot petrochemicals can polymerize into bigger, heavier molecules – gums and varnishes that gunk things up. If that's the process, it would happen during extended high-output use.

> "And inverted mode is more twitchy."

Certainly if you use a vapor stove in liquid mode. If designed for liquid feed, they just didn't design a small enough valve.

> "Maybe you lose a little fuel that's in the fuel line after you shut it off.

Estimate: max of 40 cm of 2mm diameter tubing, (butane density of 0.6) = 1.3 ml = 0.75 grams of butane versus 227 or 454 grams per canister, so a loss of 0.3% each disconnect so maybe 5% loss of fuel if you have a lot of disconnects. Minimum estimate of 30 cm of 1 mm ID tubing = 0.14 grams – a truly small amount.

[Tad Englund]

David, I laughed out loud at your comments about the Hemisphere deferential.
Roger, I know get the mixed fuel thing- thanks
Stuart, thank for the info on the constant temps

I guess I wasn't paying too much attention during Physic and Chem 101, 37 years ago. I've had to "relearn" all that stuff over time from people like you guys.
I know make my own Bio-Diesel and kind of understand how to reconfigure carbon chains- or at least I get how to make Bio with out creating an emulsion (and if I do I know how to brake the emulsion) and as a by product, some powerful glycerin soap. Of course there the process of recapturing the Methanol but that's another issue. I guess I'll always have a large supply of Methanol for my alcohol stoves as long as I keep making the Bio.
How does this apply to stoves? I'm just trying to figure it all out- maybe by the time I die, I'll have a glimpse of what this whole thing is about.
Wow- that is too much this early in the morning. Sorry guys.

[Jerry Adams]

okay, okay,…

Roger said there was some white stuff on his valve

also said that it's important to be able to take your valve apart in the field and clean it

dohhh… that's because you're inverting your canister : )

I tried to take my valve apart at home and couldn't get it apart. There's this little pin. In the field it would be impossible. If I could get the pin out at home, it's not necesary so I would just leave it out and then it would be field maintainable.

maybe the white stuff is put in for some reason – lubrication or stabilizer or something

propane and butane are much more pure so you wouldn't expect higher weight molecules

white gas is a mixture of stuff that includes higher weight molecules. White gas stoves are sooty. And white gas stoves clog up so you have to be able to take them apart in the field. At least that's what I've had to do.

Canister stoves eliminate this – nice and simple – it seems like inverting takes away some of this simplicity

But, I've never used an inverted canister so that just makes me a troll…

[Stuart R]

It isn't that all the propane boils off and then the iso-butane and only then the n-butane. The first vapors are more propane-rich than average.

Very true. It is also true that the vapor from a full canister is propane rich regardless of the temperature. Or looking at it another way, the vapor will always contain some butane, no mater how cold it is.

Even with multi-stage distillation (those tall towers at oil refineries) operated at ideal-for-separation temperatures, the cuts wouldn't be perfect.

And so the gas in the canister is not even pure propane/butane to start with. For example, the MSDS for Coleman/Campingaz "Butane" canisters states that the composition is in compliance with French decree of 3/9/79 and has a boiling point of -5C (vs -0.5C for pure butane). In turn The Comite Francais du Butane et du Propane proscribes the properties of commercial Butane which it defines (in French) as "a mix of hydrocarbons made up mainly of butanes and butenes and containing less than 19% by volume of propane and propene".

This makes commercial sense of course: there is no need for a high purity fraction when the gas is only going to be burned in a camping stove!

[Roger Caffin]

> Then in an upright stove (which is probably 99% of users) it makes no sense to
> have any propane.
I can't see the logic here???

> The extra propane enables you to use the first part of the canister, but then
> you're stuck with a partially full canister with just butane that won't work.
True enough IF you are using the upright below freezing. Not true in the summer.

> Using iso-butane instead of regular butane is good.
Oh, very true. No problems there.

Cheers

[Roger Caffin]

> >"But then your valve will become gummed up."
> This is an effect I haven't experienced (I don't have a ton of experience
> liquid-feed experience other than, of course, decades of white-gas burning. It may
> be that the specs for butane-mix canister is pretty lax on traces of heavier
> hydrocarbons. Normally, they'd mostly be left behind in the canister, but in
> liquid-feed mode (1) any such heavier hydrocarbons would go to the stove and
>(2) most liquid-feed stoves have a "vaporizer" section in the fuel line that is in
> the flame.
I may be the source of the 'gummed up' information, as I have experienced it myself with a Whisperlite. I agree with David here: some gas sources may have looser specs on the presence of high molecular weight residuals. The Coleman Powermax canisters were wonderful: no residuals at all.

> > "And inverted mode is more twitchy."
This is a problem I hope to resolve in due course.

Cheers

[Jerry Adams]

"True enough IF you are using the upright below freezing. Not true in the summer."

In the summer when it's above freezing, upright works without problem, doesn't matter if there's propane.

The only issue is between 20 F and 30 F where iso-butane just barely works (or 30 to 40 F for n butane). Putting in a little propane makes the first half of the canister work better, but little difference as it gets towards empty.

If I used the first half of a canister at 20 F, then the last half when it was 30 F, the propane would be useful

[Roger Caffin]

> I tried to take my valve apart at home and couldn't get it apart. There's this
> little pin. In the field it would be impossible. If I could get the pin out at
> home, it's not necesary so I would just leave it out and then it would be field
> maintainable.
Correct on all counts. In fact, the issue of the pin was covered recently in another thread. Yes, you CAN press the pin out. It is only there to prevent you from unscrewing the needle completely while the stove is on the canister. I am sure the 'safety' people thought this was a huge improvement in safety, but I suspect they have never used a fuel stove of any sort, and would like to see them come in several colours.

> maybe the white stuff is put in for some reason – lubrication or stabilizer or something
> propane and butane are much more pure so you wouldn't expect higher weight molecules
Chuckle!!! In fact, ROTFLMAO!
Sorry, but …
The feed stock for our canister fuel is probably raw LPG from a gas well. That stuff contains everything, including water and dust. A fair bit of refining is required to get (clean up) the stuff we use.

Cheers

[Jerry Adams]

"I may be the source of the 'gummed up' information, as I have experienced it myself with a Whisperlite."

Yes, you are the source of my information : )

I don't remember anyone else reporting gummed up inverted stove valves, but I don't think there's a huge number of users.

[Tad Englund]

Our Scout troop learned a good lesson about this two weeks ago while camping with temps around 10*-15*.
By the time I got to the camp all of the uprights weren't working. The only stove working at the time was the Xtreme I had bought for the troop a few years back.
The boys and adults had tried to boil water for dinner and said that all the uprights ran out of fuel. I picked up one of the upright canisters and there was plenty of fuel in it (so much so, you could feel it when shaken).
We were able to have an impromptu lesson on winter stove use. I think this time they all were listening a little more- its a little difficult for 15 people to share only one working stove. Of course I had another Xtreme in my pack (my personal winter stove) but I they were getting on just fine without it (while learning).

I told them to save the canisters so they can use them during the summer.

[Jerry Adams]

"The feed stock for our canister fuel is probably raw LPG from a gas well. That stuff contains everything, including water and dust. A fair bit of refining is required to get (clean up) the stuff we use."

Isn't white gas worse?

White gas produces large amount of soot, the jet clogs up to the point that they include a little pin to unclog or there's an internal one that you just shake, I remember my stove getting clogged a couple times so I had to take it apart and eventually it started working.

I see very little soot on the bottom of my pan or the burner on my canister. I have used this hundreds of nights and never got clogged up. I used white gas stoves maybe 100 nights.

[Roger Caffin]

> Isn't white gas worse?
Well, one could argue either way.

IF the butane/propane mix has been prepared well to tight specs, then it can be fairly clean. White gas on the other hand is a very broad mix from the cracking tower – albeit perhaps more refined than autogas. In this case the canister fuel is more refined.

However, I have found Chinese canisters which were really dirty, so I suspect that they were a lot more careless, or less refined, in their preparation of the fuel. Compared to good white gas, the Chinese stuff was probably worse. But the Chinese stuff was significantly cheaper. I guess it was probably OK in an upright where you could strip and clean the stove easily.

Cheers

[David Thomas]

>"The feed stock for our canister fuel is probably raw LPG from a gas well. That stuff contains everything, including water and dust. A fair bit of refining is required to get (clean up) the stuff we use."

Here's an anecdote that Roger will follow and probably appreciate. The rest of you are welcome to ignore it.

I was abating extracted soil vapors in a "thermal combustion unit" – basically an over-grown burner but this particular one used soil vapors as combustion air in the flame. I was required to abate the emissions mostly because of the benzene is a "known human carcinogen". The compliance sampling results come back and there's not 98.5% destruction efficiency. Not at all. There's MORE benzene in the effluent than in the influent. I'm MAKING benzene, somehow! WTF? And, no, the samples weren't switched – I collected them myself.

Head scratching ensued, another trip to the site, analyzed the gross gases with a handheld meter, had an epiphany. I collected a sample of the NATURAL GAS (largely methane) and had it analyzed for benzene. There was more benzene in the fuel flow than in the effluent – I was destroying benzene after all. But the flame was very inefficient due to high CO2 (it was a toxic waste site) in the soil vapors.

Some years later, the utility (PG&E) was required to send notices to customers that their natural gas "contained chemicals known to the State of California to cause cancer. . . " and I thought, Yeah, and I know exactly how much is in there!

So if something you think of as C1 has some C6 (at a measurable concentration, therefore some heavier species as well), imagine what something sold as C3 (propane) or C4 (butane) has in it. Definitely some gasoline-range stuff and maybe some of the light end of diesel.

This stuff isn't sold as a laboratory reagent or pharmaceutical precursor. It's sold to be burned up.

[Jerry Adams]

"> Isn't white gas worse?
Well, one could argue either way."

No

I used Coleman white gas – fairly good quality I think, certainly the most common

I use Gigapower iso-butane/propane – not the most expensive (MSR) but pretty good

White gas was way dirtier

I did use some Burton (not Brunton) because I saw it at Fred Meyer's where it was cheap – n-butane/propane I assume – in upright mode and seemed to be just as clean – that would be your cheap Chinese

[Bob Gross]

I've seen white gas stoves that seemed to have a fuel problem. In at least two instances, it was Coleman white gasoline, and the fuel problems turned out to be clogging. When fully investigated, the clogs turned out to be solidified melted plastic. The plastic was from the plastic cap on the Coleman can, and it had gotten into the can, so it was poured into the Sigg fuel bottle that went on the trip. When the plastic flakes hit the heat of the stove, they melt and make the clog.

Suggestion: filter your fuel at least once between the Coleman can and the inner workings of the stove well before the burner jet.

For canister stoves, I don't have any problem with them as long as the fuel is within the expected temperature range.

–B.G.–

[Anonymous]

"Suggestion: filter your fuel at least once between the Coleman can and the inner workings of the stove well before the burner jet."

Used to be SOP when filling the fuel bottle.

[Bob Gross]

Yes, Tom. Lots of things like that used to be standard. Nowadays, nobody ever reads the instruction manual anyway.

–B.G.–

[Roger Caffin]

> Used to be SOP when filling the fuel bottle.
Coleman sells, or used to sell, a small yellow funnel with an inbuilt SS gauze strainer for that purpose.

Me, I used to filter the kero I was using through laboratory Whatman fibreglass filter papers using a vacuum pump! Still made a lot of soot though.

Cheers

[David Thomas]

Can I just say that I'm impressed by how much has been asked, answered, tweaked, and learned in this thread without it getting far afield nor the clueless jumping in to lead the blind?

Know what you know.

Know what you don't know.

Be ready to reconsider your assumptions and ideas.

Otherwise, forum discussion devolve to this:

http://xkcd.com/1166/

[Stuart R]

The knowledge of a handful of BPL members is this forums most valuable resource and this is the only reason that keeps me coming back.

I love your contributions David, your analogies of peach liquor distillation and oil fractioning towers (to name just a few) bring a wonderfully fresh perspective.

[Jerry Adams]

No, you're a MORON David : )

[David Thomas]

Thanks Jerry. . Takes me back to my days on Fine Homebuilding's forum when a discussion of liquid water at subfreezing temperatures due to a lack crystal nucleation sites had a belligerent contractor calling me all sorts of names because he was sure there was no atomic energy involved.

[Misfit Mystic]

Totally agree with Stuart's comment; the knowledge that is continually brought forth and subsequently archived on these forums is an invaluable resource. And Dave's comment about being intellectually honest and open-minded. It's what makes me such an ardent supporter of this community.

Sad that I must go online to find a large group of intellectually honest and open-minded folks. Outside of maybe college and university campuses, I don't really know where they exist anymore.

[Author]

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