Having the "donor" cannister above and upside down dowes help transfer more fluid, but once the pressures equalize, that's all that will transfer. Butane, propane etc all work by the pressure exterted by the gas as it turns from liquid to gas. That gaseous stage forces whatever materiaql thru the nozzle to the empty tank or stove burner or... If the butane cannister is right side up, the top portion of the can is filled with gas, not liquid, and so the gas is what transfers and quickly equalizes pressure in the recipient can. Like the other guy said, you will quickly fill the empty can with fumes and thaqt is all you will get and burn time will be short. You need to transfer fluid since there it is far denser and "energy rich" than the gaseous state. So like I said once pressure equalize that is it. You may be able to use multiple "donor" cans and get more fuel into the refil, but eventually there will be a point of dimishing returns and you won't be able to overcome the pressure built up in the refilled can. Thus you need a pressure relief to allow more fuel to be let in due to diminished pressure in the tank fighting the incoming fuel. That is why you see the relief valve on all the heavy propane cans. P1V1=P2V2. In our case, Volumes may vary due to can size so Pressure is the only varfiable that matters to us. You can play with pressure by heating or cooling cans but in the end you are limited by pressure available from the donor, versus pressure built up in the refil. Ah, memories of Thermodynamics 101. Jim Henderson
Hi Ron I bought something like this from Hong Kong. Not on UK ebay at the moment but come up regularly by seller plus2city. I used the cartridge adapter and hose. The Globe Trotter nipple has an M6x0.75 thread. Handily the hose also terminated in a male thread of the same size so I just used an "O" ring to seal it and was sorted. Another adapter I have made from a M10x1.0 brake union threaded internally with M6x0.75 to take the hose and with a 15mm AF nut silver soldered onto it. This adapter fits some of the other Gaz stoves including the one that screws onto the refillable cylinders 901,904 and 907. Hope this helps.
Hi Gary, actually I bought a hose that connects to the camping gaz canister from plus2city and I only used the contol that screws on to the canister and connected it to my stove hose. I noticed the rubber hose they used underneath the braided sheath was very thin that it would easily get punctured by the braided line if it ever got cut. So instead used my stove hose which has a 1.2mm skin thickness much safer IMHO. Ron
Absolutely correct, Jim, but recall that some of the butane will be in liquid form. All of the liquid butane will flow down into the lower canister and all of the gaseous will bubble up into the upper canister. Of course P1V1 = P2V2, but that only applies to the gaseous butane. With all of the liquid flowing into the lower canister the total amount of butane (gas + liquid) will be greater in the lower canister. I don't know that the lower canister will be at 100% but it will certainly be more than a 50 - 50 split between the two containers in terms of total amount of butane. HJ
I would think that the only way to maximize transfer would be to vacuum the contents of the receiving canister prior to filling it up with the donor canister as am sure that there is residual pressure in the recipient tank which is equal to the outside pressure hence when connected to a lit stove the flames just die out once pressure is equalized. Just like in the automotive a/c mechanics first vacuum the unit before adding freon. Ron
Don't know that the "air" in the bottom refil tank will bubble up into the donor tank. I suppose some might make it up, but the contest is between unequal pressures forcing fluid flow from hi to low pressure. Definitely will get fluid flow downwards but my experience with refilling Propane tanks is that no matter how long you let the "air" bubble up to the donor tank, you rarely get anywhere near 80% or there abouts, thus again the reason for the relief valve. This was the reason I experimented with the relief valve way back, plus putting 2 and 2 together for ideas from the instructions on my refillable Paulin tank kit. You can clearly hear the gas transfer. On an unvented tank it slows down rapidly to no sound and wild guess is the tank is 50% or so full. If you crack open the relief valve, you can hear rapid gas transfer again. So at least my experience is there is no significant bubbling up with propane refills. However, refilling cigarette lighters with butane, does seem to work to almost 100%, you have to try several times and shake the bubble around and have a pretty full donor, but it can be done. So perhaps I am wrong or just need to shake the propane bulk tank around? But I have seen a mist from the better brand lighters which might suggest a built in venting mechanism? The refill nipple on the better lighters does appear to be spring loaded. I even have a small butane stove with built in clear plastic tank that is a pita to refill more than say 70-80% from the spraypaint can butane. Shake and jiggle and full donor might get me there, but a real pain. As a historical note, my Paulin brand refillable propane set came with an officially refillable cylinder. I purchased it I believe in the early 80s before "save the idiot user" became popular. The cylinder has a relief valve that is openable with a common wrench, it is a reverse schrader valve with a nut to loosen it. The instructions state clearly to crack open the relief valve to maximize filling of the tank, stop when white mist appears. So even Paulin knew you couldn't get enough refil transfer without relieving the pressure. I always wondered how the more modern sets that do not include a refillable cylinder would hope to attain significantly more than 50%-60% filling. Maybe it is a safety "Feature" to prevent lumoxes like me from blowing themselves up with over full refills. I wonder if I am overanalyzing this. And almost all my experience is with propane. So maybe I am comparing apples to oranges. Jim Henderson
Jim, Ah, now that you've walked through the steps a bit more, what you're saying makes a lot of sense. Actual experience speaks far more loudly than my conjecture. I'll have to try it with actual butane canisters if I really want to know. HJ
I have a butane refillable 'picnic stove' that has the same valve as a lighter. It fills to about 80% (known by weight change). With that, you get a certain amount in but until you go to remove the refil canister ( and it vents), you wont get more in. Try again and she fills up. Alan
Hey Gary, the reason I asked is because I am more interested on how you were able to mate the tube to the burner assembly. Did you use the original jet or you mentioned a male nut threaded on the outside to screw on like the jet? I hope I am making sense here so I included a picture with a circle. I have pretty much a donor globetrotter and for this purpose to supply gas to a separate (non-camping gaz) burner connected to each other by a rubber hose. I could then slip on one end of the rubber hose to the camping gas assembly (the one circled in yellow) via the protruding brass tube as pictured. I could not find the right thread here on this side of the pond to work on. Ron
Ron I unscrewed the globetrotters nipple to check the threads to make an adapter but found that the nipple was M6x0.75 Which was luckily the same thread as on the end of the hose. No other modification was necessary (other than slipping on an "O"ring). I hope this helps.
Thanks Gary, must go to the car junk shop and find a foreign or british made car and see if I can find a brake nut similar to that so I can use it.
This Jananese site has adapters... http://www.noanohakobune.netfirms.com/ Just use google translate. translation
Anyone in the other side of the pond willing to get me 1 or 2 pcs of M6x0.75 brake nut. Will pay for postage and cost please. Just want to see if I can make it work with my camping gaz. Thanks in advance. Ron
Hi I may have created some confusion. Here are some photos that may make sense of what I tried (badly) to put into words. This is my refilling rig for Camping Gaz 901, 904, 907 cylindrs using a stove designed for those cylinders (legs removed coz they get in the way). This is the adapter unscrewed from the stove, it's a M10x1.0 brake pipe nut with a larger nut soldered on and internally threaded M6x0.75. Disassembled from the hose showing the two different connections. Hope this helps.
Hi Gary, no confusion on my part. Just wanted to get the specs on the nut n thread that went into the CG in place of the nipple. And as Baja suggested, I will try the brake shops to see if they carry the item. Ron
Ah, I see. I don't think we have that kind of canister her. What product number is it? What size is it? We have CV206, CV270, CV360, and CV470 canisters here in the US. I have not seen any of the CGnnnn, CPnnn, or Rnnn series containers here in the US. HJ
