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Jianaran
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Setting up a burner
Hi all,
I'm just starting to get into home chemistry, and one of the first things I want to do is set up a bunsen burner. However, we don't have gas where I
live, so I'd have to run it from a gas cylinder. This isn't a problem in and of itself, but before I start doing potentially dangerous things I'd like
to know what the best way to go about this is. The regulator attached to the LP Gas cylinder I have here claims to have a 2.75kPa output; is this a
useable pressure, or will I have to do something else to be able to attach a bunsen?
Also, if I'm going about this in entirely the wrong way, please feel free to point me in a better direction 
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watson.fawkes
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Quote: Originally posted by Jianaran  | | The regulator attached to the LP Gas cylinder I have here claims to have a 2.75kPa output; is this a useable pressure, or will I have to do something
else to be able to attach a bunsen? |
This is a standard low-pressure regulator for outdoor cooking grills.
So, does an outdoor grill put out enough heat for a 1L boiling flask? Yes it does.
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Jianaran
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OK, that's good to know. In that case, how would you advise taking the gas to a bunsen? Run some piping to a bench mounted tap, or go straight to the
bunsen and use the tap on the bottle to turn the flow on and off?
With regards to the pressure, I was actually worried that it might be too high. I'd imagine that an outdoor cooking grill probably goes through a lot
more gas than a bunsen, so could I have a dangerously high pressure leading up to the bunsen? 2.75kPa doesn't sound like much, but I really have no
experience with gas piping.
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bbartlog
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2.75kPa is in the same range as household natural gas - really pretty low pressure. Hooking it up directly to your bunsen burner should not be a
problem, though a bench mounted tap could be more convenient in the long run.
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Magpie
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Below is a picture of the setup I use for a bunsen burner. The regulator is something I picked up where BBQ supplies are sold. I don't know what
pressure it regulates to but sometimes I can't get the flame as small as I want.
Converting 2.75 kPa to units more familiar to me, that's 0.4 psi. That's probably about what mine produces too.
[Edited on 3-10-2010 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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Contrabasso
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There are some bunsen burner type torches available to screw onto some disposible gas cannisters in my area. Alternatively some small camping stoves
may suit your needs.
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spirocycle
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how long does that small canister last?
does it matter which gas is used?
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Magpie
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I don't know if you are refering to my post or the one after, but if mine:
The 1 lb propane cannister shown usually lasts me about 6 months. But I only use it for a minor part of my heating needs. Normally I use an electric
heating mantle or a hot oil bath.
I normally use propane. If I need more heat I have a 1lb MAPP cannister. I have recently aquired a Meeker burner for some serious flame heat.
The single most important condition for a successful synthesis is good mixing - Nicodem
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spirocycle
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excellent,
for only $2 a can, thats pretty sweet
the regulator didnt set you back too far did it?
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crazyboy
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I don't own a Bunsen burner and I never intend to purchase one. In my opinion open flames are a serious danger in a laboratory. For heating compounds
I use a hotplate or a heating mantle or is certain cases a power stripper. I realize you may not have money for these things but i seriously advise
getting one as an open flame could easily ignite solvent vapors, flammable solids, papers or other items in the lab.
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Magpie
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@spirocycle
IIRC the regulator was ~$15.
@crazyboy
I agree about not using an open flame around flammable solvents if at all possible. With ether I use a steam bath. But for some applications only a
flame will do, like heating a Thiele tube to get a melting point. A flame has the benefit of being able to be directed to a certain location. Also
it gives great control as you can remove it instantly if needed, or apply a lot of heat fast, if required.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Contrabasso
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A flame is one very valid heat source for a lab, there are several others! A careful risk assessment before you start a process should guide your
choices.
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MagicJigPipe
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Not to mention the fact that you can use it for various tasks around the lab/workshop, including but not limited to:
welding
glasswork
soldering/plumbing
high temperature reactions and dehydrations with a crucible (they still do experiments with Bunsens and crucibles at universities so it's not
completely obsolete)
cutting metals (with O2)
lighting cigarettes
smoking crack
burning waste gases
etc...
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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peach
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I use a propane torch at the moment, but will (after a long, long time without one) be picking up a bunsen sooner or later, as they're handy for
getting things moving quickly and inorganics.
I'm not sure if I'd recommend them for organic chemistry work. I have said in other threads how solvents aren't that much of a problem for me in terms
of fire, but that's partly because I'm always using them with a hotplate. With a bunsen, you have an excellent ignition source. Refluxing or boiling
off 100ml plus of solvent could potentially get bad with a bunsen.
I'm going to run mine off the natural gas line, since I helped the plumber (well, did most of his work for him) as we had our boiler fitted, so I've
seen what's okay as gas safe for the house.
The propane torch has one of those 600ml canisters on it. I see people heating things with flames waaaaaaay harder than they often need to be done.
Turn it up to get it warm, but you can then turn it right back down to almost off and just move the object close to the nozzle. Aluminium foil skirts
can help a lot.
I've kept things at 500C+ for 24h straight on one £3.50 can of propane.
If the cost of a hotplate is an issue (which it almost always is), nichrome wire is another option. That can be harvested from toasters from the tip
for free and will get hot enough to melt glass. Obviously, you need to be very careful if you're using it direct from the mains (having a transformer
between the two will float the voltage and isolate it, making it safer. You can control the temperature with a variac of coarse).
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1281371269
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I've just set myself up with a bunsen and a gas supply.
The bunsen is natural gas, the supply is butane. I had heard that you could overcome this with a regulator but the one I bought seems to have no
function for controlling the gas flow rate - either it is full on or it is off. At full on there is far too much gas coming out of the cannister (upon
lighting it I got a couple of foot high pillar of flame).
Do I need a new reg or a new burner?
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Contrabasso
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Better to get a matched pair, -same gas! The jets are different and the fuel air mix is different for those two gasses.
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1281371269
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Would that solve the glas flow problems then? Or do I need a new reg also?
To clarify with reg specs - it's the l/hr, not the pressure, that I'm concerned about, right?
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entropy51
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This regulator seems to be made for connecting a small propane cylinder to a Bunsen burner. I have not tried it myself.
I use the propane regulator from a Bernzomatic oxygen-propane torch. It appears to be just a simple needle valve and requires a little care to open
it just enough.
I have also just unscrewed the adjustment collar with the air inlet holes from a standard propane torch and attached a piece of tubing to the gas
orifice with a hose clamp.
Maybe I've just been lucky but I've never had any problems using any of several stray Bunsen burners from one of these small propane tanks without
regard to the type of gas the burner was designed for.
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peach
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I have one of those things as well, the twin cylinder sets that use disposable oxygen / fuel bottles?
The instructions sheet says it can be used for cutting, good luck with that!
But they are handy for getting super high temperatures without speaking to BOC or one of the others, and renting a gigantic cylinder set; capital cost
of the big cylinders and their low refill prices versus the ease and premium of the disposables.
The propane / butane thing is usually related to the size of the jet in the burner. I can use oxy/acetylene torches with propane without changing
much, but the flame from the acetylene sized tips doesn't give out as much heat if propane is run through, so they don't heat / cut properly. There
are different tips for propane, which are just bigger holes really.
I'd give it a go first and see if it'll work on the regulator you already have, because it probably will. Failing that, you can redrill the jet or buy
a replacement. Or grind the venturi's to a different size with the dremel.
If you don't have a regulator, try entropy's tubing from a gas torch suggestion. Or see if a neighbour has something you could try it with.
Bunsens are pretty forgiving things. Precise mixing becomes more of a problem when it's for welding, where the mix will chemically interact with the
metals.
Essential fire starting equipment, goggles optional
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1281371269
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I have found a cheap, workable solution to reducing the gas flow involving the rubber tubing and a bench clamp.
At some point I will make this a little more high tech with something like this:
http://cgi.ebay.co.uk/15mm-Gas-Lever-Valve-/320386661130?pt=...
It does appear that the natural gas bunsen isn't letting quite enough oxygen in, so a LPG one might be necessary at some point.
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Zinc
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Sorry for bringing up an old thread.
I have a teclu burner, which I belive is designed to work on natural gas(I am not 100% sure but when I conect it to a propane-butane cylinder I get a
huge luminous flame, if I reduce the gas flow too much it goes out, if I increase it too much it blows out).
So my question is how could I modify it to work on propane-butane? Is it the same as in modifying bunsen burners?
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IrC
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Jet size was mentioned but not really delved into much. Natural gas needs a metering jet three times larger in hole size as does propane. You must
reduce the jet size to one third as Bunsen burners are usually built with natural gas metering jets in mind. Going to 1/3 will put you back into the
BTU range the burner was designed for. Merely trying to control the pressure will not work properly. You waste fuel and do not reach the temperature
in the flame you should for the fuel consumption. IIRC 5 PSI is normal for natural gas. You need to have three things correct all at once for your
burner to work right. The metering jet, the gas pressure, the air inlet area. Hopefully you can locate the proper metering jet, with a diameter which
will give the BTU's desired while falling into the range of air flow adjustment the burner has by design. If you are good at working/drilling small
things, get a rod with an OD and length that will just tap into the jet. Flatten the ends with a file or Dremel first or drilling will be a bitch of a
job. Drill it with a hole 1/3 the diameter of the rod OD. Set your regulator to 5 PSI to start. Open the air a little. Light, adjust the air and
regulator pressure until the burner is working perfectly. This is a very easy conversion job. Those of you running now with setups you are playing
with gas pressure will see a great improvement in efficiency gaining much greater control. Obviously the BTU's VS fuel quantity are different, not to
mention the need to tailor the fuel/air ratio. If you have a CO2 meter you will also see a reduction in the pollution in your lab.
I should add if your jet can be unscrewed and is brass an easy method it to fill it with solder (properly heating the jet so good flow is obtained).
Then just drill a hole in the center of the solder of proper size. Less work and hopefully you are not ever going to get the whole burner so hot the
solder melts. If so you have things going on which should not be happening anyway. This is a hell of a lot simpler than making a rod fit a typically
3/32" hole. Plus a printed circuit drill bit is easy to find in the tiny size required. If you break it heat the jet, clean out the solder and broken
bit and start over with a new solder plug. Quick and simple but drill slowly, perfectly straight, with slight pressure.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Arthur Dent
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Your Teclu burner could be connected this way (see pix). I've used this setup for years (until I got a proper hotplate) but i was using propane
cylinders, I don't think a Butane/propane mix should be any different, the only caveat in this setup is the regulator knob is quite sensitive and
there's not much play between a 1 inch flame and a 1-foot flame. Be sure to turn the air-input ring to get the optimal flame you want. Does the Teclu
burner have such a ring?
Also, if you use this setup with PVC tubing, make sure to clamp both the gas bottle and the bunsen burner to avoid one or the other from falling on
its side.
Robert
--- Art is making something out of nothing and selling it. - Frank Zappa ---
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DrMario
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Sorry for bringing up an old thread (BTW, why is that even considered bad etiquette?) but I have a related question: I have purchased an old-school
Bunsen burner, in fact from Bunsen's homeland, and would like to feed it from a disposable gas bottle. This for safety and practicality reasons.
The problem is attachment: is there any adapter that would allow me to attach a standard hose with clamp to a disposable gas bottle? The gas bottles
I've seen sold have a small threaded valve. The only solution I see at this point, is to buy a portable gas burner and then just cut and throw away
the parts I don't need - which is most of them. That would cost me between 30 and 50 EUR. I'd prefer something cheaper and simpler.
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DrMario
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| Quote: Originally posted by DrMario | Sorry for bringing up an old thread (BTW, why is that even considered bad etiquette?) but I have a related question: I have purchased an old-school
Bunsen burner, in fact from Bunsen's homeland, and would like to feed it from a disposable gas bottle. This for safety and practicality reasons.
The problem is attachment: is there any adapter that would allow me to attach a standard hose with clamp to a disposable gas bottle? The gas bottles
I've seen sold have a small threaded valve. The only solution I see at this point, is to buy a portable gas burner and then just cut and throw away
the parts I don't need - which is most of them. That would cost me between 30 and 50 EUR. I'd prefer something cheaper and simpler.
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Potentially answering my own question (asking whether this is a good idea, actually): buy this and then hack off the burner part?
http://www.ebay.com/itm/Portable-Outdoor-Picnic-Gas-Burner-C...
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