Sciencemadness Discussion Board

What's wrong with my bunsen burner?

LiveWire - 31-1-2006 at 04:16

I recently spent a lot of cash on some glassware and apparatus.. I'm now not only broke, but in debt as well!

One thing that's really upset me is the bunsen burner I've gotten. For some reason, I can't get a nice pretty two-cone flame from it. I get a really tall blue flame, but there's no real inner cone, just an outline of a really big white cone a millimeter or two from where the blue flame ends. See the attached picture.

So what's wrong here? I tried a lot of ways to improve it: The air holes are relatively small, so I thought maybe there isn't enough air and tried pumping air into it with an aquarium pump, but that just blew the blame up and made it worse.. I also put a pice of aluminum foil with holes in it over the hole in the top, but that didn't work either. Oh, and increasing the gas flow just makes the flame taller.

Is there any way I can make the flame better? With my current flame, I can't even bend a glass pipe, unless it's really really thin, and in that case I can do it faster on the stove!

Thanks!

P.S. I'm new here.. Great forum you got going!

bunsen_flame.jpg - 10kB

joeflsts - 31-1-2006 at 04:23

Are you using natural or bottled gas? Also, which type of burner did you get? A natural gas burner will not work well with bottled gas.

LiveWire - 31-1-2006 at 04:37

I'm using gas from a pipe in the wall! (The same as the stove, water heater, etc.) That would be natural gas, wouldn't it?

I don't know what kind of burner I got, I just went into the store and picked up a burner; I didn't know it mattered! Would it help if I attached a picture?

joeflsts - 31-1-2006 at 05:23

You might check with the store you bought it at. It sounds like you have a bottled/LP burner and your source is natural gas. I'm guessing but I suspect that is the problem.

crankyperson - 31-1-2006 at 08:52

i would say,that there's not enough oxygen to get a good flame.maybe you should check whether there's some dirt in your burner!

Esplosivo - 31-1-2006 at 08:58

Quote:
Originally posted by crankyperson
i would say,that there's not enough oxygen to get a good flame.maybe you should check whether there's some dirt in your burner!


That is what I was thinking too. I leave my bunsen burner outside, summer and winter, and you might imagine the dust and things which clog it up (it's cheap and I don't really care too much about it). Sometimes a similar thing happens to me too. My immediate solution is to open the gas and clean it with some volatile organic solvent, say methanol, ethanol or DCM (the gas is not ignited). More often than not, after ignition, the flame immediately restores to normal. When it does not it usually turns to normal after leaving it burning for 30 minutes. Can't say how this works, but it works for me. Hope this helps.

[Edited on 31-1-2006 by Esplosivo]

garage chemist - 31-1-2006 at 09:02

Check for what sort of gas the burner is made. Burners for natural gas cannot be used for propane and vice- versa.
If you can't find it out, try running it with propane and see if it burns better.

It could also be possible that the gas nozzle is partially plugged, by corrosion or dirt that fell into the burner (happened to my burner several times, very hard to clean!)

If there is no visible damage to the air inflow, it gets enough oxygen. It must be one of the reasons I outlined above.

vulture - 31-1-2006 at 12:53

Quote:
Check for what sort of gas the burner is made. Burners for natural gas cannot be used for propane and vice- versa.


Odd. I use a Teclu burner designed for natural gas connected to a propane/butane (campinggaz) mixture. Works like a charm.

Mr. Wizard - 31-1-2006 at 18:01

I'm sure this is well known to most, but for the benefit of the others, you have a smaller hole, or orifice, in propane fueled appliances. The natural gas appliances (nominally methane) have a larger hole. The propane needs less fuel and more air than the methane. This can be seen by the number of moles of carbon and hydrogen in each mole of the individual gasses. Propane appliances can be modified by making the hole bigger or by drilling the restriction hole to the correct size. There are charts available on the net, usually by BTU rating of the burner. Running a propane burner on natural gas will not give enough fuel or velocity to the flame, and you will get the lazy blue flame LiveWire experienced. If it was my burner I would check for obstructions, make sure you know what kind of fuel you are burning, and adjust the orifice accordingly. Propane is heavier than air, methane is lighter. Propane comes from a metal tank through a regulator, natural gas comes from a buried pipe to a regulator.

[Edited on 1-2-2006 by Mr. Wizard]

LiveWire - 2-2-2006 at 04:37

Wow, thanks for the info everyone.

I will try to return the burner to the store, but if they don't accept, you're saying I could fix it by making the gas hole bigger?

joeflsts - 2-2-2006 at 05:20

Yes, you could make the hole larger. This isn't a tough job but make sure you don't make it large enough to throw a cat through. :D

Joe

Mr. Wizard - 2-2-2006 at 09:52

As to making the hole bigger, go in small increments, as it's tough to make it small again. The orifice also gives velocity to the gas which is needed to induce air into the burner. Not enough velocity or air means a white tip on the flame and soot on your equipment. I have found the wire from steel cables very helpful in cleaning and enlarging small holes. Find some braided steel cable if the 1/16 to 1/8 inch (1-3 mm), cut a short piece off, and unbraid it. Mounting it in a short wooden or plastic handle makes it easier to use.


BTW what sort of fuel do you use? I know you said it comes out of the wall, but it could still be propane or natural gas.