Question about propane burners

[RaymondMillbrae]

Hey folks,

I have a question for yall.

I see a whole bunch of different propane burner casting set-up's...but no backchecks.

I built my wife a lampworking table that uses a propane torch, and I installed backchecks on each hose. I also weld using oxy-acetylene, and also use backchecks on the lines.

Why do I not see backchecks on the propane lines? Is there not a danger of a spark flowing back into the line and then igniting the tank? Or is the LACK of a secondary oxygen line the reason a backcheck is not needed?

In Christ: Raymond

[jbrown]

Propane is just not as volatile as acetylene, and there is no danger of detonating a propane tank like there is acetylene. I also don't know of too many people using pressurized oxygen with propane tanks. If you do and don't use backchecks there is a small risk of flowing oxygen back into a propane tank and making an explosive mix in the propane tank when it runs on empty.

You won't ignite it cracking a valve (like you can acetylene) though, so unless you are in a habit of holding a lit match to your empty propane tanks, you'll probably never know it. Propane is pretty hard to flashback, unlike acetylene too.

All the propane fillers are supposed to purge the tanks before filling too, so you wouldn't end up with a dangerous tank after the fact.



Hey folks,

I have a question for yall.

I see a whole bunch of different propane burner casting set-up's...but no backchecks.

I built my wife a lampworking table that uses a propane torch, and I installed backchecks on each hose. I also weld using oxy-acetylene, and also use backchecks on the lines.

Why do I not see backchecks on the propane lines? Is there not a danger of a spark flowing back into the line and then igniting the tank? Or is the LACK of a secondary oxygen line the reason a backcheck is not needed?

In Christ: Raymond

[jmsj]

Raymond,
I believe in oxy/acetylene welding the greatest risk is the flame traveling back up the oxygen line. The flame is always looking oxygen, fire cannot exist without oxygen. But in a super rich oxygen enviroment a spark can cause a flash over or explosion. When you turn the oxygen off the flame could travel back up the oxygen line because the oxygen line has more O2 than atmospheric air.
I went to a natural gas safety class yesterday and the representitive told us that natural gas will only ignite in a 15%-5% mixture with air. I asked him if it was the same with propane and he said he wasn't sure about the % of the mixture but there would still be a mixture necessary. The point I am getting to is our smelters are probably fired by propane and mix with oxygen is at the burner versus oxy/acetylene which combine in a mixing chamber in the handle. So when you turn the propane off to your smelter the gas goes out the line looking for oxygen. IIRC
All this said I put one on my smelter. But I did it because it had a quick disconnector already built in and had been lying around in the tool chest fo many years unused. jmsj

[RaymondMillbrae]

I guess I spoke...err...wrote, too soon.

After some thought, I realized I was correct. The difference between using JUST propane, verses the other set-up's I mentioned above, was the second OXYGEN line.

Duh!

JMSJ,

oxygen in itself is not flammable, so there is no need to fear the flame going up that line. The problem is using oxygen with propane or acetylene. Those two fuels are flammable, and even volatile with oxygen added to the mix.

What we shoul all be fearing is the acetylene or propane tank going off! (CHECK THIS OUT (http://www.youtube.com/watch?v=KAyuq8sDCeg&feature=fvw))!

When you have some type of torch, the nozzle tip is where the fuel and oxygen meet (oxygen/acetylene, or oxygen/propane), which is where the problems may arise...and go back into the fuel line.

So anyhoo...without the oxygen pressure added to feed the fuel, there is not really a need for a backcheck valve.

But then again, I am still leary of how close some of yall have your propane tank to 600 - 900 degree molten lead. (Also notice how some of the propane lines immediately under the burners are not protected/covered in case of lead spilage). And I would definately do a double-check for a possible leak of your fuel line!! (Squirt some soapy water of your lines every once in a while to check for a leak).

Thanks again for your ears.

In Christ: Raymond

[44fanatic]

Not a welder nor have ever worked with anything other than a small propane torch...

I would think that if there were a concern of a propane tank blowing up, all of the BBQ grills, turkey/fish friers and small torches would have additional safety mechanism intstalled.

[RaymondMillbrae]

44Fanatic,

you would think so, huh?

But after some of us "tweek this"...or "cut that"...or "remove this"...I wonder what we really have under our smelting pots. :o

In Christ: Raymond

[44fanatic]

44Fanatic,

you would think so, huh?

But after some of us "tweek this"...or "cut that"...or "remove this"...I wonder what we really have under our smelting pots. :o

In Christ: Raymond

Your key words...tweek, cut, remove. If you are doing that, then all precautions should be taken.

[44fanatic]

In all seriousness, no sarcasm, I will defer to your expertise.