My... Oneday furnace burner..

[NeoTech]

This is an extension of my furnace thread, but more about the burner..

So material is a piece of stainless tubing, some mystery steel bar, a mig tip and a cheap bunsen burner handle from the local store (Jula, for the swedes).

The coupling between the bunsen burner and the burner body is a R15 (plumbers connection) a piece of steel was turned so it fitted in the nut with the correct matching cone to the burner.. The tube and the nut was then pressed into the burner body with my shoppress, 6 ton of pressure to fit those to things togeter..

The main diameter up to the tip is 8mm, then it goes down to a M6 and then out through the mig tip with 0.8mm.
The main burner body was turned snug fit for the stainless tube.. When running the propane makes the whole think "shrink together" and a whole f**k ton of force was needed to seperate them..

The choke is milled so the tip of the burner and the end of the choke hole is matched. For 14mm slots was made.. after tests, this is way to much.. The choke is a piece of tube i had lying around at 50% i get a 30cm blue flame with no yellows or reds. And full choke i still get a blue flame with some yellows. Full throttle, and it cant maintain the flame at all.

The big steel ring slug thing is to center the burner tube in the furnace inlet tube. A M8 was threaded to secure the ring and the burner just slides with snug fit into the furnace some adjustments are possible here but..

And some pictures... (once again these are hosted on my blog so sorry for size).

[MetalCaster]

Nice work, I like it.

[NeoTech]

Thank you. 

[doubleboost]

If you can not maintain a flame at full flow
Try a bigger hole in your jet (mig tip)
This will slow down the gas speed and stabilise things
It takes very little change to make things work
John

[vtsteam]

Looks good!

Also looks like somebody got a little heat going in his furnace -- or at least the lid 

[NeoTech]

Think im gonna get me a set of microdrills and go up 0.1mm in the mig tip until it stabilises then.. As of know 50% throttle produces a great flame though but its a bit tinkerish to get it stable. poking that choke back and forth.


hehe vtsteam, im sorry to say that heat is from my plasma cutter when i poked the venting hole in the lid after i had cast it ;D

[vtsteam]

The choke adjusts mixture. A flare provides flame stability. The furnace itself can also do that.

The flare slows the gas air mix until it's speed matches the flame speed. At that point it burns. The flare is a taper, so somewhere along its length, as the gas air mix expands to fill it it slows enough to burn. The position of this flame front will depend on how fast the gas air mix is being injected, which depends on the pressure and orifice size.

So you can vary the flame position by orifice size, or by pressure adjustment, or by adding a flare. If the position of the flame front is too far away from the end of the burner, it is blown out. The flare allows a nice smooth range of positions for different gas pressures. In other words, somewhere in the flare, the flame front should be stable for a good range of pressures -- throttle settings.

[NeoTech]

so what you say is the burner could stabilise when put into the furnce with some luck, and well it couldnt and then i need machine some more parts.. Hmm i think this will need further investigation.. *and me go buy more propane* ;D

[vtsteam]

Neo, yes, a lot of people find a flare is not needed once a burner is installed in a furnace.  The hot walls maintain the flame.

[NeoTech]

So experimenting.. The torch tends to "stabilize" when the burner tube starts to switch over to redish color in the tip.. The gas end of the tube is still cool to the touch..
A flare didnt do much for it at all actually but im now thinking a diffusor of some sort.. like a fine mesh or similar could help.. Or am i wrong?

[vtsteam]

Guess you'll have to experiment and tell us!   

Flare is supposedly best 12 degrees btw.

[doubleboost]

Hi
Lads
The flare on my early burner ran very hot
The flame was stable over the full range
http://s261.photobucket.com/user/john970s0/media/076_zps1f18419e.jpg.html