I did such a thing and it significantly improved efficiency of the furnace.

http://old-smithing....e-z-dopalaczem/

Mod note: this is not an afterburner as much as a preheater

So ? the pipe coils in the front of the forge are pre heating the gas ??? or what ? tan after burner is taking the unburnt fuel and re burning it in my book, that I am not seeing done- also I cant read the language :mellow: that would help lol

The preheating principle is also used in hot air balloon burners.

Energy management, the hotter the input gases the hotter the flame will burn.

Aw Ok thanks

Not an afterburner but a recuperative system---well known in industry and in blacksmithing the Sandia Forge plans using a recuperative system have been out for decades. You may want to look at them as I think their method is easier/better.

He is preheating compressed air and injecting it below the GAS mixing jet. Not really a recuprative burner where you use the exhaust gas to heat the incoming air for your burner because the air in this example is brought in at pressure below the venturie.

The preheating causes the injected air to expand and along with it's already compressed pressure not only helps heat the incoming fuel mixture but also increases it's velocity by drawing more air in thru the primary opening at the mouth of the burner tube where the fuel mixing jet is located.

Fit's the definition as I know it:

recuperative furnace, noun
a furnace having its incoming air heated by exhaust gases, the passage of air and gases through the furnace being always in the same direction.

Do you know a term better suited to this exact type?

Thanks doc ! This is exactly what I had to write.
The aim of this project was to obtain extremely high temperatures with one burner in afurnace and by the way to reduce gas consumption. I managed to do it with just the materials available, and such tools at his disposal.

Fit's the definition as I know it:

recuperative furnace, noun
a furnace having its incoming air heated by exhaust gases, the passage of air and gases through the furnace being always in the same direction.

Do you know a term better suited to this exact type?

Thomas, OK I'll grant you that it is a recuprative forge as per your definition,but it is more. There is more gain in efficiency because of the fact that having the air injected below the venturie after it has been preheated and at velocity also increases the velocity of air coming thru the venturie thus increasing the velocity at the fuel jet which increases total efficiency. This is something that is not gained by simply preheating the incoming air to the burner. The only gain from simple induction preheat is thermal, with heated injection you gain thermal and volumetric efficiency.

I'm not wanting to be argumentative here,just trying to point out that this design has more to offer than simple preheating like the Sandia design offers.

As Ironwolf said, what language is it in. I can't get Babelfish to translate it if I don't know what to translate from. Pictures look interesting, also pictures on the tutorial.
I thought that I would just look at your profile, find out where you are from and get the language that way. I don't think that the language is Jersieze.

Wayne, the language is Polish.

Thanks doc,,,,wouldn't you know, BabelFish doesn't have a translator for Polish to English. I'll have to try something else.

Google translates

http://translate.google.com/translate?hl=en&sl=pl&u=http://old-smithing.com/palenisko-gazowe-z-dopalaczem/&ei=H_u6T-2YFKG

Thanks Sweany, It makes a lot more sense now. And thanks Tom. It looks like you used compressed air, I wonder about using a blower and running the air intake (between the blower and the gas inlet) by the door and is the added heating due to the pre-heat or just the added air

i cant under stand why pre heating the air supplied to the burner would make it more efficient, i know it peas and carrot comparison here but in cars u want cold air to be takin in, because cold air is more dense than warm or hot air. therefore it will have more oxygen per volume than the hot air.

Hans, the difference is that in a combustion engine, excess heat has to be disposed of with a radiator or air cooling system, and the confined explosion is the desired product.

The exact reverse is true in a gas forge. You want the pressure inside to remain low, and retain as much of the heat as possible. 75% of air, hot or cold, is inert Nitrogen, which at 72F is just robbing BTU's from the 2000F forge. Now if the air comes in at say 500F, you have a sizable energy savings, not having to heat and expel that cold Nitrogen.