Increasing my oven temperature

[Jerry]

In my business part of what I do is Tool & Die repair welding where I need to heat the tool steel to a certain temp. I built a oven that is 4' x 4' x 3' high and my buddy helped out with adding electronic ignition and a digital readout thermocouple.

The oven will reach approximately 700 + degrees. I have four pipe or gas runs every 12" on center say by about 4' long. I used a plug with a # 30 drilled hole for a orifice, then the 4' pipe slides over and in this 4' piece I have an area cut into for air to be induced by pushing bar that is connected to slightly larger pipe which opens slot in 4' pipe. I added this for air into system and it created a slightly bluer flame which you can hear becomes hotter and workes well.

Now the question, I want this to get even hotter say 1100 or so for stress relieving of weldments. I heard that if I induce the oxygen or air into the system before the orifice it would increase the heat, presently I am introducing air after orifice.

Any thoughts guys

[BillC]

I don't know a lot about these things, but here are a few thoughts:

Heat in the oven is an energy flow system. Heat in from the flame and heat out through the walls. Your limit on heat input is the amount of fuel you can burn, assuming you are getting complete combustion now. BTUs per pound or something like that... If injecting air prior to the orifice gives you more complete combustion then it is a good idea. Does the outside of the oven get hot? If so then you need better insulation.

Beyond that, I look forward to seeing the other responses to learn something...

Another thought, you probably need a controller (thermostat) to maintain the temperature without overheating the parts. Good Luck!

[Hobart Expert Rock]

INSULATION IS A LARGE CONCERN..........THICKER INSULATION KEEPS COLD OUT AND WARMTH IN.............. AT THE SOUTH POLE WE HAD 12" INSULATED WALLS.............AND A SAUNA..... .... ANYWAY............. I HAD A OCCASSION TO STAND BY A SMELTING POT ONE TIME MAKEING ALUMINUM INGETS............. WITH FULL PROTECTION......... AND I'M ALMOST POSITIVE THEY HAD TWO GAS INLETS INTO THE SMELTER..............THESE WERE INGETS ABOUT 3 FOOT AROUND AND 1 FOOT DEEP..............AND A THERMOSTATE IS A MUST..........IN MY ESTIMATION..............YOUR CALL BE SAFE.........GOT ANY PICTURES OF THAT FURNACE............... ROCK
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[chub380]

Try ceramic blanket for your insulation. Holds the heat in great. Stagger joints between layers 4- 2inch layers should be more than enough. then apply s/s mesh followed by refractory cement to finish the inside and to prevent the insulation from getting destroyed. If it is done properly you should be able to rest a bare hand on the outside of the shell of the furnace.

[Jerry]

Hey guys hows it going, I'll have to take a picture and post later.

The oven is wrapped inside,walls and top with 1300 insulation.
One of these days I may try some R&D but right now I'm totally swamped at work.

So for now I'll take weldments to someone else for stress relieving. But in future would be nice to do this myself.

[Pin Head]

You need to have the proper sized burner to get the temperature you need. Natural gas burns at about 1800 F, so you should be able to do 1100 F with the right burner. It has to have the proper air/gas mix or you can get carbon monoxide from incomplete combustion. This is something you don't want to fool around with lightly. It also has to have the right BTU rating for the size of the oven and you have one BIG oven there. I don't know how big you would need, but if you looked up a comparable oven on the net you could probably find the specs.