blown forge input.

Fred.Rowe · Mar 26, 2006

I am building a natural gas forge. It is 24 inches high, sets verticaly, has five nozzels and is blown. I am using this for heat treat only. The forge is used to heat a 4 inch round pipe suspended in the center of the forge. This is my ox. free oven. I will be running a temp. of around 1400fh. or there abouts. This forge is set up with a thermocouple and a digital control. My question is this; In order to maintain the most constant temp. does it make sence to set the blower on a delay relay and have it come on before the gas and then shut off a couple of seconds after the gas shuts of, so as to have no air running thru the forge, therefore maintaining the temperature longer. Or is it more logical to leave the blower runnning and not worry about the heat loss caused by the air passing thru the forge. The forge has an exhaust port [4"] at the base where all the burnt gas leaves the forge body. I am fortunate to have free gas so the cost is not really the issue. More a question of performance. Fred

Here are a couple of photos that will help to clarify my meager discriptions.
The air control came out of the local school. I picked it up when they got a new gas heating system.
The chamber I am heating is a 20 x 4 x 1/4 inch stainless tube with the thermal couple up through the bottom.
The forge body itself is 12x24x1/4 inch. lined with 2" kaowool, satinite coated with itc-100 on top. I just need a selanoid valve for the gas.
Thanks for your input guys, Fred
A good friend who is a licenced welder came by and welded the, air/gas mixing chamber. I did not want any leaks in this part.

indian george · Mar 27, 2006

With my controller I use it to turn the gas off and on. I can dial in the temp with the gate valve on the blower and needle valve on the gas. The gas on shut off for a second and will reignite.
I don't know how this would work with your setup

Fred.Rowe · Mar 27, 2006

indian george said:
With my controller I use it to turn the gas off and on. I can dial in the temp with the gate valve on the blower and needle valve on the gas. The gas on shut off for a second and will reignite.
I don't know how this would work with you setup

I have the same setup, with a gate valve on the air and a needle valve on the gas. My controller information says it will hold the temp within two degrees so I figure the gas will come on pretty regular to hold the temp at set. How often does the gas come on in your forge? Do you use a standing pilot or an electronic igniter?
Thanks for your input, Fred

indian george · Mar 27, 2006

Fred.Rowe said:
I have the same setup, with a gate valve on the air and a needle valve on the gas. My controller information says it will hold the temp within two degrees so I figure the gas will come on pretty regular to hold the temp at set. How often does the gas come on in your forge? Do you use a standing pilot or an electronic igniter?
Thanks for your input, Fred

Fred: Once I got it dialed in it and up to temp it self ignites. All you hear is a click, click from the gas control valve.

Dan Gray · Mar 27, 2006

Fred.Rowe said:
I am building a natural gas forge. It is 24 inches high, sets verticaly, has five nozzels and is blown. I am using this for heat treat only. The forge is used to heat a 4 inch round pipe suspended in the center of the forge. This is my ox. free oven. I will be running a temp. of around 1400fh. or there abouts. This forge is set up with a thermocouple and a digital control. My question is this; In order to maintain the most constant temp. does it make sence to set the blower on a delay relay and have it come on before the gas and then shut off a couple of seconds after the gas shuts of, so as to have no air running thru the forge, therefore maintaining the temperature longer. Or is it more logical to leave the blower runnning and not worry about the heat loss caused by the air passing thru the forge. The forge has an exhaust port [4"] at the base where all the burnt gas leaves the forge body. I am fortunate to have free gas so the cost is not really the issue. More a question of performance. Fred

dang free gas

:thumbup:
to be O2 free you'll have to recyle the burnt gass back in after it's gone through the pipe..it's bunt and will drive out any O2 in the forge also it causes a pos press in side keeping o2 out from out side.. this is how the big units I worked around was set up..I mite add once you remove your steel you'll need to keep it o2 free also I'd biuld it with a
dump hole directly into the quench, fire in the quench will be your concern..
but with no O2 there it can't burn..
just 2 cents..

I may be reading the way you have this set up made, the units I'm use to uses the pipe as a indution type heater
I'm thinking your using the pipe to house your blade now? if so you'll still contact O2 removing to quench it right?

Fred.Rowe · Mar 28, 2006

Dan Gray said:
dang free gas :thumbup:
to be O2 free you'll have to recyle the burnt gass back in after it's gone through the pipe..it's bunt and will drive out any O2 in the forge also it causes a pos press in side keeping o2 out from out side.. this is how the big units I worked around was set up..I mite add once you remove your steel you'll need to keep it o2 free also I'd biuld it with a
dump hole directly into the quench, fire in the quench will be your concern..
but with no O2 there it can't burn..
just 2 cents..

I may be reading the way you have this set up made, the units I'm use to uses the pipe as a indution type heater
I'm thinking your using the pipe to house your blade now? if so you'll still contact O2 removing to quench it right?

Thats a good point, Dan. I had not thought about the move from my heated pipe to the quench tank. I do coat my blades with borax so there should not be much contact with the atmosphere. The four inch pipe, where I heat the blades is sealed on the bottom and has an insulated door on the top. I have made a jig that suspends the blade verticaly inside the pipe.
My quench tank is a five gallon Air-Void stainless that sits next to the h.t. forge. I completd the welding yesterday. I should have it up and running by the first of next week. I will post some pics. Fred

jhiggins · Mar 28, 2006

I for one, would love to see pics of your setup, Fred. :thumbup:

Dan Gray · Mar 28, 2006

Fred.Rowe said:
Thats a good point, Dan. I had not thought about the move from my heated pipe to the quench tank. I do coat my blades with borax so there should not be much contact with the atmosphere. The four inch pipe, where I heat the blades is sealed on the bottom and has an insulated door on the top. I have made a jig that suspends the blade verticaly inside the pipe.
My quench tank is a five gallon Air-Void stainless that sits next to the h.t. forge. I completd the welding yesterday. I should have it up and running by the first of next week. I will post some pics. Fred

OK I see, it's not like the atmospheric generating oven I was thinking of
to bad though,,with Free Gas

Burchtree · Mar 28, 2006

sounds cool -- you using stainless for your inside pipe?

Fred.Rowe · Mar 29, 2006

A picture is worth a thousand words.

Dan Gray · Mar 29, 2006

very interesting

indian george · Mar 29, 2006

Fred.Rowe said:
A picture is worth a thousand words.

This is true:thumbup: :thumbup: But if it is of your face one word will do UGLY HEHEHEHEHE!!!!!

Fred.Rowe · Mar 30, 2006

Dan Gray said:
very interesting

Dan, Does very interesting, mean; it will never fly or that you think it has promise? I know from your post that you have some expertise in the field. Give me your thoughts on this one. Fred

Fred.Rowe · Mar 30, 2006

indian george said:
This is true:thumbup: :thumbup: But if it is of your face one word will do UGLY HEHEHEHEHE!!!!!

I went to church and prayed for you, my son. The responce was "don't bother", there ain't no hope for the man.

Fred

Dan Gray · Mar 30, 2006

Fred.Rowe said:
Dan, Does very interesting, mean; it will never fly or that you think it has promise? I know from your post that you have some expertise in the field. Give me your thoughts on this one. Fred

HI Fred
the way you are making this is much different than the atmosphere generating gas oven that I know of. so I can't really comment a lot.
I see what your doing and understand it..
thinking your looking for a more controlled temper on the blade itself
and trying to keep it o2 free as much as you can.. as you mentioned using borax, PBC also will keep this from being a big problem anyway.

so I'm thinking that you're are looking to keep a controlled even heat mainly, right? the biggest thing that would come to mind would be the control of heat
on your chamber, of course we know that but thinking you'll have residual heat in the tube walls heating the inside of the chamber
so if this is not heated slowly once you get close to your target temp it may over heat the inside from this residual heat..
other than that I think it will work fine, that free gas should help nicely

I wished I could find some monel pipe, I've been itching to build a true
atmosphere generating gas oven
it's easy and a simple concept. that uses O2 free induction heat with re-circulating exht for O2 free heat which in turn causes a pos pressure inside the forge/oven to keep O2 out while operating..

and thinking also of setting up a simple automotive O2 sensor to monitor O2 in the burnt gas this is the easier part of building it.

automotive O2 sensors are self power generating starting at over 600 degrees ( up to 1 volt DC) and with a low voltage meter you can tell what you have for O2 to fuel ratio..also making the unit more efficient.
I think I'm rambling on now sorry..be sure to let us know how it works..
:thumbup:

Fred.Rowe · Mar 31, 2006

Dan Gray said:
HI Fred
the way you are making this is much different than the atmosphere generating gas oven that I know of. so I can't really comment a lot.
I see what your doing and understand it..
thinking your looking for a more controlled temper on the blade itself
and trying to keep it o2 free as much as you can.. as you mentioned using borax, PBC also will keep this from being a big problem anyway.

so I'm thinking that you're are looking to keep a controlled even heat mainly, right? the biggest thing that would come to mind would be the control of heat
on your chamber, of course we know that but thinking you'll have residual heat in the tube walls heating the inside of the chamber
so if this is not heated slowly once you get close to your target temp it may over heat the inside from this residual heat..
other than that I think it will work fine, that free gas should help nicely

I wished I could find some monel pipe, I've been itching to build a true
atmosphere generating gas oven
it's easy and a simple concept. that uses O2 free induction heat with re-circulating exht for O2 free heat which in turn causes a pos pressure inside the forge/oven to keep O2 out while operating..

and thinking also of setting up a simple automotive O2 sensor to monitor O2 in the burnt gas this is the easier part of building it. automotive O2 sensors are self power generating starting at over 600 degrees ( up to 1 volt DC) and with a low voltage meter you can tell what you have for O2 to fuel ratio..also making the unit more efficient.
I think I'm rambling on now sorry..be sure to let us know how it works..
:thumbup:

I am not familiar with the AGGO concept but I understand how it works from your discription. The automotive o2 sensor is an interesting idea. I will keep that in mind.

I will be running this unit up in about a week. I will let you know what the results are. Fred

blown forge input.

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