Natural gas forge?

Take this all with a grain of salt, because I know any of it for certain, and dealing with flammable gases is obviously sort of dangerous :D

We used natural gas to run the forges in a fabricating/welding metallurgy class I took. They were vertical forges with a blower, and seemed to operate with the same basic principles a propane forge does.
After talking about it a little bit with the professor, the big problem with them seemed to be the pressure you are supplied on natural gas lines. They measure it by water column, and I can't remember what the max was, but it works out to less than 1psi.
Near as I can tell that pretty much eliminates you being able to use a normal venturi burner because you can't get enough pressure from the fuel going into the burner to draw air in behind it.
It also would mean you get a smaller volume of fuel out of a given orifice/jet than you do from a propane line running higher pressure. So you would either need to use multiple burners, or use a bigger orifice to get the same heat.

I guess thats why they had a 3" natural gas line feeding our forges and stuff at school :eek:
 
Erick: What size NPT pipe is going into the burner???? After we spoke the last time, I was thinking that if you have a 3/4 NPT pipe into a 3" chamber reduced down to 1 1/2" pipe to the burner. I'll have to draw it up so it will make it clear, because I am confusing myself. ( I know it doesn't take much)HEHEHEHEHE!!!!
 
A typical natural gas service going into a house has 6" pressure on a water column. There are 27.7612" pressure on a water column in 1 P.S.I. This makes the natural gas pressure less than !/4 P.S.I. Some commercial installations get their gas at a higher pressure. Usually 1 P.S.I. up to 10 P.S.I. They might go higher, but 10 P.S.I. is the most anyone gets in our system. In order to get the right amount of B.T.U.'s, you need a larger oriface. I do not know anything about how much pressure you need to run a venturi type burner.
 
Your natural gas company can supply enough pressure to run a power plant.
You probably would be on 2lbs, with a compensating index on the meter from them to read and bill your properly. You would need a regulator at your equipment to adjust your pressure to your needs. Service lines on residents (depending on area or city in US) usually are from 70 to 12O psi before being regulated down at the meter. Normal pressure on house piping is 1/4 lb. or 7" of water column on a manometer. Any pressure higher that this on the normal index will give you more gas than what you are paying for as the standaard meter index is reading for a setting of 7" water column adjustment. Hence, if you require and they give you higher pressure...say 2lb, they put a compensating index on your meter to measure the gas flow properly and bill you correctly.
Since the piping and regulator are past the meter, the cost of the pipe, regulator and installation would be at your expense. They will set you up for the pressure you need, but you will probably be classified as a business account to them. The gas will be cheaper per therm, but your customer service charge will larger each month.
You can run a much smaller line for a longer distance when it is on a higher pressure, it just needs to have a regulator to adjust it down to your working pressure at your equipment.
Call you Local Distribution Company and they can get you squared away.
Natural Gas companies run thousands of boilers, turbines etc. across the US, your application is peanuts to them.
Could not resist chimming in, I am a COO of a Natural Gas Company.
A great product from mother earth, that has nothing but an odorant added to it as it is odorless and tasteless. Safer than propane as it is lighter than air and propane is not, and will settle and pocket if it leaks. In most places, it is quite a bit cheaper at this time also.
They will be glad to help you out. Good luck!
 
Some years ago I decided to switch from propane to natural gas, mostly because I was tired of lugging a 60-pound bottle back and forth to the station, and it was always running out when least convenient.
I checked with the gas co. They were very helpful. They suggested I go with 1-inch line off the meter on a separate circuit and that would probably be enough. If not, they'd be happy to change the meter to accomodate. My 2-burner blown Mankel is a 100,000 BTU 'appliance'. They noted that a typical pool heater is about 500,000 and those almost always run off normal residential meters.
In short, I run my forge and three salt pots on natural gas.

Don't let anyone tell you you can't forge weld with natural gas. I do it all the time. (I once had a run in with an ABS Master Smith when someone at a clinic he was running pointed me out and told him I said I was welding with natural gas. He felt the need to publicly repudiate the concept. I shrugged and said "I just did it yesterday.")

I've found the salt-pot burner design on Don Fogg's site is suitable for natural gas. I'm confident it would be sufficient to run a very serviceable forge. Also, Darren Ellis is a forge maker of some repute. He sells parts.
 
At work I use natural gas forges. They run off 2lb lines using 1/4 inch pipe as the apatures. The burners will get a forge up to welding temp.


WS
 
Erik, I use two natural gas forges. One is a whisper lowboy, which is a 3 burner venturi system. Welding temp is acheived with 15 lbs pressure. Forging temps are 12 lbs or so. My heat treat oven operates at 15 lbs also. I am running well head gas, that carries a line pressure of 28 lbs in an 11/4" line. I use a regulator to adjust the pressure. This is raw gas, that has not been processed and contains all the gas products; propane, butane and the others. I don't know where you are getting your NG, so, don't know if this is relevent.

Fred
 
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