kubiack Posted February 28, 2011 Share Posted February 28, 2011 Does anyone know PSI needed for a naturally aspirated burner running on natural gas? My shop is feed with a high pressure line that I believe is 2 psi. It has to be run through a regulator to lower the pressure for the heater. I could easily tap into it at full pressure for the forge. Will 2 psi be enough or will I still need to use a blower. Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 28, 2011 Share Posted February 28, 2011 2 psi is really low as a max for a NA burner. I doubt the fact that it's NG instead of propane makes that much difference. Quote Link to comment Share on other sites More sharing options...
SoCal Dave Posted February 28, 2011 Share Posted February 28, 2011 Some burners require about 5 psi, or inches of water column for natural gas. You can call/email the company who made the forge and they maybe able to tell you what you need to know. Good luck. Quote Link to comment Share on other sites More sharing options...
Jack Evers Posted March 1, 2011 Share Posted March 1, 2011 Some burners require about 5 psi, or inches of water column for natural gas. You can call/email the company who made the forge and they maybe able to tell you what you need to know. Good luck. There is something missing in this post. Anyhow 1 psi is approx 28 inches of water. Five psi would be 140 inches of water. Quote Link to comment Share on other sites More sharing options...
kubiack Posted March 1, 2011 Author Share Posted March 1, 2011 Thanks for the replies. I have a home made naturally aspirated forge that is running on propane I want to convert it to natural gas so I don’t have to keep refilling my propane bottles. I was hoping to get by without having to convert it to use a blower. It looks like a little experimentation is in order to determine what kind heat I can get on 2 PSI. Quote Link to comment Share on other sites More sharing options...
Toreus Posted March 2, 2011 Share Posted March 2, 2011 IIRC, natural gas has lower specific energy rating (J/kg or BTU/lb) than propane. That should mean it takes slightly less air per weight of fuel burned. Not sure exactly what that means for an aspirated burner since I haven't dealt with one, but... maybe scaling down the burners would help? Anyways, I'm pretty sure 2 PSI would work plenty good if you add a blower- I run my propane one at less that 1 PSI using an old squirrel cage blower, and the specific energy isn't *that* different. Maybe just a black pipe T fitting, and that would be that? Quote Link to comment Share on other sites More sharing options...
MattBower Posted March 2, 2011 Share Posted March 2, 2011 Yeah, pressure isn't really an issue with blown burners. High pressure, low pressure - doesn't matter as long as you're delivering enough fuel mass to provide the BTUs you need. Quote Link to comment Share on other sites More sharing options...
Bentiron1946 Posted March 2, 2011 Share Posted March 2, 2011 It's been a very long time since I did any natural gas design work but generally you need to have either more air or more fuel. The reason the propane forge works so good with naturally aspirated burners is that you have a high energy fuel under a relatively high pressure inducing an air flow, this usually doesn't happen with natural gas. Natural gas is delivered at a much lower pressure for safety reasons unless you are a manufacturing facility requiring high pressure for your process, i.e. pottery, heat treating, foundry and even then you are sometimes required to put a natural gas pressure booster on your side of the meter unless you are an extremely large company. Here is a link to the maker of one booster http://www.gas-tec.com/ Some forges, heat treating ovens and melting furnaces come from the factory with these devices as a part of the unit and all that is necessary is to hook it up to the shut off valve, plug it in, light it off and you're in operation. Quote Link to comment Share on other sites More sharing options...
Ric Furrer Posted March 2, 2011 Share Posted March 2, 2011 Yeah, pressure isn't really an issue with blown burners. High pressure, low pressure - doesn't matter as long as you're delivering enough fuel mass to provide the BTUs you need. What Matt means is that whatever the pressure you have you can change the amount of BTU by making the pipe bringing the gas a different size....at a given pressure a 1/2" pipe can bring the gas, but a 16" pipe can bring more...with no change in pressure. What does the gas company say is your total BTU potential? I am getting a nat gas line put into the shop in the Spring...700,000 BTU or so. I have 60PSI at the road and will have ten PSI put to the shop and step it down as needed so I can use the existing small lines. a 3/8" flex gas line most use on their forges may not be enough to run a big forge at 2PSI, but you double that line and you can run a larger forge. Ric Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 2, 2011 Share Posted March 2, 2011 The real advantage of aspirated burners is that they require no power hook up making them portable systems. If you will already be tied to a NG line then a blown burner is much simpler and easier to build and use. I took a casting class once where the foundry was run off a NG line with a simple T into the output of an ancient hair dryer (pre blow-driers!) used as a blower. melted brass in the several pound amounts. Quote Link to comment Share on other sites More sharing options...
R.Rock Posted March 3, 2011 Share Posted March 3, 2011 Just went through this last month, couldn't get any heat out of the forge, come to find out that the shop is fed with 1/2" line from the meter, even though it was at 2 psi, the flow wasn't there, switched over to 1 1/4" line and the gas guy says that it is now capable of supplying 1,000,000 btu's to the shop, where as before it was only like 100,000. If you call the NG comp they will ask how far from the meter and what size line do you have and they have a chart that will estimate the btu output, I needed 450,000 as it is stamped on the forge, I wasn't anywhere near that. Love this site, been a lurker for a while just figured I could maybe help with your answer. Quote Link to comment Share on other sites More sharing options...
R.Rock Posted March 3, 2011 Share Posted March 3, 2011 sorry double post...kinda new at this Quote Link to comment Share on other sites More sharing options...
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