Supplying gas to a small steam boiler

Check out Live Steam magazine, I'm sure those folks do this all the time. The British magazine Model Engineer also has had propane firing in the past, some of the larger US libraries subscribed and have back issues. Big on live steam locomotives and tractors. One approach I've seen for moving models was to cut down the regular Bernzomatic- style tanks to half-size or less. Burners were more or less home-made affairs, you'd have to see the articles.

Stan

Check out Live Steam magazine, I'm sure those folks do this all the time. The British magazine Model Engineer also has had propane firing in the past, some of the larger US libraries subscribed and have back issues. Big on live steam locomotives and tractors. One approach I've seen for moving models was to cut down the regular Bernzomatic- style tanks to half-size or less. Burners were more or less home-made affairs, you'd have to see the articles.

Stan

for a regulator, just look around. Lots of scrap barbeques go to the dumps.

OK, so this is where I am confused. I need to somehow connect to the propane cylinder's top , like how a torch head screws on it. Then I need to pipe that connection to a gas regulator, say from a gas BBQ, then a simple rubber tube will go from the regulator output to the burner infeed tube.

It's the cylinder connection/regulator set-up I can't figure out how to do yet.

I have an old Bernzomatic torch head. I suppose I can cut off the torch's top at the brass tube after the screw cap/valve assembly part/ but before the torch metering jet. Now I'll have a cut-off piece of brass pipe that screws on to a cylinder, but it will put out full bottle pressure when I open the valve. Then I suppose I can fit a compression fitting, or even solder a brass pipe connection fitting, to transition that to a pipe thread size that will feed into a gas regulator's input. output side is easy I suppose, just a pipe reducer to a rubber tube that slips onto the burner infeed tube.

Every BBQ regulator the same? How many PSI we talking in a typical small torch propane cylinder?

Thanks for your input.

PaulS

Propane camping stoves, e.g., Coleman, use the 14 oz propane cylinders. The same as torches. These stoves have a regulator built in to the propane "head". And a nipple on the output to attach a hose to.

Propane is stored as a liquid. The vapor pressure at room temperature is around 100psi. With a built in regulator, the tank psi would be a non issue. The output pressure is a few inches of water. I.e., insignificant.

Bob

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Think table top BBQ Gerry :-)} London, Canada

The pressure from a Bernzomatic bottle is quite low, and I, personally, would keep the needle valve and simply unscrew the pipe from the burner or from the head and screw in an adaptor to the hose.

The only reason for a regulator would be to keep the flow closer to constant as you run low in the bottle. The needle valve should be all you need for most things.

Most regulators are going to require too much pressure differential requirement to work well at propane pressures. Have you ever wondered why the gas regulator on the entrance to your house is so large in diameter? That is so it can be sensitive enough to regulate the very low pressures in a natural gas line.

Just do that after the needle valve and let the flow be set by the needle valve -- into a burner which is always open.

A quick google search found this -- in the summary without even following the link.

====================================================================== VAPORIZATION RATE - 100 lb. Propane Cylinder (Approx) ... Vapor Pressure at 0°F. 28 PSI. Vapor Pressure at 70° F. 122 PSI. Vapor Pressure at 100° F. 190 PSI ... ======================================================================

So -- you can see that the pressure is very sensitive to the temperature, and at the boiling point of water it won't go over 190 PSI.

Enjoy, DoN.

IIRC the boiling point of water is 212F or 100C and the figures above are given in F so no where near the boiling point of water..

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You're right. I was confused by the way the degrees symbol was printing, seeing it as 100\260F in the editor, and interpreting it as something like 100C/260F (and assuming that there was a mistake in the conversion.

The degrees symbol show up properly in the web page, and in my newsreader, but not in the editor -- another of those extended ASCII characters which don't show the same on all systems.

Thanks, DoN.