Ofeldt boiler

A special section just for steam engines and boilers, as without these you may as well fit a sail.
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DetroiTug
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Re: Ofeldt boiler

Post by DetroiTug » Tue Jan 21, 2014 4:42 pm

Hi Fred,

The iron work supports on the lower are very close to the burner. Apparently it doesn't get as hot as that is in the base of the flame. The completed boiler with burner attached is only about 19" tall. Note: one of them is like upside down house roof, that is where the 1/4" pipe runs through for the lower sight glass connection. The angle is positioned to shield the tube to prevent boiling and inaccurate sight glass readings.

The tubes inside are Tig welded to seal the joint and they are Mig welded outside for structural purposes only. It would be nearly impossible to weld all of them on the outside with Mig all the way around. I got very close, but I would have no confidence they would seal by themselves. The Tig is much better for sealing in my experience. It is slower and affords much more control.

-Ron
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DetroiTug
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Re: Ofeldt boiler

Post by DetroiTug » Sun Jan 26, 2014 2:50 pm

Getting the burner and vaporizer assembled.

The burner is a very clever adaptation of the original Ofeldt design by my good friend Tony Grzyb. It's simply made from electrical conduit. Hack saw slots instead of drilled holes. We're hoping to run this on kerosene. One of the unique features is the mixing tube or throat does not allow raw fuel to enter the burner chamber and blow back as many of these will. It just runs right back out.

Image

Tested it on propane it fires perfectly.

Image

Image

-Ron
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fredrosse
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Re: Ofeldt boiler

Post by fredrosse » Sun Jan 26, 2014 3:57 pm

Very nice burner setup, looks like it would be ideal for a VFT as well, with a smaller center section. Is the burner running on vaporized kerosene or propane, or natural gas?
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DetroiTug
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Re: Ofeldt boiler

Post by DetroiTug » Sun Jan 26, 2014 6:29 pm

Hi Fred,

That is on propane in the burning pic. We simply removed the tube and torch head from the propane torch and stuck it in the mixing tube to test (there is a regulator of unknown pressure and flow in the main valve of this one) . I was really impressed at how smoothly it ignited and the flame spread. The center section could have three or four rings of small holes drilled to burn in that area as well I would think. Maybe, maybe not. With an Ofeldt (we're thinking) there should be no flame on the center drum as it would disrupt the internal circulation, where the water enters the tube at the bottom and travels up the heated tubes for steam generation. The center drum acts as a reservoir and a downcomer.

These vaporizing burners are a build and test process. This one works really well. It took five or six tries beforehand though.

From what I understand, kerosene is more difficult to vaporize than gasoline/petrol, so the current one may not be suitable. We'll just have to try it and see.

The burner, casing and vaporizer only weighs 16 pounds. The original was cast iron and very heavy.

-Ron
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