[SEL] (no subject)

[Rob Skinner]

> generate. I thought about resizing the orifice that the gas 
> comes out but the hole is really small and the smallest bit I 
> have is .020. Are there a variety of orifices available? What 
> should I do?

Hi Barry, 
I can't specifically answer your question in regards to your engine, but perhaps
some experiments of a couple months ago can guide you where you need to go.  You
can infer the basics from my description, then modify it for your particular
needs.

I was trying to make a suitable lamp for an engine.  The results varied from a
wimpy little yellow propane flame to a seven foot tall fountain of flaming
kerosene showering over my head.  It was totally bogus.

Most of my headaches were the result of not mixing enough air with the fuel to
get a hot flame.  Here's the basics of the design I settled on.

The propane bottle was a little one-pounder.  The valve and hose came from a
little hand-held plumbers torch.  The pressure coming out of the little bottle
will be the same as your 100 lb. tank.  

The burner is a piece of cold rolled, about two inches long, turned down to the
diameter where a piece of 1/2" emt can be firmly pushed over it and stay in
place.  It's bored ALMOST all the way through with a hole that is the diameter
needed to tap a 1/8" pipe thread.  

The hole is then tapped to 1/8" to accept the propane hose.  From the other end,
I drilled an orifice.  The diameter was about 0.025" to 0.028"   I don't
remember exactly, but this is a bit bigger than your 0.020".  

You can't just shoot propane out an orifice and expect it to burn.  Believe me.
Remember the previous statement regarding the shower of flaming kerosene.  You
need a mixer.

The mixing section is a piece of half inch emt, about three inches long.  About
3/4" from the end, I cut two slots 1/4" wide and 1" long for the introduction of
air.  That's it for the mixer.

Slip the mixer over the burner.  It should be a tight fit so it doesn't move
around, and the slots should not be covered.  The flame tended to shoot far out
and extinguish itself, so I took a strip of steel screen, rolled it up, and
stuck it in the end of the emt.  I think the screen slows down the gases and
allows mixing.  When you're running a small flame, it will prevent the gasses
from going back into your burner.  

Voila!  Big Blue Flame!  

The burner works very well.  If I was to improve upon it, I'd maybe try a bigger
orifice, maybe make the mixer longer, and maybe play with the screen.  But it
works so well now that there is little motivation to modify it.  

Just remember:

1.  You GOTTA get air to mix with the fuel.
2.  You gotta slow it down enough so your flame doesn't self extinguish.
3.  Setting yourself on fire detracts from your "fun time."  

Have fun.  Remain uncombustable.
Rob