I'm thinking about the gas log I installed in the fireplace. This has
a shut off valve, some kind of a small orifice (I never checked the
diameter), and the gas is fed to about 2 feet of perforated tube
arranged in an S curve. The gas mixes with the air AFTER the gas
leaves the perforated tube. This results in a dirtier, but more
visible flame. (Just the oposite of a Bunsen burner).

In your evaluation, try using regular gas pipe coming up to just
above the surface of the water in your test tank. You WILL want to
have some sort of an orifice restricting the flow just after the shut
off valve, and some sort of a diffuser just above the surface of the
water. I'm not at all enthusiastic about having the gas bubble up
throught the water. You won't get a smooth flow, and the water will
get saturated with natural gas. Once you get the mechanics worked
out, you can explore replacing any metal parts above the water with
glass. Heavy wall glass tubing in a wide range of diameters is a
stock item at any laboratory supply house.

I visualise two possible designs. The first is a simple glass tube
1/2 - 1" in diameter coming up to just above the surface of the water.
You would remove any water from the tube, turn on the gas, and light
it. At night, from a distance of more than a couple of feet, the
glass tube would be hard to see.

A more complex design would require a 4" diameter glass or plastic
tube ending right at the surface of the water, and an inside that a
much smaller tube 2" below that providing the gas. A small pump would
be constantly emptying any water which flowed into the larger tube.
The effect would be that of a 4" hole in the water with the flame
coming out of it.

PlainBill

On Fri, 09 Jan 2004 21:00:54 -0500, Mike Patterson
wrote:

On Fri, 09 Jan 2004 16:43:08 -0900, Offbreed
wrote:

Mike Patterson wrote:

Really like my new pond, finally seem to have the surrounding drainage
problem and the Mysterious Water Loss After Heavy Rain problem fixed,
so now I'm thinking...

How about if I run black gas pipe out to the the back end of the pond,
put on a valve there, then something like icemaker tubing into the
pond so that gas bubbles up near the center, then light it.

How about a glass or plastic tube for in the water, comming up to the
surface? It should not be any more intrusive than the bubbles.

Good idea, thanks. Even if it terminates under the surface, it would
still reduce the gas/water "exposure time" to a couple of inches
instead of 3 feet as I had been planning.

Mike

Mike Patterson
Please remove the spamtrap to email me.