Mike Patterson wrote:

My plan was to have the gas flow fast enough so that there is a net
"Continuous flow" at the surface to sustain the flame.

Natural gas is normally supplied to a residential customer at 4 PSI.
About the pressure you exert when you blow up a balloon
while LPG is regulated to 14 Inches of water column max.
which is about the pressure you exert when you exhale while breathing
normally.

any pressure ABOVE these and the gas WILL NOT light reliably.

What ever you do Mike, Please, Please, Please, DO NOT try to get more
gas flow
by connecting directly to the tank. The pressure in the tank is about
110#’s. It is
EXXXTREMELY DANGEROUS, and at that pressure it will not ignite at first,
but when the mixture 10 to 20 feet away gets to the proper proportions,
and you attempt to light it. It will ignite. But the results will be a
fireball of disastrous proportions. It will blow like a quart of
gasoline that was tossed on the ground and lit 30 seconds later. A big
WOOSH, FIREBALL,
and a FLASHOVER across a very large area.


Ideally, nothing protrudes above water level, so no pilot.
snip


Also the volume of gas you would require, IF it were possible to do it
would be astronomical.
I am paying $1.90-$2.20 / gal. Commercial rate.
Compared to $2.75 -$3.50/ gal. Residential rate.
For LPG here in eastern Pa.


good points,, but I think I'll do some empirical testing. If nothing
else the testing should be entertaining.

I don’t consider Fireballs of this proportion ENTERTAINING!!!

That's OK, keep rambling. In the immortal words of Number 5, "more
input!"



“NO Disassemble Johnny 5”

Mike S.
Chagoi
http://ourkoipond.com