[TheForge] propane forge forced air

[Jerry Frost]

Started to reply to this a few days ago but it started snowing and I got
called in of some OT. Had to do it. <grin>

Eliminate the original burner and replace it with solid pipe.

What you're doing is supercharging a naturally aspirated system. The inducer
is drawing air at a metered rate by creating a vacuum using the primary gas
pressure of the propane through the jet. The system as designed will provide
more than enough air for proper combustion.

By supercharging it with an added blower you're forcing too much air into
the system.

Just remove the original burner and replace it with black iron pipe and a
propane supply line. You don't really need a jet for a gun (forced air)
system if you can control the pressure well enough, still It's simpler to
use a jet as most regulators don't turn down low enough.

For example: If your pipe running from the blower is 1" put a 1" x 1" x 1/4"
"T" in it before it gets to the manifold "T". Use a 1/4" F pipe die and over
thread one end of a 1/4" pipe nipple and thread it through the 1/4" leg of
the "T" then thread a cap on the end inside the "T". The cap being drilled
for the jet. You'll need to do a little experimenting to get a good jet size
but with a blower and decent regulator you'll have plenty of room for
adjustment. There are lots of ways to make a gun burner and what I outlined
is just one.

These are a couple rules of thumb to keep in mind though: 1) Propane and air
don't mix well without help so a long run from the jet to the forge, a
couple bends, "T"s, a swirl strip, etc. will help combustion. 2) You'll have
a length of pipe, manifold, etc. filled with a flamable air:fuel mixture and
for reasons I don't know a flame front doesn't travel around corners well so
at least one 90* "L" is a good idea. A blowout panel aimed in a safe
direction won't hurt either. 3) Unlike a naturally aspirated burner, a gun
operates under positive pressure so ANY leaks will put propane in the air.

That's about all I have off the top of my head.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks


----- Original Message -----
From: "thermoss" <thermoss@prodigy.net>
To: <theforge@mailman.qth.net>
Sent: Thursday, December 20, 2001 10:49 AM
Subject: Re: [TheForge] propane forge forced air


> I have a nc tool 2 burner knifemakers forge. recently I decided to build a
> manifold and add a forced air blower.
> The manifold blows air through the venturi openings. I put a air gate on
the
> "in " side of the blower to control the air flow .
> I am not seeing a great difference in the efficiency of the forge and the
> scale seems worse than without the forced air.  do I need to adjust the
size
> of the jets? larger  or smaller?also the back of the forge is not getting
as
> hot as the front.     any suggestions?
>