Subject: Re: Svea off-center flame?
> I have a Svea 123R that has a couple of small problems. One
> is that the flame is off-center. It seems almost as if the
> jet from the orifice is leaning to one side. Has anyone
> else encountered and fixed this problem? Is the orifice
> bad or is something else out of alignment? The orifice
> looks clean.
> Donald R. Newcomb * University of Southern Mississippi
> email@example.com * "The God who gave us life gave us liberty
> firstname.lastname@example.org * at the same time." T. Jefferson (1774)
I have one of these little Svea 123s myself. Thanks to the twin
miracles of carbeurator cleaning solvent and ultrasonic cleaning
machines, I'm still using an old pre-self-cleaning model I bought
in 1974. But, I digress...
If the orifice is clean (you say it is) and was not manufactured
wrong (I assume the flame used to be centered), then the off-
center flame almost certainly comes from the bell and/or the
burner place being out of alignment.
The burner plate is the plate at the top of the burner assembly,
slightly concave from above, on which the jet of fuel vapor from
the orifice impinges, which has the flame on its bottom. The
bell (I call it that because of its shape) is the piece that
screws onto the evaporator tube at the bottom, and which holds
the burner plate at the top. The flame goes upward through the
gaps between the bell and the burner plate.
The operating principle of these stoves, to be able to burn what
is essentially gasoline in a small, soot-free flame, it to
evaporate it with heat to create fuel vapor under pressure, and
then to shoot a jet of this fuel vapor out against a nearly-flat
plate. The turbulence where the jet hits the plate is so intense
that great quantities of air are entrained in the material
escaping sideways along the plate away from the "impact site".
(This turbulence also generates the characteristic "roar" of
these stoves.) Enough air is entrained to burn the fuel
completely, so it burns cleanly, and burns up before going very
For this to produce a symmetrical flame, the jet of fuel vapor
must strike the burner plate on its center, and the plate must
not be tilted or dented. A uesful test is to loosen the bell on
its threads, and then fire up the stove. Rotate the bell (its
hot!) 180 degrees. If the flame is still mostly in the same
place, the orifice is off center; if the flame rotates with the
bell, the plate isn't on straight.
If you need to bend the bell and/or the plate to straighten them,
go gently, the brass may be "hardened" (rendered stiff & brittle)
by repeated cycles of being heated & slowly cooled. Though,
IMHO, if they snap, that's an excellent indication that they
needed replacing anyway.
Robert Wieland email@example.com
Reality is all that stuff that doesn't go away when you ignore it.