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more air reg
Great .gif, Al! Now I guess I'll have to break down and see if I can do an
illustration or two. If I'd had _Neon News_ in hand several months ago or
now Al's illustration, building an air regulator would have been much less
of a struggle. But since I went through the struggle anyway, I'll see if I
can do a .gif and post it. My regulator is a variation of Telford's
"internal" theme using 1.25" PVC with a couple of slots and an internal
piston which rises under pressure to progressively uncover slots on the
side. The one thing I do that's different is to have that piston assembly
at the bottom of the pipe; the pipe is capped so the column of air between
the cap and piston does two things: (1) provides a cushion and eliminates
hammer, and (2) adds resistance to the piston's travel and therefore acts
as a weight. More details with the drawing--hopefully in the next day or
so if I can boost my Corel skills sufficiently. [ Anybody else find that
Corel Draw seems less intuitive or more difficult to learn than other
products? ]
Anyway, I went to the internal piston design because I couldn't control
hammering with an external pipe, and also couldn't come up with a good scheme
for attaching weights. The first point was the larger of the problems...may
have something to do with the fact that the raw output of my smog pump blower
tends to be a little pulsed rather than absolutely smooth. Downstream of the
regulator the air is smooth (no surge tank) and the regulator itself is
really pretty quiet. The blower assembly itself is right next to the bending
table; it's in a fiberglass-lined wooden box and probably makes about as much
total noise as a dishwasher. (Fiberglass bats are enclosed in polyethylene
sheeting, btw.)
One other point on noise: Back in the design stage, several people on the
list strongly recommended using a 2nd set of pipes so the blower intake was
using outside rather than shop air. I couldn't agree more, and using outside
air cuts down on noise a lot--plus doesn't feed shop air, chemical vapors, or
other undesirables into the fires.
-JD
--
JD Schueler
lightem_up@socketis.net