View of the base cabinet
picture pretty well says it all. Clockwise from the left: :
volt power supply -- This is a common, open-frame switching
supply put in a box. 6 amps should be plenty of power. xxxxxruns:
indicator -- Magnahelic gauge registers 0 - 6 inches of water.
Organ is set to run on 4 inches.
blower in a box. I had a stroke of good fortune -- I was able
to find a blower at a surplus equipment vendor capable of a
pressure of more than 6 inches of water. It is electronically
controlled and relatively quiet. I enclosed it in a wooden
box, lined with carpet as sound insulation. As the photo shows,
it draws air in through an automotive air filter.
-- three black hoses are partly visible in this photo. The hose
material came from Home Depot, and were originally intended
for garden fountains. They are smooth on the inside. One hose
connects the blower to the pressure regulator; the remaining
two connect the regulator to the wind chests. The white plastic
pipe is Home Depot, too. It's bathroom sink drain hardware.
regulator. This is simply an air box with a round hole in the
top. A weighted hinged lid covers the hole. As the pressure
increases sufficiently to lift the lid, it opens and the air
escapes, thus regulating the pressure. The gray-colored brick
provides sufficient weight to regulate the pressure at 4 inches
of water. By loosening the clamp and sliding the brick left
or right, the set-point pressure is adjustable. This design
seems to work, but THE JURY IS STILL OUT on whether it
is truly viable! Check back with me later and we'll see if I
have to modify it as I get deeper into testing. .
Making the Pressure
aged circle-cutter was used to cut the hole for the regulator, and
to mount the Magnahelic gauge.
pre-drill the 1/4 inch pilot hole and clamp the plywood to the
table of the mill
cut the circle. I cut from both sides and met in the middle -- that
way, there was tearout.
tool makes me keep my hands in my pockets!!
Here I'm shaping
the "lid" with the tool-post router
I know I got
carried away here, using ball bearings where a cheaper bearing would
do as well, but I had the bearings in the junkbox. That and a bit
of 1/4 inch shaft and, presto!, I have the pivot for the valve.
Here you see
the regulator assembled and in situ in the organ. Notice the red
felt just visible under the valve "lid" (to insure a seal)
and the paper shim under the hinge block (to adjust it perfectly
level). The brick (painted with clear Varathane® to minimize
particulation) is the pressure adjustment. Move it to the right,
and it increases the pressure; to the left, decreases. The aluminum
clamp locks it in place. THIS DESIGN HAS YET TO BE TESTED -- although
it passed its initial functional test, but won't consider it a success
until it performs well under all playing conditions.
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