AN IN-LINE WATERDROP
THE SCREENSYou should shape the metal screens in the collectors to make them either bowl-shaped or funnel-shaped. This will force the water to fall from the center of the screen rather than running down the edge of the charge collector pan. If water drips from the edge of the charge collector rather than from the screen, it will remove charge from the collector. And if the water from the screen forms a long solid stream whose tip extends vertically past the bottom edge of the pan, it will discharge the collector pan and the device will stop working. Only droplets, not streams, should leave the collector ring's central hole.
If you use a simple, pointed, cone-shaped screen, and if all the water
falls from the tip in a solid stream, the collector ring discharges itself
and the device stops working. I've found that a good shape for the screen
is a shallow cone with the tip punched inside-out like this (cross
_ \ / \ / \ / \ / \_/ \_/The water falls as droplets from the bottom edge. Make the screen cones fairly shallow, so no parts of them extend vertically outside the central hole of the ring pan. The pan acts as an electrostatic shield, and when water touches the inner, shielded part of the pan, *all* of its excess charge will travel to the metal. If the screen is within the sheilded volume, it will extract all the excess charge from each water drop. The screen must remain down inside the donut-hole of the pan.
_____ _____ / \ / \ | | _ | | Bundt pan with | |\ / \ /| | cone of screen | | \ / \ / | | within its hole. | | \_/ \_/ | | | | | | |- - - - -| |- - - - -|I used black electrical tape on the edges of the screen to hold it in place in the pans. You could tack it with silicone caulk for a more permanent design. Don't forget, the metal screens must make electrical connection to the metal pans. Keep each screen and pan touching together in at least one spot; don't accidentally break their connection with insulating silicone caulk.
CONSTRUCTION:The entire assembly of bundt pans and funnels can be suspended by fishlines from a hook on the ceiling, or instead you could build some sort of plastic structure to hold the parts.
The upper rain collector can be plastic or metal, or possibly use the
downspout from a convenient roof, or a hose, etc. The water supply
should be small enough that the funnels don't fill to overflowing.
Whether you use a funnel or a bowl with small holes, you must somehow
limit the amount of water flow so that it either comes from the bowl or
funnel as single drops, or as a short stream that breaks into drops inside
the inducer ring. If the stream is too long and the drops break loose
below the inducer ring, the inducer ring won't charge the drops and the
device won't work
You can increase the electric output current by fitting some sort of metal
"shower head" assemblies onto the ends of the metal funnels. These are
sold in garden stores as adapters for watering-can spouts.
If metal funnels are too expensive, you can also try using Tupperware
bowls with numerous small holes drilled in their centers. I put six holes
in mine, spaced in a circle about 2cm apart to prevent the water streams
from sticking together. To connect the plastic bowls to ground, stick a
piece of aluminum foil in the water in the bowl and clip your alligator
clipleads to the foil. "Ground" can be a water faucet, the screw on an
electric outlet, a big sheet of aluminum foil laid on the floor, or even
your body if the humidity is high.
The rings and funnels should be one or two inches apart. It's OK to let
the end of each funnel extend within the hole of each inducer ring below,
as long as the droplets break free of the stream before the stream exits
bottom edge of the inducer ring.
To suspend the rings and bowls, I glued three small Plexiglas "ears" on
all the rings and funnels. Then I ran three lengths of #20 plastic
insulation "spagetti" tubing up the sides, tying it to each "ear," then
tying the whole thing to a hook in the ceiling. I could have used fishing
line instead. Don't use wire to support the rings, not even if it's
insulated wire. The support must be a very good insulator. To speed
things up you might try simply tying knots in the right places in the
fishline, then glue the knots to the pans with gobs of silicone caulk.
(Use tape to hold the lines in place while the caulk sets.) Hang the
whole thing from a ceiling hook.
______ \ / Grounded _____\ / Funnel | || w/shower head V || /\ __________ __ / \ / \ _________________o | |___|____|___| | Output leads | __________o | __________ | | / \....../ \ ______| | |___|____|___| | | | | | | ______ | | \ / Grounded | | ____\ / Funnel | Connect the bundt pans | | || | together using bare wires | V || | and tape, or using alligator | /\ | clipleads found at Radio | | Shack stores | __________ | | / \ / \ ______| | |___|____|___| | | __________ |__ / \....../ \ |___|____|___|This device seems to work even in extremely high humidity. Apparently the electrical leakage along the surfaces of the thin plastic fishline is small enough that the device can still work even with that leakage present. Thinner fishing line might work even better, since the thinner the support lines, the less their surface area. The less their surface area, the less the electrical leakage during high humidity.
Any liquid can be used as long as it is slightly conductive. In theory
oil will not work because it's an insulator. Too bad liquid mercury is
poisonous, mercury would work fine. Tapwater works OK, since impurities
make it conductive enough. I doubt that salt water would work better, but
it would be something to experiment with. Ultra-pure de-ionized water
might not work because it's almost an insulator. For a science fair
project you could even try fruit juice. When people ask you why, just say
"because acids create mobile ions, leading to higher conductivity, and
also because I wanted to make a big, sticky, disgusting mess!" :)
Did you build the "classic" Kelvin generator first? If not, then I can't
help you. This "in-line" version is an advanced project. It's much more
flakey and difficult to make operate. Beginners should go back and try
the "four coffee cans" version first.
For further info, debugging, references, and "how it works," see my other
Lord Kelvin's Waterdrop Generator