The Flying Saucer Evapotron

[Ember]

The "Pages" section contains Chip Zempel's description of his
evapotron, a very different design with similar performance to the
Gray-B-Gon (typically 10-15 gallons/day). Here is Chip's reply, which
I copied from email, to a questioner:

I'm on the road right now, so I can't give you exact dimensions on my
flying saucer evapotron. (Besides, it's disassembled in storage.) But
I do know the height of the mesh cylinder is 36" which is the height
of the roll of 1/4" mesh hardware cloth I bought, and the roll was 10
feet long. So keeping in mind that (π * diameter = circumference), the
diameter of your cylinder (and therefore, of your flying saucer) can't
greater than 38" unless you want to buy a longer piece of hardware
cloth. So I would guess my saucer is approximately 36" in diameter.
(There's an overlap of a few inches when we wrap the hardware cloth
around it.)

As I explained in the article on the group's site, there is a plywood
ring that is screwed to the flying saucer which provides a surface for
stapling the mesh. The diameter of this ring is about 1/2" larger than
the saucer. The water drips off the lip of the saucer onto the plywood
and then runs down the mesh.

I have seen Ember's contraption and been very impressed by it. But I
have no idea about how his compares to mine for efficiency. (I'm going
to copy him on this email and see if he wants to chime in.) Here are a
few thoughts I have:

His relies on wind to operate. If there's no wind, there may be a
little bit of capillary action drawing water up the sides, but not
much. OTOH, there's almost always wind at BM, and if there isn't, I'll
bet people in the camp can be trained to give it a spin whenever they
walk by.

My design, OTOH, needs electricity to operate. So solar panels, a
storage battery, a reliable pump. (I've heard stories of people trying
to use aquarium pumps, etc., and having them fail in the dust and
harsh conditions at BM. It must be a pump designed to handle gunk!)
You say you have solar power, but do some math and make sure you've
got enough capacity to actually run the pump for 24 hours a day. (Our
first year, with a less efficient design, our pump ran 24 hours a day
and my 15W solar panel wasn't able to keep up.) Remember that all
those specs -- battery capacity, panel wattage, pump draw -- are for
"ideal conditions." Your solar panel will be covered in dust, your
battery will be overheated, and your pump will be pumping sludge!

Both designs look like they provide several opportunities for Murphy's
law to get in there and screw things up. I have a spare bilge pump,
and our camp has a lot of reserve battery power, large solar panels,
and a backup generator. I would assume that Ember is prepared to deal
with broken belts, ripped fabric, clogged bearings, etc. With anything
you bring to BM, it's worth it to ask yourself where the weak points
are and try to prepare.

I think in every way, Ember's design looks easier to transport. It
looks to me like it may be more fragile than my design, but it's got
to be a lot smaller, too. In my design, the kiddie pool is a major
pain to transport. It's about five feet in diameter and about a foot
deep, and it takes up a LOT of space! In fact, the first two years we
used it, our camp didn't have a truck, so at the end of the week, we
cut it into pieces and stuffed them into a garbage bag to make it
easier to pack out. And then we had to buy a new pool the next year.

In closing, let me suggest that you ask any further questions on the
group, in the discussion area, so that everyone gets to share the
information.

Chip