S, Simon Quellen Field pi?e:
I agree with?Christopher Erickson.
However, I also frequently encounter people who really want
to do something
a particular way, even if there are better ways to do it.
Hello...
Wery close. I want
to do/MAKE that and not to buy. I love to
DIY stuf.? Christopher Erickson point to the RV rafrigerator with
wery good link how that stuf work. The problem is that here is near
none used refrigerator available and new cost over $500. And that is
just to much. For day or two I can live just with insulated box and
ice pack from home, but wher I run out of ice I have no way to get
it (buy or whatewer). So I need some way to recharge it.
We might try to talk someone out of riding a bicycle across
the country, pointing
out that it is cheaper to fly, much faster, and that while
exercise is good for the
health in moderation, when done to excess it is harmful,
especially on public
roads behind and among motorists. But maybe the whole point
was to do it
on a bicycle.
What if just want to do that without fossil fuel. (not need to be
bycicle)
I was one of the first to try to get him to his goal in more
efficient ways.
But since this is a list for people interested in vacuum, and
he really wants to cool
his beer in a homemade vacuum assisted zeolite refrigerator,
let's just pretend that
he won't win some contest unless the task is done using a
vacuum and zeolites,
and see what we can do to help. Whatever tricks we devise to
produce a cheap
vacuum just might be useful to someone else.
So far we have suggested:
1. Steam condensed by ice until the required vapor pressure
is reached.
If we are talking water steam then should be chiled down with no
chiler?!?
2. Liquid dense metals flowing down a meter or two of pipe.
That is the option. But what metal? I only know the mercury and that
is toxic and near inposible to get.
3. Evacuating several bottles and connecting them one at a
time to the chamber.
Someone else calculated that is to bulky.
4. Using a port from a running internal combustion engine.
not enought vacuum
5. Buying a $130 roughing pump and a $30 inverter for a car.
I like to buy vacuum pump for $130. Cheapest I can get here is $350.
I think we've talked him out of trying to pump that much
volume by hand with a small
hand pump.
Is 5 litre to much for hand pump? I don't know. Just point me to the
right direction.
Some things we haven't (yet) discussed:
A. Building a big syringe and using a car jack to pull a
vacuum with it.
If I understand it right, that means pump with only 1 stroke. Then
the syringe should have 1000 litre volume. If I expand 5 litre of
1013mbar? for 200 times I got 1000 litre and 5 mbar. Just little
bulky.
B. Filling a tank with oxygen and steel wool and igniting the
wool electrically.
Don't know. Seem to be very hot.
C. Filling the tank with ammonia gas and opening a valve to a
water bottle.
Amonia is poison to avoid it.
D. Finding some low vapor pressure compound that is a liquid
at room temp
? ? ?but a gas at some reasonable temperature (i.e. the steam
idea, but with
? ? ?something that doesn't need to be chilled).
Just can't find it right one.
E. Buying some used car batteries and connecting the pump and
inverter to those
? ? ?so the car can be farther away from the cabin, and only
used occasionally to
? ? ?recharge the batteries.
Car bateries used as deep cycle will last wery short time.
F: Building a 33 foot high tower out of something cheap and
use water and gravity
? ? ?to draw the vacuum (has the same vapor pressure problem
-- needs cooling).
Actualy don't need tower as the lodge is on the steep hill. But the
wapour presure of water is to high. So it's need to be chiled and
now we have chicken and egg problem. I need that to chill not to use
cold just to do it.
G: Maybe that dense mud they use for drilling wells (barium
sulfate or hematite)
? ? ?could be used so instead of a tower, you can just put it
on the roof of the cabin.
? ? ?With mercury you could just use 800 millimeters, but a
slurry of barium sulfate
? ? ?is 2.5 times heavier than water, so the roof only has to
be 13 feet high. Using
? ? ?ethylene glycol instead of water would get the vapor
pressure down to a quarter
? ? ?of what water has. ?So fill a tank with ethylene glycol
and barium sulfate mud on
? ? ?the roof, and run a pipe down to a tank on the ground,
and open a valve. Both
? ? ?barium sulfate and ethylene glycol are cheap. Glycerin
will get you even lower vapor
? ? ?pressure, and olive oil even lower still. Safflower oil
may be the best. It won't
? ? ?take a lot of oil -- the mud will mostly be barium
sulfate or hematite. Hematite
? ? ?(rust powder) is the heavier of the two.
Hmm that seems possible to do. Just don't know where to get that
stuff. So just need to get something dense and with low vapour
presure. Oils seem little to light. aprox 850kg/m3 but have wapour
pressure far below 1 mbar. So just something heavier, nontoxic, and
cheaply available.
There are a lot of really bright people on this list -- we
should be able to come up with
a bunch of fun cheap ways to pull a vacuum.
I think so. That is reason why I post the question. And waiting
response how to do not how to buy.
That's the best post in this thread in my opinion. Thanks.
Slavko.
