Dear Richard Casady:

"Richard Casady" wrote in message
.. .
On Sat, 29 Sep 2007 13:57:27 -0500, Brian Whatcott
wrote:

(That would however take a hand pump capable
of supplying a flow at 15 psi plus. Like a bicycle
pump, or better? )

Grease guns are, some of them, capable of at
least. hundreds of psi. I happen to own a 0-5000
psi gauge. Bought it to check tractor hydralic
systems. I forget just what a grease gun pumped
it up to, but it was a lot.

But it was a *very* low flow rate. Brian is talking about "a
few" gallons per minute, to use cooler salt water in a tube on
the "fresh water" side to help carry off waste heat. And it is
going upwards a few tens of feet (then back down), perhaps
starting at atmospheric pressure. It would be hard work,
especially it it had to be kept up for an hour!

There is a reverse osmosis watermaker
intended for liferaft use, with a hand pump, and
RO takes hundreds of psi. That is what you want,
if you actually need high pressure.

I figure you probably can buy a small hand-held "single-shot"
pocket RO unit for just such a purpose...

David A. Smith

On Sat, 29 Sep 2007 12:59:39 -0700, Keith Hughes
wrote:

Gee, I didn't know you were using 'smart' molecules that travel *only*
in the direction you want them too. And they don't bump into each other
in the process. Wow, that's really neat, how did you accomplish that?

I noticed that.

Isn't the speed of sound, whatever it is, what it is because it _is _
the molecular speed? They both vary with temperature but not pressure.

Casady

On Sat, 29 Sep 2007 20:40:57 GMT, (Richard
Casady) wrote:


There is a reverse osmosis watermaker intended for liferaft use, with
a hand pump, and RO takes hundreds of psi. That is what you want, if
you actually need high pressure.

Casady


I looked up an example
The Katadyn Survivor 35 hand pumped was formerly
called the PUR Survivor 35 RO.
At 30 strokes/minute for 1.2 gall/hr - it costs $1500.

Not cheap.
Volume production ought to bring that down a bit?

Brian W

Brian Whatcott wrote:
On Sat, 29 Sep 2007 12:59:39 -0700, Keith Hughes
wrote:


My, my: "it's just plain wrong": he said a column of 32 ft,
Uhmmm, no, he said a "32' column of water". Can you see the difference?

Hmmm..Priestley certainly could. His water barometer had a water
column round 32 or 33 ft high.
How 'bout that! :-)

Quite true, which probably engenders the confusion. However, the
barometer *starts* with an evacuated column. That's how the atmospheric
pressure can push the water 32' up the column - you have 14.7 PSIA to
work with to lift the water. Same for a mercury barometer, or a McCleod
gauge, etc.

Different story than using the water column to *generate* the vacuum.


Gee, I didn't know you were using 'smart' molecules that travel *only*
in the direction you want them too.
....
Keith Hughes



Ho, hum: if half of them go in the wrong direction
until their first collision, it must take them a really, really,
REALLY long time to diffuse through the water vapor/rarified air mix!


Half? More likely 99.99999++% of them will not be traveling parallel to
the axis of the column. Half of those that *are*, are going in the wrong
direction.

How difficult this type of mass transport actually is can be seen by
looking at flow rates for water vapor from lyophilizer chambers to the
condensers (yes, I have done this a lot). Putting a 90° bend in the tube
connecting the chamber (where the ice sits on heated shelves) and the
condenser roughly (very roughly, given the variability of other design
factors) cuts the flow rate in half. That's in a 48" ID tube too! And
pulling vacuum through the condenser to maintain 50-100 microbar
pressure - i.e. maintaining a significant delta-P from chamber to
condenser. And with condenser coils maintained at -65°C.

It may seem counterintuitive, but the molecular motion you referenced
just *causes* the pressure, while providing little impetus for mass
transfer from point A to point B. And once the pressure reaches
equilibrium throughout the system, you have to rely virtually entirely
on diffusion, which is much, much slower.

Keith Hughes

On Sat, 29 Sep 2007 17:43:02 -0500, Brian Whatcott
wrote:

On Sat, 29 Sep 2007 20:40:57 GMT, (Richard
Casady) wrote:


There is a reverse osmosis watermaker intended for liferaft use, with
a hand pump, and RO takes hundreds of psi. That is what you want, if
you actually need high pressure.

Casady


I looked up an example
The Katadyn Survivor 35 hand pumped was formerly
called the PUR Survivor 35 RO.
At 30 strokes/minute for 1.2 gall/hr - it costs $1500.

Calorie expenditure by the survivor(s) could be a problem here.
The strokes for this RO unit can probably be performed by devising a
simple hydraulic pump to move gears, cams, and levers.
The pump cylinder itself would probably need an inverted U tube with
legs perhaps 32' or 33' long.
An initial vacuum might be applied to the top of the U-tube by using a
fitting that can be connected to the PUR Survivor 35 RO.
Once the water starts flowing through the vane at one end of the U
tube, and the vane shaft is turning the gears, cams and levers will be
clacking way, running that PUR unit on auto, good as gold.
After that it's all gravy until you have to change the membrane.
In the meantime you can spend your time fishing until rescued.

--Vic

Vic Smith wrote:
On Sat, 29 Sep 2007 17:43:02 -0500, Brian Whatcott
wrote:

On Sat, 29 Sep 2007 20:40:57 GMT, (Richard
Casady) wrote:


There is a reverse osmosis watermaker intended for liferaft use, with
a hand pump, and RO takes hundreds of psi. That is what you want, if
you actually need high pressure.

Casady

I looked up an example
The Katadyn Survivor 35 hand pumped was formerly
called the PUR Survivor 35 RO.
At 30 strokes/minute for 1.2 gall/hr - it costs $1500.

Calorie expenditure by the survivor(s) could be a problem here.

Oh yeah, right. Now you want to survive also. Geez, what next? :-)

The strokes for this RO unit can probably be performed by devising a
simple hydraulic pump to move gears, cams, and levers.
The pump cylinder itself would probably need an inverted U tube with
legs perhaps 32' or 33' long.
An initial vacuum might be applied to the top of the U-tube by using a
fitting that can be connected to the PUR Survivor 35 RO.
Once the water starts flowing through the vane at one end of the U
tube, and the vane shaft is turning the gears, cams and levers will be
clacking way, running that PUR unit on auto, good as gold.
After that it's all gravy until you have to change the membrane.
In the meantime you can spend your time fishing until rescued.

Sounds like perpetual motion to me, but I'm having a hard time
envisioning what you're describing above.

Keith Hughes

On Sat, 29 Sep 2007 19:44:35 -0700, Keith Hughes
wrote:

Sounds like perpetual motion to me, but I'm having a hard time
envisioning what you're describing above.

Of course you are, since it is basically nonsense. No mention of where
the energy comes from.

Casady

On Sat, 29 Sep 2007 20:38:17 -0500, Vic Smith
wrote:

The strokes for this RO unit can probably be performed by devising a
simple hydraulic pump to move gears, cams, and levers.

It comes with a simple hydraulic pump. I fail to see where adding
complicated machinery, with no power source whatever, will be of any
benefit.

Casady

Dear Richard Casady:

"Richard Casady" wrote in message
...
On Sat, 29 Sep 2007 19:44:35 -0700, Keith Hughes
wrote:

Sounds like perpetual motion to me, but I'm
having a hard time envisioning what you're
describing above.

Of course you are, since it is basically nonsense.
No mention of where the energy comes from.

Links were provided. "waste heat" (from what process?) and / or
"solar heat" have been cited so far. All the vacuum does is move
boiling temperature closer to ambient. Making more common
materials suitable for this application.

David A. Smith

N:dlzc D:aol T:com (dlzc) wrote:
Dear Richard Casady:

"Richard Casady" wrote in message
...
On Sat, 29 Sep 2007 19:44:35 -0700, Keith Hughes
wrote:

Sounds like perpetual motion to me, but I'm
having a hard time envisioning what you're
describing above.
Of course you are, since it is basically nonsense.
No mention of where the energy comes from.

Links were provided. "waste heat" (from what process?) and / or
"solar heat" have been cited so far. All the vacuum does is move
boiling temperature closer to ambient. Making more common
materials suitable for this application.

David A. Smith

Sorry David, I think you lost track of the posting train here. Richard
was responding to *my* response to the following post from "Vic":

"Calorie expenditure by the survivor(s) could be a problem here.
The strokes for this RO unit can probably be performed by devising a
simple hydraulic pump to move gears, cams, and levers.
The pump cylinder itself would probably need an inverted U tube with
legs perhaps 32' or 33' long.
An initial vacuum might be applied to the top of the U-tube by using a
fitting that can be connected to the PUR Survivor 35 RO.
Once the water starts flowing through the vane at one end of the U
tube, and the vane shaft is turning the gears, cams and levers will be
clacking way, running that PUR unit on auto, good as gold.
After that it's all gravy until you have to change the membrane.
In the meantime you can spend your time fishing until rescued."

Which appears to be a reference to a perpetual motion machine with no
energy source. Nothing whatsoever to do with the vacuum distillation
discussion.

Keith Hughes