Energy Recovery (Clark Pump) Water Maker Pumps?
 

Does anyone know of a source for an energy recovery (i.e. Clark Pump) type
of pump that's available on the open market? I would like to replace the
pump on my watermaker with such a pump.

-- Geoff

Energy Recovery (Clark Pump) Water Maker Pumps?
 

Geoff Schultz wrote:
Does anyone know of a source for an energy recovery (i.e. Clark Pump) type
of pump that's available on the open market? I would like to replace the
pump on my watermaker with such a pump.

-- Geoff

Aahhh the holy grail... Seriously, I would like to do this as well.
A fellow on the liveaboard list suggested contacting all the Spectra
dealers in the US and getting a price for a replacement. I recall the
price for the Clark pump alone was ~$3K.

The class of device is generally known as a hydraulic intensifier, but
all the commercial ones that I know of are suited for air or hydraulic
oil, not seawater

Evan Gatehouse

Energy Recovery (Clark Pump) Water Maker Pumps?
 

Drop Glenn, of rutu fame, a note. I'm sure he has the answer....

Energy Recovery (Clark Pump) Water Maker Pumps?
 

Don't ask me! I stared at that clear plastic demo version for hours at the
boat shows trying to figure out how it works! When it finally dawned on me
it was incredibly simple but it takes some high class machining to make that
valve block. I can see why they cost so much. Even with a CNC milling
center it has to cost $300-400 just to mill out the valve block. I think
there are at least 3 WM makers offering Clark pump based systems now and
none of them will sell the pump without a full system.

At one time Spectra had an exploded parts sketch and a parts list with all
the o-ring dimensions that was enough to reverse engineer it but I think
they took it down after I pulled out my calipers at Annapolis a few years
ago to get a few last dimensions. :-)

The valving is similar to a Worthington shuttle pump used on steam
locomotives to feed boiler water but what makes it work is the piston rod.
The water on top of the piston is forced into the membrane. As it comes out
it goes to the back side of the piston to help push new water through but
the rod takes up about 6 or 7% of the cylinder volume so there is not enough
room for all the water to fit. It has to go somewhere so it is forced out
through the membrane.

What took more time to figured out is the system pressure. Ignoring
friction loss it should recover about 93% of the energy put in but the feed
pumps they use can only get to about 35-40PSI so I figure the system
pressure is around 600PSI. That is enough to produce some fresh water but
it is not enough to run the membrane at the nominal 12% recovery rate at
800PSI. Ran 600PSI through a SW30-2520 on my Filmtec simulator software and
come out with a 6% recovery which is about the displacement of the pump.
OTOH, gallons per amp hour is what counts so I guess driving the membranes
at a low rate is a non-issue. You just have to get used to the constant
clump-clump of the pump for hours on end.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Skip Gundlach" wrote in message
oups.com...
Drop Glenn, of rutu fame, a note. I'm sure he has the answer....

Energy Recovery (Clark Pump) Water Maker Pumps?
 

So, is the clark pump the basis for a supposed increase in efficiency?
I'm not real fond of even the 1.4A/gallon Spectra claims, but then I
looked at others and saw 3-4x that number...

Working on very low pressure pumping, myself, at the moment...

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/p7rb4 - NOTE:new URL! The vessel as Tehamana, as we
bought her

"Believe me, my young friend, there is *nothing*-absolutely
nothing-half so
much worth doing as simply messing, messing-about-in-boats; messing
about in
boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter,
that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never
get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to
do, and
you can do it if you like, but you'd much better not."

Energy Recovery (Clark Pump) Water Maker Pumps?
 

Yes. A simplified example. The formula for pump horsepower is
(GPM*PSI)/1460 so moving 3GPM at 800PSI requires 1.64HP. Moving the same
3GPM at 50 PSI requires .1HP. 1 HP= 746 watts (62amps @12V) so the high
pressure pump will draw 100 amps and make 20 to 22 gallons of product an
hour for about 5 amp hours/gallon. The low pressure system draws 6 or 7
amps and might produce 7 or 8 gallons an hour for about 1 amp hour.gallon.

In reality friction and pump losses will make the ratios more like 6 or
7AH/gal and 1.2 to 1.5AH/gal but the Clark pump based systems are still far
more efficient and running a 1.5 to 2HP pump for an hour is really not
practical on a battery bank. You just have to choose between the extra $3K
for the Clark pump or $4K for a genset to run the high pressure pump.

That is why I chose $150 and some sweat equity for a belt drive off the
engine. :-)

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Skip Gundlach" wrote in message
oups.com...
So, is the clark pump the basis for a supposed increase in efficiency?
I'm not real fond of even the 1.4A/gallon Spectra claims, but then I
looked at others and saw 3-4x that number...

Working on very low pressure pumping, myself, at the moment...

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
http://tinyurl.com/p7rb4 - NOTE:new URL! The vessel as Tehamana, as we
bought her

"Believe me, my young friend, there is *nothing*-absolutely
nothing-half so
much worth doing as simply messing, messing-about-in-boats; messing
about in
boats-or *with* boats.
In or out of 'em, it doesn't matter. Nothing seems really to matter,
that's
the charm of it.
Whether you get away, or whether you don't; whether you arrive at your
destination or whether you reach somewhere else, or whether you never
get
anywhere at all, you're always busy, and you never do anything in
particular; and when you've done it there's always something else to
do, and
you can do it if you like, but you'd much better not."

Energy Recovery (Clark Pump) Water Maker Pumps?
 

What took more time to figured out is the system pressure. Ignoring
friction loss it should recover about 93% of the energy put in but the feed
pumps they use can only get to about 35-40PSI so I figure the system
pressure is around 600PSI. That is enough to produce some fresh water but
it is not enough to run the membrane at the nominal 12% recovery rate at
800PSI. Ran 600PSI through a SW30-2520 on my Filmtec simulator software and
come out with a 6% recovery which is about the displacement of the pump.
OTOH, gallons per amp hour is what counts so I guess driving the membranes

The Shurflo pumps they use are set to about 100 PSI. THus they do get
the ~800 PSI needed for decent efficieny.


at a low rate is a non-issue. You just have to get used to the constant
clump-clump of the pump for hours on end.

Ever hear a PUR Powersurvivor? They are not as quiet as the Clark
pumps by about 10 dB!


Evan Gatehouse

Energy Recovery (Clark Pump) Water Maker Pumps?
 

Hi Glenn,

Do you happen to still have a copy if the info you mention below? I
know a penny-pinching mad scientist type that would be interested in
the challenge of building on of these.

On Wed, 17 May 2006 12:20:10 -0400, "Glenn Ashmore"
wrote:

At one time Spectra had an exploded parts sketch and a parts list with all
the o-ring dimensions that was enough to reverse engineer it but I think
they took it down after I pulled out my calipers at Annapolis a few years
ago to get a few last dimensions. :-)

--
BRENT - The Usenet typo king. :)

Energy Recovery (Clark Pump) Water Maker Pumps?
 

I printed it all out several years ago when I was designing my system but
can't find the paper anymore. They looked like part of the owner's manual
so you might try to find someone with a system.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Brent Geery" wrote in message
...
Hi Glenn,

Do you happen to still have a copy if the info you mention below? I
know a penny-pinching mad scientist type that would be interested in
the challenge of building on of these.

On Wed, 17 May 2006 12:20:10 -0400, "Glenn Ashmore"
wrote:

At one time Spectra had an exploded parts sketch and a parts list with all
the o-ring dimensions that was enough to reverse engineer it but I think
they took it down after I pulled out my calipers at Annapolis a few years
ago to get a few last dimensions. :-)

--
BRENT - The Usenet typo king. :)

Energy Recovery (Clark Pump) Water Maker Pumps?
 

On Fri, 19 May 2006 21:12:46 GMT, Brent Geery
wrote:

Hi Glenn,

Do you happen to still have a copy if the info you mention below? I
know a penny-pinching mad scientist type that would be interested in
the challenge of building on of these.

On Wed, 17 May 2006 12:20:10 -0400, "Glenn Ashmore"
wrote:

At one time Spectra had an exploded parts sketch and a parts list with all
the o-ring dimensions that was enough to reverse engineer it but I think
they took it down after I pulled out my calipers at Annapolis a few years
ago to get a few last dimensions. :-)

PS Sorry for the top post. I intended for this message to go via
email!

--
BRENT - The Usenet typo king. :)