RE: Little Giant Pumps

[Tom Droege <tdroege@veriomail.com>]

Chris,

Thanks for the suggestions.

First about series vs parallel in water systems.  The parallel connection 
almost guarantees that the camera that has the greatest resistance will get 
no water flow.  The series connection makes sure that all the cameras get 
the same amount of water.  Once the flow is enough, there is a trivial 
temperature rise between cameras.  I have just made the mistake of running 
too long with an open tank (hint to Arne and Michael) and there been enough 
dead flies and Lady Bugs drop in to gum up the works.

I am using the laboratory equivalent of the quick disconnects that you 
mention.  Slightly more expensive, about $4 a side.  My idea was that since 
they (and the water tubing) hung on the camera motion I did not want to use 
garden hose sized fittings.  I may have to rethink this.  The ones I am 
using are plastic, and quite light.  But the same idea.

Once the system is closed and you get the air out of it, you can pump up 
and down 32 feet with no consequence.  A little air does create a problem, 
so you need a pump with enough lift to get it started.  Still, water 
systems make no sense to me.  They often hang up, and my logic tells me 
they should be doing something other than what they are doing.  Sigh!  More 
folk lore to learn.

I have gone to the water filters with paper filters.  You can pick your 
micron size.  This will be OK once I clean out everything and start with a 
clean system.

Tom Droege

At 10:56 AM 3/26/01 -0800, you wrote:

>Tom,
>
>Some ideas:
>
>What about replumbing so that the pump feeds a manifold
>and then each camera takes it's cooling water from the
>manifold.  This way there is no "down stream" camera.
>I know "manifold" sounds complex but in this context it
>is likely that manifold = 1/2 inch plastic "Tee" fitting.
>
>For you electrical enginerring types:  what I mean is to
>"wire" the cameras in parallel rather then series.
>
>One other idea.  My TASS Mk III water tank is elevated.
>I keep it on a stand on a bench.  the water level is
>seven feet off the floor.  The pump has less work to do
>this way.
>
>Also.  I have an open cell sponge filter on the pump intake.
>Very cheap and simple.
>
>You can get cheap, high volume quick disconects at
>Home Depot in the garden section.
>I've installed these on the garden hose I
>keep in front of the house.  They allow a lot more then
>a few gal/hr to pass and will hold back my 125PSI water
>pressure when disconnected.  About $5.00 each
>
>
>
> > -----Original Message-----
> > From: Tom Droege [mailto:tdroege@veriomail.com]
>
>
> > Sigh!  I have spent the last few hours with anti-freeze
> > dripping off my
> > chin.  Everything is on the floor and I have to crawl around
> > to fix the
> > water system.  I now have a bare trickle running through the
> > system.  It is
> > probably enough.  One does not need much.
> >
> > Let's see:
> >
> > Allow a 5 F rise through the system.  There is about 3 amps
> > max drawn by
> > the TECs.  This is 36 watts.  One has to get rid of this plus
> > the heat
> > pumped out of the cold side.  Let's guess 7 watts per camera.
> >  That is then
> > a total of 50 watts.  This is 170 btu/hr.  170btu/5F = 34 pounds per
> > hour.  At 8 pounds per gal this is 4 1/4 gal per hour.  Hmmm!
> >  I wonder
> > what it is.
> >
> > OK, I measured it.  I am getting 2.2 gph.  So the temperature
> > rise is more
> > like 10 F.  This means that the down stream camera is seeing
> > 5 F hotter
> > water than the upstream one.  This will cost 2.7 C over what
> > I could get
> > with higher flow.  2.2 gph is really just a trickle.
> >
> > The problem is those nice self sealing disconnects that I use
> > on the back
> > of the camera.  They do not have a very large orifice, and it
> > tends to get
> > clogged.  So take care.  I have reconnected the water filter
> > even though it
> > causes a pressure drop.
> >
> > I think I need a Medium Giant pump instead of a Little Giant.
> >
> > Tom Droege
> >
> >