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Re: Aquatic Plants Digest V2 #944



>From: "Dixon, Steven" <stdixon at bechtel_com>
>Subject: Nupro Needle Valves
>
>I was looking for a supplier for the Nupro B-4MG2 needle valve for a new
>setup and noticed on George's site that he had been trying to track down
>sources as well.
>
>Nupro valves are made by Swagelok.  Swagelok has a nifty web site at:
>
>http:\\www.swagelok.com

If the B-4 series is like the valve shown at

  <URL: http://www.swagelok.com/WhatWeDo/Valves/Needle/index.htm >

then it might not do the job.

You will need a 'metering' valve like the S-series shown at:

   <URL: http://www.swagelok.com/WhatWeDo/Valves/Metering/index.htm  >

The one I use is the SS-SS4-OH, I believe.

The important factor is the Flow Coefficient which is 0.004 for the
valve I use. That is when the valve is fully opened. I use it with
just a few turns short of closed, so I'm guessing the flow coefficient
is about 0.001. I my setup, I have a 20 lb. tank with an L-Tec
R-5007-GS-580 regulator. This reduces the 1200 psi tank pressure to a
much smaller value (is it 45 psi? I forget). Following this is a
3-way needle valve like the B-series for a special outlet, and then
the solenoid, and finally the Nupro S valve.

I am basing this on a graph from a Nupro bulletin  N-1189-1 from
November 1989. There is perhaps more up-to-date information now.

That special valve I use it for bulk transfer of CO2 gas to something
like a Bell jar (or I used to, I don't use it at all any more).

As you can gather, my information is rather old, since I did my
research in this area about 6 years ago.

[...]

>Yesterday, someone mentioned getting more control over a CO2 setup with
>a controller.  I wonder if that is really necessary.  With a decent KH
>and a good needle valve there isn't much of a pH swing at night and the
>only thing I can think of to go wrong is a power outage.  Any opinions?

If I read you right, you have a valve that can be constantly open
when the voltage is out.

I think if you want this to work during a power fail you'd better
adjust the valve to work when power is out - then the flow will be so
low you may as well not even use a solenoid.

Personally, I feel a lot better using a controller, then I can set the
CO2 flow and pH more optimally.

-- 
    Jim Hurley         mailto:hurleyj at arachnaut_org
 Arachnaut's Lair    <URL: http://www.arachnaut.org/ >