Re: [APD] Setting up CO2 needle valve

["S. Hieber" <shieber at yahoo_com>]

This won't deserve posting for posterity, but here goes:

The Swagelock is a very good valve. Not made for shutting a
flow off but only for limiting the flow. But it is precise,
well made and looks and feels like it, especially when you
turn the knob. You mount it on the CO2 line *after* the
regulator and before or after the solenoid, depending on
which is easier to do.

Is that 1/4" tube?

The insert is part:  B-405-3 Brass Insert for Tubing, 1/4
in. OD - 3/16 in. ID


Go to swagelok.com and in the part# box enter B-405-3 and
press enter.

The valves used to come in several ways, with diff kinds of
fittings. Now, the usual is the fitting that requires a
small insert in each end of the tubing, which gets squished
when the fitting is closed. It's hard to reuse these
inserts, so I usually buy a bunch when I need to buy any.
They are now 60cents each. Since Swagelock usually sells to
commercial outfits/contractors who would have a boxful of
these on hand, they don't pack them in with the valves,
which is a bummer for folks like us because we don't know
we need to order them when we order the valve.

With soft tubing, like vinyl, you need the insert so that,
when the nut presses down on the outside of the tubing, the
tubing doesn't collapse but instead provides resistance and
a good seal. I doubt Homedepot and the like sell inserts
alone but Homedepot's universal-compression fittings are
usually a kind that come with a similar metal insert for
tubing.

To find out how they will charge for shipping you a few
inserts, you have to call or use the ask-for-a-quote
feature on the web page. Depending on how much Swagelok
wants for shipping you a few inserts, it might be cheaper
to buy an unneeded fitting at Homepdepot just for the
inserts. ;-)

Or you might get some substitute metal tubing and cut a
small piece to use in place of the insert, in a pinch. Try
it and put some soapy water on it to see if it leaks when
put under pressure. Wiggle the tubing a little and if it
still doesn't leak, you're home.

Before you install the valve turn the knob clockwise gently
until you can feel it bottom out. Don't close it hard --
this is just to get a feel for what it's like to hit
bottom, so to speak. Then turn it back counterclockwise a
quarter turn to ensure the the needle inside is *not*
bottomed out and won't get damaged during installation if
the know gets bumped.

Once you have it installed, turn turn the knob again almost
all the way down. As soon as it touches or almost bottom,
stop, don't force it any farther. Turn your regulator for
about 10 psi output and back out the valve until you get
the flow you want. You probably will have to go back and
forth between the valve and the regulator to get a balanced
setting that works. You might end up and 10 psi or 30 psi,
depends on your setup, desired flow, and the accuracy of
your regulator meter. It's not all that important except
that you want to have the metering valve as close to closed
as possible and still allow the desired flow. Otherwise,
the regulator is controlling the flow and the metering
valve is just an expensive ornament.

>From then on, you can leave your regulator setting alone
and you can fine tune/adjust flow by adjusting the valve in
small increments, maybe a 1/16th of a turn at a time.

Hope that helps.
Scott H.
--- Jade Rubick <jade at rubick_com> wrote:

> On the advice of people here, I purchased a CO2 needle
> valve (B-SS4 
> FINE METERING VALVE, 1/4" by Swagelok).
> 
> However, I'm completely at loss as to how to set it up.
> Does anyone 
> have any advice on it?
> 
> It seems like a "compression fitting(?)", but I thought
> you had to put 
> something in the tube to make that work?
> 
> Could someone help me with this? I'll put your reply on
> the web for 
> posterity! :)

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