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Check Valves & Manifolds for multiple tanks



I'm still waiting for Wright (or someone else) to explain his use of a check
valve to "regulate" the flow of CO2. I continue to believe that his
description was either mistaken or not fully described. A check valve does
not "regulate" anything - it is used purely to prevent the backflow of a
second fluid (gas or liquid) into sensitive equipment (needle valves,
regulators, CO2 cylinders).

As for Dwight's remarks regarding the use of manifolds for feeding CO2 to
multiple tanks, there are several ways you can go about doing this. The
ready made one that he sells from Aquarium Landacapes appears to be an
elegant solution (i.e. fewer individual parts) to the problem. As far as I
can tell (I've not seen one "in the flesh"), they are building these from
components more than likely sourced from Clippard Instrument Laboratory in
Cincinnati. They carry a variety of fluid control products and in their
Minimatic product range there are several drilled bar stock pieces which
could be used as the basis for a very workable CO2 manifold. It is merely a
piece of aluminium bar stock which has been drilled and tapped to accept any
number of valves and fittings. An enterprising hobbyist could quite easily
use one of these and incorporate the needle valve(s) of their choice. For
the "luxe" crowd, I would probably recommend either HOKE Micro-mite ($$$) or
Milli-mite (less $$$) metering valves or the Parker HR series metering
valves (also $$$). Using multiple Parker HR's or Hoke Micro-mites is going
to get VERY expensive, but would offer a "Rolls Royce" ride. A cheaper
alternative would be to use either Nupro S valves (M3's higher priced
metering valve is a Nupro S, I believe) or even the Nupro M.

There are other companies selling these pre-drilled bar stock manifolds -
they are available in aluminium, stainless steel or brass, and range in
price from $5.00 - $60.00 (this is just the bar, it doesn't include the
needle valves or the connection fittings).

The largest part of the "cost" of one of these systems would be the needle
valves, as the "manifold bar stock" is not expensive.

All of these valves are readily available with a wide variety of connection
sizes and it should be a simple matter to adapt them to work on a Clippard
bar stock manifold. Unused ports on the manifold bar stock can be capped off
with plugs and this would also allow for future expansion of the system. The
hardest part of all of this would be to ensure that the connectors that you
use will physically allow you to make the connections easily and tightly
(there isn't much space to screw in a valve when the hole spacing is only
around an inch apart).

Another alternative would be to check out Swagelok fittings - they make a
multitude of individual "pieces" which could be put together "Tinker Toy"
style. These individual pieces tend to be pricy though, and this would add
considerably to the cost of the manifold system..

James Purchase
Toronto