Re: CO2 flow meter

Miles Morrissey wrote:

> I just talked to a industrial gas supply store and the guy there
> told me from what he understands about what I'm trying to do,
> I don't need a regulator and needle valve but a flow meter.
> This will regulate the pressure in the tank and reduce the flow 
> to the very low rates I require.  Does this sound right to people??

I believe the flow meters are used in welding applications
where an inert gas is required to prevent oxidation of the hot
metal. The flow rates are much higher than those required for
aquaria. When I was making inquiries, the price for these things
was quite high and comparable to that for regulators. Most
regulators with gauges are designed for compressed oxygen
and the welding supply guy told me that the acidic CO2 gas
will corrode them. A gauge won't tell you much because
compressed CO2 is a liquid with a constant gas pressure (for
any given temperature) and this won't change until the
the liquid CO2 in the tank is all gone. From that point it
is a very short time before you need to re-fill the tank.
I don't have bottled CO2 (relying upon the little yeasties)
but I think many people keep a second smaller 5 lb bottle
on hand while they take their larger one in for a refill.
This also gives you the flexibility of having several days
before you need to make that emergency trip for more CO2. :-)
It also saves you money on useless, corroded pressure guage.

The high tech system would include a tank (and spare backup),
regulator, high quality needle valve, solenoid control valve
and electronic pH controller.

A low cost system would include a tank (possible spare),
FROG regulator, needle valve and human pH controller.
To forestall questions about FROG regulators, here is a quote
from the plant FAQ:

 "Mixed in amongst the plaid caps and kinky leather face
 masks was a "FROG" - Flow Regulated Orifice Gauge. It is a preset
 regulator for CO2 tanks that is set to 22 PSI. It has a little
 button that either pops out or retracts when the tank is almost
 empty (but does not function very when used with the low flow
 rates in aquaria). This would be an inexpensive way to get setup
 with a more capable CO2 system. It was marked $22 and is made by
 Western (Model RP22320). You can call Western directly at
 216-871-2160 to find a local distributor."

The FAQ has a lot more suggestions on DIYS CO2 systems and
is worth reading. BTW, I had no idea that the interests of
our group are so diverse; african violets, chains, velcro
and leather straps, face masks... [tee-hee] ;-)

Steve (encouraging members to quote their city & location
with their sig) in Vancouver where it's STILL raining.
Karen, send us your snow PLEASE! (frustrated skiier)