DIY CO2 pressure or flow regulator

[ukedude]

I made a previous posting regarding a DIY CO2 generator generating enough pressure for use on a canister inflow or outflow reactor.

Another related question is regarding a regulator that would allow me to adjust the amount of CO2 injected into the system.

Assuming (and this is a big assumption) that I can maintain a pressure at least high enough to get the system to function, I may find that I am pushing too much CO2 into the tank (a 29-gal).

Has anyone had success using any particular regulator valve to adjust the flow of CO2?

My plan is to use a DIY bubble counter (a 16 or 20 oz. pop bottle--see http://www.qsl.net/w2wdx/aquaria/diyco2.html#3). I think the bottle used as a gas separation device could also be used as a bubble counter if I put water in the bottle.

Since would be able to measure the bubble count, I would want a way to control it.

Would a simple air pump regulator valve be sufficient?

 

[Purrbox]

The problem is that if you restrict the flow to much you could end up with a really nasty mess. DIY CO2 generators can explode if the pressure gets to great for the bottle. Since this has been known to happen with just getting some gunk from the bottle into the tubing, I wouldn't even think about restricting the flow.

The way to adjust the amount of CO2 flowing to the tank, is by adjusting the number and size of bottles you are using to generate CO2 or playing with the CO2 mix. If you want a greater level of control you really need to make to jump to pressurized.

 

[ukedude]

Perhaps it just isn't worth going farther down this path, but I know there are pressure relief valves that can be calibrated to a maximum pressure before they bleed off excess gas.

Perhaps those are too expensive or cumbersome for such a system as this--why bother when you can just by the tank and regulator and be done.

Is there such a thing as an air line relief valve for hobbyists? I have seen blowout relief valves that release all pressure from the system (by blowing off a rubber cap, for example), but none that bleed off only excess pressure.

Out of curiosity, at what pressure (in PSI) do DIY systems run. How about bottled systems?

 

[malkore]

I'm unaware of any relief valves that'd work with the low pressures associated with DIY CO2.

on a pressurized CO2 setup, the needle valve dials down to around 4-5psi on average. I would guess DIY is probably 3psi on average.

I guess I'd look for a 10psi pressure valve.

that said, its uncommon for people to get too much CO2 from a DIY setup.

 

[Zezmo]

I tried using a needle valve to bleed off excess. It was less than successful.

 

[hashbaz]

If there there is no pressure restriction (like a valve or airstone) then the pressure of your CO2 system would depend only on how deep in the tank the CO2 outlet is. 1 foot deep = .43 psi; 2 ft deep = .46 psi

I would guess that you would have a very hard time finding a valve that works this low.

This is part of the reason that I like bell diffusors - any "extra" CO2 floats to the surface.