Creating a 2 stage pressure regulator

I have a nitrogen tank and have been using an oxygen single stage regulator and argon flowmeter with it to keep gas flow constant at about 10-15 litres per minute. My question; Does using a flowmeter automatically turn a single stage regulator into a two stage regulator such that when tank pressure starts to decrease from 200 bar, the gas flow rate will stay constant at what I have set it to with the flowmeter?
Reply greatly appreciated.

from what I understand, no. a flowmeter simply indicates what the output flow is.

If you have a flowmeter with a control valve, then it simply takes the input pressure and restricts gas movement to maintain flow rate. If pressure changes, so will flow rate, there is no regulation.

Minbari said:

from what I understand, no. a flowmeter simply indicates what the output flow is.

If you have a flowmeter with a control valve, then it simply takes the input pressure and restricts gas movement to maintain flow rate. If pressure changes, so will flow rate, there is no regulation.

Click to expand...

^that's correct. a flowmeter does just what it says--regulates flow...at whatever pressure is coming in to it.

Ok... well then will a single stage regulator keep a constant level of flow when the pressure in the tank decreases?

gametheory said:

Ok... well then will a single stage regulator keep a constant level of flow when the pressure in the tank decreases?

Click to expand...

depends on how good the regulator is. a regulator that doesnt flow very well will not regulate no matter what you do. Most will be fine with at least a 10% head pressure above the set point. Obviously once your tank pressure gets at or under the set point, it cant regulate at all anymore. (will just be bottle pressure)

If you need more precise pressure regulation, then a second stage can help, as long as the set points between the two are far enough apart.

as an example, a two stage co2 or N2 setup would be bottle pressure --> 500psi --> 12psi. by the time you get under 500 Psi, you are basically empty, but the second stage will continue to regulate. I dont know what the pressure is in the oxygen bottle.


What is the application? if it is just oxygenating wort, I am not sure precise flow rate is critical.

Yeah it seems that level of precision is unnecessary. Thanks for replies.