# Liquid CO2 Volume\Weight Measurment in Cylinder

Hello,

I have been working on a personal project involving the transfer of liquid CO2. I want to figure out a way to measure the transfer of liquid CO2 from one cylinder (supply cylinder) to another (receiving cylinder) and get an exact measurement of how much CO2 was transferred into the receiving cylinder. I am interested in finding out if there is a way to determine the volume of liquid CO2 in the receiving cylinder by using pressure measurements. For example, if I know a certain volume of CO2 in a fixed size container produces a certain pressure measurement can I say that every transfer of liquid CO2 into a similar cylinder will produce the same volume, assuming all conditions are the same? Any direction is appreciated.

Parameters:
1. I do not want to use a flow meter as they are very expensive.
2. I do not want to use a weight scale as I already used that method.
3. For this experiment I want to transfer 16oz of liquid CO2 from the supply cylinder to the receiving cylinder.
4. Let’s assume the supply tank is a standard 50lb Dip Tube CO2 liquid supply cylinder.
5. Let’s assume the receiving cylinder is initially empty.
6. Lest assume the receiving cylinder is rated for max 20oz capacity.
Any direction is appreciated and if you have any further questions let me know.

Regards,

David

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Nidum
Gold Member
A device commonly used for plain liquids is the measuring chamber . An intermediate cylinder of known volume is first filled from the main cylinder and then discharged into the receiver cylinder .

Hi Nidum, Thanks for your reply. I am looking more for calculations to determine Volume of CO2 at a given pressure for a given amount and/or Pressure of CO2 at a given volume for a given amount using a fixed container size assuming that the CO2 is always in liquid state.

As long as you have liquid CO2 in that container, the pressure of the CO2 vapors will be the so called "equilibrium vapor pressure" which depend on the temperature but not on the amount of liquid.
However, you also have some contribution from the air left in the container. When you say "initially empty" I believe you mean full of air and not vacuumed, right?
Now, if this air cannot escape from the second container as you fill it up, the air pressure will increase as you add more liquid. If this is the case and if you can separate the contribution of air pressure from the total pressure, you may be able to use it to estimate amount of liquid.
But you will need to know the equilibrium vapor pressure at the temperature inside the container.