How to calculate volume HFC's or other propellant liquid in a aerosol can

Not to apologise for your English. It's excellent... You are dealing in multiple unknowns, 2 more-or-less homogeneous volumes with unknown densities. A simple way would be to (1) weigh the full can; (2) release all the gas (or the volatile liquid that generates the gas), and (3) measure the weight and volume of the remaining liquid. Then with the knowns, you can write a generic formula.

It is probably proprietary information since the amount of propellant required ties directly into their cost to produce. I think Cardio is right and you will have to do some home experiments if you really desire to find this out.

Thanks for the answers. I can try the test, but I think you are right about the differency of the weight of several product. I just heard someone siad that propane/butane would take 37% of the total volume and CO2 just 3% and therefore much better for the customer and have more volume then the propane/butane propellant. That's why I asked.

if your aerosol can is filled with a liquefied gas eg. propane no HFC's are required

if a liquid like hair spray, weight the container then the liquid balance = HFC gas

you may have to make a small hole at top of container to let out only HFC weight difference HFC

Hi all,

Sorry for the delay, but I was in my Easter hollydays.

First of all a question: Do you want a formula to calculate the volume ratios for manufacturing aerosol cans? If this is the case I suppose that depends on the specific components (propellant and propelled).

If you just need to measure the relative volumes of liquid and gas there are external ultrasonic level meters that can give you the liquid height on the can. It's a question of simple geometrical calculations to get the volume ratio.

The question is how to compare butane/propane with CO2 as use as a propellant. Is it possible that you only need 3% CO2 instead of 37% butane/propane in a liquid form in say as example in a 400 ml aerosol can. The product can be hairpspray or a lubricant or a glasscleaner.( bruto maybe 500 ml)?

Sorry, I didn't understand (read) completely your second post.

I'm not an expert on aerosol cans, but just considering thermodynamics, the volume of the can is constant, say 500 ml, if initially you have 37% of butane/propane in liquid form, must be in equilibrium with the small volume not liquid filled (filled with the propellant gasified).

Without doing any calculation I don't think 3% CO₂ could have the same propellant capacity as 37% of liquid hydrocarbon, provided you have mentioned "volumes" and considering the pressure rating of the can the same in both options.

If you are going to perform tests surely the results will confirm that. Furthermore, from the safety point of view, I think CO₂ is preferable to any pressurized fuel.

Sorry I was bound to other problems so that I am a bit late.

Before you can make an estimation you should know the pressure you need in order to make the spray nozzle work ok.

Second you should know if your propellant will go as solution into the stuff you want to spray.

The spray action is quite fast so that an adiabatic expansion could be considered as a 1st approximation.

The spray minimal pressure must be guaranteed for the whole volume you want to spray.

You can make an equation connecting the propellant volume at full bottle and at empty bottle and set that for the empty bottle you should have still the right pressure and for the full bottle the pressure must not exceed the admissible pressure for the container. The difference between the 2 volumes is the volume occupied by the stuff you intend to spray.

The solution is more complex if the propellant can be solved by the spray.

Try first with this approach it is straight.