Oxygen flow meter

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  An image showing the internal flow path of the oxygen regulator

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  A printed version of the most up to date the oxygen regulator

What it does

A 3D printable oxygen metering device that would allow the care-giver to set the pressure on the bottle of oxygen and know how much oxygen they are getting.

The concept is similar to an orifice flow metering device, where if you have an orifice that the flow moves through of a set diameter and you know what the pressure drop is across that diameter you can infer the flow rate.

To prove the concept we started with a flow rate of 10 litres per minute and pressure drop across the orifice of 1 bar. So if the flow regulator is set to 1 bar you should get 10 liters per minute of oxygen. These variables are used in a set of equations to give an orifice diameter.

How we built it

Currently the devices have been printed in PETG on a Prusa Mini using a 0.25 mm nozzle and then using a pin vise the orifice is drilled out to 0.8 mm in diameter.

Challenges we ran into

The resolution of that orifice diameter was a challenge, we tried 0.4 mm nozzles, 0.25 mm nozzles and eventually resorted to drilling them out.

What's next for Oxygen flow meter

Testing! We need to test that we are achieving the flow rate, which will involve a compressed air source and a rotameter as well as some pressure gauges. We would also like to use some gauge pins to double check the diameter after drilling, as drills as small and flexible as these can be a challenge.

Built With

• shapr3d