In a hospital, the oxygen pipeline pressure is approximately 3,7 to 4,5 bar. Another source of oxygen can be an oxygen concentrator where the pressure would be about 1,5 bar.
GOAL
Measure the flow of oxygen on the different available pressures and different hose lengths. And finding suitable flow restrictors if necessary to reach a flow of 100 to 150 l/min.
Setup
By placing a Fluke VT900A between the gas regulator and the machine it is possible to measure the flow of oxygen. The flow restriction was made by pinching a tube. To pinch the tube consistently 3D-printed spacers were used. In this test, the thickness of these spacers is varied to determine the thickness that best complies with the needed flow of the machine (100-150 l/min).
Measurement
| Pressure (bar) | Flow restrictor thickness (mm) | Flow 4 meter hose (l/min) | Flow 1 meter hose (l/min) |
|---|---|---|---|
| 5 | No restrictor | 250 | 325 |
| 3 | 220 | 285 | |
| 2,5 | 156 | 176 | |
| 2,4 | 150 | 169 | |
| 2,3 | 129 | 130 | |
| 2,2 | 109 | 117 | |
| 2,1 | 82 | 85 | |
| 2 | 11 | 33 | |
| 2 | No restrictor | 120 | 195 |
| 3 | 110 | 154 | |
| 2,5 | 77 | 90 | |
| 2,4 | 75 | 82 | |
| 2,3 | 66 | 71 | |
| 1.5 | No restrictor | n/a | 80 |
Results
Tests should be repeated since later research showed that pressure of oxygen concentrators is 1,3 bar as opposed to the 1,6 bar that was first believed.
For use at 5 bar a 2,3 mm spacer was used to bring the flow down to 130 l/min.
