Testing Technology
Leak rate
The term leakrate ql with ist unit (mbar × l)/s is used to declare a leakage.
ql= (∆p ×V)/∆t
It corresponds to a change of gas volume per time unit.
The leakrate of ql=1 (mbar ×l)/s is given, if in a closed container with a volume of 1 liter the pressure rises or falls by 1 mbar within 1s.
Conversion of leakrates
| Tn=0°C Pn = 1013mbar | mbar*l/s | cmE3/s | cmE3/min | Pa*l /s | Torr*l/s |
| mbar*l/s | 1 | 9,87E-1 | 5,92E1 | 1E2 | 7,5E-1 |
| cmE3/s | 1,01 | 1 | 6E1 | 1,01E2 | 7,6E-1 |
| cmE3/min | 1,69E-2 | 1,67E-2 | 1 | 1,69 | 1,27E-2 |
| Pa*l/s | 1E-2 | 9,87E-3 | 5,92E-1 | 1 | 7,5E-3 |
| Torr*l/s | 1,33 | 1,32 | 7,9E1 | 1,33E2 | 1 |
Example:
1 mbar•l/s = 59,2 cm3/min or 0,0169 mbar•l/s = 1 cm3/min
Relation between leakrate and leak-dimension
| Diameter leak | Leakrate {mbar*l/s] |
| 1 cm | 10E4 |
| 1 mm | 10E2 |
| 0,1 mm | 10E0 |
| 0,01 mm | 10E-2 |
| 1um | 10E-4 |
| 0,1 um | 10E-6 |
| 0,01 um | 10E-8 |
| 1 nm | 10E-10 |
| 1 Anström = 0,1 nm | 10E-12 |