Hydrogen leak testing
The hydrogen detection is used as a standard for testing a hydrogen over- pressure vessel or installation for leaks and defects. This is important, since the hydrogen concentration of 4% to 75%, mixed with air (about 40,000 ppm), may be explosive.
- 2.1 Room Monitoring
- 2.2 Monitoring in manufacturing facilities
- 2.3 Portable meter
Sensor types
Hydrostatic test
The hydrostatic test. Here, the apparatus having a virtually incompressible liquid, usually water or oil filled and tested by charging the apparatus with a pressure deformation and leakage. Are usual here 150 % of the rated pressure to have a certain margin of safety.
Helium leak test
In the helium leak test, the apparatus is flushed with helium as a test gas, the lightest inert gas and a vacuum to the apparatus around. Read their tightness with a helium detector, the smallest concentrations (1:10 000 000 particles ) can be measured, tested. In this method one uses the advantageous property of the helium to escape even through the smallest cracks, from.
Hydrogen micro sensor test
The so-called hydrogen micro sensor test, the apparatus is flooded with a test gas mixture of 95% nitrogen and 5% hydrogen. This low concentration of hydrogen is required as a hydrocarbon mixture containing less than 5.7 volume percent hydrogen is non-flammable. The plant is now checked using a micro-electronic handheld sensor on escaping hydrogen gas. This sensor can detect Wasserstoffleks with a minimum flow rate of 5x10- 7 cm ³ / s. Advantage of this method is compared with the helium leak test much lower cost. In addition, the calibration gas used is cheaper than helium.
Uses
Room monitoring
Since hydrogen is the element with the lowest density, it rises. Thus comes into the room monitoring a stationary measuring instrument is used, which is installed at the highest point in space at which hydrogen could accumulate.
Monitoring in manufacturing systems
Permanently mounted sensor, which is used in production lines and other industrial installations.
Portable meter
A lighter -weight, portable instrument having a sensor that works with point contact.