54
7 Appendix
7.5
Sensors
Note:
Probes increase the stated response times.
7.5.1
Gas-sensitive semiconductor (SC) for H
2
Measuring range
0.0 – 10000 ppm (1 % vol.)
Resolution
1 ppm / 2 ppm / 20 ppm / 200 ppm
Response times
10 ppm H2:
tR < 1.2 s
t50 < 6 s
t90 < 18 s
100 ppm H2:
tR < 1.0 s
t50 < 7 s
t90 < 15 s
tR … Time until device’s first response following
delivery of gas
Warm-up times
up to 5 min
Measuring error
30 % (short time)
Interference
at 20 ºC:
1 % vol. CH4
50 ppm maximum
1 % vol. C3H8
10 ppm maximum
40 ppm CO
2 ppm maximum
1 % vol. C2H6O (ethanol)
2 ppm maximum
3500 ppm benzene
10 ppm maximum
Water vapour, < 80% r.h.
< 1 ppm typical
Lifetime, expected
5 years
7.5.2
Thermal conductivity sensor (TC) for H
2
Measuring range
0 – 100 % vol.
Resolution
0.1 % vol.
Response times
t50 < 3.1 s
t90 < 6.5 s
Warm-up time
< 30 s
Measuring error
3 % of measuring range end value
Interference
to all gases with a different thermal conductivity
Lifetime, expected
5 years
