TY - CONF A1 - Tiebe, Carlo A1 - Detjens, Marc A1 - Banach, Ulrich T1 - Messunsicherheiten von Feuchtesensoren N2 - Inhalt dieses Seminarbeitrags sind Hygrometer und Kenngrößen der Hygrometrie, Anforderungen an ein Prüflabor sowie die Bestimmung der Messunsicherheit bei der Prüfung von Feuchtesensoren wie auch Prüfung auf signifikante Abweichungen. T2 - 308. PTB-Seminar Berechnung der Messunsicherheit – Empfehlungen für die Praxis CY - Berlin, Germany DA - 15.03.2018 KW - Messunsicherheit KW - Feuchtesensor KW - Prüflabor PY - 2018 UR - https://www.ptb.de/cms/fileadmin/internet/fachabteilungen/abteilung_8/8.4_mathematische_modellierung/308._PTB_Seminar/Vortraege/4PraxisII/Messunsicherheiten_von_Feuchtesensoren.pdf AN - OPUS4-44546 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Detjens, Marc A1 - Tiebe, Carlo A1 - Banach, Ulrich A1 - Ritter, U. T1 - Ionische Flüssigkeiten als neuartige Sensorbeschichtung für coulometrische Spurenfeuchtesensoren N2 - Die Arbeit präsentiert erste Messungen mit coulometrischen Sensoren, die mit einer ionischen Flüssigkeit beschichtet sind. Diese Sensoren werden in der Industrie verwendet, um die Spurenfeuchte in unterschiedlichen Gasen zu messen. Normalerweise erfolgt eine Beschichtung der Sensoren mit Phosphorpentoxid und dessen Hydrolyseprodukte. In dieser Arbeit wurde stattdessen eine hygroskopische ionische Flüssigkeit benutzt. Die generierte Gasfeuchte für die Untersuchungen betrug bezogen auf die Frostpunkttemperatur -80 °C bis -30 °C, was gleichbedeutend mit einem Wasserdampf-Stoffmengenanteil von 0,5 μmol·mol-1 bis 376 μmol·mol-1 ist. Zusätzlich zu der Messung mit coulometrischen Sensoren erfolgte eine Referenzmessung der Gasfeuchte mittels eines Taupunkthygrometers. Erste Ergebnisse haben gezeigt, dass es möglich ist mit dieser Art der Beschichtung unterschiedliche Gasfeuchten zu messen. Aber es ergaben sich trotz gleicher Feuchte unterschiedliche Signalintensitäten bei den benutzen Sensoren und es zeigte sich eine Drift des Sensorsignales. T2 - Sensoren und Messsysteme CY - Nuremberg, Germany DA - 26.06.2018 KW - Spurenfeuchtemessung KW - Sensorbeschichtung KW - Elektrolyseverfahren KW - Ionische Flüssigkeiten PY - 2018 SN - 978-3-8007-4683-5 SN - 0932-6022 SP - 520 EP - 523 PB - VDE VERLAG GMBH CY - Berlin, Offenbach AN - OPUS4-45319 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Detjens, Marc A1 - Tiebe, Carlo A1 - Banach, Ulrich A1 - Ritter, U. T1 - Ionic Liquid Based Coulometric Trace Humidity Sensors N2 - This work presents a first attempt to use ionic liquids as a new coating for planar coulometric sensors. These sensors are used for the measurement of trace humidity in various gases. Usually, the coating of the sensors is tetraphosphorus decaoxide and its hydrolysis products. Instead, a hygroscopic ionic liquid was used as sensor coating in this work. Generated frost point temperatures tf in the gas ranged from -80 °C to -30 °C, which is equivalent to vapour mole fractions xv from 0.5 μmol·mol-1 to 376 μmol·mol-1. In addition to the coulometric sensors, the generated humidity is determined by a precision dew point hygrometer as reference. First results show that it is possible to measure humidity with ionic liquid based coulometric sensors. T2 - ALLSENSOR 2018 CY - Rom, Italy DA - 25.03.2018 KW - Ionic liquids. KW - Coulometric sensors KW - Sensor coating KW - Trace humidity measurement PY - 2018 SN - 978-1-61208-621-7 SP - 13 EP - 14 PB - IARIA AN - OPUS4-44609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Detjens, Marc A1 - Tiebe, Carlo A1 - Banach, Ulrich T1 - Influence of Gas Pressure on Coulometric Trace Humidity Measurement N2 - Planar coulometric sensors were investigated in humidified synthetic air at various absolute gas pressures, i. e. 2 bar, 5, bar, 10 bar, and 15 bar. Humidified gas flow at adjusted gas pressure was split into two flows, one passed a coulometric sensor and the other one passed a reference hygrometer after decompression. Both signals were recorded and then compared after calculation of resulting frost point temperature. Calculation is based on a calibration function obtained at ambient pressure. Comparison showed that an increasing pressure resulted in a higher derivation between sensor signal (calculated frost point temperature) and reference frost point temperature. At an absolute pressure of 2 bar the differences were minor in consideration of the uncertainty, however at 15 bar the differences were 6.77 K. Nevertheless, it was possible to measure the gas humidity at higher pressure with coulometric trace humidity sensors. T2 - 17th International Meeting of Chemical Sensors, IMCS 2018 CY - Vienna, Austria DA - 15.07.2018 KW - Gas pressure influence KW - Coulometric sensors KW - Trace humidity measurement PY - 2018 SN - 978-3-9816876-9-9 U6 - https://doi.org/10.5162/IMCS2018/P2EC.7 SP - 715 EP - 716 PB - AMA Service GmbH CY - Wunstorf / Germany AN - OPUS4-45539 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Detjens, Marc A1 - Hübert, Thomas A1 - Tiebe, Carlo A1 - Banach, Ulrich T1 - Temperature influence on coulometric trace humidity measurement N2 - Planar coulometric sensors were tested in humidified synthetic air at various gas temperatures. Generated frost point temperature in the gas ranged from -30 °C to -60 °C and were measured by coulometric sensors and in addition by a calibrated dew point hygrometer. The gas temperatures, which were measured by a calibrated Pt100 sensor, were set to -20 °C, 0 °C, 23 °C, 40 °C, 50 °C, and 60 °C during the experiments. Empiric nonlinear functions were calculated between the generated humidity and the sensor signals. In comparison to the measured signals at 23 °C, the sensor signals were lower at the other gas temperatures. The measurements at 60 °C showed indistinct results due to a great signal noise. The response behavior of the sensors was similar at 23 °C, 40 °C and 50 °C. In contrast to that, the sensors reacted slowly at a gas temperature of -20 °C and 0 °C. In summary, with coulometric sensors it was possible to measure continuously trace humidity with an expanded uncertainty below 2 K. T2 - IEEE Sensors 2017 CY - Glasgow, Scotland, UK DA - 30.10.2017 KW - Response behavior KW - Coulometric sensors KW - Trace humidity measurement KW - Temperature influence KW - Chemical reaction PY - 2017 SN - 978-1-5386-4056-2 SP - 1308 EP - 1310 PB - IEEE CY - Piscataway, NJ, USA AN - OPUS4-43241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Detjens, Marc A1 - Hübert, Thomas A1 - Banach, Ulrich T1 - Spurenfeuchtemessung in unterschiedlichen Gasen mit coulometrischen Sensoren N2 - Die Messung der Gasfeuchte im Spurenbereich in unterschiedlichen technisch und medizinisch relevanten Gasen erfolgte mit Sensoren, die auf dem coulometrischen Messprinzip basieren. Die verwendeten planaren coulometrischen Sensoren wurden im Frostpunkttemperaturbereich von -70 °C bis -30 °C in synthetischer Luft, Wasserstoff, Stickstoff und Distickstoffmonoxid (Lachgas) untersucht. Als Referenz für die Messungen wurde ein Präzisionstaupunktspiegel-Hygrometer verwendet. Die Gasfeuchte kann mit Hilfe der Sensoren in allen untersuchten Gasen, aber mit geänderten Kalibrierfunktionen, mit einer erweiterten Unsicherheit von kleiner als 2,1 K bestimmt werden. Für die Messungen in unterschiedlichen Gasen muss also der Einfluss der Gasmatrix auf das Sensorsignal berücksichtigt werden. So ist zum Beispiel bei Messungen in befeuchtetem Wasserstoff, aufgrund von Rekombinationseffekten, ein signifikant geändertes Sensorsignal zu beobachten. T2 - Temperatur 2017 CY - Berlin, Germany DA - 17.05.2017 KW - Spurenfeuchte KW - Coulometrische Sensoren KW - Technische Gase PY - 2017 SN - 978-3-944659-04-6 SP - 247 EP - 252 AN - OPUS4-40293 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Detjens, Marc A1 - Hübert, Thomas A1 - Tiebe, Carlo A1 - Banach, Ulrich T1 - Coulometric trace humidity measurement in technical gases N2 - Trace humidity was measured by using miniaturized planar coulometric sensors in technical gases such as hydrogen, nitrogen, helium, nitrous oxide, and synthetic air. Frost point temperatures tf in the gases ranged from −60 °C to −30 °C, which is equivalent to a vapour mole fraction xv from 10 μmol mol−1 to 376 μmol mol−1. In addition, the generated humidity was determined by using a precision dew point hygrometer as reference. Nonlinear calibration functions were calculated that correlated electric current (sensor signal) and reference humidity. Parameters of functions were tested with one-way analysis of variances (ANOVA) to prove if all used sensors had a similar behavior in the same gas during experiments. Results of ANOVA confirmed that averaged functions can be applied for trace humidity measurement in nitrogen, helium, nitrous oxide, and synthetic air. The calculated functions were negligibly different for nitrogen, helium, and synthetic air. In humidified nitrous oxide, a minor change of parameters was observed due to lower electrical currents. In total contrast to that, the measured sensor signals were significantly higher in humidified hydrogen and each sensor required its own calibration function. The reason was a recombination effect that favoured multiple measurements of water molecules. Nevertheless, it was possible to measure continuously trace humidity in all tested gases by using coulometric sensors with an expanded uncertainty below 2 K (k = 2). KW - ANOVA KW - Trace humdity measurement KW - Coulometric sensors KW - Chemical sensors KW - Measurement uncertainty PY - 2018 U6 - https://doi.org/10.1063/1.5008463 SN - 0034-6748 SN - 1089-7623 VL - 89 IS - 8 SP - 085004, 1 EP - 8 PB - American Institute of Physics (AIP) CY - Maryland (USA) AN - OPUS4-45956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tiebe, Carlo A1 - Detjens, Marc A1 - Banach, Ulrich A1 - Hübert, Thomas T1 - Measurement uncertainty of coulometric trace humidity sensors N2 - Especially trace amounts of water vapour in gases can be reliably determined by coulometric trace humidity sensors. The principle of these sensors is based on water vapour absorption in a hygroscopic layer and its subsequent electrolytic decomposition. The calibration of sensors was performed in the humidity range, expressed as frost point temperature, from −30°C to −80°C . This range is equivalent to volume fractions smaller than 376 µL·L−1. Generated humidity was measured with coulometric sensors and a chilled dew point hygrometer that was used as reference. An empirical non-linear function was found between sensor signal and measured reference humidity. This function consists of two parameters with a measurement uncertainty. Both calibration parameters were checked by means of one-way analysis of variance. It showed that gas specific function can be used for humidity measurement in nitrogen, hydrogen, dinitrogen monoxide, compressed and synthetic air. It is possible to determine trace humidity in all tested gases with an expanded uncertainty less than 2.1 K (coverage factor k=2 ) regarding frost point temperature. KW - Trace humidity KW - Coulometric sensor KW - Measurement uncertainty KW - ANOVA PY - 2018 U6 - https://doi.org/10.1515/teme-2018-0031 SN - 0171-8096 VL - 85 IS - 12 SP - 746 EP - 753 PB - De Gruyter CY - Oldenbourg AN - OPUS4-45959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübert, Thomas A1 - Majewski, J. A1 - Banach, Ulrich A1 - Detjens, Marc A1 - Tiebe, Carlo T1 - Response Time Measurement of Hydrogen Sensors N2 - The efficiency of gas sensor application for facilitating the safe use of hydrogen depends considerably on the sensor response to a change in hydrogen concentration. Therefore, the response time has been measured for five different-type commercially available hydrogen sensors. Experiments showed that all these sensors surpass the ISO 26142 standard; for the response times t90 values of 2 s to 16 s were estimated. Results can be fitted with an exponential or sigmoidal function. It can be demonstrated that the results on transient behaviour depend on both the operating parameters of sensors and Investigation methods, as well as on the experimental conditions: gas change rate and concentration jump. T2 - 7th International Conference on Hydrogen Safety (ICHS 2017) CY - Hamburg, Germany DA - 11.09.2017 KW - Response time KW - Hydrogen sensor KW - Test facility KW - t90 value PY - 2017 SN - 978-88-902391 SP - 1251 EP - 1261 AN - OPUS4-47592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -