水素イオンセンサ

抄録

Hydrogen behavior in air is still mysterious when it’s emitted or leaked from orifice. Hydrogen might diffuse quickly and reach to the level lower than lower explosion (LEL) limit immediately. Hydrogen molecules diffuse quickly as individual or form clusters with others. But if there is obstacle to diffuse hydrogen, it might stay at the rather high concentration under the ceiling as a cloud. Real time and direct analysis hydrogen sensor in pin point 3-D monitoring was challenged by electron impact ionization with direct sampling system(Direct analysis).

In ion sensor, sample gas was introduced from sniffer probe through narrow silica capillary tubing with nonpolar inner treatment. Water absorption and adsorption on the surfaces in sensor system was prevented by applying chemical treatment on metal surfaces and heating. Then hydrogen sample was directly injected to differential pumping stages to ion detector through ionization cell. Output signal kept linear relation in hydrogen concentration of 0.1-100% range. Repeatability and long term stability experiments were also performed and showed excellent stability.

Several hydrogen sensors were tested by hydrogen emission. The results at initial sampling start and final sampling stop performance after cut introducing hydrogen were compared. In 3 dimensional hydrogen emission and combustion test, the H2 concentrations were checked in real time and direct analysis.