High-precision density sensor for concentration monitoring of binary gas mixtures

We developed an in situ multi-sensor system for measuring the composition of a binary gas mixture. The sensor system simultaneously measures pressure, temperature and density from which the partial pressure of the individual gas components can be deduced and monitored online. In order to achieve highly precise concentration determination, the key component of the system, a microcrystal density sensor, is temperature-compensated and calibrated enabling an error reduction of more than one order of magnitude. We show application of the sensor system for the exemplary case of monitoring binary mixtures in gas-insulated electrical installations and demonstrate that our measurement system achieves a concentration determination accuracy of better than Δc < ±1%-point over a large temperature range.