Performance Analysis of Relative Humidity Factor and CH4 Concentration Measurements for NDIR Gas Sensor

Non-dispersive infrared (NDIR) gas sensors can be adversely affected by changes in temperature and relative humidity if not properly designed in hardware and software. High relative humidity causes the NDIR gas sensor to give erroneous readings. Fault readings cause false alarms. While false alarms reduce sensor reliability; may disrupt process operations in the systems used; can cause costly losses. In this article, studies have been carried out on the use of hydrophobic physical filters, which is one of the methods of reducing the effect of fault readings of NDIR gas sensors at high relative humidity. The adequacy of a physical filter and the features to be considered when using a physical filter are mentioned. In this context, first, the effect of ePTFE model number BX-BAE-001 on the sensor performance at high relative humidity was investigated. Next, experiments were performed on different two ePTFEs with different pore sizes and airflow rates.