NOx Sensors for Harsh Environments
There is a need for the development of sensors that are low-cost, fast, reliable, rugged, selective and sensitive for automotive and power industries. Miniature gas sensors are needed for in situ monitoring in harsh environments for efficient emissions control. In many industries the monitoring and control of combustion products is a top priority. Accurate measurement of emissions from combustion processes will lead to better control and reduction of toxic gas emissions. To address this issue Holt Scientific is developing nano-spinel catalyst materials to improve NOx sensor selectivity and durability.
High Temperature Thermistor Materials for Industrial Applications
Of all the various sensors used to monitor industrial processes, thermal or temperature sensors are in the highest demand. Precise temperature control is critical for advanced technology. There are numerous types of sensors used to monitor temperature including; thermocouples, resistance temperature detectors (RTDs), optical and thermistors. Thermocouples while used in a wide range of machinery, suffer from issues of slow thermal response time and low sensitivity. Metallic RTDs suffer from the same issues. Optical infrared based measurement systems while providing fast thermal response time are not as competitive on a cost basis and the materials used for the active sensing elements will not survive harsh environments found in most industrial processes. Thermistors on the other hand provide a low-cost highly sensitive device that can be mass produced easily via thick film batch processing. Thermistors have found application in environments where highly sensitive temperature measurement is required ranging from medical (ie. cardiac output) to aerospace (turbine exhaust). Standard NTC materials based on spinels of nickel, cobalt, manganese, and chromium suffer from aging when used in excess of 200ºC.
