Catalytic Gas Sensors & Factors Affecting Life Expectancy
Catalytic sensors are used for detecting combustible, or flammable gases, such as methane, propane and hydrogen. They are a safe and reliable combustible sensor technology that has been used for man..
The catalytic bead sensor, also called a pellistor sensor is the most common type of sensor for combustible gas measurement. A coil of platinum wire is coated with ceramic material which is in turn coated with a catalyst. The coil is electrically heated to a temperature that will allow it to burn (catalyze) the target gas. Flammable gases generate heat proportional to the concentration of target gas present. This heat increases the temperature of the wire coil, increasing its resistance. The increase in resistance is measured electrically and is the source of the signal. The higher the level of gas entering the sensor chamber, the higher the temperature of the measurement element, which means a higher reading on the display. For proper operation, a catalytic sensor needs oxygen. If the oxygen level drops below 8% vol, the gas will not go through the reaction process effectively and this will display readings that are lower than the actual amount on the monitor. Factors Affecting the Lifespan of Catalytic Sensors Typically designed to operate within specific temperature ranges. High temperatures can accelerate wear and reduce lifespan.
- Maintaining optimal humidity levels is crucial.
Excessive humidity can affect sensor components, leading to corrosion or malfunction.
- Paint fumes, cleaning products, sand, water, insects can reduce lifespan and compromise performance.
- Dust and dirt can compromise sensor performance lifespan, both during storage and operation.
When storing, package securely in a sealed container.
- Silicone, lotions, hair products, lubricants, gas additives, lead, sulfur compounds and chlorinated hydrocarbon vapours can poison catalytic sensors. Other compounds, especially hydrogen sulphide, halogenated hydrocarbons and anything containing astatine, bromine, fluorine, chlorine, and iodine can be absorbed or form compounds that are absorbed by sensor which can result in the temporary loss of sensitivity and in most cases a sensor will recover after a period of operation in clean air.
Even when the sensor is not powered, exposure to compounds that poison or inhibit the sensor can impact its lifespan.
- Excessive vibration or impact can damage the sensor. In addition to the factors listed above, most sensors will suffer general wear and tear and it may not always be easy to detect the damage caused, making regular maintenance important to help keep the sensors in good working order.
Regular maintenance includes inspecting, cleaning if necessary, bump testing and calibration.