As a supplier of hydrogen sensors, I often encounter inquiries from customers regarding the suitability of our sensors for use in explosive environments. Electrochemical hydrogen sensors are a popular choice for detecting hydrogen due to their high sensitivity, selectivity, and relatively low cost. However, the question of whether they can be safely used in explosive environments is a critical one that requires careful consideration.
Understanding Explosive Environments
Before delving into the suitability of electrochemical hydrogen sensors for explosive environments, it is essential to understand what constitutes an explosive environment. An explosive environment is a location where there is a risk of an explosion due to the presence of flammable gases, vapors, or dusts. These environments are typically classified into zones based on the likelihood and duration of the presence of explosive atmospheres.
Zone Classification
- Zone 0: An area in which an explosive gas-air mixture is present continuously or for long periods.
- Zone 1: An area in which an explosive gas-air mixture is likely to occur in normal operation.
- Zone 2: An area in which an explosive gas-air mixture is not likely to occur in normal operation and, if it does occur, will exist only for a short time.
Explosion Protection Concepts
To ensure safety in explosive environments, various explosion protection concepts are employed. These concepts aim to prevent the ignition of explosive atmospheres by controlling the sources of ignition. Some common explosion protection concepts include:
- Intrinsic Safety (Ex i): This concept involves limiting the energy available in electrical circuits to a level that is insufficient to ignite an explosive atmosphere.
- Flameproof Enclosure (Ex d): A flameproof enclosure is designed to contain an explosion that occurs inside the enclosure and prevent it from spreading to the surrounding atmosphere.
- Pressurization (Ex p): Pressurization involves maintaining a higher pressure inside the equipment than the surrounding atmosphere to prevent the ingress of explosive gases.
Electrochemical Hydrogen Sensors: How They Work
Electrochemical hydrogen sensors operate based on the principle of electrochemical oxidation or reduction of hydrogen at an electrode surface. The sensor typically consists of a working electrode, a counter electrode, and a reference electrode immersed in an electrolyte. When hydrogen comes into contact with the working electrode, it undergoes an electrochemical reaction, generating an electrical current that is proportional to the concentration of hydrogen in the gas sample.
Advantages of Electrochemical Hydrogen Sensors
- High Sensitivity: Electrochemical sensors can detect hydrogen at very low concentrations, making them suitable for applications where early detection is crucial.
- Selectivity: These sensors are highly selective to hydrogen, minimizing the interference from other gases.
- Low Power Consumption: Electrochemical sensors consume relatively low power, making them suitable for battery-powered applications.
- Fast Response Time: They can provide a rapid response to changes in hydrogen concentration, allowing for real-time monitoring.
Limitations of Electrochemical Hydrogen Sensors
- Limited Lifetime: The lifespan of electrochemical sensors is typically limited to a few years, depending on the operating conditions.
- Sensitivity to Temperature and Humidity: The performance of electrochemical sensors can be affected by changes in temperature and humidity, requiring compensation for accurate measurements.
- Risk of Poisoning: Certain gases and contaminants can poison the electrodes of electrochemical sensors, reducing their sensitivity and accuracy.
Using Electrochemical Hydrogen Sensors in Explosive Environments
The use of electrochemical hydrogen sensors in explosive environments requires careful consideration of the explosion protection requirements and the potential risks associated with the sensor operation. While electrochemical sensors themselves do not generate sparks or high temperatures, there are still potential sources of ignition that need to be addressed.
Intrinsic Safety
One of the most common methods of ensuring the safety of electrochemical hydrogen sensors in explosive environments is to design them to be intrinsically safe. Intrinsic safety involves limiting the electrical energy in the sensor circuit to a level that is insufficient to ignite an explosive atmosphere. This can be achieved through the use of appropriate electrical components, such as resistors, capacitors, and diodes, to limit the current and voltage in the circuit.
Certification
To demonstrate compliance with the explosion protection requirements, electrochemical hydrogen sensors used in explosive environments must be certified by a recognized testing laboratory. Certification ensures that the sensor has been tested and meets the relevant standards for use in explosive atmospheres. Some common certification standards include ATEX, IECEx, and UL.
Installation and Maintenance
Proper installation and maintenance of electrochemical hydrogen sensors are essential to ensure their safe and reliable operation in explosive environments. The sensors should be installed in accordance with the manufacturer's instructions and the relevant safety standards. Regular maintenance, including calibration and inspection, is also necessary to ensure the continued accuracy and performance of the sensors.
Our Hydrogen Sensor Products for Explosive Environments
At our company, we offer a range of hydrogen sensors that are suitable for use in explosive environments. Our sensors are designed to meet the highest standards of safety and performance, and they are certified for use in explosive atmospheres.
Catalytic Combustion Hydrogen Sensor SRE1012
The Catalytic Combustion Hydrogen Sensor SRE1012 is a reliable and cost-effective solution for detecting hydrogen in explosive environments. This sensor operates based on the principle of catalytic combustion, where hydrogen reacts with oxygen on the surface of a catalyst, generating heat that is detected by a thermistor. The sensor is designed to be intrinsically safe and is certified for use in Zone 1 and Zone 2 explosive atmospheres.
MEMS Hydrogen Gas Sensor SMD1012
The MEMS Hydrogen Gas Sensor SMD1012 is a high-performance hydrogen sensor that utilizes microelectromechanical systems (MEMS) technology. This sensor offers high sensitivity, fast response time, and low power consumption, making it suitable for a wide range of applications, including those in explosive environments. The sensor is designed to be intrinsically safe and is certified for use in Zone 2 explosive atmospheres.
Conclusion
In conclusion, electrochemical hydrogen sensors can be used in explosive environments, provided that they are designed and certified to meet the relevant explosion protection requirements. Intrinsic safety is a key consideration when using these sensors in explosive atmospheres, and proper installation and maintenance are essential to ensure their safe and reliable operation. At our company, we offer a range of hydrogen sensors that are suitable for use in explosive environments, including the Catalytic Combustion Hydrogen Sensor SRE1012 and the MEMS Hydrogen Gas Sensor SMD1012. If you are interested in learning more about our products or have any questions regarding the use of hydrogen sensors in explosive environments, please do not hesitate to contact us for further discussion and potential procurement.
References
- IEC 60079-11: Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i".
- ATEX Directive 2014/34/EU: Equipment and protective systems intended for use in potentially explosive atmospheres.
- UL 913: Standard for Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations.