There are several types of methane sensor used in methane leak detection. These include Laser diode, Infrared image sensor, and semiconductor sensors. Each of these has its own unique advantages and disadvantages. Let’s look at four of them to get a better idea of what they do and how they work.
Catalytic bead
Catalytic bead sensors are the most common type of methane leak detector, and they are used to detect methane leaks in underground storage tanks. Catalytic bead sensors work by igniting the gas. However, they must be calibrated on a regular basis. Oldham recommends doing so at least once every quarter.
These sensors use two fine platinum wire coils embedded in an alumina bead and are connected by a Wheatstone bridge circuit. One of impregnated with a special catalyst, while the other is treated to prevent oxidation. When the combustible gas passes, current flows through the coils and raises the temperature. This increases the resistance of the platinum coil within the bead and creates an imbalance in the Wheatstone bridge.
Infrared sensors are a more environmentally friendly alternative to catalytic bead sensors. They do not require oxygen and are able to detect a wide range of combustible gases, including methane. Unlike catalytic bead sensors, infrared sensors use a comparison beam of two beams to determine the methane concentration.
Infrared image sensor
The infrared image sensor for methane and petroleum chemical leak detection is a camera system that analyzes images and detects gas leakages. The camera is equipped with an infrared detector that concentrates infrared energy emitted from the target object. The sensor transmits this information to an electronic device, which transforms the information into images. These images are then displayed on a standard LCD screen.
The proposed system has a high detection rate and can detect invisible gases. The camera is based on image processing techniques and is relatively simple to use. The image data is streamed directly from the sensor and is converted to a 256-level image. The resulting image is then processed to achieve the 16,384-pixel resolution of the sensor. The proposed algorithm employs an adaptive average method to remove background in real-time. The system also exhibits improved performance and memory requirements.
The Gas330 gas leak sensor uses a C330M-G middle-wave COOLED infrared detector, which has a NETD of 15mk and a frame rate of 30Hz. Its spectral response band is 3.2-3.5 mm and is able to detect a wide range of gases.
Laser diode
A laser diode is an effective detector for methane leak detection. These devices can detect methane leaks from a great distance. The lasers used in methane leak detection are tunable. This feature increases sensitivity and selectivity. The lasers used in these devices can be tuned to detect the presence of methane at low concentrations.
The laser gas detectors have a unique advantage over solid state sensors. These devices have very low cross-sensitivity to other gases, such as oxygen and humidity. This reduces the cost and power consumption of single point measurements. They are also less susceptible to degradation and poisoning.
The RLGD-100 is a portable methane leak detection device using TDL technology. It has a 0.1-second response time, and can locate methane up to 30 meters away. It is extremely easy to operate, maintenance-free, and has a long battery life. It also features an LCD display and wireless data logging.
Semiconductor sensor
Semiconductor sensors are used to detect methane leaks. These sensors detect the gas by detecting changes in the electrical resistance of chemisorbed oxygen. The amount of chemisorbed oxygen depends on the concentration of methane in the air.
A semiconductor gas sensor can detect methane in the air at concentrations ranging from 300 to 10,000 ppm. The sensor can be interfaced with a microcontroller via one analog input pin. The sensor’s sensitivity and low power consumption make it a promising candidate for methane leak detection.
Several approaches have been developed to improve semiconductor gas sensors. One way is to dope the semiconductor layer with a catalytic element such as palladium. developed a methane sensor that used platinum-doped tin oxide. The synthesis of doped 2 involved a hydrothermal process and a thermal reduction process. In addition, the reduced the surface adsorption energy.
Conclusion
The sensor works by measuring the temperature of the gas-sensitive layers. The response is measured as a ratio R 0/R CH4 in air and in a mixture of air and methane. The test gas is prepared in gas balloons under pressure and certified by the Ukrainian Center of Certification and Metrology (UCCM). Several dilution generators were also used to determine the dependence of the sensor’s response on CH4 concentration.
