What is combustible gas
Flammable gas mixes uniformly with air/oxygen within a certain concentration, forming a premixed gas that ignites or explodes on contact with a fire source. Due to its flammability and potential explosion, safety precautions are crucial, including the use of combustible gas detector.
How does a Combustible Gas Detector work
Its working principle is mainly based on the detection and response of the built-in sensor to the concentration of combustible gas. Depending on the technical principle, there are various types, but the basic principle is similar, which is to trigger an alarm by detecting the concentration of the mixture of combustible gas and air in the environment.
Several common working principles include:
Catalytic combustion sensor:
The catalytic combustion sensor, also known as the catalytic bead sensor, utilizes the principle of heat effect in catalytic combustion. When combustible gas enters the sensor, it undergoes flameless combustion under the catalysis of a catalyst, generating heat. This heat raises the temperature of the heating wire inside the sensor, changing its resistance value. By measuring this change in resistance value, the concentration of flammable gas can be estimated. When the concentration reaches a preset alarm threshold, the detector will sound an audible and visual alarm.
Electrochemical sensor:
Electrochemical sensors detect flammable gases via reactions at electrodes. Current generated is proportional to gas concentration. Measuring this current determines gas levels, triggering an alarm when reaching a threshold.
Semiconductor sensor:
The semiconductor sensor utilizes the characteristic that the conductivity of semiconductor materials changes with gas concentration to detect combustible gases. When flammable gas comes into contact with semiconductor materials, the conductivity of the materials changes. By measuring this change in conductivity, the concentration of combustible gas can be estimated. However, semiconductor sensors have relatively poor selectivity and stability, and are susceptible to interference from other gases.
Infrared absorption sensor:
The infrared absorption sensor detects gas by its absorption of IR light. Each gas has a unique absorption spectrum. The sensor uses an IR source and detector. Gas entering absorbs light at specific wavelengths, reducing detected intensity. Measuring this change determines gas concentration, triggering an alarm if needed.
How to select and purchase a Combustible Gas Detector
When purchasing, it is essential to determine the type of combustible gas to be monitored, as different types of combustible gases may require different types of detectors due to their varying chemical properties and combustion characteristics.
It is crucial to clarify the range of gas concentrations to be detected and the operating environment of the detector, including temperature, humidity, pressure, wind speed, etc., to ensure that the detector can function properly under these conditions.
Select the explosion-proof rating of the detector based on the category, class, and group of the combustible gas being detected, ensuring that the explosion-proof rating of the detector meets or exceeds the corresponding requirements of the gas in the area of use.
Choose a suitable detection principle based on actual needs, such as catalytic combustion, electrochemical, infrared optical, etc. Detectors with different principles have different advantages, disadvantages, and scopes of application.
Select the appropriate sampling method based on the site conditions, such as diffusion, single-point or multi-point aspiration, pneumatic aspiration, etc. For locations with concentrated sources of highly hazardous (Class I) toxic gas releases, single-point or multi-point aspiration detectors are preferred.
Consider the ambient temperature and humidity of the usage location and select detectors and controllers that can withstand these conditions. For example, electrochemical detectors may undergo physical changes in the electrolyte at high or low temperatures, affecting measurement accuracy.
Choose between wired or wireless communication methods based on actual needs, and consider whether a data processing system is required for data storage, recording, and abnormal alarm functions.
Characteristics of Combustible Gas Detector:
High Accuracy: Equipped with advanced sensing technology and signal processing algorithms, these detectors can achieve precise measurements of combustible gas concentrations. They can accurately sense and promptly alert for both low and high concentrations of combustible gases.
High Sensitivity: The detectors are capable of detecting minute changes in gas concentrations within a very short time, enabling them to respond promptly to potential safety threats.
Low False Alarm Rate: By optimizing sensor structures and algorithms, these detectors can accurately determine whether the detected gas is combustible, thereby reducing false alarms. Additionally, some detectors possess self-learning capabilities, enabling them to automatically adapt to environmental changes and further decrease false alarms.
Wide Detection Range: combustible gas detectors typically possess a wide detection range, capable of detecting various flammable gases such as methane, ethane, propane, etc.
Rapid Response: Upon detecting combustible gases, the detectors can swiftly emit audible and visual alarm signals, ensuring the timely discovery of gas leaks.
Intelligence: With the development of IoT technology, combustible gas detectors have become intelligent. By connecting to the internet or local area networks, users can view real-time data and operating status of the detectors from anywhere, enabling remote control and operation.
Stability: Stability factors are thoroughly considered during the design of combustible gas detectors, ensuring consistent performance over extended periods.
Application Scenarios of Combustible Gas Detector:
Petrochemical Industry: This industry involves the storage and transportation of large quantities of combustible and explosive substances, such as methane and ethylene. combustible gas detectors can monitor the concentration of these gases in real-time, preventing fires and explosions caused by gas leaks.
Pharmaceutical Industry: During pharmaceutical production, some chemical raw materials may be combustible or explosive, such as ethanol and acetone. Timely detection of gas leaks is crucial to avoid accidents.
Metallurgy: The smelting process in the metallurgy industry generates significant amounts of combustible and explosive gases, such as carbon monoxide and hydrogen. Real-time monitoring of gas leaks ensures production safety.
Construction: Construction sites often involve gas pipelines, gas appliances, and combustible materials like paint. Flammable gas detectors can monitor the concentration of combustible gases on-site, promptly alerting and enabling safety measures to prevent fires and explosions.
Tunnel Construction: Tunnel construction involves underground operations, where the accumulation of combustible gases is a risk. Combustible gas detectors monitor the concentration of these gases within tunnels, issuing timely alarms to ensure worker safety and facilitate cleaning and ventilation measures.
Fire and Rescue: Combustible gas detectors play a vital role in fire and rescue operations. They help firefighters grasp the concentration of flammable gases at fire or explosion sites, providing accurate information for rescue operations and ensuring their safety and efficiency.
Mine Rescue: In mine accidents, combustible gases are a primary cause of explosions and suffocation. Combustible gas detectors monitor their concentrations in mines, detecting dangers in advance and assisting rescuers in adopting effective measures to protect trapped miners’ lives.
Routine Maintenance of Combustible Gas Detector:
Regular Calibration: It is recommended to calibrate the detector once every six months to ensure the accuracy of measurement data.
Keep Clean: Regularly clean the detector’s exterior and sensor window to prevent dust and impurities from affecting detection. Avoid contacting cleaning fluids with electrical parts and refrain from using wet cloths for wiping.
Inspect Cables and Wiring: Regularly check the signal cables and wiring for integrity, avoiding faults caused by cable aging, outer skin damage, or loose connections.
Attend to Environmental Factors: Avoid installing detectors in damp, dusty, or corrosive gas environments. If necessary, implement appropriate protective measures.
Proper Grounding: Ensure the detector is grounded properly to shield against electromagnetic and lightning interference.
Timely Repair or Replacement: Once a detector malfunctions or performance declines, promptly contact professionals for repair or replacement. Never attempt to disassemble or repair the detector yourself, as this may cause further damage or safety hazards.
You may also be interested in:
Industrial Flammable Gas Detectors
