Selecting the appropriate fixed gas detector is essential for maintaining safety in industrial environments such as petrochemical plants, refineries, and manufacturing facilities. Fixed gas detectors provide continuous monitoring of hazardous gases, enabling early detection and response to prevent accidents. At Shanghai Gewei Electronic Safety Equipment Co., Ltd., we specialize in developing reliable gas detection systems, including our GDE, GDC, and GDA series, which incorporate advanced sensor technologies for precise performance.
1. Detection Principle
The detection principle forms the foundation of any fixed gas detector. Common types include catalytic combustion, infrared, semiconductor, electrochemical, and photoionization (PID). Each principle suits specific gases and conditions. For combustible gases like methane, catalytic combustion sensors in our GDC series detect oxidation reactions effectively. Infrared sensors, used in the GDE series, measure gas absorption of infrared light, offering long lifespan over 5 years and resistance to poisoning. Electrochemical sensors work well for toxic gases such as CO and H2S, while PID suits volatile organic compounds (VOCs).
Choose based on the target gas and environment. In oxygen-deficient areas, infrared principles avoid false alarms from catalytic types. Our products support modular sensor integration, allowing flexibility for different principles without replacing the entire unit.
2. Target Gases and Application Needs
Identify the gases present in your facility. Industrial sites often monitor combustible gases (LEL), oxygen levels, and toxics like ammonia or chlorine. Our fixed gas detectors cover a range including methane, propane, hydrogen sulfide, and carbon monoxide. For multi-gas detection, consider systems like the GDA series, which can be configured for specific combinations.
Multi-Gas vs. Single-Gas Detectors
Single-gas units suffice for focused monitoring, but multi-gas detectors provide comprehensive coverage. Our GM810 and GM820 controllers integrate multiple sensors, supporting up to 256 points for large-scale installations.
3. Environmental Compatibility
Industrial settings vary in temperature, humidity, and corrosiveness. Detectors must withstand -40°C to 70°C and up to 95% RH. Explosion-proof designs are critical for hazardous areas. Our GDE and GDC series feature Exd IIC T6 Gb certification, suitable for Zone 1 and 2. Materials like epoxy-coated aluminum or stainless steel housing protect against corrosion in chemical plants.
For dusty environments, IP66-rated enclosures prevent ingress. We incorporate zero-point temperature compensation to maintain accuracy across fluctuations.
4. Accuracy and Sensitivity
Precision is non-negotiable for reliable alerts. Look for ±3% accuracy in infrared sensors and ±5% in catalytic types. Sensitivity ensures detection at low PPM or %LEL levels. Our GDE series achieves ±3% with infrared, while GDC offers ±2% repeatability. Drift control, under 2% per half-year, minimizes recalibration needs.
Calibration and Maintenance
Smart sensors in our lineup allow pre-calibrated plug-and-play replacement, reducing downtime. Automatic zero calibration further enhances long-term stability.
5. Response Time and Sensor Lifespan
Fast response prevents escalation. T90 times of 20-25 seconds are standard in our detectors. Sensor lifespan varies: infrared over 5 years, catalytic 1-3 years. The GDE’s laser sensors extend reliability in harsh conditions. Preheating under 3 minutes ensures quick startup.
6. Signal Output and System Integration
Integration with control systems is key. Outputs include 4-20mA analog, RS485 Modbus, and relay contacts. Our detectors support distances up to 1.5km via bus or analog. For modern setups, IoT compatibility via 4G/WiFi modules and cloud platforms enables remote monitoring. The GM8 series controllers use DCS architecture for scalable networking with external devices.
Programmable outputs define fault states (e.g., 0-2mA for power failure), ensuring clear diagnostics.
7. Installation and Maintenance Features
Ease of deployment reduces costs. Bus-type addressing in our GDC series simplifies wiring. Tool-free, coverless operation via remote control or LED modules allows adjustments without exposure. Mounting options include wall or pipe, with 3/4″ NPT interfaces for accessories like sound-light alarms.
Power and Connectivity
DC24V operation with 18-30V range suits stable power supplies. Modular design facilitates expansion and fault isolation.
8. Compliance, Certification, and Cost-Effectiveness
Ensure adherence to standards like GB15322 and IECEx. Our products hold CCC, CPA, and explosion-proof certifications. Cost-effectiveness balances initial investment with longevity; infrared options lower maintenance expenses over time. Evaluate total ownership cost, including integration with our IoT cloud for data analytics.
At Shanghai Gewei, we tailor solutions like the GDA series for cost-sensitive applications in pharmaceuticals and breweries, offering high integration at competitive pricing.
By considering these eight factors, facilities can select fixed gas detectors that enhance safety and efficiency. Our gas detection systems, including advanced infrared sensors, integrate seamlessly into industrial workflows, providing robust protection against gas hazards.