Overview
SK-7500-LEL-BJY LEL on-line monitoring system is an on-line monitoring system for continuous monitoring of LEL (lower explosive limit) content of organic matter in pipelines. The system integrates gas sampling, pretreatment, concentration detection, data display and communication functions. It has a simple structure, wide dynamic range and strong real-time performance. It can realize on-site unattended and can communicate with the enterprise DCS system.
Features
1. The pre-treatment design is adopted, the overall volume is small, the installation is convenient, and it can effectively deal with the harsh environment such as moisture, tar, dust, etc.
2. Using the original high-performance Sensor, strong anti-interference ability, accurate and stable monitoring data, long service life.
3. Equipped with infrared remote control, full-function operation can be realized without opening the lid, and maintenance is convenient.
4. Standard 4-20mA, RS485 and relay output signals, easy to access PLC, DCS and other industrial control systems or as a stand-alone control.
5. Optional wireless modules such as DTU and LORA can be used to upload data to enterprise DCS or third-party platforms in real time.
6. Optional 7-inch industrial touch screen, intuitive and clear display of real-time concentration and Linear dispersion map.
Principle
The system is based on active sampling and professional sample gas pretreatment. Pipeline gas is extracted by a sampling pump, and after pretreatment such as precision filtrating, cooling and dehumidification, and flow control, a clean, drying, and constant sample gas is obtained. The sample gas is then sent to a detector using the infrared NDIR principle. The NDIR Sensor uses the absorption characteristics of different gas molecules to specific wavelengths of infrared light. According to Lambert-Beer's law, the gas components are identified and their LEL concentrations are determined by measurement of Absorption intensity.
Applications
Generally used for RTO front-end pipeline monitoring to prevent places with high concentration and explosion hazard
Standards
GB3836.1-2010、GB3836.2-2010、GB 3836.15-2000、GBT50493-2019、GB12358-2006、GBZ 2.1-2007、GB 4208-2008、GB 16297－1996、GB/T 16157-1996、GB/T 5468-1991、HJ/T 397-2007、HJ/T 76-2017、HG/T 20507-2014
Steps
1. System installation: According to the requirements of the sampling station selection point (such as priority selection of vertical pipe section, avoid the sharp change of elbow and section, meet the requirements of upstream and downstream distance), use welded flange or threaded adapter for installation.
2. Utility connection: Connect to the AC220V power supply, and connect the signal cable according to the cable specifications (such as three-core Shielding cable for 4-20mA, four-core Shielding cable for RS485). If the Back flushing function is optional, a clean instrument air source needs to be connected.
3. System start-up: After power on, the system will automatically start the sampling pump, start extracting sample gas and perform pretreatment.
4. concentration monitoring and display: pretreated sample gas into the detector, real-time measurement of LEL concentration and displayed on the LCD screen or optional Touchscreen.
5. data output and linkage: monitoring data through 4-20mA, RS485 and other signal output to the control system, and can be linked relay control peripheral equipment.
6. Maintenance operation: Alarm point setting, zero point adjustment, target point calibration and other operations can be carried out through the infrared remote control or built-in buttons. The system supports automatic zero adjustment and calibration functions.
Notice
* Selection of the sampling station is crucial, ensure the representativeness of the sample, and strictly follow the upstream and downstream distance requirements from elbows, valves and other components.
The system power supply is AC220V, and the signal cable needs to use a Shielding cable with the specified diameter. During long-distance transmission, the wire diameter should be thickened and the Shielding layer should be grounded.
* If the Back flushing function is selected, the air source must be clean, oil-free and water-free instrument wind, and the pressure and flow must be stable within the required range.
* Equipment Ambient Temperature should be between 0~ 50 ℃, humidity ≤ 95% RH (no condensation). Applicable pipeline working conditions are temperature ≤ 80 ℃, micro negative pressure, normal pressure or positive pressure, and dust and water vapor content is very small.
* The equipment has requirements for vibration, and it is necessary to ensure that the vibration of the installation environment is ≤ 100 Hz (0.3m/s).
The explosion-proof level of the system is ExdIIBT4/6Gb, and it needs to be installed and used in dangerous places that meet the explosion-proof requirements.
* Sensor and equipment life is affected by the Operating Environment and principle, please pay attention to regular maintenance and calibrating.
* When performing zero adjustment, calibration and other operations, please strictly follow the instructions or use the remote control to avoid misoperation.
