What Is a Combustible Gas Detector?
Combustible gas detectors are detectors that respond to single or multiple combustible gas concentrations. There are two types of combustible gas detectors: catalytic and infrared optical. The catalytic type combustible gas detector uses the resistance change of the refractory metal platinum wire to measure the combustible gas concentration. When the flammable gas enters the detector, it causes an oxidation reaction (flameless combustion) on the surface of the platinum wire. The heat generated by it raises the temperature of the platinum wire, and the resistivity of the platinum wire changes. The infrared optical type uses an infrared sensor to detect the alkane-based combustible gas in the field environment through the absorption principle of an infrared light source.
- Combustible gas detectors are detectors that respond to single or multiple combustible gas concentrations. There are two types of combustible gas detectors: catalytic and infrared optical. The catalytic type combustible gas detector uses the resistance change of the refractory metal platinum wire to measure the combustible gas concentration. When a flammable gas enters the detector, it causes an oxidation reaction (flameless combustion) on the surface of the platinum wire. The heat generated by it raises the temperature of the platinum wire, and the resistivity of the platinum wire changes. The infrared optical type uses an infrared sensor to detect the alkane-based combustible gas in the field environment through the absorption principle of an infrared light source.
Combustible gas detector product introduction
- The combustible gas detector is an industrial high-performance wide-band gas leak detector. It has 6 gas leakage visual inspection lamps, and the display lights turn on sequentially as the gas leakage increases. Can be used to detect hydrocarbons (methane, ethane, propane, benzene, acetylene, butane, n-butane, isobutane, pentane, hexane, gasoline, toluene, etc.), halogenated hydrocarbons (chloromethane, methylene Chlorine, trichloroethane, vinyl chloride), alcohols (methanol, ethanol, propanol), ethers (methyl ether), ketones (butanone, acetone), methyl acetate and other compounds (hydrogen, sulfur dioxide, ammonia, sulfurization Hydrogen, industrial solvents, dry cleaning fluids, etc.). According to the detection principle, there are usually four types: thermal conductivity type, semiconductor type, catalytic combustion type (contact combustion) and infrared absorption type [1] .
- A flammable gas detector is a point-type gas detection device installed in an explosive hazardous environment. It converts the on-site flammable gas concentration into an electrical signal and transmits it to a monitoring device located in a safe area to achieve the purpose of monitoring the on-site flammable gas concentration. During the design and construction process, combustible gas detectors should follow the corresponding standards and requirements. [2]
Combustible gas detector features
- 1. Wide range of flammable gas detection, the instrument has extremely high sensitivity to the small amount of mist and gas flammable compounds, and can check the leakage source to ensure the safety of the potentially dangerous place.
- 2. Automatic warm-up
- 3. Visual Leakage Visual Inspection Light
- 4. Cordless operation
- 5. Rechargeable battery powered
- 6. Includes suitcase, charger, etc.
- 7. Adjustable sensitivity
- 8.Long and flexible probe
Flammable gas detector range and sensitivity
- Detectable substance
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Combustion gas detector wiring instructions
- The controller uses a three-core shielded wire to connect to the detector (Note: the single-core wire diameter is not less than 0.75mm national standard wire), the shield layer is connected to the controller case and is reliably grounded. When using an RVV cable, wear a metal pipe and connect the metal pipe to the chassis reliably. Refer to the controller and detector wiring diagrams and connect the controller and the corresponding terminals of the detector.
- Combustion gas detector construction wiring instructions
Combustible gas detector
- A sturdy and easy-to-use intelligent combustible gas detector designed to detect the change in the concentration of flammable alkanes from 0 to 100% of the lower explosive limit. The detector uses a patented "small plug-in replaceable" infrared optical sensor. The infrared sensor is characterized by long-term work stability and minimal periodic maintenance. Infrared gas sensors are an excellent alternative to traditional catalytic combustion sensors in certain measurement environments.
- The infrared flammable gas detector is ideal for the following applications:
- Frequent catalytic poison gas exposure
- Frequent high flammable gas emissions
- Anoxic environment
- Detect environments that are not easy to achieve
- typical application
- Offshore operation platform and drilling platform Refinery
- Petrochemical plant CNG and LPG treatment
- Wastewater treatment Chemical plant
- Pumping station Thermal power plant
- Features
- Unique small plug-in field replaceable sensor
- No interference, intelligent detector interface
- Output: 4-20mA, RS-485 data bus and 3 alarm relays
- Minimal maintenance requirements
- Heated optical design avoids condensation
- Fault self-diagnosis function
- Low cost for long-term use
- Five-year rated cost quality guarantee
- Low energy consumption
- The combustible gas detector is calibrated and debugged with software using methane as a standard gas. The company can also sample other gases, but the customer must declare in advance when ordering. The following calibration gases are available from the company:
- Methane, ethane, propane, butane, pentane, hexane, heptane, octane, ethylene, propylene, butene, pentene, hexene, octene, cyclopropane, cyclohexane, cyclohexene, hydrazone Olefin, benzene, toluene, xylene, methanol, ethanol, propanol, isobutanol, dimethylamine, trimethylamine, pyridine, dimethyl ether, ether, vinyl ether, ethylene oxide, tetrahydrofuran, dioxane , Butanone, pentanone, heptone, methyl isobutyl ketone
Technical characteristics of combustible gas detectors
Combustible gas detector introduction
- Technology Infrared flammable gas detectors are non-interference intelligent products with good safety performance and flexible and simple operation. A major feature of this detector is its automatic calibration function, which can guide the operator step by step through the prompts on the backlit LCD display. The infrared gas detector provides three different output methods: analog signal 4 ~ 20mA DC; RS-485 communication interface and 3 relays (two alarms, one fault self-test). The bell can be debugged and programmed on site. These different output methods provide maximum flexibility for system setup. The 500 series only provides 4 ~ 20MA DC output. The control circuit is based on a micro-processing chip, packaged as a plug-in module and connected to a standard connection template. The sensor and signal generator are installed in an explosion-proof enclosure with a glass cover. The backlit digital display shows both sensor readings and menu functions during programming. All infrared gas detectors belong to the electrical category: Class I; Groups B, C, D; Division 1. This product line continues the philosophy of "easy installation and easy maintenance" embodied in the design of gas sensors.
Flammable gas detector without interference packaging
- The detector is enclosed in an explosion-proof metal housing. A cover with a glass is rotated on the housing. The magnetic programming button on the transmitter panel can be operated by the handheld magnetic programming tool, which ensures the sensor interface operation No interference. All calibrations and on-site debugging can be performed without opening the cover and maintaining the original state of the site.
Easy calibration of combustible gas detectors
- A calibration prompt is displayed on the backlit LCD display, which greatly simplifies the calibration process. The technician can simply start the calibration process with a magnetic programming tool. Once the calibration procedure is started, the detector displays the calibration menu. The menu provides two options: zero calibration and initial calibration. Select ZERO to start the auto-zero function. The calibration end display will return to the calibration menu. Selecting SPAN will start the automatic start state calibration, and the display will ask for the gas set by the detector and its concentration. As soon as the gas is supplied, the detector automatically starts calibration. When the signal stabilizes, the detector records the initial data and prompts the operator to disconnect the gas source. Once the gas concentration returns to zero, the detector will automatically resume its normal operation. If the detector cannot perform the calibration procedure for any reason, the detector will display an error message. This process takes less than three minutes and is almost error-free.
Combustible gas detector signal output
- The infrared gas sensor has two kinds of signal output: analog 4 ~ 20mA output and RS-485 data bus output. There is only one 4-20 mA output. The output signal is a 4 ~ 20mA linear analog signal related to the detection range. This signal is compatible with Detcon's 10-series and 12-series multi-module controllers, programmable logic controllers, and other standard data acquisition equipment. The analog output has two other functions. First, when entering the calibration menu, the 4-20mA signal will drop to 2mA. This low current is maintained until the sensor returns to normal operation. Second, once an error occurs, the 4-20mA signal will drop to 0mA, and this condition will remain until the error state returns to normal. Changes in these output signals can be used by external devices to identify and record the operating status of the sensor.
- RS-485 data communication uses Modbus RTU protocol, this protocol is compatible with almost all programmable logic controllers, human-machine interface software and other control systems. Because Modbus RTU protocol is a standard. The following information is available from the RS-485 communication interface: detector readings, detector alarm points, calibration mode, detector errors, two alarm statuses, and calibration procedure errors. The RS-485 address can be changed by a DIP switch. The communication is two-wire, half-duplex, with a 600-type detector as its servo device. In theory, the main controller can control 256 different 600 detectors at the same time from 4,000 feet away.
Combustible gas detector alarm features
- The infrared gas detector has three relays, two for alarm and one for fault self-test. Without relays. All three alarms can be adjusted to the following working states through jumpers: contact status (can choose to be normally open or normally closed), and the relay can be adjusted to be continuously energized or continuously de-energized. In addition, the alarm can be adjusted to mute. The alarm point can be adjusted through the menu. The self-test alarm can also be adjusted to mute state through the menu and respond to the following situations: zero drift is less than -10% of the measurement range, the microprocessor is wrong, the infrared light source is wrong, the signal parameters are wrong, or any other situation. The relay contact setting current is 5 amps at 250 volts AC; 5 amps at 30 volts DC.
Flammable gas detector programming status
- The programming status function enables the user to set the sensor's alarm point, RS ~ 485 identification number, detection gas, and measurement range using the magnetic programming tool in the "VIEW PROGRAMMING STATUS" on the menu. Once in the program, the display will automatically page through to complete all commissioning steps. When finished, the sensor will return to normal operation.
Flammable gas detector over range
- When the gas concentration measured by the detector exceeds 100% LEL of the measurement range, the display will flash and show the highest value. When the gas concentration returns to the measurement range, the display will return to the normal working state.
- Catalytic Combustion Gas Detector
- It is used to monitor the change of flammable gas in the surrounding air from 0 to 100% LEL. The sensor uses catalytic combustion technology, which can be replaced on site. Catalytic combustion sensors are sensitive to a wide range of flammable gases. This technology has universal applicability for flammable gases. The sensor is specially designed with anti-poisoning function and can work reliably in most industrial environments for five to ten years.
- The strongest structure
- Electrolytic polishing of 316SS stainless steel structure
- 100% epoxy encapsulated circuit
- I / O input and output multi-layer protection (overvoltage, wiring error, anti-electromagnetic interference / anti-radio wave interference)
- Waterproof, anti-corrosion, anti-vibration
- Modular design and easy maintenance
- Modular design
- Plug and play components
- Minimal components (universal design concept)
- Quick thread removal (easy sensor replacement)
- Integrated calibration interface
- Technical index:
- Detection principle
- Catalytic Combustion Technology