Combustible and toxic gas monitoring
SimtoLink gas sensors cover combustible gases (CH4 methane, C3H8 propane, and others) and toxic gases (CO, H2S, NH3, O2). Pick electrochemical, semiconductor, or catalytic combustion for the site. Electrochemical is the usual choice for CO, H2S, and O2. Semiconductor covers some combustible and reducing gases, including NH3, and cost-sensitive jobs. Catalytic combustion is the classic method for combustible gas. Response is under 30 s, for chemical plants, coal mines, and tunnels.
The sensors carry a national explosion-proof certificate for hazardous areas, as intrinsically safe or flameproof. The head is modular, so it can be changed on site without sending the whole unit back, which cuts maintenance cost. They are already on hundreds of coal-mine, chemical, municipal, and tunnel jobs, more than 50,000 sensors in all.
Gases and Specifications
SimtoLink gas sensors come in several builds by gas and sensing principle, for different safety jobs. The table is a typical reference:
| Gas | Sensing principle | Typical use |
|---|---|---|
| Combustible CH4/C3H8 | Catalytic combustion / semiconductor (by site) | Coal mines, gas, tunnels |
| CO / H2S | Electrochemical (usual choice) | Chemical plants, utility tunnels, confined spaces |
| NH3 and other reducing gases | Electrochemical / semiconductor (optional) | Cold stores, chemical plants, livestock, workshops |
| O2 deficiency | Electrochemical | Utility tunnels, traffic tunnels, underground workings |
| Combined | Multi-channel | Several gases at once |
Range and accuracy depend on the gas. Output is 4–20 mA or Modbus. Supply is DC 12–24 V. Warm-up is under 5 min. Typical life is 2–5 years for electrochemical, 3–5 years for catalytic combustion, and about 3–10 years for semiconductor, all depending on the gas and the duty. Ingress is IP65. Zero and span calibration is recommended every 6–12 months. These are typical figures for the standard models. Special gases or sites can take a custom build.
Typical Deployments
From methane underground to toxic gas in a chemical plant and a city utility tunnel, the sensors cover safety monitoring across industries. Typical jobs and what changed:
Underground methane
One mine put more than 200 methane sensors underground. An industrial ring takes the readings to the safety platform in real time, and an over-limit trip cuts power and starts evacuation, in line with the coal-mine safety rules.
Chemical tank farms
One plant put CO and H2S sensors on the tank farm and in the pipe racks. A SimtoLink gateway raises an early leak alarm so people can get clear.
City utility tunnels
One city utility tunnel uses multi-gas sensors for CH4, O2, and H2S, so inspection crews stay safe and the readings reach the tunnel platform.
Tunnels and confined spaces
CO and O2 sensors in tunnels and underground garages watch ventilation and oxygen deficiency.
Selection and Maintenance
- Explosion-proof certificate: Hazardous areas need a certified sensor, intrinsically safe or flameproof.
- Sensor life: Electrochemical about 2–5 years; catalytic combustion about 3–5 years; semiconductor usually 3–10 years, by model and duty. Plan the change-out.
- Site conditions: High humidity or dust calls for a filter cap. Several gases can share a combined head or a multi-channel unit. Semiconductor heads need a check on temperature, humidity, and cross-sensitivity, with compensation or a confirmed selection for the duty.
- Calibration interval: Electrochemical, zero and span every 6 months. Catalytic combustion, zero in clean air. Semiconductor, zero and sensitivity on the maker's interval, shorter if interfering gases are common.
- Records: At order time, name the gases, the range, the principle (electrochemical, semiconductor, or catalytic combustion), and the site. Keep a sensor log of location, calibration date, and change-out interval.
How a Job Is Run
A gas-monitoring job usually runs like this:
Replace a head when its life is up, so a dead sensor does not miss an alarm. In heavy dust, clean the filter cap so it does not slow the response. SimtoLink replaces and calibrates sensors, including an annual maintenance contract and a site visit.
Support
SimtoLink helps select, calibrate, and replace gas sensors, including explosion-proof units and special gases, and can put that on an annual maintenance contract. Ask for the product manual and a quote.