Coal mine GJC4 high and low concentrations of methane sensor methane alarm detector, gas sensor 
 Developed to meet the needs of our coal mine monitoring of underground methane, it can be continuous automatic underground methane concentrations converted into standard electrical signal transmission to the associated equipment, and has a place to display the methane concentration, overrun audible and visual alarm and power failure -line inspection by the state explosion-proof inspection agency, and various types of monitoring systems and power-off instrument, wind power and gas locking device matching, appropriate in the face of coal mining, electrical and mechanical chamber, and back to the wind tunnel locations for stationary use . 
 The main technical indicators 
 Measuring range: 0 to 4.00% of CH4 
 Basic measurement error: 
 0.00 ~ 1.00% CH4 ± 0.10% of CH4 
 1.00 ~ 2.00% CH4 ± 0.20% of CH4 
 2.00 ~ 4.00% CH4 ± 0.30% of CH4 
 Display: four red LED display 
 Features: 1 - zero; - adjust sensitivity; - adjust alarm points; - tune power-off point; 5 - The self-test 
 After three: the measured values ??(% CH4) 
 Signal output: 
 Signal with a load capacity: 0 ~ 400Ω 
 Alarm method: two intermittent sound and light alarm 
 Sound intensity> 85dB, light intensity: visibility> 20m 
 Alarm point range: 0 to 4% of CH4 is continuously adjustable 
 Power point set: can be given for 0.50,0.75,1.00,1.25,1.5,2.0% CH4, the corresponding complex power point power point lower limit can be set in the range of 0-3% CH4. 
 Sampling methods: diffusion type; component detection speed of response: <30S 
 Thermal catalytic component life: One year 
 Intrinsically safe parameters: a) μi: 18V (DC) Ii: 70mA 
 b) Ci: 0.08μF li: 0mA 
 Operating voltage: DC9-24V; Operating Current: ≤ 85mA 
 Explosion-proof type: mining, intrinsically safe and flameproof; proof mark: ExibdI 
 Dimensions: 190 × 114 × 57 Weight: 700g 
 The coal the GJC4 high and low concentrations methane sensor, GTH500 carbon monoxide sensor