This example describes the gas limit alarm miner’s lamp for coal mine a gas explosion in gas environment, the miners carry the device, can lighting, but also of methane gas were detected.
when the wells occurs Methane gas overrun , the in time will flash alarm signal to remind miners in time evacuated .
The gas gauge alarm miner’s lamp circuit by the sense amplifier and alarm circuit, in Figure as shown .
Detected amplifier by the sensor , resistors Rl-Rl5, potentiometer RP, transistors Vl-V7 and voltage regulator diode VS composition. Alarm circuit consists of resistors R16-Rl8, capacitors Cl-C4, transistors V8 and V9, Diodes VDl and VD2, relay K and miner EL composition. Turn the power switch S (Sl, S2) , after , EL light , the entire circuit to the power supply .
The sensor The end of detects methane gas , the sensor white of pure carrier elements B and black vector catalytic element A of the resistance remained stable , V6 , and V7 is off , the V8, V9 , and Cl-C4, R16-R18, K , VDl composed of oscillator in the stop vibration state , K is the release of the state , EL in normal lighting condition. When the mine Neiwa Si concentration in excess of limits , the sensor detects methane gas , which a black carrier catalytic component B produces gasification reaction temperature, the resistance decreases, the Vl conduction ability to enhance the , V5 conduction diminished capacity , V6 And V7 conduction , the oscillator oscillation , K intermittent turn , issued a " da da "sound, while EL flashing , to remind miners gas gas gauge .
RI-R18 used 1/4W metal film resistors or carbon film resistors .
RP use synthetic carbon potentiometers. Cl-C4 are selected voltage is 6.3 V or more electrolytic capacitors.
VDl and VD2 use 1N4007 or 2Cm2 type silicon rectifier diodes. VS selection 2CWll silicon voltage regulator diodes .
Vl-V5 , and V7 selected S9013 or 3DK4 silicon NPN transistor ; V6 used S9012 or 3CG2l silicon PNP transistor ; V8 and V9 are made of S8050 silicon NPN transistor .
K selected 4099 or JRC-5M DC relays. Sensor used Vector Catalytic gas sensors .
Power switch S, miner EL and battery GB for the original miner’s lamp accessories.