Semiconductor gas sensors can be effectively used for the detection of methane, ethane, propane, butane, alcohol, formaldehyde, carbon monoxide, carbon dioxide, ethylene, acetylene, vinyl chloride, styrene, acrylic acid and many other gases. In particular, the sensor cost is low, suitable for civil gas detection needs.

Multi gas detector is a kind of single gas detector or multiple gas detectors that can be flexibly configured. It can be equipped with oxygen sensor, combustible gas sensor, toxic gas sensor or any four gas sensors or any single gas sensor.
The principle of the detection part of the four-in-one gas detector is that when the concentration of combustible gas measured exceeds the limit value, the amplified bridge output voltage and the circuit detection set voltage are passed through the voltage comparator and the square wave generator to output a group of square wave signals, control the sound and light detection circuit, the buzzer generates continuous sound, the led shines, and the detection signal is sent out.

To prevent gas leak explosion accidents this needs us to install use gas alarm system to detect the concentration of the gas, gas alarm is the main function of leakage detecting gas concentration, once reaches a certain concentration of gas leakage, gas alarm automatically audible and visual alarm to remind staff to take corresponding measures in time, to avoid the occurrence of major accidents. As an important security device, the alarm value of natural gas alarm is generally divided into one level and two levels. Today we are mainly to explain why the natural gas alarm should be equipped with two-stage alarm. What are the benefits?

First of all, it is necessary to know which gas can be measured, including methane, isobutane, propane, hydrogen, benzene, ketone and alcohol. Secondly, the concentration of the measured gas is determined. Generally, the lower explosive limit (%LEL) is detected in most cases. Note: the lower explosive limit of different gases is different. There are also partially detectable parts per million (PPM) levels, with 1%=10000ppm. If it's %LEL, the range is 0-100%LEL; If it's PPM, it's usually 0-100ppm or 0-1000ppm.

The reasons for the failure of the portable combustible gas detector are very complicated. In general, the main reasons are that the user does not understand the performance of the detector, the equipment is not properly selected, the user is not properly used, the construction is not in accordance with the requirements of the specification, and the maintenance is not enough. ATO summarized the following points:

The use environment and purpose should be taken into consideration before selection of a suitable monitoring equipment. The four-in-one gas detector, apart from being capable of mass data collection, real-time transmission, processing and display, should also take factors, such as temperature and pressure, influencing its adaptation to the environment under the well into consideration.

It is necessary to learn about the reserved value of the gas detector. The value marked on the equipment is the reserved value. If the reserved value displayed on the gas detector ranges from 50% to 70% of the gas concentration, then we should change the sensor of the gas detector. Therefore, it is tremendously important to change the gas detector's sensor immediately to avoid influencing our normal use of the gas detector.

According to judgment of the operation personnel, the gas nearby the sensor is fresh, and cannot exist normally. At the moment, the indication of the instrument is close to zero (reading). The zero-point setting process can be skipped. If there is any question, the plastic bag can be used to obtain the air nearby the sensor which is believed to be fresh. This is a very fast and easy process, and this method is very effective to distinguish the real alarm from the false alarm.

The indication error mentioned above is found with the permissible error as to the alarm level of the gas detector. Since the instrument might be influenced by different factors, it is impossible to raise the alarm at a correct concentration. Therefore, the concentration level for alarm is allowed to have error, as long as the error is within the standard scope. The error for alarm of different gases is different. For example, the oxygen error which will raise alarm is within ±0.1% VOL.

Sometimes, the instrument might be in fault for working for a long period of time or in summer when the operating environment temperature is high. Every part is normal when the instrument is turned off for inspection, and the instrument can operate normally after a period of time. The phenomenon is caused in poor performance of some IC pieces or components, which cannot meet requirements of the high-temperature resistance index. In order to find out the causes, you can adopt the temperature rise and fall method.

Calibration of the gas detector is a precision detection. To detect whether the alarm can work normally, and whether its calibration and maintenance are the same should be implemented in time and in line with corresponding regulations. Only in this way can the alarm work consistently under a precise state. Sensitivity and responsiveness of the alarm can also be detected. The combustible gas detector is an alarm to detect gas leakage. It is usually used in the chemical plant, petroleum plant, gas station, and metallurgy plant, where gas leakage is common to see. These places have high-density combustible gases, so more attention should be paid to calibration of the detector.

The toxic gas alarm is made up of the detector and the alarm control main engine. Currently, it has found wide applications in the petrochemical industries, including petroleum, fuel gas, chemistry, and oil depot. It can be used to detect the leakage of indoor and outdoor dangerous occasions and is an important instrument to ensure production and personal safety. When the site is detected with toxic gases, the detector will transform the gas signals into the voltage signals or current signals, and send them to the alarm instrument. The instrument will display the concentration percentage of toxic gases' lower explosive limit. When the toxic gases’ concentration exceeds the set alarm level, a sound-light alarm signal will be generated. Under the condition, the personnel on duty should immediately adopt safety measures to avoid combustion and explosion.