Knowledge of carbon monoxide alarm

Gas leak alarm is a very important gas safety equipment, it is the last protection for the safe use of city gas. The gas leakage alarm detects the low-concentration combustible gas in the surrounding environment through the gas sensor, and transmits the detection signal to the controller or control circuit with analog or digital quantities through the sampling circuit. When the combustible gas concentration exceeds the setting in the controller or control circuit At a fixed value, the controller sends out an alarm signal through the actuator or the execution circuit or performs actions such as closing the gas valve. Combustible gas alarm sensors for detecting combustible gases are mainly oxide semiconductor type, catalytic combustion type, hot wire type gas sensors, and a small number of other types, such as chemical battery sensors. These sensors are through the adsorption of combustible gas in the surrounding environment to produce chemical reactions or electrochemical reactions on the sensor surface, causing changes in the sensor's electrophysical properties.

Gas leak alarms can be divided into leak alarms with only leak alarm functions and detection alarms that can indicate the detected gas concentration and have alarm functions; from the use site, they can be divided into civil gas leak alarms and Commercial alarm. Civil alarms are usually independent gas alarms used in residential buildings with simple functions; commercial alarms mainly use gas transportation, storage sites, factories and public places that use gas and gas leaks. The city gas code stipulates that gas alarms should be installed in basements, semi-basements, gas-using rooms in closed spaces above the ground, pipeline wells in buildings, and closed meter rooms. The relevant codes and regulations of buildings and gas also recommend the use of civil gas leak alarms.

The use of gas leakage alarms greatly reduces the probability of major accidents due to gas leakage in places where gas equipment is used.

The most critical performance of the gas leak alarm is that it requires both high sensitivity to the detected gas and high stability and anti-interference. Because the sensors used for the alarms all have different degrees of "drift" tendency. Therefore, it is very difficult to manufacture high-performance and high-quality gas leak alarms. Pay attention to the following points when choosing to buy a gas leak alarm:

1. It should be purchased according to the type of gas used. Gas leak alarms are generally not universal. Use natural gas alarms for natural gas occasions, use artificial gas alarms for artificial gas occasions, and use liquefied petroleum gas alarms for liquefied petroleum gas occasions. General combustible gas detection alarm calibrated with liquefied petroleum gas (note: the gas composition in different regions is different, and the gas alarm that is calibrated and tested with the local gas composition should be used).

2. To buy gas leak alarms, you should choose products from reputable companies in the market. It is best to conduct a survey before buying, because on the one hand, the alarm products on the market are mixed, and users will not know this product very well; The device is a long-term product. When there is no gas leakage, the performance and quality of the period cannot be seen. Therefore, its long-term stability is very high. However, the current product standards for gas leakage alarms are still insufficient in evaluating their long-term stability. Therefore, the research and quality control of products by manufacturers are very important for the performance and quality of products. You can also learn about the use of the product from the long-term user and the test results of the gas alarm in use issued by the product testing unit over the years for reference.

3. The use of gas leakage alarms should pay attention to the long-term stability and service life of the alarms. The alarms, especially their sensors, have a lifespan. You should consult the seller and the manufacturer when purchasing. At the same time, due to the importance of gas leak alarms used in public places for safety, the Shanghai Gas Management Regulations just released require commercial gas leak alarms to be commissioned by professional inspection structures for regular testing to ensure their normal use.