Combustible gas alarm is composed of detector and alarm control host, widely used in oil, gas, chemical, oil depots and other combustible gases of petrochemical industry, used for leakage detection of indoor and outdoor hazardous locations, is an important instrument to ensure production and personal safety. When the measured exist combustible gas detector, gas signal into voltage signal and current signal to the alarm instrument, the instrument shows the percentage concentration of combustible gas explosion lower limit value. When the combustible gas concentration above the alarm setting value occurs when the sound and light alarm signal, personnel on duty to take safety measures, to avoid explosion accidents.
Note 1 Application
Combustible gas alarm fixed installation once in place, the position is not easy to change. On the basis of many years of accumulated experience, the specific application should consider the following points. (1) understand the monitoring device which may leak, factor analysis of their leakage pressure, direction, and draw the probe position distribution, according to the severity of leakage into Ⅰ, Ⅱ, Ⅲ three grades.
(2) according to the airflow direction, location, direction and other specific factors, determine when large spills, leakage of combustible gas in the direction of.
(3) according to the leakage gas density (greater than or less than the air), combined with the air flow trend graph trend, three-dimensional flow into leakage, and make initial point scheme in the downstream position of the flow.
(4) the leakage state leak is micro leakage or injection. If the micro leakage, then set up a position to close the leak some. If the spray leakage, will be slightly away from the leak point. These conditions, work out the final point scheme. So, need to purchase quantity and variety can be estimated.
(5) for the existence of large combustible gas leakage place, according to the relevant provisions of each distance of 10 20m should set up a detection point. For unattended small and not continuous operation of the pumping station, the need to pay attention to the possibility of combustible gas leakage, should install a detector in the wind.
(6) for a hydrogen leak location, should be installed in the upper plane of leak detector.
(7) for the gas density is greater than the air medium, should be less than the leak detector installed in the bottom plane, and pay attention to the surrounding environment characteristics. For easy accumulation of combustible gases places should be particularly Caution! Monitoring point.
(8) for open type combustible gas diffusion environment, if the lack of good ventilation conditions, can easily make the combustible gas content in the air of a site is close to or reaches the explosion limit concentration, these are safety monitoring point can not be ignored. According to the analysis results of on-site accident, more than half of them are caused by the incorrect installation and calibration. Therefore, it is necessary to note the installation and calibration of the right to reduce the fault.
Note 2 combustible gas alarm installation
(1) alarm around cannot have strong magnetic field has an effect on the instrument work (such as large power motor, transformer).
(2) alarm safety instrument, sound, light display function, should be installed in place to see the staff and easy to hear, in order to eliminate hidden dangers.
(3) alarm installation height should be in commonly 160 - 170cm, routine maintenance and repair personnel to facilitate.
(4) the alarm probe is the main contact combustion detection element for gas sensor, a platinum wire coil coated alumina and adhesive composition globose, outer surface with platinum, palladium and other metals. Therefore, in the installation must be careful, avoid damage the probe.
(5) different measured the density of the gas, the installation position of an indoor probe should also be different. The measured gas density is less than the density of the air, the probe should be installed in the 30cm direction from the roof down; conversely, probe, shall be installed at 30cm from the ground, direction.