In the machining of aluminum and magnesium metals, there is a risk of dust explosion. The main reasons for this risk include the lack of necessary prevention and control measures for the dust removal system, or hot work in the dust explosion risk area, and the failure to clean up the dust deposit as required. To completely eliminate the risk of aluminum magnesium dust explosion, the following are what you should do.
Take necessary preventive and control measures for dust removal system
The first point is to pay attention to selecting the correct dust removal process. When using dry dust collectors for dust removal, bag type external filter dust removal or cyclone dust removal process must be adopted; When using wet dust collector for dust removal, water washing or water curtain dust removal process must be adopted.
The second point is that the dust removal system should be equipped with some hardware facilities that can prevent and control dust explosion according to the characteristics of dust explosion, such as setting up monitoring devices, and selecting one or more explosion-proof devices to reduce the explosion risk.
The third point is that the dust collector must work under negative pressure.
The fourth point is to ensure that the dust removal system cannot be connected with the air duct and equipment with combustible gas, high-temperature gas, smoke or other industrial gas, so as to avoid accidental ignition of dust.
The fifth point is to note that the air duct and dust collector of the dust removal system must not have sparks entering, but also pay attention to the cleanness in the air duct, and the dust accumulation thickness must not exceed 1mm. When designing the wind speed of the air duct, it is necessary to keep the dust concentration in the air duct not greater than 25% of the lower explosion limit, and the minimum wind speed is usually not less than 23 meters per second.
The sixth point is that the filter bag of dry-type dust collector must be made of filter material with flame retardant function and anti-static function, and its operation condition should be continuous ash unloading and continuous ash conveying.
The seventh point is that when designing and manufacturing the wet dust collector, the design of its water pressure and water consumption must be able to meet the requirements of removing the dust entering the dust collector. The circulating water should ensure that the water quality is clean. The water storage tank, water quality filter and water quality filter device should not be closed. Ventilation airflow should be set, and there should be no sediment and mud in the tank.
Code for safe operation in dust explosion hazardous areas
The first point is that hot work and inspection and maintenance operations are strictly prohibited in the operation area. If the above operations must be carried out, they must be carried out under the condition of completely stopping processing operations, and necessary fire safety measures must be taken for hot work.
The second point is that in the dust explosion risk area, the dust in the workplace and equipment and facilities should be cleaned in time, and the thickness of dust accumulation should not exceed 0.8 mm.
The third point is that during the cleaning operation, the cleaning method that does not produce dust and the cleaning tool that does not produce sparks should be adopted.
The fourth point is never to contact the dust collected by cleaning with rust, water or other chemicals or damp them, which is prone to exothermic reaction and spontaneous combustion. It should be put into containers made of non aluminum metal materials or anti-static materials with anti rust surface treatment, and stored in designated safe areas. The collected dust should be treated harmlessly.
The fifth point is that the safety operation regulations must be strictly observed during operation, and the tools used must ensure that there will be no collision sparks.
