1、 Explosion hazards of combustible dust
When it comes to explosions, people always naturally think of explosives or flammable gases with oxygen(Or air)The deafening roar of an explosion. Little did they know, the drifting dust suspended in the air could also cause a powerful explosion. Dust explosion accidents are not uncommon both domestically and internationally, with recent incidents such as the Kunshan metal dust explosion and the Taiwan amusement park flour explosion.
Why does dust explode? In a certain enclosed space, when combustible dust is suspended in the air and reaches a certain concentration, it forms an explosive mixture. Once encountering Mars, it may cause rapid combustion and explosion. Common dust explosions include pulverized coal, flour, wood flour, sugar powder, corn flour, potato flour, dried milk powder, aluminum powder, zinc powder, magnesium powder, sulfur powder, etc. But as long as we strengthen our preventive measures, such explosions can still be completely avoided. If effective ventilation and dust removal measures are taken, smoking and open flame operations are strictly prohibited. Install pressure relief valves or other devices on the equipment casing, and use explosion containment systems, etc. Below we will briefly introduce how the polishing wet dust removal equipment in combustible dust areas achieves explosion-proof technology.
2、 Application of Polishing Wet Dust Removal Equipment in Explosive Dust Environments
Polishing wet dust removal equipment is generally used in processing sites for polishing magnesium alloys, aluminum, zinc, iron, etc. Due to the large amount of metal dust generated during the processing in such places, the dust combines with the air to form an explosive environment. Once it encounters an ignition source, it is easy to cause an explosion. So, it is required that the dust removal equipment itself has explosion-proof certification.
Polishing wet dust removal equipment is a pumpless pneumatic dust collector that does not require the use of any filtering materials throughout the entire water circulation process. The overall structure of the dust removal chamber and water gas separation chamber has no dead corners for dust accumulation, is observable, can be cleaned at any time, and has good air circulation safety performance.
The main structure of the dust collector is composed of a box body, a centrifugal fan, an electrical control box, a lighting lamp, an explosion-proof motor, a muffler, and a differential pressure gauge.
Its working principle is to bring dusty gas into close contact with liquid (usually water), and to use the inertial collision of water droplets and particles or the sufficient mixing effect of water and dust, as well as other effects, to capture particles or increase or retain particles in a fixed container to achieve the separation effect of water and dust.
The wet dust collector produced combines water bath and spray forms into one. Firstly, the suction force of a high-pressure centrifugal fan is used to press the dusty gas into a water tank filled with water at a certain height, and the water bath will adsorb some of the dust in the water. After uniform distribution and diversion, the gas flows from bottom to top, while the high-pressure nozzle sprays water mist from top to bottom to capture the remaining dust particles. Its filtration efficiency can reach85%above.
3、 Technical requirements for explosion-proof certification of polishing wet dust removal equipment
In such dust explosion prone areas, polishing wet dust removal equipment is often relatively large and may be composed of many components. The explosion-proof of dust removal equipment first requires all electrical components to be explosion-proof, such as motors with explosion-proof certificates, lighting fixtures, electrical control boxes, etc. It should be noted that the hazardous source involved in dust collectors is explosive dust, so the purchased components must also be dust explosion-proof or gas dust mixed. Some manufacturers often overlook this when purchasing components, using lighting fixtures that are only suitable for explosive gas environments.
In addition, due to the special nature of dust collectors, in addition to meeting explosion-proof standardsGB/T 3836The relevant requirements must also meet industry standardsAQ 4273-2016Safety Technical Specification for Dust Removal Systems Used in Dust Explosion Hazardous Areas. Including structural inspection of dust collectors, abnormal operation alarms, and the need to activate interlocking devices simultaneously for alarms.
4、 How to apply for explosion-proof certification for polishing wet dust removal equipment?
1. List of materials provided: copies of valid explosion-proof certificates for each live component, assembly drawings, schematic diagramsBOMTables, product manuals, enterprise standards, copies of business licenses, application authorization letters, etc.
2. Certification method: on-site evaluation and evidence collection method. Due to the large size of the equipment and the inconvenience of customers sending samples, we directly dispatched engineers to the customer's site to conduct product testing and evaluation, identify and assist in rectifying non-conforming items on site, greatly reducing the time for customers to obtain evidence and saving costs.
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