Knowledges of explosion-proof electrical equipment

Explosion-proof types are classified according to the environment in which explosion-proof electrical equipment is used, the characteristics of the product itself, safety and structure. They are flameproof, intrinsically safe, increased safety, encapsulated, positive pressure and oil-immersed. The most common type is explosion-proof electrical equipment, with the explosion-proof mark "d".

When the explosion-proof electrical equipment is in normal operation, the parts that can generate sparks, arcs and dangerous temperatures are placed in the flameproof enclosure to separate the equipment content space from the surrounding environment; when an explosion occurs inside, the enclosure will not be damaged, and the gap in the enclosure structure can also cool the flame and reduce the spread of flames, thereby achieving the purpose of explosion-proof.

The types of explosion-proof electrical equipment used in the following are:

Class I: coal mine gas

IIA: propane, methane, diesel, etc.

IIB: ethylene, ethylene glycol, etc.

IIC: acetylene, hydrogen, carbon disulfide, ethyl nitrate, etc.

Common explosion-proof joints of explosion-proof electrical equipment are:

Plane type: The upper and lower shells are matched in a plane to form a flameproof joint surface, so that the shell can withstand the pressure generated by the explosion of the internal explosive mixture and prevent the explosion from spreading to the explosive gas environment around the shell.

Threaded type: The upper and lower shells are matched in a threaded manner to form a flameproof joint surface, so that the shell can withstand the pressure generated by the explosion of the internal explosive mixture and prevent the explosion from spreading to the explosive gas environment around the shell.

Cylinder type: The upper and lower shells are matched in a cylinder to form a flameproof joint surface, so that the shell can withstand the pressure generated by the explosion of the internal explosive mixture and prevent the explosion from spreading to the explosive gas environment around the shell.

Bonding type: The parts of the flameproof enclosure are directly bonded to the enclosure wall, forming an inseparable component with it, or bonded to the metal frame so that the components can be replaced as a whole without damaging the bonding.

Main experiments for explosion-proof electrical equipment:

Test compliance standards: GB/T 3836.2-2021 Articles 15.2 and 15.3

Test item names: Enclosure pressure test, internal ignition non-propagation test, appearance inspection, flooding test, impact resistance test, heat and cold resistance test, flame ablation test, etc.