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Explosion-proof electromagnetic stainless steel category

1. Explosion-proof electromagnetic stainless steel category, level and temperature group
1.1. Classification of Explosive Gas Environmental Hazardous Areas
Zone 0: A continuous or prolonged atmosphere of explosive gas mixtures.
Zone 1: The environment in which explosive gas mixtures may occur during normal operation.
Zone 2: In an environment where explosive gas mixtures are unlikely to occur during normal operation, or even in the presence of an explosive gas mixture that is present for a short time.
Zone 0: Generally only exists in closed gas tanks, storage tanks, etc. In the actual design process, Zone 1 is also rarely present. Most of the situations are in Zone 2.
1.2, explosion-proof electrical equipment is divided into two categories:
Class I Underground Coal Electrical Equipment
Class II electrical equipment used in places other than mines
1.3, Class II electrical equipment, according to its application for explosive gas mixture maximum test safety gap or minimum ignition current ratio, is divided into IIA, IIB, IIC three categories; according to the maximum surface temperature is divided into T1-T6 six groups. (IIC is the most advanced flameproof type, covering the application range of IIA and IIB
1.4. Explosive gas mixtures are grouped by ignition temperature, see Table 1.
1.5. Explosive gas mixtures are classified according to their maximum test safety clearance (MESG) or minimum ignition current ratio (MICR), see Table 2.
Table 1
Group ignition temperature T (°C)
T1 <450
T2 <300
T3 <200
T4 <135
T5 <100
T6 <85
Table 2
Category
Maximum test safety clearance
(MESG) (mm) Minimum ignition current ratio (MICR)
II A ≥0.9 >0.8
II B 0.5<MESG<0.9 0.45≤MICR≤0.8
II C ≤ 0.5 <0.45
2. Nouns
2.1. Flameproof electrical equipment The electrical equipment of the enclosure of electrical equipment that is capable of withstanding the explosion pressure of the internal explosive gas mixture and preventing the internal explosion from propagating to the explosive mixture around the enclosure is marked with “d”.
2.2. The safety-enhanced electrical equipment will not generate arcs, sparks or high temperatures that may ignite the explosive mixture under normal operating conditions. Measures are taken to improve the safety margin in order to avoid arcing, sparks or ignition under normal and recognized overload conditions. High temperature electrical equipment with the symbol "e"
Explosion-proof type sign Anti-explosion principle
Flameproof type d When the equipment is in normal operation, the parts that can produce spark arc are placed in the flameproof enclosure.
The explosion shell can withstand the internal explosion pressure without damage, and can guarantee the internal flame gas
When the body propagates through the gap, the energy is reduced, not enough to detonate the gas outside the shell.
Increased safety e. No arc, sparks and dangerous high temperatures during normal operation. Further structural
Take protective measures to improve the safety and reliability of the equipment.
Positive Pressure Type p Keep the pressure of the inner protective gas higher than the surrounding pressure to prevent the explosive mixture from entering the outer shell
Or enough protective gas passes through the enclosure to reduce the concentration of the explosive mixture inside
Fry below the lower limit.
The internal circuits of intrinsically safe i equipment are produced under normal conditions or under specified fault conditions.
Both raw EDM and thermal effects do not ignite the explosive mixture.
Encapsulant type m which will generate arcs, sparks or high temperature partial encapsulations that ignite explosive mixtures,
Make it unable to ignite the surrounding explosive mixture.

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