This summary is primarily divided based on the equipment application category, temperature classification of explosive gas mixtures, and explosion-proof protection types.
1. Equipment Application Category
Explosive electrical equipment is classified by type as follows:
Category I: Electrical equipment for underground coal mines
Category II: Electrical equipment for all explosive gas environments except underground coal mines
Category III: Electrical equipment for explosive dust environments except coal mines
Category II electrical equipment is further subdivided:
IIA: Representative gas is propane, with a relatively low explosive level.
IIB: Applicable to the operating conditions of Category IIA equipment, with a medium explosive level; representative gas is ethylene.
IIC: Applicable to the operating conditions of Category IIA and IIB equipment, with the highest explosive level; representative gases are hydrogen and acetylene.
For Category III electrical equipment, it is classified by dust type:
IIIA: Combustible dust clouds
IIIB: Non-conductive dust
IIIC: Conductive dust
2. Temperature Classification of Explosive Gas Mixtures
Temperature classification is divided based on differences in the ignition temperature of explosive gas mixtures, as shown below:
T1: t<450°C
T2: 200° C<t≤300 ° C
T3: 135° C<t≤200° C
T4: 100° C<t≤135°C
T5: 85° C<t≤100° C
T6: t≤85°C
3. Explosion-Proof Protection Types
Explosion-proof protection types are designed for different purposes and environments, primarily including:
d: Flameproof enclosure
e: Increased safety
i: Intrinsic safety
m: Encapsulation
n: Type n
o: Oil-immersed
p: Pressurized enclosure
q: Sand-filled
s: Special type
t: Dust ignition-proof enclosure
4. Example of Ex Certification Marking
Taking the explosion-proof mark Ex db IIB T4 Gb as an example, its meaning is:
Ex: Indicates that the equipment is an explosion-proof equipment.
db: Indicates that the equipment is of flameproof enclosure type.
IIB: Indicates that the explosive gas environment for the equipment is Category IIB, with the representative gas being ethylene.
T4: Indicates that the maximum surface temperature group of the equipment does not exceed
135°C (T4).
Gb: Indicates the equipment protection level, with a high protection grade.
In summary, the division of explosion-proof protection grades is a comprehensive consideration process, which needs to integrate multiple factors such as equipment application category, temperature group of explosive gas mixtures, and explosion-proof protection type. In practical applications, the appropriate explosion-proof protection grade and equipment should be selected according to the specific explosive environment and equipment requirements.
For more information, please contact STS directly!
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