1. What are explosion-proof electrical equipment?
The professional definition of explosion-proof electrical equipment refers to electrical equipment designed and manufactured according to prescribed conditions (explosion-proof type) without causing explosions of surrounding explosive mixtures (explosion-hazardous places). In short, it refers to an electrical equipment used in explosive environments.
The so-called equipment for use in an explosive environment refers to the general term for electrical explosion-proof equipment and non-electrical explosion-proof equipment used alone or in combination in an explosive environment that can prevent explosions due to its own potential ignition source.
2. What are the categories of explosion-proof electrical equipment?
According to the applicable explosive environment, it is divided into Class I, Class II and Class III. That is, explosion-proof electrical equipment categories are divided into: Class I: electrical equipment for coal mines, explosion-proof for mining; Class II: electrical equipment for explosive gas environments except coal mines, explosion-proof for gas plants; Class III: explosive dust except coal mines Electrical equipment for environment and explosion-proof for dust factories.
Class II equipment categories are further divided into: Class IIA: propane, natural gas, etc.; Class IIB: ethylene, ethanol, etc.; Class IIC: hydrogen, acetylene, etc.
Class III equipment categories are further divided into: Class IIIA: combustible flying catkins (such as artificial fibers, cotton, hemp catkins, etc.); Class IIIB: non-conductive dust (ρ＞1kΩ·m), Class IIIC: conductive dust ( ρ≤1kΩ·m).
3. What is equipment protection level EPL?
The protection level of the equipment is based on the possibility of the equipment becoming an ignition source and the different characteristics of the explosive gas environment, the explosive dust environment and the explosive methane explosive environment of coal mines.
Equipment protection level EPL-gas:
Ga: Equipment for explosive gas environments has a "very high" protection level and is not an ignition source under normal operation, expected faults or rare faults.
Gb: Equipment for explosive gas environments, with a "high" protection level, is not an ignition source under normal operation or expected failure conditions.
Gc: Equipment for explosive gas environments has a "general" protection level and is not an ignition source during normal operation. Some additional protection measures can also be taken to ensure that the ignition source is often expected to occur (such as lamp failure) will not be Form effective ignition.
Equipment protection level EPL-dust:
Da: Equipment for explosive dust environments has a "very high" protection level and is not an ignition source under normal operation, expected faults or rare faults.
Db: Equipment for explosive dust environments, with a "high" protection level, is not an ignition source under normal operation or expected failure conditions.
Dc: Equipment for explosive dust environments has a "general" protection level and is not an ignition source during normal operation. Some additional protection measures can also be taken to ensure that the ignition source is often expected to occur (such as lamp failure) will not be Form effective ignition.
4. What is the classification of explosion-proof electrical usage areas?
In the use area of gas: it is divided into zone 0, zone 1, and zone 2.
Zone 0: a place where explosive gas environments appear continuously or exist for a long time;
Zone 1: A place where explosive gas environments may occur during normal operation;
Zone 2: During normal operation, an explosive gas environment is impossible. If it occurs, it will also occur occasionally and only exist for a short time.
In the use areas of dust: divided into areas 20, 21 and 22.
Zone 20: Places where combustible dust clouds in the air persist, long-term or frequent and short-term in explosive dust environments;
Zone 21: In normal operation, it is likely that it is occasionally present in an explosive dust environment in the form of a cloud of combustible dust in the air;
Zone 22: In normal operation, it is unlikely that a place that exists in an explosive dust environment in the form of a combustible dust cloud in the air, if it exists only briefly.
5. Explosion-proof type and explosion-proof principle of explosion-proof electrical appliances
6. Understanding of explosion-proof signs
