Explosion protection is used to protect all sorts of equipment or product against internal and external explosions & weather protection.
Basic methods of protection, it's used mainly in Hazardous Area
1. Explosion Containment 2.Segregation and 3. Prevention
Explosion containment: The only method that allows the explosion to occur but confines it to a well-defined area, thus avoiding the propagation to the surrounding atmosphere. Explosion-proof enclosures are based on this method.
Segregation: A method that attempts to physically separate or isolate the electrical parts or hot surfaces from the explosive mixture. This method includes various techniques, such as pressurization, encapsulation, etc.
Prevention: A method that limits the energy, both electrical and thermal, to safe levels under both normal operation and fault conditions. Intrinsic safety is the most representative technique of this method.
Explosion containment: The only method that allows the explosion to occur but confines it to a well-defined area, thus avoiding the propagation to the surrounding atmosphere. Explosion-proof enclosures are based on this method.
Segregation: A method that attempts to physically separate or isolate the electrical parts or hot surfaces from the explosive mixture. This method includes various techniques, such as pressurization, encapsulation, etc.
Prevention: A method that limits the energy, both electrical and thermal, to safe levels under both normal operation and fault conditions. Intrinsic safety is the most representative technique of this method.
Most Used Protection Type
Flame proof enclosure Ex d
This is strong enough to withstand internal explosion. This design allows internal ignition sources, like sparks and (limited) hot spots.
Pressurized enclosures Ex p
This is keep dangerous atmosphere outside by overpressure.
Powder (quartz) filling Ex q
This is extinguish any ignition source in a quartz filled enclosure.
Increased safety Ex e
This is increased safety level for normally non sparking apparatus. This design does not allow any (unprotected) sparking components inside.
Intrinsic Safety Ex i
This is limitation of energy in the whole electrical circuit.
Non Incendive Ex n
Ex n consists of several sub types of protection.
Moulded encapsulation Ex m
This is moulding of the electrical circuit.
Optical radiation Ex op
This is safety by either limitation of radiation or protection of optical light.
Protection by enclosure Ex t (for dust only)
This is minimum IP degree for dust tight enclosure (minimum IP rating of either IP5X or IP6X).
Equipment Protection Level
Where
G for Gas
a for Very High Safety Level
b for High Safety Level
c for Normal Safety Level
D for Dust.
How to read the markings?
Ex db eb IIC T6 Gb
Ex : Explosion protected.
db : Flameproof ’d’ with level of protection ’b’.
eb : Increased safe ’e’ with level of protection ’b’.
IIC : Group IIC
T6 : Max. surface temperature classified T6 (85°C).
Gb : This whole assembly has EPL Gb (zone 1).
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