Principle for explosion-proof |
Standard |
Principle for explosion-proof protection |
Illustration |
Applying examples |
Flame-proof “d” |
It is a kind of electrical apparatus, which can bear the ignite mixture blasting inside of the shell, and keep good. Also it cannot ignite the explosive atmosphere formed by one or several kinds of gas or steam through any plane or structure hole |
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Explosion-proof breaker, switch,starter ,light, button, operating pole, electric cabinet, motor |
Increased safety “e” |
Additional measures are taken to achieve a higher level of safety and avoid the risk of impermissibly high temperature and the occurrence of sparks and arcs internally or on external parts of electrical equipment,which in normal use produces neither sparks ,arcs,nor dangerous temperatures. |
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EP junction box, junction box, threading box, transition case, flexible pipe, light, motor |
Pressurised apparatus “p” |
The formation of an explosive atmosphere inside an enclosure is prevented by using a protective gas to maintain an internal over pressure relative to the surrounding atmisphere, and if neccessary, the interior of the enclosure is permanently supplied with protective gas so that there is dilution of flammable mixtures. |
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EP analyzing room, large electromotor, eletricity distribution, meter controller |
Intrinsic safety “i” |
The equipment placed in the hazardous area contaions only intrinsically safe circuit.A circuit is intrinsically safe if no sparks of thermal effect occur under established test condition(including the normal operating and certain fault condition),which could lead to the ignition of a given explosive atomspohere. |
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EP communication equipment,sensor, adjuster, surveying and controlling equipment |
Moulding “m” |
Parts which can ignite an explosive atmosphere are embedded in a casting compound so that the explosive atmosphere cannot be ignited. |
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Explosion -proof transformer, resistor | |
Explosive mark examples |
3.1 ClassⅡB ,group T6 flame-proof explosive electric equipment, mark ExdⅡ BT6 3.2 Class Ⅱ ,group T3 increased safety explosive electric equipment , mark ExeⅡ T3 3.3 It adopts two types.First mark main explosion-proof type,then mark other explosion-proof type. The main body adopts incresed safety and built-in class Ⅱ C flame-proof EX parts,temperature T4, mark ExeⅡ CT4. 3.4 It adopts two types.First mark main explosion-proof type,then mark other explosion-proof type. The main body adopts flame-proof and connecting is increased safety , mark ExdeⅡ BT5. 3.5 Class Ⅱ ,group T4 pressurised apparatus explosive electric equipment , mark ExpⅡ T4. | |