防爆电器常识一：防爆原理

防爆电器常识一：防爆原理
1、引起爆炸的三个必要条件，三个条件同时具备 —— 爆炸 
    点燃源 source of ignition；氧气 oxygen；可燃物 combustible
2、防止爆炸的产生必从三个必要条件来考虑，限制了其中的一个必要条件，就限制了爆炸的产生。

防爆标准 Standard	防爆原理 Principle of explosion-proof	图解 IIIustration
隔爆型 d Flame-proof d IEC 60 079-1 EN 50 018	将设备在正常运行时，能产生火花电弧的部件置于隔爆外壳体，隔爆外壳能承受内部的爆炸压力面不致损失，并能防止爆炸传播到外壳外。 Parts which can ignite an explosive atmosphere are placed in an enclosure which, if there is an ignition of an explosive mixture internally, will withstand the pressure and prevent the explosion being transmitted to the atmosphere around the enclosure.
增安型 e Increased safely e IEC 60 079-7 EN 50 019	在正常运行时不会产生电弧、火花和危险高温，在结构上再进一步采取保护措施，提高设备的安全性。 Additional measures are taken to achieve a higher level of safety and avoid the risk of impermissibly high temperatures and the occurrence of sparks and arcs internally or on external parts of electrical equipment, which in normal use produce neither sparks, arcs nor dangerous temperatures.
正压型 P Pressurised apparatus P IEC 60 079-3 EN 50 016	保持内部保护气体的压力高于周围，以免爆炸性混合物进入外壳，或使足量的保护气体通过外壳，使内部的爆炸性混合物的浓度降至爆炸下限以下。 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 atmosphere, and if necessary, the interior of the enclosure is permanently supplied with protective gas so that there is dilution of flammable mixtures.
本质安全型 I Intrinsic safety I IEC 60 079-11 EN 50 020	设备内部的电路在规定的条件下，正常工作或规定的故障状态下产生的电火花和热效应均不能点爆炸性混合物。 The equipment placed in the hazardous area contains only intrinsically safe circuits. A circuit is intrinsically safe if no sparks of thermal effects occur under established test conditions (including the normal operating and certain faule conditions), which could lead to the ignition of a given explosive atmosphere.
充油型 O Oil immersion O IEC 60 079-5 EN 50 017	将电气设备的部件整个浸在保护液中，使设备不能够点燃液面上或个壳处面的爆炸性气体。 Electrical equipment or parts of electrical equipment are immersed in a protective liquid in such a way that an explosive atmosphere above the surface of outside the enclosure cannot be ignited.
充砂型 q Powder filling q IEC 60 079-5 EN 50 017	电气设备的一种防爆型式，将能点燃爆炸性气体的被固定导电部件完全埋入填充材料中，以防止点燃外部爆炸性气体环境。 Type of protection by which the equipment parts that could become an ignigion source are fixed in position and completely surrounded by finely ground solids, so as to prevent ignition of an external explosive atmosphere.
浇封型 m Moulding m IEC 60 079-18 EN 50 028	将可能点燃爆炸性混合物的部分浇封在复合物中使它不能点燃周围的爆炸性气体。 Parts which can ignite an explosive atmosphere are embedded in a casting compound so that the explosive atmosphere cannot be ignited.
无火花型 n Protection method n IEC 60 079-15 EN 50 021	电气设备不能点燃周围的爆炸性气体（在正常的工作条件下和在确定的非正常工作条件下）。 Electrical equipment is not capable of igniting a surrounding explosive atmosphere (in normal operation and under defined abnormal operating conditions).	2 区 Zone 2 n 型的几种保护方法 Several protection methods are subsumed under the protection type

防爆电器产品设计选型须如：
A、设计选型防爆电器产品时,可先参考防爆原理,定型对防爆电器:如隔爆型,增安型或本质安全型;
B、根据自己公司的场所参考防爆危险场所划分定义哪个区域如:爆炸性气体环境或可燃性粉尘环境;
C、据据公司危险场所的环境温度，参考防爆电器最高表面温度分组选取对应的温度组别；
D、以上对应技术参数确定后，防爆电器基本己定型。特需环境下，如环境比较潮湿，或周边有滴水等，默认的防爆电器防护等级己达不到要求时，客户在设计产品是须先注明IP防护等级表征。（相关护护等级可以参考：IP防爆等级定义）