Metal explosion-proof enclosure IIB and IIC specifications appearance difference

The classification of the explosion-proof box and the division of the explosion-proof box mark are often the expression and description of professional terms. However, the professional terms cannot be fully understood and understood by most procurement users. Therefore, today's article is mainly the language of popular introduction. The description is intended to give the customer a clearer understanding of the basic differences between the appearance of Class IIB explosion-proof enclosures and Class IIC explosion-proof enclosures.

Distinguish explosion-proof junction boxes/junction boxes and other explosion-proof fittings products are IIB class or IIC class, the more direct way is to look at the shape. In general, Class IIB is a rectangular flat cover, surrounded by screws. Most of the IIC grades are caps with a circular protrusion above the cube. Screwed top cover screwed up. Class IIC is the highest level of explosion-proof rating. Applicable to all explosive gas atmospheres except for downhole and flammable dust environment.

In the meantime, a lot of customers equate explosion-proof boxes with sealed boxes. It is believed that as long as the sealing performance is good, it is a good quality explosion-proof box. actually not. If so, then we will make all explosion-proof products into a sealed product is not finished? Take the example on the left side of the class IIB explosion-proof junction box. Between its upper and lower cover plates, there is a flameproof surface of the explosion-proof box between the flanges. The clearance of the flameproof surface is stressful. If our explosion-proof rating is IIBT6, then the requirement he has to meet is the explosion-proof joint clearance ≤ 0.5mm, temperature group T6. If we completely seal the explosion-proof box and use it in flammable and explosive places, in the event that there is a certain concentration of gas such as methane, the inside of the box itself will also generate heat. If there is a proper gap and the pressure reaches the tipping point, then the box will not Will detonate, if the seal is too good, flammable and explosive gas reaches a certain concentration, explosion-proof box pressure is too high, in case of an open fire spark will detonate the box.

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