Many  friends have seen explosion-proof power distribution box,  explosion-proof lamps, explosion-proof fittings and other products have  "EX" logo, yes "EX" on behalf of the meaning of explosion-proof, for the  explosion-proof shell can be divided into security type "Exe" And flameproof "Exd" two categories, where the difference between, and how to choose it?
One, the two different definitions:
1,  explosion-proof housing "d": an explosion-proof type of electrical  equipment, the shell can withstand any joint through the shell or  structural gap into the shell of the explosive mixture inside the  explosion without damage, and will not cause the outside by a Species, a variety of gases or vapors to form an explosive gas environment. (As defined in GB3836-2010)
  Simply said: a) shell can withstand internal explosion; b) shell can not be exploded after the explosion. The built-in components are common components.
2,  increased safety type "e": an explosion-proof type of electrical  equipment, that is, the electrical equipment to take some additional  measures to improve its safety, to prevent the normal operation or the  provisions of the abnormal conditions of the dangerous temperature, The possibility of.
  Simply  put: its internal itself does not produce dangerous temperatures, arcs  and sparks the possibility of just raising the safety level, such as  raising the degree of protection and so on. The built-in component must be marked with an Ex logo element (explosion-proof element).
Two, two are different shell structure type:
1, the explosion-proof "d" because of the need to bear the internal  explosion pressure, so it must be designed to release the energy of the  channel (simply is the flange surface), the average wall thickness than  the thick type.
2, increase safety type "e" because the internal itself does not  produce dangerous temperature, arc and spark the possibility, so there  is no flange surface.
Third, other:
1, only the flameproof type "d" and intrinsically safe "i" have ⅡA, ⅡB, ⅡC of the points; and increase safety type IIA, ⅡB, ⅡC.
2,  as a wiring ladder, explosion-proof "d" introduction device must be "d"  type (flameproof) introduction, the sealing ring than the increase in  the type of seal to be longer, increased safety-type device as long as  the access to improve its Safety level on the line.
3, explosion-proof "d" shell must do water pressure test (Ⅱ B 1.5MPa /  10 seconds water pressure, Ⅱ C grade 2.0MPa / 10 seconds water  pressure), and increase safety type is not required.
4,  explosion-proof "d" shell must do the impact test (to withstand the  quality of 1kg test object from the height of 0.7m vertical impact  test), increased safety shell does not do the impact test.