There are two types of bolt-tight flameproof enclosures: flat and stop. For the plane structure, the bolt not only fastens, but also guarantees the plane clearance. For the stop-head structure, when only the cylinder part is considered for the flameproof surface, the bolt only plays the role of fastening. When the flaring surface of the cylinder needs to be added to the plane, the bolt not only plays the role of fastening, but also plays the role of ensuring partial clearance of the plane. When directly tapping the thread on the shell, it must be noted that the screw hole of the fastener should not go through the flameproof shell. When passing through the shell, there should be a margin of more than 3mm at the bottom of the screw hole. Flame-proof in use light alloy materials such as aluminum alloy shell, due to the low strength of aluminum alloy, therefore, often open, such as replacement light source need to open the flame-proof shell using screw fastening, should not be directly on the aluminum alloy shell tapping screw, should through the embedded locking rebar set inside and outside, to increase the strength of screw hole, and to prevent failure due to thread rotten teeth; It does not need to be opened by the user in the replacement of the light source or maintenance, and the bolts have been installed at the factory, can directly attack and tighten the screw holes on the shell, but can not use fine thread, try to use coarse thread, and have enough mesh number to meet the requirements of fastening. In a word, in the design of shell fasteners, should first distinguish its role in the flash-proof shell, is only the role of fastening, or both play a role in securing the plane gap at the same time, and then determine the bolt zui large axial load to choose the appropriate bolt.
The introduction of cables and wires can be connected in the following two ways:
A) indirect introduction, connected by a junction box or a plug-in device;
B) direct introduction, connecting the cable and wire directly to the main housing. It is worth noting that the sealing ring aging or pressure is not tight can directly produce combustion or explosion.