There are generally two types of explosion-proof shell fasteners for explosion-proof lighting fixtures: flat and stop. For flat structures, bolts not only play a tightening role, but also ensure the clearance between the planes. For the sealing structure, when the explosion-proof surface only considers the cylindrical part, the bolt only plays a tightening role, while ensuring the clearance effect of the flat part. When directly threading on the casing, attention should be paid to not threading the fastener holes through the explosion-proof casing as much as possible. When threading through the casing, there should be a margin of 3mm or more at the bottom of the screw holes. When using lightweight alloy materials such as aluminum alloy for explosion-proof casing, due to the low strength of aluminum alloy, when using screws to tighten the explosion-proof casing that needs to be opened normally (such as changing the light source), threads should not be directly threaded on the aluminum alloy casing. Instead, pre embedded anti loosening inner and outer threaded steel sleeves should be used to increase the strength of the screw holes and prevent failure due to thread decay. Do not replace the light source or open the bolt that was already installed at the factory during maintenance. You can directly tap the fastening screw hole on the outer shell, but do not use fine thread. Try to use coarse thread and have enough engagement buckles to meet the fastening requirements.

In summary, when designing shell fasteners, it is preferable to distinguish the role of the explosion-proof shell. Is it only for tightening purposes, or is it for both tightening purposes and ensuring plane clearance, and then confirm that the appropriate bolt is selected for the maximum axial load of the bolt.

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