The structure and principle of explosion-proof thermocouples are basically the same as those of prefabricated thermocouples. The difference is that the explosion-proof product junction box (housing) adopts a special explosion-proof structure in the design. The junction box is made of high-strength aluminum alloy die-casting, and the well has sufficient internal space, wall thickness, and mechanical strength. The thermal stability of the rubber sealing ring meets the national explosion-proof standards. So, when the explosive mixed gas inside the junction box explodes, its internal pressure will not damage the junction box, and the resulting heat energy cannot spread or explode outward.