Explosion-proof instruments

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Flameproofing, also known as pressure-resistant explosion protection, involves enclosing the instrument components that could ignite explosive substances within a specially robust enclosure. This enclosure is capable of withstanding the explosive pressure generated by the explosive mixture inside it, and it prevents the explosion from spreading outside the enclosure. In other words, an explosion may occur inside the housing of a flameproof instrument, but it will not spread outside. Therefore, strict explosion-proof requirements apply to various joints in such instruments – such as the number of thread turns on the instrument cover, the precision of the threads and their zero point, the gaps between the range adjustment screws and the instrument housing, the gaps between the sensing and conversion components of a transmitter, as well as the wire connections. Apart from being relatively bulky, flameproof instruments are otherwise simple and do not require associated equipment such as safety barriers. However, before opening the table cover, the power must be turned off first; otherwise, if sparks are generated, they will be exposed to the atmosphere, posing a danger.