Explosion-proof union

Explosion-proof union joints have a certain sealing function that prevents harmful gases and flammable or explosive gases from entering them (providing relative sealing); in the event of a fire source caused by factors such as poor contact, they can help prevent the spread of those gases. This must be carried out as required; otherwise, the safety supervision department will intervene.

If it is used for cable protection tubes, for the connections in the middle section, your understanding is correct. It merely serves a connecting and protective role. Just ask a rhetorical question and you’ll understand. How should the interface from the protection tube to the junction box be explained? Do all the trough boxes also need to be sealed and explosion-proof? A trough box comes in trough-type, ladder-type, and perforated types, right?

Whether a wire conduit joint needs to be explosion-proof depends on the application. The explosion-proof requirement for conduit pipes is that if one end of the conduit is in a fire, any combustible gas remaining inside the pipe cannot explode and spread out from the other end. This is actually only meaningful when the wire conduit extends far away from the junction box. Although it is classified as the highest level overall, within the same device the division of explosion-proof areas varies. Generally, in explosion-proof zones 0 and 1, the trunking runs along the edges of these zones, while cable conduits that extend into the interior of the zones must use explosion-proof connectors ； In Zone 2 or non-explosion-proof areas, the trunking extends deep into the area, and explosion-proof connectors are not required for the conduit. There doesn’t seem to be much difference in terms of whether a wire connection is explosion-proof or not, but explosion resistance is the result of certification. Personally, I prefer using explosion-proof connectors, as their construction and thickness make them more reliable compared to those products that do not have certification.

The problem is that when a protective tube is used to connect to the gauge head, there are generally two ways of doing this. One method involves using threaded connections, but these are not continuous, so there is no true sealing effect. The other method uses flexible connectors, but sealing devices are still needed at both ends of such flexible tubes. What plays a key role in preventing explosions is the sealed gland or sealing device. Regarding the summary on protective pipes, what explosion-proof effect can so-called explosion-proof joints actually provide?