Present situation and future of explosion-proof motor for explosion-proof centrifugal fan

Explosion proof centrifugal fan is a centrifugal fan with explosion-proof measures and explosion-proof motor. The official name of the explosion-proof motor equipped with this kind of fan is explosion-proof three item asynchronous motor, which has a long history of application in our industrial enterprises. What is the current situation of this kind of explosion-proof motor and which direction it