To be used under negative pressure conveying cyclone, it adopts detached foundry, of which all components have been precisely processed before assembling. It has exquisite configuration and anti-blocking design, which can solve material stuck problem without dismantling. The hole at the end of bearing is for observing sealing efficiency at any time, and the observation window on the top is for to following up the process of discharging. This type of valve offers series connection solution, using single power to drive multi-valves. Ultimately, it can save energy and reduce purchasing cost.