HI-TECH Rotary Air Locks designed for either manual or remote controlled drive, are used under silo deck slabs and bins to permit the free flow of pulverized materials which tend to arch, such as lime and cement raw materials. Free movement of the rotor to an opened or closed position is assured by careful machining and alignment of the trunnion shafts and dust-tight bearings. Leakage in the closed position is prevented by close tolerance and double seal. Knife edges and āvā slots at the end of the rotor avoid sticking of packed material.