Abstract: An enclosed-rotor vertical-shaft rotary valve is used as an airlock to inject abrasive, fine, or sticky solids into pressurized air. The invention eliminates the effect of thermal expansion on the gap between the rotor and casing, thereby making it possible to obtain much smaller gaps than before. The smallness of the gaps makes it feasible to pump clean air into the gaps without interfering with the performance of the airlock. The clean air keeps dust-laden air from entering the gaps, which eliminates the erosion that has limited the usefulness of conventional rotary valves when handling abrasive powders. By the use of two vents and a dual-pressure purge-air system, the invention also greatly reduces the blowby of air into the entrance of the airlock, which has limited the usefulness of conventional rotary valves when handling very-small-particle powders. These benefits also accrue to the injection of sticky solids into pressurized fluids.

Abstract: A rotary valve including a rotor assembly rotatable by a driver to cause material to be transferred from an inlet side to an outlet side of the rotary valve. The rotor assembly includes a rotor coupled to a shaft which rotates about an axis when driven by the driver. The rotor includes an outer tube, an inner tube, and a plurality of radial blades. The rotary valve includes a casing assembly for supporting the rotor assembly that includes an inlet for allowing the material to enter pockets of the rotor assembly and an outlet for allowing the material to exit the rotor assembly. The casing assembly includes an upper cap disposed at a top of the casing assembly that contains an opening for allowing the material to enter the pockets of the rotor assembly, a shaft opening, and a wiper assembly that removes material from the tops of the blades as the blades pass by the inlet opening.