The rotary discharge valve, commonly known as impeller feeder, star feeder, air lock, rotary feeder, fan off, etc., is composed of a rotor with several blades, a shell, seals, an electric motor, a reducer, etc. When the rotor rotates within the cylindrical casing, the material falling from the upper hopper due to its own weight fills the space between the blades. As the rotor rotates to the lower part, it is discharged to achieve uniform and continuous conveying of materials.

The rotary discharge valve is a key equipment in the pneumatic conveying system. For positive or negative pressure conveying systems, the off fan can evenly and continuously supply material to the conveying pipe. The off fan is very suitable for positive and negative pressure pneumatic conveying systems, pulse dust removal equipment, and precision feeding situations. The closed fan has the characteristics of compact structure, beautiful appearance, good air locking performance, stable operation, uniform feeding, lightweight and energy-saving, and can play a role in feeding and locking the flow. Due to the low-speed rotation of the rotor and the small gap between the rotor and the inner cavity of the shell, it effectively prevents the reverse flow of air flow, thereby ensuring the stability of air pressure in the system and the normal discharge of materials.

There are various structural types of rotary valves based on the characteristics, uses, and usage conditions of the materials, and their selection depends on the characteristics of the conveyed materials, such as particle size, adhesion, temperature, humidity, etc.