This well-proven device is suitable for applications requiring high operational flexibility. It has been widely used since the 1950s, but it is becoming less common nowadays due to higher cost than the sieve and valve trays have.
The device can be liquid-proof or standard, with a wide range of materials and designs. Devices of this type provide very high flexibility in operating mode setting (10:1). Caps are available in diameters from 30 to 200 mm.