Bubble cap tray is Intermediate solution between sieve and mobile valve trays Vapor rises through risers or uptakes into bubble cap, out through slots as bubbles into Surrounding liquid on the tray.
It is mainly used in special applications.
(+) Suitable for fouling services – Higher capacity compared with sieve trays (10-15%)
(+) Slightly higher efficiency and flexibility compared with Sieve Trays
(-) Cost is comparable with valve trays