English to Russian Tech/Engineering Chemistry; Chem Sci/Eng distilling column

Down-comer Back-up Flood:

Occurs when the pressure available for a given height of liquid and froth in the downcomer cannot overcome the total pressure drop across the tray This pressure imbalance causes the froth in the downcomer to start backing-up until it reaches the tray above, causing an increased accumulation of liquid on it. It requires high liquid and vapour loads

Also (from the table I have):

Hydraulic Data
% Jet-Flood (Active Area)
% Downcomer Flood
Dry Tray Pressure Drop
Pressure Drop per Tray
Pressure Drop per Tray
Downcomer clear liquid height
Downcomer Backup (% of TS + OW)
Weir Loading
Liquid crest over weir