Bubble cap column is a bell shaped cap which is fxed on the top of a cylindrical risers through which the vapor passes the tray deck. The cap column divert the vapor flow below the level of liquid on the tray deck where it is jetted into the liquid either through slots at the bottom of the cap or else between the skirt of the cap and the tray deck. The bubble caps facilitate the continuous contact between the rising vapors and returning liquid. This range is widely used in various food, beverages, alcohol and chemical industry. Structural characteristic of bubble cap tray ensures that the tray plate has no leakage basically. lt has relatively high flexibility.