Sieve tray design weep point

Figure IW Weep point prewure balance for sieve and valve trays, (a) Sieve tray (6] well-designed valve tray, (c) valve tray with too many velvet or with valves that are too light (d) valve tray with too many valves, but fewer than in C (a) well-designed valve trey with two valve weights. (From w. h. Haifa, Chem. Eng. Png., 72 (B), p 43 (September 1876), reprinted courtesy of the American Institute of Chemical Engineers.) 305... 

The above Fair s weep point method is applied to sieve trays. Bolles (1976) extended it to valve trays and details can be found in Bolles article. The weep rate is affected by minimum vapor loading in relation to weir loading, the number of holes for sieve tray, and the number of valves and weight of valves for valve tray. The experience shows that a well designed valve tray must maintain the weep point below the vapor loads at which the valve opens. To do this, a valve tray design should avoid use of too many valves. 

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