Abstract: Liquid collector trays (5) are disclosed for use in vertical towers (7) in which vapor (9) moves upward and liquid (11) moves downward. The liquid collector trays (5) employ elongated plates (13) which in certain embodiments include a primary liquid collector trough (15) and a secondary liquid collector trough (17). In other embodiments, the primary liquid collector troughs (15) of adjacent plates (13) are aligned so as to form elongated, inwardly-tapering entrance channels (29) which are free of sharp corners. In further embodiments, when the liquid collector tray (5) is in its operative orientation and is viewed from above, each plate (13) includes first and second concave surfaces (31, 33), which collect liquid, and third and fourth convex surfaces (35, 37), which are adjacent to the first and second concave surfaces (31, 33) and serve to mechanically stabilize the plate (13).