An integral collector-distributor device including chimney hats and adapted for use in a gas-liquid exchange column to promote radial mixing of a liquid on a distributor tray surface. The collector-distributor device includes a tray having a tray surface adapted to extend generally horizontally across the cross-sectional area of the column to collect downwardly flowing liquid. A plurality of gas risers on the tray permit the upward movement of an upwardly flowing gas through the tray, and a plurality of liquid distributors permit the generally uniform distribution of the collected downwardly flowing liquid to a lower section of the column. A plurality of chimney hats, each having an upper surface and a one and other end, extend over and above at least a portion of the gas risers, are angularly inclined from the horizontal, or are horizontal, collect downwardly flowing liquid on the upper surface and permit the collected liquid on the upper surface to flow away from the point of liquid collection to another section of the tray to promote improved liquid mixing across the tray surface and to reduce liquid concentration gradients on the tray surface. The chimney hats are of a selected width, wider that the width of the gas risers, to provide for minimal space between each adjacent chimney hat. The wide chimney hats, particularly where horizontal, may also be of different selected vertical heights to permit the upward flow of gas.