A chimney tray for a column for thermal treatment of fluid mixtures, comprising a collecting tray and at least two chimneys (5-1, 5-2) spaced apart horizontally in the collecting tray , where each chimney (5-1, 5-2) forms a vertically aligned chimney body (6-1, 6-2) which forms a passage orifice (7-1, 7-2) through the collecting tray , and has a cover unit (8-1, 8-2) arranged spaced apart from the chimney body (6-1, 6-2), and where the cover unit (8-1, 8-2) covers the respective passage orifice (7-1, 7-2) in the vertical direction, and a screen which extends around the chimney body (6-1) of a first chimney (5-1), with the lower annular edge of the screen below the upper edge of the chimney body (6-1) of the first chimney (5-1) and the upper annular edge of the screen above the lower outer edge of the cover unit (8-1) of the first chimney (5-1) or adjoining the lower outer edge of the cover unit (8-1) of the first chimney (5-1), wherein the screen extends vertically downward from the lower edge of the cover unit (8-1) of the first chimney (5-1) to below the upper edge of the chimney body (6-1) of the first chimney (5-1), where the ratio (V4/V1) of the height (V4) of the chimney body (6-1) to the vertical distance (V1) of the upper edge of the chimney body (6-1) from the lower edge of the screen is within a range from 10 to 30; or the upper annular edge of the screen is above the lower edge of the cover unit (8-1) of the first chimney (5-1) and the screen is spaced apart horizontally from the cover unit (8-1), where the ratio (V4/V1) of the height (V4) of the chimney body (6-1) to the vertical distance (V1) of the upper edge of the chimney body (6-1) from the lower edge of the screen is within a range from 15 to 40. a collecting tray and at least two chimneys (5-1, 5-2) spaced apart horizontally in the collecting tray , where each chimney (5-1, 5-2) forms a vertically aligned chimney body (6-1, 6-2) which forms a passage orifice (7-1, 7-2) through the collecting tray , and has a cover unit (8-1, 8-2) arranged spaced apart from the chimney body (6-1, 6-2), and where the cover unit (8-1, 8-2) covers the respective passage orifice (7-1, 7-2) in the vertical direction, and a screen which extends around the chimney body (6-1) of a first chimney (5-1), with the lower annular edge of the screen below the upper edge of the chimney body (6-1) of the first chimney (5-1) and the upper annular edge of the screen above the lower outer edge of the cover unit (8-1) of the first chimney (5-1) or adjoining the lower outer edge of the cover unit (8-1) of the first chimney (5-1), wherein the screen extends vertically downward from the lower edge of the cover unit (8-1) of the first chimney (5-1) to below the upper edge of the chimney body (6-1) of the first chimney (5-1), where the ratio (V4/V1) of the height (V4) of the chimney body (6-1) to the vertical distance (V1) of the upper edge of the chimney body (6-1) from the lower edge of the screen is within a range from 10 to 30; or the upper annular edge of the screen is above the lower edge of the cover unit (8-1) of the first chimney (5-1) and the screen is spaced apart horizontally from the cover unit (8-1), where the ratio (V4/V1) of the height (V4) of the chimney body (6-1) to the vertical distance (V1) of the upper edge of the chimney body (6-1) from the lower edge of the screen is within a range from 15 to 40. <EOS>