mounted inside the tube outlet and an internal annular flange
22 downstream of the flaplike member together with an
actuating mechanism for the valve which includes a float
member 23 disposed in the water W above the tube inlet 13
and a linkage assembly 24 connected between the float and
valve for pivoting the flaplike member in accordance with the
changes in the liquid level of the water W in the ditch D to
open and close the valve.