Spill-way dam overflow - through mixing chamber and diffusor for creation of flotation zone in tail race

A spillway dam with an overflow over its crest is fitted with a vertical mixing chamber which starts with a water flow splitter and a distributor grid and terminates in a horizontal diffusor. Air intake openings near the grid ensure the formation of a flotation zone at the exit from the diffusion which extends up to a froth breaker in the tail race. This increases the air absorption of the part of the water passing through the mixing chamber and absorbs the kinetic energy of the water. It also purifies the water by removal of all oxidisable impurities.