A REACTOR

摘要

A reactor for aerating a fluid with a gas comprises a mixing tank (12) for t he fluid and a centrally located vertical draft tube (13) submerged in the fluid to divide the mixing tank (12) into an inne r chamber (21) and an outer chamber (23). The reactor further comprises a motor driven axial flow impeller (14) located in the dra ft tube (13) for circulating fluid downwardly through the inner chamber (21) and upwardly through the outer chamber (23). The reactor further comprises an external circuit for withdrawing a portion of the fluid from the mixing tank (12), aerating the fluid and returning the aerated fluid to the mixing tank (12). The aerator is in the form of a venturi device (17).