Patent ID: 8246018

Claim:
Apparatus for diffusing gas into liquid contained in a basin, comprising: a diffuser assembly including a plurality of gas diffusers for applying gas to the liquid when the diffuser assembly is submerged in the liquid; a supply conduit for supplying gas to the diffusers; a buoyancy vessel connected with said diffuser assembly and presenting a chamber; and a gas line coupled with said chamber to selectively apply gas thereto, said diffuser assembly and buoyancy vessel being buoyant upon application of gas to said chamber to thereby effect buoyant ascension of the diffuser assembly to the surface of the liquid in the basin; wherein said chamber is substantially filled with liquid when the diffuser assembly is submerged; wherein the buoyancy vessel includes a flow control portion depending below a portion of the chamber, said flow control portion having a flow opening for discharging and admitting liquid to said chamber.