Abstract: Apparatus and methods for mixing a liquid and a flowable treating agent wherein liquid from a body thereof is pumped through a conduit submerged in the body of liquid and having a constricting nozzle therein which produces low pressure zone downstream of the nozzle. A draft tube communicates with the conduit in the vicinity of the low pressure zone and directs the flowable treating agent into the conduit by suction for mixing with the liquid. The nozzle outlet has a plurality of radially spaced slots separated by solid land portions which together interact with the fluid discharged from the nozzle to produce multiple, axially spaced venae contractae in the fluid downstream of the nozzle to effect mixing of the liquid and treating agent.

Abstract: Apparatus for aerating a pool of liquid has a hollow, rotatable drive shaft journaled for rotation about an axis and coupled at one end to a driving motor. A propeller is mounted at the other end of the drive shaft. The propeller has a plurality of hollow blades in communication with an internal aerating fluid passage in the drive shaft. A plurality of air inlets is provided in the drive shaft and at least one outlet port is provided in each blade at the zone of highest negative pressure resulting from rotation of the blade in the liquid. The drive shaft automatically is movable from a dry-docked position in which the shaft is out of the liquid to an operating position in which the propeller blades are immersed in the liquid. A seal is provided between the propeller and the shaft journal to protect the latter against exposure to the liquid. The shaft is continuously pressurized between the journal and the seal to prevent liquid from passing through the seal should the seal become worn.

Abstract: Apparatus for aerating a pool of liquid has a hollow, rotatable drive shaft journaled for rotation about an axis and coupled at one end to a driving motor. A propeller is mounted at the other end of the drive shaft. The propeller has a plurality of hollow blades in communication with an internal aerating fluid passage in the drive shaft. A plurality of air inlets is provided in the drive shaft and at least one outlet port is provided in each blade at the zone of highest negative pressure resulting from rotation of the blade in the liquid. The drive shaft automatically is movable from a dry-docked position in which the shaft is out of the liquid to an operating position in which the propeller blades are immersed in the liquid. A seal is provided between the propeller and the shaft journal to protect the latter against exposure to the liquid. The shaft is continuously pressurized between the journal and the seal to prevent liquid from passing through the seal should the seal become worn.