Abstract: A screw-type fluid pump is provided with an elongate casing having a surface defining an internal fluid flow space and a screw within the flow path, fixed to the casing, and having a plurality of flights for continuously conveying fluid from an inlet on the casing to an outlet for appropriate disposition as the screw and casing are rotated. A conduit/torque tube extends through the screw in axially overlapping relationship with the casing over no more than one third the axial extent of the screw at the upper region of the casing. The conduit/torque tube establishes communication between a plurality of pockets between screw turns and the atmosphere to effect pressure equalization so that cavitation in the fluid flow space is prevented as the screw is operated. The conduit/torque tube also transmits the force from a rotary drive to the screw.

Abstract: A reactor for waste water including a vessel 10 having two elongated outer channels 26, 28 sandwiching an elongated inner channel 30 with all the channels 26, 28 and 30 being connected to each other at both opposed ends thereof, a gate 64 at one of the ends 18 and movable between a first position isolating the channel 26 from the channels 28 and 30 and a second position isolating the channel 28 from the channels 26 and 30, rotors 32, 34 for each of the channels 26, 28 for aerating waste water in the vessel 10 and for causing the waste water to flow in the corresponding channels 26, 28 as well as the inner channel 30, and a pair of effluent outlets 98, 100, located at the end 18 and spaced to be on opposite sides of the gate 64, each selectively operable to withdraw effluent from the the outer channels 26, 28 on the associated side of the gate 64.