Abstract: A venturi-type mixer that produces an aerated water jet for spas, therapy pools, swimming pools and the like is provided with a pulsating action by means of a rotating flow disturbing blade mounted at the discharge end of the jet nozzle to repetitively intercept the increased velocity stream discharged by the nozzle. The flow disturbing blade has its velocity controlled and adjusted by means of a water-driven turbine rotor journalled upstream of the nozzle and geared to the flow disturbing blade. The amount of projection of the turbine rotor blades into the water stream is varied by changing the relative alignment of non-circular input passage to the jet nozzle with respect to a congruent non-circular input passage from the main water supply.

Abstract: A venturi type mixer that produces an aerated water jet for spas, therapy pools, swimming pools and the like, is provided with a pulsating action by means of a flow impeding spoiler that momentarily and repetitively disturbs the water jet that is projected into the mixing chamber. Disturbance of the jet effectively disables the vacuum produced by the venturi action to thereby cause discharge of a water stream of decreased velocity having considerably less entrained air. The spoiler is moved into and out of the water jet by means of an automatically reciprocating piston that is operated by a combination of a spring and the vacuum produced by the venturi action. Alternatively the spoiler may be rotated into and out of the path of the jet by a water driven rotor, or the jet orifice may be rotated relative to a fixed spoiler.