Abstract: A dispersion water nozzle passes pressurized water containing dissolved air into a flotation clarifier. A throttle part of the nozzle is composed of a cylinder or spherical valve member, into which, the main flow through passage and a crosswise flow through passage are formed. The crosswise flow through passage has a smaller cross-sectional area. The throttle part is followed by a tubular flow equalization part. The nozzle is easy to clean by changing the flow passages and flow directions in the throttle member.