Propeller for distributing a gaseous, powdered or liquid material in a liquid

Apparatus for effecting mixing of material in a body of liquid comprising:

• a propeller having a hub and plural blades extending therefrom, each said blade having a tip and a leading edge and a trailing edge,
• said blade having immediately rearwardly of said leading edge a relatively thin, solid portion of chord-wise extent, a relatively thick hollow portion rearwardly of the said solid portion of small cord-wise extent and extending substantially to said tip from said hub, the blade lower camber being substantially planar, the blade upper camber being flat substantially from said leading edge and then rising to a line of maximum thickness rearwardly of the leading edge and close to the trailing edge and then falling, the upper camber being curved forwardly and rearwardly of the line of maximum thickness and having thereunder the said hollow portion, the blade having relatively great chord-wise extent forwardly of said hollow portion, and being substantially flat forwardly of said hollow portion, perforations in said blade communicating said hollow portion with the exterior of said blade, said perforations being down stream of the line of maximum thickness and in a line generally parallel to said line of maximum thickness, and passage means in said hub fluid connected with the hollow portion of each said blade.