Mixer blade

Claim 1

An axial flow bladed impeller intended for exerting a stirring action in a fluid medium, the primary phase of which is liquid, contained in a vessel designed such that the configuration of the blowing zone can be forecast and calculated in order to optimize the efficiency of the mixing effect, by the action of generally centripetal secondary radial currents, said impeller having a rotational axis and plural blades spaced therearound, each said blade being formed of a trapezoidal sheet of material such that said blade has a constant thickness, each said blade having a leading edge and a trailing edge, taken in the direction of rotation of said impeller, all sections of each said blade formed at positions radially spaced from said rotational axis being curved, the distance between said leading edge and said trailing edge of each said blade continuously decreasing from said rotational axis to the outer blade tip, and for any given said section of each said blade there being an angle of incidence defined between a velocity vector of the fluid flow acting on said section and a straight line extending from said trailing edge of said section to a point on said section whereat a tangent to said section is parallel to said velocity vector, said angle of incidence for each said blade continuously varying and generally decreasing from said rotational axis to said outer blade tip.