Abstract: The aeration of dispersions, especially the aeration of fiber suspensions in a flotation apparatus 1, is performed with a ring injector 2 to which air is delivered through air feed ducts 11 in the mixing section 4. The annular gap forming in the ring injector 2 is thus aerated inside and out. The center core 7, which tapers in the direction of the greatest free cross section Q4 of the ring injector 2, is provided with a fin 56 which prevents the rotation of the dispersion.

Abstract: A knee joint prosthesis includes a C-shaped femur cap to be fitted onto a resected femur condyle. The C-shaped femur cap is made up of two arch-shaped parts spaced apart and connected by a relatively flat third part. Each of the arch-shaped parts has a different radius. The arch-shaped part with the larger radius has an oblong hole extending in the circumferential direction of the part. A shaft can be placed through the oblong hole from the femur into the tibia. In addition, a tibia cap can be fitted onto the plateau of the tibia.

Abstract: A valve assembly for controlling fluid flow, either of a single fluid or for mixing two different fluids such as hot and cold water, operates with a pair of interengaging valve plates having inlet orifices and outlet orifices defined therethrough actuated relative to each other to align the orifices to effect fluid flow. A chamber is defined on one side of one of the plates and a silencer disk is arranged within the chamber with spring means being provided to urge the silencer disk against one of the plates to effect closure of at least the inlet opening of the valve assembly. In operation, inlet fluid pressure operates against the force of the spring means to lift the silencer disk from the one valve plate to enable flow through the valve assembly.