MIXING MACHINES AND PARTS THEREOF, FOR THE MIXING OF LIQUIDS WITH SOLIDS, THE MIXING OF LIQUIDS OF VARYING VISCOSITIES, THE PREPARATION OF EMULSIONS, AND THE INTRODUCTION OF AIR INTO MIXTURES OR LIQUIDS, SAID MACHINES BEING FOR USE IN CHEMICAL, FOOD PROCESSING, OIL REFINING AND PAINT MANUFACTURING INDUSTRIES, AND BRICK AND TILE MAKING