Apparatus for mixing and blending constituents of a flow of

Abstract

The constituents of a flow of thermoplastics material or the like are mixed and blended by passing the flow through a mixing structure which defines an array of elongate side-by-side passages. The passages are not all alike in that at least some of them have configurations which taper along their lengths to degrees or in directions that differ from the configurations of others of the passages, whereby the flows of fluid which discharge from the differently configured passages do so at differing velocities. As the discharging flows of differing velocities recombine to form a common flow having a uniform velocity, a desirable type of mixing and blending action results. In preferred practice, adjacent ones of the passages are tapered oppositely along their lengths to converge or diverge such that fluid flowing through the converging passages is caused to increase in velocity, while fluid flowing through the diverging passages is caused to diminish in velocity. An enhanced mixing and blending effect is achieved by positioning a plurality of these mixing structures in series at spaced locations along the fluid flow path. Where the mixing structures are formed from a good heat-conducting material, they may be heated and used in cooperation with heated walls of the body which defines the fluid flow path to heat the material being mixed and blended to achieve a more thorough melting of its constituents.