Patent ID: 8911138

Claim:
An apparatus for injecting liquids into a rotatable concrete mixer drum, comprising: a concrete mixer drum which is rotatably mounted to permit rotation about a rotation axis inclined at an orientation of 5-40 degrees relative to level ground and which has an oblong drum body with a inner circumferential wall connecting opposed first and second ends for defining a cavity within which to contain a fluid concrete; one of said two opposed ends of said oblong drum body having an opening to permit loading and unloading of concrete, and the other end being conformed to contain a nominal maximum concrete capacity such that a fluid concrete contained in the drum in the amount of 10%-30% of said nominal maximum concrete capacity presents an air/concrete interface having a first exposed surface area, designated herein as “ESA1,” and such that a fluid concrete contained in the drum in the amount of 70%-100% of said nominal maximum concrete capacity presents an air/concrete interface having exposed surface area, designated herein as “ESA2,” whereby ESA2 is greater than ESA1; a first conduit connected to a water source for introducing water into said mixer drum through said opening, said first conduit being aimed and mounted with respect to said drum opening, whereby 0%-100% of the water introduced through said first conduit into the drum would hit the air-concrete interface within ESA2; and a nozzle connected to a liquid chemical admixture source for introducing liquid chemical admixture into said drum through said opening, said nozzle being aimed and mounted with respect to said drum opening and having a nozzle aperture which is focused, whereby 75%-100% of the chemical admixture sprayed through said liquid chemical admixture nozzle into the drum would hit the air-concrete interface within ESA1.