Patent ID: 8550690

Claim:
A method of dispensing a user-defined quantity of one or more additive liquids to a cementitious mixture comprising: (a) moving an additive liquid to a manifold; (b) moving said additive liquid from said manifold to a mass flow meter; (c) measuring the quantity of said additive liquid while said additive liquid is moving through said flow meter; (d) moving said additive liquid from said flow meter to said cementitious mixture; (e) optionally, repeating (a)-(d) for one or more additional additive liquids; (f) purging at least one of said manifold and said flow meter with a purgative fluid, wherein at least a portion of said purgative fluid is moved to said cementitious mixture; wherein at least a portion of said additive liquid is recirculated prior to moving said additive liquid to said manifold; and wherein there is substantially no accumulation of additive liquid in the manifold or any components downstream of said manifold.