Apparatus and method for introducing liquid additives into a concrete mix

Apparatus for measuring liquid additives introduced into a concrete mix, comprising:

• a plurality of reservoirs of liquid additive;
• a measurement chamber connected to each of said plurality of reservoirs;
• first valve means connected to each of said measurement chambers for selectively venting each of said measurement chambers to atmosphere;
• a sensing tube disposed within each said measurement chamber, said sensing tube having a sealed top end opposite an open bottom end;
• a differential pressure transducer having a first sensor received within said sealed top end and a second sensor received within said measurement chamber;
• and
• control means interposed between said plurality of reservoirs and said differential pressure transducer for controlling dispensing of liquid additive from each of said plurality of reservoirs to each of said measurement chambers as a function of the pressure head within each respective said measurement chamber.

A method for supplying additives to a concrete mixing system, comprising the steps of:

• supplying a predetermined amount of concrete mix to a mixing tank;
• providing at least one reservoir of liquid additive;
• providing a measurement chamber connected to each respective said reservoir;
• receiving a sensing tube within each said measurement chamber for monitoring a preselected characteristic, said sensing tube having a closed top end;
• controlling the amount of liquid additive transferred from said reservoir to said measurement chamber as a function of said preselected characteristic;
• and
• transferring the liquid additive from said measurement chamber to the mixing tank for mixing with the concrete mix.