Patent ID: 8153010

Claim:
A method for controlling scale formation in a cooling water system, said method comprising the steps of: selecting a desired scaling index value indicating a desired degree of scaling or absence of scaling in the cooling water system; obtaining a sample of cooling water from the cooling water system; measuring a Ca 2+ concentration and alkalinity of the sample; calculating a setpoint pH based upon the selected scale index value and the measured Ca 2+ concentration and alkalinity; measuring a pH of the cooling water; and adding an amount of CO 2 to the cooling water based upon the setpoint pH and measured pH; the method further comprising the steps of: a) providing a cabinet enclosing: 1) first and second programmable logic controllers, the second programmable logic controller being written with an algorithm adapted to perform said step of calculating a setpoint pH, 2) a Ca 2+ concentration and alkalinity measurement device adapted and configured to perform said step of measuring the Ca 2+ concentration and alkalinity of the sample, 3) a pH probe adapted and configured to perform said step of measuring the pH of the sample; b) sending a signal corresponding to the measured Ca 2+ concentration and alkalinity from the Ca 2+ concentration and alkalinity measurement device to the second programmable logic controller; c) sending a signal corresponding to the setpoint pH from the second controller to the first programmable logic controller; d) sending a signal corresponding to the measured pH from the pH probe to the first programmable logic controller, wherein said step of adding comprises: 1) determining with the first programmable logic controller whether or not CO 2 should be added to the cooling water system based upon whether the measured pH is higher than the setpoint pH, and 2) adding the amount of CO 2 based upon said step of determining.