Patent ID: 8475645
Filing Date: 2013-07-02
Classification: C02F

Abstract:
1. A method of removing scale from cooling water in a cooling water circulation route through which the cooling water is circulated, the method comprising: providing a cooling water circulation apparatus which includes: (i) a cooling device configured to cool cooling water; (ii) a cooling water circulation route including the cooling device, the cooling water being circulated through the cooling water circulation route; and (iii) an electrolytic device configured to perform electrolytic processing on the cooling water in the cooling water circulation route, wherein the electrolytic device includes: (a) the first electrode; (b) the second electrode; (c) an electrolytic bath for storing the cooling water; and (d) a voltage source for applying a voltage and a direct current between the first electrode and the second electrode, a first electrolytic operation which includes precipitating mineral contents in the cooling water on a surface of the first electrode immersed in the cooling water in the electrolytic bath by applying a direct current voltage between the first electrode and the second electrode; a second electrolytic operation which includes precipitating mineral contents in the cooling water on a surface of the second electrode in the cooling water in the electrolytic bath by applying a direct current voltage between the first electrode and the second electrode while the polarities of the first electrode and the second electrode are reversed relative to the polarities thereof in said first electrolytic operation; repeatedly and alternately executing said first electrolytic operation and said second electrolytic operation; a first discharging operation performed before each repetition of the first electrolytic operation and after each repetition of the second electrolytic operation, the first discharging operation including separating mineral contents from the second electrode by reversing the polarities of the first electrode and the second electrode relative to the polarities thereof in said second electrolytic operation, and discharging the water in the electrolytic bath and the separated minerals to waste; a second discharging operation performed before each repetition of the second electrolytic operation and after each repetition of the first electrolytic operation, the second discharging operation including separating mineral contents from the first electrode by reversing the polarities of the first electrode and the second electrode relative to the polarities thereof in said first electrolytic operation, and discharging the water in the electrolytic bath and the separated minerals to waste; computing the conductivity of the cooling water based on the voltage and the direct current between the first electrode and the second electrode at predetermined time intervals during the first electrolytic operation and the second electrolytic operation; and changing the cooling water in the circulation route when conductivity computed in said computing operation exceeds a predetermined value, wherein the electrolytic bath is disposed on a bypass route such that discharging the water in the electrolytic bath does not discharge the water in the circulation route.