CHILLED WATER/HOT WATER/CLOSED RECIRCULATING SYSTEMS – CORROSION INHIBITOR; ANTIFOULANT; MICROBIOCIDE
CW-L20-C is a unique and specialized mildly alkaline nitrite-based corrosion inhibitor for closed water circuits. It is available in a liquid and in a solid form (CW-S80-C). It contains the corrosion inhibitor, an internal indicator, a biocide and a hardness management compound. In its neat form the indicator is used to confirm that the product is suitably alkaline and when controlled at the required levels the indicator will reveal whether the pH in the circuit is adequate. At the required control limits the pH will not increase so as to affect amphoteric metals such as aluminium and zinc compounds harshly.
CW-L20-C is nominally dosed at between 2500-3000mg/l in the closed water system to maintain a residual as nitrite at between 300 – 400mg/l as well as an effective biocide residual. In chilled water circuits hardness salt precipitation is not highly problematic, however, in hot water circuits this may prove otherwise.
The initial dosage is the most critical. Thereafter water losses in chilled/cold closed water circuits is estimated to be between 8% to 12% per month; whereas, in closed hot water circuits the water losses average between 8% to 12% per week. Based on this and routine water analyses the CW-L20-C can be supplemented to the circuit as required.
There is a specific test method for the determination of the residual BCI-L20-C and/or the residual nitrite level. This is a titrimetric/colorimetric method and is immediately available.
CW-L20-C is also available as a spray dried powder – CW-S80-C and can be diluted to 25% m/m. The dosages and residuals can be controlled exactly as described above. Alternately the powder can be added to a recirculating system via the expansion vessel at 625 – 700 mg/l to maintain similar nitrite residuals. Product supplementation will be dependent upon the respective system water losses in each case.