SECTION 11
SPECIFICATIONS
Jan 2003
p. 11-4
05130653
Cutting Water Specifications
The cutting water supply to the waterjet pump must meet the following specifications.
High concentration of dissolved solids, especially calcium, silica, and chlorides, will
affect high pressure component life. A water analysis will indicate the type of water
treatment necessary.
Water Quality Parameters
Minimum
Requirement
Better Best
Alkalinity (mg/l) 50 25 10
Calcium (mg/l) 25 5 0.5
Carbon Dioxide (mg/l) 0 0 0
Chloride as Cl (mg/l) 100 15 1
Free Chlorine (mg/l) 1 1 0.05
Iron as Fe (mg/l) 0.2 0.1 0.01
Manganese as Mn (mg/l) 0.1 0.1 0.1
Magnesium as Mg (mg/l) 0.5 0.1 0.1
Nitrate (mg/l) 25 25 10
Oxygen (mg/l) 2 1 0.1
pH Value 6.5 - 8.5 6.5 - 8.5 6.5 - 8.5
Silica (mg/l) 15 10 1
Sodium (mg/l) 50 10 1
Sulfate (mg/l) 25 25 1
Total Dissolved Solids (mg/l) 200 100 5*
Total Hardness as CaCO3
(mg/l)
25 10 1
Turbidity (NTU) 5 6 1
* Do not reduce beyond this amount or the water will become too aggressive.
Cooling Water Specifications
Depending on the type of cooling system (closed recirculation, once through,
etc.), the following common problems can be experienced:
Closed recirculation:
Corrosion
Fouling
Once through:
Corrosion
Fouling
Scale
Microbiological
Scale control is the most common problem, and is the result of insoluble matter
deposited on the heat transfer surface. Calcium carbonate is the primary cause of
scale when calcium bicarbonate breaks down. As the temperature of the water
increases it becomes less able to hold carbonates in suspension.
To predict the tendency of scale formation, the Langelier's saturation index can
be used as a guide.
Saturation Index = pH-pHs where pHs is calculated at saturation with calcium
carbonate.
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