
COLUMBIA BOILER COMPANY, REV 2-17
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ductance can be used to measure the total dissolved solids in the boiler water and to serve
as an accurate means for the control of solids through the use of blowdown.
Another test which is sometimes used as a gauge of solids is to measure the chloride pres-
ent in the boiler water. The ratio of chlorides in the boiler water to that of the feed water
can be used as a means to determine the amount of blowdown required. The chloride test
is unsuitable for feedwater with low incoming concentrations and the concentrations in the
feedwater must be averaged over time for accuracy.
High boiler solids will lead to foaming, priming, surging and carry over. These problems
can be overcome by proper, daily blowdown of the boiler.
Alkalinity
The alkalinity of boiler water should be sufficiently high enough to protect shell and plates
against acidic corrosion, but not high enough to produce carryover. A minimum value for
alkalinity for adequate protection is 200 PPM.
High boiler alkalinity, which is in excess of 700 PPM should be avoided. Values higher
than this can lead to embrittlement of the steel.
Phosphates
Phosphates are used to react with calcium hardness in the boiler water. In order for this
reaction to take place it is important to maintain a pH at a minimum value of 9.50. It is
desirable to keep the concentration of phosphates in the water to 30-50 PPM in order for
complete reaction of the phosphates with the calcium hardness entering the boiler through
the feedwater.
Hardness
The hardness of water is caused by calcium and magnesium ions which will vary greatly
throughout the country depending on the source of the water.
The hardness of the water can cause the formation of scale and sludge or mud in boilers.
The hardness must be removed in the makeup water to the return system. Total hardness
should not exceed 50 PPM.
Oils
Every effort should be made to prevent oils from getting into the boiler water. Oil causes
foaming, or combines with suspended solids to form a sludge which can cause the over-
heating of boiler plates. If oil does get into the boiler, the boiler should be taken out of
service immediately, and thoroughly cleaned.
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Страница 14: ... COLUMBIA BOILER COMPANY REV 2 17 11 Figure 4 BLOWDOWN PIPING ...
Страница 31: ... COLUMBIA BOILER COMPANY REV 2 17 28 MAINTENANCE LOG ...
Страница 32: ... COLUMBIA BOILER COMPANY REV 2 17 29 MAINTENANCE LOG ...
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