MIL-HDBK-1003/6
Feeders.
Depending on various factors, select one of the following
7.4.2.3
feeders:
a)
A chemical feed proportioning pump that adjusts speed and
stroke,
b) Pot type feeders for dissolving chemical crystals, lumps, and
briquettes, as in (a) of Figure 29,
c) Pot type feeder for feeding alum and soda ash in proportion to
makeup flow, as in (b) of Figure 29.
Sample Coolers. Boiler water samples, taken from the boiler for
7.4.2.4
analysis, must be cooled to approximately boiler-room temperature in a sample
cooler. See Figure 30, for method of installation. The cooler should be
connected upstream of the continuous blowdown, or to the water column. One
cooler may serve two or more boilers. If possible, locate it near the
laboratory sink where tests for boiler water residuals are made.
Steam samples, taken from the boiler discharge header, must be
cooled to room temperature in a sample cooler. These samples are necessary to
determine the carbon dioxide and oxygen content of the steam, and for special
studies in connection with carryover, foaming, and priming, terms that
describe conditions causing the entrainment of the boiler water solids in
particles of water with the steam. If possible, provide a separate steam
sampling nozzle for each boiler. The installation is schematically shown in
Figure 30. The nozzle and method of connection should conform ASTM/ASME
Method D 1066, Sampling Steam. The preferred location with respect to
position in the order of decreasing preference is: (a) vertical pipe,
downward flow, (b) vertical pipe, upward flow, (c) horizontal pipe with
horizontal insertion, (d) horizontal pipe, with vertical insertion. The steam
sample cooler should be separate from that for boiler water, because otherwise
it is possible to mix in residual solids remaining from the water analysis.
All piping, connections and valves conveying the steam to the sample cooler
must be corrosion-resistant material such as stainless steel.
7.5
Ion Exchange Softening
7.5.1
Ion Exchange Water Softening. This method of softening is
generally used as the first step in makeup water treatment. A makeup water
analysis should be performed to determine the constituents in the water which
need to be handled by the treatment program. A typical makeup water analysis
form is included in Table 21. The treated makeup water is generally mixed
with returned condensate to provide the feedwater to the boiler. Refer to
Table 17. The choice of ion exchange material should depend on the end result
desired. Seek advice of qualified water treatment consultants for the proper
ion exchange materials.
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