TM 5-810-15
(6) Demineralizers produce very high
either intermittent or continuous operation is used
quality water--higher than is generally required for
to control concentrations of dissolved solids. It is
a boiler operating at 400 psig.
connected to the stream drum of a water tube
boiler in such location as to minimize the inclusion
of feedwater, chemical feed and steam entrainment.
7-8. Blowdown tank.
The other blowdowns from the mud drum or the
a. Application. Pure water vapor is generated in
water walls are intermittent or mass blowdowns
a bailer and the impurities (dissolved solids) of the
which removes accumulated solids and sludge from
boiler feed water remain and become concentrated.
stagnated areas of the boiler, usually at reduced
The concentration of dissolved solids can be
steam loads. A blowdown tank allows the hot
controlled by withdrawing the boiler water with a
water to flash to steam leaving the concentrated
high concentration of dissolved solids as blowdown
impurities to be more safely drained to waste. The
and discharging it safely to waste through a
flashed steam can be vented to atmosphere or can
blowdown tank. Every boiler - system has two
be used in a heat recovery system.
types of blowdowns. The upper blow-down of
b. Design.
7-8
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