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|  MIL-D-18641F(SH)
3 . l 8 . l . 6 Transverse baffles. When transverse baffles are used in the feedwatcr heater for
type IV units to direct the flow of the hot fresh water across the tubes, the baffles shall be not
less than 1/8 inch thick A sufficient number of these baffles shall be increased in thickness to 1/4
inch to act as tube support plates. Holes for tubes in transverse baffles shall be drilled as specified
in 3.18.1.5 and shall have all roughness removed from the faces of the baffles at the edges of the
drilled holes,
3.l8.1.7 Desuperheater. If required by inlet steam conditions, an adequate desuperheater shall
be provided for the feedwater heater steam (type II). Desuperheater shall be supplied with a
strainer and isolation valve.
3.l8.l.8 Orifice plate An orifice plate with proper size orifice to limit the steam flow to the
salt water heater to that required for rated capacity shall be furnished (type II). Orifice plate shall
be provided with a tab for pulling and shall be stamped with the orifice size and manufacturer's
part number.
3.19 Distiller condenser for types I, III, and V.
3.19.1 Tubes. The distiller condenser shall be of the straight or U-bent tube, surface type with
cooling water in the tubes. It shall be a component of the distillation unit and may be built integral
with the last evaporator effect or as a separate unit. Sufficient surface shall be provided for
precooking the air ejector suction and may be provided for subcooling the distillate to specified
delivery temperature.
3.19.1.1 Tube surface. For types I, 111, and V distillation unit, the distiller condenser shall
have sufficient surface to condense the vapor from the last effect together with that flashed in the
flash chamber from the tube nest drains of the last effect (types I and III) at the requisite vacuum
when the distillation unit is operating in clean condition with initial sea water temperature of 85 `F.
3.19.2 Flash chamber. A flash chamber shall be provided for the distiller condenser of multiple
effects units. It shall receive the drains from the last evaporator effect tube nest through the drain
regulator, and shall be provided with an adequate vent to the distiller condenser shell. The distillate
from the distiller condenser shall combine with that portion of the last effect tube nest drains
which is not flashed and this final product of the distillation unit shall drain to the distillate pump
suction.
3.20 Distillate cooler for all types.
3.20.1 Cooler tube type. The distillate cooler shall be of the shell and straight or U-bent tube
type, arranged for circulation of the whole amount or part of circulating water required by the
distiller condenser (types I, III, and V) or the unit (types II and IV) through the tubes and for
circulation of the distillate drained from the distiller condenser flash chamber or the last stage
condenser across the tubes in the shell. If only part of the circulating water is used in the distillate
coder, the necessary bypass valves and piping shall be furnished with the cooler. The distillate
cooler shall not be completely bypassed.
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