the feedwater from [_____] degrees C F to [_____] degrees C F at the flow
rates indicated. The heat exchanger shall consist of a steel shell and
heads with Type 304 stainless steel tubes arranged in a removable U-bend
bundle. The shell shall be constructed and tested in accordance with ASME
BPVC SEC VIII D1 for the specified boiler operating pressure. The
automatic proportioning valve shall be provided with a sensing orifice on
both the make-up and blowdown lines and shall be of the adjustable ratio
type in which the ratio of make-up to blowdown may be set anywhere within a
range of [30:1] [_____] to [4:1] [_____]. The automatic proportioning
control shall consist of two concentric tubes, the inner tube being of a
thermostatic design which acts directly against an adjustable seat in
response to the temperature differential between the blowdown in the inner
tube and the makeup water between the inner and outer tubes. Manual
apportioning valves shall have bronze bodies with stainless steel seats and
disks and shall be of the indicating type specifically designed for blowoff
service. The blowdown system shall be complete with strainers, stop
valves, [blowdown meters,] thermometers, and other accessories necessary to
form complete packaged units. [The blowdown control console shall include
illuminated sight flow indicators, automatic flushing and cooling valves,
and complete panelboard instrumentation, as well as a cabinet type
laboratory sink with drain board, back splash, hot and cold service water
faucets, [air cock,] and electrical outlet.]
2.11
FEEDWATER EQUIPMENT
2.11.1
Boiler Feed Pumps
Boiler feed pumps shall conform to MIL-P-17552 for motor driven, horizontal
split case or support head boiler feed pumps, except as otherwise specified
herein. Pumps may be of either the centrifugal or peripheral-turbine type
with alloy steel casing and shall be bronze or alloy steel fitted. For
centrifugal type pumps, by-pass orifice shall be provided, and for turbine
type pumps, pressure relief valves shall be provided. Packed stuffing
boxes or mechanical seals suitable for [121 degrees C250 degree F
operation] [the design conditions indicated] shall be provided. Pumps
shall be designed for the net positive suction head, discharge head, and
water temperature indicated. Pump casings should be rated at suction head
plus shutoff head at design temperature. [Capacity under the above
condition shall be not less than indicated.] [Capacity of each pump under
the above conditions shall be not less than the following percentage of
maximum total boiler capacity: centrifugal pumps, 125 percent; turbine
pumps, 150 percent.] Pump motors shall be [totally enclosed] [dripproof
with encapsulated windings].
2.11.2
Boiler Feed Tank
Feed tank and stand construction shall conform to MIL-P-17749 for
horizontal cylindrical stand mounted receivers, and shall be [hot dip
galvanized or cement lined] [epoxy coated] [[_____] coated]. Tanks shall
be provided with vents, gage glass, drain and overflow connections,
pressure gage, thermometer, [float operated make-up water feeder] [float
switch and make-up water solenoid valve] [and preheater assembly consisting
of corrosion resistant steam diffuser tube, steam pressure reducing valve,
strainer and thermostatic steam valve]. The boiler feed tank assembly
shall include strainer and pump control box. Tank capacity and connection
sizes shall be as indicated.
SECTION 15517N
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