shall be provided. Switches and lights shall have nameplate
identification. Paralleling of individual control power
transformers shall not be permitted. Panel shall be provided with
disconnect device . Disconnect shall be equipped with mechanical
door interlock preventing door opening with the disconnect in the
closed position. Fusing shall be cartridge type. Dual element,
current limiting, time delay safety switches shall be multiple
horsepower rated, heavy duty type. Magnetic motor starter for
each motor assembly shall be NEMA type, full voltage, non
reversing, overload protected for each phase, with auxiliary
contacts. Overload relay shall be trip-free, thermal bimetallic,
manual reset with trip heaters based on actual full load current
of motor. Spare NO and NC auxiliary contacts wired to the
primary fuse disconnect and secondary fusing shall be provided.
Factory mounted and wired control shall be provided, arranged to
receive a signal from the deaerator water level assembly. A panel
mounted Lead-Lag-Off-Continuous switch for feedwater pump shall be
provided.
3.
Sequence of Operation: From a cold start, when the plant master
controller indicates one boiler to start, the lead pump shall
start and operate continuously. When all boilers are off, all
pumps shall be off. Should there be a failure of any pump the
next pump in sequence shall operate automatically.
2.9
BOILER BOTTOM BLOWDOWN TANK
Blowdown tank shall be [_____] mm inches diameter by [_____] mm inches
high. Supports, associated accessories and appurtenances shall be as
specified and shown. Blowdown tank shall be of welded steel construction
built in accordance with ASME BPVC SEC VIII D1 and stamped for a 1.03 MPa
150 psig rating. Blowdown shall include a tangential inlet, size to match
boiler blowdown pipe, stainless steel striking plate at point of inlet
impingement, internal stainless steel flow restrictor plates, waterleg type
drain vent, gauge glass opening, inspection opening and clean-out
connections. Materials used in fabrication of boiler blowdown tank
equipment shall comply with ASME BPVC SEC II-C. Inspection openings on
tank shall be as required in paragraphs UG-45 and 46 of ASME BPVC SEC VIII
D1 and as shown. Connections shall be as shown. Interior surface
preparation shall be in accordance with SSPC SP 5 and the coating
manufacturer's recommendations. Interior shall be coated with a suitable
baked epoxy phenolic coating, minimum 0.13 mm 5 mil DFT. Exterior surface
preparation shall be in accordance with SSPC SP 6 and the coating
manufacturer's recommendations. Exterior shall be primed with a high heat
silicone acrylic primer, minimum 0.05 mm 2.0 mil DFT. The blowdown tank
shall be supplied with drain aftercooler and temperature regulating valve.
Aftercooler shall be provided with cold water inlet, flanged body for easy
removal, 6.35 mm 1/4 inch NPTF connection for temperature regulating valve
sensing bulb. Valve adjustable range shall be 43 to 65 degrees C 110 to
150 degrees F. A thermostatic regulating valve shall inject potable water
to maintain acceptable discharge temperature to the sewer.
2.10
BOILER SURFACE BLOWDOWN HEAT RECOVERY SYSTEM
2.10.1
General Requirements
Blowdown flush separator shall be [_____] mm inches in diameter by [_____]
SECTION 15561A
Page 87