a.
Sealing strips, bolting materials and backing strips: ASTM B 443.
Provide both the upstream and downstream side of blade with
sealing strips around the periphery of the blade and on the
seating surfaces of the frame.
b.
Control interlocks: Provide control interlocks to prevent dampers
from simultaneously closing when the induced draft fan is
operating.
2.4.4.4
Seal Air Systems
Provide each guillotine damper with a seal air system, consisting of an
isolation damper or valve and a fan system, mounted onto the frame and
located within access for maintenance. Mount so that condensation between
the dampers flows into the ductwork. If installation on the damper frame
is not possible, provide a platform to support the equipment. Fan, at
design conditions, shall supply two times the guaranteed L/s cfmleakage
rate through the dampers and shall maintain not less than 747 Pa 3 inches WC
between the seal chamber and the flue gas. Control the seal chamber
pressure using a mild steel manual control damper or a minimum 55 percent
nickel, 20 percent chromium and 8 percent molybdenum gate or butterfly
valve. Valve shall operate on 552 to 862 kPa (gage) 80 to 125 psig
instrument air using a pneumatic piston operator. Should the air supply
fail, the piston actuator shall remain in the last position. Provide
instrumentation to monitor seal air system operation; tube and mount a
4-way dual-coil solenoid valve, with Class H coils rated for 120 VAC
service. Provide two dual-pole dual-throw limit switches, one to actuate
in the open position, one to actuate in the closed position, and house
within a NEMA ICS 6, Type 4 enclosure.
2.4.5
Test Ports
ASTM A 167, Type 316 stainless steel pipe, Schedule 40. Provide three 50 mm
2 inch pipe nipples with caps and rod-out on the topside of each
guillotine damper seal chamber and provide one 50 mm 2 inch port with
rod-out on the ductwork adjacent to each guillotine seal chamber, to attach
seal chamber pressure measurement tubing. Provide 150 mm 6 inch diameter
test ports on the horizontal side of the ductwork for air pollution
sampling; locate the test ports upstream baghouse and downstream baghouse.
Ports on ductwork shall extend 150 mm 6 inches beyond stiffeners to clear
insulation and lagging. Provide a screw plug for each test port. Coat
each plug with an antiseize lubricant appropriate for the design inlet
temperatures. Determine number, arrangement, and location of air pollution
sampling test ports using 40 CFR 60, EPA AP-42, Appendix A, Method 1.
Final number, location, and arrangement of test ports is subject to
Contracting Officer approval.
2.4.6
Mechanical Draft Equipment
Provide mechanical draft equipment complete with operators, accessories,
and field service.
2.5
HOPPERS
Provide insulated gas tight pyramidal hoppers as specified in paragraph
entitled "Design Criteria." Design to withstand vibration due to vibrators
and differential thermal expansion. Hoppers shall span no more than one
compartment. Weld hoppers to the baghouse compartments using continuous
fillet or complete penetration groove welds. Provide a minimum 300 mm 12
SECTION 15863N
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