] [ASTM A 240/A 240M] Type 316 stainless steel or ASTM A 242/A 242M Type 1
structural steel. Welding rods shall be specifically selected to be
compatible with the base metal and shall be submitted to the Contracting
Officer for approval. Provide protection of rods against moisture whether
for factory or field assembly.
2.2.2.1
Hopper Accessories
Provide at least one key interlocked hinged inspection cleanout and access
door on each hopper with gas tight seals. Each lock shall have a key
unique for this installation. Keys shall not be able to be removed from
the locks when access doors are opened. Access doors shall be a minimum
opening size of 460 by 600 mm 18 by 24 inches for rectangular openings and
600 mm 24 inches inside diameter for round openings. Hoppers with gas
baffles shall have access doors on both sides of the hopper. Provide each
hopper with provisions for attachment of vibrators. Hoppers shall have
adequate flexibility for vibrating. Provide each hopper with two 100 mm 4
inch poke holes with a tee wash connection and screwed caps. Position poke
holes to permit only downward thrusts into the hopper. A special
reinforced "pounding area" plate shall be provided on each hopper face for
external manual vibrating. Each pounding plate shall be 300 by 300 by 25 mm
12 by 12 by 1 inch thick ASTM A 36/A 36Mplate steel. Provide a work
platform with fixed stairs and railing and toe board to each pounding area
for units with pounding areas more than 1.50 meters five feet above ground.
Pounding plate shall not be insulated. Insulation shall be neatly
finished at this discontinuity. Provide a flanged fly ash outlet connection
on each hopper to accept the fly ash transportation system equipment.
Provide access hatch not less than 200 by 200 mm 8 by 8 inches for cleanout
within 200 mm 8 inches above flange on opposite sides. Bolt down type
hatches are acceptable for the cleanout hatch.
2.2.2.2
Hopper Vibrators
Provide each hopper with 2 vibrators set at the mid-height and on opposite
sides. Vibrator controls shall be interfaced with ash collection system to
provide vibrator operation only at the inception and during an evacuation
cycle. Operation shall be automatic. Provide manual override control for
hopper vibrators and evacuation system in the hopper area. Enclose
override control(s) in [a] case(s) to prevent accidental energization of
systems. Place a warning over the vibrator manual control with the
following inscription: "WARNING: VIBRATOR CONTROL. DO NOT ACTIVATE
UNLESS HOPPER EVACUATION SYSTEM IS OPERATING."
2.2.3
Multitube Collector Collecting and Outlet Tubes
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NOTE: Use these paragraphs for multitube collectors.
150 mm 6 inch diameter collecting tubes may cause a
plugging problem. Designer must investigate flue
gas particulate size, distribution and tendency of
particulates to adhere to each other for the
specific project before selecting diameter of
collector tubes.
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Fabricate multitube collector collecting tubes of material specified in
paragraph entitled "Materials." Material shall have a Brinell hardness of
not less than 400. Attach collecting tubes to tube sheet so that tubes may
be readily removable and replaceable. Collecting tube diameter shall be
SECTION 15861N
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