lower head of tank will be not less than 457 mm 18 inches above
floor.
b.
Automatic control system: Control level in the flash tank, by
modulating a valve in the water outlet line.
(1) Level controller: External cage type air operated level
controller, complete with 40 mm 1 1/2 inch screwed connection, 350
mm 14 inch stainless steel float and Class 125 cast iron body.
Controller shall be direct acting with 20 to 103 kPa (gage) 3 to
15 psig range with proportional band. Locate controller to
maintain an operating level at center line of storage tank.
Provide level controller with air pressure reducing valve, filter,
gages and isolating valves for float cage. Provide unions on each
side of float cage.
(2) Outlet water valve: [_____] air operated control valve with
a capacity to pass [_____] L/s gpm at a pressure drop of [_____]
kPa (gage) psig. Cv shall not be less than [_____] at 100 percent
open. Valve shall be Class [_____], flanged, iron or semi-steel
body with stainless steel internals. Valve shall have equal
percentage flow characteristics with a full size port. Provide an
air lock mounted on valve diaphragm and piped to hold valve in
last position on air failure.
2.14.11.3
Sample Cooler
Water cooled shell and tube type with valves and accessories required to
safely withdraw a water sample from the boiler drum. Provide drain under
sampling valve terminating with a 20 mm 3/4 inch splash proof funnel, 229 mm
9 inches below outlet of valve.
2.14.11.4
Provide an ASME code stamp continuous blowoff heat exchanger designed and
constructed in accordance with the ASME BPVC SEC VIII, to transfer heat
from the continuous blowoff water leaving the existing continuous blowoff
flash tank to the treated makeup water entering the feedwater heater. Heat
exchanger shall be a bare tube, helical coiled bundle, installed in a one
piece casing with removable front plate. Bundle shall be removable. Tube
diameter shall not be less than 20 mm 3/4 inch. Tubes shall be ASTM B
111/B 111M copper alloy, with cast iron shell. Design tube side for not
less than [_____] kpa (gage) psig pressure at [_____] degrees C F. Design
shell side for not less than [_____] kpa (gage) psig pressure at [_____]
degrees C F.
2.15
PIPING
Piping work shall include the provision, of piping systems, including
valving and specialty items, for the steam plant and related external
a.
Piping materials, design, and fabrication shall be in accordance
with ASME B31.1 except as modified otherwise below or indicated
otherwise.
b.
Compute expansion of pipe with operating temperatures above minus
19 degrees C zero degrees F in lieu of 21 degrees C 70 degrees F
specified in ASME B31.1.
SECTION 15502N
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