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: [_____] mm inch 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
Heat Exchanger
Provide an ASME code stamped continuous blowoff heat exchanger designed and
constructed in accordance with ASME BPVC SEC VIII D1, to transfer heat from
the continuous blowoff water leaving continuous blowoff flash tank to
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 be
not 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 steam plant and related external auxiliary
equipment. Piping shall be in accordance with ASME B31.1 except as
modified below or indicated otherwise.
2.15.1
Expansion
Compute expansion of pipe with operating temperatures above minus 19
degrees C zero degrees F with minus 19 degrees C zero degrees F in lieu of
21 degrees C 70 degrees F specified in ASME B31.1.
2.15.2
Steam Heating and Distribution and Hot Water
Requirements of ASME B31.1 apply to building steam heating and steam
SECTION 15501N
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