over 5 1/2 kW 7 1/2 hp will be cost effective.
**************************************************************************
[Variable speed] electric motors [or turbines] direct connected to
respective pumps with a gear type, forged steel, flexible coupling.
Provide a shaft and coupling guard.
a.
Electric Motors: [Variable speed], [open dripproof], [totally
enclosed], [fan cooled], [_____] volt, three phase, 60 Hz of not
less than [_____] kW hp, as specified in paragraph[s] entitled
"Motors and Drives" [and "Variable Speed Control For Motors"].
[b. Steam Turbines: Single stage, rated at not less than [_____] kW hp,
with inlet steam pressure of [_____] kPa (gage) psig and [_____]
degrees C F and normal exhaust back pressure of 34 kPa (gage) 5
psig or a maximum back pressure of 103 kPa (gage) 15 psig. Water
rate at full load and normal steam conditions shall not exceed
[_____] kg per BkW per second pounds per BHP per hour. Provide a
stainless steel steam strainer, sentinel relief valve, sight oil
level indicator and one hand valve.
(1) Turbine Construction: Turbine casing split on the horizontal
centerline constructed of ASTM A 48M ASTM A 48cast iron, with a
design pressure rating of 1724 kPa (gage) at 232 degrees C 250
psig at 450 degrees F at inlet, and 379 kPa (gage) at 232 degrees C
55 psig at 450 degrees F at the outlet.
(2) Turbine Bearings and Shaft: Horizontal split, ring oiled,
sleeve type, water cooled. Shaft shall be stainless steel or
chrome plated under the packing glands. Shaft seals shall be
segmented carbon rings with springs and stops.
(3) Speed Governor: Variable speed oil relay, NEMA SM 23, Class
D governor for speed control and pneumatic operator to maintain an
adjustable, preset pump discharge header pressure by variation of
turbine speed. Input to the operator shall be a 20 to 103 kPa
(gage) 3 to 15 psig pneumatic signal. Provide an
electro-pneumatic transducer to accept the 4 to 20 mA signal from
the control acquisition system.
(4) Emergency Overspeed Governor: Completely independent of the
speed governor and shall operate a separate trip valve.
(5) Insulation: Turbine shall be insulated and lagged by the
manufacturer as specified in Section 15080 THERMAL INSULATION FOR
MECHANICAL SYSTEMS.]
2.14.3.4
Minimum Flow Protection for Boiler Feed Water Pumps
a.
Automatic Flow Control Valve: Provide with each pump an automatic
bypass valve. Valve shall automatically program recirculation
flow, detection of low flow, cycling of control valve and pressure
letdown for high pressure boiler feedwater return to the feedwater
heater. Bypass valve shall be cast steel with stainless steel
internals, and shall have a rating of not less than 2068 kPa
(gage) at 204 degrees C 300 psig at 400 degrees F. Valve shall
have a line size body with a 25 mm one inchrecirculation
connection.
SECTION 15501N
Page 127
Previous Page
