pressurized type, tungsten carbide and carbon sealing faces especially
designed for high temperature, high pressure boiler feed pump service.
Mechanical seals shall be provided with pumping rings. Complete field
flush piping from each mechanical seal to its respective seal cooler shall
be provided with a temperature alarm thermometer, adjustment for silencing,
range of 10 to 204 degrees C 50 to 400 degrees F with contacts suitable for
100 milliamperes at 125 V dc, closing on rise of temperature.]
2.7.2.6
Shaft Coupling
[Shaft coupling between vertical pump and drive shall be direct coupled
type.] [Horizontal pump shall be direct connected to its motor by means of
a spacer disc type coupling. Spacer piece provided between motor and pump
shall facilitate removal of coupling flanges and mechanical seals without
disturbing the pump or motor hold-down bolts. Disc coupling shall be
limited and float. Disc shall be stainless steel. Suitable coupling
guards shall be furnished.]
2.7.2.7
Special Tools
Complete set of special tools shall be furnished as required for assembly,
disassembly or maintenance of pumps.
2.7.2.8
Pump Characteristics
a.
Pump discharge head shall be such that the maximum discharge head
occurs at shutoff and continually decreases as pump delivery
increases. Head capacity characteristics shall permit stable
operation when pump is operating alone or in parallel with another
pump.
b.
Pump shall have shutoff head of not greater than 150 percent and
not less than 115 percent of design head. Design point capacity
on the selected pump curve shall be within 25 percent of the
capacity at the best efficiency point for the impeller selected.
Minimum flow required for continuous pump operation shall not be
greater than 30 percent of the specified design flow for each pump.
c.
Pump shall have efficiency of 60 percent or greater at rated
capacity.
2.7.2.9
Horizontal Pump Accessory Equipment
Following shall be provided as package from pump manufacturer:
a.
Pump and drive, mounted on a suitable, full length baseplate.
b.
Suitable vent valves for the pump.
c.
Stainless steel orifice plate for minimum flow across the pump.
d.
Standard accessories and integral piping required for complete
unit.
e.
One flanged end suction tee type strainer of corrosion resistant
materials, of size compatible with suction piping. Tee type
strainer shall have fine mesh screen fitted over it for use during
startup period. Fine mesh screen shall be removed after
condensate system is clean.
SECTION 15561A
Page 78
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