belt drive, single stage, crosshead type, vertical, double acting, water
cooled, non-lubricated head type. Compressor shall be specially designed
for non-lubricated service, with a honed cylinder, piston rod packing,
piston rings, and piston wearing rings. Valve guide inserts and wear rings
shall be TFE. Valves shall be reversible and hardened, with stainless
steel seat plates for nonlubricated service.
Provide necessary sleeves,
baffles, and collars to prevent oil carryover.
Provide air-operated,
piston type, free air unloaders for capacity reduction and starting. Mount
inlet filter-silencer directly on the air inlet to the cylinder.
2.7.2.2
Aftercooler
Water cooled, with counter current flow, and installed directly between
each compressor cylinder and the air receiver. Design cooler to cool the
total output air flow of the compressor to within minus 9 degrees C 15
degrees F of the inlet cooling water temperature. Tube bundle shall be
removable for cleaning and inspection.
2.7.2.3
Air Receiver
Horizontal tank with a minimum volume of [_____] liters cubic feet.
Design unit for 1034 kPa (gage) 150 psig working pressure in accordance
with ASME BPVC SEC VIII receiver bearing the ASME Code Symbol stamp will be
accepted as meeting these requirements. Provide an automatic condensate
trap, safety valve, and outlet connection.
2.7.2.4
Electric Motor
Motor shall be [totally enclosed, fan controlled], [open drip proof],
[_____] kW hp, [_____] volt, [_____] phase, 60 Hz as specified under
paragraph entitled "Motors and Drives" in this section. Provide a
removable, totally enclosed belt guard.
2.7.2.5
Accessories
Factory assemble air compressors, drives, controls, air receiver,
aftercoolers, and miscellaneous hardware and mount on a steel supporting
base. Provide lifting lugs and tie down attachments. Air, water, and
condensate piping shall be provided and terminated at the edge of the
supporting base.
2.7.2.6
Controls
Provide controls and shutdowns necessary for automatic operation of the
compressor package. House controls in NEMA 12 control cabinet. Controls
shall include alternator control to switch compressors from lead to lag and
run both compressors when needed; 120 volt control transformer connected to
power circuit of compressor; air discharge pressure gage; selection
switches for constant speed for automatic dual control, along with
necessary time delay and control relays. Provide automatic
solenoid-operated cooling water valve in the cooling water line to the
compressors and aftercoolers. Factory wire control cabinet and mount as a
part of the package. Compressor safety controls and management panel shall
be provided as specified in paragraph entitled "Plant Air Compressor,"
located in this section.
2.7.3
Air Dryers
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SECTION 15502N
Page 82
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