2.6.2.3
Aftercooler
Aftercoolers shall be water cooled, with counter current flow, and shall be
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. The
tube bundle shall be removable for cleaning and inspection.
2.6.2.4
Electric Motor
Each compressor shall be V-belt driven by a [_____] volt, [_____] phase, 60
Hz motor not less than [_____] kW hp as specified under "Motors and Drives"
in this section. Provide a removable, totally enclosed belt guard.
2.6.2.5
Controls
Provide controls and shutdowns for automatic operation of the compressor
package. House controls in NEMA 12 control cabinet. Controls shall
include two, full voltage, automatic across-the-line starters; alternator
to switch compressors from lead to lag and to run both compressors when
required; 120 volt control transformer; 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.
2.6.2.6
Accessories
Factory assemble compressors, electric motors, controls, air receiver,
aftercoolers, and miscellaneous hardware and mount on steel supporting
base. Provide lifting lugs and tiedown attachments. Provide air, water,
and condensate piping and terminate them at the edge of the supporting
base. Lubricate inspection ports so that they can eaisly be removed for
visual inspections.
2.6.2.7
Air Dryers
**************************************************************************
NOTE: Choose this item or item (b) below entitled
"Refrigerated Air Dryer."
**************************************************************************
[a.
Desiccant Air Dryer: Provide for systems exposed to freezing
temperatures a compressed air desiccant dryer with noncorrosive
desiccant housed in twin pressure vessels, capable of drying
[_____] L/s scfm of air to [_____] degrees C Fpressure dewpoint.
Unit shall be field adjustable to maintain the pressure dewpoint
of the dried air at any preselected value below operating
temperature, to minus 40 degrees C F. As an integral part of the
unit provide an indicator showing the water content of the dry air
and a calibrated adjustment control to change the water content to
any preselected level.
(1) Design: Design unit for maximum temperature of not less than
49 degrees C 120 degrees F and maximum operating pressure of not
less than 1034 kPa (gage) 150 psig. Pressure drop through the
unit operating at full rated flow shall not exceed 28 kPa 4 psi.
SECTION 15511N
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