Design unit for 1034 kPa (gage) 150 psig working pressure in accordance
with the ASME BPVC SEC VIII D1. A receiver bearing the ASME Code Symbol
stamp will be accepted as meeting these requirements. Provide an automatic
condensate trap, safety valve, and outlet connection.
2.7.2.3
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 total output air flow of compressor to within 9
degrees C 15 degrees F of inlet cooling water temperature. Tube bundle
shall be removable for cleaning and inspection.
2.7.2.4
Electric Motor
Each compressor shall be V-belt driven by a [_____] volt, [_____] phase, 60
Hz motor not less than [_____] kW hp as specified in paragraph entitled
"Motors and Drives." Provide a removable, totally enclosed belt guard.
2.7.2.5
Controls
Provide controls and shutdowns necessary for automatic operation of
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 needed; 120 volt control transformer; air discharge
pressure gage; selector switches for constant speed or 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 part of package.
2.7.2.6
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.
[2.7.2.7
Desiccant Air Dryer
**************************************************************************
NOTE: Choose this subparagraphs or the subparagraph
below, entitled "Refrigerated 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 [_____] standard L/s scfm of air to [_____]
degrees C F pressure dewpoint. Unit shall be field adjustable to maintain
pressure dewpoint of 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 water content to any preselected
level.
a.
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 unit
SECTION 15501N
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