[standard factory finish] [two coats of rust inhibitor primer and one coat
epoxy enamel].
2.6
MEDIUM PRESSURE COMPRESSED AIR DRYERS
**************************************************************************
NOTE: Make changes for medium pressure systems and
insert the desired operating pressure. Normally
used for under 944 scms 2000 scfm capacity systems.
CAUTION: ASSURE CORRECT SYSTEM PRESSURE IS
SPECIFIED.
**************************************************************************
Provide medium pressure compressed air dryers of the mechanical
refrigeration type, equipped with an automatic temperature shutdown switch
to prevent freezing, a regenerative air to air exchanger (in capacity sizes
above 5 to 28 scms 10 or 60 scfm as standard with the manufacturer), and a
main compressed air cooling exchanger. Refrigeration system shall cool
compressed air to dry the air. Dryer shall have no internal traps or
filters and shall have pressure drop not greater than [21 kPa] [_____ kPa]
[3 psi] [_____ psi] [indicated]. Air shall leave the dryer at a
temperature of [_____] degrees C F and dew point of [_____] degrees C F,
based on an inlet temperature of [38] [_____] degrees C [100] [_____]
degrees F. Provide internal tubing, wiring, and piping complete, such that
only connections to air inlet and outlet, to refrigerant compressor
contactor, and to condensate drain are necessary.
2.6.1
Air Circuit
a.
Regenerative heat exchanger: Inlet compressed air to outlet
compressed air heat exchanger (in capacity sizes above 5 to 28 scms
10 or 60 scfm as standard with the manufacturer) designed to
reduce cooling load at design conditions minus 7 degrees C 20
degrees F by inlet air precooling.
b.
Main heat exchanger: Single-pass, with air in the tubes, heat
sink, direct expansion, or flooded cooler type.
c.
Separator: Fabricated in accordance with ASME B31.1; code stamp
not required; moisture separator low velocity type incorporating
change of air flow direction to prevent moisture carryover.
d.
Dryer operating pressure:
[1896] [_____] kPa (gage) [275] [_____]
psig working pressure.
e.
Drain line: Provide with exterior mounted condensate trap to
facilitate servicing.
2.6.2
Refrigeration System
a.
Refrigeration compressor: ARI 520. Hermetic, semi-hermetic, or
open reciprocating type equipped with automatic start-stop or
unloading capacity control; standard components include inherent
motor protection, crankcase oil strainer, and suction screen.
Refrigerant shall be R-22.
b.
Dryer controls: Capable of automatic 0 to 100 percent capacity
control. Refrigeration controls shall maintain pressure dew point
within the specified range without freezing of condensate.
SECTION 15212N
Page 23
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