2.4.3.2
Constant Speed Control
Compressor shall operate continuously at constant speed. Provide means to
automatically load and unload compressor at preset minimum and maximum
pressure settings, respectively. Provide means for automatic release of
pressure within cylinders when the unit is operating without load. Also
provide means for manual or automatic unloading of cylinders during
starting of unit. [Equip compressor with a timed control to stop
compressor after a 10-minute unloaded period if air is not used.]
2.4.4
Intercoolers and Aftercoolers
Provide intercoolers between all intermediate stages of multi-stage
compressors and provide aftercoolers with compressors. Intercoolers for
air-cooled compressors shall be the tube-and-fin type. Intercoolers for
water-cooled compressors shall be the shell-and-tube type, except that
tube-and-fin type may be used when the intercooler is supported by the
compressor frame or attached to the compressor. Air or water cooled
intercoolers may be the integral cast type when compressor is 19 kW 25 hp
or less. Aftercoolers shall be of the water-cooled shell-and-tube type or
air-cooled tube-and-fin type. Water-cooled aftercoolers and intercoolers
shall be of sufficient capacity to cool the compressed air to within minus
9 degrees C and minus 7 degrees C 15 degrees F and 20 degrees F,
respectively, of the temperature of the water entering the coolers.
Air-cooled intercoolers and aftercoolers shall have sufficient capacity to
cool the compressed air to within minus 7 degrees C 20 degrees F of the
ambient temperature under the atmospheric conditions indicated. Provide
water-cooled intercoolers and aftercoolers with sight-flow indicator to
visually observe the flow of water to the cooler. The pressure drop of
compressed air through the cooler shall not exceed 7 kPa one psi. Provide
intercoolers and aftercoolers with a moisture separator and drain trap to
remove the condensed moisture and oil from the air leaving the cooler.
2.4.4.1
Shell-and-Tube
Floating-head type consisting of a removable and cleanable nest of
corrosion-resistant tubes within a steel shell. Air may pass either
through the tubes or the shell.
2.4.4.2
Tube-and-Fin
Copper, aluminum, copper-aluminum, or copper-alloy construction. Fins
shall be securely bonded to the tubing. Provide tube-and-fin coolers with
a fan for circulation of the cooling air. The fan shall be adequately
guarded for safety and be driven either from the compressor crankshaft or
by an independent electric motor.
2.4.5
Noise
84 dBA maximum sound level one meter from compressor unit.
2.5
MEDIUM PRESSURE Air receivers [and] [separators]
ASME BPVC SEC VIII D1, labeled and rated for [1896] [_____] kPa (gage)
[275] [_____] psig, equipped with required valves and trimmings, including
gage and automatic drain valve and ASME BPVC SEC VIII D1 and ASME BPVC SEC
IX pressure safety relief valve. Pressure as indicated. [Sandblast
exterior and interior to SSPC SP 10, near-white. Lining shall be a factory
applied 0.20 mm 8 mil minimum epoxy coating.] Exterior finish shall be
SECTION 15212N
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