Controls shall include such devices as capillary tube, expansion
valve, suction pressure regulator, thermostat, or other approved
devices as standard with the manufacturer. Dryer shall have
automatic shutdown switch sensor located at point of lowest
temperature to prevent freezing.
c.
Refrigerant dryer and suction line strainer.
d.
Air-cooled condenser, with condenser fan and motor.
2.6.3
Instrumentation and Control
Include control panel in dryer cabinet containing:
a.
Indicators for the following services: Inlet air pressure gage,
discharge air pressure gage, inlet air temperature gage, main
exchanger temperature gage, refrigeration compressor suction
pressure gage, refrigeration compressor discharge pressure gage,
green "Power On" light, power interruption light, and high
temperature light.
b.
Electrical relays: Locate in an enclosed portion of the panel,
accessible for ease of servicing.
c.
Controls and interlocks: To maintain required compressed air dew
point and to cycle air-cooled condenser with refrigeration
compressor [while maintaining head pressure control with low
ambient temperature].
2.7
MEDIUM PRESSURE COMPRESSED AIR DRYER (CHILLED WATER TYPE)
**************************************************************************
NOTE: Edit for medium pressure systems and insert
the operating pressure. Chilled water air dryers
are usually provided for 944 scms 2000 scfm and
larger capacities. CAUTION: Specify correct system
pressure. If specification is edited to use a dryer
with direct heat exchange between air and
refrigerant, assure that air is not used for
breathing since refrigerant leakage into the
compressed air may be hazardous to personnel;
warning signs may be required.
**************************************************************************
Provide medium pressure compressed air dryer of the mechanical refrigerator
type, with closed chilled water system, regenerative air to air exchanger,
and main compressed air to water heat exchanger. Refrigeration system
shall produce chilled water which, in turn, circulates through air-water
exchanger to dry the air. Provide internal tubing, wiring and piping
complete, such that only connections to air inlet and outlet, to pump
contactor, to refrigerant compressor contactor, to condensate drain, and to
air cooled condenser need be provided. Dryer shall be suitable for a
compressed air operating pressure of [1896] [_____] kPa (gage) [275]
[_____] psig, with air leaving temperature of [_____] degrees C F and dew
point of [_____] degrees C F at rated pressure.
2.7.1
Air Circuit
a.
Regenerative heat exchanger:
Air to air exchanger, with inlet air
SECTION 15212N
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