(2) Controls: Provide continuous supply of dry air by
automatically cycling operation of the desiccant beds. Dryer
shall be complete with panel mounted gages showing pressure in
each drying tower and spark suppressor to protect microswitch in
timer circuit. Total electrical power requirements shall not
exceed 75 watts at 110 Vac.
(3) Filters: Provide prefilter upstream of dryer to remove oil
vapor, liquid water, and solid particles. It shall have greater
than 99 percent efficiency in removing both 0.5 micron diameter
solid particles and 0.5 micron diameter oil aerosol. Filter shall
have replaceable oil absorbing filter element which turns red to
indicate saturation with oil and which shall be mounted in a
transparent cast methyl methacrylate tube for visibility and
inspection while on stream. Protect transparent acrylic tube by a
safety shield. Provide afterfilter for removal of solid particles
down to 5 microns size.]
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NOTE: Choose this item or item (a) above entitled
"Desiccant Air Dryer."
**************************************************************************
[b.
Refrigerated Air Dryer: Provide for systems not exposed to
freezing temperatures a compressed air dryer of self-contained
refrigerated type complete with heat exchanger, a commercial
quality refrigerated system, a moisture separator and condensate
trap, and internal wiring and piping. Install dryer between the
receiver and distribution line.
(1) Heat Exchanger: Provide air and refrigerant coils surrounded
by aluminum granules of sufficient mass to insure adequate cooling
capacity for varying air flow loads without causing excessive
refrigeration cycling. Provide an automatic control system, for
the heat exchanger with a sensing element located in the aluminum
granules, to shut down the refrigeration system on low or no-load
conditions. Provide means to determine exchanger temperature.
(2) Moisture Separator: Provide centrifuge type located within
the heat exchanger to provide for moisture separation at point of
minimum air temperature.
(3) Refrigeration Unit: Provide hermetically sealed type which
operates intermittently at all but maximum load conditions. The
unit shall be capable of drying [_____] L/s scfm of air to an
atmospheric dew point of not less than minus 23 degrees C 10
degrees F with entering air at 38 degrees C 100 degrees F,
saturated. The maximum operating pressure of the dryer shall be
[_____] kPa (gage) psig. House the entire unit in a steel
cabinet. Provide cabinet with access door and panel for easy
access to parts for maintenance and inspection.]
2.6.3
Pressure Reducing Regulator
Provide self-operating type designed for not less than a 1724 kPa (gage)
250 psig operating pressure, and a normal operating temperature range of
minus 29 degrees to plus 66 degrees C minus 20 degrees F to plus 150
degrees F. Regulator shall have an adjustable outlet pressure range not
less than 34 to 690 kPa (gage) 5 to 100 psig with not less than four
SECTION 15511N
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