1144. Shaft main bearings shall be either sleeve-design type with leaded
bronze or steel-backed babbit; or frictionless bearing design, ball or
roller type. Housings and covers shall be high-grade, cast iron or
aluminum pressure castings. Lubrication systems shall lubricate rotors,
bearings, shaft seal as well as rotor sealing and cooling. Provide an oil
safety cutout interlocked with the compressor starter to allow compressor
to operate only when oil system is operational. Provide for lubrication of
bearings and shaft seals on shutdown with or without electrical power
supply. Compressors shall operate stably and for indefinite periods of
time at any stage of capacity reduction from 100 to 10 percent of full load
capacity.
2.1.1.3
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NOTE: The selection of the double-tube bundle is a
design function where a steady demand exists for low
grade rejected heat. Where this demand does not
exist or where the heat recovery cannot be
justified, the single-tube bundle should be used.
When marine water boxes are requested by the
activity, use the second bracketed sentence and
delete the first bracketed sentence. If not
requested, use the first bracketed sentence and
delete the second bracketed sentence.
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[Shell-and-tube construction shall permit tubes to be cleaned from each end
by removing water box cover plates or head and minimum amount of water
piping.] [Shell-and-tube construction with water boxes having side mounted
piping connections and cover plates to permit tubes to be cleaned from each
end without removing connected piping.] Refrigerant side design pressure
shall comply with ASHRAE 15. Water side design pressure shall not be less
than 1034 kPa (gage) 150 psig. Tubes shall be fabricated of seamless
copper tubing, with plan or integral fins and shall be individually
replaceable and rolled or brazed into copper or steel tube sheets. Base
performance on a water velocity not less than 0.91 meter per second (m/s) 3
feet per second (fps) nor more than 3.66 m/s 12 fps and a fouling factor of
0.00075. Condensers shall be [single] [double]-tube bundle type.
2.1.1.4
Liquid Coolers (Evaporators)
Removable copper tube, bundle type constructed of seamless copper tubing
rolled or brazed into copper or steel tube sheets with baffles and tube
supports of copper; or liquid cooler shall be fabricated of seamless copper
tubing, plain or with integral fins, individually replaceable and rolled or
brazed into copper or steel tube sheets with tube supports of copper or
steel plate. Refrigerant side design pressure shall comply with ASHRAE 15.
Water side design pressure shall not be less than 1034 kPa (gage) 150 psig.
Liquid cooler feed control shall feed liquid cooler at all levels of
capacity from 100 percent down to minimum required operating level. Base
performance on a water side velocity not less than 0.91 m/s 3 fps nor more
than 3.66 m/s 12 fps, and fouling factor of 0.00025.
2.1.1.5
Purge Systems
If chiller operates at refrigerant pressures below 101.34 kpa(gage) 14.7
psig, provide a purge system and connect to main refrigeration system.
Purge systems shall automatically remove air, water vapor, and
SECTION 15601N
Page 13
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