shall be suitable for conveying lint and the temperatures encountered.
Equip the fan shaft with a heat slinger to dissipate heat buildup along the
shaft. Install an access (service) door to facilitate maintenance to these
fans.] Fan wheels over 900 mm 36 inches in diameter shall have overhung
pulleys and a bearing on each side of the wheel. Fan wheels 900 mm 36
inches or less in diameter may have one or more extra long bearings between
the fan wheel and the drive. Bearings shall be sleeve type, self-aligning
and self-oiling with oil reservoirs, or precision self-aligning roller or
ball-type with accessible grease fittings or permanently lubricated type.
Grease fittings shall be connected to tubing and serviceable from a single
accessible point. Bearing life shall be L50 rated at not less than 200,000
hours as defined by ABMA 9 and ABMA 11. Fan shafts shall be steel,
accurately finished, and shall be provided with key seats and keys for
impeller hubs and fan pulleys. Each fan outlet shall be of ample
proportions and shall be designed for the attachment of angles and bolts
for attaching flexible connections. [[Manually] [Automatically] operated
inlet vanes shall be provided on suction inlets. [Manually]
[Automatically] operated outlet dampers shall be provided.] Motors, unless
otherwise indicated, shall not exceed 1800 rpm and shall have [open]
[dripproof] [totally enclosed] [explosion-proof] enclosures. [Motor
starters shall be [manual] [magnetic] [across-the-line]
[reduced-voltage-start] type with [general-purpose] [weather-resistant]
[watertight] enclosure.] [Provide remote manual switch with pilot
indicating light where indicated.]
2.7.1.2
In-Line Centrifugal Fans
In-line fans shall have centrifugal backward inclined blades, stationary
discharge conversion vanes, internal and external belt guards, and
adjustable motor mounts. Mount fans in a welded tubular casing. Air shall
enter and leave the fan axially. Streamline inlets with conversion vanes
to eliminate turbulence and provide smooth discharge air flow. Enclose and
isolate fan bearings and drive shafts from the air stream. Fan bearings
shall be sealed against dust and dirt and shall be permanently lubricated,
and shall be precision, self aligning ball or roller type. Bearing life
shall be L50 rated at not less than 200,000 hours as defined by ABMA 9 and
ABMA 11. [Motors shall have [open] [dripproof] [totally enclosed]
[explosion-proof] enclosure.] [Motor starters shall be [manual] [magnetic]
across-the-line with [general-purpose] [weather-resistant]
[explosion-proof] enclosures.] [Provide remote manual switch with pilot
indicating light where indicated.]
2.7.1.3
Axial Flow Fans
Axial flow fans shall be complete with drive components and belt guard, and
shall have a steel housing, cast fan wheel, cast or welded steel diffusers,
fan shaft, bearings, and mounting frame as a factory-assembled unit. Fan
wheels shall have radially projecting blades of airfoil cross-section and
shall be dynamically balanced and keyed to the fan shaft. Enclose and
isolate fan bearings and drive shafts from the air stream. Fan bearings
shall be sealed against dust and dirt, shall be permanently lubricated or
with accessible grease fittings, and shall be precision self-aligning ball
or roller type. Bearing life shall be L50 rated at not less than 200,000
hours of operation as defined by ABMA 9 and ABMA 11. Provide fan inlets
with an aerodynamically shaped bell and an inlet cone. Install diffuser or
straightening vanes at the fan discharge to minimize turbulence and provide
smooth discharge air flow. Furnish fan unit with [inlet and outlet
flanges,] [inlet screen,] [duct equalizer section,] and [manual]
[automatic] operation adjustable inlet vanes. Unless otherwise indicated,
SECTION 15895
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