the combs fully submerged.
c. Normal and maximum liquid levels, including
flooding level for submersible drive.
d. Allowable head loss at maximum flow. Head loss
should not be set too low for it could exclude
rotating type comminutors.
e. Whether comminutor has free discharge or
controlled discharge.
f. Whether location requires explosion-proof
equipment.
g.
Electrical power characteristics.
h. Type of drive mounting and elevations pertinent
thereto.
i. Channel design, size and type, should be
conducted in manner that optimizes channel width and
allows for maximum competition among comminutor
suppliers. If the channel width is designed too
narrow it could exclude rotating type comminutors.
j. Each comminutor device should have a by-pass for
maintenance and repair purposes.
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Comminutor shall be capable of passing a minimum flow of [_____] cubic
meters/second million gallons per day (mgd), an average flow of [_____]
cubic meters/second mgd, and a maximum flow of [_____] cubic meters/second
mgd. Head loss at maximum flow shall not exceed [_____] mm inches of
water. Comminutor shall be designed for [free] [controlled] discharge.
[Downstream submergence shall be [_____] mm inches at maximum flow for
controlled discharge units.] Comminutor shall be capable of operating
satisfactorily at zero flow.
2.9
GEAR MOTOR
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NOTE: Totally enclosed motors should be used except
in locations where explosive-proof equipment is
required.
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Electric motor shall be constant speed, [totally enclosed] [totally
enclosed fan cooled] [explosion-proof], capable of operating in air,
partially or completely submerged. Motors shall be UL listed for Class I,
Div I, Group D service, horizontal or vertical type, suitable for outdoor
use and conforming to NEMA MG 1. The unit shall be capable of withstanding
any loadings produced by the thrust, out-of-balance, and vibrating forces
resulting from operating conditions. Gears shall be wrought or alloy steel
except that worm gears shall be bronze. Flame hardened gears will not be
acceptable. Housing shall be close-grained cast iron, fabricated steel, or
aluminum alloy.
SECTION 11331
Page 9
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