Milnor 6464TG1L, Руководство по установке, Страница: 49 / 85

Air and Ductwork Requirements for Milnor
®
Pass-through Dryers
PELLERIN MILNOR CORPORATION
negative air
—the condition in which air usage by equipment creates a negative air pressure in
the room where the equipment is located relative to outside air pressure and starves the
equipment of air
CAUTION 3 : Fire hazard
—Negative air will draw heat from a gas dryer into the room it is
in. Nearby objects, such as roof beams can become very hot.
• Provide inlet ductwork when negative air would otherwise occur.
If main air cannot be supplied from inside the room the dryers are in, use inlet ductwork to
connect the dryers to outside air. For gas dryers, use powered ventilation in the facility to
replenish the combustion air taken in by the dryers.
2.2.
Ductwork Durability
CAUTION 4 : Risk of mechanical failure
—The fluctuations in main air pressure that
occur during dryer operation will cause thin-gauge steel ductwork to quickly fail from metal
fatigue. Ducts with a rectangular cross-section can be damaged by these forces even when heavy
gauge material is used. Rectangular ductwork on the exhaust side of the dryer is likely to fail.
• Consult a ductwork design professional before you use rectangular duct.
The ductwork must be able to withstand the large flexing forces imposed on it by the internal air
pressure changes that occur during dryer operation. At minimum, straight sections fabricated
from galvanized sheet steel must have the following material thickness:
• Round duct - 20 gauge
• Rectangular duct - 16 gauge
It can be necessary to increase material thickness and use stiffeners for long duct lengths, large
duct sizes, transitions, and elbows.
Duct material must be able to withstand any corrosive forces imposed by the laundry environment.
Galvanized sheet steel is usually sufficient, but special conditions can occur.
2.3.
Ductwork Functionality
WARNING 5 : Fire and equipment malfunction hazards
—Incorrect ductwork design
can promote the buildup of flammable lint or cause flammable materials near hot ductwork to
ignite. It can also cause dryers to malfunction and greatly reduce productivity.
• Do not use any internal components in the ductwork (example: turning vanes).
• Obey codes that govern the clearances between hot ductwork and flammable construction
materials (example: roofing).
• Do not connect ducts from different dryers together if you can avoid it. See Section 2.3.1 .
• Do not use abrupt transitions or elbows with less than three segments. See Section 2.3.2 .
• Provide inspection covers as necessary to keep the entire ductwork clean.
2.3.1.
Multiple Dryers and Lint Collection
CAUTION 6 : Risk of equipment malfunction
—Dryers connected by common ductwork
are likely to malfunction due to the fluctuation in pressure drop felt by each dryer as a result of
the other dryers. This can occur even if the common duct is large enough to accommodate the
combined output of all connected dryers.
• Consult a ductwork design professional if you must use common ductwork.
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