14
For your nearest ROOTS Office, dial our Customer Service Hot Line 1 877 363 ROOTS (7668).
M
AINTENANCE
& R
EPLACEMENTS
: RAM
™
SERIES BLOWERS
A good program of consistent inspection and mainte-
nance is the most reliable method of minimizing repairs
to a blower. A simple record of services and dates will
help keep this work on a regular schedule. Basic
service needs are:
• Lubrication
• Checking for hot spots
• Checking for increases or changes in vibration
and noise
• Recording of operating pressures and temperatures
Above all, a blower must be operated within its
specified rating limits, to obtain satisfactory service life.
A newly installed blower should be checked often
during the first month of full-time operation. Attention
thereafter may be less frequent assuming satisfactory
performance. Lubrication is normally the most impor-
tant consideration and weekly checks of lubricant
levels in the gearbox and bearing reservoirs should
be customary. Complete oil change schedules are
discussed under LUBRICATION.
Driver lubrication practices should be in accordance
with the manufacturer’s instructions. If direct connected
to the blower through a lubricated type coupling, the
coupling should be checked and greased each time
blower oil is changed. This will help reduce wear and
prevent unnecessary vibration. In a belted drive sys-
tem, check belt tension periodically and inspect for
frayed or cracked belts.
In a new, and properly installed, unit there is no contact
between the two impellers, or between the impellers
and cylinder or headplates. Wear is confined to the
bearings (which support and locate the shafts) the oil
seals, and the timing gears. All are lubricated and wear
should be minimal if clean oil of the correct grade is
always used. Seals are subject to deterioration and
wear, and may require replacement at varying periods.
Piston ring seals (28) are designed to operate without
rubbing contact, once temperature and thermal growth
have stabilized. The stationary rings will rub the rotating
sleeve (38) briefly as a result of temperature cycles
that occur during the startup and shutdown of the unit.
The sleeves are hardened and the rings are coated
with dry lubricant that provides for temporary break in
wear. Replace piston ring seals if they become exces-
sively worn or inspection shows more than .010”
(.25mm) axial clearance between ring and groove.
Shaft bearings are designed for optimum life under
average conditions with proper lubrication and are
critical to the service life of the blower. Gradual bearing
wear may allow a shaft position to change slightly, until
rubbing develops between impeller and casing. This
will cause spot heating, which can be detected by
observing these surfaces. Sudden bearing failure is
usually more serious. Since the shaft and impeller are
no longer supported and properly located, extensive
general damage to the blower casing and gears is
likely to occur.
Oil seals should be considered expendable items, to
be replaced whenever drainage from the headplate
vent cavity becomes excessive or when the blower is
disassembled for any reason. Sealing effectiveness
can vary considerably from seal to seal and is also
affected to surprising degree by shaft finish under the
seal lip. Because of these normal variables, minor
seal leakage should not be considered as indicating
seal replacement.
Timing gear wear, when correct lubrication is main-
tained, should be negligible over a period of years.
Gear teeth are cut to provide the correct amount of
backlash, and gears correctly mounted on the shafts
will accommodate a normal amount of tooth wear
without permitting contact between lobes of the two
impellers. However, too high an oil level will cause
churning and excessive heating. This is indicated by
unusually high temperature at the bottom of the gear
housing. Consequent heating of the gears will result in
loss of tooth-clearance , backlash and rapid wear of the
gear teeth usually will develop. Continuation of this
tooth wear will eventually produce impeller contacts
(knocking), and from this point serious damage will be
unavoidable if blower operation is continued. A similar
situation can be produced suddenly by gear tooth
fracture, which is usually brought on by sustained
overloading or momentary shock loads.
Problems may also develop from causes other than
internal parts failure. Operating clearances within a
blower are only a few thousandths of an inch. This
makes it possible for impeller interferences or casing
rubs to result from shifts in the blower mounting, or
from changes in piping support. If this type of trouble
is experienced, and the blower is found to be clean, try
removing mounting strains. Loosen blower mounting
bolts and reset the leveling and drive alignment. Then
tighten mounting again, and make sure that all piping
meets blower connections accurately and squarely
Foreign materials sucked into the blower will also
cause trouble, which can only be cured by disconnect-
ing the piping and thoroughly cleaning the blower interior.
A wide range of causes & solutions for operating
troubles are covered in the TROUBLE SHOOTING
CHECKLIST. The remedies suggested should be
performed by qualified mechanics with a good
background, using procedures detailed in this manual.
Major repairs generally are to be considered beyond
the scope of maintenance, and should be referred
to ROOTS.
Warranty failures should not be repaired at all, unless
specific approval has been obtained through a Sales
Office or the factory before starting work. Unauthorized
disassembly within the warranty period will void the
warranty.
Содержание UNIVERSAL RAI Series
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