ROOTS UNIVERSAL RAI Series, Установка, эксплуатация и обслуживание

Страница: 8 / 36

7
©2002 Dresser, Inc. all rights reserved.
ROOTS, RAM, URAI and WHISPAIR are trademarks of Dresser, Inc.
Dresser Design and Universal RAI are registered trademarks of Dresser, Inc.
Before operating a blower under power for the first
time, recheck the unit and the installation thoroughly
to reduce the likelihood of avoidable troubles. Use the
following procedure check list as a guide, but consider
any other special conditions in the installation.
❏
Be certain that no bolts, tools, rags, or debris have
been left in the blower air chamber or piping.
❏
If an outdoor intake without filter is used, be sure
the opening is located so it cannot pick up dirt and
is protected by a strong screen or grille. Use of the
temporary protective screen as described under
INSTALLATION is strongly recommended.
❏
Recheck blower leveling, drive alignment and
tightness of all mounting bolts if installation is not
recent. If belt drive is used, adjust belt tension
correctly.
❏
Turn drive shaft by hand to make sure impellers
still rotate without bumping or rubbing at any point.
❏
Make sure oil levels in the main oil sumps are
correct.
❏
Check lubrication of driver. If it is an electric motor,
be sure that power is available and that electrical
overload devices are installed and workable.
❏
Open the manual unloading valve in the discharge
air line. If a valve is in the inlet piping, be sure
it is open.
❏
Bump blower a few revolutions with driver to check
that direction of rotation agrees with arrow near
blower shaft, and that both coast freely to a stop.
After the preceding points are cleared, blower is
ready for trial operation under “no-load” conditions.
The following procedure is suggested to cover this
initial operation test period.
a. Start blower, let it accelerate to full speed, then
shut off. Listen for knocking sounds, both with
power on and as speed slows down.
b. Repeat above, but let blower run 2 or 3 minutes.
Check for noises, such as knocking sounds.
c. Operate blower for about 10 minutes unloaded.
Check oil levels. Observe cylinder and headplate
surfaces for development of hot spots such as
burned paint, indicating impeller rubs. Be aware
of any noticeable increase in vibration.
Assuming that all trials have been satisfactory, or that
necessary corrections have been made, the blower
should now have a final check run of at least one hour
under normal operating conditions. After blower is
restarted, gradually close the discharge unloading
valve to apply working pressure. At this point it is
recommended that a good pressure gauge or
manometer be connected into the discharge line if
not already provided, and that thermometers be in
both inlet and discharge lines. Readings from these
instruments will show whether pressure or temperature
ratings of the blower are being exceeded.
During the final run, check operating conditions
frequently and observe the oil levels at reasonable
intervals. If excessive noise or local heating develops,
shut down immediately and determine the cause. If
either pressure rise or temperature rise across the
blower exceeds the limit specified in this manual, shut
down and investigate conditions in the piping system.
Refer to the TROUBLESHOOTING CHECKLIST for
suggestions on various problems that may appear.
The blower should now be ready for continuous duty
operation at full load. During the first few days make
periodic checks to determine whether all conditions
remain steady, or at least acceptable. This may be
particularly important if the blower is supplying air to a
process system where conditions can vary. At the first
opportunity, stop the blower and clean the temporary
inlet protective screen. If no appreciable amount of
debris has collected, the screen may be removed.
See comments under INSTALLATION. At this same
time, verify leveling, coupling alignment or belt tension,
and mounting bolt tightness.
Should operating experience prove that blower capacity
is a little too high for the actual air requirements, a
small excess may be blown off continuously through
the manual unloading or vent valve. Never rely on the
pressure relief valve as an automatic vent. Such use
may cause the discharge pressure to become
excessive, and can also result in failure of the valve
itself. If blower capacity appears to be too low, refer to
the TROUBLESHOOTING CHECKLIST.
Vibration Assessment Criteria
With measurements taken at the bearing locations
on the housings, see chart below for an appropriate
assessment guide for rotary lobe blowers rigidly
mounted on stiff foundations.
In general, blower vibration levels should be monitored
on a regular basis and the vibration trend observed for
progressive or sudden change in level. If such a
change occurs, the cause should be determined
through spectral analysis.
As shown on the chart below, the level of all pass
vibration will determine the need to measure discrete
frequency vibration levels and the action required.
O
PERATION
All Pass Vibration Discrete Frequency Action
(in/sec) Vibration (in/sec)
0.45 or less N/R Approved
Greater than 0.45 0.45 or less @ Approved
but 1.0 or less any frequency
Greater than 0.45 @ ROOTS ™ Approval
any frequency Required
Greater than 1.0 Less than 1.0 ROOTS ™ Approval
Required
Greater than 1.0 ROOTS ™ Approval
Required