Howden Roots Tri-RAM 416, Roots Tri-RAM 413, Roots Tri-RAM 722, Roots Tri-RAM 728, Roots Tri-RAM832 Installation, Operation & Maintenance Manual
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Roots
TM
Tri-RAM
TM
Tri-lobe
Blowers
Installation Operation & Maintenance Manual
Contents
Information Summary ...............................................................2
Safety Precautions
Operating Limitations
Installation
........................................................................... 4 - 6
Lubrication
Operation
..................................................................................8
....................................................................3
................................................................3
................................................................................7
Troubleshooting
Inspection & Maintenance
Figures
............................................................................ 11 - 12
Tables
.....................................................................................13
Parts List
.................................................................... 14, 17, 19
Assembly Drawings
Do these things to get the most from your Roots Blower
........................................................................9
......................................................10
...........................................15 - 16, 18, 20
• Check shipment for damage. If found, file claim with
carrier and notify Howden.
• Unpack shipment carefully, and check contents against
Packing List. Notify Howden if a shortage appears.
• Store in a clean, dry location until ready for installation.
Lift by methods discussed under INSTALLATION to
avoid straining or distorting the equipment. Keep covers
on all openings. Protect against weather and corrosion
if outdoor storage is necessary.
• Read OPERATING LIMITATIONS and INSTALLATION
sections in this manual and plan the complete
installation.
• Provide for adequate safeguards against accidents
to persons working on or near the equipment
during both installation and operation. See SAFETY
PRECAUTIONS.
• Install all equipment correctly. Foundation design
must be adequate and piping carefully done. Use
recommended accessories for operating protection.
• Make sure both driving and driven equipment is
correctly lubricated before start-up. See LUBRICATION.
• In event of trouble during installation or operation, do
not attempt repairs of Roots furnished equipment.
Notify Roots, giving all nameplate information plus an
outline of operating conditions and a description of the
trouble. Unauthorized attempts at equipment repair
may void Roots warranty.
• Units out of warranty may be repaired or adjusted by
the owner. Good inspection and maintenance practices
should reduce the need for repairs.
NOTE: Information in this manual is correct as of the date
of publication. Howden reserves the right to make design or
material changes without notice, and without obligation to make
similar changes on equipment of prior manufacture.
For your nearest Howden Office, dial our Customer Service
Hot Line toll free in the U.S.; 1 877 363 7668 or direct +1
Roots products are sold subject to the current General Terms of Sale, ES104 and Warranty Policy WP-5020.
Copies are available upon request.
2
GEA19684 ISRB_2008 rev._11.15
Safety Precautions
It is important that all personnel observe safety precautions
to minimize the chances of injury. Among many considerations, the following should be particularly noted:
• Blower casing and associated piping or accessories
may become hot enough to cause major skin burns on
contact.
• Internal and external rotating parts of the blower and
driving equipment can produce serious physical injuries.
Do not reach into any opening in the blower while it is
operating, or while subject to accidental starting. Protect external moving parts with adequate guards.
• Disconnect power before doing any work, and avoid
bypassing or rendering inoperative any safety or protective devices.
• If blower is operated with piping disconnected, place a
strong coarse screen over the inlet and avoid standing
in the discharge air stream.
Operating Limitations
A Roots blower or exhauster must be operated within
certain approved limiting conditions to enable continued
satisfactory performance. Warranty is contingent on such
operation.
Maximum limits for pressure, temperature and speed are
specified in TABLE 1, page 13 for various models & sizes
of blowers & exhausters. These limits apply to all units
of normal construction, when operated under standard
atmospheric conditions. Be sure to arrange connections or
taps for instruments such as thermometers and pressure or
vacuum gauges at or near the inlet and discharge connections of the unit. These, along with a tachometer, will enable
periodic checks of operating conditions.
PRESSURE – The pressure rise, between inlet and discharge, must not exceed the figure listed for the specific unit
frame size concerned. Also, in any system where the unit
inlet is at a positive pressure above atmosphere a maximum
case rating of 25 PSI gauge (1725 mbar) should not be
exceeded without first consulting Roots. Never should the
maximum allowable differential pressure be exceeded.
On vacuum service, with the discharge to atmospheric pressure, the inlet suction or vacuum must not be greater than
values listed for the specific frame size.
TEMPERATURE – Blower & exhauster frame sizes are approved only for installations where the following temperature
limitations can be maintained in service:
CAUTION: Never cover the blower inlet with your hand
or other part of body.
• Stay clear of inlet and discharge openings.
• Stay clear of the blast from pressure relief valves and
the suction area of vacuum relief valves.
• Use proper care and good procedures in handling, lifting, installing, operating and maintaining the equipment.
• Casing pressure must not exceed 25 PSI (1725 mbar)
gauge. Do not pressurize vented cavities from an external source, nor restrict the vents without first consulting
Roots.
• Do not use air blowers on explosive or hazardous
gases.
• Other potential hazards to safety may also be associated with operation of this equipment. All personnel working in or passing through the area should be trained to
exercise adequate general safety precautions.
• Measured temperature rise must not exceed listed values when the inlet is at ambient temperature. Ambient
is considered as the general temperature of the space
around the unit. This is not outdoor temperature unless
the unit is installed outdoors.
• If inlet temperature is higher than ambient, the listed
allowable temperature rise values must be reduced by
2/3 of the difference between the actual measured inlet
temperature and the ambient temperature.
• The average of the inlet and discharge temperature
must not exceed 250°F. (121°C).
• The ambient temperature of the space the blower/
motor is installed in should not be higher than 120°F
(48.8°C).
SPEED – These blowers & exhausters may be operated
at speeds up to the maximum listed for the various frame
sizes. They may be direct coupled to suitable constant
speed drivers if pressure/temperature conditions are also
within limits. At low speeds, excessive temperature rise may
be a limiting factor.
Special Note: The listed maximum allowable temperature
rise for any particular blower & exhauster may occur well
before its maximum pressure or vacuum rating is reached.
This may occur at high altitude, low vacuum or at very low
speed. The units’ operating limit is always determined by the
maximum rating reached first. It can be any one of the three:
Pressure, Temperature or Speed.
GEA19684 ISRB_2008 rev._11.15
3
Installation
Roots blowers & exhausters are treated after factory assembly
to protect against normal atmospheric corrosion. The maximum period of internal protection is considered to be one year
under average conditions, if shipping plugs & seals are not
removed. Protection against chemical or salt water atmosphere
is not provided. Avoid opening the unit until ready to start
installation, as corrosion protection will be quickly lost due to
evaporation.
If there is to be an extended period between installation and
start up, the following steps should be taken to ensure corrosion protection.
• Coat internals of cylinder, gearbox and drive end
bearing reservoir with Nox-Rust VCI-10 or equivalent.
Repeat once a year or as conditions may require. NoxRust VCI-10 is petroleum soluble and does not have to
be removed before lubricating. It may be obtained from
Daubert Chemical Co., 2000 Spring Rd., Oak Brook, Ill.
60521.
• Paint shaft extension, inlet and discharge flanges, and
all other exposed surfaces with Nox-Rust X-110 or
equivalent.
• Seal inlet, discharge, and vent openings. It is not
recommended that the unit be set in place, piped to
the system, and allowed to remain idle for extended
periods. If any part is left open to the atmosphere, the
Nox-Rust VCI-10 vapor will escape and lose its effectiveness.
• Protect units from excessive vibration during storage.
• Rotate shaft three or four revolutions every two weeks.
• Prior to start up, remove flange covers on both inlet and
discharge and inspect internals to insure absence of
rust. Check all internal clearances. Also, at this time, remove gearbox and drive end bearing cover and inspect
gear teeth and bearings for rust.
Because of the completely enclosed unit design, location of
the installation is generally not a critical matter. A clean, dry
and protected indoor location is preferred. However, an outdoor location will normally give satisfactory service. Important
requirements are that the correct grade of lubricating oil be
provided for expected operating temperatures, and that the
unit be located so that routine checking and servicing can be
performed conveniently. Proper care in locating driver and
accessory equipment must also be considered.
Supervision of the installation by a Roots Service Engineer is
not usually required for these units. Workmen with experience
in installing light to medium weight machinery should be able
to produce satisfactory results. Handling of the equipment
needs to be accomplished with care, and in compliance with
safe practices. Unit mounting must be solid, without strain or
twist, and air piping must be clean, accurately aligned and
properly connected.
Bare-shaft Units: Two methods are used to handle a unit
without base. One is to use lifting lugs bolted into the top of
the unit headplates. Test them first for tightness and fractures
by tapping with a hammer. In lifting, keep the direction of
cable pull on these bolts as nearly vertical as possible. If lifting
lugs are not available, lifting slings may be passed under the
cylinder adjacent to the headplates. Either method prevents
strain on the extended drive shaft.
Packaged Units: When the unit is furnished mounted on a
baseplate, with or without a driver, use of lifting slings passing
under the base flanges is required. Arrange these slings so
that no strains are placed on the unit casing or mounting feet,
or on any mounted accessory equipment. DO NOT use the
lifting lugs in the top of the unit headplates.
Before starting the installation, remove plugs, covers or seals
from unit inlet and discharge connections and inspect the interior completely for foreign material. If cleaning is required, finish
by washing the cylinder, headplates and impeller thoroughly
with a petroleum solvent. Turn the drive shaft by hand to
make sure that the impellers turn freely at all points. Anti-rust
compound on the connection flanges and drive shaft extension may also be removed at this time with the same solvent.
Cover the flanges until ready to connect piping.
Mounting
Care will pay dividends when arranging the unit mounting. This
is especially true when the unit is a “bare-shaft” unit furnished
without a baseplate. The convenient procedure may be to mount
such a unit directly on a floor or small concrete pad, but this generally produces the least satisfactory results. It definitely causes
the most problems in leveling and alignment and may result in a
“Soft Foot” condition. Correct soft foot before operation to avoid
unnecessary loading on the casing and bearings. Direct use of
building structural framing members is not recommended.
For blowers without a base, it is recommended that a well
anchored and carefully leveled steel or cast iron mounting
plate be provided. The plate should be at least 1 inch (25 mm)
thick, with its top surface machined flat, and large enough to
provide leveling areas at one side and one end after the unit is
mounted. It should have properly sized studs or tapped holes
located to match the unit foot drilling. Proper use of a high
quality machinist’s level is necessary for adequate installation.
With the mounting plate in place and leveled, set the unit
on it without bolting and check for rocking. If it is not solid,
determine the total thickness of shims required under one foot
to stop rocking. Place half of this under each of the diagonallyopposite short feet, and tighten the mounting studs or screws.
Rotate the drive shaft to make sure the impellers turn freely.
If the unit is to be direct coupled to a driving motor, consider
the height of the motor shaft and the necessity for it to be
aligned very accurately with the unit shaft. Best unit arrangement is directly bolted to the mounting plate while the driver
is on shims of at least 1/8 inch (3mm) thickness. This allows
adjustment of motor position in final shaft alignment by varying
the shim thickness.
Aligning
When unit and driver are factory mounted on a common
baseplate, the assembly will have been properly aligned and is to
be treated as a unit for leveling purposes. Satisfactory installation can be obtained by setting the baseplate on a concrete
slab that is rigid and free of vibration, and leveling the top of the
base carefully in two directions so that it is free of twist. The slab
must be provided with suitable anchor bolts. The use of grouting
under and partly inside the leveled and shimmed base is recommended.
4
GEA19684 ISRB_2008 rev._11.15
It is possible for a base-mounted assembly to become
twisted during shipment, thus disturbing the original alignment. For this reason, make the following checks after the
base has been leveled and bolted down. Disconnect the drive
and rotate the unit shaft by hand. It should turn freely at all
points. Loosen the unit foot hold-down screws and determine
whether all feet are evenly in contact with the base. If not,
insert shims as required and again check for free impeller rotation. Finally, if unit is direct coupled to the driver, check shaft
and coupling alignment carefully and make any necessary
corrections.
In planning the installation, and before setting the unit,
consider how piping arrangements are dictated by the unit
design and assembly. Drive shaft rotation must be established
accordingly and is indicated by an arrow near the shaft.
Typical arrangement on vertical units has the drive shaft at the
top with counterclockwise rotation and discharge to the left.
Horizontal units are typically arranged with the drive shaft at
the left with counterclockwise rotation and discharge down.
See Figure 4 for other various unit arrangements and possible
conversions.
When a unit is DIRECT COUPLED to its driver, the driver
RPM must be selected or governed so as not to exceed the
maximum speed rating of the unit. Refer to Table 1, page 13
for allowable speeds of various unit sizes.
A flexible type coupling should always be used to connect the
driver and unit shafts.
When direct coupling a motor or engine to a blower you must
ensure there is sufficient gap between the coupling halves and
the element to prevent thrust loading the blower bearings.
When a motor, engine or blower is operated the shafts may
expand axially. If the coupling is installed in such a manner
that there is not enough room for expansion the blower shaft
can be forced back into the blower and cause the impeller
to contact the gear end headplate resulting in damage to the
blower. The two shafts must be in as near perfect alignment
in all directions as possible, and the gap must be established
with the motor armature on its electrical center if end-play exists. Coupling manufacturer’s recommendations for maximum
misalignment, although acceptable for the coupling, are
normally too large to achieve smooth operation and maximum
life of the blower.
The following requirements of a good installation are
recommended. When selecting a coupling to be fitted to the
blower shaft Roots recommends a taper lock style coupling
to ensure proper contact with the blower shaft. Coupling
halves must be fitted to the two shafts with a line to line thru
.001” interference fit. Coupling halves must be warmed up
per coupling manufacturer’s recommendations. Maximum
deviation in offset alignment of the shafts should not exceed
.005” (.13 mm) total indicator reading, taken on the two
coupling hubs. Maximum deviation from parallel of the inside
coupling faces should not exceed .001” (.03 mm) when
checked at six points around the coupling.
When a unit is BELT DRIVEN, the proper selection of sheave
diameters will result in the required unit speed. When selecting
a sheave to be fitted to the blower shaft Roots recommends
a taper lock style sheave to insure proper contact with the
blower shaft. This flexibility can lead to operating temperature
problems caused by unit speed being too low. Make sure
the drive speed selected is within the allowable range for the
specific unit size, as specified under Table 1, page 13.
Belt drive arrangements should employ two or more V-belts
running in grooved sheaves. Installation of the driver is less
critical than for direct coupling, but its shaft must be level and
parallel with the unit shaft. The driver should be mounted
on the inlet side of a vertical unit (horizontal piping) and
on the side nearest to the shaft on a horizontal unit. The
driver must also be mounted on an adjustable base to permit
installing, adjusting and removing the V-belts. To position the
driver correctly, both sheaves need to be mounted on their
shafts and the nominal shaft center distance known for the
belt lengths to be used.
CAUTION: Drive couplings and sheaves (pulleys) should have
an interference fit to the shaft of the blower (set screw types
of attachment generally do not provide reliable service.) It is
recommended that the drive coupling or sheave used have a
taper lock style bushing which is properly sized to provide the
correct interference fit required. Drive couplings, that require
heating to fit on the blower shaft, should be installed per
coupling manufacturer recommendations. A drive coupling or
sheave should not be forced on to the shaft of the blower as
this could affect internal clearances resulting in damage to the
blower.
Engine drive applications often require special consideration to drive coupling selection to avoid harmful torsional vibrations. These vibrations may lead to
blower damage if not dampened adequately. It is often
necessary to install a fly-wheel and/or a torsionally soft
elastic element coupling based on the Engine manufacturer recommendations.
The driver sheave should also be mounted as close to its
bearing as possible, and again should fit the shaft correctly.
Position the driver on its adjustable base so that 2/3 of the
total movement is available in the direction away from the unit,
and mount the assembly so that the face of the sheave is
accurately in line with the unit sheave. This position minimizes
belt wear, and allows sufficient adjustment for both installing
and tightening the belts. After belts are installed, adjust their
tension in accordance with the manufacturer’s instructions.
However, only enough tension should be applied to prevent
slippage when the unit is operating under load. Excessive
tightening can lead to early bearing concerns or shaft breakage.
Before operating the drive under power to check initial belt
tension, first remove covers from the unit connections. Make
sure the interior is still clean, then rotate the shaft by hand.
Place a coarse screen over the inlet connection to prevent
anything being drawn into the unit while it is operating, and
avoid standing in line with the discharge opening. Put oil in the
sumps per instructions under LUBRICATION.
Piping
Before connecting piping, remove any remaining anti-rust
compound from Unit connections. Clean pipe should be no
smaller than unit connections. In addition, make sure it is
free of scale, cuttings, weld beads, or foreign material of any
kind. To further guard against damage to the unit, especially
when an inlet filter is not used, install a substantial screen
GEA19684 ISRB_2008 rev._11.15
5
Fig. 1 - Acceptable Blower Drive Arrangement Options
Acceptable Unacceptable
Top Shaft
INLETDISCHARGE
Motor on Inlet Side of Blower (Top Shaft)
DISCHARGE
Bottom Shaft
INLET
Motor on Inlet Side of Blower (Bottom Shaft)
Above are suggested locations for available accessories.
of 16 mesh backed with hardware cloth at or near the inlet
connections. Make provisions to clean this screen of collected
debris after a few hours of operation. It should be removed
when its usefulness has ended, as the wire will eventually
deteriorate and small pieces going into the unit may cause
serious damage.
Pipe flanges or male threads must meet the unit connections
accurately and squarely. DO NOT attempt to correct misalignment by springing or cramping the pipe. In most cases this
will distort the unit casing and cause impeller rubbing. In severe cases it can prevent operation or result in a broken drive
shaft. For similar reasons, piping should be supported near
the unit to eliminate dead weight strains. Also, if pipe expansion is likely to occur from temperature change, installation of
flexible connectors or expansion joints is advisable.
Figure 3, page 11 represents an installation with all accessory
items that might be required under various operating conditions. Inlet piping should be completely free of valves or other
restrictions. When a shut-off valve can not be avoided, make
sure a full size vacuum relief is installed nearest the unit inlet.
This will protect against unit overload caused by accidental
closing of the shut-off valve.
Need for an inlet silencer will depend on unit speed and pressure, as well as sound-level requirements in the general
surroundings. An inlet filter is recommended, especially in
dusty or sandy locations. A discharge silencer is also normally
suggested, even though Whispair units operate at generally
Top Shaft
DISCHARGE
INLET
Motor on Discharge Side of Blower (Top Shaft)
INLETDISCHARGE
Bottom Shaft
Motor on Discharge Side of Blower (Bottom Shaft)
lower noise levels than conventional rotary blowers. Specific
recommendations on silencing can be obtained from your
local Roots distributor.
Discharge piping requires a pressure relief valve, and should
include a manual unloading valve to permit starting the unit
under no-load conditions. Reliable pressure/vacuum gauges
and good thermometers at both inlet and discharge are
recommended to allow making the important checks on unit
operating conditions. The back-pressure regulator shown in
Figure 3, page 11 is useful mainly when volume demands
vary while the unit operates at constant output. If demand is
constant, but somewhat lower than the unit output, excess
may be blown off through the manual unloading valve.
In multiple unit installations where two or more units
operate with a common header, use of check valves is
mandatory. These should be of a direct acting or free swing-
ing type, with one valve located in each line between the
unit and header. Properly installed, they will protect against
damage from reverse rotation caused by air and material
back-flow through an idle unit.
After piping is completed, and before applying power, rotate
the drive shaft by hand again. If it does not move with uniform
freedom, look for uneven mounting, piping strain, excessive
belt tension or coupling misalignment.
DO NOT operate the unit at this time unless it has been
lubricated per instructions.
6
GEA19684 ISRB_2008 rev._11.15
Lubrication
Due to sludge build-up and seal leakage problems,
Roots recommendation is DO NOT USE Mobil SHC
synthetic oils in Roots blowers.
LUBRICATION: For Units with Splash Lubrication on
Both Ends.
• The specified and recommended oil is Roots Synthetic
oil of correct viscosity per Table 2, page 13.
• The proper oil level should be half way or middle of the
sight gauge when the blower is not operating. DO NOT
OVERFILL OIL SUMP/S as damage to the blower may
occur.
• Oil level may rise or fall in the gauge during operation to
an extent depending somewhat on oil temperature and
blower speed.
• It is recommended that the oil be changed after initial
100 hours of operation.
• Proper service intervals of the oil thereafter are based
on the discharge air temperature of the blower. Please
refer to the information below to properly determine the
oil service intervals.
• If you choose to use another oil other than the specified
and recommended Roots Synthetic, use a good grade
of industrial type non-detergent, rust inhibiting, antifoaming oil and of correct viscosity per Table 2, page
13.
• Roots does NOT recommend the use of automotive
type lubricants, as they are not formulated with the
properties mentioned above.
Normal life expectancy of the specified and recommended
Roots Synthetic oil is approximately 6000 hours with an oil
temperature of 180°F (82°C) or less. As the oil temperature
increases by increments of 15°F (8°C), the oil life is reduced
by half for each 15°F (8°C) increase. Example: Oil temperatures of 195°F (90.5°C) will produce a life expectancy
reduced by half or 3000 hours oil service life.
Normal life expectancy of petroleum based oils is about
2000 hours with an oil temperature of about 180°F (82°C).
As the oil temperature increases by increments of 15°F
(8°C), the life is reduced by half for each 15°F (8°C) increase.
Example: Oil temperatures of 195°F (90.5°C) will produce life
expectancy reduced by half or 1000 hours oil service life.
NOTE: To estimate oil temperature, multiply the discharge
temperature of the blower by 0.88. Example: if the discharge
air temperature of the blower is 200° F, it is estimated that
the oil temperature is 176° F.
High ambient temperatures contribute to increased lubrication
sump temperatures. In situations such as blowers in a enclosure, blowers exposed to radiant heat from other sources,
blowers installed in areas with poor air circulation or ambient
temperatures above 80°F the lubrication sump temperature
should be measured rather than fully rely on the calculation.
Bearings and oil seals are lubricated by the action of the
timing gears or oil slingers which dip into the main oil sumps
causing oil to splash directly on gears and into bearings
and seals. A drain port is provided below each bearing to
prevent an excessive amount of oil in the bearings. Seals
located inboard of the bearings in each headplate effectively
retain oilwithin the sumps. Any small leakage that may occur
should the seals wear passes into a cavity in each vented
headplate and is drained downward. Oil sumps on each end
of the blower are filled by removing top vent plugs, Item (21),
and filling until oil reaches the middle of the oil level sight
gauge, Item (37).
Initial filling of the sumps should be accomplished with the
blower not operating, in order to obtain the correct oil level.
Approximate oil quantities required for blowers of the various
models and configurations are listed in Table 3, page 13.
The oil level should not fall below the middle of the site
gauge when the blower is idle.
Proper lubrication is usually the most important single
consideration in obtaining maximum service life and satisfactory operation from the unit. Unless operating conditions are
severe, a weekly check of oil level and necessary addition of
lubricant should be sufficient. During the first week of operation, check the oil levels in the oil sumps about once a day,
and watch for leaks. Replenish as necessary. Thereafter, an
occasional check should be sufficient.
More frequent oil service may be necessary if the blower is
operated in a very dusty location.
*Roots Synthetic oil is superior in performance to petroleum
based products. It has high oxidation stability, excellent corrosion protection, extremely high film strength and low coefficient of friction. Typical oil change intervals are increased
2-3 times over petroleum based lubricants. Also, Roots
Synthetic oil is 100% compatible with petroleum based oils.
Simply drain the oil in the blower and refill the reservoirs with
Roots Synthetic oil to maintain optimum performance of
your Roots blower.
GEA19684 ISRB_2008 rev._11.15
7
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