Dresser Roots DVJ WHISPAIR Owner's manual

The original ROOTS blower still leads the way™.
DVJ WHISPAIR™
Dry Exhauster
Installation, Operation & Maintenance
Contents
Information Summary ...........................................................1
Warranty and Limitation of Liability........................................2
Operating Characteristics .....................................................3
Operating Limitations............................................................4
Installation ...................................................................... 5-10
Lubrication ................................................................... 10-11
Operation ..................................................................... 12-13
Troubleshooting..................................................................14
Maintenance/Replacements ......................................... 16-22
Sectional Drawings....................................................... 23-26
oCheck shipment for damage. If found, file claim with
carrier and notify nearest Sales Office. See List on last
page.
oUnpack shipment carefully and check contents against
packing List. Notify Sales Office if a shortage appears.
oStore 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.
oRead LIMITATIONS and INSTALLATION sections in this
manual and complete the installation.
oProvide for adequate safeguards against accidents to
persons working on or near the equipment during both
installation and operation. SEE SAFETY PRECAUTIONS.
oInstall all equipment correctly. Foundation design must be
adequate and piping carefully done. Use recommended
accessories for operating protection.
oMake sure both driving and driven equipment is correctly
lubricated before start-up. See LUBRICATION.
oRead starting checkpoints under OPERATION. Run
equipment briefly to check for installation errors and make
corrections. Follow with a trial run under normal operating
conditions.
oIn event of trouble during installation or operation, do
not attempt repairs of Roots furnished equipment. Notify
nearest Sales Office giving all nameplate information plus
an outline of operating conditions and a description of the
trouble.
oUnauthorized attempts at equipment repair may void
Manufacturer’s warranty. Units out of warranty may be
repaired or adjusted by the owner. It is recommended
that such work be limited to the operations described
this manual, using Factory Parts. Good inspection and
maintenance practices should reduce the need for
repairs.
Do These Things To Get The Most From Your ROOTS™Blower
ILRB-3006 0810

DVJ WHISPAIR™Dry Exhauster | 3
Operating Characteristics
DVJ WHISPAIR™ dry vacuum exhausters are covered in this
manual. In size they range from 10 inches through 20 inches
gear diameter. All are equipped with an effective splash oil
lubrication system. From a principle usage standpoint they
are designated as air blowers.
The DVJ rotary lobe blower is a positive displacement type
unit, whose pumping capacity is determined by size, operat-
ing speed and inlet conditions. It employs two double-lobe
impellers mounted on parallel shafts and rotating in opposite
directions within a cylinder closed at the ends by headplates.
As the impellers rotate, air is drawn into one side of the
cylinder and forced out the opposite side against the existing
pressure. The differential pressure developed, therefore,
depends on the resistance of the connected systems.
Effective sealing of the blower inlet area from the discharge
area is accomplished by use of very small operating clear-
ances. (This feature also eliminates rubbing contact between
rotating and stationary parts, hence, internal lubrication is not
required.) Clearances between the impellers during rotation
are maintained by a pair of accurately machined timing
gears, mounted on the two shafts extending outside the air
chamber.
The DVJ blower is used in vacuum service and uses the
same principle as the RAS WHISPAIR™design except the
discharge and slots feeding air back into the cylinder closed
pocket areas all have individual plenums. In vacuum opera-
tion, the discharge pressure differs from atmospheric only
by the backpressure in the discharge system. Atmospheric
pressure air flows into one cylinder slot plenum supplying air
to the closed Pocket B as shown in Position 2 of figure 1 and
through the cross-over pipe (DVJ jet air flow diagram-above
figures) to Pocket A. The atmospheric air, flowing to the
closed pockets, is at a much lower temperature than the
discharge air returned to the pockets in RAS WHISPAIR
design. The cooling effect allows blower operation at higher
vacuum levels without exceeding the blower’s maximum
temperature rise. For closed loop DVJ applications, as shown
in Fig. 4, a portion of discharge gas is recycled back through
a cooler to the cylinder slot plenum to give similar cooling
effects.
No attempt should ever be made to control capacity by
means of a throttle valve in the intake or discharge piping.
This increases the power load on the driver, and may
seriously damage the blower. Likewise, if a possibility exists
that flow to the blower inlet may be cut off during normal
operation of a process, then an adequate vacuum relief valve
should be installed in the inlet line near the blower. A pressure
type relief valve in the discharge line near the blower is also
strongly recommended for protection against cut-off or
blocking in this line.
When a belt drive is employed, blower speed can usually be
adjusted to obtain desire capacity by changing the diameter
of one or both sheaves. In a direct coupled arrangement, a
variable speed motor or transmission is required, or air may
be vented through a manually controlled unloading valve and
silencer. If discharge air is returned to the blower inlet, it must
go through a cooling by-pass arrangement.
Before making any change in blower capacity or
operating conditions, contact the nearest Sales Office for
specific information applying to your particular blower. In all
cases, operating conditions must be maintained within the
approved range or pressures, temperatures and speeds as
stated under LIMITATIONS. Also, the blower must not be
used to handle air containing liquids or solids. Serious
damage to the rotating parts will result.
Figure 1 - DVJ WHISPAIR™Operating Principle
Position 1
A
B
Position 2 Position 3

4 |Dresser Roots
Operating Limitations
To establish and maintain continued satisfactory performance,
and Roots blower must be operated within certain approved
limiting conditions. The Manufacturer’s warranty is, of course,
contingent on such operation.
Any unnecessary restrictions of discharge flow or atmospheric
air inlet to the cylinder slots reduces the cooling air flow and
limits blower operation as the maximum temperature rise
will occur below the normal limits of vacuum level. For an
open loop system, the discharge pressure must not exceed
0.2" H2O per 100 FPM gear speed. Example - 10" GD
unit running at 1500 rpm, maximum discharge pressure =
0.262*10*1500*0.2/100=7.9" H2O. This also applies to close
loop system, this is the pressure difference between the blower
discharge and the casing bleed back port. The pressure drop
through the jet filter/silencer must not exceed 10" H2O. The
the listed maximum allowable temperature rise (increase in air
temperature between inlet and discharge) for any particular
blower may occur well before maximum speed or maximum
pressure rating is reached. Temperature rise then is the
limiting condition. In other words, the operating limit is
always to be determined by the maximum rating reached first.
It can be any one of the three: pressure/vacuum, temperature
or speed.
Be sure to arrange connections or taps for thermometers and
pressure or vacuum gauges at or near the inlet and discharge
connections of the blower. These, along with a good tachom-
eter, will enable periodic checks of operating conditions.
Note - Some special purpose blowers may be assembled
with nonstandard clearances other than shown in Table 8 or 9.
These units may be operated at vacuum and or temperature
rises higher than those listed in applicable Table 1. Before
doing so however, request specific approval from the nearest
Sales Office. Normally, when a blower is operated at the
design condition stamped on its nameplate, the specified limits
apply.
VACUUM - With the discharge going to atmospheric pressure,
the inlet suction or vacuum in inches of mercury (kPa) must not
be greater than the values listed for the specific frame size. The
pressure rise in pounds per square inch (kPa) between blower
inlet and discharge, must not exceed the figure listed for the
specific blower and frame size concerned. The blower case
is rated for a maximum pressure of 25 PSI (172 kPa) gauge
regardless of blower size.
TEMPERATURE - Various blower frame sizes are approved
only for installations where the following temperature limitations
can be maintained in service.
A. Maximum temperature rise (T.R.) in Fahrenheit degrees
(°C) must not exceed listed values when the inlet is at
ambient temperature. Ambient is considered as the
general temperature of the space around the blower.
This is not outdoor temperature unless the blower is
installed outdoors.
B. If inlet temperature is higher than ambient, the listed
allowable temperature rise values must be calculated
using blower selection program (Contact Sales Office if
you do not have access to the program).
SPEED RANGE - Blowers may be operated at speeds up to
the maximums listed for the various frame sizes. They may be
direct coupled to suitable constant speed drivers if vacuum/
temperature conditions are also within limits. Splash lubricated
blowers should not be operated below 1000 FPM gear speed
for proper lubrication.
Frame Size Inlet Vacuum Temperature Rise Speed
Inches HG mm HG. °F °C RPM Maximum
1016 27.0 684 275 153 1800
1021 27.0 684 300 167 1800
1220 27.0 684 275 153 1500
1222 24.0 610 275 153 1500
1428 22.5 571 300 167 1300
1431* 22.0 558 300 167 1300
1639 18.5 470 300 167 1130
1643 16.5 420 300 167 1130
1833 24.0 610 300 167 1000
1838 21.5 546 300 167 1000
Table 1 - Maximum Allowable Operating Conditions - DVJ
*Requires GE drive arrangement above 20" Hg.

DVJ WHISPAIR™Dry Exhauster | 5
INSTALLATION
The DVJ blower should have a full-sized silencer installed
on the discharge and a minimum length of full size piping,
if necessary, for the installation. Back pressure created by
silencer restriction and pipe losses reduces the jet inlet flow
and increases blower temperature rise. No valves should be
used in the discharge piping.
The 1016 and 1220 blower has a temporary cover installed
on one cylinder slot inlet port at the factory and a permanent
metal cover on the other. A full size acoustic absorption type
silencer should be installed in place of the temporary cover,
however, the cover and silencer may be reversed on the
cylinder slot plenum ports if the installation requires it. Some
type of protection such as a filter screen is necessary to
stop foreign particle entry through the cylinder slots. Outside
installations may also require some weather protection to
prevent the entry of rain or snow. Jet inlet restriction will
cause an increase in blower temperature rise and should
be checked as a possible cause if temperature rise limits
operation to a vacuum level less than maximum allowable.
Technical assistance at installation by a factory Service
Engineer is usually not required for the smaller units, frame
series 1000 through 1400. Workmen with general experience
in installing heavy machinery should be able to complete
a satisfactory installation. Information in this manual is
supplemented by the more detailed discussions of founda-
tions and piping in API recommended practice 686 and
the Compressed Air and Gas Handbook, published by the
Compressed Air and Gas Institute, New York City and the
American Petroleum Institute, Washington, D.C. However, a
Service Engineer may be employed for assistance or for final
checking of an installation.
Handling of the equipment should be accomplished by
methods conforming to safe practice for the weight involved.
Weight of a bare unit, without base plate, driver or acces-
sories will range from about 1 ton (910 kg) for the smallest to
approximately 7 tons (6350 kg). On such units, an eyebolt is
provided near each end for lifting. A unit mounted on a base
plate should be lifted only by the four lifting lugs provided.
Weight in this case will be greater than the following figures.
Before lifting with eyebolts, test one for tightness and
fractures by tapping with a hammer. Direction of pull on the
bolts during lift should be nearly vertical. Since a considerable
cable angle will usually be unavoidable, place a stiff spreader
between the eyebolts to take the side strain, and adjust cable
lengths so that the unit is approximately level during the lift.
A harness featuring four lifting hooks is required to lift
base-mounted units. After inserting the hooks in the lifting
lugs, block the chains out on the sides to avoid placing the
unit under strain. At the same time, adjust lengths to produce
a level lift.
LOCATION of the installation is generally not a critical matter.
A clean, dry and protected indoor location is to be preferred.
However, an outdoor location will give satisfactory service
if correct lubrication for expected temperatures is provided.
Effect of such a location on driver and other equipment must
also be considered.
PROTECTION of internal machined surfaces against normal
atmospheric corrosion is normally provided at the factory,
using a vaporizing inhibitor. Markings on the flange covers will
indicate this protection. Maximum period of protection is one
year under average conditions, if flange covers and closing
seals are not removed. Protection against chemical or
salt water atmosphere is not provided. Leave covers
and tape seals over all openings as long as possible during
installation to avoid loss of protection.
If there is to be an extended period between installation
and start up, the following steps should be taken to insure
corrosion protection:
1. Coat internal of gearbox and drive end bearing covers
with a vapor phase rust inhibiting liquid such as Nox-
Rust VCI-10. Use Zerust vapor capsules in the inlet port
of cylinder. Repeat once a year or as conditions may
require. VCI-10 is oil soluble and does not have to be
Blower
Size
Impeller Ends Impeller Strips To Cylinder Impeller Lobes Max.
Temp Rise
-°F
Thrust
Ends
Gear End
Min. Inlet Center Disch. Fronts Backs
1016 .010/.012 .023/.027 ---- ---- .014/.016 .010/.012 .014/.016 .020/.024 .010/.014 275°
1021 .010/.012 .032/.036 ---- ---- .016/.018 .010/.012 .016/.018 .022/.026 .010/.014 300°
1220 .010/.012 .034/0.38 ---- ---- .015/.017 .011/.013 .015/.017 .021/.025 .011/.015 275°
1222 .011/.015 .037/.041 ---- ---- .015/ .017 .011/ .013 .015/ .017 .021/ .025 .011/ .015 275°
1428 .013/.015 .032/.036 ---- ---- .019/.021 .012/.014 .019/.021 .022/.026 .012/.016 300°
1431 .014/.016 .035/039 ---- ---- .019/.021 .012/.014 .019/.021 .022/.026 .012/.016 300°
1639 .016/.018 .048/.052 ---- ---- .025/.027 .015/.017 .025/.027 .024/.028 .014/.018 300°
1643 .018/.020 .050/.054 ---- ---- .026/.028 .016/.018 .026/.028 .024/.028 .014/.018 300°
1833 .015/.017 .042/.046 ---- ---- .024/.026 .015/.017 .024/.026 .025/.029 .015/.019 300°
1838 .017/.019 .048/.052 ---- ---- .024/.026 .015/.017 .024/.026 .025/.029 .015/.019 300°
Table 2 - DVJ Clearances

6 |Dresser Roots
removed before lubricating. If desired, VCI-10 may be
removed from within the cylinder shortly before start up
by spraying fine mist of petroleum solvent through the
blower while it is running at a slow speed with open inlet
and discharge, or it can remain in the blower if it is not
harmful to the operation of the connected system. VCI-
10 is a product of Daubert Chemical Co., Oak Brook, IL.
2. Paint shaft extension, inlet and discharge flanges, and
all other exposed surfaces with Nox-Rust X-110 or
equivalent.
3. 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 VCI-10
vapor will escape and lose its effectiveness.
4. Units are not to be subjected to excessive vibration
during storage.
5. Rotate drive shaft three or four revolutions every two
weeks.
6. Prior to start up, remove flange covers on both inlet and
discharge and inspect internal to insure absence of rust.
Check all internal clearances. Also, at this time, remove
gearbox and bearing covers and inspect gear teeth and
bearings for rust.
When ready to connect piping, remove main flange covers
and inspect blower interior for presence of foreign particles or
dirt adhering to machined surfaces. Clean out such material
by washing carefully with a petroleum solvent then rotate
impellers manually to make sure they turn freely. Also use
the same solvent to remove the anti-rust coating from flange
faces and any other surfaces. Note: interior cleaning is not
required if no dirt is found.
FOUNDATION design depends on local soil conditions and
several other factors and can only be discussed generally
here. Additional information will be found in the publication
referred to at the beginning of this section. For satisfactory
operation of supported equipment, a concrete foundation
must be rigid, must have minimum defections, and must be
free from resonant frequencies in the operating speed range
of the equipment.
Length and width dimensions of the foundation should
provide at least 6 inches (150 mm) from any edge to the
nearest machine anchor bolt, as located from the certified
manufacturer’s general arrangement drawing. Depth
dimension should be determined by design, but a minimum
practical depth is considered to be twice the distance
between shaft centers (or gear diameter) of the unit, or
sufficient depth to attain a concrete mass a minimum of 1-1/2
times the weight of the blower and motor. The concrete
block should be permitted to cure for a minimum of 28 days
before the blower is grouted in place. Any block distortions
during curing then will have little or no affect on equipment
and alignment. To simplify machine leveling and provide good
grouting bond, the top of the foundation should be struck-off
as level as possible but left with a rough surface.
Spring-type vibration isolating mounting are not recommended
for use directly between the operating equipment and the
foundation. Where such mountings are required, they should
be designed to carry a reinforced concrete slab on which the
equipment is mounted. This slab must have good rigidity against
bending and twisting, and the suspension system will require
careful adjustment to produce a reasonably level condition
during operation. All piping will require flexible sections and
supports to reduce connection strains on the unit to a minimum.
Direct use of structural framing members for mounting is not
recommended. If unavoidable, it should be restricted to
units of the smaller frame sizes, and spring-type mountings
should not be used. Structural members must be rigid, and
will probably require reinforcement if part of a building. Noise
transmission can be reduced by use of a cork isolating pad.
This can be 1 to 2 inch (25-50 mm) thickness, bedding on
a full steel plate attached to the structure and carrying rigid
concrete slab on which the equipment is mounted.
ANCHOR BOLTS are to be placed within the foundation
forms before concrete is poured. Foundation bolts installed
as shown in Figure 2, with diameter and length as in Table 2
are recommended. The bolts must be located as accurately
as possible from dimensions on certified installation drawing.
To obtain a bolt location tolerance of 1/8" (3mm), use of
drilled templates firmly secured to the foundation forms is
recommended.
The bolt sleeves shown, if kept centered around the bolts
and free of concrete, will allow bolts to be sprung enough to
correct for small variations in bolt setting and machine drilling.
The sleeves are filled in the final grouting operation. Bolt
positions should be adjusted vertically so that the top ends
will extend at least 1-1/2 diameters above the soleplate or
taper washer, or as shown on the installation drawing.
Jack screws are provided to make leveling the height adjust-
ments easier. Steel plates, approximately 4" x 4" x 1/2 " (100 x
100 x 13 mm) should be placed on the foundation under each
jack screw location. Plates and anchor bolts are not furnished
as standard accessories.
LEVELING is very important and should be performed with
care, using a good machinists level having a ground glass
bubble vial. A setting as level as possible in all directions is
the result to be worked toward. Blowers should be leveled
from drive shaft and pipe flanges. Machined baseplates
have pads running in both length and width directions. On
Figure 2 - Typical Anchor Bolt Detail

DVJ WHISPAIR™Dry Exhauster | 7
soleplates, the machined top surfaces are used for leveling.
Scrape pads or surfaces clean, and remove burrs on high
points with a flat file.
When blower and driver have been factory mounted on
a common baseplate, the assembly is to be treated as a
unit for leveling purposes. Use the jack screws to establish
grouting space under the base flanges, and to level the base.
Adjust these screws until the indicated variation from level
does not exceed .001” per foot (.08 mm per m) in either
length or width. Any variations should all be in the same
direction, to minimize twist. The maximum allowable twist
is considered to be .001” per horizontal foot (.08 mm per
horizontal m) measured between any two sections of the
base.
Units mounted on soleplates are to be leveled in a similar
manner. The plates should be large enough to provide exten-
sions for leveling in both length and width on the finished
upper surfaces. Fasten the plates solidly to the blower feet,
which are machined flat and parallel to each other, then install
and level the blower carefully, using jack screws, shims or
wedges for adjusting.
When a satisfactory condition of level is obtained, turn the
anchor bolt nuts down snug but not tight. Elimination of twist
here is very important, and minor adjustments can be made
with shims directly under the blower feet.
ALIGNMENT of the drive shafts when the blower unit and
its driver are direct coupled requires careful attention. This
precaution will not only help insure satisfactory coupling
operation, but will minimize chances for damage to either
driving or driven unit from vibration or thrust forces.
In package units with driver and blower mounted on a
common baseplate, the two shafts will have been put in
approximate alignment at the factory. However, baseplate
deflections can occur during shipping and installation. A
close coupling alignment should be obtained during leveling,
so that only small final adjustments will need to be made
after grouting. In a soleplate type installation, the separately
mounted driver must be positioned, leveled and aligned as
part of the installation procedure. Whether it is on soleplates
or on its own base, shims of 1/16” to 1/8” (2-3 mm) thick-
ness placed directly under the driver feet before setting will
permit more accurate final alignment. Spacing between the
two shaft ends as required by the coupling must also be
established. If a motor is being used that has end-play in the
shaft, be sure its rotor is located on magnetic center before
setting this spacing.
When blower is driven through V-belts, the driver must
be mounted on an adjustable base to permit tightening or
removing the belts. In this case the driver shaft height is of
no concern, but it must be parallel to the blower shaft and
level. To position the driver properly, both sheaves need to be
mounted on their shafts, and the shaft center distance must
be known.
The blower sheave, usually the larger one in diameter, must
be of the narrow hub type. Install it so that its inner hub face
is not more than 1/4” (6 mm) away from the bearing housing
end cover. The driver sheave should also be mounted as
close to its bearing as possible. Now position the driver so
that faces of the two sheaves are accurately in line, with
the adjustable base so located as to make 2/3 of its total
movement available in the direction away from the blower.
This positioning provides minimum belt wear and slip, and
allows sufficient adjustment for installation and tightening of
belts. Do not install belts until grouting has set and anchor
bolts are tightened.
Blowers intended for driving by V-belts may be provided with
an extended drive shaft and an additional outer bearing to
handle the side pull of the drive. They may be recognized
by the extended housing for the outer bearing. If necessary,
these units may also be used for direct coupling to the driver.
Blowers intended specifically for direct coupling have no
outer bearing, and may be seriously damaged if used for belt
drive. Consult your Sales Office for approval before belting
these units.
GROUTING follows completion of leveling and preliminary
alignment. Assuming the foundation has been properly cured,
its top surface should first be roughened by chipping to
remove glazed areas and oil or grease removed with a strong
hot detergent or caustic solution.
Grouting serves not only to compensate for surface irregulari-
ties in the foundation and machine base but also to provide
restraint against shifting. Anchor bolts are used
for hold-down only. Therefore, the grout must be adequate
thickness under the soleplate or base flange, must flow into
anchor bolt sleeves and all interior cavities, and must have
minimum shrinkage during the setting period. By virtue of the
open frame design, it is recommended that the bed¬plate
be filled with concrete to a level equal to the top of the main
channels. Special grouting materials designed to counteract
shrinkage are commercially available, and are often preferred
Table 2A - Standard Anchor Bolts in Inches
Table 2B - Standard Anchor Bolts in Centimeters
Unit
Frame
Size
For Soleplates For Baseplates
Bolts Sleeves Bolts Sleeves
Dia. Lgth. I.D. Lgth. Dia. Lgth. I.D. Lgth.
1000 1 25 3 18 3/4 18 2-1/2 12
1200 1 25 3 18 3/4 18 2-1/2 12
1400 1-1/8 25 3 18 3/4 18 2-1/2 12
1600 1-1/8 25 3 25 1 25 3 18
1800 1-1/4 25 3 25 1 25 3 18
2000 1-1/4 25 3 25 1 25 3 18
Unit
Frame
Size
For Soleplates For Baseplates
Bolts Sleeves Bolts Sleeves
Dia. Lgth. I.D. Lgth. Dia. Lgth. I.D. Lgth.
1000 2.4 64 7.5 46 2.0 46 6.5 30
1200 2.4 64 7.5 46 2.0 46 6.5 30
1400 3.0 64 7.5 46 2.0 46 6.5 30
1600 3.0 64 7.5 46 2.4 64 8.0 46
1800 3.0 64 7.5 46 2.4 64 8.0 46
2000 3.0 64 7.5 46 2.4 64 8.0 46

8 |Dresser Roots
to cement. The manufacturer’s instructions should be fol-
lowed in using these materials. Care must be exercised when
employing non-shrink additives with cement, as too much
can be worse than none. Any gas forming or air-entraining
additives should be avoided completely, since they tend to
reduce grout strength.
Wait at least 24 hours before tightening anchor bolts or
connecting any piping. When jack screws have been used for
leveling, make sure the bottom of the leveling screw is treated
according to grout manufacturer’s instructions so that level-
ing screw can be backed off. Such points of concentrated
loading are likely to wear during machine operation, resulting
in loose anchor bolts. Final bolt tightening should be only
enough to hold the machine firmly against the foundation and
prevent vibration.
After all anchor bolts are secured, recheck the blower for
twist and level. Working from the finished pad on top of the
cylinder, make corrections to meet the requirements specified
under LEVELING by shimming under the blower feet. Then
rotate the drive shaft by hand to make sure both impellers
turn freely at all positions.
When the blower is direct coupled to its driver, final alignment
of the two shafts should be accomplished next by adjusting
the shims under the driver feet. This needs to be done with
the greatest possible care. Even though a flexible coupling
can accept some degree of misalignment, it should not be
forced to compensate for careless workmanship. The flexing
or sliding member in a coupling will transmit undesirable
forces between the two shafts in proportion to the degree
of misalignment, thus promoting vibration and unnecessary
wear problems.
MISALIGNMENT can be of two basic types, offset and
angular, but usually it will be a combination of both. For
satisfactory coupling operation it is recommended that the
following limits be used: maximum deviation in offset align-
ment not greater than .005” (.13 mm) total indicator reading
on the coupling hubs; maximum deviation from parallel of the
inside coupling faces not greater than .001” (.03 mm) when
checked at six points. Where driver is a steam turbine, the
final alignment should be made with the turbine at operating
temperature in order to allow for shaft movement resulting
from expansion.
A coupling that has been Factory installed as part of a pre-
assembled package should receive the same final alignment
check as outlined above. It will need to be disassembled by
removing cover bolts, removing or drawing back the two
cover halves, and removing the internal member. In some
cases the latter item may have been packed separately for
shipment. After necessary adjustments for alignment are
completed, lubricate the coupling with grease as specified by
its manufacturer and assemble.
A belt-driven installation should require no realignment if all
items were correctly positioned and leveled before grouting.
Belts may be installed now by adjusting driver position toward
the blower sufficiently to permit belts to be laid in their sheave
grooves easily. Do not pry or roll them into place. Before
doing this, inspect all grooves for burrs, rough spots or oil
that might shorten belt life. If equipment is not to be operated
immediately, leave the belts slack.
Proper tensioning of the drive for operation should be done in
accordance with manufacturer’s recommendations, keeping
in mind that excessive tension can seriously overload shaft
bearings and also lead to premature drive failure. Under-
tensioning can produce slippage, with consequent loss of
blower capacity in addition to belt damage.
Make sure at this point that driver rotation is correct to
produce the blower shaft rotation indicated by an arrow
near the shaft. Blowers are not reversible, hence drive shaft
rotation and discharge flange location are predetermined in
manufacturing assembly. Figure 4 illustrates the assembly
options available by specification on original order, to meet
piping and drive requirements.
PIPING must be clean, and should be sized so that air
velocity in the line will not exceed 100 feet per second (30 m
per second). When a blower is being operated at or near its
maximum volume rating, the pipe size should not be smaller
than the blower connections. Where possible, use long radius
elbows to insure smooth flow. Design the piping layout so
that no strains are placed on the blower, either from weight or
expansion forces. This means providing adequate supports,
anchors, and expansion joints or loops.
Installation of a spool-type rubber expansion joint near the
blower inlet connection is recommended. A similar unit
with control elements added to minimize piping vibrations
may be required near the discharge. Use of SNUBBERS or
SILENCERS in the inlet or discharge piping will be dependent
on such factors as blower speed, operating pressure, length
and kind of piping, and consideration of sound level require-
ments in the general surrounding area. For specific silencer
recommendations refer to the nearest Sales Office.
Inlet piping should be completely free of valves or restrictions,
but when a shut-off valve cannot be avoided, make sure a full
size vacuum relief valve is installed near the blower inlet con-
nection. See Figure 5. This will protect against an overload
caused by accidental valve closing. Further protection can be
provided by installation of a dependable pressure sensitive
device with alarm or shutdown action.
Flow Pipe Diameter (Inches)
12" 16" 20" 24" 30" 36"
2,500 3.0 1.1 0.3 0.3
5,000 12.7 3.9 1.7 0.8
10,000 15.5 6.4 3.0 1.3
15,000 14.4 7.2 2.8 1.4
20,000 12.7 5.1 2.4
30,000 11.4 5.5
40,000 12.3
Approximate Screen Pressure Drop, Inches H2O
(16 Mesh, .020" Wire Dia.)

DVJ WHISPAIR™Dry Exhauster | 9
Figure 3 – Installation with Suggested Locations for Available Accessories (DVJ)
Figure 4 – Installation with Suggested Locations for Available Accessories (RGS-DVJ)

10 |Dresser Roots
Lubrication
A - SEPARATE OPPOSITE GEAR END RESERVOIRS
A simple and reliable splash lubrication system is employed in
ROOTS®blowers. All friction parts - gears, bearings and shaft
seals - are lubricated either by dipping directly into oil reser-
voirs or by receiving splash oil from other rotating parts. All
reservoirs require the same grade of oil as specified in Table
3 for various ambient temperature ranges at the installation
site. Reference to the appropriate assembly drawing, Figure
15, will assist in understanding of the following discussion.
At the opposite gear end of the blower, the upper (or driven)
shaft bearing is lubricated from its own oil reservoir, formed
by the bearing carrier (6) and the deep blind end cover (5A).
At a normal oil level, bearing rollers dip into the oil as they
roll through the bottom of their raceway. The oil picked up
is carried over the top by bearing rotation, and some of it
transfers to the shaft behind the bearing to lubricate the
dynamic lip-type inboard seal (27). A slight amount of oil may
work through this seal, but it will be thrown off by the shaft
slinger, and further prevented from reaching the air chamber
by a labyrinth type seal where the shaft passes through the
headpiece. The chamber between the two sealing points
is vented to atmosphere and serves not only to drain any
seal leakage but also to keep the lubrication system at
atmospheric pressure.
At the lower (driving) shaft the arrangement is the same as
described above when a short shaft for direct coupling is
provided. Here an outboard shaft seal (23) is provided in
the end cover (5). On V-belt driven blowers the drive shaft
and bearing carrier (63) are extended and provided with and
additional inboard bearing (60). This creates a larger reservoir
requiring about three times as much oil to fill. Lubrication is
the same as for the shorter shaft, except that two protruding
screws (96) are provided to insure adequate splash oil for
bearing (60).
At the gear end of the blower the bearings, seals and timing
gears are enclosed by a gearbox containing a double
(primary and secondary) oil sump arrangement. In a vertical
style blower the secondary sump is formed of sheet steel
and contoured around the bottom half of the lower gear. It is
fed with oil at a controlled rate from the surrounding primary
sump in the gearbox itself, through a metering orifice in the
secondary wall. The lower gear teeth pick up oil and carry
it to the meshing point with the upper gear, from where it is
splashed onto oil control shields with leaders that direct the
oil to the two bearings. A dam at each bearing maintains
the desired oil level there, with excess overflowing into the
gearbox primary sump. Inboard sealing of the shafts is the
same as at the drive end. In a horizontal style blower the
gear end lubrication arrangement is identical, except that a
secondary sump is formed around each gear and the total oil
capacity is more than doubled.
Note - A good grade of industrial type non-detergent,
anti-foaming oil should be used when the average of blower
inlet and discharge temperature is 125°F (52°C) or lower.
Oil should be changed after the first 100 hours of operation.
After initial oil change, normal oil change periods under these
conditions may be considered as 2000 operating hours.
Table 3 - Recommended Lubrication Oils
Ambient
Temperature
Viscosity Range, SSu at
100% °F (83 °C)
Above 90 °F (32°C) 1000-1200
32° to 90°F (0°-32°C) 700-1000
0° to 32°F (-18°- 0°C) 500-700
Below 0°F (-18°C) 300-500
During initial operation, install a temporary corrosion resistant
screen at the compressor inlet connection. Screen should be
made of 16 mesh (.020” diameter) wire backed with 2 mesh
wire cloth. Backing cloth-wire diameter shall be a minimum
of 0.063” diameter for 12” pipe, 0.080” diameter for 16” pipe,
0.105” diameter for 20” pipe, and 0.120” diameter for 24”
pipe. For 30” and 36” pipe use 1 mesh backing cloth with a
minimum of .180” wire diameter for 36” pipe. The table below
gives approximate screen pressure drop. A manometer
connected to read pressure drop across the screen will
indicate when it needs cleaning. Do not allow pressure drop
to exceed 55 inches H2O. Clean and replace the screen
until debris no longer appears. Do not leave it installed
permanently, as the wire will eventually deteriorate and pieces
may go into the blower causing serious damage. (Typically,
screens are installed 1-2 days of operation.)
Discharge piping requires a pressure relief valve, and should
also include a suitable pressure gauge and a manually
operated unloading valve. The latter permits starting under
no-load conditions. The optional back pressure regulator
shown in figure 5 will be required if volume demands vary
while blower operates at constant speed. It may be vented
if only air is being handled. A vent silencer may be required,
depending on permissible sound levels in the general
surroundings.
In some installations, particularly where two or more blowers
discharge into a common header, it is recommended that a
direct acting or free swinging check valve be provided in each
discharge line. These valves, properly installed protect against
damage resulting from reverse rotation caused by back flow
through an idle blower.
In making pipe connections to the blower, use special care
in lining up the mating flanges. They must contact squarely
and accurately, without imposing strain on the blower casing.
Any attempt to draw flanges together by force will probably
distort the blower and cause internal contacts. Also, the
blower should not carry more than the weight of one pipe
fitting at each connection. After bolting up the flanges, rotate
the drive shaft by hand to check for rubbing contacts caused
by strains or dirt.

DVJ WHISPAIR™Dry Exhauster | 11
At higher temperatures these oils may turn black and leave
carbon deposits. For average temperatures above 125°F
(52°C) it is recommended that oil with an efficient oxidation
inhibitor be used, and that change interval be reduced. Shell
TELLUS is a suitable oil type with the required characteris-
tics, and equivalent oils from other suppliers are assumed
to be comparable in performance. Suggested oil change
periods for the higher operating temperatures are as follows:
Average Temp. °F (C°) Operating Hrs.
Below 150 (65) 1000
151-160 (66-71) 500
Above average temperature of 180°F, use of synthetic oil like
ROOTS Synfilm ST Synthetic Oil is specified.
On the gearbox and the two opposite gear end bearings
sumps, oil levels are indicated in sight windows. All three
sight windows are completely unobstructed circular discs,
and the oil level should always be in view.
Approximate capacities in gallons or fluid ounces for the three
sump locations are given in Table 4 as a guide. Actual filling
requirements may vary slightly from the listed figures. Select
a good industrial grade of oil per Table 3 for the existing
ambient temperature conditions.
Filling of the oil sump must be performed with the blower not
operating, so that correct levels may be established. At the
gearbox, remove vent plug (37) in the top and pour in slightly
less oil than indicated in Table 4 for the blower size con-
cerned, or until the oil rises to the center of the sight glass.
Wait several minutes for the levels to equalize between the
primary and secondary sumps, then add more oil if needed,
or drain excess at plug (67).
The opposite gear end sumps use constant level oilers. To fill
the sumps, remove the top glass reservoir. Fill it with oil and
place it on its holder and let the bottle empty to fill the sump.
To obtain proper oil level in the sump, that is to the center of
the sight glass (90), pull out level adjuster “A” (see fig. 5) and
raise or lower cross-arm “B” as needed, secure “B” with lock
“C” and drop assembly back into lower reservoir and replace
bottle. Note - Raising “B” raises oil level and lowering “B”
lowers oil level.
During operation the sump levels can be expected to
fluctuate. At the gearbox sight window the level will rise as
a result of oil being thrown out of the secondary sump (oil
pan) into the primary sump. A satisfactory oil level is assured
as long as it is visible in the window. A blower should not be
operated when the oil is either above or below the circle on
the sight window.
Oil levels at the opposite gear end will fall slightly during
operation because of the apparent “loss” carried in the
bearings and on the shafts. To be satisfactory, the level must
be visible in the sight glass.
During the first week of blower operation, check the oil
level daily and watch for leaks. Replenish oil as necessary.
Thereafter, an occasional check should be sufficient. Drain
plugs (67 and 88) are provided at the bottom of gearbox and
bearing sumps.
B - COMMON OPPOSITE GEAR END RESERVOIRS
Some blowers are equipped with a common reservoir on the
opposite gear end. The small reservoirs are replaced with a
large cover similar to that covering the gear end. The oil is
transmitted to the bearings by use of a slinger plate which
dips into the oil. The oil is then captured and directed to the
bearings by oil control shields. Reference to the sectional
drawings at the back of this manual will help in understanding
this system.
Figure 5
Table 5 – Common O.G.E. Sump Capacity
Table 4 - Oil Sump Capacities
Blower
Frame
Size
Gearbox - gallons (liters) Opposite Gear End Bearings - fluid oz. (liters)
Vertical Horizontal Driven Shaft Drive Shaft Coupled Drive Shaft Belted
1000 ¾(2.8) 2 (7.6) 4 (.12) 4 (.12) 12 (.36)
1200 1½(5.7) 3½(13) 5 (.15) 5 (.15) 16 (.47)
1400 1¾(6.6) 4 (15) 8 (.24) 8 (.24) 28 (.83)
1600 2½(9.5) 5¾(22) 9 (.27) 9 (.27)
1800 3 (11) 7½(28) 16 (.47) 16 (.47)
2000 4 (15) 9¾(37) 19 (.56) 19 (.56)
Blower
Frame
Size
Gearbox Gallon/liters O.G.E. Gallon/liters
Vertical Horizontal Vertical Horizontal
1000 3/4 (3.3) 2 (7.6) 3/4 (2.8) 2 (7.6)
1200 1-1/2 (5.7) 3-1/2 (13) 1-1/2 (5.7) 3-1/2 (13)
1400 1-3/4 (6.6) 4 (15) 1-3/4 (6.6) 4 (15)
1600 2-1/2 (9.5) 5-3/4 (22) 2-1/2 (9.5) 5-3/4 (22)
1800 3 (11) 7-1/2 (28) 3 (11) 7-1/2 (28)
2000 4 (15) 9-3/4 (37) 4 (15) 9-3/4 (37)

12 |Dresser Roots
Operation
Before operating a blower under power for the first time,
recheck the unit and the installation thoroughly to reduce the
likelihood of troubles. Use the following procedure check list
as a guide, but consider any other special conditions in the
installation.
1. Be certain that no bolts, tools, rags or dirt have been
left in the blower air chamber.
2. Be certain that inlet piping is free of any debris. Use
of the temporary protective screen at the blower inlet
as described under INSTALLATION is strongly recom-
mended during early operation. If an outdoor intake
without filter in used, be sure the opening is clean and
protected by a strong screen.
3. Check blower leveling, drive alignment, belt tension and
tightness of all mounting bolts if installation is not recent.
4. Turn drive shaft over by hand to make sure impellers will
rotate without bumping or rubbing at any point.
5. Check the blower lubrication system. Oil level should be
at the center of the sight glasses.
6. Make sure driver (and gear unit if supplied) are properly
lubricated. Check that power is available and that all
electrical overload and safety controls installed, con-
nected and in operating condition.
7. Open the manual unloading valve in the inlet air line,
and make sure that any blocking valve in the discharge
piping is open.
8. Bump blower a few revolutions with driver to check
direction of rotation and to see that both units coast
freely to a stop.
9. Start blower, let it accelerate to full speed, then shut off.
Listen for any knocking sounds, both with power on and
also as it slows down.
10. If no problems have appeared, restart unit and operate
for 5 to 10 minutes under no-load conditions as para-
graph 7. Check the cylinder surfaces all over by feeling
to locate any hot spots indicating impeller rubs. Continue
to listen for noises and watch for changes in vibration. If
all conditions are acceptable, proceed as follows:
11. Continue operating, but gradually close the inlet unload-
ing valve to establish normal operating conditions as
closely as possible. It is recommended that pressure and
vacuum gages and good thermometers be used in both
inlet and discharge locations to permit determination of
pressure rise and temperature rise across the blower.
Observe the vacuum increase as the unloading valve is
closed, and do not allow it to exceed the rating of the
specific blower as listed under LIMITATIONS.
12. All conditions being satisfactory to this point, continue
the run for about one hour. Observe the vacuum and
temperature rise periodically to make sure neither
exceeds specified limits. Continue to check for
noises and hot spots, and observe oil level behavior
at the three sumps. If trouble appears, refer to the
TROUBLESHOOTING CHECKLIST for suggested
remedies.
The unit should now be ready for continuous duty under full
load. During the first several days, make periodic checks
to be sure that all conditions remain reasonably steady and
within limits. These checks may be especially important if the
unit is part of a process system where conditions may vary.
At the first opportunity, stop the blower and clean or remove
the protective inlet screen. At the same time, verify leveling,
coupling alignment or belt tension, and anchor bolt tightness.
Should operation of an air blower prove that its capacity is a
little too high for actual requirements, a small excess may be
blown off through the manual unloading or vent valve. Never
rely on the pressure relief valve as an automatic vent.
Such use may cause the inlet vacuum to become excessive,
and can also result in failure of the valve itself. If blower capac-
ity is low, refer to TROUBLESHOOTING CHECKLIST before
contacting the nearest Sales Office for recommendations. Be
prepared to give all operating conditions and requirements.
Safety Precautions
For equipment covered specifically or indirectly in
this instruction book, it is important that all personnel
observe safety precautions to minimize the chances
of injury. Among many considerations, the following
should particularly be noted:
• Blowercasingandassociatedpipingoraccesso-
ries 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 physi-
cal injuries. Do not reach into any opening in the
blower while it is operating, or while subject to
accidental starting. Cover external moving parts
with adequate guards.
• Disconnectpowerbeforedoinganywork,and
avoid by-passing 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.
• Stayclearofopeninletpiping(suctionarea)of
pressure blowers, and the open discharge blast
from vacuum blowers.
• Stayclearoftheblastfrompressurereliefvalves
and the suction area of vacuum relief valves.
• Avoidextendedexposureincloseproximityto
machinery which exceeds safe noise levels.

DVJ WHISPAIR™Dry Exhauster | 13
• Usepropercareandgoodproceduresinhandling,
lifting, installing, operating and maintaining the
equipment.
• Casingpressuremustnotexceed25PSI(172kPa)
gauge. Do not pressurize vented cavities from an
external source, nor restrict the vents.
• 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 warned by signs and trained to exercise
adequate general safety precautions.
Preventive Maintenance
1. Daily
A. Record the following:
1) Lube oil pressure (if applicable).
2) Lube oil temperature (if applicable).
3) Blower inlet temperature.
4) Blower inlet pressure.
5) Blower discharge temperature.
6) Blower discharge pressure or differential pres-
sure.
7) Motor amperage.
8) Motor voltage, if available.
9) Motor stator temperature, if available.
10) Motor bearing temperature, if available.
B. Observe any abnormalities, i.e. burned paint, unusual
noises, vibration, strange odors, oil leaks, etc.
C. Review log sheets to determine if there are any
changes from previous readings. (It is very important
to look for any changes or trends which might indicate
pending problems).
D. Check oil levels.
E. Record hour meter readings.
2. Monthly
A. Record bearing housing vibration levels at each
bearing in the horizontal, vertical, and axial planes. Use
velocity (in./sec.) measurements and note any changes
from previous readings. Take a complete vibration
signature (amplitude versus frequency) if any trends are
noted. (It may be helpful to keep a chart on monthly
readings.)
3. Quarterly
A. Sample lube oil or change.
B. Change oil if the following values are exceeded:
1) Water 100 PPM maximum.
2) Metals 200 PPM maximum.
3) Acid 5.0 to 7.5 Mg/KOH/g maximum.
C. Increase frequency of sampling if any of the above
values show about 20 to 25% increase over the last
sample.
D. Flush all oil reservoirs before filling with clean oil.
4. Annually
A. Remove an inlet expansion joint, inspect impellers,
measure impeller clearances and note wear patterns.
B. Check coupling alignment, inspect coupling for wear,
and repack with fresh grease.
C. Inspect oil cooler tubes, as applicable.
D. Check all protective switches for proper setpoints and
operation.
E. Check V-belt drive condition and tension.
5. A Preventative Maintenance Schedule should be estab-
lished for driver(s) and all accessories in accordance with
the applicable manufacturer’s recommendation.

14 |Dresser Roots
Troubleshooting Checklist
Trouble Item Possible Cause Remedy
No Flow 1
2
3
Speed too low
Wrong Rotation
Obstruction in piping
Check by tachometer and compare with speed on Roots Order Acknowledgment
Compare actual rotation with Figure 4 or 5. Change driver if wrong.
Check piping, screen, valves, silencer, to assure open flow path.
Low Capacity 4
5
6
7
Speed too low
Excessive pressure rise
Obstruction in piping
Excessive slip
See item 1. If belt drive, check for slippage and readjust tension.
Check inlet vacuum and discharge pressure, and compare these figures with
specified operating conditions on order.
See item 3.
Check inside of casing for worn or eroded surfaces causing excessive clearances
Excessive Power 8
9
10
Speed too high
Excessive pressure rise
Impellers rubbing
Check speed and compare with Roots Order Acknowledgement.
See item 3.
Inspect outside of cylinder for high temperature areas, then check for impeller
contact at these points. Look for excessive scale build-up. Correct blower
mounting, drive alignment.
Overheating of
Bearings of Gears
11
12
13
14
15
Inadequate lubrication
Excessive lubrication
Excessive pressure rise
Coupling misalignment
Excessive belt tension
Check oil sump levels in gearhouse and drive end covers.
Check oil levels. If incorrect, drain and refill with oil of recommended grade.
See item 5.
Check carefully. Realign if questionable.
Readjust for correct tension.
Vibration - Refer to
“Rotary Lobe Blower
Vibrations”
16
17
18
19
20
21
Misalignment
Impellers rubbing
Worn bearings/gears
Unbalanced or rubbing
impellers
Driver or blower loose
Piping resonances
See item 14.
See item 10.
Check gear backlash and condition of bearings, and replace as indicated.
Scale or process material may build up on casing and impellers, or inside impel-
lers. Remove build-up to restore original clearances and impeller balance.
Tighten mounting bolts securely.
Determine whether standing wave pressure pulsations are present in the piping.
Refer to Sales Office.

DVJ WHISPAIR™Dry Exhauster | 15
Rotary Lobe Blower Vibrations
The general vibration severity charts derived from Rathbone
vibration severity charts provide guidelines for machines
basically having mass unbalance-turbomachinery, electric
motors, etc. The German specification VDI 2056 - Criteria
for Assessing Mechanical Vibrations of Machines - provides
vibration guide lines for machines with rotating masses
(turbomachinery) and machines having mass effects which
cannot be balanced (reciprocating machines), but does
not specifically address rotary lobe blowers (also known as
ROOTS Blowers) with inherent fluctuating dynamic bearing
loads and torques.
API Standard 619, Rotary Type Positive Displacement
Compressors for General Refinery Services, limits the
vibration level to 0.1 in/sec peak, which is quite ambitious.
Based on experience, practical acceptable vibration levels
lie somewhere between API 619 requirement and VDI 2056
allowance for group D reciprocating machines.
Elements Generating Vibrations in Rotary Lobe Blower:
1. Blower inherent characteristic -
a. Impacting bearing loads excite component/system
natural frequencies.
b. Pressure pulsations set up vibrations at four times the
running speed.
2. Rotary lobe blowers use very close clearances between
the impellers and the housing. The impeller contact will
setup vibrations as follows:
a. Impeller to impeller frontal lobe contact - if contact is
between only one set of lobes, the vibration frequency
will be 1XRPM, if both sets of lobes contact, the
vibration frequency will be 2X RPM.
b. Impeller to cylinder contact - the vibration frequency
will depend on the number of impeller tips contacting
the cylinder which could range from one to four times
the RPM.
c. Impeller to head plate contact - the vibration
frequency will be erratic and unsteady.
3. Damaged gears will generate vibrations at mesh
frequency, number of teeth times RPM.
4. Damaged bearings will generate vibrations at ball pass
frequency, fundamental train frequency and ball spin
frequency.
5. Rotor unbalance and bent shaft will generate vibrations
at 1XRPM.
6. Blower/driver coupling misalignment will generate
vibrations at 1XRPM and 2XRPM.
7. Acoustic resonance in the blower inlet/discharge piping
will generate vibrations at 4XRPM.
8. Operation of rotary lobe blower at or near system tor-
sionals may cause impeller lobe contact and increases
vibrations.
9. External piping if not properly isolated will transmit
vibrations into the blower.
10. Foundation design and method of mounting has
considerable effect on blower vibrations.
Vibration Criteria:
1. Units of measurement: Rotary lobe blower vibrations
are measured in inches/sec. Measurements of spike
energy is not recommended for judging blower condition
because the rotary lobe blower has inherent impacting
bearing loads.
2. Measurement location: Vibrations should be measured
at the bearing locations on the housing.
The following table provides an appropriate assessment
guideline for rotary lobe blowers rigidly mounted on the
stiff foundations.
Unfiltered Vibrations Assessment
(in/sec peak)
>0.62 thru 1.0 Satisfactory
>1.0 Review Required
If the blower is operating at “review required” levels then the
installation must be fully evaluated to determine the source or
cause of vibration and the cause shall be corrected.
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.
The blower vibrations will be transmitted into the motor,
speed reducer etc. and more so if they are mounted on the
common blower baseplate. Allowable vibration levels into
these accessories should be obtained from the vendors.

16 |Dresser Roots
Maintenance/Replacements
A good program of inspection and maintenance servicing, if
followed consistently, is the most reliable means of prevent-
ing costly repairs to a blower. A simple record of procedures
and dates will help maintain this work on a regular schedule.
Basic requirements are lubrication and cleaning, along with
periodic checking for increased vibration and hot spots on
the cylinder. Inlet and discharge pressures and temperatures
should be observed frequently, to minimize the chances for
trouble resulting from blower ratings being exceeded. Above
all, the unit must be operated within its specifications.
In a blower properly installed and operated, there is no
moving contact between the two impellers, or between the
impellers and cylinder or headplates. Wear is then confined
to the timing gears, the bearings which support and locate
the shafts, and shaft seals. All are lubricated, and wear
should be normal if they are always supplied with clean, high
grade lubricating oil. Shaft seals, weather lip type or rotating
mechanical type, are subject to deterioration as well as wear.
They may require replacement at varying periods. O-rings
should be replaced at each disassembly.
If trouble should occur during operation, and its cause cannot
be readily determined, consult the TROUBLESHOOTING
CHECKLIST. Remedies suggested there can usually be
performed by qualified mechanics, using procedures detailed
in this manual. Major repairs not covered here are considered
beyond the scope of maintenance, and should be referred
to the nearest Sales Office. See listing on the last page.
Warranty failures should not be repaired at all, unless
specific approval has been obtained through a Sales Office
before starting the work. Unauthorized disassembly within the
warranty period may void the warranty.
Where repairs involve parts replacement, it is recommended
that Factory Parts be used to insure fit and suitability. Delay
in making such repairs can be reduced by having spare parts
on hand.
When ordering parts, please furnish all information from the
blower nameplate.
Repairs or adjustments to blowers should be performed by
personnel with a good background of general mechanical
experience and the ability to follow the detailed instructions
in this manual. Some operations involve extra care and a
degree of precision work. This is especially true in timing
impellers, and in handling bearings. Experience indicates
that a high percentage of bearing failure is caused by dirt
contamination before or during assembly. Therefore, clean
the work area before starting disassembly, and protect new
or reusable parts during progress of the work.
The following detailed work procedures cover repairs and
adjustments that can normally be handled successfully at the
installation site. Numbers shown in brackets ( ) correspond
to Item Numbers used in the sectional assembly drawings
and in Table 9. Refer to the drawing applying to the type unit
being repaired while reading the instructions.
A - REMOVING GEARS WITH GEAR LOCKING
ASSEMBLIES
1. Drain oil at plug (67) near bottom of gearbox (3).
2. Loosen cap screws (30) attaching gearbox to headplate
3. Attach lifting device to support gearbox and remove
capscrews. Move gearbox out of way.
4. Match mark gears so that they can be returned to the
same shafts in same position.
5. Gradually release gear locking assembly capscrews
evenly all round. Initially each screw should be released
about a quarter of a turn only to prevent tilting and jam-
ming of collars. DO NOT REMOVE LOCKING SCREWS
COMPLETELY OR THE COLLAR MAY SPRING OFF
CAUSING INJURY. Just loosen the locking assembly,
both collars should be loose on the tapered inner rings.
To loosen the back collar, tapping on the locking screws
may be necessary. To loosen the front collar, use of
wedges between the collar and the gear web may be
required
6. Using two puller holes in the gear (see Table 6 for size)
pull the gears off the shafts,
B - INSTALLING GEARS WITH GEAR LOCKING
ASSEMBLIES
1. Apply NEVERSEEZ paste on the gear locking device
screw threads, under the screw heads, on the tapered
rings, on the collar tapers, and on the gear hub outside
diameters.
Figure 6 - Gear Locking Assembly
Table 6 - Puller Hole Sizes
Blower Size Gear Puller Hole Size Carrier Puller Hole Size
1000 1/2/13 5/8/11
1200 3/4/10 5/8/11
1400, 1600 8-Jan 3/4/10
1800, 2000 1-1/4 - 7 8-Jan

DVJ WHISPAIR™Dry Exhauster | 17
2. Slide each tapered ring collar and the web clearance
holes and screw them loosely into the opposite collar.
3. Do not tighten screws at this time.
4. DEGREASE GEAR HUB BORE AND SHAFT. THE
GEARFIT MUST BE FREE OF ANY LUBRICANT.
5. Install two 12" long threaded rods (sizes are give in Table
5) in the bearing carrier puller holes. Line up the gear
puller holes with the rods and using proper nuts on the
guide rods, push the gears on flush with the shaft end.
Make sure that the gear match marks line up. Take any
3 or 4 locking screws equally spaced and snug them up.
6. Set impeller timing as described under Step 4 of
Operation C.
7. Once satisfactory timing is achieved, locking screws
are to be tightened to Table 7 values, using a calibrated
torque wrench. Tighten all locking screws gradually
and all the way around in either clockwise or counter-
clockwise sequence, but not in diametrically opposite
sequence. Tighten screws half a turn at a time. Check
and make sure that no screw will turn any more by
applying specified torque.
10" TAPER BORE GEAR REMOVAL PROCEDURE
1. Remove the gear nut.
2. Install Gear Remover within 1/8th inch of the gear face.
This gap is necessary to unseat gear from the shaft
taper.
3. Apply Neverseez on 3/4-10X3” long, grade 8 capscrew
threads and under hex heads.
4. Install capscrews through gear remover holes into the
gear puller holes.
5. Tighten these capscrews quarter turn at a time in either
clockwise or counter-clockwise sequence, but not
diametrically opposite sequence, till the gear is unseated
from the taper.
6. If the gear does not come off using above method, use
hydraulic assist feature provided in the gear in addition to
the above. Hydraulic pump capable of generating about
20,000 PSI pressure is required. Make sure all tubing
and fittings are good for 40000 PSI. The gear connec-
tions are 1/4 NPT. Hook up pump to bottom connection.
Leave top hole open. Crank the pump till some oil
comes through the open hole bleed¬ing all air out. Close
the top hole with 1/4 NPT solid steel plug. Crank the
pump up till the gear comes off. Do not exceed 20,000
PSI oil pressure. If not sure how to use the hydraulic
removal system, contact factory.
10" TAPER BORE GEAR INSTALLATION PROCEDURE
1. Block the impellers inside the blower using wooden
blocks/wedges.
2. Degrease gear bore and shaft taper. THESE
SURFACES MUST BE FREE OF OIL.
3. Screw the inside ring onto the shaft, snug it up against
the gear by hand.
4. Slide outside ring onto the inside ring.
5. Apply Neverseez on the threads and under the head of
the installation capscrews. Install the capscrews finger
tight.
6. Install indicator on the gear outside face for measuring
the gear axial movement.
Table 7 - Torque Wrench Data
Figure 7 - Taper Gear Remover
Figure 8 - Gear Remover Material - Steel, Hardness - Rc-25
Frame Series
Gear
Capscrew
Size-Metric
Gear
Capscrew
Torque
Values, LB-FT
(kg-M)
Stub Shaft
Screws LB-FT
(kg-M)
1000 M8 (4.2) 30 45 (6)
1200 M8 (4.2) 30 75 (10)
1400 M10 (8.3) 53 75 (10)
1600 M10 (8.3) 60 105 (15)
1800 M12 (13.8) 100 105 (15)
2000 M16 (33.2) 240 250 (35)

18 |Dresser Roots
7. Tighten each screw quarter turn at a time in either
clockwise or counter-clockwise sequence, but not
diametrically opposite sequence, till the outer ring is solid
against the inside ring. THE GEAR SHOULD MOVE
.065 to .075".
8. Loosen up the installation capscrews and remove the
gear installation tooling.
9. Install gear locknut and tighten nut with a spanner
wrench.
C - TIMING THE IMPELLERS
1. Disconnect the piping at both inlet and discharge
flanges of the machine, moving the pipe flanges at least
far enough away for easy insertion of an arm into the
openings.
2. Use a set of feeler gauges with blades about 12” (300
mm) long for measuring clearances between the impeller
lobes. These clearances are identified as “front” and
“backs”, and are measured with the impellers in the
positions shown in Figures 12 and 13. The drive shaft
rotation indicated is counter-clockwise. For opposite
rotation, impeller positions will be reversed from that
shown in Figures 12 and 13 and the front and back iden-
tifications will be interchanged. Fronts may be defined as
the lobes that tend to contact during rotation because
of pressure load and gear tooth wear; conversely, backs
are the surfaces that tend to separate.
3. Determine and record the total lobe clearance by
measuring the front and back clearances and adding
them. It will normally be satisfactory to take these
measurements at the mid-point of the impeller length.
Place a wedge between the gear teeth to prevent the
impellers from shifting during the measurement, making
sure that any gear tooth clearance is always taken up
in the same direction. Note that there are two front
and two back clearance positions in one complete
revolution, use minimum value of clearance found
along length of impeller for fronts and backs
throughout 90° rotation.
4. Loosen the screws on one gear (make sure collars are
loose) to permit slight adjustments of position rela tive
Figure 9 - Taper Gear Installation
Figure 10 - Outside Ring Material,
Steel, Hardness - Rc-25 min
Figure 11 - Inside Ring Material,
Steel, Hardness - Rc-25 min
Figure 12 - Impeller Timing Viewed from
Standard Rotation
Figure 13 - Impeller Timing Viewed from
Standard Rotation

DVJ WHISPAIR™Dry Exhauster | 19
to its impeller, and set the impeller “front” clearance so
that it is two-thirds of the total clearance found in Step 3.
Make sure that any backlash in the gears is taken up in
the direction of rotation with the lower gear driving.
5. Tighten all screws as in Step 7. OPERATION B, and
recheck front and back clearances.
D - REMOVING BEARINGS AND/OR SEALS
1. Dismantle as in Operation A.
2. Remove gear end bearing carriers (6). Bearings and shaft
seals will come out with the carriers. Discard the O-rings
(20). Impellers will now be supported by the labyrinth
seals in headplate holes.
3. Dismount drive and remove drive end cover (5) and/ or
(58), using care with seal (23).
4. Remove bearing locknuts (24) and lockwashers (25),
using a spanner wrench.
5. Remove bearing clamp plates (8).
6. Pull drive end bearing carriers with bearings and seals
as on gear end. Shims (17) under the flanges should
be kept in order and identified for replacing the same
positions.
E - REPLACING LIP SEALS
1. Check shafts for surface finish of 10-16 micro-inch (.3 to
.4 micrometers) RMS in seal contact area, and for good
condition at bearing locations. Carefully remove any
burrs or sharp corners, but do no attempt refinishing.
The seals are “Directional, Hydrodynamic”, which means
for proper sealing they are completely dependent on the
direction of the shaft rotation. In each seal kit, there are:
(2) Clockwise (CW) “Blue coated” seals for inboard seal
replacement
(2) Counter-Clockwise (CCW) “Red coated” seals for inboard
seal replacement
(1) Reversible (CW/CCW) “Green coated” seal for drive shaft
seal replacement
(1) Protective Sleeve Tool (Inboard seals)
(1) Protective Sleeve Tool (Drive shaft seal)
CAUTION: FOR SEALS TO PERFORM PROPERLY
• Usecarefulhandlingproceduressonottodamage
seals during installation. Must use the installation sleeves
provided in kit as shown Under Final Assembly. Seal lips
are not very flexible and will tear or become damaged if
not installed properly.
• Shaftsurfacemustbecleanandfreeofscratcheswitha
finish between 10 to 20 RMS.
• Sealsmuststayonshippingringsuntiltimeofinstalla-
tion, or the seal lips will deform over time.
NOTE: Proper sealing for shafts that have been repaired with
a “speedi-sleeve”. depends on the quality of the “speedi-
sleeve” and its installation.
2. Finish the assembly as outlined in “Final Assembly”.
F - FINAL ASSEMBLY
1. Install all bearings. Making sure they are up tight against
their respective shaft shoulders. Work on gear end
bearings first and press them info place by means of a
suitable length of tubing in contact only with the inner
races. The impellers will be driven against the opposite
headplate. Then remove shims (17) from behind both
drive end bearing carrier flanges and press the bearings
at this end into place against their shaft shoulders.
Seal Installation Guide
Inboard Seal Installation and Drive Shaft Seal Installation

20 |Dresser Roots
On a belt-drive unit with extended shaft, use spacer
sleeve (62) to push inboard bearing (60) into its final
position. There is no shaft shoulder behind this bearing,
but there is a stop for the sleeve. Make sure that the
inner race flange of bearing (60) is facing outboard.
2. Install bearing lockwasher (25) and locknuts (24) on each
shaft, and tighten nuts with a spanner wrench. Lock the
nuts by bending a tab on each washer into a slot in the
nut.
3. Install new or original gears and set impellers as
described in Operation B.
4. Place bearing clamp plate (8) over main bearing (31)
and tighten all screws. In the case of the extended type
drive shaft, end cover (58) serves as the clamp plate but
cannot be installed until later.
5. Using 1/2” (13mm) feeler gauges, determine for each
of the drive end bearings (31) the maximum clearance
between the outer race and one of the rollers near the
top. Obtain pieces of brass shim stock, of thicknesses
corresponding to these clearances, about 3/4” (19mm)
wide and long enough to reach completely through the
bearings. Push one piece through each bearing, in the
spaces between rollers, then rotate that shaft so that one
roller of each row is up on the shim stock. This removes
all clearances, and forces the bearing rollers and races to
center as in normal running. Refer to Figure 14.
6. Set the impellers lengthwise in the case by using long
pieces of shim stock, or feelers, as wedges between the
two ends of each impeller and the headplates. Using the
total end clearance obtained in Step 8 of Operation D,
the two ends of each impeller and the headplates. Using
the total end clearance obtained in Step 8 of Operation
D, place wedges equal to two-thirds of the total at the
gear end and one-third at the drive or thrust end. It will
be necessary to bump the shafts to obtain the required
impeller positions. Set the drive end clearance first, after
installing and tightening drive shaft end cover (58) if used.
7. With feeler gauges, carefully measure the spaces
between the drive end bearing carrier flanges and the
headplate face. Insert shims (17) of correct thickness to
fill these spaces. The original shims should be correct if
bearings and carriers have been returned to the original
location.
8. Remove wedges from ends of impellers inside the casing.
9. Tighten all bearing carrier flange screws.
10. Recheck impeller end clearances for proper values
per tables, then remove brass shim stock from both
bearings (31).
11. Check front and back clearances of impeller lobes as
outlined in Operation C, and reset timing if not correct.
12. Reassemble the unit, starting by installing the main end
cover (5) and then proceeding in reverse order through
Operation A from Step 5. Be careful with lip seal (23) or
new O-ring (59) in end cover (5).
13. Check the work area to make sure no parts have been
left out in assembly.
14. Turn the drive shaft over several times by hand as final
check for impeller contact or case rubs.
15. Reinstall coupling or belt sheave, check their alignment
with driver and reconnect all external piping.
16. Start and operate unit for a reasonable period in the
manner outlined for initial starting. See OPERATION.
IMPELLER CLEARANCES
Instructions on impeller clearances under Operation C and
Operation D do not include data on the amount of clearance
to be expected. For blowers in good condition this informa-
tion is not essential in field service work. However, situations
may arise where it is desirable to compare existing clearances
with the correct values. Listed in Table 8 or 9 are the ranges
of values used in original factory assembly. Clearances may
change in service, but they should never be less than the
minimum values listed. Only well qualified personnel should
attempt to measure clearances for comparison with this data.
Figure 14

DVJ WHISPAIR™Dry Exhauster | 21
Repair Kit Information For DVJ WHISPAIR™Dry Exhausters
Repair Kit Part Numbers
REF. QTY. PART DESCRIPTION
17 1 SHIM SET
18 1 GASKET
19 2 GASKET SUMP (P/L)
20 4 O-RING B/C (PL)
23 1 SEAL-DR. SHAFT
24 2 LOCKNUT-BRG.
25 2 LOCKWASHER-BRG.
27 4 SEAL-HDPLT
31 4 BEARINGS
60 1 BEARINGS*
61 2 O-RING
81 2 GASKETS
- 1 Set GEAR SCREWS**
*V-Belt kits only **12" kits and above
SIZE REPAIR KIT NOS.
(CPLG DRIVE)
REPAIR KIT NO.
(V-BELT DRIVE)
10" RK10ACP00 RK10AVB00
12" RK12ACP00 RK12AVB00
14" RK14ACP00 RK14AVB00
16" RK16ACP00
18" RK18ACP00
20" RK20ACP00
WHEN ORDERING CONTACT:
Dresser Roots
900 West Mount Street
Connersville, IN 47331-1675
Phone: [phone]
Rapifax: 765-827-9309