INSTALLATION, OPERATION & MAINTENANCE MANUAL PRVS Centrifugal Fiberglass Blower Bulletin 25-02-February 2017
M.K. Plastics Corp. Montréal, Québec, Canada +1-514-871-9999 www.mkplastics.com Page 7 of 12
PRVS blowers that are Direct Drive Arrangement 4 are
supplied with a motor shaft that is drilled and tapped to
accommodate the blower shaft. Contact M.K. Plastics if a
motor replacement is ever necessary.
Should the motor prove defective within a one-year period,
contact M.K. Plastics directly, or you may contact your
nearest motor service representative.
Wheel and Shaft Maintenance
Periodically inspect the shaft and wheel for dirt buildup,
corrosion, and signs of excess stress or fatigue. The wheel
can be inspected via the view port. Clean the components
as necessary. If the wheel is removed for any reason,
make sure that it is securely attached to the shaft before
restarting the blower.
Drainage Detail
All PRVS blowers come with outlet drains due to water or
condensation that may accumulate. Proper disposal of the
water is necessary. Connect the drain outlet to a drainage
system (by others.)
Blower Bearings
All PRVS blowers are equipped with solid pillow block
bearings. They are equipped with an integral set screw
lock.
Blower Bearing Lubrication:
All PRVS Blowers use only Self-Lube pillow block bearings.
Bearings are factory charged with the correct amount of
grease and do not require further grease charge.
Re-lubrication is not required. See Figure 19.
Figure 19
Solid Pillow Block Bearing
Note: The motor bearing lubrication should be per the
motor manufacturer’s instructions.
Blower Bearing Replacement:
Blower bearing replacement intervals are defined by the
blower operator. M.K. Plastics does not define a schedule
for bearing replacement, as it is dependent on the
environment, usage and maintenance of each specific
blower installation. With proper installation, operation and
maintenance however, PRVS bearings should last several
years. All PRVS blowers are equipped with NSK, RHP
Self-Lube cast iron pillow block units, NP or MP series.
Indicators that bearings need replacement include
excessive noise, vibration or heat in the vicinity of the
bearings.
In applications where contact with the exhaust poses a
serious contamination factor, the bearings can be removed
without removing the wheel and inlet cone. In this case, the
shaft must be held in place with suitable straps or bracings
firmly secured around the bearing support frame. The shaft
must be supported to restrict any lateral movement of both
the shaft and impeller.
Removal of Wheel, Shaft & Bearings:
1. Take note or make a sketch of the position on the
shaft of both bearing races, setscrews and the
wheel and sheave. If you are replacing the shaft
as well, these notes or sketch will give you
reference.
2. Mark the location and orientation of the inlet to
the casing and remove. Note the clearance
between the wheel and the inlet cone. This will
give you access to the wheel.
3. Remove the drive sheave from the shaft.
4. Start wheel removal by unscrewing the front
protective cap and then the nut, washers and
threaded stud assembly that holds the cap to the
blower shaft. Unscrew the setscrews in the wheel
hub. The wheel can now be removed from the
blower shaft. PRVS blowers do not have
bushings, the wheel is held in place on the shaft
with the threaded rod assembly, 2 setscrews on
the wheel hub and key.
5. Remove the bearing housing mounting bolts and
remove the shaft and bearings as one unit. Keep
any existing shims in place.
6. The bearings are attached with set screws;
unscrew and slide the assembly off as one piece.
Tap on the bearing with a wood block and hammer
to remove if necessary.
7. If the existing shaft is being used, check the
shaft for nicks, burrs and damage. Remove any
anti-corrosion coating with a suitable degreaser
and wipe clean.
Bearing Replacement:
1. Making sure that the setscrews are not protruding
from the inner bearing rings, slide the bearings
directly onto the shaft. If using an old shaft, make
sure the bearings are not mounted on a worn
section. Tapping the inner ring face with a soft
driver might be required. Do not hammer on the
housing.
2. The outer ring of the bearing is spherical and
swivels in the housing to compensate for
misalignment. Secure the housing to the stand
with the fixing bolts, but do not fully tighten.
3. Install the wheel on the shaft, and block it in place.
Install the inlet in its original location. Position the
wheel correctly by moving the shaft axially in the
bearing assemblies.
4. Tighten the setscrews on the bearings to
secure the shaft. Refer to torque chart in Figure
20.
5. Rotate the shaft by hand to allow the bearing outer
rings to find their center of free movement.
