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BLOWER LUBRICATION – MINI-PRO
A simple but very effective lubrication system is employed on UNIVERSAL RAI blowers. At the
drive shaft end the bearings are grease lubricated using hydraulic pressure relief fittings. These
relief fittings vent any excess grease, preventing pressure build-up on the seals. A restriction plug
and metering orifice prevent loss of lubricant from initial surges in lubricant pressure but permit
venting excess lubricant under steadily rising pressures.
The blind end bearings and timing gears are enclosed by a gearhouse located opposite the drive
end of the blower. In a side outlet blower, the lower timing gear functions as an oil slinger,
carrying lubricant to the upper timing gear and providing splash lubrication for the bearings.
Pressure within the gearbox is vented through the breather vent plug.
Before starting blower
, be sure oil has been put in gearhouse. For recommended lubrication oil
see Table below. Use a good grade industrial type rust, oxidation, and foam inhibited, non-
detergent oil such as Mobil DTE BB, Texaco R&O 220,Amoco 220 or equal. Also, Roots synthetic
oil has proven to be an excellent lubricant.
Recommended Oil Grades (Gear Oil)
Ambient
Viscosity Range
ISO No
Approximate
Temperature °F (°C)
SSU at 100° F(38 °C)
SAE No
Above 90° (32°C)
1000-1200
320
60
32° to 90° (0° to 32°)
700-1000
220
50
0° to 32° (-18° to 0°)
500-700
150
40
Below 0° (-18°)
300-500
100
30
To fill the gearbox, remove the breather plug and the oil overflow plug (see diagram). Fill the
reservoir up to the overflow hole. Place the breather and the overflow plug back into their
respective holes.
Frame Size 24: Capacity, 3.4 Oz. (.1 Liters)
Proper lubrication is usually the most important single consideration in obtaining maximum
service life and the most satisfactory operation from the unit. Unless operating conditions are
quite severe, a weekly check of gearhouse oil level and necessary addition of lubricant should be
sufficient. However, oil should be changed after initial 100 hours
Of operation. Thereafter, a complete oil change normally is made after 1000 operating hours, or
less, depending on the type oil and oil operating temperature.
Shaft bearings at the drive end of the blower are grease lubricated and each
bearing housing is equipped with pressure type grease fittings and pressure type relief fittings.
When servicing drive end bearings, use a NLGI #2 premium grade, petroleum base grease with
high temperature (300° service temperature) and moisture resistance and good mechanical
stability. Using a pressure gun, force new lubricant into each drive end bearing housing until
traces of clean grease comes out of the relief fitting.
After a long shutdown, it is recommended that the grease relief fittings be removed, the
old grease flushed out with kerosene or #10 lubricating oil, drained thoroughly, and bearings
refilled with new grease. Be sure grease relief fittings are reinstalled. Grease should be added
using hand operated grease gun to the drive end bearings at varying time intervals depending on
duty cycle and RPM. Information has been prepared as a general greasing schedule guide based
on average operating conditions. More frequent intervals may be necessary depending on the
grease operating temperature and under unusual circumstances.
Suggested Bearing Lubrication Intervals
Speed
Operating Hours Day
In
8
16
24
RPM
Greasing Intervals in Weeks
1500-2000
4
2
1
2000-2500
3
1
1
2500-3000
2
1
1
18