RXF ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
070.410-IOM (JAN 12)
Page 28
15. Pack the double row ball bearing with multi-purpose
grease, NLGI #2.
GG, HJ, HL: Install the ball bearing into the bearing housing
with shield side toward the coupling end of the shaft. See
Figure 29. Install the snap ring into bearing housing to retain
ball bearing. This snap ring has a tapered edge to t tapered
groove in bearing housing. The tapered edge is located away
from the ball bearing.
AS, AK, AL: Install the ball bearing into the bearing housing.
Install the lip seal in the bearing housing end cap. The lip
should face towards the end of the shaft. Put the bearing
spacer collar in the lip seal and install in the bearing housing
and tighten the set screws securely. See Figure 30.
16. Insert a brass bar or piece of hardwood through the
port opening between the rotor teeth to keep the shaft
from turning.
17. Start the thrust bearing assembly into casing. Turn by hand
until tight. This forces the rotor against the head. Replace
and tighten the locknut or shaft.
18. Remove the brass bar or hardwood from port opening.
19. Adjust pump end clearance, refer to “Thrust Bearing
Adjustment”.
BEFORE STARTING PUMP, ENSURE
THAT ALL DRIVE EQUIPMENT
GUARDS ARE IN PLACE. FAILURE TO
PROPERLY MOUNT GUARDS MAY RESULT IN SERIOUS
INJURY OR DEATH.
THRUST BEARING ADJUSTMENT
Loosen two screws in face of thrust-bearing assembly. See
Figures 29 and 30.
If shaft cannot be rotated freely, turn thrust-bearing assembly
counterclockwise until shaft can be turned easily.
1. While turning rotor shaft, rotate thrust-bearing assembly
clockwise until noticeable drag occurs. This is zero end
clearance.
2. Mark position of bearing housing with respect to the casing.
3. Rotate thrust-bearing assembly counterclockwise the
dis tance listed below as measured on outside of bearing
hous ing.
4. Tighten two setscrews in face of bearing housing after
adjust ment is made to secure thrust-bearing assembly
position.
For viscosities above 2500 SSU, add additional end clearance
(0.004" for GG, HJ and HL size pumps and 0.005" for AS,
AK and AL size pumps).
GG 7/16 .003
HJ, HL 9/16 .003
AS, AK, AL 1/2 .003
INSTALLATION OF
CARBON GRAPHITE BUSHINGS
When installing carbon graphite bushings, extreme care must
be taken to prevent breaking. Carbon graphite is a brittle
material and easily cracked. If cracked, the bushing will
quickly disinte grate. Using a lubricant and adding a chamfer
on the bushing and the mating part will help in installation.
The additional precautions listed below must be followed
for proper installation:
1. A press must be used for installation.
2. Be certain bushing is started straight.
3. Do not stop pressing operation until bushing is in proper
position. Starting and stopping will result in a cracked bush-
ing.
4. Check bushing for cracks after installation.
TROUBLESHOOTING THE DEMAND PUMP
BEFORE OPENING ANY PUMP LIQUID
CHAMBER (PUMPING CHAMBER,
RESERVOIR, JACKET ETC.) ENSURE:
1. THAT ANY PRESSURE IN CHAMBER HAS BEEN COM-
PLETELY VENTED THROUGH SUCTION OR DISCHARGE
LINES OR OTHER APPROPRIATE OPENINGS OR CONNEC-
TIONS.
2. THAT THE DRIVING MEANS (MOTOR, TURBINE, EN-
GINE, ETC.) HAS BEEN “LOCKED OUT” OR MADE NON-
OPERATIONAL SO THAT IT CANNOT BE STARTED WHILE
WORK IS BEING DONE ON PUMP.
FAILURE TO FOLLOW ABOVE LISTED PRECAUTIONARY
MEASURES MAY RESULT IN SERIOUS INJURY OR DEATH.
Mark valve and head before disassembly to ensure proper
reassembly.
If trouble does develop, one of the rst steps toward nd-
ing the difculty is to install a vacuum gauge in the suction
port and a pressure gauge in the discharge port. Readings
on these gauges often will give a clue as to where to start
looking for the trouble.
Vacuum Gauge—Suction Port
1. High reading would indicate:
a. Suction line blocked - foot valve stuck, gate valve
closed, strainer plugged.
b. Liquid too viscous to ow through the piping.
c. Lift too high.
d. Line too small.
2. Low reading would indicate -
a. Air leak in suction line.
b. End of pipe not in liquid.
c. Pump is worn.
d. Pump is dry - should be primed.
3. Fluttering, jumping, or erratic reading:
a. Liquid vaporizing.
b. Liquid coming to pump in slugs - possibly an air leak
or insufcient liquid above the end of the suction pipe.
c. Vibrating from cavitation, misalignment, or damaged
parts.
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