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Service
2. Remove the suction end journal bearing (See Re-
moving Suction End Journal Bearing).
Check the as-built prints carefully. If the
compressor has suction end proximity
probes, the special sleeve must be in-
stalled in place of the shaft bearing to
protect the probes during removal of the
bearing housing. If sleeves and man-
drels are not available at site contact the
nearest YORK office for replacements.
3. Remove the oil tubing and seal gas lines from
the bearing housing and seal them to prevent
contamination.
4. Remove the cap screws that hold the bearing hous-
ing (15) on the PRV housing. (Refer to Fig. 19).
5. Install the guide pins to hold the housing in place
when it is loosened. Use cap screws as jack bolts.
Remove the housing (15) and PRV sleeve gaskets
(22, 23, 24). Record thickness and number removed.
6. A-1 seal removal and replacement.
A. Pull the PRV sleeve housing carefully over
the shaft. Use suitable threaded rod as jack
screws to pull out and hold the sleeve. Place
the housing with the small end down on a
bench or board. Remove the inboard sleeve
gaskets (22, 23, 24). Record number and
thicknesses removed.
B. Use snap ring pliers to remove the retaining
ring (20) and then remove the universal spring
(21) from the PRV sleeve housing.
C. Pull the seal ring from the sleeve housing.
Older units used variable sleeve gas-
kets to establish a set squealer clear-
ance between the compressor rotor
and PRV sleeve. On these units the
PRV sleeve housing extends beyond
the inner end of the seal ring. Thrust
bearing wear or high superheat may
allow the rotor to contact the sleeve
housing. Particles rubbed off during
contact will erode the oil seal, caus-
ing oil loss during operation. Carefully
examine the PRV sleeve housing and
rotor shoulder for evidence of rubbing.
44
D. Examine the seal ring flange and PRV housing
mating surface for evidence of wear or scoring
(use bluing if necessary). The inboard surface
of the seal flange must sit flat within the PRV
sleeve recess. The oil seal is a stationary seal.
If it rotates you should see evidence of it. Just a
slight deviation from a flat seal can promote oil
loss, Inspect the ID of the seal ring for erosion.
Dirt from the pressuring stage can erode a seal,
resulting in oil loss.
To install the new seal ring assembly and gaskets.
A. Assemble a new seal ring (19), universal
spring (21) and snap ring (20) into the PRV
sleeve housing. If the seal ring is excessively
loose use a second universal spring to tighten
the seal ring. The seal ring must be able to
move with some minimal radial force.
B. Install the inboard PRV sleeve gaskets (22,
23 or 24).
C. Lubricate the ID of the seal ring and the rotor
shaft with Molycote and oil.
D. Assemble the PRV sleeve housing into the
PRV housing. On large machines (38 and 55
inches) the sleeve is a heavy item, be careful
as you slide it over the compressor shaft. Af-
ter the seal is started over the rotor shaft,
screw the drive shaft into the rotor a couple
of turns and lift the rotor as you slide the
sleeve in to it's full depth.
E. Install new gaskets (22, 23 or 24), same num-
ber and thickness as you removed, otherwise
the axial rotor clearances and seal deck will
be changed.
F.
Install bearing housing, see step 9 on page 45.
The A-4 seal is a dual spring tensioned
seal. Individual rings are occasionally
different lengths. Check the rings
carefully to ensure they are replaced
in the proper position.
7. A-4 seal removal and replacement.
A. After protecting the rotor shaft, use pulling
rods to remove the A-4 seal sleeve. Note the
full bodied gasket and alignment roll pin.
There is a specific location for the buffer gas
flow to pass through the gasket.
FORM 220.11-NM2 (602)
YORK INTERNATIONAL
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