Figure 4.5B: Packing adjusting screws
4.6 Cylinder Replacement
Cylinders very seldom require replacement if the
compressor is properly maintained. The primary cause
of damage to cylinders is corrosion and the entry of solid
debris or liquid into the compression chamber. Improper
storage can also result in corrosion damage to the
cylinder (for proper storage instructions see chapter 5).
If the cylinder is damaged or corroded, use a hone
to smooth the cylinder bore and then polish it to the
value shown in Appendix B. If more than .005 of an
inch must be removed to smooth the bore, replace
the cylinder. Cylinder liners and oversized rings are
not available. OVERBORING THE CYLINDER WILL
RESULT IN GREATLY REDUCED PISTON RING LIFE.
Many compressor repair operations require removal of the
cylinder. While the compressor is disassembled, special
care should be taken to avoid damage or corrosion to
the cylinder. If the compressor is to be left open for more
than a few hours, bare metal surfaces should be coated
with rust preventative.
When reassembling the compressor, make sure the
bolts are retightened using the torque values listed in
Appendix B.
4.6.1 Cylinder Installation and Alignment
Piston must not touch cylinder! To check this clearance,
assembly personnel will need to check clearance with
feeler gauges.
1. Place the cylinder on the crosshead guide and start
installing the bolts. Do not tighten them all the way. At
this step, the cylinder must remain loose.
2. Attach the piston head to the piston platform in each
stage using the sockethead screws. Tighten the
sockethead screws using the torque specification
listed in Appendix B.
3. To properly align the cylinder, rotate the crankshaft
all the way through the stroke. MAKE CERTAIN
BOTH PISTONS ARE CENTERED ALL THE WAY
THROUGH THE STROKE by adjusting the position
of the cylinder as necessary. The pistons must not
touch the cylinder wall.
4. After the cylinder is properly aligned to the pistons,
tighten the bolts using the torque specification listed
in Appendix B. Start in the center and work outward.
5. Rotate the crank one more time and make sure the
pistons do not bind against the cylinder wall.
6. If there is interference, repeat steps 1-6 until
clearance is obtained. When the proper clearance
has been obtained, re-torque bolts using the torque
specifications listed in Appendix B.
4.6.2 Packing Replacement
Caution: Before installing the new piston rod packing, bleed
all pressure from the compressor and piping and purge
if necessary. After the new piston rod packing has been
installed, the unit should be pressure tested and checked
for leaks at all joints and gasket surfaces. When the
compressor is being used with toxic, dangerous, flammable
or explosive gases, this pressure and leak testing should be
done with air or a dry, inert gas such as nitrogen.
For simplicity, the compressor head, pistons, and
inspection plate are not shown. For specific construction
details and actual part numbers, consult Appendix E in
the back of this Installation, Operation & Maintenance
(IOM) manual. Use instructions below that apply to the
MODEL and SERIAL NUMBER of your compressor.
BE CAREFUL TO ARRANGE PACKING SETS IN THE
PROPER ORDER.
Cleanliness:
Sealing a reciprocating piston rod is a very difficult
task. Keep all parts, tools and your hands clean during
installation. Your new packing needs every chance it can
get, so keep it clean.
Workmanship:
Your Corken compressor is a precision piece of equipment
with very close tolerances. Treat it as such. Never beat
on it to get parts in or out.
Packing Configuration
The packing for these compressors includes V-ring
packing in a packing cartridge on each piston rod.
Refer to Appendix E for packing assembly details. Note
the arrangement of the particular packing sets for the
model of machine that you have.
Disassembly of Packing
1. Depressurize and open the compressor.
16
