Corken HG601 Series Instruction manual

Installation, Operation
& Maintenance Manual
Plain & T-Style Double-Acting Gas Compressors
Models HG601, HG602, THG601 & THG602 Series
ORIGINAL INSTRUCTIONS IJ100F
Warning: (1) Periodic inspection and maintenance of Corken products is essential. (2) Inspection, maintenance and installation of
Corken products must be made only by experienced, trained and qualified personnel. (3) Maintenance, use and installation of Corken
products must comply with Corken instructions, applicable laws and safety standards. (4) Transfer of toxic, dangerous, flammable or
explosive substances using Corken products is at user’s risk and equipment should be operated only by qualified personnel according
to applicable laws and safety standards.
Model HG601EE
(Plain style)
Model THG602BE
(T-style)
Solutions beyond products...

Warning
Install, use and maintain this equipment according to Corken’s instructions and all applicable federal, state, local laws
and codes. Periodic inspection and maintenance is essential.
Corken One Year Warranty
CORKEN, INC. warrants that its products will be free from defects in material and workmanship for a period of
one year from date of installation, provided that the warranty shall not extend beyond twenty-four (24) months from
the date of shipment from CORKEN. If a warranty dispute occurs, the DISTRIBUTOR may be required to provide
CORKEN with proof of date of sale. The minimum requirement would be a copy of the DISTRIBUTOR’S invoice to
the customer.
CORKEN products which fail within the warrant period due to defects in material or workmanship will be repaired
or replaced at CORKEN’s option, when returned, freight prepaid to CORKEN, INC., 9201 North I-35 Service Road,
Oklahoma City, OK. 73131.
Parts subject to wear or abuse, such as mechanical seals, blades, piston rings, valves and packing, and other parts
showing signs of abuse, neglect or failure to be properly maintained are not covered by this limited warranty. Also,
equipment, parts and accessories not manufactured by CORKEN but furnished with CORKEN products are not
covered by this limited warranty and the purchaser must look to the original manufacturer’s warranty, if any. This
limited warranty is void if the CORKEN product has been altered or repaired without the consent of CORKEN.
All implied warranties, including any implied warranty of merchantability or fitness for a particular purpose, are
expressly negated to the extent permitted by law and shall in no event extend beyond the expressed warranty period.
CORKEN DISCLAIMS ANY LIABILITY FOR CONSEQUENTIAL DAMAGES DUE TO BREACH OF ANY WRITTEN OR
IMPLIED WARRANTY ON CORKEN PRODUCTS. Transfer of toxic, dangerous, flammable or explosive substances
using CORKEN products is at the user’s risk. Experienced, trained personnel in compliance with governmental and
industrial safety standards should handle such substances.
Important notes relating to the European Union (EU) Machinery Directive
Compressors delivered without electric motors are not considered as machines in the EU Machinery Directive. These
compressors will be delivered with a Declaration of Incorporation. The fabricator of the machinery must assure and
declare full compliance with this Directive before the machine in which the compressor will be incorporated, or of
which it is a part, is put into service.
Contacting the Factory
Before contacting the factory, note the model and serial numbers. The serial number directs Corken personnel to a
file containing all information on material specifications and test data applying to the product. When ordering parts,
the Corken service manual or Installation, Operations, and Maintenance (IOM) manual should be consulted for the
proper part numbers. ALWAYS INCLUDE THE MODEL NUMBER AND SERIAL NUMBER WHEN ORDERING PARTS.
The model and serial numbers are shown on the nameplate of the unit. Record this information for future reference.
Model No.
Serial No.
Date Purchased
Date Installed
Purchased From
Installed By
2

Table of Contents
Chapter 1—Introduction........................................................................4
Chapter 2—Installation of the Compressor........................................................6
2.1 Location .................................................................................6
2.2 Foundation ...............................................................................6
2.3 Piping ...................................................................................6
2.4 Liquid Trap ...............................................................................7
2.5 Driver Installation and Flywheels ..............................................................8
2.6 Crankcase Lubrication......................................................................8
2.7 Relief Valves .............................................................................12
2.8 Shutdown/Alarm Devices...................................................................12
Chapter 3—Starting Up the Compressor.........................................................13
3.1 Inspection After Extended Storage ...........................................................13
3.2 Flywheel and V-belt Alignment ..............................................................13
3.3 Crankcase Oil Pressure Adjustment ..........................................................14
3.4 Compressor Speed and Rotation Direction ....................................................15
3.5 Compressor Cooling ......................................................................15
3.6 Force Feed Cylinder Lubrication (Lubed models only) ............................................15
3.7 Variable Clearance Heads (VCH) .............................................................16
3.8 Startup Check List ........................................................................16
Chapter 4—Routine Maintenance Chart .........................................................17
Chapter 5—Routine Service and Repair Procedures...............................................17
5.1 Compressor Valves .......................................................................17
5.2 Heads..................................................................................18
5.3 Piston Rings and Piston Ring Expander Replacement ............................................19
5.4 Pistons .................................................................................19
5.5 Cylinder Replacement .....................................................................20
5.6 Packing Replacement Instructions ...........................................................20
5.7 Bearing Replacement for Crankcase and Connecting Rod ........................................26
5.8 Oil Pump Inspection ......................................................................29
5.9 Disposal ................................................................................29
Chapter 6—Extended Storage Procedures .......................................................29
6.1 Repair Kits ..............................................................................29
6.2 Gasket Sets .............................................................................30
Chapter 7—Safety ............................................................................31
Appendices
A. Model Number Identification Code and Available Options..........................................34
B. Specifications ............................................................................41
C. Outline Dimensions ........................................................................47
D. Parts Details .............................................................................51
E. Troubleshooting ...........................................................................85
3

Placement of valves:
Make inspection and
maintenance simple.
Flywheel
Crankcase
nameplate
Lifting eye
Self-lubricating piston and rider rings:
Made of PTFE to ensure extended service life
Cylinder
nameplate
Packing cartridge body:
Holds the outer and
middle sets of packing.
Packing cartridge adaptor:
Holds the inner oil wiper
ring set and inner packing
Adapter
Oil lter
(Optional)
Oil divider valve assembly:
Ensures each cylinder has the
same amount of lubrication.
Distance piece:
Ensures greater leakage control
Crankcase
inspection plate
Crankshaft journal, connecting rod
bearings, wrist pins, and crossheads:
Pressure lubricated by an oil pump with oil
ltered by a 10-micron spin on lter.
1/4"Pipe plug
Outer packing set
Middle packing set
Outer distance piece
(Barrier 2)
Inner distance piece
(Barrier 1)
Oil deector ring
Inner oil wiper ring set
Inner packing set
Heavy-duty crankcase:
A rugged, internally ribbed design,
incorporating heavy-duty main bearings
and four-bolt connecting rods
Variable clearance head:
Allows changing
the capacity and
BHP requirements.
(Optional) Force-feed lubricator:
Assures proper lubrication of
cylinders and packing when required
Heavy-duty cylinder design:
Each cylinder is hydrostatically tested to 1-1/2
times the rated working pressure for maximum
strength. A corrosion resistant coating (MC1002)
is available for all cylinder sizes. MC1002 extends
the life of the cylinder and piston rings.
(Optional) Thermostatically
controlled crankcase heater:
Assures proper oil viscosity
throughout all weather
conditions.
Why Corken
Compressors are Special
Corken industrial gas compressors are unique among
compressors their size. Unlike ordinary lubricated gas
compressors, Corken compressors completely isolate
the pressurized gas in the compression chamber from
the crankcase. While piston rings seal the piston tightly
enough for it to do compression work, they do not provide
enough sealing to isolate the compression chamber from
the crankcase. To further seal the compression chamber,
a crosshead/piston rod design with seals around the
piston rod is required.
By utilizing specialized piston-rod sealing systems,
Corken compressors can compress pressurized,
flammable, and toxic gases. They can also be used to
compress harmless gases where oil-free compression
or elevated suction pressures are required. With a large
selection of design options available, Corken offers the
most versatile line of small gas compressors in the world.
Corken Horizontal
Gas Compressors
Corken's horizontal compressor is a double-acting
reciprocating compressor; however, when an optional blank
valve is used, the compressor is single acting. Corken
horizontal compressors have a large number of configurations
to fit individual requirements. They are manufactured as
single stage- or two-stage units. For more information on the
various configurations, refer to Appendix A.
Chapter 1—Introduction
4

Placement of valves:
Make inspection and
maintenance simple.
Flywheel
Crankcase
nameplate
Lifting eye
Self-lubricating piston and rider rings:
Made of PTFE to ensure extended service life
Cylinder
nameplate
Packing cartridge body:
Holds the outer and
middle sets of packing.
Packing cartridge adaptor:
Holds the inner oil wiper
ring set and inner packing
Adapter
Oil lter
(Optional)
Oil divider valve assembly:
Ensures each cylinder has the
same amount of lubrication.
Distance piece:
Ensures greater leakage control
Crankcase
inspection plate
Crankshaft journal, connecting rod
bearings, wrist pins, and crossheads:
Pressure lubricated by an oil pump with oil
ltered by a 10-micron spin on lter.
1/4"Pipe plug
Outer packing set
Middle packing set
Outer distance piece
(Barrier 2)
Inner distance piece
(Barrier 1)
Oil deector ring
Inner oil wiper ring set
Inner packing set
Heavy-duty crankcase:
A rugged, internally ribbed design,
incorporating heavy-duty main bearings
and four-bolt connecting rods
Variable clearance head:
Allows changing
the capacity and
BHP requirements.
(Optional) Force-feed lubricator:
Assures proper lubrication of
cylinders and packing when required
Heavy-duty cylinder design:
Each cylinder is hydrostatically tested to 1-1/2
times the rated working pressure for maximum
strength. A corrosion resistant coating (MC1002)
is available for all cylinder sizes. MC1002 extends
the life of the cylinder and piston rings.
(Optional) Thermostatically
controlled crankcase heater:
Assures proper oil viscosity
throughout all weather
conditions.
5

2.1 Location
NOTE: Compressor must be installed in a well
ventilated area.
Corken compressors are designed and manufactured for
outdoor duty. For applications where the compressor will
be subjected to extreme conditions for extended periods
such as corrosive environments, arctic conditions, etc.,
consult Corken. Check local safety regulations and building
codes to assure installation will meet local safety standards.
Corken compressors handling toxic or flammable gases
should be located outdoors. A minimum of 18 inches
(457.2 mm) clearance between the compressor and the
nearest wall is advised to make it accessible from all sides
and to provide unrestricted air flow for adequate cooling.
Noise:
Corken Horizontal compressors should not exceed an 85
DBA noise level at a distance of one meter (3.3 ft.) when
properly installed.
2.2 Foundation
The foundation design is the end user’s responsibility.
Local soil conditions can affect the foundation design.
Generally speaking, the larger the foundation, vibration
or shaking problems are less likely. As a rule of thumb,
when preparing the foundation, the mounting slab
should be 8 to 10 inches thick with the overall length
and width 4 inches longer and wider on each side of the
structural skid.
Grouting the skid helps reduce vibration. An un-grouted
skid flexes and allows the compressor to vibrate.
Secure the skid with 3/4-inch diameter “J” type anchor
bolts embedded in the concrete. Use a sufficient length
and strength and do not skip any holes on the skid.
Expansion bolts and All-thread should never be used.
All anchor bolts should be tightened on a routine basis.
NOTE: Be sure to use all anchor holes on the skid.
2.3 Piping
Piping design and installation is as important as the
foundation for trouble-free compressor operation.
Improper piping installation will result in undesirable
compressor vibration transmission through the piping to
other parts of the installation.
DO NOT SUPPORT PIPING WITH THE COMPRESSOR.
The compressor must not support any significant piping
weight; therefore, the piping must be fully supported. The
use of flexible connections to the compressor is highly
recommended. Rigid, unsupported piping combined
with a poor foundation will result in severe vibration. In
order to reduce vibration in the piping induced by the
compressor, flex hoses may be installed at the inlet
and outlet. These should be oriented vertically and
not horizontally. Vibration can also be caused by the
pulsating flow of gas inside the pipes.
The pulsating flow is normal and to be expected from
a piston type compressor. If this is a problem, it can
generally be corrected with pipe supports or pulsation
dampeners. In Corken’s size range, generally, a small
vessel in the piping is all that is required to act as a
pulsation dampener. The rule of thumb to size a pulsation
dampener is the volume must be at least ten times the
swept cylinder volume. Please note that this calculation
may vary depending on the application.
Pipe must be adequately sized to prevent excessive pressure
drop between the suction source and the compressor as
well as between the compressor and the final discharge
point. In most cases, piping should be at least the same
diameter as the suction nozzle on the compressor.
Install a strainer at the compressor inlet to reduce the
amount of foreign particles in the gas stream. These can
shorten the effective life of valves, piston rings, cylinder, etc.
Never install a shut-off valve in the discharge piping
unless a safety relief valve is placed in the line between
the shut-off valve and the compressor. Remember to
consider future expansion when sizing piping and layout.
If a restrictive device such as an isolation valve or check
valve is to be installed in the compressor’s suction line,
care must be taken. The suction line volume between
Chapter 2—Installation of the Compressor
Figure 2.2
Main beam (C-beam or W-beam)
Cross beam (H-beam)
3/4" diameter “J” bolt
Hex nut
and washer
Concrete foundation
Ground level
Note: The depth of the concrete foundation will
vary based on local soil conditions.
6

the restrictive device and the compressor suction nozzle
must be at least ten times the swept cylinder volume.
On liquefied gas applications such as LPG, it is of
extreme importance to prevent the entry of liquid into the
compressor. Installing a liquid trap on the inlet side will
prevent liquid from entering the compressor (see section
1.4). It is of equal importance to protect the discharge
side of the compressor from liquid entry. This may be
done by installing a check valve on the discharge side of
the compressor combined with a piping design that does
not allow liquid to gravity drain into the compressor.
For vapor recovery applications, be certain to install
a check valve on vapor lines discharging to the liquid
space of the tank.
All piping must be in accordance with the laws and codes
governing the service. In the United States, the following
codes apply:
For LP Gas—The National Fire Protection Association
Pamphlet No. 58, Standard for the Storage and Handling
of Liquefied Petroleum Gases.
For Ammonia—The American National Standards
Institute, Inc., K61.1-1989, Storage and Handling of
Anhydrous Ammonia.
Install, use, and maintain this equipment according to
Corken instructions and all applicable federal, state, and
local laws and codes.
2.4 Liquid Trap
Compressors are designed to pressurize gas and not pump
liquids. The entry of even a small amount of liquid into the
compressor will result in serious damage to the compressor.
A liquid trap (scrubber) must be installed in the suction
piping and discharge line if condensate can drain back
to the compressor.
Pressure gauge
(0–400 PSI)
Liquid level
switches
1/2" NPT openings
for sight glass
ASME Class 300 RF
Liquid level
switches
Relief valve
Manual
drain valve
ASME
Class 300
RF 3"
outlet
ASME
Class 300
RF 3"
inlet
ASME
Class 300
RF inlet
ASME
Class 150
RF outlet
Figure 2.4
7

If the compressor is equipped with a liquid trap not
manufactured by Corken, make sure it is adequately
sized; otherwise, it may not be able to remove the liquid
entrained in the suction stream.
Corken’s liquid trap provides the most thorough liquid
separation (see figure 1.4) and is American Society of
Mechanical Engineers (ASME) code stamped. It contains:
• Manual drain valve.
• Relief valve designed according to the ASME code to
protect the vessel
• Pressure gauge with isolation needle valve
• Two (2) level switches: one for alarm and one for
shutdown. In some cases, the alarm switch is used to
activate a dump valve (not included with trap) or sound
an alarm so the operator can drain the trap using the
manual drain valve at the bottom of the trap.
• This trap also contains a mist pad. A mist pad is a mesh
of interwoven wire designed to remove fine liquid mists.
NOTE: The liquid level switches MUST be removed
from the trap before grounding any welding devices
to the trap or associated piping. Failure to do so will
damage the switch contacts!
2.5 Driver Installation and Flywheels
Corken compressors may be driven by either electric
motors or internal combustion engines (e.g. gasoline,
diesel, natural gas, etc.). They are usually V-belt driven.
The fly wheel has dual purpose it is sheave for the
V-belts and for compressor speed variation reduction.
The electric motor wiring is extremely important and
must be done by a competent electrician. Low voltage
or improper wiring of the motor will result in expensive
consequences. If there is a low voltage problem, call the
power company.
Humid climates can cause problems with explosion
proof motors. Explosion proof and TEFC motors are
designed to expand and contract due temperature
changes. This allows air to enter and exit the enclosures.
The moist air inside the motor can condense and if
enough water accumulates, the motor will fail.
To prevent this two method can be followed
• Make a practice of running the motor at least once
a week on a bright, dry day for an hour. During this
period of time, the motor will heat up and vaporize the
condensed moisture.
• Motor space heaters are recommended which need to
be powered at all times to vaporize the any moisture.
NOTE: No motor manufacturer will guarantee their
explosion proof or totally enclosed (TEFC) motor
against damage from moisture.
Drivers should be selected so the compressor operates
between 400 and 1200 RPM. The unit must not
be operated without the flywheel or severe torsional
imbalances will result causing vibration and a high
horsepower requirement. The flywheel should never
be replaced unless it has a higher wk2 value than the
flywheel supplied from factory.
For installation with engine drivers, thoroughly review
instructions from the engine manufacturer to assure the
unit is properly installed.
2.6 Crankcase Lubrication
The crankcase was drained before shipment. Before
starting the machine, fill the crankcase to the full mark
on the oil bayonet and not above. To ensure proper
lubrication of the crankcase parts, the crankcase should
be filled through the crankcase inspection plate (see
figure 2.6A for the proper oil filling location).
General Notes on Crankcase Oil
Corken gas compressors handle a wide variety of
gases in a multitude of operating conditions. They
are used in all areas of the world from hot dusty
deserts, to humid coastal areas, to cold arctic climates.
Some compressors may be lightly loaded and run
only occasionally, while others may be heavily loaded
and operate 24/7. Thus, no single crankcase oil or
maintenance schedule is right for every compressor.
Availability of brands and grades of oil can vary from
one location to another. These factors can make it
Figure 2.6A
Inspection plate
Inspection plate
gasket
Crankcase
Fill crankcase
through this opening
8

challenging for a Corken compressor user to select a
suitable crankcase oil. This guide is intended to aid in
that regard.
Compressor
Model
Approximate Capacity
Quarts Liters
HG/THG600 76.6
Figure 2.6B
It is safe to say that purchasing a quality crankcase oil,
and changing it regularly, is significantly less costly than
the repair bill and downtime associated with a lubrication
failure in any gas compressor. Considering the relatively
small volume of oil used in Corken compressors, and the
critical nature of the services where these compressors
are used, selecting the appropriate high quality oil is
the most economical choice. It will help ensure the
dependability and longevity of the compressor.
Corken recommends using industrial oils (rather than
engine oil or “motor oil”). Industrial oils have additives
selected and blended for specific purposes. Many are
designed specifically for the challenges inherent in
compressor crankcases. Industrial oils are available as
a conventional (mineral based) oil, a synthetic oil, or a
blend of the two.
All new Corken compressors are tested at the factory
using a conventional mineral oil. This oil is drained
prior to shipment. An oil suitable for the anticipated
environmental and operating conditions must be
selected and added to the compressor prior to the
initial startup.
Oils to Avoid
Selecting a crankcase oil based on low price or easy
availability is seldom the best decision. Following are oils
to avoid:
• Do not use any oil with a viscosity index below 95.
• Do not use any oil with a pour point less than 20°F
(11°C) lower than the anticipated minimum ambient
temperature (unless a crankcase oil heater is used).
• Do not use engine/motor oil.
See below for additional detail on each of these parameters.
Critical Oil Characteristics
Viscosity
Viscosity is the most important physical property of
lubricating oil. Simply put, the viscosity of an oil is a
measure of its resistance to flow. In gas compressors,
oils with higher viscosity (like ISO 100) are thicker and
are used for higher ambient temperatures. Oils with lower
viscosity (like ISO 68) are thinner and are used at lower
ambient temperatures. If the oil’s viscosity is too high, the
oil may not circulate through the compressor adequately.
If the viscosity is too low, the lubricating film will be
unable to protect the components from wear.
Viscosity Index
Viscosity Index (VI) is a measure of how much the
oil’s viscosity changes as its temperature changes. A
low viscosity index is an indication that the viscosity
changes more as the temperature changes. Oils with low
viscosity index tend to become thin as the oil temperature
increases. This can cause lubrication failure as well as
unstable oil pressure. A high viscosity index reflects
a more stable viscosity, and is generally preferred for
Corken compressors. The minimum Viscosity Index for
oils used in Corken compressors is 95 (VI is a unit-less
number). This is particularly important when operating
at high or low temperature extremes, or at a variety of
ambient temperatures (seasonal changes). Oils with a high
viscosity index can be used at wider ambient temperature
range compared to oils with a lower viscosity index.
It should be noted that a conventional oil (not synthetic)
with a high viscosity index may not necessarily be
suitable for continuous service at high temperature.
Such an oil will oxidize faster than a synthetic oil.
Synthetics have naturally high viscosity index, and are
therefore recommended for “heavy service” as described
below—including high temperature and continuous duty
applications. It many climates, the use of the correct
synthetic oil will eliminate the need to change oil viscosity
grades as the seasons change.
Pour Point
The pour point of an oil is the lowest temperature at
which the oil flows. At temperatures below the pour
point, the oil is essentially solid and can’t freely flow to
the compressor’s bearings and other wear surfaces, or
even to the compressor’s oil pump.
The oil’s pour point is particularly critical when starting
a compressor at low temperature conditions. An oil
should have a pour point at least 20°F (11°C) below the
lowest expected ambient temperature. For example,
if the minimum ambient temperature is expected to
be 0°F (-18°C), the pour point must be no higher than
-20°F (-29°C).
Do not assume the pour point of an oil is low enough.
Consult the oil’s technical data sheet – generally available
on the oil manufacturer’s website. Many conventional oils
have a pour point around 0 to 15°F (-18 to -9°C) which is
too high to use at low ambient temperatures. Synthetic oils
generally have a lower pour point than conventional oils.
Crankcase Oil Recommendations
The primary factors for selecting a suitable crankcase oil
from the chart below are ambient temperature range and the
9

anticipated service – normal service or heavy service. The
ambient temperature determines the required oil viscosity.
Consider the full range of high and low ambient temperatures
at the compressor’s location when selecting an oil. It may
be necessary to use an ISO 100 in summer and an ISO
68 in winter. Synthetic oils generally have a wider ambient
temperature range due to their higher viscosity index.
For the purpose of selecting a suitable crankcase oil for
a Corken compressor, normal and heavy service are
defined below.
Normal Service
“Normal service” can be defined as anything that is not
considered “heavy service” as described below.
Common examples of “normal service” applications:
• LPG liquid transfer (intermittent duty)
• Ammonia liquid transfer (intermittent duty)
• Most tank evacuation applications
Conventional mineral based oils have been used
successfully for many years in these services.
Heavy Service
“Heavy Service” is defined as an application where the
compressor is subject to any one (or more) of the following:
• Continuous duty service (several hours each day or more)
• Compressor consistently loaded at or near its maximum
horsepower rating
• Compressor speed is at or near its maximum speed rating
• Services with a “wet” gas such as natural gas with high
content of heavy hydrocarbons such a butane, pentane, etc.
• Services dealing with low vapor pressure hydrocarbons
(such as butane unloading in winter) where condensation
in the gas can result in dilution of the crankcase oil
• Compressors operating at high or low temperature extremes
Synthetic oils are recommended for “heavy” services.
Crankcase Oil Recommendations (Except Ammonia Service)
Normal Service
Ambient Temperature 1 Oil Product Oil Type 2 Viscosity ISO 3 Viscosity Index 3 Pour Point 3
40 to 100°F (4 to 38°C) Mobil DTE 10 Excel 100 C100 127 -27°F (-33°C)
Mobil Rarus 427 C100 100 16°F (-9°C)
Phillips 66 Gas Compressor Oil C100 102 -20°F (-29°C)
Chevron Regal R&O C100 97 5°F (-15°C)
Sunoco Sunvis 900 C100 95 -15°F (-26°C)
10 to 65°F (-12 to 18°C) Mobil DTE 10 Excel 68 C68 156 -38°F (-39°C)
Mobil DTE Heavy Medium C68 95 5°F (-15°C)
Phillips 66 Premium Gas Compressor Oil B68 133 -27°F (-33°C)
Chevron Regal R&O C68 99 -11°F (-24°C)
Sunoco Sunvis 900 C68 104 -21°F (-29°C)
Heavy Service
10 to 100°F (-12 to 38°C) Mobil SHC 627 4 S100 162 -49°F (-45°C)
Royal Purple Synfilm NGL 100 S100 130 -44°F (-42°C)
Dyna-Plex 21C Synzol CO ISO 100 S100 132 -49°F (-45°C)
-20 to 90°F (-29 to 32°C) Mobil SHC 626 4 S68 165 -59°F (-51°C)
Royal Purple Synfilm NGL 68 S68 132 -76°F (-60°C)
Crankcase Oil Recommendations (Ammonia Service Only)
Normal Service
Ambient Temperature 1 Oil Product Oil Type 2 Viscosity ISO 3 Viscosity Index 3 Pour Point 3
40 to 100°F (4 to 38°C) Mobil Rarus 427 C100 100 16°F (-9°C)
10 to 65°F (-12 to 18°C) Phillips 66 Ammonia Compressor Oil C68 102 -27°F (-33°C)
Chevron Capella P68 C68 96 -44°F (-42°C)
Mobil Rarus 426 C68 105 16°F (-9°C)
Heavy Service
10 to 100°F (-12 to 38°C) Mobil Gargoyle Arctic SHC 228 5 S100 147 -43°F (-45°C)
Royal Purple Uni-Temp 100 S100 124 -53°F (-47°C)
-20 to 90°F (-29 to 32°C) Mobil Gargoyle Arctic SHC 226E 5 S68 136 -58°F (-50°C)
Royal Purple Uni-Temp 68 S68 118 -51°F (-46°C)
1 Consult Corken for oil recommendations in very hot climates—ambient temperatures consistently above 100°F (38°C).
2 Oil type: C=Conventional, S=Synthetic, B=Conventional/Synthetic blend
3 Information available from oil manufacturers at the time of publication.
4 Mobil SHC oils are synthetic oils which require that the crankcase be flushed of residual mineral oil.
5 Mobil Gargoyle Arctic SHC oils are synthetic oils which require that the crankcase be flushed of residual mineral oil.
10

Ammonia Service
Compressing ammonia presents particular challenges
from a lubrication standpoint. Never use a detergent
oil in a compressor in ammonia service. Ammonia will
react with the detergent and cause lubrication failure.
Fortunately, some oils are specifically blended for use in
ammonia compressors — though some of these are best
suited only for cooler climates.
Consult these charts or the oil manufacturer’s product
data sheet for information regarding the oil’s viscosity,
viscosity index, pour point, etc. This information is
generally available on line or from the oil supplier. Do not
use an oil if it’s critical properties can not be confirmed,
of if there is any other reason to doubt its suitability.
Contact Corken if additional assistance is needed when
selecting a crankcase oil.
Oil Change Intervals
Oil change intervals can vary significantly depending
on local environmental conditions, the gas being
compressed, and the oil being used. Unless there are
factors that shorten the life of the oil, the following
recommendations apply:
Conventional oil: 2200 hours or 6 months—whichever
comes first
Synthetic oil: 6000–8000 hours* or one year—whichever
comes first
* Oil change intervals in this range should be confirmed via oil analysis.
Environmental or operational issues such as dirty/dusty or
humid conditions will require more frequent oil changes.
Contamination/dilution of the oil by liquids in the gas stream
can also shorten the life of the oil. Visually check the oil level
and the oil condition at least monthly (compare to unused oil).
Indications that dictate more frequent oil changes:
• Unusually dirty or discolored oil (or unusual smell)
• Oil dilution by condensation or other liquids in the gas
stream (see below)
• Change in viscosity for any reason (various oil additives
can break down over time)
• Changing ambient temperature may cause the need for
a different viscosity
The oil should be changed as often as necessary to
maintain clean, undiluted oil of the proper viscosity. Each
time the oil is changed, the oil filter (Corken part number
4225) should also be changed.
Oil analysis
The best way to determine the needed oil change interval
for any particular compressor is to have an oil analysis
conducted. Numerous labs can analyze a used oil sample
and advise its condition. After 2–3 such tests, a determination
can be made for a recommended oil change interval for a
particular compressor in its specific environmental situation
and operating conditions. Regular oil analysis can help
improve the compressor durability and decrease oil usage
by maximizing the oil change intervals. Based on the oil
analysis, the oil can be changed when it is needed, and not
changed when it is not yet necessary.
Oil dilution
Crankcase oil can be diluted by various products in the
gas stream. As an example, when compressing butane
in winter, the vapor pressure is very low and there can
be a lot of entrained liquid butane with the gas stream.
This liquid can collect in the compressor and dilute the
crankcase oil. This thins the oil and reduces its ability to
properly lubricate the compressor.
Hydrocarbon mixtures containing heavy hydrocarbons
such as butane, pentane, hexane, etc. often operate
at pressure above the vapor pressure of these heavier
constituents. Thus, they often produce a “wet” gas which
can dilute the crankcase oil.
Long term storage
When a compressor is removed from long term
storage, the oil should be changed before putting the
compressor back into service. Specifically, if it has
been unused over a season (such as over a winter), the
oil should be changed.
Crankcase Oil Heater Option
Corken offers a crankcase oil heater as an option on
all models except the small model 91. This heater is
available in 110V and 220V versions and is rated for Class
1, Division 1 and 2, Group B, C, D service. The heater
includes a thermostat set at 70°F (21.1°C). The heater
alleviates concerns about cold weather startup. When
using the heater, an ISO 100 viscosity oil will do well
regardless of low ambient temperature.
Note that all Corken HG600 compressors come ready to
accept the optional heater.
Cylinder Lubricating Oil
All Corken gas compressors are designed to operate
without cylinder lubrication. However, many Corken
Customers, particularly in the oil and gas industry, use
lubricated compressor cylinders to extend the service
life of the compressor’s valves, piston rings, and packing.
Compressor cylinders operate at higher temperatures
than the crankcase, so oils used in this service often have
a higher viscosity than the crankcase oil. A viscosity of
ISO 150 (or higher) is common for cylinder lube oil. Several
companies make oil specifically designed for this service
and many of these oils have properties that inhibit dilution
or washing away of the oil by condensates in the process
11

gas. These oils typically also have properties that prevent
corrosion and carbon buildup in the cylinders and valves.
Contact Corken is assistance is needed in selecting a
suitable cylinder lubricating oil. Oil manufacturers are
often a good source for this information as well.
Engine oils (motor oils) should never be used as a cylinder
lubricant. The additives in engine oil are poorly suited for
that purpose.
Engine Oils (Motor Oils)
At noted above, engine oils (or motor oils) are
not recommended for use in Corken compressor
crankcases or cylinders. Engine oils are formulated
for use in internal combustion engines and contain
additives that specifically counter the contaminants
created by the combustion of fuel (soot, CO2, water,
etc.). As such, they are not necessarily the best oils to
use in a gas compressor.
Detergents and dispersants in engine oils can react
with the compressor’s process gas, or form emulsions
inside the compressor’s crankcase that are detrimental
to lubrication. Ultimately, this negatively effects the
oil’s properties and damages the compressor’s critical
internal components.
If a suitable industrial oil is not readily available, engine oils
can temporarily be used in Corken compressors in normal
service, but only until a suitable industrial oil can be sourced
(see above for definition of “normal service”). Engine oils
should not be used for compressors in “heavy service”.
Engine oil is labeled with an API “donut” indicating the
API Service Grade. It is critical that the engine oil have
an API Service Grade of SJ or better. Engine oils with
an API Service Grade of SA and SB are obsolete, but still
readily available. These very low quality oils should never
be used in Corken compressors. Industrial oils do not
receive an API Service Grade like engine oil does.
2.7 Relief Valves
A relief valve should be fitted in the piping between
the compressor discharge any device that blocks or
restricts the gas flow. Relief valves should be properly
sized and made of a material compatible with the gas
being compressed and temperatures generated by the
compressor. Local codes and regulations should be
checked for specific relief valve requirements. Also, relief
valves may be required at other points in the compressor’s
system piping like to protect ASME code vessels.
A rule of thumb to select the set pressure on a relief valve
located on compressor piping discharge is for it to be
between 10–20% above the highest discharge pressure
the compressor can produce, but less than the maximum
compressor working pressure. This can vary with relief
valve manufacturer so consult the valve supplier.
2.8 Shutdown/Alarm Devices
For all applications, shutdown/alarm sensors (switches
or transmitters) provide worthwhile protection that may
prevent serious damage to the compressor system. All
electronic devices should be selected to meet local code
requirements. Shutdown/alarm devices typically used on
Corken compressors are as follows:
1. Low Oil Pressure Sensor: Shuts down the unit if
crankcase oil pressure falls below 15 psig (1.03 bar g)
due to oil pump failure or low oil level in crankcase.
The switch or the compressor controller must have
a 30 second delay on startup which allows the
compressor to build oil pressure in the crankcase.
2. High Discharge Temperature Sensor: This sensor is
strongly recommended for all applications. Both sensor
and the compressor have an operating range. It is
preferable that the sensor set point be 30°F (17°C) above
the normal compressor discharge temperature, but below
the maximum design temperature for O-ring material
used on the compressor (see note below). The O-ring
code can be found on the compressor model number.
Note: Maximum temperature for these material are:
• Buna-N and Neoprene®1 250°F (121°C)
• Viton®1 and PTFE 350°F (177°C)
1
Registered trademark of the DuPont Company.
3. Low Suction Pressure Sensor: Shuts down the unit
if inlet pressure is below a preset limit (set point). The
set point should follow these guidelines:
• For safety shut off it must be greater than
the compressor minimum suction pressure
(atmospheric) to prevent pulling oil from the
crankcase into the gas stream.
• For process shut off a good rule of thumb set point
is 25% of product vapor pressure. It can be lower
or higher based on economic decision on how
much product can be recovered. This decision
must be made by the customer.
4. High Discharge Pressure Sensor: Shuts down
the unit if outlet pressure is above a preset limit (set
point). The set point should follow these guidelines:
• Less than the compressor’s maximum working
pressure.
• Less than 80–90% of the relief valve pressure set
point (consult relief valve manufacturer)
• Greater than the compressor’s discharge pressure
based on normal operating conditions.
5. Vibration Switch: Shuts down the unit if vibration
becomes excessive.
12

Chapter 3—Starting Up the
Compressor
The initial operation of the compressor is the most critical
time it will ever face. READ ALL OF CHAPTER TWO BEFORE
PROCEEDING TO THE STARTUP CHECKLIST.
3.1 Inspection After Extended
Storage
If the compressor has been out of service for a long
period of time, make sure the cylinder bore and valve
areas are free of rust and other debris. For valve and/or
cylinder head removal instructions, refer to chapter 4 of
this IOM manual.
Drain the oil from the crankcase and remove the
crankcase inspection plate. Inspect the running gear for
signs of rust and clean or replace parts as necessary.
Fill crankcase with the appropriate lubricant through the
crankcase inspection plate opening. Squirt oil on the
crossheads and rotate the crankshaft by hand to ensure
that all bearing surfaces are coated with oil.
Rotate unit manually to ensure running gear functions
properly. Replace the crankcase inspection plate and
proceed with startup.
3.2 Flywheel and V-belt Alignment
Before working on the drive assembly, be sure that the
electric power is disconnected. When mounting new
belts, always make sure the driver and compressor are
close enough together to avoid forcing.
Improper belt tension and sheave alignment can cause
vibration, excessive belt wear and premature bearing
failures. Before operating the compressor, check alignment
of the V-grooves of the compressor flywheel and driver
sheave. Visual inspection often will indicate if the belts are
properly aligned, but use of a square is the best method.
The flywheel is mounted on the shaft via a split, tapered
bushing and three bolts (refer to figure 3.2A). These bolts
should be tightened in an even and progressive manner until
torqued as specified below. There must be a gap between
the bushing flange and the flywheel when installation is
complete. Always check the flywheel runout before startup
and readjust if it exceeds the value listed in Appendix B.
Align hub with crankshaft key.
Flywheel
Tighten ywheel bolts in an even and progressive manner.
Flywheel removal holes
(threaded openings)
Split
Crankshaft key
Figure 3.2A (model HG601EE (plain style) shown)
13

Hub
Size
Diameter
in. (cm)
Bolt Torque
Ft-lb (kg-meter)
Set Screw
Torque Ft-lb
(kg-meter)
SF 4.625 (11.7) 12–18 (1.7–2.5) 22 (3.1)
E6.0 (15.2) 30–36 (4.1–4.9) 22 (3.1)
J7.25 (18.4) 75–81 (10.3–11.1) 10 9 (15.1)
Figure 3.2B
Tighten the belts until they are taut, but not extremely
tight. Consult the V-belt supplier for specific tension
recommendations. Belts that are too tight may cause
premature bearing failure. Refer to figure 3.2B.
3.3 Crankcase Oil Pressure
Adjustment
The compressor is equipped with an automatically
reversible gear type oil pump. It is essential to ensure
the pumping system is primed and the oil pressure is
properly adjusted in order to assure smooth operation.
Before starting the compressor, check and fill the
crankcase with the proper amount of lubricating oil
(see figure 1.6B for details).
When the compressor is first started, observe the
crankcase oil pressure gauge. If the gauge fails to
indicate pressure within 30 seconds, stop the machine
and loosen the oil filter. Restart the compressor and
run until oil comes out and tighten the filter.
The oil pressure should be about 20 psi (1.4 bars)
minimum for normal service. If the discharge pressure
is above 200 psi (13.8 bars) the oil pressure must be
maintained at a minimum of 25 psi (1.7 bars). A spring-
loaded relief valve mounted on the bearing carrier
opposite the flywheel regulates the oil pressure. As
shown in figure 3.3, turn the adjusting screw clockwise
to increase the oil pressure and counterclockwise to
lower it. Be sure to loosen the adjusting screw locknut
before trying to turn the screw and re-tighten it after
making any adjustment.
Oil pressure relief valve
adjustment screw
Locknut
Oil pressure guage
Bearing carrier
Figure 3.3
Figure 3.2C
NOTE:
1) When using five individual V-belts (5V or 5VX), 1/4 to 3/8 inches (6.4 to 9.5 mm) of movement is normal.
2) When using five banded V-belts, movement will be much less due to the stiffness of the banded V-belt design.
14

3.4 Compressor Speed and
Rotation Direction
The lubrication system of the Corken horizontal
compressor is designed to operate at a minimum of 400
RPM. If lower speeds are necessary, consult the factory.
The maximum speed is 1200 RPM. The crankshaft may
be rotated in either direction.
3.5 Compressor Cooling
AIR COOLED: Double acting units generate a lot of
heat around the valve area. It is very important that
the compressor be located where good air flow and
ventilation can be provided. In extreme cases external
cooling fans can be used to provide additional air flow
across the cylinders.
WATER COOLED: If the compressor has water cooled
cylinders (optional), be sure that the cooling system
has been inspected for leaks and proper circulation.
Purge air from the cooling jackets to eliminate air
pockets in the cooling system. If chilled water systems
are used be sure that water shut-off valves are
installed to stop water flow when compressor stops.
Monitor system for any signs of internal sweating. If
internal moisture is detected, water temperatures and
flow rates should be checked. Normal flow rate for
cylinders is approximately 1–2 gpm.
3.6 Force Feed Cylinder
Lubrication (Lubed models only)
An external lubricator is bolted directly to the crankcase
and is driven by a chain inside the crankcase at 80%
of crankshaft speed. To ensure each cylinder receives
the same volume of lubrication, an oil divider valve
assembly is also mounted to the opposite end of
the crankcase (see lubricator assembly details in
Appendix D). Since lubricators supplied with Corken
compressors are made by a number of different
manufacturers, refer to the manufacturer’s instructions
provided with the lubricator for specific details on
priming, adjusting, and maintaining the lubricator.
Basic operating instructions and flow rate adjustments
are also listed on the side of the lubricator reservoir.
At the initial setup of the compressor, the lubricator
flow should be set to maximum capacity. After the first
hour, reduce the flow to normal operating levels. Normal
operating levels range from three to six drops per minute
depending upon the cylinder size.
NOTE: The lubricator supplied with a CORKEN
compressor must be supplied with oil from an external
supply tank and NOT from the compressor crankcase
or lubricator reservoir.
Oil types: Refer to section 2.6 (crankcase lubrication).
Reservoir
sight glass
Priming button
Oil inlet (1/8″)
Drive shaft
Drip tube sight glass
Lock nut
Mounting
studs
Oil outlet (1/8″)
Union nut
Mounting stud
Reservoir
Flushing unit
Oil ll opening
Drain
plug
Typical lubricator shown above.
NOTE:
1) Since Corken uses more than
one vendor when purchasing
lubricators, the lubricator shown
and respective operational
instructions may vary from the
one used on the compressor.
2) Operational instructions can
be found on the side of the
lubricator reservoir.
3) Oil used in the reservoir is for
lubricating the internal parts of
the lubricator only and not the
compressor.
4) Depending on the cylinder
size, the oil flow rate for the
drip tube site glass is three to
six drops per minute during
normal operations.
15

3.7 Variable Clearance Heads (VCH)
Variable clearance head (VCH) assemblies (outboard)
allow adjustment of the compressor when operating
conditions change. Turning the clearance volume adjusting
cup changes the capacity and bhp requirements of the
cylinder. Normally, the packager has already provided
at least a preliminary adjustment of the VCH. If not, it
may be necessary to adjust the heads for maximum
clearance before startup. After startup, adjust the heads
inward to increase the capacity and bhp of the cylinder
to the desired levels.
To adjust the variable clearance heads, follow the steps
below.
1) Remove the VCH adjusting screw nut. Adjustment can
be made while the unit running.
2) Turn the end of the adjusting cup to adjust the cylinder
head end clearance.
3) Turning the end of the adjusting cup inward (clockwise)
reduces cylinder head end clearance.
4) Turning the end of the adjusting cup outward
(counterclockwise) increases cylinder head end
clearance.
5) Replace the VCH adjustable screw nut and O-ring.
The approximate clearance volume change per turn of
the adjusting bolt is 3%.
3.8 Startup Check List
Please verify all of the items on this list before
starting the compressor! Failure to do so may result
in a costly (or dangerous) mistake.
Before Starting the Compressor
1. Become familiar with the function of all piping
associated with the compressor. Know each line’s use!
2. Verify that actual operating conditions will match the
anticipated conditions.
3. Ensure that line pressures are within cylinder
pressure ratings.
4. Clean out all piping.
5. Check all mounting shims, cylinder and piping
supports to ensure that no undue twisting forces exist
on the compressor.
6. Verify that strainer elements are in place and clean.
7. Verify that cylinder bore and valve areas are clean.
8. Check V-belt tension and alignment. Check drive
alignment on direct drive units.
9. Rotate unit by hand. Check flywheel for wobble or play.
10.Check crankcase oil level.
11. Drain all liquid traps, separators, etc.
12. Verify proper electrical supply to motor and panel.
13. Check that all gauges are at zero level reading.
14. Test piping system for leaks.
15. Purge unit of air before pressurizing with gas.
16.Carefully check for any loose connections or bolts.
17. Remove all stray objects (rags, tools, etc.) from
vicinity of unit.
18. Verify that all valves are open or closed as required.
19. Double-check all of the above.
After Starting Compressor
1. Verify and note proper oil pressure. Shut down and
correct any problem immediately.
2. Observe noise and vibration levels. Correct
immediately if excessive.
3. Verify proper compressor speed.
4. Examine entire system for gas, oil or water levels.
5. Note rotation direction.
6. Check startup voltage drop, running amperage and
voltage at motor junction box (not at the starter).
7. Test each shutdown device and record set points.
8. Test all relief valves.
9. Check and record all temperatures, pressures and
volumes after 30 minutes and one hour.
10.After one hour running time, tighten all head bolts,
valve holddown bolts, and baseplate bolts. See
Appendix B for torque values.
16

Item to Check Daily Weekly Monthly Six
Months Yearly
Crankcase oil pressure
Compressor discharge pressure
Overall visual check
Crankcase oil level 1 1
Drain liquid from accumulation points 2
Drain distance pieces
Clean cooling surfaces on compressor and
intercooler (if any) 4
Lubricator supply tank level (if any)
Check belts for correct tension
Inspect valve assemblies
Lubricate motor bearings in accordance with
manufacturers’ recommendations
Inspect motor starter contact points
Inspect piston rings
13
Chapter 4—Routine Maintenance Chart
1 Change oil every 2,200 hours of operation or every 6 months, whichever occurs first. If the oil is unusually dirty, change it as often as needed to maintain a
clean oil condition. Change replacement filter 4225 with every oil change.
2 Liquid traps should be drained prior to startup.
3 Piston ring life varies greatly, depending on application, gas, and operating pressures. Consult factory for additional recommendations for a specific application.
4 Follow all safety precautions and use appropriate PPE (glasses, eye protection, special clothing, etc.) while cleaning. In particular, verify cooling fins are
cleaned regularly with a non-toxic, non-flammable, non-corrosive cleaning agent.
Chapter 5—Routine Service and
Repair Procedures
CAUTION: Always relieve pressure in the unit
before attempting any repairs. After repair,
the unit should be pressure tested and checked for
leaks at all joints and gasket surfaces.
If routine maintenance is performed as listed in chapter
4, repair service is generally limited to replacing
valves or piston rings. When it comes time to order
replacement parts, be sure to consult the part details
appendix in the back of this Installation, Operation &
Maintenance (IOM) manual for a complete list of part
numbers and descriptions.
5.1 Compressor Valves
Test the compressor valves by closing the inlet piping valves
while the unit is running; however, do not allow the machine
to operate in this way very long. If the inlet pressure gauge
does not drop to zero almost immediately, one or more of the
compressor valves is probably damaged or dirty. However, it
is possible for the pressure gauge itself to be faulty.
In most cases, if a compressor valve or valve gasket
is leaking, it will create more heat. On a single stage
compressor, compare the operating temperatures of the
two suction or discharge valves and cover plates to each
other. If a valve or gasket is leaking, it will have a higher
operating temperature. NOTE: This method will not be
suitable for two stage compressors if each stage does
not have more than one valve.
Each suction and/or discharge valve assembly is easily
removed as a unit for inspection. If any part of the
valve assembly is broken, the valve assembly should be
replaced. See valve assembly parts details in the Appendix
Dfor a complete list of part numbers and descriptions.
If a compressor valve is leaking due to dirt or any other
foreign material that keeps the valve plate and seat from
sealing, the valve may be cleaned and reused. New gaskets
and/or O-rings should be used to ensure a good seal.
The valve holddown components and valve assemblies
listed in Appendix D show the various specifications
used on horizontal compressors. Since more than one
suction valve arrangement is available for each model of
compressor, it is necessary to know the complete model
number so the valve type specification number can be
identified (see example listed below).
Model number THG601BBGM 4 FBANSNNN
Valve type = spec 4
17

Valve Inspection and/or Replacement
Before removing and inspecting the valves, begin by
depressurizing and purging (if necessary) the unit and
refer to Appendix D.
Disassembly of 2.75" Cylinder Size
1. Remove the valve cover plate and O-ring by removing
each of the three bolts.
2. After the cover plate and O-ring have been removed,
the valve assembly and valve gasket can be lifted out.
3. Inspect valves for breakage, corrosion, debris and
scratches on the valve plate. In many cases, valves
may simply be cleaned and reinstalled. If the valves
show any damage, they should be repaired or
replaced. Replacement is usually preferable although
repair parts are available. If valve plates are replaced,
seats should also be lapped until they are perfectly
smooth. If more than .005 of an inch must be removed
to achieve a smooth surface, the valve should be
discarded. If plates are replaced without re-lapping
the seat, rapid wear and leakage may occur.
Assembly of 2.75" Cylinder Size
1. Insert metal valve gasket into the suction and/or
discharge opening of the head. The metal valve
gasket should always be replaced when the valve
is reinstalled.
2. Insert cleaned or new valve assembly. Make sure the
suction and discharge valves are in the proper suction
and discharge opening in the head.
3. Replace the O-ring and valve cover plate. Torque
the bolts to the value listed in Appendix B. NOTE:
Gaskets and O-rings are not normally reusable.
4. Check bolts after first week of operation. Re-torque if
necessary. See Appendix B for torque values.
Disassembly of 3.25", 4", 5", 6" and 8"
Cylinder Sizes
1. Unscrew the valve cap and remove the O-ring.
2. Remove the valve cover plate, O-ring and holddown
screw by removing each of the four bolts. The
holddown screw is easily removed with the special
wrench supplied with the compressor.
3. After the cover plate and O-ring have been removed,
the valve cage, valve assembly and valve gasket can
be lifted out.
4. Inspect valves for breakage, corrosion, debris and
scratches on the valve plate. In many cases, valves
may simply be cleaned and reinstalled. If the valves
show any damage, they should be repaired or
replaced. Replacement is usually preferable although
repair parts are available. If valve plates are replaced,
seats should also be lapped until they are perfectly
smooth. If more than .005 of an inch must be removed
to achieve a smooth surface, the valve should be
discarded. If plates are replaced without re-lapping
the seat, rapid wear and leakage may occur.
Assembly of 3.25", 4", 5", 6" and 8" Cylinder Sizes
1. Insert metal valve gasket into the suction and/or
discharge opening of the head. The metal valve
gasket should always be replaced when the valve
is reinstalled.
2. Insert cleaned or new valve assembly. Make sure the
suction and discharge valves are in the proper suction
and discharge opening in the head.
3. Insert the valve cage.
4. Replace the O-ring and valve cover plate. Torque the
bolts to the value listed in Appendix B. CAUTION: Be
sure the holddown screw has been removed.
5. To ensure the valve gasket is properly seated, insert
the holddown screw and tighten to the value listed
in Appendix B. NOTE: Gaskets and O-rings are not
normally reusable.
6. Replace the O-ring and valve cap and tighten to the
value listed in Appendix B.
7. Check bolts and valve holddown screws after first
week of operation. Re-torque if necessary. See
Appendix B for torque values.
5.2 Heads
A horizontal compressor cylinder head or adjusting cap
seldom require replacement if the compressor is properly
maintained. The primary cause of damage to a cylinder
head and adjusting cap 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 heads and adjusting caps (for proper storage
instructions see chapter 6).
Many compressor repair operations require removal
of the cylinder heads and adjusting caps. While the
compressor is disassembled, special care should be
taken to avoid damage or corrosion. 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 re-tightened to the torque values listed in
Appendix B.
18

5.3 Piston Rings and Piston Ring
Expander Replacement
PistonRingLife—DryCylinderCompressorApplications
It is unrealistic to expect the same piston ring life from
a dry cylinder compressor as from a lubricated cylinder
machine because the PTFE rings have greater wear,
particularly under high temperature conditions.
CORKEN uses one of the best PTFE ring formulations
available. The normal life expectancy is approximately
2,200 hours of continuous service within recommended
compression ratios. However, ring life will vary considerably
depending upon piston speed (RPM), ambient temperature,
intermittent service conditions, compression ratio and the
nature of the gas being handled.
The secret to long ring life is operating at a low temperature.
A low ambient temperature and compression ratio along
with better intercooling will provide better ring wear.
Piston Ring Life—Lubricated Cylinder
Compressor Applications
If the compressor is equipped with cylinder lubrication,
piston rings have a longer service life than the dry
cylinder units described above.
Piston ring life varies considerably from application to
application but improves dramatically at lower speeds
and temperatures.
Piston and Piston Ring Expander Replacement
1. To replace the piston rings, depressurize the
compressor and purge if necessary.
2. Remove the cylinder cap (if any) and head.
3. Loosen the piston cap screws and remove the piston
cap as shown in figure 5.3 by pinching two loose
screws together.
Figure 5.3
4. Remove the lock nut, washer and shims and pull the
piston off the end of the piston rod. Keep track of which
piston washer and shims came out of each cylinder.
5. Piston rings and expanders may then be easily
removed and replaced. Corken recommends replacing
expanders whenever rings are replaced. To determine
if rings should be replaced, measure the radial
thickness and compare it to the chart in Appendix B.
5.4 Pistons
While reading the following instructions, refer to
Appendix D for parts details.
1. To replace the pistons, depressurize the compressor
and purge if necessary.
2. Remove the head (or adjusting screw nut, cylinder
cap, adjusting cup and head—applies to adjustable
head configuration only) as shown in Appendix D.
3. Remove the piston cap and shims by loosening and
removing the piston cap screws holding the piston cap
to the piston. Re-insert two loose screws as shown in
figure 5.3. Using fingers, pinch the screws together and
pull the piston cap out of the cylinder.
4. Remove the lock nut and thrust washer and pull the
piston out of the cylinder. Then, remove the thrust
washer and shims on the end of the piston rod.
5. Check the thrust washer and shims for damage and
replace if necessary.
6. Measure the thickness of the existing shims.
7. Insert one thrust washer against piston rod shoulder
followed by the same shims (or the same thickness of
shims) as before.
8. Before installing the piston, attach the piston ring
expanders and piston rings to the piston. Then, install
the piston on the piston rod.
9. Install a thrust washer and lock nut and tighten the
lock nut to the value listed in Appendix B.
10. Now remove an inboard valve and measure dimension
“Y” on the inboard end of the piston as shown in
Appendix B. If this measurement does not fall within
the tolerances listed in the piston assembly details
(Appendix B), remove the piston and adjust the shims
as necessary. Re-install the piston and tighten the
lock nut to the value listed in Appendix B. Re-measure
the “Y” dimension.
11. After the “Y” dimension is within tolerance, install
the piston cap with the same shim/shims (or same
thickness of shims) as before.
19

12. Torque the piston cap screws to the value listed in
Appendix B.
13.Install the head (or head and adjustable cap—
applies to adjustable head configuration only) as
show in Appendix D. Torque bolts to the value listed
in Appendix B.
14.Now remove an outboard valve and measure
dimension “X” at the outboard end of the piston as
shown in the Appendix B. If this measurement does
not fall within the tolerances in Appendix B, remove
the head (or head and adjustable cap—applies to
adjustable head configuration only) and piston cap
and adjust the shims as necessary. Re-install the
piston cap and tighten the piston cap screws in an
alternating sequence to the values listed in Appendix
B. Re-install the head (or head and adjustable cap—
applies to adjustable head configuration only) and
torque to the value listed in Appendix B. Re-measure
the “X” dimension again.
15. After the “X” dimension is within tolerance, remove
the adjustable cap and install the adjustable cup
followed by the adjustable cap and adjustable screw
nut as shown in Appendix D.
16.Torque the bolts in an alternating sequence to the
values listed in Appendix B.
17. Replace the previously removed valves. Best results
will be obtained if new valve gaskets are used.
18. Follow standard startup procedures.
5.5 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 cylinder
(for proper storage instructions see chapter 5). Damage
can also occur if the piston rings are allowed to wear so
much that the ring expander can reach the cylinder wall.
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.
If the cylinder does become 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 RING LIFE.
1) Keep foreign material out of crosshead bore on
crankcase. Wipe inside of bore with clean rag and
coat bore with oil.
2) Inspect piston rod for cleanliness and coat with oil
before assembly.
3) Before installing adapter and packing cartridge
on piston rod, install packing installation cone
(Corken #3905) over piston rod threads. This
will aid and protect packing during installation.
Failure to use this packing cone could result in
packing damage. Refer to Appendix D for correct
installation of packing.
4) Rotate flywheel/crankshaft by hand several revolutions
to ensure proper fit of all assembled parts.
5) Orient cylinder inlet and outlet to piping installation
to ensure proper valve alignment with system.
Valves must be properly oriented with suction and
discharge piping.
6) For piston installation instructions, see section 5.4.
7) After installing the piston, again, rotate flywheel/
crankshaft by hand several revolutions to ensure
proper fit of all assembled parts.
8) Check crankcase for proper oil level.
9) See startup procedure in section 3.7. During startup,
listen to the compressor for any unusual noises. If
any problems arise during assembly, please contact
the factory.
When reassembling the compressor, make sure the
bolts are retightened using the torque values listed in
Appendix B.
5.6 Packing Replacement
Instructions
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 specific construction details and actual part numbers,
consult Appendix D in the back of this Installation,
Operation & Maintenance (IOM) manual. Use instructions
below that apply to the MODEL and SERIAL NUMBER of
the compressor.
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