Corken D Series Instruction manual

Model FT891
Compressor
Model FD891
Compressor
Model D791
Compressor
Installation, Operation
& Maintenance Manual
D and T-Style Double-Acting Gas Compressors
All Models 791 and 891
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.
ORIGINAL INSTRUCTIONS IJ110H
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 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, 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 warrantee 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. To
ensure EU compliance, the compressor should be ordered with the optional 3022-1X Declaration of Conformity. 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—Features and Benefits ...............................................................4
Chapter 2—Installation ........................................................................5
2.1 Location .................................................................................5
2.2 Foundation ...............................................................................5
2.3 Piping ...................................................................................5
2.4 Liquid Trap ...............................................................................6
2.5 Driver Installation and Flywheels ..............................................................7
2.6. Crankcase Lubrication .....................................................................7
2.7 Purging, Padding, Venting, and Draining of Distance Pieces .......................................11
2.8 Relief Valves .............................................................................12
2.9 Shutdown and Alarm Devices ...............................................................12
Chapter 3—Start Up ..........................................................................12
3.1 Inspection After Extended Storage ...........................................................12
3.2 Flywheel and V-belt Alignment ..............................................................12
3.3 Crankcase Oil Pressure Adjustment ..........................................................13
3.4 Startup Check List ........................................................................14
Chapter 4—Routine Maintenance Chart .........................................................15
Chapter 5—Service Procedures ................................................................15
5.1 Valve s ..................................................................................15
5.2 Heads/Cylinder Cap ......................................................................16
5.3 Piston Rings and Piston Ring Expanders ......................................................16
5.4 Piston Replacement.......................................................................17
5.5 Piston Rod Packing Adjustment .............................................................17
5.6 Cylinder and Packing Replacement ..........................................................17
5.7 Bearing Replacement for Crankcase and Connecting Rod ........................................20
5.8 Oil Pump Inspection ......................................................................22
5.9 Gasket Sets .............................................................................23
Appendices
A. Model Number Identification Code and Available Options..........................................24
B. Specifications ............................................................................28
C. Outline Dimensions ........................................................................30
D. Parts Details .............................................................................34
E. Troubleshooting ...........................................................................50
F. Extended Storage Procedures................................................................51
3

Chapter 1—Features and Benefits
High-efficiency PEEK valves:
Offer quiet operation and increase durability in
process gas applications.
Ductile iron construction:
Maximum thermal shock endurance for cylinder
and head.
Self-lubricating PTFE piston rings:
Multiple material options provide the most
cost-effective operation of compressors for
non-lube service. The step-cut design
maximizes performance throughout the life of
the piston ring.
Positively locked pistons:
Simple piston design allows end clearance to be
precisely set to provide maximum efficiency and
long life.
Self-lubricating piston rod seals:
Seals constructed of PTFE incorporating special
fillers to minimize oil carry over and leakage.
Spring loaded seal design self adjusts to
compensate for normal wear.
Nitride-coated piston rods:
Impregnated nitride coating provides superior
corrosion and wear resistance.
Adjustable packing screw:
Ensures maximum sealing capacity during the
life of the packing (T791 and T891 models only).
Cast iron crossheads:
Durable cast iron crossheads provide
superior resistance to corrosion
and galling.
Pressure-lubricated crankcase with filter:
Self-reversing oil pump ensures proper
lubrication regardless of directional rotation
to main bearing and connecting rod bearings.
Standard 10-micron filter ensures long-lasting
bearing life.
Lower packing (V-ring)
Middle packing (V-ring)
Upper packing
(Segmented)
Upper distance piece
Lower distance piece
Construction details: Model FT891 compressor
Oil deflector ring
4

Chapter 2—Installation
2.1 Location
NOTE: Compressor must be installed in a well
ventilated area.
Corken’s compressors are designed for outdoor duty.
Consult the factory before installing a compressor in
extreme conditions such as corrosive environments and
arctic conditions for extended periods of time. Always
review the local safety regulations and building codes
and ensure the installation meets all local safety and
building standards.
Since Corken’s compressors typically handle toxic and
flammable gases, they should be located outdoors in
a well ventilated area. To ensure the compressor is
accessible from all sides and has unrestricted air flow
for adequate cooling, a minimum of 18 inches (45 cm)
clearance between the compressor and the nearest wall
is recommended.
Noise:
Many factors affect the noise level generated by a
compressor installation. Several of these, including
motor noise, piping vibration, foundation/skid design,
and surrounding structures are outside Corken’s control.
The use of sufficient pipe supports, flexible hoses, and
proper baseplate/skid support will all reduce noise. Thus,
Corken cannot guarantee a particular noise level from
our compressors. However, noise levels from a properly
installed Corken compressor typically do not exceed 85
dBa at three feet (0.91 meters).
2.2 Foundation
A proper foundation is essential for a smooth running
compression system. The compressor should be
mounted to a structural steel skid that is attached to a
concrete slab. The slab must be at least eight inches
thick with a two inch skirt around the circumference of
the structural steel skid. The structural steel skid should
be securely anchored into the foundation by 3/4 inch
diameter by eight inch long “J” bolts. The total mass of
the foundation should be approximately twice the weight
of the compressor system (compressor, structural steel
skid, motor, etc.). See figure 2.2 for details.
Main beam (C-beam or W-beam)
Cross beam (H-beam)
3/4" diameter “J” bolt
Hex nut
and washer
Concrete foundation
Ground level
Proper Foundation Design
Figure 2.2: Recommended foundation details for Corken compressors.
NOTE: For a more detailed explanation of a proper
foundation design, please refer to item number ED410
(Important Instructions for Compressor Foundation Design).
2.3 Piping
A proper piping design is as important as a proper foundation
when it comes to a smooth operating compressor. A
poorly designed piping system results in an undesirable
transmission of compressor vibration to the piping. For best
results follow the recommendations below.
DO NOT SUPPORT PIPING WITH THE COMPRESSOR.
Unsupported piping is the most frequent cause of
vibration. To minimize the transmission of vibration from
the compressor to the piping, install flexible connectors
vertically as shown below (see figure 2.3 for details).
Concrete
foundation
Steel
structural skid
Pipe
support
Flexible
connections
Flexible
connections
Ground level
Figure 2.3: Flexible connectors should be used to minimize
transmission of vibration to the piping.
To prevent excessive pressure drop between the suction
source and the compressor and the final discharge point
and the compressor, the piping must be adequately
5

sized. In most cases, piping should be at least the same
diameter as the suction nozzle on the compressor.
If a restrictive device such as a valve, pressure regulator,
or back-check valve is to be installed in the compressor’s
suction line, care must be taken. The suction line volume
between the restrictive device and the compressor
suction nozzle must be at least ten times the swept
cylinder volume.
On liquefied gas applications, a liquid trap must be
installed on the inlet side of the compressor. This prevents
liquid from entering the compressor (see section 2.4).
It is of equal importance to protect the discharge side of
the compressor from liquid entry. Always install a check
valve on the discharge side of the compressor and use
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., K61.1-1999, Storage and Handling of
Anhydrous Ammonia.
Copies of these are available from NFPA, 60 Baterymarch
Street, Boston, Mass, 02110 and ANSI, 1430 Broadway,
New York, N.Y., 10018. Install, use, and maintain this
equipment according to Corken’s instructions and all
applicable federal, state, and local laws and previously
mentioned codes. Other laws may apply in different
industries and applications.
2.4 Liquid Trap
Compressors pressurize gas and are not designed to
pump liquids. The entry of even a small amount of liquid
into the compressor results in serious damage.
On liquefied gas applications, a liquid trap must be used
to prevent liquid from entering the compressor.
Corken’s liquid trap is ASME code stamped and provides
the most thorough liquid separation (see figure 2.4).
It contains two 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 trap can be manually drained
by the operator. It also contains a mist pad; a mesh of
interwoven wire designed to remove fine liquid mists. The
ASME code trap comes standard on Corken’s 107B and
109B mountings.
NOTE: Before grounding any welding devices to the
trap or associated piping, the LIQUID LEVEL SWITCH
MUST BE REMOVED from the trap. Failure to do so will
damage the contacts of the switch.
Figure 2.4: ASME automatic liquid trap
Relief valve
Pressure gauge
Inlet
Shutdown switch
Liquid level alarm switch
Drain valve
Class 300 RF flange code-stamped automatic
liquid trap with two NEMA 7 liquid-level switches for
compressor shutdown and alarm. Equipped with relief
valve, pressure gauge, demister pad, and drain valve.
Process Connection Sizes:
• 2" x 2" Class 300 RF flange
6

If the compressor is equipped with a liquid trap not
manufactured by Corken, make sure it is adequately
sized to remove the liquid entrained in the suction stream.
2.5 Driver Installation and Flywheels
Corken’s vertical compressors can be driven by electric
motors or combustion engines (gasoline, diesel, natural
gas, etc.). A proper driver selection should turn the
compressor between 400 and 825 RPM.
NOTE: Never operate a reciprocating compressor without
a flywheel. Severe torsional imbalances will result causing
vibration and an unusually high horsepower requirement. The
flywheel should never be replaced by another pulley unless it
is equal to or higher than the wk2 value of the flywheel.
Humid climates can cause problems with explosion
proof motors. The normal breathing of the motor and
alternating temperatures—warm when running and cool
when stopped—can drawn moist air into the motor.
As the moist air condenses, it can build up and cause
motor failure. To prevent this, make a practice of running
the motor at least once a week on a bright, dry, day for
an hour or so without the V-belts attached. During this
period of time, the motor will heat up and vaporize the
condensed moisture. NOTE: No motor manufacturer
guarantees an explosion proof or totally enclosed (TEFC)
motor against damage from moisture.
When installing an engine driver, carefully review the
instructions from the manufacturer and ensure the
engine 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 5.5 for the proper oil filling location).
Compressor
Model
Approximate
Quarts Capacity Liters
791, 891 7.0 6.6
Figure 2.6A: Oil capacity chart.
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
challenging for a Corken compressor user to select a
suitable crankcase oil. This guide is intended to aid in
that regard.
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 most economic 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.
7

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
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.
Figure 2.6B: Oil selection chart.
8

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 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
T “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
O“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.
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)
9

• 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.
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 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.
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