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Cylinder Drain Oil Service
Sampling & Analysis
Quick Start Guide
Overview
Cylinder oil in a main engine has two main tasks. It
should lubricate the engine to have an acceptable
low wear level and it has to neutralize the sulphuric
acid to avoid unexpected acid corrosion in the liner.
By analysing scrapedown oil collected from the scavenge
space shipboard personnel are able to monitor the
condition of the engine’s cylinders and detect changes
as they occur. CMT´s Scrapedown Oil Analysis package
provides comprehensive testing and analysis of the oil
sample, and offers onboard testing tools that enable ship’s
engineers to quickly detect substantial changes in cylinder
condition. It offers a technically advanced approach to
safely optimizing cylinder oil feed rates.
The CMT Cylinder Drain Oil Service does consist of two
important major components:
•
Frequent onboard oil tests of the total iron content
and the alkalinity reserve by testing the BN (base
number). These parameters need to be tested in each
individual unit.
•
Periodical onshore independent laboratory oil tests
providing complete results about wear, contamination,
oil condition and additives together with a diagnostic
statement from our tribology experts.
CDO BN Test
CMT SDA laboratory report page 1
CDO Iron Test
Onboard testing, using the CMT Drain Oil Analysis Test Kit, provides quick, on-site results of the oil’s most important
properties relative to the engine’s cylinder operating condition. The Laboratory oil test does provide a complete overview
about wear, contamination, oil condition and additive components combined with a diagnostic statement.
On board oil tests are designed to measure only single parameters. Use them as a essential supplement to the
Laboratory Oil Test - not as a substitute. A comprehensive laboratory oil analysis together with the frequent
onboard test is essential as part of an effective cylinder drain oil monitoring.
How to do the Sampling
Most modern two stroke engines have already mounted sampling valves on
the drain pipe. Please make sure to not mix up the drain pipe for the waste
oil from the underpiston space with any other drain pipe like for example the
stuffing box etc.
In case there is no sampling valve installed you need to install one to use
the service. This is normally a simple job and can be done onboard during a
normal port stay. Please use the pictures on the right side as an example for
differnt installations.
•
Cylinder drain oil should be sampled during stable engine running
conditions and preferably not during manoeuvering or very short trips
between ports.
•
The sample should be taken directly from the scavenge air drain on each
unit and not from the stuffing box drains or the scavenge air diaphragm
plate.
•
Close the main drain valve from the scavenge air drain.
•
Open the sampling valve for a moment to blow out any oil or sludge
remaining in the sampling valve and dispose of it.
•
Keep the valve closed until enough oil has been collected to allow sampling.
•
Open the sampling valve again briefly to drain off a small amount of oil
into a separate container and dispose it.
•
Take a sample direct into the respective sample bottle and mark it clearly
with the cylinder number.
•
Please make sure you use the sample bottles for the laboratory oil test
(marked with prepaid analysis) only for the laboratory oil test to avoid
extra cost.
•
For the onboard test please use standard sampling bottles.
•
Open the main drain valve again and make sure the sampling valve is
closed properly.
Note: When, where and how you sample has an impact on the quality
of your results. Low quality samples can not give represntative results.
Always follow the same sampling procedure to avoid falsifying the
trend of the measurements.
CDO Sampling Section:
In some cases the cylinder oil takes the form of a mistlike vapour in the drain
pipe which makes it difficult to sample. For those engines CMT does provide
a CDO Sampling Section allowing the oil to “condensate” on the deflector
plates. This allows easy and reliable sample taking. The CDO Sampling Section is
supplied as a flange section and can also be used in all other engines.
Recommended Sampling and Testing Frequency
By analysing scrape down oil collected from the scavenge space shipboard personnel are able to monitor the
condition of the engine’s cylinders, avoid corrosive or abrasive wear by initiating corrective actions and detect
changes as they occur.
CMT has a lot of experience with oil condition monitoring for marine diesel engines. Based on that, we will
give you some recommendation for the sampling and testing frequencies. Unless advised differently by your
superintendent or the engine manufacturer we recommend the following sampling and testing intervals.
Onboard Oil Test:
Laboratory oil test:
Minimum frequency once per week. For a closer look during any changes CMT recommends a daily test of the base
number (BN) and total iron content. This is essential during
feed rate adjustments.
We recommend a quarterly test (or every 1000 - 1500 running hours) under normal running conditions. If there are
unusual results in the laboratory report we might recommend a repeat test after a shorter period. It is advisable to
follow the recommendation.
If your sampling frequency is once per week an additional
sample should be taken after each fuel change to get an
early indication about cat fines. This is most important for
any change between low and high sulphur fuel.
Initate an additional test immediately when onboard test
results deviate decisively from the earlier recorded trend.
80%
70%
60%
50%
40%
30%
20%
10%
0%
Piston Rings
Manpower
Pistons
Cylinder Liners
Cylinder Oil
On-Site Drain Oil Analysis Kit
While in the past abrasive wear was
the predominant wear meachnism
creating problems like scuffing or
sudden severe wear these days corrosive
wear has become the predominant
wear in the new generation of engines,
whereas abrasive wear is no longer
the predominant problem for the new
generation of engines.
Main parameters influencing the
corrosive wear in the combustion
chamber are the sulphur in the fuel,
part load optimisation such as T/C-cut
out, the load pattern and naturally the
lubrication rate and the BN level of the
cylinder oil. The corrosive wear will be
indicated by the BN values and the iron
content of the drain oil from the cylinder
lube oil.
Sulphuric acid forms during the
combustion of sulphur containing fuels.
The sulphuric acid may condensate on
the cylinder liner wall depending on
the temperature of the wall and the
pressure in the cylinder. The higher the
pressure during combustion the lower
is the dew point. In modern high p(max)
engines the dew point of sulphuric acid
may be as high as 280°C leading to a
higher amount of acid condensation
compared to an older design low p(max)
engine with the same fuel consumption.
The measured BN in the drain oil is an
indication of the oils remaining ability
to neutralise this acid. A low BN value
indicates that the oils alkalinity reserve
is close to exhaustion and therefore
cannot protect the engine from the
acid. The concentration of iron particles
in the oil is composed of the abrasive
wear and the corrosive wear. It is
important to monitor both parameters,
BN and iron content closely to avoid
damage to the cylinder liner.
By analysing scrape down oil collected
from the scavenge space you are able
to monitor the condition of the engine’s
cylinders, avoid corrosive or abrasive
wear by means of launching corrective
actions and detect changes as they
occur.
The Cylinder Drain Oil Analysis Set
consists of two different tests:
•
Analysis of the total iron content
(corrosive and abrasive)
•
Analysis of the remaining alkalinity
reserve compared to the fresh oil
alkalinity.
Both tests needs to be done with a
sample from each individual cylinder.
Shake the sample before measuring to
ensure wear debris is evenly distributed.
Measure immediately after you have
taken all samples from each individual
unit.
On board oil tests are designed to
measure only single parameters. Use
them as a essential supplement to the
Laboratory Oil Test - not as a substitute.
A comprehensive laboratory oil analysis
together with the frequent onboard
test is essential as part of an effective
cylinder drain oil monitoring.
Feed Rate Optimization
Optimization means reducing to the
minimum level which still ensures
good lubrication and at the same time
sufficient neutralisation of combustion
related acids. Minimum level also
means having enough oil to clean the
piston surface. Even current standard
electronic lubrication systems are based
only on experience and standard inputs
as rpm or the sulphur level of the fuel.
Engines are regularly over lubricated in
an attempt to avoid problems including
scuffing, but this practice not only
causes high lubrication costs, it can
sometimes lead to associated problems
such as bore polishing. Therefore,
although optimising cylinder lubricant
usage is one method of achieving
commercial advantage, there is a
point where savings can be eroded by
increased maintenance costs.
Laboratory Drain Oil Service
The CMT Cylinder Drain Oil Service will provide you with major information about engine performance and condition. To achieve the maximum
benefit from your laboratory oil analysis it is important to monitor the
trend and the level or the readings. The combination of both, the trend
and the level status will determine an overall equipment and lubricant
condition indicator.
While the onboard analysis will provide a trend of your iron readings and your
alkaline reserve in short intervals the laboratory oil test will show a detailed long
term trend.
The laboratory analysis does give you a trend for all readings but in much longer
intervals. On the report you will find the current reading together with the previous 3 readings.
A full history can be obtained from our web server including a graphical analysis
and also a comparison between different cylinders or vessels etc.
Above the table you will find the diagnosis for the current sample. It is important to read and understand this because it will give you some advice in case we
have found abnormal results.
You will get a detailed lab report
completed with a very detailed
diagnostic statement prepared by
a mechanical engineer. Presented
as a one page report per sample
rated by an easy to understand
system it will quickly alert you of
any problems concerning your oil
or equipment.
There is no need for you to work
through a long report of several
pages. The report contains a historical
look at the last 4 samples with the
complete history available from our
web server (including trend graphs). If
you have any questions relating your
report or equipment you can call one
of our service engineers to discuss
your results and provide advice. The
lab report will be sent to you by mail,
email or fax as agreed with you. The
service includes the following:
•
•
•
•
You can also find your lab report on the Internet:
•
It is possible to get the current lab
reports even faster and to have, at
the same time, a comparison with
earlier analysed samples.
If you require your results sooner,
instead of waiting for an e-mail, fax or
mail you can directly log on to our fire
wall protected web server.
As soon as we have evaluated your
sample, will inform you by e-mail that
the results are available.
You can see the analysis results in
the original version of the lab report
and print it or forward it to interested
parties.
This service offers you to:
•
•
•
•
•
•
•
•
•
•
Easily check online data entry for
new samples
Quickly view of all your samples
Check sample status
Display all lab reports
Translate lab reports into different
languages
Forward lab reports via e-mail
Graphically view trend analysis
values for individual samples
Display of the IR spectrum and
other diagrams
View photos of the sample and the
inside of the cap / lid
View photos of the spot test, solid
contaminants and much more
•
•
100 ml sample-bottle (prepaid)
Addressed envelope to return the
sample bottle to our lab
Sample Information Form with
barcode label
Laboratory tests: All samples are
analysed and diagnosed by the
end of the next business day.
(As long as the samples arrive
at our laboratory before noon,
in our prepaid sample bottle
with a correctly filled out sample
information form).
Laboratory report complete
with a highly detailed diagnostic
statement (prepared by a
mechanical engineer)
Dispatch of the laboratory report
via mail, email, fax or data-file
Online-recall of all laboratory
reports and analysis data
Quelle: Oelcheck GmbH
How to do the Laboratory Oil Test
After taking the sample make sure to add the correct sample
information form to the bottle. It is important to fill out the
sample information form correctly. The section on the right
side is reserved specially for the cylinder drain oil.
•
•
•
•
•
•
•
•
•
•
•
Fill out the sample information form.
Fill in the additional information for cylinder drain oil.
As machinery code use C1 for the sample from cylinder
1 and C(n) for cylinder n.
Fill in the results from the onboard test device in the
relevant section.
Remove the barcode sticker from zhe sample information form and place it on the bottle.
Put the corresponding Sample Information Form into
the transparent plastic bag on the top of the envelope
to avoid oil spots on the form.
Add your last bunker oil analysis if available.
Put each sample bottle in one separate pre-addressed oil
proof plastic envelope. (The adhesive flap securely closes
the envelope)
Put all samples together and ship to the address mentioned on the individual envelopes.
For shipping purposes please use the Proforma invoice
on the next page as example.
The results of your laboratory oil test will be sent to your
office usually 24 hours after receipt of the sample in the
lab. (If the sample arrives before 12:00 clock)
CMT SDA laboratory report page 3
CMT SDA laboratory report page 2
CMT SDA laboratory report page 4
Pro-Forma Invoice
Consignee:
OELCHECK GmbH
Kerschelweg 28
83098 Brannenburg
Germany
Goods:
Used cylinder oil samples from diesel engine
Content not restricted according GGVSE / ADR / RID;
IATA / DGR; GGVSee / IMDG.
Value:
No commercial value. ($1.00)
Inco terms:
DDP incl. VAT
(This section to be completed by ships staff)
Samples forwarded by:
Ships name:
Port where samples landed:
Country where samples landed:
Date samples landed:
(This section to be completed by ships agent)
Consignors name
Consignors address
Consignors phone number
Consignors Signature
Interpreting Results
Below you will find further explanations about the
readings from your on-site devices as well as for
the qualified laboratory oil analysis report. For any
further questions regarding the results from the onsite laboratory oil test our technical experts would
be pleased to assist you.
Iron Level: Is, beside the base number, the most important indication for any problem in the liner. It can indicate
corrosive or abrasive wear. Corrosive wear is caused by
acid condensation on the liner wall. Abrasive wear
happens because of liner or ring wear. The reading from
your on-board device might be different from your laboratory oil report. This is not because of inaccuracy of either
device but because of the different measuring methods.
The lab measures the chemical element Fe with either
ICP or XRF. The results are being reported as Iron. This
will also report any iron which is chemically bounded like
corrosion. On the other hand ICP will not show particles
bigger than 5 µm but XRF will. Therefore it is important
to understand which method is used in the lab. In most
labs (also in the CMT lab) the ICP method is used which
will only measure smaller particles. In many labs the PQ
method is being used in addition. This method is based
on a magnetometry principle which will detect only the
abrasive wear. Corrosive wear metal is no longer magnetic
and cannot be seen when this principle is being applied.
However, it allows seeing also large particles so that it is a
useful addition to the ICP method .
For onsite testing purposes there are different devices
available. The CMT device similar to the Chevron DOT.
FAST ® device will see the total iron content (abrasive and
corrosive). This method is therefore recommended by MAN
and Wartsila. The advantage of the CMT device is that it
will give separated readings for abrasive and corrosive iron
with on test. There are also other on-site devices on the
market like the Mobile Scrapedown Analyser (MSA) or the
Shell (or Kittiwake) Analex Alert. Those devices are based
on magnetomety similar to the PQ technology in the lab
which will see only the abrasive wear. The corrosive wear,
which is these days of much more concern, cannot be
measured with with this technology.
Base Number: Is a very important indication for corrosive
wear because of the acid condensation. The acid will condense at the liner wall when the temperature gets below
the dew point of the acid. In modern engines this can
happen already at temperatures around 280 °C during the
combustion process. Also slow steaming does reduce the
temperature to a point, where cold corrosion can happen.
BN values can vary between units due to different fuel injection, higher cylinder pressure or lower liner wall temperature. Also system oil leakage will reduce the BN reading
in the under piston space.
During the combustion process the sulphur in the fuel and
the moisture in the air will form sulphuric acid. This acid
needs to be neutralised by the additives in the cylinder
oil. The amount of additives is indicated by the BN (base
number) of the fresh oil. A critical low BN level in the drain
oil can result in acidic corrosion whereas a very high BN
level will result in deposits creating abrasive material. An
optimal BN value will be around 25 mg KOH/g. Please
make sure that the BN in your cylinder drain oil is always
above 15 mg KOH/g as minimum.
Soot: A high soot level indicates
an unstable combustion. Soot level
should be below 0.3% during normal
operation.
The soot level can go up to 5 % and
higher. In these cases a blow by is likely. Otherwise a bad combustion can
be the reason for high soot readings.
With the CMT Diesel Performance
Analyser the performance of the combustion can be checked.
For soot test CMT does provide a simple electronic soot test meter.
Dispersancy: High readings indicate
that the cylinder oil is contaminated
with fuel and lubricant debris. It is
important to have an adequate dispersant reserve to maintain piston
cleanliness.
Interpreting Results
Water: Water in the cylinders is present because of the
humidity of the inlet air. Most of it should be collected
by the water catchers. However, in high humidity areas
sometimes the water mist catchers cannot cope with the
amount of water in the air. It can also indicate a possible
cooling water leakage. If the air cooler does run with sea
water the sodium reading will be high as well. The water
level should stay below 0.5% water. High water levels
may be causing emulsification and disruption of cylinder
lubrication. It will increase the viscosity of the lube oil and
contribute to wear. In case of an increased water content
we recommend that the air coolers and water catchers
serving the respective units are inspected and drains are
checked for obstructions in order to eliminate further water ingress. Sampling procedures should be followed carefully as incorrect sampling can cause a high water content
in the oil sample which is not an indication for unusual
water ingress into the combustion space. Note that prior
to sampling the first liquid from the sampling cock should
be drained as water may accumulate in the line.
Sodium / Manganese: If the sodium and the water levels
are elevated it would be an indication for seawater. If there
is seawater present usually the Manganese value would
be increased as well. In case of a seawater ingress Sodium
and Manganese should be present in a 1:5 ratio. However,
cooling water leakage into the cylinder drain oil is not seen
very often.
Aluminium and Silicon: Is an indication of a high cat
fines level in the fuel. High cat fines are causing abrasive
wear. High iron readings would be a proof for this. According to ISO 8217 fuel must have a cat fines level below 80
ppm when delivered.However, the engine manufacturers
specify cat fines levels of about 15 ppm and below when
the fuel is injected into the engine. High cat fines levels in
the drain oil indicate an inadequate performance of the
fuel oil separators.
Viscosity: An increased viscosity is an indication of contamination with water and / or unburned fuel possibly
caused by blow by. Tin: Low values combined with low
iron indicate normal free movement of the piston and that
abrasion between piston skirt and liner wall is insignificant.
High levels point to a disturbance of the piston alignment.
Higher levels are expected during running in. Tin levels up
to 20 ppm are normal.
Nickel / Vanadium: Is an indication of fuel contamination
because of blow by. You should also see an increased viscosity value. Vanadium levels around and above 300 ppm
indicate a possible blow by.
Chrome: Elevated Chromium content indicates wear of
the piston ring groove coating. Levels below 10 ppm are
within normal range. Higher levels are expected during
running in.
Copper: Higher levels are an indication of skirt and / or
stuffing box wear. In case of alu-coated rings the level will
also be higher during running in of new rings.
Dispersancy: High readings indicate that the cylinder oil is
contaminated with fuel and lubricant debris. It is important
to have an adequate dispersant reserve to maintain piston
cleanliness.
Zinc and Phosphorus Level: Is an indication of system
oil leakage through the stuffing box into the scavenge air
space. Zinc levels up to 30 ppm are within normal range.
For any questions regarding your results please contact our experts for further advice or send an email
to: [email protected]
Spares and Consumables
Following spare parts and consumables are available from CMT. Please contact your local CMT representative or use the
contact details on the last page to order the parts.
LAB-CT-17601
SDA Drain Oil Analysis
(use only for laboratory analysis)
No. of analysis:
1 pre-paid bottle
SAM-CT-70250
120 ml Sample Bottles (250)
(for general onboard use)
Neck:
38 mm
Material:
PETG
SAM-CT-70360
50 ml Sample Bottles (360)
(for general onboard use)
Neck:
28 mm
Material:
HDPE
OTS-CT-13024
Iron Test Reagent Pack
No. of Tests:
50
Reagents:
non hazardous
OTS-CT-13029
Iron Glass Tubes Pack (for serial no. > 400)
Glass Tubes
100
OTR-CT-12002
Base Number Reagent Pack
No. of Tests:
50
Reagents:
non hazardous
OTR-CT-11000
Test Kit Cleaner (250 ml)
OTS-CT-13027:
Spare BN CDO TestCell
OTS-CT-13026
Spare Iron PhotoCell
OTS-CT-13005
Battery for Test or PhotoCell
CM Technologies GmbH
Marie-Curie-Str. 5
25337 Elmshorn Germany
Tel: +49 (4121) 700890
Email: [email protected]
Web: www.CMTechnologies.de
DO-C10061-CT – issue 5