ISO 19438:2003
(Main)Diesel fuel and petrol filters for internal combustion engines — Filtration efficiency using particle counting and contaminant retention capacity
Diesel fuel and petrol filters for internal combustion engines — Filtration efficiency using particle counting and contaminant retention capacity
ISO 19438:2003 specifies a multi-pass filtration test, with continuous contaminant injection and using the on-line particle counting method, for evaluating the performance of fuel filters for internal combustion engines submitted to a constant flow rate of test liquid. The test procedure determines the contaminant capacity of a filter, its particulate removal characteristics and differential pressure. ISO 19438:2003 is applicable to filter elements having a rated flow of between 50 l/h and 800 l/h; however, by agreement between filter manufacturer and customer, and with some modification, the procedure is permitted for application to fuel filters with higher flow rates.
Filtres à carburant, essence ou diesel, pour moteurs à combustion interne — Efficacité de filtration par comptage des particules et capacité de rétention
General Information
Relations
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 19438
First edition
2003-11-01
Corrected version
2004-06-15
Diesel fuel and petrol filters for internal
combustion engines — Filtration
efficiency using particle counting and
contaminant retention capacity
Filtres à carburant, essence ou diesel, pour moteurs à combustion
interne — Efficacité de filtration par comptage des particules et capacité
de rétention
Reference number
ISO 19438:2003(E)
©
ISO 2003
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ISO 19438:2003(E)
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ii © ISO 2003 — All rights reserved
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ISO 19438:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols . 2
5 Test equipment and materials . 2
5.1 Test equipment. 2
5.2 Test materials . 5
6 Accuracy of measuring instruments and test conditions . 5
7 Test rig validation . 6
7.1 General. 6
7.2 Validation of the on-line dilution and particle counting system . 6
7.3 Validation of filter test circuit . 6
7.4 Validation of contaminant injection circuit . 7
8 Preliminary preparation. 7
8.1 Test filter assembly. 7
8.2 Contaminant injection circuit . 7
8.3 Filter test circuit . 9
9 Test procedure . 9
9.1 Initial procedure . 9
9.2 Filter test . 11
10 Calculation and reporting of test results. 12
10.1 Test report . 12
10.2 Calculation. 12
Annex A (normative) Specification of test fluid for filter test . 15
Annex B (informative) Typical filter test report, presentation of test results. 17
Annex C (informative) Example filter efficiency calculations . 22
Annex D (informative) Summary of the International interlaboratory trial (“round robin”) to
validate ISO 19438 protocol . 26
Bibliography . 38
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ISO 19438:2003(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 19438 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 7, Injection
equipment and filters for use on road vehicles.
It is intended that ISO 19438 replace ISO/TS 13353:2002 when that document is reviewed after three years.
This corrected version of ISO 19438:2003 incorporates the following corrections:
in the test report in Annex B, under the headings “Presentation of test results… Initial filtration efficiency
— Elapsed time: 6,00 min…” and “… Initial filtration efficiency — Elapsed time: 15,00 min…”, the particle
size “W 3 µm(c)” has been corrected to "W 13 µm(c)”;
in Figure D.4, the curve labelled at left of the legend as “LATOUR T2” has been corrected to read
“LATOUR T1”;
an explanation that the barred values in the table are discarded outliers has been inserted in the title of
Table D.2;
ISO/TS 13353 has been added to the bibliography;
typographical errors have been corrected.
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ISO 19438:2003(E)
Introduction
An interlaboratory trial was conducted using ISO 19438 by six laboratories in 2002. Typical filters were
evaluated and results for filtration efficiencies and retention capacities analysed to deduce repeatability,
reproducibility and coefficient of variation of the method. Initial filtration efficiency results were found to closely
correlate to those obtained through the method specified in ISO/TS 13353, thus making the method given in
that Technical Specification redundant.
A summary of the results is given in Annex D.
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INTERNATIONAL STANDARD ISO 19438:2003(E)
Diesel fuel and petrol filters for internal combustion engines —
Filtration efficiency using particle counting and contaminant
retention capacity
1 Scope
This International Standard specifies a multi-pass filtration test, with continuous contaminant injection and
using the on-line particle counting method, for evaluating the performance of diesel fuel and petrol filters for
internal combustion engines submitted to a constant flow rate of test liquid. The test procedure determines the
contaminant capacity of a filter, its particulate removal characteristics and differential pressure. This
International Standard is applicable to filter elements having a rated flow of between 50 l/h and 800 l/h;
however, by agreement between filter manufacturer and customer, and with some modification, the procedure
is permitted for application to fuel filters with higher flow rates.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1219-1:1991, Fluid power systems and components — Graphic symbols and circuit diagrams — Part 1:
Graphic symbols
ISO 2942:1994, Hydraulic fluid power — Filter elements — Verification of fabrication integrity and
determination of the first bubble point
ISO 3968:2001, Hydraulic fluid power — Filters — Evaluation of differential pressure versus flow
characteristics
ISO 4021:1992, Hydraulic fluid power — Particulate contamination analysis — Extraction of fluid samples from
lines of an operating system
ISO 11171:1999, Hydraulic fluid power — Calibration of automatic particle counters for liquids
ISO 4405:1991, Hydraulic fluid power — Fluid contamination — Determination of particulate contamination by
the gravimetric method
ISO 11841-1, Road vehicles and internal combustion engines — Filter vocabulary — Part 1: Definitions of
filters and filter components
ISO 11841-2, Road vehicles and internal combustion engines — Filter vocabulary — Part 2: Definitions of
characteristics of filters and their components
ISO 11943:1999, Hydraulic fluid power — On-line automatic particle-counting systems — Method of
calibration and validation
ISO 12103-1:1997, Road vehicles — Test dust for filter evaluation — Part 1: Arizona test dust
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ISO 19438:2003(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11841-1 and ISO 11841-2 and the
following apply.
3.1
multipass test
test which requires the recirculation of filtered fluid through the filter element
3.2
base upstream gravimetric level
upstream contaminant concentration if no contaminant is recirculated
3.3
filtration efficiency
ability of the filter to retain particles expressed as the percentage of particles of a given size retained by the
filter under test
3.4
overall efficiency
efficiency calculated from the average upstream and downstream particle counts obtained during the entire
test
3.5
filter rating
particle size corresponding to an initial efficiency or cumulative overall efficiency of a given percentage
NOTE It is expressed in micrometres(c) [µm(c)], which signifies throughout this International Standard that a particle
size measurement is carried out using an automatic particle counter calibrated in accordance with ISO 11171.
3.6
filter reference rating
filter rating at 99 % efficiency
NOTE It is expressed in micrometres(c) [µm(c)], which signifies throughout this International Standard that a particle
size measurement is carried out using an automatic particle counter calibrated in accordance with ISO 11171.
3.7
initial efficiency
efficiency at first data points calculated from 4 min, 5 min and 6 min particle counts
4 Symbols
Graphical symbols used in this International Standard for fluid power system components are in accordance
with ISO 1219-1.
5 Test equipment and materials
5.1 Test equipment
5.1.1 Test rig
The test rig, shown diagrammatically in Figure 1 (to which the numbers in parentheses throughout this
International Standard refer), shall comprise the following.
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ISO 19438:2003(E)
5.1.1.1 Filter test circuit, including the components specified in 5.1.1.1.1 to 5.1.1.1.7.
5.1.1.1.1 Reservoir (1), constructed with a conical bottom having an included angle of not more than 90°
and where the oil entering is diffused below the fluid surface.
5.1.1.1.2 Oil pump (2), which does not alter the contaminant particle size distribution and does not exhibit
pressure pulsation with an amplitude greater than 10 % of the average pressure at the filter inlet.
5.1.1.1.3 Device, such as a filter head to accommodate spin-on filters, which connects the test filter (6) and
which can be by-passed or replaced by a straight section of pipe.
5.1.1.1.4 System clean-up filter (9), capable of providing an initial system contamination level of less than
15 particles/ml having a size greater than 10 µm(c).
5.1.1.1.5 Sampling valves, in accordance with ISO 4021, for turbulent sampling upstream and
downstream of the test filter, for on-line particle counting (18) and for gravimetric analysis (11).
5.1.1.1.6 Pressure tappings, in accordance with ISO 3968.
5.1.1.1.7 Piping, sized to ensure that turbulent mixing conditions exist throughout the filter test circuit.
5.1.1.2 Contaminant injection circuit, including the components specified in 5.1.1.2.1 to 5.1.1.2.3.
5.1.1.2.1 Reservoir (12), constructed with a conical bottom having an included angle of not more than 90°
and where the oil entering is diffused below the fluid surface.
5.1.1.2.2 Oil pump (13), of centrifugal or other type, which does not alter the contaminant particle size
distribution.
5.1.1.2.3 System clean-up filter (14), capable of providing either of the following conditions:
a) an initial system contamination level of less than 1 000 particles/ml having a size greater than 10 µm(c);
b) a gravimetric level less than 2 % of the calculated level at which the test is being conducted, measured
using the double membrane gravimetric method in accordance with ISO 4405.
5.1.1.2.4 Piping, sized to ensure that turbulent mixing conditions exist throughout the contaminant injection
circuit.
While injection flows lower than 0,25 l/min may be used if validated, an injection flow of 0,25 l/min is
recommended.
Injection flows higher than 0,25 l/min shall not be used to minimize the effect of fluid extraction on filter
capacity.
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ISO 19438:2003(E)
Key
1 reservoir incorporating thermostatically controlled heater 13 circulation pump A contaminant injection
circuit
2 test pump 14 clean-up filter
3 three-way ball valve 15 heat exchanger B filter test circuit
4 pressure gauge 16 injection pump C dilution and counting
system
5 differential pressure gauge 17 flow meter
6 test filter 18 sampling valve
7 throttle valve (for flow regulation) 19 dilution system
8 flow meter 20 particle counter sensor
9 clean-up filter 21 particle counter
10 heat exchanger 22 sampling valve
11 sampling valve 23 by-pass flow circuit
12 reservoir incorporating thermostatically controlled heater
Figure 1 — Diagrammatic arrangement of test rig
5.1.2 On-line dilution and particle counting system
The on-line dilution and particle counting system shall be in accordance with ISO 11943 and include the
components specified in 5.1.2.1 to 5.1.2.4.
5.1.2.1 On-line sample delivery pipework, sized to maintain a fluid velocity that prevents silting at a
flow rate of 0,125 l/min. For tests with sampling flows > 10 % of the total filter flow rate, the amount of dust
discarded in the sampling flow will be significant. This amount shall be evaluated and deducted from the
retained capacity. Lower flow rates may be used provided they are validated.
5.1.2.2 Dilution system (19), comprising appropriate reservoir, pump, clean-up filters, flow meters and
flow regulation valves.
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ISO 19438:2003(E)
5.1.2.3 Two optical particle sensors (20), connected to a particle counter (21) having a minimum of five
channels.
5.1.2.4 Timer, capable of measuring minutes and seconds.
5.2 Test materials
5.2.1 Test contaminant
5.2.1.1 Contaminant grade
The contaminant shall be in accordance with the specification of ISO 12103-A3 medium grade test dust.
5.2.1.2 Contaminant preparation
The test dust shall be pre-dried in quantities no larger than 200 g for at least 1 h at (105 ± 5) °C and cooled to
room temperature. Maintain in a desiccator until required for use.
5.2.2 Test fluid
The test fluid shall have a petroleum base and conform to the specifications given in Annex A.
6 Accuracy of measuring instruments and test conditions
The measuring instruments shall be capable of measuring to the levels of accuracy given in Table 1. The last
column in the table gives the limits within which the test conditions shall be maintained.
Table 1 — Instrument accuracy and test condition variation
Test condition Unit Measurement accuracy Allowed test condition variation
Flow
Filter Test Flow l/min
± 2 % ± 5 %
Sampling Flow ml/min
± 1,5 % ± 3 %
Injection Flow ml/min
± 2 % ± 5 %
Pressure Pa —
± 5 %
Temperature °C ± 1 °C 2 °C
Volume l ± 5 % ± 10 %
mg/l —
Base upstream gravimetric level ± 10 %
Conductivity pS/m See 8.3.4
± 10 %
a 2
mm /s ± 5 % —
Viscosity
a
The viscosity of the test liquid should be checked at regular intervals to ensure that the test is conducted at a liquid temperature
2
which corresponds to a viscosity of 15 ± 1 mm /s.
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ISO 19438:2003(E)
7 Test rig validation
7.1 General
These validation procedures reveal the effectiveness of the test rig in maintaining contaminant entrainment or
preventing contaminant size modification or both.
7.2 Validation of the on-line dilution and particle counting system
Proceed in accordance with ISO 11943 to validate the on-line dilution system and in accordance with
ISO 11171 to validate the particle counter.
7.3 Validation of filter test circuit
7.3.1 Validate the filter test circuit at the minimum flow rate at which the circuit will be operated.
7.3.2 Install a straight section of pipe in place of a test filter during the validation procedure.
7.3.3 Adjust the total circuit volume so that it is numerically equal to half the value of the minimum flow
volume per minute through the filter, with a minimum of 6 l. The total circuit volume should include sump,
piping and filter. A by-pass flow loop should be utilized for low flow test conditions.
7.3.4 Contaminate the fluid to the calculated gravimetric level of 5 mg/l using ISO 12103-A3 test dust.
NOTE This contamination level is below the coincidence limit of automatic particle counters.
7.3.5 Circulate the fluid in the test system for 1 h while obtaining downstream cumulative counts at 5 µm(c),
10 µm(c) and 20 µm(c), without on-line dilution, at 10 min sample intervals.
7.3.6 Calculate and record the on-line count (C ) in particles per millilitre, using the equation:
o
N
c
C =
o
V
where
N is the cumulative count for the selected sample period, in number of particles;
c
V is the volume of fluid, in millilitres, passed through the particle counter sensor during the sample
period.
7.3.7 The validation shall be accepted only if
a) each particle count obtained at 5 µm(c), 10 µm(c) and 20 µm(c) does not deviate by more than 10 % from
the average particle count for these sizes,
b) the average for all particles per millilitre at channels W 5 µm(c) is not less than 6 000 and not greater than
7 300,
c) the average for all particles per millilitre at channels W 10 µm(c) is not less than 815 and not greater than
1 015, and
d) the average for all particles per millilitre at channel W 20 µm(c) is not less than 77 and not greater than
106.
7.3.8 Contaminate the fluid to the maximum gravimetric level to be tested using ISO 12103-A3 test dust.
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ISO 19438:2003(E)
7.3.9 Circulate the fluid in the test system for 1 h while obtaining downstream cumulative counts at 5 µm(c),
10 µm(c) and 20 µm(c), with on-line dilution, at 10 min sample intervals.
7.3.10 The validation test shall be accepted only if each particle count obtained at 5 µm(c), 10 µm(c) and
20 µm(c) does not deviate by more than 10 % from the average particle count for these sizes.
7.4 Validation of contaminant injection circuit
7.4.1 Validate the contaminant injection circuit at the maximum volume and the maximum gravimetric level
to be used.
7.4.2 Add the required quantity of contaminant in slurry form to the injection circuit fluid and circulate for a
time sufficient to completely disperse the contaminant.
NOTE All systems might not disperse contaminant at the same rate. A period of 10 min to 20 min could be necessary
for complete dispersion.
7.4.3 Extract fluid samples at the point where the injection fluid is discharged into the filter test circuit
reservoir at 30 min intervals over 2 h and analyse each sample gravimetrically. These samples should be
taken at the intended test injection flow rate.
7.4.4 The validation test shall be accepted only if the gravimetric level of each sample is within ± 5 % of the
average of the four samples and if this average is within ± 5 % of the gravimetric value selected in 7.3.1.
8 Preliminary preparation
8.1 Test filter assembly
8.1.1 Ensure that the test fluid cannot by pass the filter element to be evaluated.
8.1.2 Subject the test filter element to a fabrication integrity test in accordance with ISO 2942:1994 using
MIL-H-5606 fluid prior to the multi-pass test or following it, if the element is not readily accessible as in the
spin-on configuration.
8.1.3 If the integrity test has been made prior to the multi-pass test and if the test filter element fails to meet
the test pressure agreed between the purchaser and the manufacturer, the element shall be disqualified from
further testing. If the integrity test has been made after the multi-pass test and if the element fails, the test
result shall be disqualified.
8.2 Contaminant injection circuit
8.2.1 Using 50 mg/l as the base upstream gravimetric level, calculate the predicted test time, T , in minutes,
e
from the equation:
FF
cc
T==
e
GQ××50 Q
where
F is the estimated capacity of the filter element, in milligrams;
c
G is the base upstream gravimetric level, in milligrams per litre;
Q is the test flow rate, in litres per minute.
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ISO 19438:2003(E)
The test duration should be > 30 min. The base upstream gravimetric level of 50 mg/l should be adhered to
unless otherwise agreed upon by purchaser and manufacturer. Base upstream gravimetric levels up to
100 mg/l may be used to shorten test times, while base upstream gravimetric levels down to 25 mg/l may be
used to lengthen test times, but only the results of filter tests using the same base upstream gravimetric level
may be compared.
NOTE If the estimated capacity of the filter element (F ) is not supplied by the manufacturer, it might be necessary to
c
determine the capacity by testing an element.
8.2.2 Calculate the minimum volume of fluid, V , in litres, required for the operation of the injection circuit,
m
compatible with the predicted test time and an injection flow rate of 0,25 l/min, using the equation:
V = 1,2T × Q + V
m e i o
where
T is the predicted test time, in minutes, in accordance with 8.2.1;
e
Q is the injection flow rate, in litres per minute;
i
V is the minimum volume of fluid in the injection circuit necessary to avoid air entrainment.
o
The calculated minimum volume should ensure a quantity of contaminant fluid sufficient to load the element,
plus 20 % for adequate circulation throughout the test and to avoid entrainment. Larger injection volumes may
be used.
8.2.3 Calculate the gravimetric level, G , in milligrams per litre of the injection fluid, from the equation:
i
ρ ×QQ50
G==
i
QQ
ii
where
G is the base upstream gravimetric level, in milligrams per litre, in accordance with 8.2.1;
Q is the test flow rate, in litres per minute;
Q is the injection flow rate, in litres per minute.
i
8.2.4 Calculate the quantity of contaminant, W, in grams, needed for the contaminant injection circuit, using
the equation:
GV×
ii
W =
1 000
where
G is the gravimetric level, in milligrams per litre, in accordance with 8.2.3;
i
V is the volume of fluid contained in the injection circuit, in litres.
i
8.2.5 Adjust the injection flow rate at stabilized temperature to within ± 5 % of the value selected in 8.2.2
and maintain throughout the test.
8.2.6 Circulate the fluid in the contaminant injection circuit through the clean-up filter (14) until either of the
following conditions are attained:
a) a contamination level of less than 1 000 particles per millilitre having a size greater than 10 µm(c);
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ISO 19438:2003(E)
b) a gravimetric level of less than 2 % of the value calculated in accordance with 8.2.3.
8.2.7 By pass the system clean-up filter (14) after the required initial contamination has been achieved.
8.2.8 Adjust the total volume of the contaminant injection system to the value determined in 8.2.2.
8.2.9 Ensure that the conductivity of the test fluid and the injection fluid is at least 1 000 pS/m by measuring
fluid conductivity prior to each test. A level of 1 500 pS/m ± 500 pS/m should be used. An initial level of
100 ppm of an antistatic agent has been shown to produce conductivity within this range.
8.2.10 Add in slurry form to the contaminant injection circuit reservoir (12) the quantity of contaminant (W)
determined in 8.2.4, and circulate until the contaminant is completely dispersed.
NOTE Complete dispersal of the contaminant can take between 10 min and 20 min.
8.3 Filter test circuit
8.3.1 Install a straight section of pipe in place of the test filter.
8.3.2 Circulate the fluid in the filter test circuit through the clean-up filter (9) until a contamination level of
less than 15 particles per millilitre having a size greater than 10 µm(c) is attained. Record this value as the
initial cleanliness level of the system.
The contamination level should be checked with the on-line particle counting system, which will at the same
time clean the sampling lines.
8.3.3 Adjust the fluid volume of the filter test circuit to the value determined in 7.2.3 and record this value.
8.3.4 Ensure that the conductivity of the test fluid is at least 1 000 pS/m by measuring fluid conductivity prior
to each test. A level of 1 500 pS/m ± 500 pS/m should be used. An initial level of 100 ppm of an antistatic
agent has been shown to produce conductivity within this range.
8.3.5 Install the filter housing, without the test element, in the filter test circuit. For a spin-on type filter,
install this spin-on filter body without an element inside.
8.3.6 Circulate the fluid in the filter test circuit at the rated flow and at the stabilized test temperature
specified in 9.1.1 ± 2 °C. Measure and record the differential pressure, ∆p , of the empty filter housing.
3
8.3.7 Adjust the channels on the particle counter to read the following particle sizes, in micrometres(c).
5 [6] channel counter: [4], 5, 10, 15, 20, 30.
16 channel counter: 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 20, 25, 30, 40, 50.
9 Test procedure
9.1 Ini
...
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