ISO 23820:2023

INTERNATIONAL ISO
STANDARD 23820
First edition
2023-05
Determination of the filtration
efficiency of urea filter modules
Détermination de l'efficacité de filtration des modules de filtres à urée
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Test procedures . 3
5.1 Principle . 3
5.2 Test equipment and materials . 4
5.2.1 Test rig . 4
5.2.2 Filter test circuit . 4
5.2.3 Contaminant injection circuits . 5
5.2.4 Automatic particle counting devices . 6
5.2.5 Test fluid . 6
5.2.6 Test contaminant . 6
5.2.7 Stop watch . 6
5.2.8 Ultra clean bottles . 6
5.2.9 Ultra-sonic bath . 6
5.3 Test rig validation . 6
5.3.1 General . 6
5.4 Procedure . 9
5.4.1 Operating conditions . 9
5.4.2 Preparation of the contaminant injection circuits . 10
5.4.3 Preparation of the test circuit . 11
5.4.4 Filter efficiency and retention capacity test . 11
5.5 Expression of results . .13
5.6 Test report . 13
Annex A (informative) Determination of the initial filtration efficiency as per this
document .15
Bibliography .21
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain and powertrain fluids.
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iv
INTERNATIONAL STANDARD ISO 23820:2023(E)
Determination of the filtration efficiency of urea filter
modules
1 Scope
This document specifies requirements relating to the testing method for AUS 32/diesel exhaust fluid
(DEF) filters for the removal of suspended matter. This applies to urea filters dedicated to passenger
vehicles as well as to commercial vehicles. This method applies to filters with flow rates from 3 l/h to
30 l/h depending on the application (by default 5 l/h for passenger vehicles and 25 l/h for commercial
vehicles). This method can be used for other flow rates, provided the validation requirement can be
met.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 11218, Aerospace — Cleanliness classification for hydraulic fluids
ISO 11923, Water quality — Determination of suspended solids by filtration through glass-fibre filters
ISO 21501-3, Determination of particle size distribution — Single particle light interaction methods — Part
3: Light extinction liquid-borne particle counter
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
cumulative overall mean filtration efficiency
E
x
cumulative efficiency calculated from the total number of particles greater than size x [µm] counted
upstream and downstream of a filter during the initial 60 min counting period at 5 mg/l
Note 1 to entry: The efficiency is expressed in [%].
3.2
differential pressure
ΔP
pressure difference between the inlet and outlet of the complete filter unit measured under
predetermined conditions
Note 1 to entry: The differential pressure generated by the complete filter is equal to the sum of the differential
pressures generated by the housing and by the filter element (in case the filter element is removable from the
housing).
Note 2 to entry: The differential pressure is expressed in kPa.
3.3
ISO MTD
ISO medium test dust
siliceous test powder having a particle size distribution by volume in accordance with ISO 12103-1, A3
Note 1 to entry: It may also be referred as ISO 12103-1 A3 dust.
3.4
nominal flow rate
Q
flow rate for the filter specified by the manufacturer
Note 1 to entry: The flow rate is expressed in l/h.
3.5
reference filtration rating
S
dimension of the ISO MTD particles at which the overall mean cumulative filtration efficiency of
the integral filter (or the filter element) tested in accordance with the procedure described in this
document, is greater than or equal to 99 %
Note 1 to entry: The reference filtration rating is expressed in µm.
4 Symbols
The symbols used in this document are given in Table 1.
Table 1 — Symbols
Symbol Parameter Unit
C Test concentration mg/l
e
C Injection concentration mg/l
i
C Retention capacity g
R
C Concentration of the downstream fluid during the clogging
NR
mg/l
period
C Coefficient of variation %
ov
d Size of the particle μm
ΔP Loss of pressure due to the clean filter alone kPa
ΔP Loss of pressure at the end of the test kPa
F
E Cumulative efficiency at size greater than x µm %
x
M Mass of contaminant necessary for the test g
M Injected mass of contaminant in injection reservoir 1 g
i1
M Injected mass of contaminant in injection reservoir 2 g
i2
th
N > x µm i particle count upstream at size >x µm -/ml
i UP
th
N > x µm i particle count downstream at size >x µm -/ml
i DW
Q Flow rate l/h
Q Recirculation flow rate l/h
r
Q Injection flow rate circuit 1 (relative to the efficiency con-
C1
l/h
centration)
Q Injection flow rate circuit 2 (relative to the capacity con-
C2
l/h
centration)
S Suspended solid concentration mg/l
sc
V Injection circuit N°1 fluid volume l
i1
TTaabblle 1 e 1 ((ccoonnttiinnueuedd))
Symbol Parameter Unit
V Injection circuit N°2 fluid volume l
i2
V Injection circuit maximum fluid volume l
iM
V Recovered downstream volume during the clogging period l
CP
V Recovered downstream volume during the validation of
CPV
l
the clogging period
ΔT Time duration of the clogging period h
CP
5 Test procedures
5.1 Principle
The performance of the filter to be tested is determined by measuring its hydraulic and separative
properties when subjected to a constant flow rate of water conveying a known quantity of contaminant.
The test is performed with the water after passage through clean-up filters to produce a single pass
configuration. The test is conducted in two stages.
The first stage determines the initial efficiency of the test filter. It is conducted with a contaminant
concentration of 5 mg/l upstream to the test filter for 60 min. The second stage determines the mass of
contaminant needed to reach a specified differential pressure. This stage is conducted with an upstream
concentration of 800 mg/l, or as specified according to the customer specification. The retention
capacity shall be determined from the mass of contaminant required for obtaining a predetermined
differential pressure of 10 kPa o
...