ISO 9912-4:2018

INTERNATIONAL ISO
STANDARD 9912-4
First edition
2018-08
Agricultural irrigation equipment —
Filters for microirrigation —
Part 4:
Granulated media filters
Matériel agricole d'irrigation — Filtres pour micro-irrigation —
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Design and construction requirements . 2
4.1 General . 2
4.2 Inlet and expansion space chamber . 5
4.3 Media chamber . 5
4.4 Collection (underdrain) and back flushing unit . 5
4.5 Prefiltration element. 5
4.6 Back flushing control . 6
4.6.1 Mandatory requirements . 6
4.6.2 Optional features . 6
5 Resistance of the filter to internal hydrostatic pressure . 6
5.1 General . 6
5.2 Preparation . 7
5.3 Static pressure test . 7
5.4 Cyclic pressure test . 7
5.5 Collection (underdrain) and back flushing unit resistance to buckling or tearing . 8
6 Clean pressure drop test . 9
6.1 General . 9
6.2 Flow rates and test sequence . 9
6.3 Filter media . 9
6.4 Prescreening . 9
6.5 Inlet and outlet pressures. 9
6.6 Test duration . 9
6.7 Report .10
7 Back flushing tests .10
7.1 Back flushing parameters .10
7.2 Media escape test .10
8 Automatic back flushing and controller .11
8.1 Back flushing initiation .11
8.2 Flushing control mechanism test .11
8.2.1 Mechanism activated by pressure drop .11
8.2.2 Mechanism activated by duration of operation .11
8.2.3 Mechanism activated by volume of filtered water .11
8.2.4 Mechanism activated by another physical quantity .12
8.3 Operation of the protective device .12
9 Information to be supplied by the manufacturer .12
9.1 General .12
9.2 Filter data .13
9.3 Back flushing controller .13
Annex A (informative) Types of irrigation media filters .14
Annex B (informative) Granulated media .15
Foreword
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URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems.
A list of all parts in the ISO 9912 series can be found on the ISO website.
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iv © ISO 2018 – All rights reserved

INTERNATIONAL STANDARD ISO 9912-4:2018(E)
Agricultural irrigation equipment — Filters for
microirrigation —
Part 4:
Granulated media filters
1 Scope
This document specifies construction requirements and test methods for pressurized granulated
media filters, hereinafter referred to as media filters, intended for operation in agricultural irrigation
systems.
It is applicable to both manual cleaning media filters and automatic self-cleaning media filters, used as
single unit or in batteries (two or more units working in parallel).
This document covers the operation and performance of a media filter, together with all related valves,
back flushing mechanism, underdrains, manifolds and other related accessories necessary for the
operation of the filter.
This document is applicable to three configurations of a filter.
a) An empty filter vessel (tank) housing.
b) A filter vessel filled with media filter material(s), complete with valves, connections, air release
and/or other accessories. This configuration, when connected to and controlled by a flushing
control device, is a complete operating single filter unit, usually positioned as a part of a filtration
station.
c) A filtration station, called “filter battery”.
Annex A provides information on types of irrigation media filters.
Annex B provides information on granulated media.
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 9644, Agricultural irrigation equipment — Pressure losses in irrigation valves — Test method
ISO 9912-1, Agricultural irrigation equipment — Filters for micro-irrigation — Part 1: Terms, definitions
and classification
ISO 9912-2:2013, Agricultural irrigation equipment — Filters for microirrigation — Part 2: Strainer-type
filters and disc filters
ISO 9912-3, Agricultural irrigation equipment — Filters for microirrigation — Part 3: Automatic flushing
strainer-type filters and disc filters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9912-1, ISO 9912-3 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
granulated media filter
media filter
permeable granulated media, such as sand, gravel, crushed granite or synthetic material, with a specific
gravity higher than water and used for filtration, provided the granules can be fluidized during back
flushing
3.2
clogged filter element
filter element that
...