ISO 11520-2:2001
(Main)Agricultural grain driers — Determination of drying performance — Part 2: Additional procedures and crop-specific requirements
Agricultural grain driers — Determination of drying performance — Part 2: Additional procedures and crop-specific requirements
This part of ISO 11520 specifies additional procedures and gives guidance for testing and evaluating the drying performance of continuous-flow and batch grain driers for specific grain crops including wheat, barley, oats, maize, rice, sorghum and rape. It supplements the general procedures given in ISO 11520-1 based on drying only wheat over the limited range of moisture content of 20 % to 15 % wet basis. Methods and data are given for a) determining the evaporation rate of driers when drying grain crops under steady state conditions, and b) correcting the main drier performance characteristics, including evaporation rate, grain flow rate, drying time and specific energy and fuel consumption, to reference and other ambient conditions. Procedures are specified for sampling input and output grain to assess changes in grain quality.
Séchoirs à grains agricoles — Détermination des performances de séchage — Partie 2: Modes opératoires supplémentaires et exigences spécifiques à la récolte
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 11520-2
First edition
2001-02-01
Agricultural grain driers — Determination of
drying performance —
Part 2:
Additional procedures and crop-specific
requirements
Séchoirs à grains agricoles — Détermination des performances de
séchage —
Partie 2: Modes opératoires supplémentaires et exigences spécifiques à la
récolte
Reference number
©
ISO 2001
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ii © ISO 2001 – All rights reserved
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative reference .1
3 Terms and definitions .1
4 Symbols and abbreviated terms .4
5 Test procedure.5
5.1 General.5
5.2 Test period.5
5.3 Frequency of sampling grain.5
5.4 Moisture removal .6
5.5 Grain dampening .7
5.6 Procedure for a multi-pass test.7
6 Grain quality.8
6.1 General.8
6.2 Input grain .8
6.3 Output grain .9
7 Methods of correction of test results .10
7.1 General.10
7.2 Evaporation rate.10
7.3 Mass flow rate of grain.13
7.4 Corrected drying time .13
7.5 Specific thermal energy, total energy and fuel consumption .13
8 Test report .14
Annex A (informative) Grain moisture content and sampling .15
Annex B (informative) Moisture removal in specific crops.19
Annex C (normative) Testing reduction in grain germination.20
Annex D (normative) Tables for correction of drier performance.21
Annex E (informative) Airflow calculations .99
Bibliography.102
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 3.
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 part of ISO 11520 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 11520-2 was prepared by Technical Committee ISO/TC 23, Tractors and machinery for
agriculture and forestry, Subcommittee SC 7, Equipment for harvesting and conservation.
ISO 11520 consists of the following parts, under the general title Agricultural grain driers — Determination of drying
performance:
� Part 1: General
� Part 2: Additional procedures and crop-specific requirements
Annexes C and D form a normative part of this part of ISO 11520. Annexes A, B and E are for information only.
iv © ISO 2001 – All rights reserved
Introduction
ISO 11520-1 covers only those methods for evaluating the drying performance of continuous-flow and batch grain
driers to be used when drying rewetted wheat with a moisture content in the range 20 % to 15 % wet basis.
The methods specified in this part of ISO 11520 take account of the following factors:
� a greater range in input and output moisture contents;
� other crops apart from wheat;
� the impracticality of rewetting (dampening) some grains and of differing thermal characteristics.
For correcting the observed evaporation rates to those to be expected at different reference ambient and specified
grain conditions, the correction formulae given in ISO 11520-1 are augmented by a series of tables from which
correction factors are found by interpolation.
The methods specified are for determining the water evaporation rate which the machines concerned are able to
achieve when drying wheat and other grains under the steady-state conditions prevailing during the tests. Methods
for correcting observed performance to other input and reference ambient conditions are also specified.
INTERNATIONAL STANDARD ISO 11520-2:2001(E)
Agricultural grain driers — Determination of drying performance —
Part 2:
Additional procedures and crop-specific requirements
1 Scope
This part of ISO 11520 specifies additional procedures and gives guidance for testing and evaluating the drying
performance of continuous-flow and batch grain driers for specific grain crops including wheat, barley, oats, maize,
rice, sorghum and rape. It supplements the general procedures given in ISO 11520-1 based on drying only wheat
over the limited range of moisture content of 20 % to 15 % wet basis.
Methods and data are given for
a) determining the evaporation rate of driers when drying grain crops under steady state conditions, and
b) correcting the main drier performance characteristics, including evaporation rate, grain flow rate, drying time
and specific energy and fuel consumption, to reference and other ambient conditions.
Procedures are specified for sampling input and output grain to assess changes in grain quality.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this part of ISO 11520. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 11520 are encouraged to investigate the
possibility of applying the most recent edition of the normative document indicated below. For undated references,
the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of
currently valid International Standards.
ISO 11520-1:1997, Agricultural grain driers — Determination of drying performance — Part 1: General.
3 Terms and definitions
For the purposes of this part of ISO 11520, the terms and definitions given in ISO 11520-1 and the following apply.
3.1
reference ambient conditions
ambient conditions of temperature, relative humidity and barometric pressure to which the results of a drier test are
to be corrected
3.2
airflow rate
volume of air flowing in unit time per unit volume of grain (this value is also the number of air changes per unit of
time)
NOTE There are several ways of expressing airflow rate, but for comparison between driers and crops it is convenient to
express it in this way.
3.3
drying period
period during which drying air passes through grain
3.4
cooling period
period during which ambient or near-ambient air passes through grain
3.5
tempering
process by which partially dried grain is held in temporary storage for a number of hours without ventilation,
allowing equalization of moisture content within the grain kernel with minimal stress cracking
NOTE When drying rice, a common practice is to cool it to within 2 °C of ambient prior to tempering for a minimum of 4 h.
One or more further drying, cooling and tempering cycles may be given.
3.6
dryeration
process by which hot grain is taken directly from a drier and allowed to temper for a minimum of 4 h before being
cooled slowly so as to extract additional moisture without using additional fossil fuel
NOTE The hot grain referred to is usually maize or rice, sorghum, soybeans or wheat.
3.7
test period
period during which a continuous-flow drier operating at a single steady state for at least one residence time, or a
batch drier completing a single full cycle of drying and cooling, is monitored to enable its thermodynamic
performance to be assessed
NOTE In multi-pass drying there may be several test periods.
3.8
wheat
grain of the genus Triticum, of which the commercially important species are T. aestivum (breadwheat), T. durum
and T. compactum (club wheat)
3.9
barley
grain of Hordeum sativum or H. vulgare
3.10
oats
grain of Avena sativa L.
3.11
naked oats
grain of Avena nuda L., which readily loses the husk at threshing
NOTE Naked oats have a high protein and oil content and the loss of husk makes the kernels prone to rancidity.
3.12
maize
grain of Zea mays L.
NOTE This is commonly referred to as corn in North America and some other countries. There are about seven different
types of maize distinguished at the “convar” level of classification (between species and cultivar) and within each type there are
hybrids having different drying properties. The most widely grown type is the convar indentata commonly known as “dent corn”.
2 © ISO 2001 – All rights reserved
3.13
rice
grain of OryzasativaL.
3.14
paddy rice
rough rice
rice with the hull or husk still intact
3.15
brown rice
rice kernel from which the hull or husk has been removed during the milling process
3.16
milled rice
white rice
white grain or kernel remaining after the removal of the husk or hull and of the bran (whitening); the embryo or
germ may be totally or partly removed and part of the bran may still remain on the grain
NOTE For some end uses, rice may be dried in the milled condition.
3.17
head rice
for brown and mi
...
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