1、January 2010DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 67.060!$Ts“1564980www.
2、din.deDDIN EN ISO 7971-3Cereals Determination of bulk density, called mass per hectolitre Part 3: Routine method (ISO 7971-3:2009)English version of DIN EN ISO 7971-3:2010-01Getreide Bestimmung der Schttdichte, sogenannte Masse je Hektoliter Teil 3: Routineverfahren (ISO 7971-3:2009)Englische Fassun
3、g DIN EN ISO 7971-3:2010-01www.beuth.deDocument comprises pages19DIN EN ISO 7971-3:2010-01 National foreword This standard has been prepared by Technical Committee CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR, France) in collaboration with Technical Committee ISO/TC 34 “Food products”
4、 (Secretariat: AFNOR, France), Subcommittee SC 4 “Cereals and pulses” (Secretariat: SAC, China) and has been published in accordance with the result of the parallel voting procedure within the scope of the Agreement on technical cooperation between ISO and CEN (Vienna Agreement) to adopt, without al
5、teration, International Standard ISO 7971-3:2009 as a European Standard. The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), Working Committee NA 057-05-06 AA Getreide und
6、Getreideerzeugnisse. DIN EN ISO 7971 consists of the following parts, under the general title Cereals Determination of bulk density, called mass per hectolitre: Part 1: Reference method Part 2: Method of traceability for measuring instruments through reference to the international standard instrumen
7、t Part 3: Routine method The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 7971-2 DIN EN ISO 7971-2 National Annex NA (informative) Bibliography DIN EN ISO 7971-2, Cereals Determination of bulk density, called mass per hectolitre Part 2:
8、Method of traceability for measuring instruments through reference to the international standard instrument 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7971-3 August 2009 ICS 67.060 English Version Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine m
9、ethod (ISO 7971-3:2009) Crales - Dtermination de la masse volumique, dite masse lhectolitre - Partie 3: Mthode pratique (ISO 7971-3:2009) Getreide - Bestimmung der Schttdichte, sogenannte Masse je Hektoliter - Teil 3: Routineverfahren This European Standard was approved by CEN on 8 August 2009. CEN
10、members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on appli
11、cation to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre h
12、as the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, P
13、ortugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any me
14、ans reserved worldwide for CEN national Members. Ref. No. EN ISO 7971-3:2009: E(ISO 7971-3:2009) Contents Page Foreword 3 1 Scope . 4 2 Normative references . 4 3 Terms and definitions. 4 4 Principle. 4 5 Apparatus 5 6 Procedure 5 6.1 General. 5 6.2 Hand-operated instruments. 5 6.3 Automatic instrum
15、ents. 6 6.4 Expression of results . 6 7 Precision 6 7.1 Interlaboratory test . 6 7.2 Repeatability 6 7.3 Reproducibility 6 7.4 Comparison of two groups of measurements in one laboratory. 7 7.5 Comparison of two groups of measurements in two laboratories 7 7.6 Uncertainty 7 8 Test report . 8 Annex A
16、(informative) Description of dimensions and use of KERN apparatus . 9 Annex B (informative) Description of dimensions and use of NILEMA LITRE apparatus 13 Annex C (informative) Results of interlaboratory tests 15 Bibliography . 17 EN ISO 7971-3:2009 (E) DIN EN ISO 7971-3:2010-01 2.Foreword This docu
17、ment (EN ISO 7971-3:2009) has been prepared by Technical Committee CEN/TC 338 “Cereal and cereal products”, the secretariat of which is held by AFNOR, in collaboration with Technical Committee ISO/TC 34 “Food products“. This European Standard shall be given the status of a national standard, either
18、by publication of an identical text or by endorsement, at the latest by February 2010, and conflicting national standards shall be withdrawn at the latest by February 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/o
19、r CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic,
20、 Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN ISO 7971-3:2009 (E) DIN EN ISO 7971-3:2010-01 31 Scop
21、e This part of ISO 7971 specifies a routine method for the determination of bulk density, called “mass per hectolitre” of cereals as grain using manual or automatic, mechanical, electric or electronic mass per hectolitre measuring instruments. NOTE Further details of the measuring instruments are sp
22、ecified in ISO 7971-2:2009, 6.4. 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) ap
23、plies. ISO 7971-2, Cereals Determination of bulk density, called mass per hectolitre Part 2: Method of traceability for measuring instruments through reference to the international standard instrument 3 Terms and definitions For the purposes of this document, the following terms and definitions appl
24、y. 3.1 bulk density “mass per hectolitre” cereals ratio of the mass of a cereal to the volume it occupies after being poured into a container under well-defined conditions NOTE 1 Bulk density is expressed in kilograms per hectolitre of grains as received. NOTE 2 The bulk density, as defined in this
25、part of ISO 7971, is different from “packing density” or “intrinsic density” of cereals. ISO 7971-1:2009 4 Principle The mass per hectolitre of a cereal is obtained from the mass of a volume of cereal determined under controlled sample filling and flow conditions. EN ISO 7971-3:2009 (E) DIN EN ISO 7
26、971-3:2010-01 4The mass per hectolitre can be affected by: a) space between the grains, which depends on the grain size and shape; b) density of the grains. 5 Apparatus 5.1 General requirement for bulk density apparatus. Any apparatus (5.2 and 5.3) shall be verified according to ISO 7971-2 and shall
27、 fulfil the performance demands specified therein. 5.2 Hand-operated measuring instrument. Apparatus consisting of a filling hopper, a measuring container and the accessories necessary for their use. The manner in which the grain is poured into the measuring container and the way in which it packs i
28、nto the container can cause the measurements taken by the various instruments to vary and lead to measurement errors. To minimize such variations, special attention should be given to ensuring that the design of the instruments and their size, material and shape are appropriate. NOTE Annexes A and B
29、 of this part of ISO 7971 contain examples of technical specifications of two hand-operated instruments with a capacity of 1 l. 5.3 Automatic measuring instrument. This category includes various types of devices, some of which can be used on their own or combined with an infrared analyser. The measu
30、rement is based on the application of equations to allow the correcting of the bias and/or the drifts monitored. It does not include manual weighing. The numeric value of the hectolitre mass is directly displayed. 5.4 Analytical balance, capable of being read to the nearest 0,1 g or 0,01 g depending
31、 on the volume of the container (see 6.2). 6 Procedure 6.1 General The measurements shall be taken using grain from which large impurities (straw, stones, husks, etc.) have been discarded, taking environmental conditions into consideration to ensure that there is no difference in temperature between
32、 the grain and the room in which the test is performed. Determine the bulk density in duplicate. For all the devices and for every sample, it is advisable to perform the two measurements on two different grain test portions. NOTE Repeating the measurement on the same grain test portion changes the f
33、riction coefficient which therefore makes it easier for the grains to slide; they are then more tightly packed, which increases the value of the bulk density. 6.2 Hand-operated instruments Check that the various components of the instrument are clean and that they are working properly. Make sure tha
34、t equipment is placed on a firm, flat base, after using a spirit level to check that the base is horizontal. Take great care to avoid any impact during filling. If the apparatus is jolted, cancel the test and start again. EN ISO 7971-3:2009 (E) DIN EN ISO 7971-3:2010-01 5Each type of apparatus is di
35、fferent; use each according to the manufacturers instructions. When using the analytical balance (5.4), weigh to the nearest 1 g for a 1 l container or the nearest 0,1 g for apparatus with a container of smaller volume. 6.3 Automatic instruments As the operations to be performed prior to the actual
36、measurement differ according to the type of equipment used, reference to the manufacturers instructions is recommended. Ensure that the instrument is placed on a horizontal surface in a room protected from extreme temperatures, humidity, dust and vibrations. Take particular care to: a) select the co
37、rrect cereal to be measured to ensure that the right calibration is used; b) use the volume of cereals recommended for the device in question; c) empty the collector drawer between samples. 6.4 Expression of results Take the arithmetic mean of the two determinations as the result if the repeatabilit
38、y conditions are met. Express the result to the nearest 0,1 kg/hl. 7 Precision 7.1 Interlaboratory test Details of an interlaboratory test on the precision of the method are summarized in Annex C. The values derived from this interlaboratory test cannot be applied to other bulk density ranges and ma
39、trices than those given. 7.2 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time, shall not in more that 5 % o
40、f cases be greater than the repeatability limit r = 0,4 for products whose mass per hectolitre is between 67,5 kg/hl and 84,5 kg/hl (see Tables C.1, C.2, and Figure C.1). 7.3 Reproducibility The absolute difference between two single test results, obtained using the same method on identical test mat
41、erial in different laboratories with different operators using different equipment, shall not in more that 5 % of cases be greater than the reproducibility limit R = 1,2 for products whose mass per hectolitre is between 67,5 kg/hl and 84,5 kg/hl (see Tables C.1, C.2, and Figure C.1). EN ISO 7971-3:2
42、009 (E) DIN EN ISO 7971-3:2010-01 67.4 Comparison of two groups of measurements in one laboratory Critical difference, CDr, is the difference between two averaged values obtained from two test results under repeatability conditions. As the result is a mean of two values (see 6.1), the comparison of
43、two bulk densities shall be made with critical difference. The critical difference, CDr, between two averaged values obtained from two test results under repeatability conditions is given by: 1211 1CD 2,8 2,8 1,98 0,2322 2rr r rsssnn=+= i.e. 0,2 kg/hl, after rounding, where sris the standard deviati
44、on of repeatability; n1and n2 are the number of test results corresponding to each averaged value (here, n1= n2= 2). 7.5 Comparison of two groups of measurements in two laboratories The critical difference, CDR, between two averaged values obtained in two different laboratories from two test results
45、 under repeatability conditions is given by: 22 2 2r1211CD 2,8 1 2,8 0,5 1,1822RR Rrss s snn=i.e. 1,2 kg/hl, after rounding, where sris the standard deviation of repeatability; sRis the standard deviation of reproducibility; n1and n2 are the number of test results corresponding to each of the averag
46、ed values (here n1= n2= 2). 7.6 Uncertainty Uncertainty, Ue, is a parameter representing the distribution of the values which may reasonably be attributed to the result. This uncertainty is given by a statistical distribution of the results from the interlaboratory test and is characterized by the e
47、xperimental standard deviation. For mass per hectolitre, the uncertainty is given by e2RUs= Ue= 0,43 2 = 0,86 i.e. 0,9 kg/hl, after rounding. EN ISO 7971-3:2009 (E) DIN EN ISO 7971-3:2010-01 78 Test report The test report shall contain at least the following information: a) an indication of the meth
48、od used, including a reference to this part of ISO 7971; b) the result obtained; c) all the operating details not specified in this part of ISO 7971 or those regarded as optional, in addition to any possible incidents that might have affected the result; d) all the information necessary for a full i
49、dentification of the sample. EN ISO 7971-3:2009 (E) DIN EN ISO 7971-3:2010-01 8Annex A (informative) Description of dimensions and use of KERN1)apparatus A.1 Dimensions of the apparatus A.1.1 General The dimensions of the various components of the apparatus should be as specified in A.1.2 to A.1.7. See Figure A.1 for a depiction of the components. A.1.2 Pre-filling measure Volume to level mark 1 350 ml 10 ml Internal diameter 86 mm 0,2 mm A.1.3 Filling hopper Internal diameter 79 mm 0,1 mm Wall thickness 1 mm 0
