1、BS EN ISO7971-1:2009ICS 67.060NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDCereals Determination of bulkdensity, called massper hectolitrePart 1: Reference method (ISO7971-1:2009)This British Standardwas published underthe authority of theStandards Policy and
2、Strategy Committee on 30November 2009. BSI 2009ISBN 978 0 580 58445 9Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 7971-1:2009National forewordThis British Standard is the UK implementation of EN ISO 7971-1:2009.It supersedes BS ISO 7971-1:2003 which is withdrawn.The UK partic
3、ipation in its preparation was entrusted to TechnicalCommittee AW/4, Cereals and pulses.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for i
4、ts correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7971-1 August 2009 ICS 67.060 English Version Cereals - Determination of bulk density, called mass per hectolitre - Part 1: Reference method
5、 (ISO 7971-1:2009) Crales - Dtermination de la masse volumique, dite masse lhectolitre - Partie 1: Mthode de rfrence (ISO 7971-1:2009) Getreide - Bestimmung der Schttdichte, sogenannte Masse je Hektoliter - Teil 1: Referenzverfahren (ISO 7971-1:2009) This European Standard was approved by CEN on 8 A
6、ugust 2009. CEN 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 o
7、btained on application 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 Man
8、agement Centre has 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, N
9、orway, Poland, Portugal, 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 fo
10、rm and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7971-1:2009: EBS EN ISO 7971-1:2009EN ISO 7971-1:2009 (E) 3 Foreword This document (EN ISO 7971-1:2009) has been prepared by Technical Committee CEN/TC 338 “Cereal and cereal products”, the secretariat of which is held
11、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 by publication of an identical text or by endorsement, at the latest by February 2010, and conflicting national standards shall be withdrawn
12、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/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the
13、 national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Nor
14、way, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN ISO 7971-1:2009ISO 7971-1:2009(E) ISO 2009 All rights reserved iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
15、 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, gover
16、nmental 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 D
17、irectives, 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
18、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 7971 (all parts) was prepared by the European Committee for Standardizatio
19、n (CEN) Technical Committee CEN/TC 338, Cereal and cereal products, in collaboration with Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals and pulses, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement). This second edition cancels
20、 and replaces the first edition (ISO 7971-1:2003), which has been revised to take account of ISO 7971-2:2009. 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 f
21、or measuring instruments through reference to the international standard instrument Part 3: Routine method BS EN ISO 7971-1:2009BS EN ISO 7971-1:2009INTERNATIONAL STANDARD ISO 7971-1:2009(E) ISO 2009 All rights reserved 1Cereals Determination of bulk density, called mass per hectolitre Part 1: Refer
22、ence method 1 Scope This part of ISO 7971 specifies the reference method for the determination of bulk density, called “mass per hectolitre”, of cereals as grain. NOTE Several routine methods are used in different countries. A routine method for the determination of bulk density, called “mass per he
23、ctolitre”, is given in ISO 7971-3. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 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 condi
24、tions NOTE 1 Bulk density is expressed in kilograms per hectolitre of grain as received. NOTE 2 The bulk density, as defined in this part of ISO 7971, is different from “packing density” or “intrinsic density” of cereals. 3 Principle A sample is poured in a controlled manner from a hopper into a 20
25、l container, which is then weighed. 4 Requirements for apparatus 4.1 General The apparatus used shall comply with the following requirements, which correspond to those in OIML R 15 2, and shall be similar to that shown in Figure 1. BS EN ISO 7971-1:2009ISO 7971-1:2009(E) 2 ISO 2009 All rights reserv
26、edDimensions in millimetres Figure 1 Apparatus for determining bulk density of cereals (continued) BS EN ISO 7971-1:2009ISO 7971-1:2009(E) ISO 2009 All rights reserved 3Key 1 filling hopper 11 shutter 2 truncated cone for guiding the flow of grain 12 frame of straightedge 3 straightedge counterweigh
27、t 13 straightedge 4 guiding skirt for surplus grain 14 straightedge counterweight 5 guide by rail and rollers of the frame of the straightedge 15 height of flow 6 removable part of skirt allowing the measuring container to be removed 16 wedged base support of measuring container in filling position
28、7 measuring container, volume 20 l 17 collecting box for surplus grain 8 base support of measuring container 18 distributor 9 tapered emptying tube 19 straightedge 10 guiding collar for grain flow 20 handle of wedge for base support NOTE This figure is for information only except for the dimensions
29、shown, which are obligatory. Figure 1 Apparatus for determining bulk density of cereals 4.2 Description and operation 4.2.1 Pre-filling container. The pre-filling measure has a nominal volume of 24 l. Its internal form is a right circular cylinder with height approximately equal to its diameter. 4.2
30、.2 Filling hopper. The hopper has the shape of a truncated vertical circular cone surmounted by a cylindrical rim. Its lower part terminates in an axial tube with a slightly tapering bore, the wider end of which is at the bottom. A shutter, hinge-mounted on the tube and able to close the tube comple
31、tely, controls the emptying process. The hopper receives from the pre-filling container a quantity of grain greater than the content of the measuring container. 4.2.3 Distributor. The distributor is an inverted circular mushroom-shaped element connected to the bottom end of a vertical rod positioned
32、 in the axis of the hopper. The rod lowers the distributor inside the tapered tube to an adjustable level from top to bottom to allow adjustment of the apparatus: lowering the distributor increases the rate of flow of the grain, which collects in greater quantity owing to compaction in the measuring
33、 container, thus giving higher results; conversely, the results are lower when the distributor is raised. 4.2.4 Measuring container. The measuring container has a nominal volume of 20 l. Its internal form is a right circular cylinder with height approximately equal to its diameter. Its upper edge is
34、 ground flat. 4.2.5 Base support for the measuring container. A base on rails supports the container and allows it to travel underneath the hopper, in the axis of which it can be locked, or taken out of the chassis for easy removal. 4.2.6 Protection and guiding collar for grain flow. A cylindrical c
35、ollar, of the same diameter as the measuring container, is placed between the hopper and the measuring container, leaving a horizontal space between its lower edge and the upper edge of the container to allow the passage of a straightedge. During filling, the collar, which is surmounted by a truncat
36、ed cone-shaped section, protects the grain as it drops and at the end retains the surplus grain. 4.2.7 Straightedge (levelling blade). The straightedge is a flat, thin but rigid steel blade, sharpened to the form of an open V at the front. It is fixed horizontally in a frame mounted on rollers and d
37、riven in its plane by a counterweight. BS EN ISO 7971-1:2009ISO 7971-1:2009(E) 4 ISO 2009 All rights reservedThe frame guides the straightedge across the grain in the gap between the collar and the upper edge of the measuring container. The movement shall be continuous and not jerky, and the straigh
38、tedge shall touch neither the collar nor the container. In its movement, the straightedge levels the grain to the level of the measuring container, thus giving a determined volume. 4.2.8 Collecting box for surplus grain. At the same time as levelling the grain, the straightedge also closes off the l
39、ower surface of the collar as it removes from the container any grain surplus to its volume. When the straightedge is drawn back, with the container removed, this surplus grain falls into a collecting box placed beneath the base of the container and towards which the grain is guided by a skirt. 4.2.
40、9 Overall assembly. The apparatus is assembled in a rigid chassis equipped with a verticality adjustment screw; verticality is checked by means of a plumbline or a spirit-level. The hopper with its tube and distributor, the collar and the measuring container shall be coaxial and positioned verticall
41、y by means of the adjustment device described above, the upper edge of the measuring container thus being horizontal. 4.2.10 Weighing device. The grain contained in the measuring container is weighed using a non-automatic balance which has been weighted to compensate for the mass of the empty contai
42、ner. Therefore, one single weighing gives the mass of the grain. The error of the balance shall not exceed 0,01 % of load between 10 kgf and 20 kgf or, when using weights, the sum of errors of weights shall not exceed 0,02 %. 4.3 Dimensions 4.3.1 Pre-filling container This shall have the following d
43、imensions: volume to top: 24 l 0,1 l; internal diameter: 300 mm 10 mm; internal height: approximately 340 mm, adjusted to obtain the specified volume. 4.3.2 Filling hopper This shall have the following dimensions: a) top rim internal diameter: 390 mm 1 mm; height: 120 mm 2 mm; b) truncated-cone body
44、 upper internal diameter: 390 mm 1 mm; lower internal diameter: 84,5 mm 0,5 mm; height: 240 mm 1 mm; BS EN ISO 7971-1:2009ISO 7971-1:2009(E) ISO 2009 All rights reserved 5c) emptying tube top internal diameter: 84,5 mm 0,5 mm; bottom internal diameter: 86,5 mm 0,5 mm; length: 80 mm 0,5 mm. 4.3.3 Dis
45、tributor This shall have the following dimensions: a) diameter of the rod: 11 mm 0,2 mm; b) mushroom-shaped element diameter: 33 mm 0,2 mm; head thickness: 5 mm 0,5 mm; connecting radius to the rod: 16 mm 0,5 mm; c) distance from bottom surface of mushroom to bottom end of emptying tube: 14 mm 0,5 m
46、m. 4.3.4 Measuring container This shall have the following dimensions: volume up to ground top: 20 l 0,01 l; internal diameter 295 mm 1 mm; internal height: approximately 292 mm, adjusted to obtain the specified volume. 4.3.5 Base support for measuring container This shall have the following dimensi
47、ons: distance between bottom of inside of container and bottom end of emptying tube: 500 mm 2 mm; distance between top of container and lower surface of straightedge: 0,5 mm 0,2 mm. 4.3.6 Protection and guiding collar for grain flow This shall have the following dimensions: internal diameter: 295 mm
48、 1 mm; height: 78 mm 2 mm; distance between lower edge of collar and upper surface of straightedge: 0,5 mm 0,2 mm. 4.3.7 Straightedge (levelling blade) This shall have the following dimensions: thickness of blade: 3 mm 0,2 mm; mass of driving counterweight: 5 kg 0,1 kg. BS EN ISO 7971-1:2009ISO 7971
49、-1:2009(E) 6 ISO 2009 All rights reserved4.3.8 Chassis A plumbline shall be provided of length at least 500 mm (or spirit-level of the same sensitivity), for checking verticality. 4.4 Calibration and adjustment 4.4.1 Calibration Calibration of the apparatus (l) is carried out by comparison with a calibrated national or international measurement standard instrument1)(E). Use a wheat free from impurities, whose grains are approxi
