ISO-711-1985.pdf
《ISO-711-1985.pdf》由会员分享,可在线阅读,更多相关《ISO-711-1985.pdf(8页珍藏版)》请在三一文库上搜索。
1、International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEXCIYHAPOAHAR OPl-AHl43ALWlfl fl0 CTAH,QAPTM3ALWlM.ORGANISATION INTERNATIONALE DE NORMALISATION Cereals and cereal products - Determination of moisture content (Basic reference method) C b) easy to clean and having as little dead
2、 space as possible; c) enabling grinding to be carried out rapidly and uni- formly, without appreciable development of heat and, as far as possible, without contact with the outside air; d) adjustable so as to obtain particles of the dimensions indicated in 7.1.1. 5.4 Metal dish,3) non-corrodible un
3、der the test conditions, with a sufficiently tight-fitting lid and having an effective sur- face area such as to allow the test Portion to be distributed in a layer having a mass per unit area of not more than 0,3 g/cm? 5.5 Cup, made from glass or porcelain. 5.6 Drying tube? of glass, in two Parts,
4、one of which, in- tended to,receive the dish (5.41, is closed at one end, while the other, intended to receive the cup (5.5), carries a semi-capilla ry tube, with a stopcock, for evacuation purposes. The two Parts are connected by a ground glass joint. 1) This method has been applied successfully to
5、 the following products: wheat, rice (Paddy, husked and milled rice), barley, millet, rye and oats, in the form of grains, milled grains, semolina or flour. 2) i,3 to 2,6 kPa = 13 to 26 mbar = IO to 20 mmHg. 3) A suitable metal dish is shown, for information only, in figure 1. 4) A suitable drying t
6、ube is shown, for information only, in figure 2. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 21:38:59 MDTNo reproduction or networking permitted without license from IHS -,-,
7、- ISO 711-1985 (E) The test Portion may be cooled in this apparatus after drying, a desiccator (5.9) being then unnecessary for this Operation. 5.7 Constant-temperature oven, electrically heated, enabling the part of the drying tube (5.6) containing the dish (5.4) to be maintained at a temperature b
8、etween 45 and 50 OC. 5.8 Air-drying train : gas-washing bottle containing pure analytical gradesulfuric acid (g20 a 1,83 g/ml), connected to a tube containing pure analytical grade diphosphorus pentaoxide spread on glass wool. 5.9 Desiccator, containing an efficient desiccant. 6 Sampling See ISO 950
9、. 7 Procedure 7.1 Preparation of the test Sample 7.1.1 Products not requiring to be ground Products having particles of sizes less than or equal to 1,7 mm, less than 10 % (mlm) being over 1 mm and more than 50 % (mlm) being less than 0,5 mm, do not need to be ground before the determination. Mix the
10、 laboratory Sample thoroughly before taking the test Portion (7.2.1). 7.1.2 Products requiring to be ground If the Sample does not have the particle size characteristics mentioned in 7.1 .l, it shall be ground either without pre- conditioning (7.1.2.1) or with pre-conditioning (7.1.2.2). 7.1.2.1 Gri
11、nding without pre-conditioning For products which are not likely to undergo variations in moisture content in the course of grinding in general, products with a moisture content between 7 and 17 % (mlm)t) (sec 9.111, carry out grinding without pre-conditioning. Adjust the grinding mill (5.3) to obta
12、in particles of the dimen- sions indicated in 7.1.1, grind a small quantity of the laboratory Sample and discard it. Then quickly grind about 3,5 g of the laboratory Sample, and immediately proceed in accordance with 7.2.2. 7.1.2.2 Grinding with pre-conditioning Products which are likely to undergo
13、changes in moisture con- tent in the course of grinding in general, products with a moisture content more than 17 % (mlm)t) or less than 7 % (mlm) shall be pre-conditioned so as to bring their moisture content to between 7 and 17 % (mlm)t) if possible between 9 and 15 % (mlm) (sec 9.113, before grin
14、ding. If the moisture content is more than 17 % (m/mV) (the more frequent case), weigh, to the nearest 0,2 mg, about 3,5 g of the laboratory Sample and pre-dry it in accordance with 7.3, except that the drying time shall be 1,5 to 2 h (sec 9.2) and it is unnecessary to renew the diphosphorus pentaox
15、ide. If the moisture content is less than 7 % (mlm), place about 3,5 g of the laboratory Sample, weighed to the nearest 0,2 mg, in a suitable atmosphere (usually that of the laboratory) and leave it to acquire a moisture content within the limits specified above. After conditioning, weigh the Sample
16、 to the nearest 0,2 mg, grind it immediately in the grinding mill (5.31, adjusted to obtain particles of the dimensions indicated in 7.1.1, and immediately proceed in accordance with 7.2.2. 7.2 Test Portion 7.2.1 For products not requiring to be ground, rapidly weigh, to the nearest 0,2 mg, about 3
17、g of the test Sample (7.1 .l) into the dish (5.41, previously dried and weighed, together with its lid, to the nearest 0,2 mg. 7.2.2 In the case of products which have had to be ground, rapidly weigh all the grindings obtained (7.1.2.1 or 7.1.2.2) into the dish (5.41, previously dried and weighed, t
18、ogether with its lid, to the nearest 0,2 mg. 7.3 Drying Place the open dish (leaving its lid in the desiccator) containing the test Portion (7.2) at the closed end of the drying tube (5.6); introduce, near to it, the cup (5.5) containing a layer of diphosphorus pentaoxide about 1 cm thick. Fit the t
19、wo Parts of the drying tube together and reduce the pressure in the assembled tube to a value of the Order of 1,3 to 2,6 kPa, using the vacuum apparatus (5.2); this should be done gradually in Order to avoid material being thrown out of the dish. Close the connection to the vacuum apparatus, and pla
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ISO 711 1985
链接地址:https://www.31doc.com/p-3782304.html