ISO-649-1-1981.pdf

International Standard 649/I lNTERNATlONALORGANlZATlON FOR STANDARDIZATIDNMEMW HAPOAHAR OPI AH#BAl b) there shall be a medium line between two consecutive long lines; c) there shall be four short lines between consecutive medium and long lines. 10.3.2 On hydrometer scales whose smallest interval is 2 kg/m3 or 0,2 kg/m3 or 0,002 g/ml or O,OfXl2 g/ml :. a) every fifth graduation line shall be a long line; b) there shall be four short lines between two consecutive long lines. 10.3.3 On hydrometer scales whose smallest interval is 5 kg/ma or 0,005 g/ml : a) every tenth graduation line shall be a long line; b) there shall be four medium lines between two con- secutive long lines; c) there shall be one short line between two consecutive medium lines and between consecutive medium and long lines. 10.4 Figuring of graduation lines 10.4.1 Except in the case of duplicate scales, the scale shall have only one set of numbers, and the lastdigitsof thenumbers shall be vertically aligned. 10.4.2 The scale shall be figured so as to enable the value cor- responding to any graduation line to be readily indentified. 10.4.3 The highest and lowest graduation lines of the nominal limits shall be figured in full. 10.4.4 At least every tenth line shall be figured. IO.45 For density values expressed in grams per millilitre, the decimal sign shall be included for numbers expressed in full, but may be omitted from abbreviated numbers. 10.5 Extension of scale The scale shall be extended beyond the nominal scale limits as indicated in table 1. 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:56:20 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO949/1=1991(E) 13ooE - = - 1300: 0,8=00 EE) 0,8 - - - 052 - 022= 7 -05 =02 ilLI= - - = 06-z - - ostx - - - - 1oz = - lo= =10 - - - L 153 - - 715 E =08 - - 202 El0 - 25 = -25 730 -35 -40 =45 0,8-50 12- - - - - - - 3-z - - - - - - 353 - - - - - - b) the reference temperature of the hydrometer, for example “20 OC”; c) 1) either a particular surface tension expressed in millinewtons per metre (for example “55 mN/m”); 2) or a surface tension category as defined in annex A (for example “low S.T.“); 3) or, if the instrument is adjusted for use in a particular liquid, the name of that liquid; d) whether the hydrometer is adjusted for readings at the top of the meniscus (Le. for use in opaque liquids); e) the maker s and/or vendor s name or readily identifiable mark; f) identification number of the instrument, the first two digits of which may indicate the year of manufacture (for example “7KKKI1”); g) the number of this International Standard (i.e, IS0 64911) or the number of the corresponding national standard; h) the series number (for example “L50”). Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:56:20 MDTNo reproduction or networking permitted without license from IHS -,-,- Is0649/14981E) Annex A Standard categories of surface tension for hydrometers (This annex forms part of the Standard.1 The standard categories of surface tension given in table 3 are adopted for hydrometers for technical use, so as to provide a precise basis for adjustment and verification and to permit the attainment of the appropriate accuracy in measurements in the liquids indicated The adoption of these surface tension categories does not preclude the use of other surface tensions as the basis for the adjustment of hydrometers, provided such surface tensions are marked, in millinewtons per metre, within the hydrometers or reference is made to the type of the liquid. Attention is drawn to the requirements of clause 14 c), Table 3 shows the surface tensions for the adjustment of hydrometers related to the minima of their density range. If surfaces of aqueous solutions (except those of acetic acid and of nitric acid of density greater than 1300 kg/m3 or I,3 g/ml) are specially cleaned, for example by overflow, then the surface tension is increased to approximately 75 mN/m, Table 3 - Standard categories of surface tension Density g/ml 0,oo 0,02 0.04 0,06 o,oa Category Example of liquids to which kg/n+ g/ml kg/r+ 0 20 40 66 60 the category is appropriate Surface tension mN/m Low 6m 0,6 15 16 17 18 19 Organic liquids generally (including ethers, 700 087 20 21 22 23 24 petroleum distillates, coaltar, distillatesl, and 806 0,8 25 26 27 28 29 all types of oils. Aqueous solutions of low 900 03 30 31 32 33 34 molecular mass organic substances. 1 000 to 1 300 1.00 to I,30 35 Acetic acid solutions, the free sufaces of inclusive inclusive which have not been specially cleaned, and heavy oils. Medium 6ooto840 0,60 to 0,94 as for the “low” category above Aqueous solutions of low molecular mass inclusive inclusive organic substances (including those of 960 0,96 35 ethanol and methanol, but excluding acetic 970 0,97 40 acid solutions), the free surfaces of which 88u 038 45 have not been specially cleaned. 990 09 50 1 OOOto2006 l,oo to 2,cKl 55 Nitric acid solutions of densities greater than inclusive inclusive 1 300 kg/m3 or I,3 g/ml, whether the free surfaces have been specially cleaned or not. High 1030t02600 1 ,oo to 2,rXr 75 Aqueous solutions, the surfaces of which inclusive inclusive have been specially cleaned, except : a) nitric acid of density greater than 1 300 kg/m3 or I,3 g/ml: b) acetic acid solutionslr. 1) Acetic acid solutions show extreme variability of surface tension. 8 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:56:20 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO649/1-1981(E) Annex B Recommended stem diameters for hydrometers The diameters shown in table 4 are not mandatory. They are intended for guidance in manufacture. Table 4 - Recommended stem diameters Upper limit of nominal range kg/m3 g/ml 600 0,6 700 0,7 800 On8 900 03 1000 to 1 loo 1,l 1200 12 1300 1,3 1400 64 1500 1,5 1600 1,6 1700 1,7 1800 1,8 Series KO, L50, L5oSP Series M50, MlW and MWSP SW and SSOSP mm mm mm 66 7,l 64 61 683 53 5,7 62 5,5 5,4 5,9 5,2 5,l 5,5 49 49 5,3 4,7 4,7 5,o 4,5 4,5 489 4,3 4,3 4,7 4,2 4,2 4,5 4,O” 4,O” 4,4 4,O” 4,O 4,2 4,0* 4,Of 4,l 4,0* 1 900 1 1,9 1 4,0* 1 4,0* 1 4,0* * 4.0 mm is the minimum stem diameter permitted in 12.4. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Defense Supply Ctr/9960866100 Not for Resale, 04/24/2007 10:56:20 MDTNo reproduction or networking permitted without license from IHS -,-,-