BS 5470:1977 pdf free.Specification for glass alcohol hydrometers not incorporating a thermometer.
1 Scope and field of application
BS 5470 specifies the requirements of instruments suitable for the accurate determination of the ethanol content of simple mixtures of ethanol and water. They are graduated in density (kg/m3). One class of accuracy is specified.
2 References The titles of the publications referred to in this standard are listed on page 6.
3 Basis of scales 3.1 The standard reference temperature for the instruments shall be 20 °C. 3.2 The instruments shall be graduated for reading at the level of the free horizontal surface of the liquid.
4 Description
4.1 Each instrument shall consist of a cylindrical body whose lower end is of such a form, cone-shaped or hemispherical, as will effectively prevent the entrapment of air hubbies.
4.2 At its upper end the body shall be fused on to a hollow cylindrical stem. The top end of the stem shall be sealed.
4.3 The shape of the instrument shall be symmetrical about its longitudinal (vertical) axis. Its cross section shall not exhibit any abrupt variations.
4.4 The loading material for adjusting the mass of the instrument shall be contained in the lower part of the body.
4.5 The stem shall contain a graduated scale, marked on a cylindrical strip of suitable material (see 6.2. 6.3 and 6.4) which shall be securely fastened to the interior of the stem. Datum marks shall be provided on the strip and on the stem in order that any displacement of the former relative to the latter would be readily apparent.
6 Scale
61 The instrument shall not have more than one scale.
6.2 The scale and the inscriptions shall be marked on a strip having a smooth matt surface of white or off-white colour. The graduations within the nominal scale limits and the inscriptions shall he marked in black. Graduations outside the nominal scale limits (see 6.9) may be marked in a colour other than black.
6.3 The strip bearing the scale shall be of cylindrical form, straight and free from twist.
6.4 The strip bearing the scale shall show no evidence of charring. The strip shall not become discoloured or distorted when the stem is maintained for 24 h at a temperature of 70 °C.
6.5 The graduation lines shall lie in planes perpendicular to the axis of the stem. They shall be distinct and of uniform thickness not exceeding one-fifth of the distance between the centres of adjacent graduation lines or 0.2 mm, whichever is less.BS 5470 pdf download.