Laboratory Glassware - Density Hydrometers for General Purposes - Part 1: Specification
|Publication Date:||15 August 1981|
|ICS Code (Measurement of volume, mass, density, viscosity):||17.060|
Scope and field of application
This part of ISO 649 specifies requirements for five basic series of glass hydrometers of constant mass which are graduated to indicate density (kg/m3 or g/ml) at 20 OC.
Each series comprises hydrometers which between them cover the interval 600 to 2 000 kg/ma3 or 0,6 to 2,0 g/ml. The hydrometers are graduated appropriately for use in liquids of low, medium or high surface tension.
It also specifies three sub-series of hydrometers which are graduated to indicate density at either 20 OC or 15 OC. These hydrometers have smaller tolerances on scale error, are limited to the range 600 to 1 100 kg/ma3 or 0,6 to 1,l g/ml and are for use in liquids of low surface tension.
This International Standard does not cover hydrometers with a built-in thermometer, for which a separate International Standard is under consideration. The hydrometers comply with the requirements of ISO 367.
A table of standard categories of surface tension is given in annex A. A table of recommended stem diameters is given, for guidance in manufacture, in annex B.
Part 2 of this International Standard deals with test methods and use of density hydrometers.