BS EN 62021-3:2014
$142.49
Insulating liquids. Determination of acidity – Test methods for non mineral insulating oils
| Published By | Publication Date | Number of Pages |
| BSI | 2014 | 28 |
This part of IEC 62021 describes two procedures for the determination of the acidity of unused and used electrical non-mineral insulating oils. Method A is potentiometric titration and Method B is colourimetric titration.
In unused and used non-mineral insulating oils, the constituents that may be considered to have acidic characteristics include organic acids, phenolic compounds, some oxidation products, resins, organometallic salts and additives.
The method may be used to indicate relative changes that occur in non-mineral insulating oil during use under oxidizing conditions regardless of the colour or other properties of the resulting non-mineral oil.
The acidity can be used in the quality control of unused non-mineral insulating oil.
As a variety of oxidation products present in used non-mineral insulating oil contribute to acidity and these products vary widely in their corrosion properties, the test cannot be used to predict corrosiveness of non-mineral insulating oil under service conditions.
The acidity results obtained by potentiometric test method may or may not be numerically the same as those obtained by colourimetric methods, but they are generally of the same magnitude.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 8 | INTRODUCTION |
| 9 | 1 Scope 2 Normative references 3 Terms and definitions |
| 10 | 4 Method A: Automatic potentiometric titration 4.1 Principle 4.2 Reagents and auxiliary products 4.2.1 Reagents 4.2.2 Titration reagent 4.2.3 Titration solvent |
| 11 | 4.2.4 Potassium hydrogen phthalate, primary standard 4.2.5 Reference electrode electrolyte 4.2.6 Aqueous buffer solutions 4.2.7 Glass electrode cleaning solution 4.3 Apparatus 4.3.1 Potentiometric titration apparatus 4.3.2 Glass indicator electrode |
| 12 | 4.3.3 Reference electrode 4.3.4 Stirrer 4.3.5 Titration vessel 4.3.6 Titration stand 4.4 Sampling 4.5 Preparation and maintenance of electrode system 4.5.1 Preparation 4.5.2 Maintenance |
| 13 | 4.6 Calibration 4.6.1 Calibration of pH titrimeter 4.6.2 Settings for the potentiometric instrument |
| 14 | 4.7 Procedure 4.7.1 General 4.7.2 Standardization of alcoholic potassium hydroxide solution Figures Figure 1 – Potentiometric titration curve |
| 15 | 4.7.3 Blank titration 4.7.4 Sample titration |
| 16 | 4.8 Calculation of result 4.9 Precision 4.9.1 Repeatability 4.9.2 Reproducibility |
| 17 | 4.10 Report 5 Method B: Colourimetric titration 5.1 Principle 5.2 Reagents 5.2.1 General 5.2.2 Titration reagent |
| 18 | 5.2.3 Titration solvent 5.2.4 Potassium hydrogen phthalate, primary standard 5.2.5 Standard hydrochloric acid solution 5.2.6 Alkali blue 6B indicator solution 5.2.7 Cobalt nitrate solution 5.3 Apparatus 5.3.1 Titration vessel 5.3.2 Stirrer 5.3.3 Burette 5.4 Sampling |
| 19 | 5.5 Procedure 5.5.1 General 5.5.2 Standardization of alcoholic potassium hydroxide solution 5.5.3 Blank titration |
| 20 | 5.5.4 Sample titration 5.6 Calculation of result 5.7 Precision 5.7.1 Repeatability |
| 21 | 5.7.2 Reproducibility 5.8 Report |
| 22 | Annex A (informative) Determination of acidity in non-mineral electrical insulating oils by photometric titration A.1 Principle A.2 Reagents and solvents A.3 Preparation of titration solutions and solvents A.3.1 Potassium hydroxide alcoholic solution (0,01 mol/l) A.3.2 Potassium hydrogen phthalate solution (0,01 mol/l) |
| 23 | A.3.3 Titration solvent A.4 Apparatus A.4.1 Volumetric titrator A.4.2 Titration vessel A.4.3 Titration stand A.4.4 Stirrer A.4.5 Recorder/printer A.4.6 Photometric sensor |
| 24 | A.5 Sampling A.6 Procedure A.6.1 Preparation and maintenance of the titration system A.6.2 Determination of acidity of the titration solvent (blank titration) A.6.3 Determination of molarity of the potassium hydroxide alcoholic solution(0,01 mol/l) |
| 25 | A.6.4 Titration of soluble acidity in the oil sample A.7 Calculation of result A.8 Report |
| 26 | Figure A.1 – Molecular structure of para-naphtholbenzein indicator in a) acidic media and b) basic media Figure A.2 – UV spectra of para-naphtholbenzein indicator in toluene/2-propanol/water solution in acidic media (curve a) and basic media (curve b) |
