Method for reclassifying PCB transformers
US4950837A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1989 |
| Grant date | Aug 21, 1990 |
| Priority date | — |
| Expiry date | Jul 18, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/909
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention is directed to a method for reducing PCB concentration in an electrical induction apparatus containing a dielectric fluid with greater than 500 ppm PCB to a level of less than about 50 ppm PCB. Dielectric fluid containing greater than 500 ppm PCB is drained from an electrical induction apparatus, and the drained apparatus then is filled with tetrachloroethylene as a first interim dielectric fluid. The apparatus is then electrically operated with the first interim dielectric fluid so as to attain about an equilibrium PCB concentration in the first fluid. The first interim dielectric fluid then is drained from the apparatus and replaced with fresh tetrachloroethylene as a second interim dielectric fluid. The apparatus then is electrically operated with the second interim dielectric fluid so as to attain about an equilibrium PCB concentration in the second fluid. The second interim dielectric fluid then is drained from the apparatus and replaced with a silicone fluid as a permanent dielectric fluid. The apparatus filled with permanent dielectric fluid is electrically operated and the permanent dielectric fluid is filtered through a carbon filter, so as to attain …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.