| 摘要 |
1529066 Electrical insulating oil NIPPON OIL CO Ltd 2 Dec 1975 [2 Dec 1974 26 Sept 1975] 49501/75 Heading C5E An electrical insulating oil comprises a blend of two specified mineral oils, A and B, optionally with a third oil C. Oil A has a sulphur content not more than 0À5%, a pour point of - 10‹ to -25‹ C. and a nitrogen content not more than 100ppm, and is made by hydrofining and dewaxing a fraction boiling wholly or mainly between 280‹ and 400‹ C. and obtained from a paraffinic or intermediate crude oil (US Bureau of Mines classification). Oil B is obtained by hydrofining a fraction boiling wholly or mainly between 250‹ and 400‹ C. obtained as a by-product in the reforming of hydrocarbons over a noble-metal catalyst. The proportions are 5-100 parts of B to 100 parts of A, and the hydrofining may be before or after blending. Oil C, when used, is prepared by treating with a solid adsorbent a non-hydrofined petroleum fraction boiling wholly or mainly between 230‹ and 500‹ C. In this case, oil A has a sulphur content not more than 0À2%, and the proportions are 5-30 parts of B and 1-15 parts of C per 100 parts of A.
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