METHODS FOR DIELECTRICALLY INSULATING ELECTRICAL ACTIVE PARTS

Abstract

The invention concerns methods for dielectrically insulating electrical active parts using certain fluorinated dicarbonyl compounds as well as compositions and apparatus comprising such compounds.

Claims

1. A method for dielectrically insulating an electrical active part wherein the electrical active part is arranged in a gas-tight housing comprising an insulating medium consisting of, consisting essentially of, or comprising a compound of general formula (I):
R.sup.1(O).sub.nC(O)ZC(O)(O).sub.mR.sup.2(I) wherein Z is a single bond, O, NH, NR.sup.3, an alkylidene group, a partially fluorinated alkylidene group or a perfluorinated alkylidene group; and R.sup.1, R.sup.2 and R.sup.3 are independently a partially fluorinated or perfluorinated alkyl group; or R.sup.1 and R.sup.2 together form a partially fluorinated or perfluorinated alkylidene group and R.sup.3 is a partially fluorinated or perfluorinated alkyl group; and n and m are independently 0 or 1.

2. The method according to claim 1 wherein n and m are 0.

3. The method according to claim 1 wherein Z is a single bond or a perfluorinated alkylidene group.

4. The method according to claim 1 wherein R.sup.1 and R.sup.2 are independently C.sub.nF.sub.2n+1.

5. The method according to claim 1 wherein R.sup.1 and R.sup.2 are CF.sub.3 or C.sub.2F.sub.5.

6. The method according to claim 1 wherein the compound is CF.sub.3C(O)CF.sub.2C(O)CF.sub.3, CF.sub.3C(O)C(O)CF.sub.3, CF.sub.3CF.sub.2C(O)CF.sub.2C(O)CF.sub.2CF.sub.3, or CF.sub.3CF.sub.2C(O) C(O)CF.sub.2CF.sub.3.

7. The method according to claim 1 wherein the insulating medium comprises the compound of formula (I) and at least one further compound selected from the group consisting of an inert gas, a perfluorinated monoketone, partially fluorinated monoketone, a perfluorinated ether, partially fluorinated ether, a perfluorinated cyano compound, partially fluorinated cyano compound, and a hydrocarbon compound.

8. The method according to claim 7 wherein the at least one compound is an inert gas selected from the group consisting of air, synthetic air, an air component, N.sub.2, O.sub.2, CO.sub.2, N.sub.2O, He, Ne, Ar, Xe and SF.sub.6.

9. A composition consisting of, consisting essentially of, or comprising at least one compound of general formula (I)
R.sup.1OC(O)ZC(O)O.sub.mR.sup.2(I) wherein Z is a single bond, O, NH, NR.sup.3, an alkylidene group, a partially fluorinated alkylidene group or a perfluorinated alkylidene group; and R.sup.1, R.sup.2 and R.sup.3 are independently a partially fluorinated or perfluorinated alkyl group; or R.sup.1 and R.sup.2 together form a partially fluorinated or perfluorinated alkylidene group and R.sup.3 is a partially fluorinated or perfluorinated alkyl group; and n and m are independently 0 or 1; and at least one further compound selected from the group consisting of an inert gas, a perfluorinated monoketone, partially fluorinated monoketone, a perfluorinated ether, partially fluorinated ether, a perfluorinated cyano compound, partially fluorinated cyano compound, and a hydrocarbon compound.

10. The composition according to claim 9 consisting of, consisting essentially of, or comprising CF.sub.3C(O)CF.sub.2C(O)CF.sub.3, CF.sub.3C(O)C(O)CF.sub.3, CF.sub.3CF.sub.2C(O)CF.sub.2C(O)CF.sub.2CF.sub.3, or CF.sub.3CF.sub.2C(O) C(O)CF.sub.2CF.sub.3, and at least one compound selected from the group consisting of an inert gas, a perfluorinated monoketone, partially fluorinated monoketone, a perfluorinated ether, partially fluorinated ether, a perfluorinated cyano compound, partially fluorinated cyano compound, and a hydrocarbon compound.

11. The composition of claim 9 consisting of, consisting essentially of, or comprising CF.sub.3C(O)CF.sub.2C(O)CF.sub.3 and at least one compound selected from the group consisting of air, synthetic air, an air component, N.sub.2, O.sub.2, CO.sub.2, N.sub.2O, He, Ne, Ar, Xe and SF.sub.6.

12. An apparatus for the generation, distribution and/or usage of electrical energy wherein the apparatus comprises an electrical active part arranged in a gas-tight housing, said gas-tight housing containing an insulating medium consisting of, consisting essentially of, or comprising at least one compound of general formula (I)
R.sup.1(O).sub.nC(O)ZC(O)(O).sub.mR.sup.2(I) wherein Z is a single bond, O, NH, NR.sup.3, an alkylidene group, a partially fluorinated alkylidene group or a perfluorinated alkylidene group; and R.sup.1, R.sup.2 and R.sup.3 are independently a partially fluorinated or perfluorinated alkyl group; or R.sup.1 and R.sup.2 together form a partially fluorinated or perfluorinated alkylidene group and R.sup.3 is a partially fluorinated or perfluorinated alkyl group; and n and m are independently 0 or 1; or containing an insulating medium consisting of, consisting essentially of, or comprising the composition according to claim 9.

13. The apparatus of claim 12 wherein the insulating medium consists of, consists essentially of, or comprises CF.sub.3C(O)CF.sub.2C(O)CF.sub.3, CF.sub.3C(O)C(O)CF.sub.3, CF.sub.3CF.sub.2C(O)CF.sub.2C(O)CF.sub.2CF.sub.3, or CF.sub.3CF.sub.2C(O) C(O)CF.sub.2CF.sub.3.

14. The apparatus of claim 12 wherein the apparatus is a switchgear.

15. The method according to claim 3 wherein Z is CF.sub.2.

16. The method according to claim 6 wherein the compound is CF.sub.3C(O)CF.sub.2C(O) CF.sub.3.

17. The method according to claim 8 wherein the at least one compound is N.sub.2.

18. The composition according to claim 10 consisting of, consisting essentially of, or comprising CF.sub.3C(O)CF.sub.2C(O)CF.sub.3.

19. The composition of claim 11 consisting of, consisting essentially of, or comprising CF.sub.3C(O)CF.sub.2C(O)CF.sub.3 and N.sub.2.

20. The apparatus of claim 13 wherein the insulating medium consists of, consists essentially of, or comprises CF.sub.3C(O)CF.sub.2C(O)CF.sub.3.

Description

EXAMPLES

Example 1a

Manufacture of CF3C(O)CF2C(O)CF3

[0044] CF.sub.3C(O)CF.sub.2C(O)CF.sub.3 was prepared according to Conti, S. et al., Acta Chimica Slovenica, 2013, 60(3), 556-560.

Example 1b Manufacture of the Compositions

[0045] As described in WO98/23363, a homogenous mixture consisting CF.sub.3C(O)CF.sub.2C(O)CF.sub.3 and N.sub.2 in a volume ratio 1:4 is manufactured in an apparatus comprising a static mixer and a compressor.

Example 2

Provision of an Earth Cable Containing the Dielectrically Insulating Medium of Example 1

[0046] The composition of example 1b is directly fed into an earth cable for high voltage, until a total pressure of 10 bar (abs) is achieved in the cable.

Example 3

A Switchgear Containing CF.SUB.3.C(O)CF.SUB.2.C(O)CF.SUB.3 .and N.SUB.2 .in a Volume Ratio 1:4

[0047] A switchgear is used which contains a switch surrounded by a gas-tight metal case. The composition of example b1 is passed into the gas tight metal case via a valve until a pressure of 18 bar (abs) is achieved.