Patent ID: 8628697

Claim:
A method for producing a dielectric fluid free of antioxidants and/or external additives; the method comprises the steps of: mixing two or more crude vegetable oils, wherein said vegetable oils are from 95.5% to 99.25% by weight of at least one high oleic vegetable oil selected from a group of consisting of low erucic rapeseed oil, high oleic sunflower oil, high oleic safflower oil, and combinations thereof; from 0.25% to 1.5% by weight of grape seed oil; from 0.25% to 1.5% by weight of sesame seed oil; and from 0.25% to 1.5% by weight of rice bran oil; removing hydrophibic phospholipids and non-hydrophobics from the mixture of vegetable oils, by adding food grade citric acid within a temperature-controlled reactor; distilling under high vacuum the mixture of vegetable oils to remove free fatty acids present; removing impurities from the mixture of vegetable oils, shaking it under a direct dry steam in a high-vacuum chamber with convection heat coils; and filtering the mixture of vegetable oils by a barrier filter system to remove the remaining impurities; wherein said dielectric fluid has: a dielectric strength of 40 kV to 70 kV at a separation of 2 mm; a dielectric constant of 2.5 to 3.1 at 25° C.; and a dissipation factor of 0.05% to 0.15% at 75° C.