Method for replacing PCB containing coolants in electrical induction apparatus with substantially PCB-free dielectric coolants

Patent · Tue May 17 00:00:00 EDT 1988

OSTI ID:7199227

Atwood, G

A method for replacing a coolant containing PCB in an electrical induction apparatus having a tank containing the coolant, an electrical winding and porous solid cellulosic electrical insulation immersed in the PCB-containing coolant with a substantially PCB-free high boiling dielectric permanent coolant to convert the electrical apparatus into one in which the rate of elution of PCB into the coolant is below the maximum allowable rate of elution into the coolant of an electrical apparatus rated as non-PCB, the solid porous electrical insulation being impregnated with the PCB-containing coolant, is described comprising the steps of: (a) draining the PCB-containing coolant from the tank to remove a major portion of the PCB-containing coolant contained by it; (b) filling the tank with an interim dielectric cooling liquid that is miscible with the PCB, is sufficiently low in viscosity to circulate within the tank and penetrate the interstices of the porous solid electrical insulation, and is capable of being readily separated from the PCB; (c) electrically operating the electrical induction apparatus and continuing the electrical operation for a period sufficient to elute PCB contained in the PCB-containing coolant impregnated in the porous solid insulation therefrom into the interim dielectric cooling liquid; (d) thereafter draining the interim dielectric cooling liquid containing the eluted PCB from the tank; (e) repeating the cycle of steps (b), (c) and (d) when the rate of elution of PCB into the interim dielectric cooling liquid exceeds 0.55 ppm of PCB per day based on the weight of the permanent dielectric coolant; and (f) filling the tank with a substantially PCB-free permanent coolant selected from the group consisting of high boiling, high viscosity, silicone oils, synthetic ester fluids, poly-alpha-olefin oils and hydrocarbon oils so as to reclasify the electrical apparatus to non-PCB status.

• Assignee: Union Carbide Corp., Danbury, CT
• Patent Number(s): US 4744905
• OSTI ID: 7199227
• Resource Relation: Patent File Date: Filed date 3 Jun 1985
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CHLORINATED ALICYCLIC HYDROCARBONS
REMOVAL
COOLING SYSTEMS
PURIFICATION
COOLANTS
DIELECTRIC MATERIALS
ELECTRICAL EQUIPMENT
TANKS
CONTAINERS
ENERGY SYSTEMS
EQUIPMENT
HALOGENATED ALICYCLIC HYDROCARBONS
MATERIALS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
420800* - Engineering- Electronic Circuits & Devices- (-1989)