Insulating and cooling arrnagement for electrical apparatus

Claim 1

AN INSULATING AND COOLING SYSTEM FOR HIGH VOLTAGE ELECTRICAL APPARATUS OF THE TYPE HAVING SPACED ELEMENTS AT''DIFFERENT POTENTIALS AND A HEAT GENERATING CURRENT CARRYING MEMBER IN A SEALED ENCLOSURE, SAID CURRENT CARRYING MEMBER BEING INSULATED BY SOLID MATERIAL, SAID CURRENT CARRYING MEMBER PRODUCING HEAT CAPABLE OF HEATING THE APPARATUS TO A TEMPERATURE AT WHICH SAID SOLID MATERIAL WILL BE DAMAGED, SAID SYSTEM COMPRISING A HIGH STRENGTH DIELECTRIC GAS THAT IS NON-CONDENSABLE IN THE OPERATING TEMPERATURE RANGE OF SAID APPARATUS, MEANS FOR CIRCULATING SAID GAS OVER SAID CURRENT CARRYING MEMBER SO THAT IT ABSORBES HEAT THEREFROM, MEANS FOR COOLING SAID GAS COMPRISING A HEAT TRANSFER SURFACE OTHER THAN THE SURFACE OF SAID CURRENT CARRYING MEMBER, MEANS DIRECTING FLOW OF SAID GAS OVER SAID HEAT TRANSFER SURFACE, A VAPORIZABLE DIELECTRIC FLUID HAVING A BOILING POINT BELOW THE TEMPERATURE AT WHICH SAID SOLID MATERIAL WILL BE DAMAGED, SAID BOILING POINT BEING WITHIN THE NORMAL OPERATING TEMPERATURE RANGE OF SAID APPARATUS SO THAT SAID DIELICTRIC FLUID CONDENSES AS A LIQUID DURING OPERATION OF SAID APPARATUS, AND MEANS FOR APPLYING A FILM OF THE LIQUEFIED FLUID OVER SAID HEAT TRANSFER SURFACE FOR COOLING THE GAS BY EVAPORATION.