Process for improving the electrically insulating properties of compacted, pulverulent, insulating materials

Claim 1

A PROCESS FOR IMPROVING THE ELECTRICAL INSULATING PROPERTIES OF A MASS OF COMPLETED, POROUS, PULVERLENT, FINELY-DIVIDED ELECTRICAL INSULATING MATERIAL IN AN ELECTRICAL ASSEMBLY COMPRISING ONE OR MORE ELECTRICAL CONDUCTORS HOUSED IN A RIGID, IMPERFORATE SHEATH COEXTENSIVE LONGITUDINALLY WITH THE CONDUCTORS, SAID MASS OF COMPACTED, POROUS, PULVERULENT ELECTRICAL INSULATING MATERIAL SPACING SAID CONDUCTORS FROM EACH OTHER AND FRROM SAID SHEATH, THE ENDS OF THE SHEATH BEING OPEN TO EXPOSE THE INSULATING MATERIAL, SAID PROCESS CONSISTING ESSENTIALLY OF THE STEPS OF: PLACING SAID ELECTRICAL ASSEMBLY IN AN OVEN AND DESICCATING THE MASS OF INSULATING MATERIAL IN SAID OVEN UNDER APPLIED HEAT AT A TEMPERATURE OF FROM 350* TO 450*F. FOR AT LEAST THREE HOURS TO DRIVE OFF ALL OCCLUTED MOISTURE FROM THE POROSITIES OF SAID MATERIAL; PROVIDING, IN CLOSE PROXIMITY TO THE OVEN, A BATH OF A HEAT-CURABLE LIQUID SEALANT OPEN TO THE ATMOSPHERE AND AT ROOM TEMPERATURE, SAID LIQUID SEALANT HAVING A VISCOSITY AT THAT PRESSURE AND TEMPERATURE SUFFICIENTLY LOW THAT THE POROSITIES OF THE INSULATING MATERIAL WILL BE INFILTRATED BY THE LIQUID SOLELY BY CAPILLARY ATTRACTION; REMOVING SAID ASSEMBLY FROM SAID OVEN AND IMMEDIATELY PLACING IT IN SAID BATH; ALLOWING THE ASSEMBLY TOREMAIN IMMERSED IN SAID LIQUID SEALANT FOR AT LEAST SUBSTANTIALLY FOUR HOURS UNTIL SAID INSULATING MASS IS COMPLETELY PENETRATED BY SAID SEALANT BY CAPILLARY ATTRACTION; TRANSFERRING THE ASSEMBLY TO AN OVEN FOR CURING THE SEALANT AT A TEMPERATURE RANGING FROM 350* TO 650*F. FOR A PERIOD OF FROM THREE TO SIX HOURS; AND REMOVING THE ASSEMBLY FROM SAID LAST MENTIONED OVEN.