Patents by Inventor Pietro Metra

Pietro Metra has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Direct current cable insulation with insulating composition including electronegative gas
    Patent number: 4774382
    Abstract: A direct current electric cable with a conductor, a semi-conductive screen around and contacting the conductor, a plurality of layers of insulation formed by tapes of insulating material around the semi-conductive screen, a further semi-conductive screen around the layers of insulation and a metal sheath around the further semi-conductive screen, the layers of insulation being impregnated with a non-migrating, insulation composition having a dropping point temperature at least 5.degree. C. above the maximum operating temperature of the cable and having an electronegative gas dissolved therein, the gas having a coefficient of diffusion in the composition in the range from 3.times.10.sup.-5 to 3.times.10.sup.-6 cm.sup.2 /sec at temperatures below the dropping point temperature of the composition.
    Type: Grant
    Filed: July 16, 1987
    Date of Patent: September 27, 1988
    Assignee: Societa' Cavi Pirelli S.p.A.
    Inventors: Paolo G. Priaroggia, Gianmario Lanfranconi, Pietro Metra, Gianni Miramonti