Isolation gasket, system and method of manufacture

An isolation system that provides an interface between joined flange pieces, each having an inner and an outer face, in a flow line that is operative for fluid passage therethrough without leakage, comprising:

• a flat metal gasket having an opening formed therein to allow fluid passage therethrough, said flat metal gasket having opposing side surfaces on each of which is laminated a layer of dielectric material, each of said side surfaces having portions defining a groove that penetrates through said layer of dielectric material and into said metal plate and extends completely around said opening, and each of said grooves having a layer of insulating material and a seal element disposed therein;
• at least one insulating sleeve receivable in an aligned bore formed in each of said joined flange pieces, said sleeve having a length that is substantially equal to a distance between said outer faces of said joined flange pieces with said gasket interposed therebetween;
• at least one elongate metal fastener having opposing ends, said fastener being receivable in said insulating sleeve for connecting said joined flange pieces to one another with said flat metal gasket interposed therebetween;
• and
• at least one insulating washer receivable on said at least one elongate metal fastener abutting at least one of said flange piece outer faces.

An isolation device for use between joined pieces in a flow line that is operative for fluid passage therethrough without leakage, comprising:

• a flat metal plate having opposing side surfaces and an opening formed therein to allow fluid passage therethrough;
• a layer of dielectric material disposed on at least one of said opposing side surfaces;
• at least one groove formed on said at least one of said opposing side surfaces which penetrates through said layer of dielectric material and into said metal plate and which extends completely around said opening;
• and
• an annular metal seal element coated with an insulating material disposed in said at least one groove.