Packing rings, method for production of the packing rings, and seal device using the packing rings

Abstract

A packing ring of a composite structure including a packing of expanded graphite and an annular mass of superposed sheets of expanded graphite is produced by a method including the steps of spirally winding a ribbon of expanded graphite into a roll, compression molding the roll into the packing, and incorporating the annular mass into the packing by compression molding within a molding die so that at least one packed part has a higher density than the packing in at least one of the inner and outer peripheral parts of the packing. A seal device has an empty space through which passes a shaft and containing at least one such packing in the empty space to seal between the inner wall of the empty space and the outer peripheral surface of the shaft.

Dependencies are inferred from the claim text.