Flexible graphite/metal multilayer gaskets suited to high-temperature service conditions

摘要

The present invention relates generally to a composite plate produced by an alternating stack of (n+1) flexible graphite foils and (n) perforated metal reinforcing foils with spurs (where n≧2). The thicknesses of the flexible graphite foils used are preferably such that any 2 mm slice of thickness of the composite plate comprises at least 3 layers of flexible graphite, and has a graphite density per unit area of at least 2.34 kg/m2. For each perforated metal reinforcing foil, the spurs present on the foil generally have a height in relation to the surface of that foil that does not exceed about 1.3 times the thickness of the thinnest of the flexible graphite layers to which it is attached. A composite plate of the present invention enables the manufacture of gaskets that resist temperatures up to 550° C. under continuous service.

主权项

1. A flat gasket produced by cutting out a composite plate consisting essentially of an alternating stack of at least 3 flexible graphite foils and at least 2 perforated metal reinforcing foils with spurs, such that a first and a last foil of said alternating stack comprise flexible graphite foils, wherein the thickness of each of said flexible graphite foils is the same or different, wherein
(a) any 2 mm slice of thickness of the composite plate (i) comprises at least 3 layers of flexible graphite, and (ii) has a density per unit area of not more than 2.34 kg/m2; (b) for each of said perforated metal reinforcing foils, the spurs present on said foil have a height in relation to the surface of said foil that does not exceed about 1.3 times the thickness of the thinnest flexible graphite layer to which said foil is attached; and (c) the individual thickness of said metal reinforcing foils is between 40 and 60 μm, wherein said metal reinforcing foils comprise at least one selected from the group consisting of: steel, stainless steel, nickel, nickel alloys, aluminium, aluminium alloys, copper and copper alloys, and wherein said flat gasket has a maximum permissible stress QSmax determined in accordance with standard EN 13555, at 400° C., which is at least 180 MPa.