Flange coupling

The present invention provides a bolted flange coupling comprising a first coupling half (1), a second coupling half (2) and a cylindrical metal seal (3), wherein the metal seal (3) has an outer surface comprising a first inclined annular sealing section (4) and a second inclined annular sealing section (5), and an inner annular surface; the first coupling half (1) comprisesa first connecting element (6), a bore (7) comprising a first recess half (8) comprising an annular seal surface(9) for sealing against the first annular sealing section (4); the second coupling half (2) comprises a second connecting element (10), a bore (11) comprising a second recess half (12) comprising an annular seal surface (13) for sealing against the second annular sealing section (5); the first and the second connecting element comprises a cooperating first connection surface (14) and second connection surface (15), respectively, for connecting the coupling halves (1,2) by use of connecting bolts (16), and at least one of the connecting elements is a flange (17) comprising through-holes (26) for the connecting bolts; the first and the second recess halves (8,12) form a common annular recess (18) when the coupling halves are connected; and wherein the annular recess (18) is arranged to accommodate the metal seal (3), such that the inclined annular sealing sections of the metal seal are sealing against the respective annular seal surfaces (9,13) of the common annular recess (18) when the coupling halves are connected, and the inner annular surface of the metal seal has a minimum diameter being equal to or larger than a minimum diameter of the bores, such that the inner annular surface and the bores form parts of a conduit(19) having a minimum diameter equal to the minimum diameterof the bores. The present invention provides A bolted flange coupling comprising a first coupling half (1), a second coupling half (2) and a cylindrical metal seal (3), wherein the metal seal (3) has an outer surface comprising a first inclined annular sealing section (4), a second inclined annular sealing section (5), a first annular recess (20), a second annular recess (27) and an inner annular surface; the first coupling half (1) comprises a first connecting element (6), a bore (7) comprising a first recess half (8) comprising an annular seal surface (9) for sealing against the first annular sealing section (4); the second coupling half (2) comprises a second connecting element (10), a bore (11) compr