The invention relates to a valve, in particular a pendulum or slide gate valve, for essentially gastight closing of a flow path (F). The valve includes a valve housing (1; 1a) having a first wall (2) which has a first opening (3) and a first valve seat (4), a valve disk (5) having a closing side (6) with a sealing ring (7) and at least one drive (8). Through drive (8), the valve disk (5) is pivotable or displaceable from an opened position (A) essentially parallel to the first valve seat (4), and the perpendicular distance between the valve disk (5), and the first valve seat (4) can be reduced so that, in the closed position (C), the flow path (F) is closed essentially gastight by an axially sealing contact between the sealing ring (7) and the first valve seat (4). The valve disk (5) includes an outer disk section (9), which is connected to the drive (8) and fixes the sealing ring (7) in the perpendicular direction to the first valve seat (4), and an inner disk section (10) which has an outer circumferential area (11) and which is mounted so as to be movable relative to the outer disk section (9) in a direction (Z) essentially perpendicular to the first valve seat (4). The outer circumferential area (11) is enclosed essentially gastight with an inner seal by the sealing ring (7). Thus, in the closed position (C), a pressure difference at the valve disk (5) acts essentially on the inner disk section (10) so that the inner disk section (10), decoupled from the outer disk section (9), is supported perpendicularly on a section of the valve housing (1), in particular the first valve seat (4) or a lateral groove (27).