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) having a first wall (2) which has a first opening (3) and a first valve seat (4), a valve plate (5) having a closing side (6) with a first sealing ring (7) and at least one drive (8). By action of the drive (8), the valve plate (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 plate (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 first sealing ring (7) and the first valve seat (4). The valve plate (5) includes support part (9), which is connected to the drive (8) and fixes the first sealing ring (7) in the perpendicular direction to the first valve seat (4), and a sealing part (10) which has an inner circumferential area (11) and which is mounted so as to be movable relative to the support part (9) in a direction (Z) essentially perpendicular to the first valve seat (4). The inner circumferential area (11) encloses the first sealing ring (7) in an essentially gastight way with an inner seal. Thus, in the closed position (C), a pressure difference at the valve plate (5) acts essentially on the sealing part (10) so that sealing part (10), decoupled from the support part (9), is supported perpendicularly on a section of the valve housing (1), in particular the first valve seat (4) or a lateral groove (27).