The present invention refers to a new conception of membrane valve for controlling flow and pressure relief, which has a format following the anatomy and the action mechanism of a sphincter, in order not to have restriction points to the fluid flow. The valve according to the present invention comprises a body (2) provided with terminal sections (3, 4) provided with ends (5, 6) and, internally, a folded membrane (7) which opens and closes according to the flow and/or pressure exerted therein, directly or indirectly, locally or remotely.
