Drainage valve and collection bag assembly comprising said valve

A drainage valve comprising an inlet opening and an outlet opening extending in opposite directions from a valve housing, a movable valve member within the housing and an operating lever connected to the valve member, the valve member movable between an open position in which the valve member is arranged to permit flow through the valve and a closed position where the valve member prevents flow through the valve, wherein the valve member is configured such that the valve member is moved from the closed position to the open position by rotating the operating lever by a first rotating angle that is between 2 degrees to 80 degrees relative to the flow direction in the valve housing, and wherein the valve has a design in which the operating lever is arranged for being rotated by a second rotating angle to a fully open position after completion of the first rotating angle, with a total of the first and second rotation angles defining an operating angle of between 140 to 180 degrees, and wherein the valve is in the fully open position after rotation of the first rotating angle and remains in the fully open position after rotation of the second rotating angle, and wherein the valve is configured such that the operating lever is generally flush with one or more elements attached to the inlet opening when the valve is in the closed position and the operating lever is generally flush with one or more elements attached to the outlet opening when the valve is in the fully open position.