Discharge regulator

An apparatus for ensuring a uniform rate of flow out of reservoir includes an outflow opening and an upstream adjustable throttling device in the form of a segment of a curve (28) connected to the arm (34) of a float (36) which follows the level of the liquid. The segment and the arm are carried at the centre of curvature of the segment on a common horizontal spindle (26) on a support structure (18), and the edge of the outflow opening is defined by a rectangular shroud (16) extending into the reservoir as far as the path described by the curved segment (28). An open-bottomed bell housing (56) encloses the arrangement, and the float (36) follows the liquid level inside the bell housing, which reflects the level of liquid in the reservoir on a reduced non- linear scale. A spring device (62) acts on the float a section of the movement of the curved segment corresponding to small areas of opening. The characteristic of the spring steplessly opposes the buoyancy force of the float.