PRESSURE LOSS FOLLOW-UP TYPE MOVABLE ORIFICE

PROBLEM TO BE SOLVED: To provide a pressure loss follow-up type movable orifice which can conduct balance adjustment between the pressure loss at a unit body side of a boiler and the pressure loss at a spray water piping system side in the movable orifice which is applied to a water supply system of an electric power plant and capable of following and coping with the alteration of pressure loss of the system. SOLUTION: Fixing shafts and movable shafts are protrusively set at the end portions of a plurality of arched movable plates 2 and fitted to the holes in a tap plate 3 and the grooves on a rotary plate 4, thus constructing an orifice plate 1 by superposing the tap plate 3, the movable plates 2 and the rotary plate 4. When the rotary plate 4 is driven, the movable plates 2 are moved to vary the opening area of the orifice plate 1, thereby coping with the pressure alteration at an upstream and a downstream.