FLOW CONTROL DEVICE

摘要

A flow control device comprises an outer sleeve (13) having at least one aperture (14) through its wall, an inner sleeve (15) having at least one aperture (16) through its wall and means for providing relative sliding movement of the sleeves between "open" positions allowing variable flow of fluid through the apertures of the sleeves and "closed" positions, characterised by a pressure-reducing region (22) arranged to reduce the pressure of fluid flowing through the at least one aperture of one of the sleeves.