Device for providing a uniformly-variable annular orifice

摘要

A device (20) for providing a uniformly-variable orifice includes an object (21) having an outer surface, a wall (24) surrounding the object in spaced relation to the outer surface and defining an annular orifice therebetween; and deforming means (F1) for causing at least one of the surface and wall to move perpendicularly and uniformly toward the other of the surface and wall without substantially altering the geometric shape of the annular orifice, whereby the movable member may be moved relative to the other to vary the area of the orifice. In the preferred embodiment, the area of the orifice varies substantially linearly with application of the deforming displacement.