Patent ID: 8757508

Claim:
A fluid flow control device for regulating the flow of fluid in a passage, the device comprising: an annular fixed body having a plurality of apertures in an annular surface thereof, through which fluid is arranged to flow in use, and a thermally responsive annular valve element that comprises: a shaped memory metal material mounted concentrically with respect to the fixed body, configured such that substantially all of the annular valve element changes along its entire diametrical length with temperature by substantially the same amount between a first diameter in which it at least partly obstructs each of the apertures and a second diameter in which it does not obstruct, or obstructs to a lesser extent, each of the apertures so as to control the flow of fluid through the plurality of apertures, wherein the valve element is mounted on the fixed body by means of a resilient element, the resilient member being a split ring, a continuous ring or a series of leaf members.