Patent ID: 8651142

Claim:
A flow modulating device for modulating flow in a duct, the device comprising: a first flow modulating element having a fixed end secured to a wall of the duct and a free end which is displaceable relative to the wall of the duct; and a first actuation element spaced from the first flow modulating element which only acts on the free end of the first flow modulating element, one of the first flow modulation element and first actuation element are made from a material exhibiting a shape memory effect and the other is a resilient element, wherein: the first flow modulating element and first actuation element assume a first configuration at a first temperature above a transition temperature and assume a second configuration at a second temperature below the transition temperature, the modulus of the material exhibiting a shape memory effect configured to change at the transition temperature such that it overcomes the resilience of the resilient element at the first temperature to assume the first configuration; and the resilient element will overcome the resilience of the material exhibiting a shape memory effect at the second temperature to cause the first flow modulating element to assume the second configuration, the first flow modulating element offering a greater resistance to flow in the duct in one of the configurations than in the other.