Patent ID: 7742153

Claim:
An apparatus for detecting fluctuations in the flow of a fluid comprising: a directional light emitter positioned transverse to the flow of the fluid, further comprising: a flexible arm section having a long axis with a base end and a tip end, wherein the base end is fixed and the tip end is unsupported, to allow the flexible arm section to bend with the flow of the fluid, and wherein the flexible arm section perturbates about a nominal position in response to fluctuations in the flow of the fluid; and a light source connected to the flexible arm section and configured to project a beam of light from the tip end of the flexible arm section; and at least one optical detector positioned to be responsive to the beam of light, wherein the optical detector is configured to sense lateral movements of the beam of light as the flexible arm section perturbates in response to fluctuations in the flow of the fluid and wherein the detector is capable of monitoring lateral movements having frequencies up to 1000 Hz.