摘要 |
A refractive velocimeter apparatus for measuring fluid velocity in a stack includes an optical instrument positioned on the stack for generating an optical signal, which instrument includes a lens for collimating light and positioned for detecting the collimated light along a first direction through the stack and through the fluid flowing within the stack, and a first reflector positioned for reflecting at least some of the collimated light along a second direction, parallel and opposite to the first direction, through the stack and through the fluid flowing through the stack. A second reflector is positioned for reflecting collimated light away from the second path and out of the instrument as the optical signal. A laser is positioned remotely of the stack and light from the laser is provided to the optical instrument through a fiber optic cable. The optical signal from the optical instrument is transmitted through another fiber optic cable to a signal evaluation unit positioned remotely of the stack and which is adapted for evaluating a frequency of the optical signal for determining the velocity of the fluid flowing in the stack.
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