| 摘要 |
<p>A refractive velocimeter apparatus (11) for measuring fluid velocity in a stack (S) includes an optical instrument (26, 27) positioned on the stack for generating an optical signal, which instrument includes a lens (48) for collimating light and positioned for directing the collimated light along a first direction through the stack and through the fluid flowing within the stack, and a first reflector (41) 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 (46) is positioned for reflecting collimated light away from the second path and out of the instrument as the optical signal. A laser (13) is positioned remotely of the stack and light from the laser is provided to the optical instrument through a fiber optic cable (17, 18). The optical signal from the optical instrument is transmitted through another fiber optic cable to a signal evaluation unit (15) 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.</p> |
